DNV-OS-B101-Metallic Materials
DNV material and welding
RULES FOR CLASSIFICATION OFThe content of this service document is the subject of intellectual property rights reserved by Det Norske Veritas AS (DNV). The user accepts that it is prohibited by anyone else but DNV and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV's prior written consent. DNV is not responsible for the consequences arising from any use of this document by others.The electronic pdf version of this document found through is the officially binding version Ships / High Speed, Light Craft and Naval Surface CraftPART 2 CHAPTER 2NEWBUILDINGSMATERIALS AND WELDINGMetallic MaterialsJULY 2013FOREWORDDNV is a global provider of knowledge for managing risk. Today, safe and responsible business conduct is both a license to operate and a competitive advantage. Our core competence is to identify, assess, and advise on risk management. From our leading position in certification, classification, verification, and training, we develop and apply standards and best practices. This helps our customers safely and responsibly improve their business performance. DNV is an independent organisation with dedicated risk professionals in more than 100 countries, with the purpose of safeguarding life, property and the environment.The Rules lay down technical and procedural requirements related to obtaining and retaining a Class Certificate. It is used as a contractual document and includes both requirements and acceptance criteria.© Det Norske Veritas AS July 2013Any comments may be sent by e-mail to rules@Rules for Ships / High Speed, Light Craft and Naval Surface Craft, July 2013Pt.2 Ch.2 Changes – Page 3 CHANGES – CURRENTGeneralThis document supersedes the January 2013 edition.Text affected by the main changes in this edition is highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.Main changes coming into force 1 January 2014•Sec.7 Steel Castings—The Figures 3, 4, 5 and 6 have been updated in order to be in line with IACS UR W24.Editorial CorrectionsIn addition to the above stated main changes, editorial corrections may have been made.CONTENTSCHANGES – CURRENT (3)Sec. 1Rolled Steel for Structural Application (10)A.General Requirements (10)A100Scope (10)A200Grading system (10)A300Manufacture (10)A400Chemical composition (10)A500Condition of supply and heat treatment (11)A600Test material and test pieces for mechanical testing (11)A700Test units and number of tests (14)A800Mechanical properties (14)A900Inspection and tolerances (14)A1000Repair (14)A1100Identification (15)A1200Certification (15)B.Normal Strength Steel (15)B100Scope (15)B200Chemical composition (16)B300Condition of supply (16)B400Mechanical properties (16)C.High Strength Steel (17)C100Scope (17)C200Chemical composition (17)C300Condition of supply (18)C400Mechanical properties (18)D.Extra High Strength Steel (19)D100Scope (19)D200Chemical composition (19)D300Condition of supply (19)D400Mechanical properties (19)E.Plates with Through Thickness Properties (20)E100Scope (20)E200Manufacture (21)E300Chemical composition (21)E400Test material (21)E500Mechanical testing (21)E600Ultrasonic testing (21)Sec. 2Rolled Steel for Boilers, Pressure Vessels and Special Applications (22)A.General (22)A100Scope (22)A200Method of manufacture (22)A300General for testing (22)A400Tensile testing at ambient temperature (22)A500Tensile testing at high temperatures (22)A600Impact testing (22)A700Drop weight testing (23)A800Testing of through thickness properties (23)A900Inter-crystalline corrosion testing (23)A1000Inspection, Dimensional Tolerances and Surface Condition Inspection (23)A1100Tolerances (23)A1200Surface condition and rectification of defects (23)B.Steel for Boilers and Pressure Vessels (24)B100Steel grades (24)B200Chemical composition (24)B300Mechanical properties (24)B400Heat treatment (24)C.Steel for Low Temperature Service (28)C100Steel grades (28)C400Heat treatment (29)D.Stainless Steel (31)D100Steel grades (31)D200Chemical composition (31)D300Mechanical properties (32)D400Heat treatment (32)D500Intercrystalline corrosion tests (32)Sec. 3Clad Steel Plates (33)A.General (33)A100Scope (33)A200Heat treatment (33)B.Base Material (33)B100General (33)C.Cladding Metal (33)C100General (33)C200Chemical composition (33)D.Testing (33)D100General (33)D200Tensile testing (33)D300Impact testing (34)D400Bend testing (34)D500Shear testing (34)D600Ultrasonic testing (34)D700Corrosion testing (34)D800Inspection — tolerances (34)E.Repair and Rejection (34)E100Surface defects (34)E200Rejection (34)F.Identification of Materials (35)F100Branding (35)Sec. 4Steel Pipes (36)A.General Requirements (36)A100Scope (36)A200Manufacture (36)A300Chemical composition (36)A400Heat treatment (36)A500Mechanical testing (36)A600Leak tightness testing (37)A700Inspection (37)A800Repair (37)A900Identification (37)A1000Certification (37)B.Pressure Pipes (37)B100Scope (37)B200Manufacture (37)C.Stainless Steel Pipes (38)C100Scope (38)C200Manufacture (38)C300Mechanical testing (38)C400Corrosion testing (38)D.Pipes for Low-temperature Service (38)D100Scope (38)D200Manufacture (38)D300Mechanical testing (39)E.Boiler and Superheater Tubes (39)E100Scope (39)E200Manufacture (39)F.Piping Fittings (39)F300Testing and inspection (40)F400Certification (40)Sec. 5Steel Forgings (41)A.General Requirements (41)A100Scope (41)A200Grading system (41)A300Manufacture (41)A400Chemical composition (42)A500Heat treatment (42)A600Test material and test pieces for mechanical testing (42)A700Test units and number of tests (43)A800Mechanical properties (43)A900Inspection (44)A1000Repair (44)A1100Identification (45)A1200Certification (45)B.Forgings for Hull Structures and Equipment (45)B100Scope (45)B200Chemical composition (45)B300Heat treatment (45)B400Mechanical testing (46)B500Inspection (46)C.Forgings for Shafting and Machinery (46)C100Scope (46)C200Chemical composition (46)C300Heat treatment (47)C400Mechanical testing (47)C500Inspection (47)D.Forgings for Crankshafts (49)D100Scope (49)D200Chemical composition (49)D300Heat treatment (49)D400Mechanical testing (49)D500Inspection (49)E.Forgings for Gearing (49)E100Scope (49)E200Chemical composition (50)E300Heat treatment (50)E400Mechanical testing of forgings not intended for carburising (50)E500Testing of forgings for carburising applications (50)E600Inspection (50)F.Forgings for Boilers, Pressure Vessels and Piping Systems (52)F100Scope (52)F200Chemical composition (52)F300Heat treatment (52)F400Mechanical properties (52)F500Inspection (52)F600Pressure testing (52)G.Ferritic Steel Forgings for Low Temperature Service (53)G100Scope (53)G200Chemical composition (53)G300Heat treatment (53)G400Mechanical properties (53)G500Inspection (53)G600Pressure testing (54)H.Stainless Steel Forgings (54)H100Scope (54)H200Manufacture (54)H300Mechanical properties (54)H400Inspection (54)Sec. 6Bars for Chain Cables (55)A500Heat treatment (55)B.Testing (55)B100Test units, test material and number of tests (55)B200Mechanical properties (56)C.Inspection, Tolerances and Repair (56)C100Inspection and tolerances (56)C200Repair (56)D.Identification and Certification (56)D100Marking (56)D200Certification (56)Sec. 7Steel Castings (57)A.General Requirements (57)A100Scope (57)A200Grading system (57)A300Manufacture (57)A400Chemical composition (57)A500Heat treatment (57)A600Test blocks and test pieces for mechanical testing (58)A700Test units and number of tests (58)A800Mechanical properties (58)A900Inspection (58)A1000Repair (60)A1100Identification (60)A1200Certification (61)B.Castings for Hull Structures and Equipment (61)B100Scope (61)B200Chemical composition (61)B300Heat treatment (61)B400Mechanical properties (61)B500Inspection (62)C.Castings for Machinery (62)C100Scope (62)C200Chemical composition (62)C300Heat treatment (62)C400Mechanical properties (63)C500Inspection (63)D.Castings for Propellers (63)D100Scope (63)D200Chemical composition (63)D300Heat treatment (63)D400Mechanical testing (63)D500Inspection (64)D600Repair (64)D700Welding procedure qualification test (65)E.Castings for Boilers, Pressure Vessels and Piping Systems (69)E100Scope (69)E200Chemical composition (69)E300Heat treatment (69)E400Mechanical properties (69)E500Inspection (69)E600Pressure testing (69)F.Ferritic Steel Castings for Low Temperature Service (70)F100Scope (70)F200Chemical composition (70)F300Heat treatment (70)F400Mechanical properties (70)F500Inspection (70)F600Pressure testing (70)G500Inspection (71)Sec. 8Iron Castings (73)A.General (73)A100Scope (73)A200Quality of castings (73)A300Manufacture (73)A400Chemical composition (73)A500Heat treatment (73)A600Testing (73)A700Visual and non-destructive examination (73)A800Repair of defects (74)B.Nodular Cast Iron (74)B100Scope (74)B200Test material (74)B300Mechanical properties (76)B400Metallographic examination (76)C.Grey Cast Iron (76)C100Scope (76)C200Test material (76)C300Mechanical properties (78)Sec. 9Aluminium Alloys (79)A.Wrought Aluminium Alloys (79)A100Scope (79)A200Aluminium grades and temper conditions (79)A300Manufacture (79)A400Chemical composition (79)A500Test material and test pieces for mechanicaltesting (79)A600Test units and number of tests (80)A700Mechanical properties (80)A800Press weld testing (80)A900Corrosion testing (80)A1000Inspection and tolerances (81)A1100Repair (81)A1200Identification (81)A1300Certification (81)Sec. 10Copper Alloy Castings (84)A.General Requirements (84)A100General (84)A200Grading system (84)A300Manufacture (84)A400Chemical composition (84)A500Heat treatment (84)A600Test blocks and test pieces for mechanical testing (84)A700Test units and number of tests (85)A800Mechanical properties (85)A900Inspection (85)A1000Repair (86)A1100Identification (86)A1200Certification (86)B.Castings for Valves, Fittings and General Application (86)B100Scope (86)B200Chemical composition (86)B300Heat treatment (87)B400Mechanical properties (87)B500Inspection (87)B600Repair (87)C.Castings for Propellers (88)C100Scope (88)C400Mechanical testing (88)C500Inspection (88)C600Repair (88)C700Identification (89)C800Certification (89)C900Welding procedure qualification (89)Sec. 11Non-ferrous Tubes (92)A.Copper and Copper Alloy Tubes (92)A100Scope (92)A200Manufacture (92)A300Chemical composition (92)A400Heat treatment (92)A500Mechanical testing (92)A600Inspection (92)A700Repair (92)A800Identification (92)A900Certification (92)B.Titanium and Titanium Alloy Tubes (93)B100Scope (93)B200Manufacture (93)B300Certification (93)CHANGES – HISTORIC (94)SECTION 1 ROLLED STEEL FOR STRUCTURAL APPLICATIONA. General RequirementsA 100Scope101 This sub-section specifies the general requirements for hot rolled steel plates, strips, sections and bars to be used in the construction of hulls and other marine structures. These requirements are also applicable to seamless steel pipes intended for structural application.102 The requirements apply to plates and wide flats not exceeding 150 mm in thickness and sections and bars not exceeding 50 mm in thickness. For greater thicknesses, variations in the requirements may be permitted for particular applications.103 Where required by the relevant design and construction parts of the rules, steel shall comply with the requirements of Ch.1, the general requirements of A and the appropriate specific requirements of B to E. If the specific requirements differ from these general requirements, the specific requirements shall prevail.104 As an alternative to 103, materials which comply with other standards or proprietary specifications may be accepted provided such specifications give reasonable equivalence to the requirements of this section or are approved for a specific application (e.g. seamless and welded steel pipes and hollow sections for structural application). Generally, such materials shall comply with the appropriate requirements of Ch.1.A 200Grading system201 The steel products concerned are classified by strength into three groups: normal strength, high strength and extra high strength steel. Each strength group is further subdivided into grades, as given in B to D.202 Supplementary requirements for steel grades with specified through thickness properties – ‘Z’ grade steel – are given in E.A 300Manufacture301 All materials delivered with NV or works certificate shall be made at works approved by the Society for the type and grade of steel being supplied and for the relevant steelmaking and processing route. Rolling mills without own steelmaking may only use starting material supplied by works approved by the Society.302 Steel shall be manufactured by the open hearth, an electric or one of the basic oxygen processes or any other process involving secondary refining approved by the Society.303 Steel shall be cast in metal ingot moulds or by continuous casting. Sufficient discard shall be made to ensure soundness in the finished product. The size of the ingot, billet or slab shall be proportional to the dimensions of the final product such that the cross section reduction ratio or, in the case of slab to plate, thickness reduction ratio shall normally be at least 3 to 1.304 Conditions of supply shall be in accordance with 500.305 It is the manufacturer’s responsibility to ensure that effective manufacture and process controls are implemented in production. Where deviation from the controls occurs and this could produce products of inferior quality, the manufacturer shall investigate to determine the cause and establish countermeasures to prevent its recurrence. Investigation reports to this effect shall be made available to the surveyor on request.A 400Chemical composition401 The chemical composition of each heat shall be determined on a sample taken preferably during the pouring of the heat and shall be within the specified limits in B to E. When multiple heats are tapped into a common ladle, the ladle analysis shall apply and be within the specified limits. Variations from the chemical compositions given may be allowed for grades supplied in the thermo-mechanical rolled condition or when thicknesses exceed 50 mm provided that these variations are approved.402 The composition shall be determined after all alloying additions have been made and sufficient time allowed for such an addition to homogenize.403 Elements designated as residual elements in the individual specifications shall not be intentionally added to the steel. The content of such elements shall be reported.404 When recycled scrap or contaminated ore is used in steelmaking, adequate controls shall be in place to prevent accumulation of harmful elements in the final product. The content of impurity elements such as tin, antimony and arsenic may be required determined.405 When required, the carbon equivalent value shall be calculated from the heat analysis using the formula:Subject to agreement, the weldability may alternatively be evaluated by calculating the cold crackingsusceptibility using the formula:406 The requirements for elements designated as fine grain elements (Al, Nb, V and Ti) are given in eachsub-section B to E. When fine grain elements are used in combination, the minimum limits are given as follows:Al; 0.015%, Nb: 0.010%, V: 0.030%, Ti: 0.007%. Each combination of fine grain elements is subject to approval through the approval of manufacturer process, and is listed on the approval of manufacturer certificates. The applicable combination of fine grain elements shall, unless otherwise approved, follow the minimum and maximum limits given here and in sub-sections B to E.A 500Condition of supply and heat treatment501 Conditions of supply shall be in accordance with requirements given in B to D and as defined in 502 to 506. Where alternative conditions are permitted, the manufacturer shall supply materials only in those conditions for which he has been approved.502 As-rolled (AR) refers to conventional rolling at high temperature followed by air cooling. The rolling temperature and reduction may not be accurately controlled resulting in variable grain sizes and, hence,variable mechanical properties.503 Normalising rolling (NR) is a rolling procedure in which the final rolling temperature is controlled within a certain range above the Ar3 temperature so that the austenite completely re-crystallises. After the final pass,air cooling produces a fine grained ferrite-pearlite microstructure comparable to that obtained after normalising heat treatment.504 Thermo-mechanical rolling (TM) is a rolling procedure in which both the rolling temperatures and reductions and, when used, accelerated cooling conditions are controlled. Generally, a high proportion of the rolling reduction is carried out close to the Ar3 temperature and may involve the rolling in the austenite-ferrite dual phase temperature region. After the final pass, either air cooling or accelerated cooling, excluding quenching, is used. Final rolling in the same temperature range as used for NR followed by accelerated cooling is considered to be a TM procedure. Unlike NR the properties conferred by TM cannot be reproduced by subsequent normalising heat treatment.505 Normalising (N) is a separate heat treatment after rolling involving austenitising and air cooling to produce a fine grained ferrite-pearlite microstructure.506 Quenching and Tempering (QT) is a separate heat treatment after rolling involving austenitising, rapid cooling for hardening and subsequent reheating to produce a tempered martensite microstructure.507 It is the manufacturer's responsibility to ensure that the programmed rolling schedules for NR and TM are adhered to. Production records to this effect shall be made available to the surveyor on request. Where deviation from the programmed rolling schedules occurs, the manufacturer must ensure that each affected rolled piece is tested and that an investigation is carried out according to 305.508 Other delivery conditions than those listed above may be accepted based on special evaluation and approval. Extended qualification through the approval of manufacturer process will be considered for each relevant case. The approved delivery conditions are listed on the approval of manufacturer certificates.A 600Test material and test pieces for mechanical testing601 Test material shall be fully representative of the sample product and, where appropriate, shall not be cut from the sample product until heat treatment has been completed. Test material or test pieces shall not be separately heat treated in any way.602 Test material shall be suitably marked to identify them with the products represented.603 Test material shall be taken from the following positions:—Plates and wide flats with a width ≥ 600 mmThe test material shall be taken at the square cut end approximately one-quarter width from an edge, see Fig. 1a.C eq C Mn 6--------Cr Mo V ++5-------------------------------Ni Cu+15------------------- (%)+++=P cm C Si 30-----Mn Cu Cr ++20----------------------------------Ni 60-----Mo 15--------V 10-----5B %()++++++=—Flats with a width < 600 mm, bulb flats and other sectionsThe test material shall be taken at approximately one-third of the width from an edge, see Figs. 1b, 1c, 1d and 1e. For channels and beams, an alternative position is shown in Fig. 1d.—Bars and other similar productsThe test material shall be taken at a depth one-third of the radius below the surface or, in the case of non-cylindrical sections, at a depth one-third of the half-diagonal from the surface, see Fig. 1f.604 The following definitions relevant to orientation of test pieces apply:Longitudinal: longitudinal axis of test piece parallel to the principal direction of rolling.Transverse: longitudinal axis of test piece perpendicular to the principal direction of rolling.605 Unless otherwise agreed, the test pieces shall be oriented as follows:—Plates and wide flats with a width ≥ 600 mmTensile test pieces shall be transverse. Impact test pieces shall be longitudinal, except that for extra high strength steel, transverse tests are required.—Flats with a width < 600 mm, bulb flats and other sectionsTensile and impact test pieces shall be longitudinal.—Bars and other similar productsTensile and impact test pieces shall be longitudinal.606 The preparation of test pieces and the procedures used for mechanical testing shall comply with the relevant requirements of Ch.1. See also 607 and 608.607 For impact test pieces, the notch shall be cut in a face of the test piece which was originally perpendicular to a rolled surface.608 Impact test pieces for plates and sections shall be cut from a position within 2 mm of a rolled surface, except that for plates and sections over 40 mm thick, the axes of the test pieces shall be at one-quarter of the thickness from a rolled surface.WidthFig. 1Position of test materialA 700Test units and number of tests701 Depending on product and grade, provision is made in B to E for testing of individual pieces or for batch testing. Where batch testing is permitted, a test unit shall consist of materials of the same product form, from the same heat, in the same condition of supply and with a total mass not exceeding limits given in B to E. 702 For testing of individual pieces, a piece shall be regarded as the rolled product from a single slab or billet, or from a single ingot if this is rolled directly into plates, strip, sections or bars.703 Except as required in 704, one set of mechanical tests is required for each test unit. A set of tests shall consist of one tensile test piece and, when required, three Charpy V-notch test pieces. See also E for testing of through thickness properties.704 Additional sets of tests shall be made for every variation of 10 mm in the thickness or diameter of products from the same test unit.A 800Mechanical properties801 The material shall meet the mechanical properties specified in B to E.802 If the results do not meet the specified requirements, the re-test procedures in Ch.1 may be adopted. Where the products are submitted to heat treatment or re-heat treatment, all the tests previously performed shall be repeated and the results must meet the specified requirements.A 900Inspection and tolerances901 Surface inspection and verification of dimensions are the responsibility of the manufacturer. Acceptance by the surveyor of material later found to be defective shall not absolve the manufacturer from this responsibility.902 Products shall have a workmanlike finish consistent with the method of manufacture and shall be free from cracks, shells and seams. Acceptance criteria for other imperfections such as rolled-in scale, indentations and roll marks, which may occur under normal manufacturing conditions, shall be EN 10163 Class A or equivalent standard.903 For plates and wide flats, the minus tolerance on ordered nominal thickness shall not exceed 0.3 mm. The plus tolerance on nominal thickness and other dimensional tolerances shall comply with the requirements of a recognised standard. The tolerances on nominal thickness are not applicable to areas repaired by grinding. 904 For sections and bars, the dimensional tolerances shall comply with the requirements of a recognised standard.905 The thickness of plates and wide flats shall be measured at locations whose distance from a longitudinal or transverse edge of the piece (ref. A702) shall be at least 10 mm. At least 3 measuring points along a line at each side shall be made. Measurements shall be made by on-line automated methods or off-line manual methods. The number of pieces to be measured, number of measurement readings to be recorded, and spacing between any two consecutive measured readings shall be decided and implemented by the manufacturer and shall be generally based on sound statistical analysis requirements.906 Thickness measurement data for plates and wide flats shall be analysed to assess that the readings are within permissible tolerance limits and the computed mean value shall be equal to or greater than ordered nominal thickness.907 The manufacturer shall maintain records of inspections and dimensional measurements. The records shall be presented to the surveyor on request.A 1000Repair1001 Surface defects may be removed by local grinding provided that:—the thickness is in no place reduced by more than 7% of the nominal thickness, but in no case by more than3 mm,—each single ground area does not exceed 0.25 m2,—the total area of local grinding does not exceed 2% of the total surface area,—the ground areas have smooth transitions to the surrounding surface.Ground areas lying in a distance less than their average width to each other shall be regarded as one single area. 1002 Surface defects which cannot be dealt with as in 1001 may be repaired by chipping or grinding followed by welding, subject to the surveyor's consent and under his supervision, provided that:—after removal of defects and before welding, the thickness of the product is in no place reduced by more than 20% of the nominal thickness,—welding is carried out by qualified welders using qualified procedures—the welding procedure is qualified using the requirements for butt welds according to Pt.2 Ch.3 Sec.5,—each single weld does not exceed 0.125 m2,—the total area of welding does not exceed 2% of the surface area of the side involved,—the distance between any two welds is not less than their average width,—the welds are made with an excess layer of beads and then ground flush with the product surface,—when deemed necessary, the repaired product is normalised or otherwise suitably post-weld heat treated,—the weld repairs are subjected to suitable non-destructive testing.1003 The manufacturer shall maintain records of repairs and subsequent inspections traceable to each product repaired. The records shall be presented to the surveyor on request.A 1100Identification1101 Every finished product shall be clearly marked by the manufacturer in at least one place with the Society's brand and the following particulars:a)manufacturer’s name or trade mark,b)steel grade, e.g. NV E36. When products comply with the requirements of E, the grade shall include thesuffix Z25 or Z35, e.g. NV E36Z25,c)identification number, heat number or other marking which will enable the full history of the product to betraced,d)if required by the purchaser, his order number or other identification mark.1102 The particulars in 1101, but excluding the manufacturer's name or trade mark where this is embossed on finished products, shall be encircled with paint or otherwise marked so as to be easily recognisable.1103 Where a number of products are securely fastened together in bundles, the manufacturer may brand only the top product of each bundle or, alternatively, a firmly fastened durable label containing the identification may be attached to each bundle.A 1200Certification1201 The manufacturer shall provide the type of inspection certificate required in the relevant construction rules giving the following particulars for each test unit which has been accepted:a)purchaser’s name, order number and, if known, the vessel identification,b)manufacturer’s name,c)description of products and steel grade,d)identification marking of products,e)steel making process, heat number and chemical composition,f)condition of supply,g)results of mechanical tests,h)when products comply with the requirements of E, the results of through thickness tensile tests andultrasonic tests,i)results of any supplementary and additional test requirements specified.1202 Before the inspection certificates or, pending final certification, shipping statements are signed by the surveyor, the manufacturer is required to provide a written declaration stating that the material has been made by an approved process and that it has been subjected to and has withstood satisfactorily the required tests. The following form of declaration will be accepted if stamped or printed on each inspection certificate or shipping statement with the name of the manufacturer and signed by an authorized representative of the manufacturer: “We hereby certify that the material has been made by an approved process and has been satisfactorily tested in accordance with DNV Rules for Classification.”1203 When steel is not produced at the works at which it is rolled, a certificate shall be supplied by the steelmaker stating the process of manufacture, the heat number and the chemical composition.B. Normal Strength SteelB 100Scope101 These requirements are supplementary to A and apply to normal strength steel. Provision is made for four grades based on the specified impact toughness and with specified minimum yield stress 235 MPa.。
DNV-rp-f301
RECOMMENDED PRACTICED ET N ORSKE VERITASDNV-RP-F301SUBSEA SEPARATOR STRUCTURAL DESIGNAPRIL 2007Comments may be sent by e-mail to rules@For subscription orders or information about subscription terms, please use distribution@Comprehensive information about DNV services, research and publications can be found at http :// , or can be obtained from DNV, Veritas-veien 1, NO-1322 Høvik, Norway; Tel +47 67 57 99 00, Fax +47 67 57 99 11.© Det Norske Veritas. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including pho-tocopying and recording, without the prior written consent of Det Norske puter Typesetting (FM+SGML) by Det Norske Veritas.Printed in NorwayIf any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compen-sation shall never exceed USD 2 million.In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalf of Det Norske Veritas.FOREWORDDET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life, prop-erty and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification and consultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, and carries out research in relation to these functions.DNV Offshore Codes consist of a three level hierarchy of documents:—Offshore Service Specifications. Provide principles and procedures of DNV classification, certification, verification and con-sultancy services.—Offshore Standards. Provide technical provisions and acceptance criteria for general use by the offshore industry as well asthe technical basis for DNV offshore services.—Recommended Practices. Provide proven technology and sound engineering practice as well as guidance for the higher levelOffshore Service Specifications and Offshore Standards.DNV Offshore Codes are offered within the following areas:A)Qualification, Quality and Safety Methodology B)Materials Technology C)Structures D)SystemsE)Special Facilities F)Pipelines and Risers G)Asset Operation H)Marine Operations J)Wind TurbinesAmendments and CorrectionsThis document is valid until superseded by a new revision. Minor amendments and corrections will be published in a separate document normally updated twice per year (April and October).For a complete listing of the changes, see the “Amendments and Corrections” document located at: /technologyservices/, “Offshore Rules & Standards”, “Viewing Area”.The electronic web-versions of the DNV Offshore Codes will be regularly updated to include these amendments and corrections.Recommended Practice DNV-RP-F301, April 2007Introduction – Page 3IntroductionThis Recommended Practice (RP) provides general require-ments for the design-, manufacture-, testing and certification processes for subsea gravity separators intended used for deep-water applications. In this context deepwater may be defined as water depths where the governing load is the external, rather than the internal pressure.The objectives of this document are:—to provide an internationally acceptable standard for the structural integrity of Subsea Separators —to provide more exact design criteria when the external pressure is governing for required thicknesses of the design—to serve as a technical reference document in contractual matters—to serve as a guideline for the designers, suppliers, pur-chasers and regulators reflecting 'state-of-the art' as well as consensus on accepted industry practice—to specify procedures and requirements for certification (or classification) of Subsea Separators intended used on deepwater installations.D ET N ORSKE V ERITASRecommended Practice DNV-RP-F301, April 2007Page 4 – IntroductionD ET N ORSKE V ERITASRecommended Practice DNV-RP-F301, April 2007Contents – Page 5 CONTENTS1.GENERAL (7)1.1General (7)1.1.1Introduction (7)1.1.2Objectives (7)1.1.3Application and scope (7)1.1.4PED, particular compliance issues (7)1.2How to use the RP (7)1.2.1Users of the RP (7)1.2.2Structure of this RP (7)1.3Normative references (8)1.3.1Offshore Standards (8)1.3.2Recommended Practices (8)1.3.3Other references (8)1.4Definitions (9)1.5Abbreviations and symbols (9)2.DESIGN PHILOSOPHY (10)2.1General (10)2.1.1Objective (10)2.1.2Applicability (10)2.2Safety philosophy (10)2.2.1Safety objective (10)2.2.2Systematic review (10)2.2.3Fundamental requirements (10)2.2.4Installation and operational considerations (11)2.2.5Design principles (11)2.2.6Quality assurance (11)2.3Design format (11)2.3.1Basic considerations (11)2.3.2Safety class methodology (12)2.3.3Design by LRFD-method (12)2.3.4Working Stress Design (WSD) (12)2.3.5Reliability based design (12)2.4Safety Class Concept and PED (13)3.DESIGN (14)3.1General (14)3.2Material selection (14)3.3Loads and load effects (14)3.4Resistance (14)3.5Limit states and failure modes (14)3.6Calculation methods (14)3.7Design criteria (14)3.7.1General (14)3.7.2Guidance for EN 13445-3, Annex B (15)3.8Design details (16)4.MATERIALS (16)4.1Application (16)4.2Normative references (16)4.3General requirements (16)4.3.1Type of materials (16)4.3.2C-Mn steel with SMYS > 555 MPa (16)4.3.3Corrosion (16)4.4Material manufacturing (16)4.4.1Manufacturing Procedure Specification (MPS) (16)4.4.2General requirements (16)4.5Material requirements (17)4.5.1Steelmaking (17)4.5.2Chemical composition (17)4.5.3Mechanical properties (17)4.6Material testing......................................................194.6.1Chemical analysis. (19)4.6.2Mechanical testing (19)4.6.3Hardness test (19)4.6.4SSC test (19)4.6.5Pitting corrosion testing (20)4.6.6Metallographic examination (20)4.6.7Re-testing (20)4.7Non-destructive testing and workmanship (20)4.7.1General (20)4.7.2Visual examination and workmanship (20)4.7.3Ultrasonic examination (20)4.7.4Repair of defects (20)4.8Material certification (20)5.FABRICATION, TESTING ANDINSPECTION OF CLAD STEEL PLATES (20)5.1Application (20)5.2Normative references (20)5.3Manufacturing of clad steel materials (20)5.3.1Manufacturing Procedure Specification (MPS) (20)5.3.2General requirements (20)5.3.3Qualification of cladding procedure (20)5.4Fabrication testing (20)5.4.1General (20)5.4.2Tensile test (21)5.4.3Impact testing (21)5.4.4Hardness testing (21)5.4.5Metallographic examination (21)5.4.6Bend tests of cladding (21)5.4.7Shear strength of cladding (21)5.4.8Pitting corrosion test (21)5.4.9Re-testing (21)5.5Non-destructive testing and workmanship (21)5.5.1General (21)5.5.2Inspection and tolerances (21)5.5.3Surface crack examination (21)5.5.4Ultrasonic examination (21)5.5.5Repair of defects (21)5.5.6Personnel qualifications (22)5.6Inspection document (22)6.FABRICATION, TESTINGAND INSPECTION OF SEPARATOR (22)6.1Application (22)6.2Normative references (22)6.3Resistance to external corrosion and HISC (22)6.4Manufacture of separator (22)6.4.1Manufacturing Procedure Specification for separatorfabrication (MPS) (22)6.4.2Manufacturing Procedure Qualification Test for separatorfabrication (MPQT) (23)6.4.3Plate forming (23)6.4.4Welding (23)6.4.5Heat treatment (23)6.5Non-destructive testing (23)6.5.1General (23)6.5.2Visual inspection (23)6.5.3Magnetic particle inspection and ultrasonic examination23 6.5.4Correction of defects (23)6.5.5Personnel qualifications (23)6.6Fabrication testing (24)6.6.1General (24)6.6.2Type of tests (24)6.6.3Sampling and extent of fabrication tests (25)6.7Dimensions (25)6.8Pressure testing (26)D ET N ORSKE V ERITASRecommended Practice DNV-RP-F301, April 2007 Page 6 – Contents6.8.1External over-pressure (26)6.8.2Internal over-pressure (26)6.8.3Conclusion – pressure testing (26)6.9Inspection documents (26)7.CERTIFICATION PROCESS (26)7.1Introduction (26)7.2Certification procedures (26)7.3Documentation requirements ..............................278.OPERATION, MAINTENANCEAND PERIODIC INSPECTION (27)9.REFERENCES (28)9.1Codes and standards (28)9.2Papers and publications (28)APP. A SAFETY CLASS, CALIBRATION (29)APP. B DESIGN OF SUBSEA SEPARATOR ACCORDING TO EN 13445-3 ANNEX B (31)D ET N ORSKE V ERITASPage 71. General1.1 General1.1.1 IntroductionThis Recommended Practice (RP) provides general require-ments for the design, manufacture, testing and certification processes for subsea gravity separators intended used for deep-water applications. In this context deepwater may be defied as water depths where the governing load is the external rather than the internal pressure.This document provides recommended practice to achieve an acceptable overall safety level regarding the structural strength of the separators.This RP has been developed for general world-wide applica-tion. Governmental legislation may include requirement in excess of the provisions of this standard depending on the intended installation.Extracts from the requirement in the EU Directive Pressure Equipment, PED, EU Council Directive No. 97/23/EC are partly included, which need to be considered on subsea sepa-rators to be installed on one of the Continental Shelves within the EEA (European Economic Area).The functionality of the separator is not covered by this Rec-ommended Practice.The main benefits of using this RP comprise:—provision of subsea separator solutions for deepwater applications that are safe and feasible for construction —specific guidance and requirements for efficient design analysis based on EN 13445, that satisfy the Pressure Equipment Directive (Applicable within EEA)—application of a risk based approach where the magnitudes of the safety factors depend on consequence of failure (safety class methodology).1.1.2 ObjectivesThis objective of this document is to:—provide an internationally acceptable RP for the structural integrity of subsea separators—provide more exact design criteria when external pressure is governing for the required thicknesses—serve as a technical reference document in contractual matters—serve as a guideline for designers, suppliers, purchasers and regulators reflecting state-of-the art and consensus on accepted industry practice—specify procedures and requirements for certification or classification of Subsea separators intended used on deep-water installations.1.1.3 Application and scopeThis standard applies primarily to subsea production separa-tors at deepwater installations within the petroleum and natural gas industries. At more ordinary water depths, existing prac-tice, e.g. using the design by formulae (DBF) methodology in EN 13445-3, may provide feasible solutions. For deep water locations the design by analysis (DBA) approach provides consistent means to achieve more optimal designs with accept-able reliability. The design philosophy as focused on in this RP may also be utilised for ordinary water depths. Connecting piping, foundation, anchoring and skids used for transportation, installation, etc. is considered outside the scope for this standard.For others applications, special considerations may need to be agreed with the parties involved and according to the statutory regulations.1.1.4 PED, particular compliance issuesThis RP is essentially based on application of EN 13445, which is a harmonised standard and gives presumption of con-formity with PED. However, this RP covers designs that were not in focus when PED was developed. In particular two issues have been addressed in this RP where PED does not provide a clear guidance, and additional considerations have been made in order to ensure that the essential safety requirements (Annex I of PED) are met. These issues relate to:—application of safety class methodology—proof test (pressure testing).This RP provide explicit guidance on these issues as further described in Subsection 2.4 and in 6.8 respectively. Clarifica-tion of these issues may be of common interest within EU. Questions together with proposed answers (as reflected in these subsections) have been formulated and will be sent to the National Authorities for potential further processing in EU. A possible outcome is that this may end up as guidelines to PED.1.2 How to use the RP1.2.1 Users of the RPThe client (or purchaser) is understood to be the party ulti-mately responsible for the system as installed and its indented use in accordance with the prevailing laws, statutory rules and regulations.The contractor is understood to be the party contracted by the client to perform all or part of the necessary work required to bring the system to an installed and operable condition.The designer is understood to be the party contracted by the contractor to fulfil all or part of the activities associated with the design, and provides the main contribution to the design verification report.The manufacturer is understood to be the party contracted by the contractor to manufacture all of part of the system.The certification body is usually appointed by the client to per-form independent certification.1.2.2 Structure of this RPThe documents is organised as illustrated in the flowchart in Figure 1-1.Section 1 contains the objectives and scope of the Recom-mended Practice. It further introduces essential concepts, def-initions and abbreviations.Section 2 provides the design philosophy which includes the safety philosophy and design format. In particular the concept of safety class is given and discussed in relationship to PED and the fully harmonised standard EN 13445.Section 3 deals with the design criteria. Here the relevant load effects and material properties to be applied in the analysis are given together with a detailed description on how to carry out the design analysis.Section 4 covers requirements to the base material, and coves aspects of manufacturing, chemical composition, properties, testing and resistance towards corrosion and Hydrogen Induced Stress Cracking (HISC) with particular focus on important parameters regarding use of clad and duplex steel and for the manufacturing of thick plates.Section 5 contains requirements for the fabrication, testing and inspection of clad and duplex steel plates, whereas Section 6 covers such requirements for the separator.Section 7 gives the certification process in terms of certifica-tion activities to be carried out by the certification body during design and fabrication. It also includes a list of documentation to be submitted by the manufacturer and designer for review and approval.D ET N ORSKE V ERITASPage 8Section 8 on operation, maintenance and inspection addresses important issues to be addressed in preceding activities since the vessel is likely “never to be seen again” once it is installed. Note that installation aspects are not covered by this RP.All users should go through Section 1 and 2 describing the scope of the RP and the design principles. The design analysis should be carried out by the designer according to Section 3, taking into account the design premises that are to be specified by the client and contractor. The contractor, manufacturer and certification body should consider Sections 5, 6 and 7, cover-ing fabrication and certification.Flow chart of RP1.3 Normative referencesThe following standards below include requirements that through reference in the text constitute provisions of this stand-ard. Last revision of the references shall be used unless other-wise agreed. Other recognised standards may be used provided it can be demonstrated that these meet or exceed the require-ments of the standards referred to herein and accepted by the involved parties as supplier, contractor, field operator, any third party or certifying authority/notified body.Any deviations, exceptions or modifications to the codes and standards shall be documented for agreement or approval need to be given by the parties involved.1.3.1 Offshore StandardsDNV-OS-F101, Submarine Pipeline Systems1.3.2 Recommended PracticesDNV-RP-B401, Cathodic Protection Design1.3.3 Other referencesISO/FDIS 2394 General Principles on Reliability of Structures PED, Pressure Equipment Directive, Directive 97/23/EC of the European Parliament and of the Council vessels”EN-13445-1, Unfired pressure vessels – Part 1: GeneralEN-13445-2, Unfired pressure vessels – Part 2: MaterialsEN-13445-3, Unfired pressure vessels – Part 3: DesignEN-13445-4, Unfired pressure vessels – Part 4: Fabrication EN-13445-5, Unfired pressure vessels – Part 5: Inspection andtestingISO 15156-1, Petroleum and natural gas industries – Materials for use in H2S-containing environments in oil and gas produc-tion – Part1: General principles for selection of cracking resist-ant materialsISO 15156-2, Petroleum and natural gas industries – Materials for use in H2S-containing environments in oil and gas produc-tion – Part 2: Cracking resistant carbon and low alloy steels, and the use of cast iron.ISO 15156-3, Petroleum and natural gas industries – Materials for use in H2S-containing environments in oil and gas produc-tion – Part 3: Cracking resistant CRAs (corrosion resistant alloys) and other alloysEN 10028-1, Flat products made of steels for pressure pur-poses - Part 1: General requirements.EN 10028-6, Flat products made of steels for pressure pur-poses - Part 6: Weldable fine grain steels, quenched and tem-pered.D ET N ORSKE V ERITASPage 9EN 288-3:1992+A1, Specification and approval of welding procedures for metallic materials –Part 3: Welding procedure tests for the arc welding of steels (Amendment A1:1997 included).EN 1043-1, Destructive tests on welds in metallic materials. Hardness testing – Part 1: Hardness test on arc welded joints.1.4 DefinitionsClad component: component with internal liner where the bond between base and cladding material is metallurgical. This includes corrosion resistant layer applied by weld overlay, hot rolling and explosion bonded plates.Corrosion allowance: The amount of thickness added to the thickness of the component to allow for corrosion/erosion/ wear.Deepwater separator: Subsea separators for deepwater appli-cations. In this context deepwater may be defined as water depths where the governing load is the external rather than the internal pressure.Environmental loads: Loads due to the environment, such as waves and current, wind.Failure: An event causing an undesirable condition, e.g. loss of component or system function, or deterioration of functional capability to such an extent that the safety of the unit, person-nel or environment is significantly reduced.Fatigue: Cyclic loading causing degradation of the material. Fatigue Limit State (FLS): Related to the possibility of failure due to the effect of cyclic loading.Fracture Analysis: Analysis where critical initial defect sizes under design loads are identified to determine the crack growth life to failure, i.e. leak or unstable fracture.Inspection: Activities such as measuring, examination, testing, gauging one or more characteristics of an object or service and comparing the results with specified requirements to determine conformity.Installation: The operation related to installing the separator, including tie-in.Limit State: The state beyond which the separator or part of the separator no longer satisfies the requirements laid down to its performance or operation. Examples are structural failure or operational limitations.Load: The term load refers to physical influences which cause for example stress, strain or deformation in the separator. Load Effect: Response or effect of a single load or combination of loads on the structure, such as stress, strain and deformation. Load and Resistance Factor Design (LRFD): Design format based upon a limit state and partial safety factor methodology. The partial safety factor methodology is an approach where separate factors are applied for each load effect (response) and resistance term.Location class: A geographic area classified according to the distance from locations with regular human activities.Lot: A number of plates from the same heat, the same heat treatment batch and with the same thickness.Non-destructive testing (NDT): Structural tests and inspection of welds or parent material with radiography, ultrasonic, mag-netic particle or eddy current testing.Offshore Standard (OS): Offshore Standard: The DNV off-shore standards are documents which presents the principles and technical requirements for design of offshore structures. The standards are offered as DNV’s interpretation of engineer-ing practice for general use by the offshore industry for achiev-ing safe structures.Operation, Normal Operation: Conditions that are part of rou-tine (normal) operation of the separator.Out of roundness: The deviation of the perimeter from a circle. This can be an ovalisation, i.e. an elliptic cross section, or a local out of roundness, e.g. flattening. The numerical defini-tion of out of roundness and ovalisation is the same. Ovalisation: The deviation of the perimeter from a circle resulting in an elliptic cross section.Prior Service Life: The duration that a component has been in service, since its installation. Duration is computed from the time of installation or production if relevant. Recommended Practice (RP): The publications cover proven technology and solutions which have been found by DNV to represent good practice.Residual Service Life: The duration that a component will be in service, from this point forward in time (from now). Dura-tion is computed from now until the component is taken out of service.Safety Class: A concept adopted herein to classify the criticality of the subsea separator with respect to consequence of failure. Safety Class Resistance Factor: Partial safety factor which transforms the lower fractile resistance to a design resistance reflecting the safety class.Service Life: The length of time assumed in design that a com-ponent will be in service.Uncertainty: In general the uncertainty can be described by a probability distribution function. In the context of this Recom-mended Practice, the probability distribution function is described in terms of bias and standard deviation of the varia-ble.1.5 Abbreviations and symbolsAbbreviationsALS Accidental Limit StateAPI American Petroleum InstituteCOV Coefficient Of VarianceCRA Corrosion Resistant AlloyDBA Design By AnalysisDBF Design By FormulaeDNV Det Norske VeritasEEA European Economic AreaFEM Finite Element MethodFLS Fatigue Limit StateHPIC Hydrogen Pressure Induced CrackingLRFD Load and Resistance Factor DesignNDE Non-Destructive ExaminationNDP Norwegian Deepwater ProgramNDT Non-Destructive TestingPED Pressure Equipment Directive (applicable within EEA)PWHT Post Weld Heat TreatmentRP Recommended PracticeSLS Serviceability Limit StateSSC Stress Sulphide CrackingTRB Three roll bending3D Three-dimensionalUO Fabrication process for welded pipesUOE Pipe fabrication process for welded pipes,expandedWSD Working Stress DesignD ET N ORSKE V ERITASPage 10SymbolsGreek Characters2. Design Philosophy2.1 General2.1.1 ObjectiveThe purpose of this section is to present the safety philosophy and corresponding limit state design format applied in this RP.2.1.2 ApplicabilityThis section applies to subsea separators that are to be built in accordance with this RP. Note that the focus for this RP is the overall structural integrity of subsea separators in deep water where the static external pressure is the governing load condi-tion. No design practice has yet been established for such con-ditions. At more shallow water depths, existing design practice governed by external overpressure according to existing rules and regulations applies, where also the design by analysis approach as described here may be an attractive and applicable option.2.2 Safety philosophyThe integrity of a subsea separator in deep water constructed to this standard is ensured through a safety philosophy integrat-ing the different aspects illustrated in Figure 2-1.Safety hierarchy 2.2.1 Safety objectiveAn overall safety shall be established, planned and imple-mented by company covering all phases from conceptual development until retrieval or abandonment.Guidance note:All companies have policy regarding human aspects, environ-mental and financial issues. These are typically on an overall level, but more detailed objectives and requirements in specific areas may follow them. Typical statements regarding safety objectives for a subsea separator may be:All work during the construction period shall be such as to ensure that no single failure will lead to dangerous situations for any person or to unacceptable damage to material or the environ-ment.The impact on the environment shall be reduced to as low as rea-sonably possible.Statements such as those above may have implications for all or individual phases only. They are typically most relevant for the work execution (i.e. how the contractor executes the job) and for specific design solutions. Having defined the Safety Objective, it can be a point of discussion as to whether this is being accom-plished in the actual project. It is therefore recommended that the overall Safety Objective be followed up by more specific, meas-urable requirements.If no policy is available, or if it is difficult to define the safety objective, one could also start with a risk assessment. The risk assessment could identify all hazards and their consequences, and then enable back-extrapolation to define acceptance criteria, testing regime and areas that need to be followed up more closely.In this Recommended Practice, the structural failure probability is reflected in the choice of safety class. The choice of safety class should also include consideration of the expressed safety objective.---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---2.2.2 Systematic reviewA systematic review or analysis shall be carried out at all phases in order to identify and evaluate the consequences of failure of the subsea separator, such that necessary remedial measures can be taken. The consequences include conse-quences of such events for people, for the environment and for assets and financial interests.Guidance note:A methodology for such a systematic review is quantitative riskanalysis (QRA). This may provide an estimation of the overall risk to human health and safety, environment and asses and com-prises:-hazard identification-assessment of probabilities of failure events-accident developments-consequence and risk assessment.It should be noted that legislation in some countries requires risk analysis to be performed, at least at an overall level to identify critical scenarios that might jeopardise the safety and reliability of the separator system. Other methodologies for identification of potential hazards are Failure Mode and Effect Analysis (FMEA) and Hazard and Operability studies (HAZOP).---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---2.2.3 Fundamental requirementsA separator shall be designed, manufactured, fabricated, oper-ated and maintained in such a way that:—with acceptable probability, it will remain fit for the use for which it is intended, having due regard to its service life and its cost, and—with appropriate degree of reliability, it will sustain all foreseeable load effects, degradation and other influences likely to occur during the service life and have adequate durability in relation to maintenance costs.E Elastic modulusID Inner diameterMD Mid plane diameterOD Outer diameterP f Failure probabilities (annual)t corr Corrosionallowancet nom Nominal (specified) wall thicknesst ref ReferencethicknessT Time in yearsT design Design life time in yearsγSafety factor (SF)γSC Safety class factor accounting for the failureconsequenceρFluid (water) densityσStandard deviation; Nominal stressD ET N ORSKE V ERITAS。
dnv-rp-b401_2011-04Cathodic Protection Design
RECOMMENDED PRACTICED ET N ORSKE VERITASDNV-RP-B401CATHODIC PROTECTION DESIGNOCTOBER 2010This document has been amended since the main revision (October 2010), most recently in April 2011.See “Changes” on page 3.The electronic pdf version of this document found through is the officially binding version © Det Norske VeritasAny comments may be sent by e-mail to rules@For subscription orders or information about subscription terms, please use distribution@ Computer Typesetting (Adobe Frame Maker) by Det Norske VeritasThis service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document, and is believed to reflect the best of contemporary technology. The use of this document by others than DNV is at the user's sole risk. DNV does not accept any liability or responsibility for loss or damages resulting from any use of this document.FOREWORDDET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life,property and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification and consultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, and carries out research in relation to these functions.DNV service documents consist of amongst other the following types of documents:—Service Specifications. Procedual requirements.—Standards. Technical requirements.—Recommended Practices. Guidance.The Standards and Recommended Practices are offered within the following areas:A)Qualification, Quality and Safety Methodology B)Materials Technology C)Structures D)SystemsE)Special Facilities F)Pipelines and Risers G)Asset Operation H)Marine Operations J)Cleaner EnergyO)Subsea SystemsAmended April 2011Recommended Practice DNV-RP-B401, October 2010 see note on front cover Changes – Page 3 CHANGES•GeneralAs of October 2010 all DNV service documents are primarily published electronically.In order to ensure a practical transition from the “print” scheme to the “electronic” scheme, all documents having incorporated amendments and corrections more recent than the date of the latest printed issue, have been given the date October 2010.An overview of DNV service documents, their update status and historical “amendments and corrections” may be found through /resources/rules_standards/.•Main changes October 2010Since the previous edition (January 2005), this document has been amended, most recently in April 2008. All changes have been incorporated and a new date (October 2010) has been given as explained under “General”.•Amendments April 2011—Item 6.5.2 has been amended and clarified concerning galvanic anode performance requirements.—A new Guidance note has been added to item 12.4.4 (Annex C).—The layout has been changed to one column in order to improve electronic readability.Recommended Practice DNV-RP-B401, October 2010Amended April 2011 Page 4 – Contents see note on front coverCONTENTS1.GENERAL (6)1.1Introduction (6)1.2Scope (6)1.3Objectives and Use (7)1.4Document Structure (7)1.5Relation to Other DNV Documents (7)2.REFERENCES (7)2.1General (7)2.2ASTM (American Society for Testing and Materials) (7)2.3DNV (Det Norske Veritas) (7)2.4EN (European Standards) (7)2.5NORSOK (7)2.6ISO (International Organization for Standardisation) (7)2.7NACE International (8)3.TERMINOLOGY AND DEFINITIONS (8)3.1Terminology (8)3.2Definitions (8)4.ABBREVIATIONS AND SYMBOLS (9)4.1Abbreviations (9)4.2Symbols (9)5.GENERAL CP DESIGN CONSIDERATIONS (INFORMATIVE) (10)5.1General (10)5.2Limitations of CP (10)5.3Environmental Parameters Affecting CP (10)5.4Protective Potentials (11)5.5Detrimental effects of CP (11)5.6Galvanic Anode Materials (12)5.7Anode Geometry and Fastening Devices (13)5.8Use of Coatings in Combination with CP (13)5.9Electrical Continuity and Current Drain (13)6.CP DESIGN PARAMETERS (14)6.1General (14)6.2Design Life (14)6.3Design Current Densities (14)6.4Coating Breakdown Factors for CP Design (16)6.5Galvanic Anode Material Design Parameters (17)6.6Anode Resistance Formulas (18)6.7Seawater and Sediment Resistivity (18)6.8Anode Utilization Factor (18)6.9Current Drain Design Parameters (18)7.CP CALCULATION AND DESIGN PROCEDURES (19)7.1General (19)7.2Subdivision of CP Object (20)7.3Surface Area Calculations (20)Amended April 2011Recommended Practice DNV-RP-B401, October 2010 see note on front cover Contents – Page 57.4Current Demand Calculations (20)7.5Current Drain Calculations (20)7.6Selection of Anode Type (21)7.7Anode Mass Calculations (21)7.8Calculation of Number of Anodes (21)7.9Calculation of Anode Resistance (22)7.10Anode Design (23)7.11Distribution of Anodes (23)7.12Provisions for Electrical Continuity (23)7.13Documentation (24)8.ANODE MANUFACTURE (24)8.1General (24)8.2Manufacturing Procedure Specification (25)8.3Pre-Production Qualification Testing (25)8.4Quality Control of Production (26)8.5Materials, Fabrication of Anode Inserts and Casting of Anodes (26)8.6Inspection and Testing of Anodes (27)8.7Documentation and Marking (28)8.8Handling, Storage and Shipping of Anodes (28)9.INSTALLATION OF ANODES (28)9.1General (28)9.2Installation Procedure Specification (28)9.3Qualification of installation (29)9.4Receipt and Handling of Anodes (29)9.5Anode Installation and Provisions for Electrical Continuity (29)9.6Inspection of Anode Installation (29)9.7Documentation (29)10.ANNEX A – TABLES AND FIGURES (30)10.1Tables and Figures (30)11.ANNEX B – LABORATORY TESTING OF GALVANIC ANODE MATERIALSFOR QUALITY CONTROL (33)11.1General (33)11.2Sampling and Preparation of Test Specimens (33)11.3Equipment and Experimental Procedure (33)11.4Acceptance Criteria and Re-Testing (34)11.5Documentation (34)12.ANNEX C – LABORATORY TESTING OF GALVANIC ANODE MATERIALSFOR QUALIFICATION OF ELECTROCHEMICAL PERFORMANCE (36)12.1General (36)12.2Sampling and Preparation of Test Specimens (36)12.3Equipment and Experimental Procedure (36)12.4Documentation (37)Recommended Practice DNV-RP-B401, October 2010Amended April 2011 Page 6 – 1. General see note on front cover1. General1.1 Introduction1.1.1 ‘Cathodic protection’ (CP) can be defined as e.g. “electrochemical protection by decreasing the corrosion potential to a level at which the corrosion rate of the metal is significantly reduced” (ISO 8044) or “a technique to reduce corrosion of a metal surface by making that surface the cathode of an electrochemical cell”(NACE RP0176). The process of suppressing the corrosion potential to a more negative potential is referred to as ‘cathodic polarization’.1.1.2 For galvanic anode CP systems, the anode of the electrochemical cell is a casting of an electrochemically active alloy (normally aluminium, zinc or magnesium based). This anode is also the current source for the CP system and will be consumed. Accordingly, it is often referred to as a ‘sacrificial anode’, as alternative to the term ‘galvanic anode’ consistently used in this Recommended Practice (RP). For ‘impressed current’ CP, an inert (non-consuming) anode is used and the current is supplied by a rectifier. In this RP, the cathode of the electrochemical cell (i.e. the structure, sub-system or component to receive CP) is referred to as the ‘protection object’.1.1.3 For permanently installed offshore structures, galvanic anodes are usually preferred. The design is simple, the system is mechanically robust and no external current source is needed. In addition, inspection and maintenance during operation can largely be limited to periodic visual inspection of anode consumption and absence of visual corrosive degradation. However, due to weight and drag forces caused by galvanic anodes, impressed current CP systems are sometimes chosen for permanently installed floating structures.1.1.4 CP is applicable for all types of metals and alloys commonly used for subsea applications. It prevents localised forms of corrosion as well as uniform corrosion attack, and eliminates the possibility for galvanic corrosion when metallic materials with different electrochemical characteristics are combined. However, CP may have certain detrimental effects, for example hydrogen related cracking of certain high-strength alloys and coating disbondment as described in 5.5.1.1.5 CP is primarily intended for metal surfaces permanently exposed to seawater or marine sediments. Still, CP is often fully effective in preventing any severe corrosion in a tidal zone and has a corrosion reducing effect on surfaces intermittently wetted by seawater.1.2 Scope1.2.1 This RP has been prepared to facilitate the execution of conceptual and detailed CP design using aluminium or zinc based galvanic anodes, and specification of manufacture and installation of such anodes. Whilst the requirements and recommendations are general, this document contains advice on how amendments can be made to include project specific requirements. The RP can also easily be amended to include requirements or guidelines by a regulating authority, or to reflect Owner’s general philosophy on corrosion control by CP.1.2.2 Some of the design recommendations and methods in Sections 5, 6 and 7 are also valid for CP systems using other current sources such as magnesium anodes and rectifiers (i.e. impressed current).1.2.3 This RP is primarily intended for CP of permanently installed offshore structures associated with the production of oil and gas. Mobile installations for oil and gas production like semi-submersibles, jack-ups and mono-hull vessels are not included in the scope of this document. However, to the discretion of the user, relevant parts of this RP may be used for galvanic anode CP of such structures as well.1.2.4 Detailed design of anode fastening devices for structural integrity is not included in the scope of this RP. Considerations related to safety and environmental hazards associated with galvanic anode manufacture and installation are also beyond its scope.1.2.5 Compared to the 1993 edition of DNV-RP-B401, design considerations for impressed current CP have been deleted from the scope of the 2004 revision whilst the sections on anode manufacture and installation are made more comprehensive. CP of submarine pipelines is further excluded from the scope (see 1.5). However, this RP is applicable for CP of components of a pipeline system installed on template manifolds, riser bases and other subsea structures when such components are electrically connected to major surfaces of structural C-steel.In this revision, guidance and explanatory notes are contained in a ‘Guidance note’ to the applicable paragraph in Sections 6, 7, 8 and in Annex B and C. (Most of the Guidance notes are based on queries on the 1993 revision of DNV-RP-B401 and other experience from its use. Furthermore, some informative text in the old revision has been contained in such notes).All tables and figures associated with Sec.6 are contained in Annex A. The document has further been revised to facilitate specification of Purchaser information to Contractor, and optional requirements associated with CP design, manufacture and installation of anodes (see 1.3). Additional comments on revisions in this 2004 issue are made in the Introduction (last paragraph) of Sections 6, 7, 8 and Annex B and C.Amended April 2011Recommended Practice DNV-RP-B401, October 2010see note on front cover 2. References – Page 71.3 Objectives and Use1.3.1 This RP has two major objectives. It may be used as a guideline to Owner’s or their contractors’execution of conceptual or detailed CP design, and to the specification of galvanic anode manufacture and installation. It may also be used as an attachment to an inquiry or purchase order specification for such work.If Purchaser has chosen to refer to this RP in a purchase document, then Contractor shall consider all requirements in Sections 6-9 of this document as mandatory, unless superseded by amendments and deviations in the specific contract. Referring to this document in a purchase document, reference shall also be made to the activities for which DNV-RP-B401 shall apply, i.e. CP design in Sections 6 and 7, anode manufacture in Sec.8and/or anode installation in Sec.9.1.3.2 CP design, anode manufacture and anode installation are typically carried out by three different parties (all referred to as ‘Contractor’). Different parties issuing a contract (i.e. ‘Purchaser’) may also apply. The latter includes ‘Owner’, e.g. for CP design and qualification of galvanic anode materials. For definition of contracting parties and associated terminology, see Sec.3.1.3.3 Specification of project specific information and optional requirements for CP detailed design, anode manufacture and anode installation are described in 7.1.2, 8.1.2 and 9.1.3, respectively.1.4 Document Structure1.4.1 Guidelines and requirements associated with conceptual and detailed CP design are contained in Sections 5, 6 and 7, whilst galvanic anode manufacture and installation are covered in Sec.8 and Sec.9,respectively. Tabulated data for CP design are compiled in Annex A. Annex B and C contain recommended procedures for laboratory testing of anode materials for production quality control and for documentation of long-term electrochemical performance, respectively.1.5 Relation to Other DNV Documents1.5.1 Cathodic protection of submarine pipelines is covered in DNV-RP-F103.2. References2.1 GeneralThe following standards (2.2-2.7) are referred to in this RP. The latest editions apply.2.2 ASTM (American Society for Testing and Materials)2.3 DNV (Det Norske Veritas)2.4 EN (European Standards)2.5 NORSOK2.6 ISO (International Organization for Standardisation)ASTM G8Test Method for Cathodic Disbonding of Pipeline Coating ASTM D1141Specification for Substitute Ocean SeawaterDNV-RP-F103Cathodic Protection of Submarine Pipelines by Galvanic AnodesEN 10204Metallic Products – Types of Inspection DocumentsNORSOK M-501Standard for Surface Preparation and Protective CoatingISO 3506Mechanical Properties of Corrosion-Resistant Stainless Steel Fasteners ISO 8044Corrosion of Metals and Alloys; Basic Terms and DefinitionsISO 8501-1Preparation of Steel Substrates for Application of Paint and Related Products – Visual Assessment of Surface Cleanliness.Part 1: Rust Grades and Preparation Grades of Uncoated Steel Substrates. ISO 10005Quality Management- Guidelines for Quality Plans ISO 10474Steel and Steel Products – Inspection DocumentsRecommended Practice DNV-RP-B401, October 2010Amended April 2011Page 8 – 3. Terminology and Definitions see note on front cover2.7 NACE International3. Terminology and Definitions3.1 Terminology3.2 DefinitionsFor the following technical items below, definitions in the text apply:cathodic protection (1.1.1), galvanic anode (1.1.2), protection object (1.1.2), polarization (1.1.1), calcareous scale/layer (5.5.13), cathodic disbondment (5.5.1).References within parentheses refer to the applicable paragraph.For items applicable to quality control and CP design parameters, reference to the applicable paragraph is made in the list of abbreviations (4.1) and symbols (4.2).NACE RP0176Corrosion Control of Steel Fixed Offshore Structures Associated with Petroleum ProductionNACE RP0387Metallurgical and Inspection Requirements for Cast Sacrificial Anodes for Offshore ApplicationsOwner Party legally responsible for design, construction and operation of the object to receive CP.Purchaser Party (Owner or main contractor) issuing inquiry or contract for CP design, anode manufacture or anode installation work, or nominated representative.Contractor Party to whom the work (i.e. CP design, anode manufacture or anode installation) has been contracted.shall indicates a mandatory requirement.should indicates a preferred course of action.mayindicates a permissible course of action.agreed/agreement refers to a written arrangement between Purchaser and Contractor (e.g. as stated in a contract).report and notify refers to an action by Contractor in writing.accepted acceptance refers to a confirmation by Purchaser in writing.certificate certified refers to the confirmation of specified properties issued by Contractor or supplier of metallic materials according to EN 10204:3.1.B, ISO 10474:5.1-B or equivalent.purchase document(s)refers to an inquiry/tender or purchase/contract specification, as relevant.Amended April 2011Recommended Practice DNV-RP-B401, October 2010 see note on front cover 4. Abbreviations and Symbols – Page 9 4. Abbreviations and Symbols4.1 AbbreviationsCP cathodic protectionCR concession request (8.5.6)CRA corrosion resistant alloyCTOD crack tip opening displacementDC direct currentDFT dry film thicknessHAZ heat affected zoneHISC hydrogen induced stress cracking (5.5.3)HV Vicker’s hardnessITP inspection and testing plan (8.4.2)IPS installation procedure specification (9.2)MIP manufacture and inspection plan (8.4.2)MPS manufacture procedure specification (8.2)NDT non-destructive testingPQT production qualification test (8.3)PWHT post weld heat treatment (5.5.7)ROV remotely operated vehicleRP recommended practiceSCE standard calomel electrode (6.1.5)SMYS specified minimum yield strengthUNS unified numbering systemWPS welding procedure specificationWPQT welding procedure qualification testYS yield strength4.2 SymbolsA (m²)anode surface area (Table 10-7)A c (m²)cathode surface area (7.4.1)a constant in coating breakdown factor (6.4.2)b constant in coating breakdown factor (6.4.2)C (Ah)current charge associated with quality control testing of anode materials (11.3.10)c (m)anode cross sectional periphery (Table 10-7)C a (Ah)(individual) anode current capacity (7.8.2)C a tot (Ah)total anode current capacity (7.8.2)E a° (V)design closed circuit anode potential (6.5.1)E c° (V)design protective potential (7.8.2)E'c (V)global protection potential (6.3.4)E'a (V)(actual) anode closed circuit potential (6.3.4)ΔE° (V)design driving voltage (7.8.2)ε (Ah/kg)anode electrochemical capacity (6.5.1)f c coating breakdown factor (6.4.1)f ci initial coating breakdown factor (6.4.4)f cm mean coating breakdown factor (6.4.4)f cf final coating breakdown factor (6.4.4)I a(A)(individual) anode current output (7.8.2)I ai (A)(individual) initial anode current output (7.8.2)I af (A)(individual) final anode current output (7.8.2)I a tot (A)total anode current output (6.3.4)I a tot i (A)total initial current output (7.8.4)Recommended Practice DNV-RP-B401, October 2010Amended April 2011Page 10 – 5. General CP Design Considerations (Informative)see note on front cover5. General CP Design Considerations (Informative)5.1 General5.1.1 This section addresses aspects of cathodic protection which are primarily relevant to CP conceptual design, including the compatibility of CP with metallic materials and coatings. The content of this section is informative in nature and intended as guidelines for Owners and their contractors preparing for conceptual or detailed CP design. Nothing in this section shall be considered as mandatory if this RP has been referred to in a purchase document.5.1.2 Compared to the 1993 revision of this RP, the major revisions of this 2004 revision are contained in 5.5.5.2 Limitations of CP5.2.1 For carbon and low-alloy steels, cathodic protection should be considered as a technique for corrosion control, rather than to provide immunity (1.1.1). It follows that cathodic protection is not an alternative to corrosion resistant alloys for components with very high dimensional tolerances, e.g. sealing assemblies associated with subsea production systems.5.3 Environmental Parameters Affecting CP5.3.1 The major seawater parameters affecting CP in-situ are:—dissolved oxygen content —sea currents —temperature —marine growth —salinity.In addition, variations in seawater pH and carbonate content are considered factors which affect the formation of calcareous layers associated with CP and thus the current needed to achieve and to maintain CP of bare metal surfaces. In seabed sediments, the major parameters are: temperature, bacterial growth, salinity and sediment coarseness.I a tot f (A)total final current output (7.8.4)I c (A)current demand (7.4.2)I ci (A)initial current demand (7.4.2, 6.3.1)I cm (A)mean current demand (7.4.2)I cf (A)final current demand (7.4.2)i c (A/m²)design current density (6.3.1)i ci (A/m²)design initial current density (6.3.1)i cm (A/m²)design mean current density (6.3.5)i cf (A/m²)design final current density (6.3.1)L (m)anode length (Table 10-7)M a (kg)total net anode mass (7.7.1)m a (kg)(individual) net anode mass (7.8.3)m ai (kg)(individual) initial net anode mass (7.9.3)m af (kg)(individual) final net anode mass (7.9.3)N number of anodes (7.8.1)r (m)anode radius (Table 10-7)R a (ohm)(individual) anode resistance (6.6.1)R ai (ohm)(individual) anode initial resistance (7.9.2)R af (ohm)(individual) anode final resistance (7.9.2)R a tot (ohm)total anode resistance (6.3.4)S (m)arithmetic mean of anode length and width (Table 10-7)ρ (ohm·m)seawater/sediment resistivity (6.7.1)t f (years)design life (6.4.4)uanode utilisation factor (6.8)Δw (g)weight loss associated with quality control testing of anode materials (11.3.10)see note on front cover 5. General CP Design Considerations (Informative) – Page 115.3.2 The above parameters are interrelated and vary with geographical location, depth and season. It is not feasible to give an exact relation between the seawater environmental parameters indicated above and cathodic current demands to achieve and to maintain CP. To rationalise CP design for marine applications, default design current densities, i c (A/m2), are defined in this document based on 1) climatic regions (related to mean seawater surface temperature) and 2) depth. The ambient seawater temperature and salinity determine the specific seawater resistivity, ρ (ohm·m), which is used to calculate the anode resistance, R a (ohm), a controlling factor for the current output from an anode.5.4 Protective Potentials5.4.1 A potential of - 0.80 V relative to the Ag/AgCl/seawater reference electrode is generally accepted as the design protective potential E c° (V) for carbon and low-alloy steels. It has been argued that a design protective potential of - 0.90 V should apply in anaerobic environments, including typical seawater sediments. However, in the design procedure advised in this RP, the protective potential is not a variable.5.4.2 For a correctly designed galvanic anode CP system, the protection potential will for the main part of the design life be in the range - 0.90 to - 1.05 (V). Towards the end of the service life, the potential increases rapidly towards - 0.80 (V), and eventually to even less negative values, referred to as ‘under-protection’. The term ‘over-protection’ is only applicable to protection potentials more negative than - 1.15 (V). Such potentials will not apply for CP by galvanic anodes based on Al or Zn.5.5 Detrimental effects of CP5.5.1 Cathodic protection will be accompanied by the formation of hydroxyl ions and hydrogen at the surface of the protected object. These products may cause disbonding of non-metallic coatings by mechanisms including chemical dissolution and electrochemical reduction processes at the metal/coating interface, possibly including build-up of hydrogen pressure at this interface. This process of coating deterioration is referred to as ‘cathodic disbonding’. On components containing hot fluids, the process is accelerated by heat flow to the metal/coating interface.5.5.2 Coatings applied to machined or as-delivered surfaces of corrosion resistant alloys (CRAs) are particularly prone to cathodic disbonding. However, with surface preparation to achieve an optimum surface roughness, some coating systems (e.g. those based on epoxy or polyurethane) have shown good resistance to cathodic disbonding by galvanic anode CP, when applied to CRAs as well as to carbon and low-alloy steel. For coating systems whose compatibility with galvanic anode CP is not well documented, Owner should consider carrying out qualification testing, including laboratory testing of resistance to cathodic disbondment. Testing of marine coatings’ resistance to cathodic disbondment has been standardised, e.g. in ASTM G8.5.5.3 Cathodic protection will cause formation of atomic hydrogen at the metal surface. Within the potential range for CP by aluminium or zinc based anodes (i.e. - 0.80 to - 1.10 V Ag/AgCl/seawater), the production of hydrogen increases exponentially towards the negative potential limit. The hydrogen atoms can either combine forming hydrogen molecules or become absorbed in the metal matrix. In the latter case, they may interact with the microstructure of components subject to high stresses causing initiation and growth of hydrogen-related cracks, here referred to as ‘hydrogen induced stress cracking’ (HISC).5.5.4 For all practical applications, austenitic stainless steels and nickel based alloys are generally considered immune to HISC in the solution annealed condition. With the exceptions of UNS S30200 (AISI 302) and UNS S30400 (AISI 304) stainless steel, moderate cold work does not induce HISC sensitivity of these materials. The same applies for welding or hot forming according to an appropriate procedure. Bolts in AISI 316 stainless steel manufactured according to ISO 3506, part 1, grade A4, property class 80 and lower (up to SMYS 640 MPa) have proven compatibility with galvanic anode CP.5.5.5 For certain nickel based alloys (i.e. austenitic alloys including e.g. UNS N05500 and N07750), precipitation hardening may induce high sensitivity to HISC. For precipitation hardened austenitic stainless steels, the susceptibility is lower and a hardness of max. 300 HV may be considered a reasonably safe limit, whilst materials with hardness higher than 350 HV should generally be avoided for any components to receive CP. In the intermediate hardness range (i.e. 300 to 350 HV), precautions should be applied during design to avoid local yielding and/or to specify a qualified coating system as a barrier to hydrogen absorption by CP. The qualification of coatings for this purpose should include documentation of resistance to disbonding in service by environmental effects, including CP and any internal heating.5.5.6 Based on practical experience, ferritic and ferritic-pearlitic structural steels with specified minimum yield strength (SMYS) up to at least 500 MPa have proven compatibility with marine CP systems. (However, laboratory testing has demonstrated susceptibility to HISC during extreme conditions of yielding). It is recommended that all welding is carried out according to a qualified procedure with 350 HV as an absolute upper limit. With a qualified maximum hardness in the range 300 to 350 HV, design measures should be implemented to avoid local yielding and to apply a reliable coating system as a barrier to CP induced hydrogen absorption.。
基于DNV-RP-F101规范的腐蚀海底管道强度评估研究
基于DNV-RP-F101规范的腐蚀海底管道强度评估研究王猛;赵冬岩【摘要】近年来海底管道由于腐蚀缺陷造成失效的事件有增多的趋势。
为了评估在管道发生腐蚀后失效的风险性,对DNV-RP-F101的腐蚀管道强度评估方法进行研究,通过算例对影响强度评估的关键因素进行了敏感性分析,并对DNV-RP-F101和DNV-OS-F101的关系进行了探讨。
结果表明,影响强度评估结果的三个主要因素中,缺陷检测数据误差对评估结果影响最大。
当满足一定条件时,屈强比对评估结果的影响可忽略。
【期刊名称】《海洋工程装备与技术》【年(卷),期】2017(004)005【总页数】5页(P276-280)【关键词】海底管道腐蚀缺陷强度评估【作者】王猛;赵冬岩【作者单位】海洋石油工程股份有限公司,天津300451;海洋石油工程股份有限公司,天津300451【正文语种】中文【中图分类】TE973随着国内海洋工程的发展，我国在役海底管道总长度已超过6000km。
但由于运营维护技术和管理上的原因，多数管道自从投产以来未进行任何清管、通球等基本的维护活动。
20%的海底管道无法进行内检，管道的腐蚀和强度现状对管道安全运行存在重大影响。
腐蚀导致管道壁厚减薄,使管道承压能力降低且引起应力集中。
当腐蚀缺陷的深度和数量达到一定程度时，为维护管道而进行的修复、停工将造成经济损失。
更为严重的是管道发生破裂，引发事故。
因此，国内对缺陷检测和评估的需求日益迫切。
对管道缺陷的检测和评估技术已经发展了40年，并形成了成熟的规范。
美国Battlle研究所根据断裂力学理论和爆裂试验结果提出了半理论半经验公式NG-18[1]；美国机械工程师协会(ASME)在此基础上建立了腐蚀管道评估规范ASMEB31G[2]；Kiefner等[3]在NG-18的基础上对其进行了修正，将短腐蚀近似为抛物线形腐蚀，而将长腐蚀近似为矩形腐蚀，称之为改进的B31G方法；Fu等[4]釆用非线性有限元模拟分析腐蚀管道承压状态，证明基于应力失效准则的非线性有限元分析方法能较为准确地预测腐蚀管道的极限内压；挪威船级社(DNV)对腐蚀海底管道进行一系列数值模拟和试验研究,并结合英国天然气公司的研究成果,形成了DNV-RP-F101腐蚀管道剩余强度评估推荐规范[5]。
DNV挪威船级社船规
船舶入级规范新造船舶材料与焊接第二篇第二章金属材料2001年1月目录第一节结构用轧制钢材第二节锅炉、压力容器以及特殊用途轧制钢材第三节复合钢板第四节钢管及附件第五节锻钢件第六节锚链用圆钢第七节铸钢件第八节铸铁件第九节铝合金第十节铜合金第十一节耐热有色合金目录第1节结构用轧制钢材A．通则A 100适用范围A 200钢材等级符号A 300制造方法B．普通强度钢B 100适用范围B 200化学成分B 300热处理、供应状态B 400机械性能C．高强度钢C 100适用范围C 200化学成分C 300热处理、供应状态C 400机械性能D．超高强度钢D 100适用范围D 200化学成分D 300热处理、供应状态D 400机械性能E．试验E 100试验材料E 200拉力试验E 300冲击试验E 400厚度方向性能试验E 500检验-容差F．修补F 100表面缺陷第2节锅炉、压力容器以及特殊用途轧制钢材A．通则A 100适用范围A 200制造方法B．锅炉和受压容器用钢B 100钢材等级B 200化学成分B 300机械性能B 400热处理C．低温用钢C 100钢材等级C 200化学成分C 300机械性能C 400热处理D．不锈钢D 100钢材等级D 200化学成分D 300机械性能D 400热处理D 500晶间腐蚀倾向试验E．试验E 100一般要求E 200常温下的拉力试验E 300高温下的拉力试验E 400冲击试验E 500落锤试验E 600厚度方向性能试验E 700晶间腐蚀倾向试验F．检验、尺寸容差和表面状态F 100检验F 200容差F 300表面状态和缺陷修整第3节复合钢板A．通则A 100适用范围A 200热处理B．基体材料B 100一般规定C．包覆金属C 100一般规定C 200化学成分D．试验D 100一般规定D 200拉力试验D 300冲击试验D 400弯曲试验D 500剪切试验D 600超声波试验D 700腐蚀试验D 800检验-容差E．修补和拒收E 100表面缺陷E 200拒收F．材料的标记F 100标记第4节钢管A．通则A 100适用范围A 200制造A 300质量A 400尺寸的容差A 500化学成分A 600热处理A 700机械性能A 800试验材料A 900外观检查和无损探伤A 1000液压试验A 1100重复试验A 1200标记A 1300证书B．常压管系用钢管B 100适用范围B 200制造B 300化学成分B 400热处理B500机械性能C．不锈钢压力管C 100适用范围C200制造C 300化学成分C 400热处理C 500机械性能C 600腐蚀试验D．低温用钢管D 100适用范围D200制造D 300化学成分D 400热处理D 500机械性能E．锅炉、热交换器和过热器用钢管E 100适用范围E 200制造E 300化学成分E 400热处理E 500机械性能F．附件F 100适用范围F 200材料F 300制造F 400热处理F 500机械性能F 600 硬度试验F 700 腐蚀试验F 800 表面光洁度和尺寸F 900印记和证书第5节锻钢件A．通则A 100适用范围A 200制造A 300质量A 400化学成分A 500热处理A 600 试块A 700常温下的机械试验A 800高温下的拉力试验A 900重复试验A 1000外观检查和无损探伤A 1100 缺陷锻件的修整A 1200证书B、一般用途锻钢件B 100适用范围B 200钢材类型B 300化学成分B 400热处理B500试块和机械性能C、轴系和机械锻钢件C 100适用范围C 200钢材类型C 300化学成分C 400热处理C 500试块C 600机械性能D、齿轮锻钢件D 100适用范围D 200制造D 300化学成分D 400热处理D 500正火加回火和淬火加回火锻件的试验材料D 600用于渗碳和硬化处理锻件的试验材料D 700机械性能E、锅炉、非点火的压力容器和机械管系锻钢件E 100适用范围E 200化学成分E 300热处理E 400 试验材料E 500机械性能F、裸露于低温的液货舱、压力容器和管系用锻钢件F 100适用范围F 200钢材类型F 300化学成分F 400热处理F 500试验材料F 600机械性能第6节锚链用圆钢A 100适用范围A 200钢的等级A 300化学成分A 400机械性能A 500 热处理B、试验B 100试验数量B 200冲击试验C、材料标记C 100印记第7节铸钢件A 100适用范围A 200铸造A 300铸件质量A 400化学成分B 100钢的类型B 200化学成分B 300机械性能C、锅炉、非点火的压力容器和机械管系铸钢件C 100钢的类型C 200化学成分C 300机械性能D、螺旋桨铸钢件D 100钢的类型D 200机械性能E、锚链环、附件、锚卸扣用的铸钢件E 100锚链环E 200锚链附件和锚卸扣F、有高韧性要求的结构构件用的铸钢件F 100钢的类型F 200化学成分F 300机械性能G、液化气系统用的铸钢件G 100钢的类型G 200化学成分G 300机械性能H、热处理H 100一般要求H 200碳钢和碳锰钢的热处理H 300低合金钢的热处理H 400不锈钢的热处理I、试验I 100试样I 200高温下的机械试验I 300高温下的拉力试验I 400液压试验I 500外观检查和无损探伤J、有缺陷铸件的修整J 100补焊K、结构构件的焊接K 100一般要求第8节铸铁件A 100适用范围A 200 铸件质量A 300制造A 400化学成分A 500热处理A 600试验A 700外观检查和无损探伤A 800缺陷修补B、球墨铸铁B 100 适用范围B 200试验材料B 300机械性能B 400金相检验C、灰铸铁C 100 适用范围C 200试验材料C 300机械性能第9节熟铝合金A、通则A 100适用范围A 200铝材等级A 300化学成分A 400回火符号A 500机械性能B、试验B 100试样B 200拉力试验B 300其他试验B 400检验、容差C、缺陷修补C 100一般要求D、材料标记D 100标记第10节铜合金A、通则A 100适用范围B、阀件、附件和一般用途的铸件B 100铜合金类型B 200化学成分B 300机械性能B 400试验C、螺旋桨铸件C 100化学成分C 200机械性能C 300热处理C 400试验和检验C 500缺陷修补D、管材D 100化学成分D 200机械性能D 300热处理D 400试验第11节耐热有色合金A、通则A 100适用范围A 200认可A 300热处理B、试验B 100试样B 200拉力试验B 300冲击试验B 400蠕变和断裂试验B 500无损探伤试验B 600其他试验第一节结构用轧制钢材A．通则A 100 适用范围101 本节规定了可焊普通强度、高强度和超高强度结构用热轧钢板和型材的要求，这些要求也适用于结构用无缝钢管。
挪威船级社DNV认证标准译件(全)
认证标准No.2.9类型鉴定程序 NO.1-501.8玻璃纤维增强材料1999年1月挪威船级社挪威荷维可N-1322 Veritasveien 电话：+47 67 57 9900 传真：+47 67 57 99 11目录1. 服务范围-------------------------------4 4.要求---------------------------------62. 步骤-------------------------------------4 4.1 类型鉴定的依据------------------62.1类型鉴定的申请----------------------4 4.2类型鉴定的范围------------------62.2报价-------------------------------------4 4.3一般要求---------------------------62.3类型鉴定文件评估-------------------4 4.4材料要求---------------------------62.4产品和生产设备的初次检查， 4.5类型试验用层压制品的要求---7包括现场观看类型试验-------------4 4.6装和产品标识要求---------------7 2.5检查报告和类型试验结果的评估--4 5. 附录 A: 玻璃纤维增强材料2.6类型鉴定证书的颁发-----------------4的类型鉴定 -------------------92.7两年后证书保留检查-----------------4 6.附录B：类型鉴定申请表2.8四年后证书更新的申请--------------5 90.01a---------------------------103. 须提交的文件--------------------------57. 附录C：类型鉴定证书3.1 定义--------------------------------------5 20.90a样本--------------------111.服务范围“挪威船级社类型鉴定”是基于ISO/IEC 指南2（1991）的定义：“根据对代表生产的一个产品的一个或多个样品进行系统的检查，鉴定其符合规定的要求”。
DNV RP-F101(挪威船级社 RP-F101油气管道腐蚀评价推荐标准 2004.10)
— Recommended Practices. Provide proven technology and sound engineering practice as well as guidance for the higher level Offshore Service Specifications and Offshore Standards.
DNV Offshore Codes consist of a three level hierarchy of documents:
— Offshore Service Specifications. Provide principles and procedures of DNV classification, certification, verification and consultancy services.
1.5 Structure of RP ........................................................5 5. 1.6 Applicable defects....................................................5
DNV-RP-B401 Cathodic Protection Design
DNV-RP-B401 Cathodic Protection Design1. General1.1 Introduction1.1.1 'Cathodic protection' (CP) can be defined as e.g. "electrochemical protection by decreasing the corrosion potential to a level at which the corrosion rate of the metal is significantly reduced" (ISO 8044) or "a technique to reduce corrosion of a metal surface by making that surface the cathode of an electrochemical cell" (NACE RP0176). The process of suppressing the corrosion potential to a more negative potential is referred to as 'cathodic polarization'.1.1.2 For galvanic anode CP systems, the anode of the electrochemical cell is a casting of an electrochemically active alloy (normally aluminium, zinc or magnesium based). This anode is also the current source for the CP system and will be consumed. Accordingly, it is often referred to as a 'sacrificial anode', as alternative to the term 'galvanic anode' consistently used in this Recommended Practice (RP). For 'impressed current' CP, an inert (non-consuming) anode is used and the current is supplied by a rectifier. In this RP, the cathode of the electrochemical cell (i.e. the structure, sub-system or component to receive CP) is referred to as the 'protection object'.1.1.3 For permanently installed offshore structures, galvanic anodes are usually preferred. The design is simple, the system is mechanically robust and no external current source is needed. In addition, inspection and maintenance during operation can largely be limited to periodic visual inspection of anode consumption and absence of visual corrosive degradation. However, due to weight and drag forces caused by galvanic anodes, impressed current CP systems are sometimes chosen for permanently installed floating structures.1.1.4 Cathodic protection is applicable for all types of metals and alloys commonly used for subsea applications. It prevents localised forms of corrosion as well as uniform corrosion attack, and eliminates the possibility for galvanic corrosion when metallic materials with different electrochemical characteristics are combined. However, CP may have certain detrimental effects, for example hydrogen related cracking of certain high-strength alloys and coating disbondment as described in 5.5.1.1.5 Cathodic protection is primarily intended for metal surfaces permanently exposed to seawater or marine sediments. Still, CP is often fully effective in preventing any severe corrosion in a tidal zone andhas a corrosion reducing effect on surfaces intermittently wetted by seawater.1.2 Scope1.2.1 This Recommended Practice (RP) has been prepared to facilitate the execution of conceptual and detailed CP design using aluminium or zinc based galvanic anodes, and specification of manufacture and installation of such anodes. Whilst the requirements and recommendations are general, this document contains advice on how amendments can be made to include project specific requirements. The RP can also easily be amended to include requirements or guidelines by a regulating authority, or to reflect owner's general philosophy on corrosion control by CP.1.2.2 Some of the design recommendations and methods in Sections 5, 6 and 7 are also valid for CP systems using other current sources such as magnesium anodes and rectifiers (i.e. impressed current).1.2.3 This RP is primarily intended for CP of permanently installed offshore structures associated with the production of oil and gas. Mobile installations for oil and gas production like semi-submersibles, jack-ups and mono-hull vessels are not included in the scope of this document. However, to the discretion of the user, relevant parts of this RP may be used for galvanic anode CP of such structures as well.1.2.4 Detailed design of anode fastening devices for structural integrity is not included in the scope of this RP. Considerations related to safety and environmental hazards associated with galvanic anode manufacture and installation are also beyond its scope.1.2.5 Compared to the 1993 edition of DNV-RP-B401, design considerations for impressed current CP have been deleted from the scope of the 2004 revision whilst the sections on anode manufacture and installation are made more comprehensive. CP of submarine pipelines is further excluded from the scope (see 1.5). However, this RP is applicable for CP of components of a pipeline system installed on template manifolds, riser bases and other subsea structures when such components are electrically connected to major surfaces of structural C-steel.In this revision, guidance and explanatory notes are contained in a 'Guidance note' to the applicable paragraph in Sections 6, 7, 8 and in Annex B and C. (Most of the Guidance notes are based on queries on the 1993 revision of DNV-RP-B401 and other experience from its use. Furthermore, some informative text in the old revision has been contained in such notes).All tables and figures associated with Sec.6 are contained in Annex A. The document has further been revised to facilitate specification of Purchaser information to Contractor, and optional requirements associated with CP design, manufacture and installation of anodes (see 1.3). Additional comments on revisions in this 2004 issue are made in the Introduction (last paragraph) of Sections 6, 7, 8 and Annex B and C.1.3 Objectives and Use1.3.1 This RP has two major objectives. It may be used as a guideline to Owner's or their contractors' execution of conceptual or detailed CP design, and to the specification of galvanic anode manufacture and installation. It may also be used as an attachment to an inquiry or purchase order specification for such work. If Purchaser has chosen to refer to this RP in a purchase document, then Contractor shall consider all requirements in Sections 6-9 of this document as mandatory, unless superseded by amendments and deviations in the specific contract. Referring to this document in a purchase document, reference shall also be made to the activities for which DNV-RP-B401 shall apply, i.e. CP design in Sections 6 and 7, anode manufacture in Sec.8 and/or anode installation in Sec.9.1.3.2 CP design, anode manufacture and anode installation are typically carried out by three different parties (all referred to as 'Contractor'). Different parties issuing a contract (i.e. 'Purchaser') may also apply. The latter includes 'Owner', e.g. for CP design and qualification of galvanic anode materials. For definition of contracting parties and associated terminology, see Sec.3.1.3.3 Specification of project specific information and optional requirements for CP detailed design, anode manufacture and anode installation are described in 7.1.2, 8.1.2 and 9.1.3, respectively.1.4 Document Structure1.4.1 Guidelines and requirements associated with conceptual and detailed CP design are contained in Sections 5, 6 and 7, whilst galvanic anode manufacture and installation are covered in Sec.8 and Sec.9, respectively. Tabulated data for CP design are compiled in Annex A. Annex B and C contain recommended procedures for laboratory testing of anode materials for production quality control and for documentation of long-term electrochemical performance, respectively.1.5 Relation to Other DNV Documents1.5.1 Cathodic protection of submarine pipelines is covered inDNV-RP-F103.2. References2.1 GeneralThe following standards (2.2-2.7) are referred to in this RP. The latest editions apply.2.2 ASTM (American Society for Testing andMaterials)ASTM G8 Test Method for Cathodic Disbonding of Pipeline Coating ASTM D1141 Specification for Substitute OceanSeawater2.3 DNV (Det Norske Veritas)DNV-RP-F103 Cathodic Protection of SubmarinePipelines by Galvanic Anodes2.4 EN (European Standards)EN 10204 Metallic Products - Types of Inspection Documents2.5 NORSOKNORSOK M-501 Standard for Surface Preparation and Protective Coating2.6 ISO (International Organization forStandardisation)ISO 3506 Mechanical Properties ofCorrosion-Resistant Stainless SteelFastenersISO 8044 Corrosion of Metals and Alloys; Basic Terms and DefinitionsISO 8501-1 Preparation of Steel Substrates forApplication of Paint and RelatedProducts - Visual Assessment of Surface Cleanliness.Part 1: Rust Grades and Preparation Grades of Uncoated SteelSubstrates.ISO 10005 Quality Management- Guidelines for Quality PlansISO 10474 Steel and Steel Products Inspection Documents2.7 NACE InternationalNACERP0176 Corrosion Control of Steel Fixed Offshore Structures Associated with Petroleum ProductionNACERP0387 Metallurgical and Inspection Requirements for Cast Sacrificial Anodes for Offshore Applications3. Terminology and Definitions3.1 TerminologyOwner Party legally responsible for design, construction and operation of the object to receive CP.Purchaser Party (Owner or main contractor) issuing inquiry or contract for CP design, anode manufacture or anode installation work, or nominated representative. Contractor Party to whom the work (i.e. CP design, anode manufacture or anode installation) has been contracted.shall indicates a mandatory requirement.should indicates a preferred course of action.may indicates a permissible course of action.agreed/agreement refers to a written arrangement between Purchaser and Contractor(e.g. as stated in a contract).report and notify refers to an action by Contractor in writing.acceptedacceptancerefers to a confirmation by Purchaser in writing.certificate certified refers to the confirmation of specified properties issued by Contractor or supplier of metallic materials according to EN 10204:3.1.B, ISO 10474:5.1-B or equivalent.purchasedocument(s)refers to an inquiry/tender or purchase/contract specification, as relevant.3.2 DefinitionsFor the following technical items below, definitions in the text apply:cathodic protection (1.1.1), galvanic anode (1.1.2), protection object (1.1.2), polarization (1.1.1), calcareous scale/layer (5.5.13), cathodic disbondment (5.5.1).References within parentheses refer to the applicable paragraph.For items applicable to quality control and CP design parameters, reference to the applicable paragraph is made in the list of abbreviations (4.1) and symbols (4.2).4. Abbreviations and Symbols4.1 AbbreviationsCP cathodic protectionCR concession request (8.5.6)CRA corrosion resistant alloyCTOD crack tip opening displacementDC direct currentDFT dry film thicknessHAZ heat affected zoneHISC hydrogen induced stress cracking (5.5.3)HV Vicker's hardnessITP inspection and testing plan (8.4.2)IPS installation procedure specification (9.2)MIP manufacture and inspection plan (8.4.2)MPS manufacture procedure specification (8.2)NDT non-destructive testingPQT production qualification test (8.3)PWHT post weld heat treatment (5.5.7)ROV remotely operated vehicleRP recommended practiceSCE standard calomel electrode (6.1.5)SMYS specified minimum yield strengthUNS unified numbering systemWPS welding procedure specificationWPQT welding procedure qualification testYS yield strength4.2 SymbolsA (m) anode surface area (Table 10-7)A(m) cathode surface area (7.4.1)ca constant in coating breakdown factor (6.4.2)b constant in coating breakdown factor (6.4.2)C (Ah) current charge associated with quality control testing ofanode materials (11.3.10)c (m) anode cross sectional periphery (Table 10-7)(Ah) (individual) anode current capacity (7.8.2)CaC(Ah) total anode current capacity (7.8.2)a tot° (V) design closed circuit anode potential (6.5.1)Ea° (V) design protective potential (7.8.2)Ec(V) global protection potential (6.3.4)E'cE'(V) (actual) anode closed circuit potential (6.3.4)a∆E° (V) design driving voltage (7.8.2)ε (Ah/kg) a node electrochemical capacity (6.5.1)fcoating breakdown factor (6.4.1)cinitial coating breakdown factor (6.4.4)fcifmean coating breakdown factor (6.4.4)cmffinal coating breakdown factor (6.4.4)cfI(A) (individual) anode current output (7.8.2)a(A) (individual) initial anode current output (7.8.2)Iai(A) (individual) final anode current output (7.8.2)Iaf(A) total anode current output (6.3.4)Ia totI(A) total initial current output (7.8.4)a tot i(A) total final current output (7.8.4)Ia tot fI(A) current demand (7.4.2)c(A) initial current demand (7.4.2, 6.3.1)IciI(A) mean current demand (7.4.2)cm(A) final current demand (7.4.2)Icfi(A/m) design current density (6.3.1)c(A/m) design initial current density (6.3.1)icii(A/m) design mean current density (6.3.5)cm(A/m) design final current density (6.3.1)icfL (m) anode length (Table 10-7)M(kg) total net anode mass (7.7.1)a(kg) (individual) net anode mass (7.8.3)ma(kg) (individual) initial net anode mass (7.9.3)maim(kg) (individual) final net anode mass (7.9.3)afN number of anodes (7.8.1)r (m) anode radius (Table 10-7)(ohm) (individual) anode resistance (6.6.1)RaR(ohm) (individual) anode initial resistance (7.9.2)ai(ohm) (individual) anode final resistance (7.9.2)RafR(ohm) total anode resistance (6.3.4)a totS (m) arithmetic mean of anode length and width(Table 10-7)seawater/sediment resistivity (6.7.1)ρ(ohm·m)(years) design life (6.4.4)tfu anode utilisation factor (6.8)∆w (g) weight loss associated with quality control testing of anode materials (11.3.10)5. General CP Design Considerations (Informative)5.1 General5.1.1 This section addresses aspects of cathodic protection which are primarily relevant to CP conceptual design, including the compatibility of CP with metallic materials and coatings. The content of this section is informative in nature and intended as guidelines for Owners and their contractors preparing for conceptual or detailed CP design. Nothing in this section shall be considered as mandatory if this RP has been referred to in a purchase document.5.1.2 Compared to the 1993 revision of this RP, the major revisions of this 2004 revision are contained in 5.5.5.2 Limitations of CP5.2.1 For carbon and low-alloy steels, cathodic protection should be considered as a technique for corrosion control, rather than to provide immunity (1.1.1). It follows that cathodic protection is not an alternative to corrosion resistant alloys for components with very high dimensional tolerances, e.g. sealing assemblies associated with subsea production systems.5.3 Environmental Parameters Affecting CP5.3.1 The major seawater parameters affecting CP in-situ are:—dissolved oxygen content—sea currents—temperature—marine growth—salinityIn addition, variations in seawater pH and carbonate content are considered factors which affect the formation of calcareous layers associated with CP and thus the current needed to achieve and to maintain CP of bare metal surfaces. In seabed sediments, the major parameters are: temperature, bacterial growth, salinity and sediment coarseness.5.3.2 The above parameters are interrelated and vary with geographical location, depth and season. It is not feasible to give an exact relation between the seawater environmental parameters indicated above and cathodic current demands to achieve and to maintain CP. To rationalise CP design for marine applications, default design current densities, ic (A/m2), are defined in this document based on 1) climatic regions (related to mean seawater surface temperature) and 2) depth. The ambient seawater temperature and salinity determine the specific seawater resistivity,(ohm), a (ohm·m), which is used to calculate the anode resistance, Ra controlling factor for the current output from an anode.5.4 Protective Potentials5.4.1 A potential of - 0.80 V relative to the Ag/AgCl/seawater reference° electrode is generally accepted as the design protective potential Ec (V) for carbon and low-alloy steels. It has been argued that a design protective potential of - 0.90 V should apply in anaerobic environments, including typical seawater sediments. However, in the design procedure advised in this RP, the protective potential is not a variable.5.4.2 For a correctly designed galvanic anode CP system, the protection potential will for the main part of the design life be in the range - 0.90 to - 1.05 (V). Towards the end of the service life, the potential increases rapidly towards - 0.80 (V), and eventually to even less negative values, referred to as 'under-protection'. The term 'over-protection' is only applicable to protection potentials more negative than - 1.15 (V). Such potentials will not apply for CP by galvanic anodes based on Al or Zn.5.5 Detrimental effects of CP5.5.1 Cathodic protection will be accompanied by the formation of hydroxyl ions and hydrogen at the surface of the protected object. Theseproducts may cause disbonding of non-metallic coatings by mechanisms including chemical dissolution and electrochemical reduction processes at the metal/coating interface, possibly including build-up of hydrogen pressure at this interface. This process of coating deterioration is referred to as 'cathodic disbonding'. On components containing hot fluids, the process is accelerated by heat flow to the metal/coating interface.5.5.2 Coatings applied to machined or as-delivered surfaces of corrosion resistant alloys (CRAs) are particularly prone to cathodic disbonding. However, with surface preparation to achieve an optimum surface roughness, some coating systems (e.g. those based on epoxy or polyurethane) have shown good resistance to cathodic disbonding by galvanic anode CP, when applied to CRAs as well as to carbon and low-alloy steel. For coating systems whose compatibility with galvanic anode CP is not well documented, Owner should consider carrying out qualification testing, including laboratory testing of resistance to cathodic disbondment. Testing of marine coatings' resistance to cathodic disbondment has been standardised, e.g. in ASTM G8.5.5.3 Cathodic protection will cause formation of atomic hydrogen at the metal surface. Within the potential range for CP by aluminium or zinc based anodes (i.e. - 0.80 to - 1.10 V Ag/AgCl/seawater), the production of hydrogen increases exponentially towards the negative potential limit. The hydrogen atoms can either combine forming hydrogen molecules or become absorbed in the metal matrix. In the latter case, they may interact with the microstructure of components subject to high stresses causing initiation and growth of hydrogen-related cracks, here referred to as 'hydrogen induced stress cracking' (HISC).5.5.4 For all practical applications, austenitic stainless steels and nickel based alloys are generally considered immune to HISC in the solution annealed condition. With the exceptions of UNS S30200 (AISI 302) and UNS S30400 (AISI 304) stainless steel, moderate cold work does not induce HISC sensitivity of these materials. The same applies for welding or hot forming according to an appropriate procedure. Bolts in AISI 316 stainless steel manufactured according to ISO 3506, part 1, grade A4, property class 80 and lower (up to SMYS 640 MPa) have proven compatibility with galvanic anode CP.5.5.5 For certain nickel based alloys (i.e. austenitic alloys includinge.g. UNS N05500 and N07750), precipitation hardening may induce high sensitivity to HISC. For precipitation hardened austenitic stainless steels, the susceptibility is lower and a hardness of max. 300 HV may be considered a reasonably safe limit, whilst materials with hardness higher than 350 HV should generally be avoided for any components to receive CP.In the intermediate hardness range (i.e. 300 to 350 HV), precautions should be applied during design to avoid local yielding and/or to specify a qualified coating system as a barrier to hydrogen absorption by CP. The qualification of coatings for this purpose should include documentation of resistance to disbonding in service by environmental effects, including CP and any internal heating.5.5.6 Based on practical experience, ferritic and ferritic-pearlitic structural steels with specified minimum yield strength (SMYS) up to at least 500 MPa have proven compatibility with marine CP systems. (However, laboratory testing has demonstrated susceptibility to HISC during extreme conditions of yielding). It is recommended that all welding is carried out according to a qualified procedure with 350 HV as an absolute upper limit. With a qualified maximum hardness in the range 300 to 350 HV, design measures should be implemented to avoid local yielding and to apply a reliable coating system as a barrier to CP induced hydrogen absorption.5.5.7 For martensitic carbon, low-alloy and stainless steels, failures by CP induced HISC have been encountered involving materials with an actual YS and hardness of about 700 MPa and 350 HV, respectively. It is widely recognised that untempered martensite is especially prone to HISC. Welding of materials susceptible to martensite formation should be followed by post weld heat treatment (PWHT) to reduce heat-affected zone (HAZ) hardness and residual stresses from welding. The same recommendations for hardness limits and design measures as for ferritic steels (5.5.6) apply. Bolts in martensitic steel heat treated to SMYS up to 720 MPa (e.g. ASTM A193 grade B7 and ASTM A320 grade L7) have well documented compatibility with CP. However, failures due to inadequate heat treatment have occurred and for critical applications, batch wise testing is recommended to verify a maximum hardness of 350 HV.5.5.8 Ferritic-austenitic ('duplex') stainless steels should be regarded as potentially susceptible to HISC, independent of SMYS (typically 400 to 550 MPa) or specified maximum hardness. Welding may cause increased HISC susceptibility in the weld metal and in the HAZ adjacent to the fusion line. This is related to an increased ferrite content rather than hardness. Qualification of welding should therefore prove that the maximum ferrite content in the weld metal and the inner HAZ (about 0.1 mm wide) can be efficiently controlled; contents of maximum 60 to 70% are typically specified. Forgings are more prone to HISC than wrought materials due to the course microstructure allowing HISC to propagate preferentially in the ferrite phase. Cold bent pipes of small diameter (uncoated and with mechanical connections, i.e. no welding) have proven records for CP compatibility when used as production control piping for subsea installations. Design precautions should include 1) measures to avoidlocal plastic yielding and 2) use of coating systems qualified for e.g. resistance to disbondment by mechanical and physical/chemical effects.5.5.9 Copper and aluminium based alloys are generally considered immune to HISC, regardless of fabrication modes. For high-strength titanium alloys, documentation is limited and special considerations (including e.g. qualification testing, see 5.5.10) should apply.5.5.10 There is no generally accepted test method to verify CP compatibility of different metallic materials. Constant extension rate testing (also referred to as "slow strain rate testing") is applicable to compare HISC susceptibility of materials of the same type (e.g. relative susceptibility of martensitic steels), but a comparison of different types of materials is less straightforward. For more quantitative testing, uni-axially loaded tensile specimens (with constant load), 4-point bend specimens (with constant displacement), crack tip opening displacement (CTOD) and other testing configurations have been applied at controlled CP conditions. Such testing is, however, beyond the scope of this document.5.5.11 Special techniques have been applied to control the CP protective potential to a less negative range (e.g. - 0.80 to - 0.90 V), including the use of diodes and special anode alloys, but practical experience is limited. A major disadvantage of this approach is that the individual component or system needs to be electrically insulated from adjacent "normal" CP systems.5.5.12 Cathodic protection in closed compartments without ventilation may cause development of hydrogen gas to an extent that an explosive gas mixture (i.e. hydrogen/oxygen) may eventually develop. The risk is moderate with Al and Zn-base galvanic anodes but at least one explosion during external welding on a water flooded platform leg containing such anodes has been related to this phenomenon. (Closed water flooded compartments will not normally require CP, see6.3.7).5.5.13 A consequence of CP application is that a calcareous layer (consisting primarily of calcium carbonate) will form on bare metal surfaces. The thickness is typically of the order of a tenth of a millimetre, but thicker deposits may occur. The calcareous layer reduces the current demand for maintenance of CP and is therefore beneficial. A calcareous layer may, however, obstruct mating of subsea electrical and hydraulic couplers with small tolerances. This may be prevented by applying an insulating layer of a thin film coating (e.g. baked epoxy resin). An alternative measure is to electrically insulate the connectors from the CP system and use seawater resistant materials for all wettedparts. High-alloyed stainless steels, nickel-chromium-molybdenum alloys, titanium and certain copper based alloys (e.g. nickel-aluminium bronze) have been used for this purpose.5.5.14 Galvanic anodes may interfere with subsea operations and increase drag forces by flowing seawater (see 5.7.3).5.5.15 CP eliminates the anti-fouling properties of copper based alloys in seawater.5.6 Galvanic Anode Materials5.6.1 Galvanic anodes for offshore applications are generally based on either aluminium or zinc. The generic type of anode material (i.e. aluminium or zinc base) is typically selected by Owner and specified in the conceptual CP design report and/or in the design premises for detailed CP design.5.6.2 Aluminium based anodes are normally preferred due to their higher electrochemical capacity, (A·h/kg). However, zinc based anodes have sometimes been considered more reliable (i.e. with respect to electrochemical performance) for applications in marine sediments or internal compartments with high bacterial activity, both environments representing anaerobic conditions.5.6.3 Some manufacturers offer proprietary anode alloys. Purchaser may require that the anode manufacturer shall document the electrochemical performance of their products by operational experience or by long term testing in natural seawater. (A recommended testing procedure is contained in Annex C).5.7 Anode Geometry and Fastening Devices5.7.1 There are three major types of anodes for offshore structures:—slender stand-off—elongated, flush mounted—braceletStand-off and flush-mounted anodes may further be divided into "short" and "long", based on the length to width ratio. The anode type determines the anode resistance formula (6.6) and anode utilisation factor (6.8) to be applied.。
DNV-OS-E302 2008
OFFSHORE STANDARDD ET N ORSKE VERITAS DNV-OS-E302OFFSHORE MOORING CHAINOCTOBER 2008This booklet has since the main revision (October 2008) been amended, most recently in October 2009.See the reference to “Amendments and Corrections” on the next page.Comments may be sent by e-mail to rules@ For subscription orders or information about subscription terms, please use distribution@ Comprehensive information about DNV services, research and publications can be found at http :// , or can be obtained from DNV, Veritasveien 1, NO-1322 Høvik, Norway; Tel +47 67 57 99 00, Fax +47 67 57 99 11.© Det Norske Veritas. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, without the prior written consent of Det Norske Veritas.Computer Typesetting (Adobe FrameMaker) by Det Norske Veritas.If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compen-sation shall never exceed USD 2 million.In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalf of Det Norske Veritas.FOREWORDDET NORSKE VERITAS (DNV) is an autonomous and independent foundation with the objectives of safeguarding life, prop-erty and the environment, at sea and onshore. DNV undertakes classification, certification, and other verification and consultancy services relating to quality of ships, offshore units and installations, and onshore industries worldwide, and carries out research in relation to these functions.DNV Offshore Codes consist of a three level hierarchy of documents:—Offshore Service Specifications. Provide principles and procedures of DNV classification, certification, verification and con-sultancy services.—Offshore Standards. Provide technical provisions and acceptance criteria for general use by the offshore industry as well as the technical basis for DNV offshore services.—Recommended Practices. Provide proven technology and sound engineering practice as well as guidance for the higher level Offshore Service Specifications and Offshore Standards.DNV Offshore Codes are offered within the following areas:A)Qualification, Quality and Safety MethodologyB)Materials TechnologyC)StructuresD)SystemsE)Special FacilitiesF)Pipelines and RisersG)Asset OperationH)Marine OperationsJ)Wind TurbinesO)Subsea SystemsAmendments and CorrectionsWhenever amendments and corrections to the document are necessary, the electronic file will be updated and a new Adobe PDF file will be generated and made available from the Webshop (/global/).Amended October 2009Offshore Standard DNV-OS-E302, October 2008 see note on front cover Changes – Page 3CHANGES•GeneralBeing class related, this document is published electronically only (as of October 2008) and a printed version is no longer available. The update scheme for this category of documents is different compared to the one relevant for other offshore doc-uments (for which printed versions are available).For an overview of all types of DNV offshore documents and their update status, see the “Amendments and Corrections”document located at: /global/, under category “Offshore Codes”.•Main changes as of October 2008:This standard replaces Certification Note 2.6 (August 1995) -“Certification of Offshore Mooring Chain”.The following is amended:—specification for stud less chain is no longer tentative—requirements to grade R4S and to R5 included—mechanical tests of test coupons taken from full scale accessories—scope of survey for chain and accessories—“approval of manufacturer” programme has been removed.See DNV Standard. for Certification No.2.9.•Main changes as of October 2009Since the previous edition (October 2008), this document has been amended, latest in October 2009. All changes have been incorporated. The changes are considered to be of editorial nature, thus no detailed description has been given.D ET N ORSKE V ERITASOffshore Standard DNV-OS-E302, October 2008Amended October 2009 Page 4 – Changes see note on front coverD ET N ORSKE V ERITASAmended October 2009Offshore Standard DNV-OS-E302, October 2008 see note on front cover Contents – Page 5CONTENTSCH. 1INTRODUCTION (7)Sec. 1Introduction (9)A.General (9)A100Introduction (9)A200Scope and application (9)B.Normative References (9)B100General (9)B200Reference documents (9)C.Definitions (9)C100Verbal forms (9)C200Terms (10)CH. 2TECHNICAL PROVISIONS (11)Sec. 1Materials (13)A.General Requirements (13)A100Scope (13)A200Manufacture (13)A300Chemical composition (13)A400Heat treatment (13)A500Mechanical testing (13)A600Inspection (14)A700Repair (14)A800Identification (14)A900 A 900 Records (14)B.Rolled Steel Bars (14)B100Scope (14)B200Manufacture (14)B300Chemical composition (14)B400Condition of supply and heat treatment (14)B500Mechanical testing (14)B600Hydrogen embrittlement testing (14)B700Dimensions and tolerances (15)B800Inspection (15)B900Repair (15)C.Steel Forgings (15)C100Scope (15)C200Manufacture (15)C300Chemical composition (15)C400Heat treatment (15)C500Mechanical testing (15)C600Inspection (15)C700Repair (15)D.Steel Castings (15)D100Scope (15)D200Manufacture (15)D300Chemical composition (15)D400Heat treatment (16)D500Mechanical testing (16)D600Inspection (16)D700Repair (16)E.Materials for Studs (16)E100Scope...............................................................................16E200Chemical composition. (16)Sec. 2Mooring Chain Cables and Accessories (18)A.General Requirements (18)A100Scope (18)A200Inspection (18)A300Repair (18)A400Identification (18)A500Records (18)B.Mooring Chain (18)B100Scope (18)B200Design (18)B300Manufacture (18)B400Welding of studs (18)B500Heat treatment (18)B600Proof load testing (19)B700Breaking load testing (19)B800Mechanical testing (19)B900Dimensions and tolerances (20)B1000Inspection (20)B1100Repair (21)B1200Identification (21)C.Chain Accessories (21)C100Scope (21)C200Design (21)C300Proof load testing (21)C400Breaking load testing (21)C500Mechanical testing (21)C600Dimensions and tolerances (22)C700Inspection (22)C800Repair (22)C900Identification (22)CH. 3CERTIFICATION AND CLASSIFICATION 25 Sec. 1Certification and Classification -Requirements (27)A.General (27)A100Introduction (27)A200Certification and classification principles (27)A300Assumptions (27)A400Documentation requirements (27)B.Certification and Classification Requirements (27)B100General (27)B200Information to be supplied by the purchaser (27)B300Design verification (27)B400Approval of manufacturers (27)B500Survey during manufacture (27)B600Certification of materials (27)B700Certification of mooring chain and accessories (28)App. A Scope of Survey for Mooring Chain (29)App. B Scope of Survey for Mooring Chain Accessories (30)D ET N ORSKE V ERITASOffshore Standard DNV-OS-E302, October 2008Amended October 2009 Page 6 – Contents see note on front coverD ET N ORSKE V ERITASD ET N ORSKE V ERITASVeritasveien 1, NO-1322 Høvik, Norway Tel.: +47 67 57 99 00 Fax: +47 67 57 99 11OFFSHORE STANDARDDNV-OS-E302OFFSHORE MOORING CHAINCHAPTER 1INTRODUCTIONCONTENTSPAGE Sec.1Introduction (9)Amended October 2009Offshore Standard DNV-OS-E302, October 2008 see note on front cover Ch.1 Sec.1 – Page 9SECTION 1INTRODUCTIONA. GeneralA 100Introduction101 This offshore standard contains criteria, technical requirements and guidance on materials, design, manufacture and testing of offshore mooring chain and accessories.102 The standard has been written for general world-wide application. Governmental regulations may include require-ments in excess of the provisions by this standard depending on the size, type, location and intended service of the offshore unit or installation.103 The objectives of this standard are to:—provide an internationally acceptable standard of safety by defining minimum requirements for offshore mooring chain and accessories—serve as a contractual reference document between manu-facturers and purchasers—serve as a guideline for designers, suppliers, purchasers and regulators—specify procedures and requirements for offshore mooring chain and accessories subject to DNV certification and classification.104 This standard is divided into three main chapters: —Chapter 1: Section 1 with general information, scope, def-initions and references—Chapter 2: Sections 1 and 2 with technical provisions for materials and chain cables—Chapter 3: Section 1, Appendix A and B giving specific procedures and requirements applicable for certification and classification of materials and chain cables in accord-ance with this standard. Also, requirements to design ver-ification are given.A 200Scope and application201 The mooring chain and accessories specified herein are intended for position mooring applications such as: mooring of mobile offshore units, mooring of floating production units, mooring of offshore loading systems, and mooring of gravity base structures during fabrication.202 Mooring chain links covered are common stud links and common stud less links, connecting common links (splice links), enlarged links and end links.203 Mooring chain accessories covered are detachable con-necting links (shackles), connecting plates (triplates etc), end (anchor) shackles, swivels and swivel shackles.B. Normative ReferencesB 100General101 The standards in Table B1 include provisions which, through reference in this text, constitute provisions of this off-shore standard. Latest issue of the standards shall be used unless otherwise agreed.102 Other recognised standards may be used provided it can be demonstrated that these meet or exceed the requirements of the standards in Table B1.103 Any deviations, exceptions and modifications to the design codes and standards shall be documented and agreed between the supplier, purchaser and verifier, as applicable. B 200Reference documents201 Applicable reference documents are given in Table B1.C. DefinitionsC 100Verbal forms101 Shall: Indicates requirements strictly to be followed in order to conform to this standard and from which no deviation is permitted.102 Should: Indicates that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required. Other possibilities may be applied subject to agreement.103 May: Verbal form used to indicate a course of action permissible within the limits of the standard.104 Agreement, agreed or by agreement: Unless otherwise indicated, agreed in writing between manufacturer and pur-chaser.Table B1 Normative referencesNo.TitleASTM E112Test Methods for Determining Average Grain Size ASTM E381Method of Macro-etch Testing Steel Bars, Billets,Blooms and ForgingsISO 4967Steel – Determination of content of non-metallicinclusions – Micrographic method using standarddiagramsASTM A255Standard Test Methods for Determining Harden-ability of SteelDNV-OS-B101Metallic materialsISO 9712 Non-destructive testing Qualification and certifi-cation of personnelEN 473 Non destructive testing - Qualification and certifi-cation of NDT personnel - General principles SNT-TC-1A(ASNT)Personnel Qualification and Certification in Non-destructive TestingEN 10228-1/3Non-destructive testing of steel forgingsASTM A275 Standard Practice for Magnetic Particle Examina-tion of Steel ForgingsASTM A388 Standard Practice for Ultrasonic Examination ofHeavy Steel ForgingsASTM E709 Standard Guide for Magnetic Particle Examina-tionASTM A609Standard Practice for Castings, Carbon, Low-Alloy and Martensitic Stainless Steel, UltrasonicExamination ThereofISO 1704Ships and marine technology – Stud-link anchorchainsAPI Spec 2F Specification for mooring chainASTM E587Practice for Ultrasonic Angle-Beam Examinationby the Contact MethodASME IX Welding and Brazing QualificationsEN 287 Approval testing of welders - Fusion weldingEN 288Specification and approval of welding proceduresfor metallic materialsISO 9606 Approval testing of welders - Fusion welding ASTM A488Practice for Steel Castings, Welding, Qualifica-tions of Procedures and PersonnelD ET N ORSKE V ERITASOffshore Standard DNV-OS-E302, October 2008Amended October 2009 Page 10 – Ch.1 Sec.1see note on front coverC 200Terms201 Purchaser: The owner or another party acting on his behalf, who is responsible for procuring materials, components or services intended for the design, fabrication or modification of a unit or installation.202 Manufacturer: The party who is contracted to be respon-sible for planning, execution and documentation of manufac-turing.D ET N ORSKE V ERITASD ET N ORSKE V ERITASVeritasveien 1, NO-1322 Høvik, Norway Tel.: +47 67 57 99 00 Fax: +47 67 57 99 11OFFSHORE STANDARDDNV-OS-E302OFFSHORE MOORING CHAINCHAPTER 2TECHNICAL PROVISIONSCONTENTSPAGE Sec.1Materials ..................................................................................................................................13Sec.2Mooring Chain Cables and Accessories.. (18)Amended October 2009Offshore Standard DNV-OS-E302, October 2008 see note on front cover Ch.2 Sec.1 – Page 13SECTION 1MATERIALSA. General RequirementsA 100Scope101 Sub-section A specifies the general requirements for rolled steel bars, steel forgings and steel castings to be used in the manufacture of offshore mooring chain and accessories. Specific requirements are given in B to D. If the specific requirements differ from these general requirements, the specific requirements shall prevail. Separate requirements for materials for studs are given in E.102 The steels concerned are classified by specified mini-mum ultimate tensile strength into five grades: R3, R3S, R4, R4S and R5.A 200Manufacture201 The steels shall be manufactured by an electric or one of the basic oxygen processes or any other approved process involving secondary refining. Steel grades R4S and R5 shall be vacuum degassed.202 The steels shall be killed and fine grain treated. The austenite grain size shall be 5 or finer in accordance with ASTM E112. The fine grain size requirement shall be deemed to be fulfilled if the steels contain Al, Nb, V or Ti, either singly or in any combination, as follows: When Al is used singly, the minimum total content shall be 0.020% or, alternatively, the Al to N ratio shall be minimum 2:1. When Al and Nb are used in combination, the minimum total Al content shall be 0.015% and the minimum Nb content shall be 0.010%. When Al and V are used in combination, the minimum total Al content shall be 0.015% and the minimum V content shall be 0.030%.203 For steel grades R4S and R5, the following information shall be supplied by the manufacturer to the mooring chain or accessory manufacturer and the results included in the chain documentation:a)Each heat shall be examined for non-metallic inclusionsaccording to ISO 4967 or equivalent. The level of inclu-sions shall be quantified and assessed to be sure inclusion levels are acceptable for the final product.b) A sample from each heat shall be macro etched accordingto ASTM E381 or equivalent to be sure there is no injuri-ous segregation or porosity.c)Jominy hardening ability data according to ASTM A255or equivalent shall be supplied with each heat.204 The manufacturer shall ensure that effective manufac-ture and process controls are implemented in production. Where deviation from the controls occurs and this could pro-duce products of inferior quality, the manufacturer shall inves-tigate to determine the cause and establish countermeasures to prevent its recurrence. Investigation reports to this effect shall be made available to the purchaser on request.A 300Chemical composition301 Specifications for chemical composition shall be agreed between the manufacturer and purchaser. Steel grades R4, R4S and R5 shall contain a minimum of 0.20% molybdenum. 302 The chemical composition of each heat shall be determined on a sample taken preferably during the pouring of the heat and shall comply with the specified limits. When multiple heats are tapped into a common ladle, the ladle analysis shall apply.303 The composition shall be determined after all alloying additions have been made and sufficient time allowed for such an addition to homogenize.304 Elements designated as residual and impurity elements in the individual specifications shall not be intentionally added to the steels. The content of such elements shall be reported. 305 Adequate controls shall be in place to prevent accumu-lation of harmful elements such as tin, antimony and arsenic in the final product.A 400Heat treatment401 Materials shall be heat treated for mechanical properties as specified in B to D. Heat treatment shall be carried out in a properly constructed furnace which is efficiently maintained and has adequate means for temperature control and is fitted with recording-type pyrometers. The furnace dimensions shall be such as to allow the whole furnace charge to be uniformly heated to the necessary temperature.402 Sufficient thermocouples shall be connected to the fur-nace charge where it is composed of forged or cast compo-nents. Thermocouples should be connected by capacitor discharge welding.403 Records shall identify the furnace used, furnace charge, date, temperature and time at temperature.404 The manufacturer shall ensure that the specified heat treatment is adhered to. Where deviation from the specified heat treatment occurs, the manufacturer shall ensure that affected products are tested or submitted to reheat treatment and that an investigation is carried out according to A204.A 500Mechanical testing501 Products shall be grouped in test units and sampled for mechanical testing as detailed in B to D. Test material from which test pieces are prepared shall be of equivalent cross sec-tion and be fully representative of the sample product and, where appropriate, shall not be cut, or partially cut from the sample product leaving a ligament, until heat treatment has been completed. Test material and test pieces shall not be sep-arately heat treated in any way.502 Test material and test pieces shall be marked to identify them with the products represented.503 For each test unit, one tensile and three Charpy V-notch test pieces shall be taken. Rolled steel bars and steel forgings shall be tested in the longitudinal direction. The longitudinal axis of test pieces shall be located one-third of the radius or, in the case of non-cylindrical sections, one-sixth of the diagonal from the outer surface.504 The preparation of test pieces and the procedures used for mechanical testing shall comply with the relevant require-ments of DNV-OS-B101.505 The materials shall comply with the mechanical proper-ties specified in Table E1.506 If the results from tensile testing do not meet the speci-fied requirements, two further tensile tests may be made from the same sample. If both of these additional tests are satisfac-tory, the test unit may be accepted.507 If the results from a set of three impact test pieces do not meet the specified requirements, three additional test pieces from the same sample may be tested and the results added to those previously obtained to form a new average. If this new average complies with the requirements and if not more than two individual results are lower than the required average and, of these, not more than one result is below 70% of the specified average value, the test unit may be accepted.508 Where forgings or castings and the associated test mate-rial are submitted to re-heat treatment, they may not be re-austenitised more than twice. All the tests previously per-D ET N ORSKE V ERITASOffshore Standard DNV-OS-E302, October 2008Amended October 2009 Page 14 – Ch.2 Sec.1see note on front coverformed shall be repeated after re-heat treatment and the results must meet the specified requirements.A 600Inspection601 Materials are subject to visual inspection, non-destruc-tive testing (NDT) and measurements of dimensions as detailed in B to D. The manufacturers shall prepare written procedures for NDT. NDT personnel shall be qualified and certified according to ISO 9712, EN 473, SNT-TC-1A or equivalent. NDT operators shall be qualified to at least level I. 602 NDT shall be performed in accordance with the general practice of recognised standards, e.g.:Magnetic particle testing (MT) of forgings:—EN 10228-1, ASTM A275, using wet continuous magnet-isation techniqueUltrasonic testing (UT) of forgings:—EN 10228-3, ASTM A388Magnetic particle testing (MT) of castings:—ASTM E709, using wet continuous magnetisation tech-niqueUltrasonic testing (UT) of castings:—ASTM A609603 MT of forged or cast accessories shall be carried out after proof load testing. Where a forging or casting is delivered in an intermediate condition for subsequent processing and final MT by the purchaser, the manufacturer should perform suitable intermediate inspections taking into consideration the quality level required in finished condition. In such cases the extent of testing and acceptance criteria shall be agreed between manufacturer and purchaser. See also C600, D600, and Sec.2 C.604 UT of forgings or castings shall be carried out at an appropriate stage after the final heat treatment for mechanical properties, e.g. after proof load testing of finished accessories.A 700Repair701 Surface defects may be removed by grinding as detailed in B to D. The resulting grooves shall have a bottom radius of approximately three times the depth and shall be blended into the surrounding surface to avoid any sharp contours. Complete elimination of the defective material shall be verified by suita-ble NDT.702 Except as provided for steel castings, repair by welding is not permitted.A 800Identification801 Each bar, forging, or casting shall be suitably identified with at least the following:a)identification number, heat number or other marking thatwill enable the history of the item to be traced,b)steel grade designation.A 900Records901 The manufacturer shall maintain traceable records of the following and present them to the purchaser on request:a)steelmaking process and chemical compositionb)heat treatmentc)mechanical testingd)inspectione)repair.B. Rolled Steel BarsB 100Scope101 These requirements are supplementary to A and apply to hot rolled steel bars to be used in the manufacture of offshore mooring chain and accessories.B 200Manufacture201 Bars shall be made from ingots or continuous cast blooms or billets. Ingots shall be cast in chill moulds with the larger cross-section up, and with efficient feeder heads. Suffi-cient discard shall be made to ensure soundness in the finished bar. Surface and skin defects, which may be detrimental during the subsequent working and forming operations, shall be removed.202 The rolling reduction ratio shall be at least 5:1. The roll-ing reduction ratio shall be calculated as the ratio average cross-sectional area of the cast material to cross-sectional area of the finished bar.B 300Chemical composition301 The chemical composition shall comply with the agreed specification.B 400Condition of supply and heat treatment401 Unless otherwise agreed, the bars shall be delivered in the as rolled condition.402 For mechanical testing and hydrogen embrittlement test-ing, bar material shall be tested in the condition of heat treat-ment used for the chain as advised by the chain manufacturer.B 500Mechanical testing501 A test unit shall consist of bars of the same nominal diameter, made from the same heat of steel, and with a total mass not exceeding 50 tonnes.502 Test material shall consist of a suitable length cut from one bar in each test unit. The test material shall be heat treated in full cross-section, see 402.503 For each test unit, one tensile and three Charpy V-notch test pieces shall be taken. For Charpy V-notch impact testing, the notch shall be cut in a face of the test piece which was orig-inally approximately perpendicular to the rolled surface.504 The mechanical properties shall comply with the values given in Table E1.B 600Hydrogen embrittlement testing601 For grade R3S, R4, R4S and R5, each heat of steel shall be tested for hydrogen embrittlement by slow strain rate tensile testing. Samples shall be taken from two bars representing the front end and tail end of the billet string in case of continuous casting, or two ingots in case of ingot casting.602 Two tensile test pieces shall be taken from the central region of each bar. The test pieces shall have a diameter of 20 mm, or alternatively 14 mm. One test piece shall be tested within three hours after machining for a 20 mm diameter test piece, or 1.5 hours for a 14 mm diameter test piece. The other test piece shall be tested after baking at 250°C for four hours for a 20 mm diameter test piece, or two hours for a 14 mm diameter test piece. The test pieces shall be loaded at a strain rate not exceeding 0.0003 per second until fracture occurs. 603 As an alternative to testing within the time limits given in 602 the test pieces may be cooled to –60°C immediately after machining and kept at that temperature for a maximum period of five days before testing.604 The reduction of area values shall be determined. The ratio Z1 to Z2, where Z1 is the value without baking and Z2 is the value after baking, shall not be less than 0.85. Alterna-tively, the ratio shall not be less than 0.80 provided Z1 is at least 50%.D ET N ORSKE V ERITASAmended October 2009Offshore Standard DNV-OS-E302, October 2008 see note on front cover Ch.2 Sec.1 – Page 15605 If the results do not meet the specified requirements, the bar material may be subjected to a hydrogen degassing treat-ment. The embrittlement tests shall be repeated after degassing and the results must meet the specified requirements.B 700Dimensions and tolerances701 The tolerances on diameter and roundness shall be in accordance with Table E2. Measurements shall be made on at least 1% of the bars.B 800Inspection801 All bars supplied in a machined (peeled) condition shall be visually inspected. All bars supplied without machining shall be tested for longitudinal imperfections by magnetic or electrical methods in accordance with the general practice of recognised standards.802 All bar material shall be subjected to ultrasonic testing at an appropriate stage of manufacture.803 All bars shall be free from injurious pipe, cracks, seams, laps or other imperfections which, due to their nature, degree or extent, will interfere with the use of the bars.B 900Repair901 Defects may be removed by grinding to a depth of 1% of the nominal bar diameter.C. Steel ForgingsC 100Scope101 These requirements are supplementary to A and apply to steel forgings to be used in the manufacture of chain accesso-ries. Additional requirements for the finished accessories are given in Sec.2 C.C 200Manufacture201 Forgings shall be made from ingots or continuous cast blooms or billets. Ingots for forgings shall be cast in chill moulds with the larger cross-section up, and with efficient feeder heads. Adequate top and bottom discards shall be made to ensure freedom from piping and harmful segregations in the finished forgings. Surface and skin defects, which may be det-rimental during the subsequent working and forming opera-tions, shall be removed.202 The material shall be progressively hot worked by ham-mer or press, and shall be forged as close as practical to the fin-ished shape and size.203 The reduction ratio shall be calculated with reference to the average cross-sectional area of the cast material. Where an ingot is initially upset, this reference area may be taken as the average cross-sectional area after this operation. The total reduction ratio shall be at least 3:1. For forgings made by upsetting, the length after upsetting is to be not more than one-third of the length before upsetting or, in the case of an initial forging reduction of at least 1.5:1, not more than one-half of the length before upsetting.204 Welding to forgings is not permitted. This includes the welding of brackets, bosses, or attachments.C 300Chemical composition301 The chemical composition shall comply with the agreed specification.C 400Heat treatment401 Forged accessories in grade R3 and R3S shall be sup-plied in the normalised, normalised and tempered, or quenched and tempered condition. Grade R4, R4S and R5 shall be sup-plied in the quenched and tempered condition. Quenched and tempered accessories with diameter over 120 mm shall receive an annealing or normalising heat treatment prior to quenching and tempering.402 For grade R4, R4S and R5, tempering temperatures shall not be less than 590°C and cooling after tempering shall be in water.403 Where forgings are to be quenched and tempered and cannot be hot worked close to shape, they shall be rough machined prior to being subjected to this treatment.404 All hot forming operations shall be conducted prior to the final heat treatment. If a forging is subsequently heated for further hot forming, the forging shall be re-heat treated.C 500Mechanical testing501 Forged accessories shall be mechanically tested as given in Sec.2 C.C 600Inspection601 All forgings shall be visually inspected on accessible surfaces. Where applicable, this is to include the inspection of internal surfaces and bores. The surfaces shall be adequately prepared for inspection. Black forgings shall be suitably de-scaled.602 Forgings shall be free from injurious pipe, cracks, seams, laps or other imperfections which, due to their nature, degree or extent, will interfere with the use of the forgings. 603 All finished accessories are subject to magnetic particle testing, see A600 and Sec.2 C.604 Ultrasonic testing shall be carried out on all forgings after the final heat treatment when the surfaces have been brought to a condition suitable for UT. Both radial and axial scanning shall be used when appropriate for the shape and dimensions of the forging being tested. Unless otherwise agreed with the purchaser the entire volume of the forgings shall be tested.605 For calibration, reference blocks shall be made from steel that is similar in chemistry and processing history to the production forgings. The distance amplitude curve (DAC) shall be based on 3 mm flat bottom hole. No indications equal to or larger than the reference DAC are acceptable.C 700Repair701 Defects on non-machined surfaces may be removed by grinding to a depth of 5% of the nominal diameter. Grinding is not permitted on machined surfaces, except for slight inspec-tion grinding on plane surfaces in order to investigate spurious indications. Welding and weld repairs are not permitted.D. Steel CastingsD 100Scope101 These requirements are supplementary to A and apply to steel castings to be used in the manufacture of chain accesso-ries. Additional requirements for the finished accessories are given in Sec.2 C.D 200Manufacture201 Castings shall be manufactured according to drawings showing the positions of gates, risers and chills (if used). 202 Where flame cutting, scarfing or arc-air gouging to remove surplus metal is undertaken, the affected areas shall be either machined or ground smooth.D 300Chemical composition301 The chemical composition shall comply with the agreed specification.D ET N ORSKE V ERITAS。
挪威船级社规范DNV2005
挪威船级社船板规范（DNV：2005）第二部分第二章第一节结构用轧制钢材A通则A100 适用范围101本节规定了可焊接普通强度、高强度和超高强度结构用轧制钢板和型钢的要求，这些要求也适用于结构用无缝钢管。
本要求适用于厚度不超过150mm的钢材产品。
对于更厚的钢材按每一情况考虑后可接受或要求与本规范有某些不同的规定。
本节包含了IACS UR W11和W16的规定。
对用轧制扁坯、方坯或圆钢作为锻件代替品的要求见第5节。
102在化学成分、脱氧方法、供货状态和机械性能与本规范要求有所不同的钢材,只要经本船级社专门认可也可予以接受。
这些钢材应给予特殊符号，见200。
A200 钢材等级符号201本节钢材等级按强度等级划分为三组----普通强度钢（NS）----高强度钢（HS）----超强度钢（EHS）202钢材等级的字母数字标记为NV xy。
其中：NV—按本社规范规定的钢材等级符号X—大写字母表示的相应于规定的冲击试验温度，见表A1。
Y—按标定最小屈服强度确定的强度组别数字符号，见表A1。
对NS钢该数字可省略。
203在202规定的字母数字符号后的附加符号可以是：Z—改进厚度方向性能的钢材等级。
S—专门认可的钢材，见100。
A300制造方法301钢用碱性吹氧炼钢工艺、电炉工艺生产，经本社批准，也可用其它方法生产。
302从连续浇铸的扁坯轧成板材的板厚减薄率除非本社另行认可，最小值为5：1。
303适用的轧制方法定义如下：控制轧制CR（正火轧制NR）：在正火温度范围内进行的最终成型的轧制过程。
所得到的材质状态，通常相当于经正火后的结果。
热机轧制TM（热机控制法TMCP）：这是一种必须严格控制钢材温度和轧制减薄量的方法。
通常在接近AR3温度下实施高比例的轧制减薄量，并可在两相区域内进行轧制。
不同于控制轧制法（正火轧制），TM具有的性能不可能由随后的正火或其他热处理方法再生产。
B普通强度钢B100适用范围101本条规定了普通强度钢的要求，最小屈服强度为235N/mm2的钢材定为普通强度钢。