不锈钢钝化处理标准

ED CB AFIRST ISSUE12/09/2008SCSCRevNATURE OF REVISIONDATEMADEAPPROVEDSHOUGANG JINGTANG United Iron & Steel Co., Ltd. Seawater Desalination Project Phase I-2 2 x 7 T/E 12500Contract N° JTHD-JS-01Name Date VisaMade CHARLES 12/09/08 Checked CHARLES 12/09/08 Approved CHARLES 12/09/0820-22, RUE DE CLICHY 75009 PARIS ' 33 (0) 1 49 95 76 76 – 7 33 (0) 1 49 95 76 95e-mail : sidem-paris@DENOMINATIONPAGE1/8FORMATA4SPECIFICATION FOR STAINLESS STEELPASSIVATION TREATMENT084020 – 0000H407 REV.This document is SIDEM property it cannot be used, reproduced, transmitted and/or disclosed, without prior written permission.Original document n° : 541001 08005-KS-0024-00.docCONTENTS1.INTRODUCTION (3)2.PRE CLEANING & DEGREASING (3)3.PICKLING & PASSIVATION TREATMENT IN BATH (4)4.TREATMENT WITH PICKLING & PASSIVATING PASTES (4)4.1P ICKLING WITH PASTE (4)4.2P ASSIVATION WITH PASTE (4)5.TREATMENT BY SPRAYING (4)6.APPROVED PRODUCTS & SUPPLIERS (5)7.SURFACES TO BE TREATED (7)8.RESULTS TO BE OBTAINED & QUALITY CONTROL (7)8.1V ISUAL I NSPECTION (7)8.2F ERROXYL TEST (7)9.PRECAUTIONS TO BE TAKEN (8)10.PRECAUTION AFTER PASSIVATION (8)1. INTRODUCTIONThe purpose of stainless steel passivation treatment is to develop a thin film of chromium oxide on the surface of plates and weld beads, which enhance the corrosion resistance of these steels.Passivation shall be also a mean of decontamination, i.e. it shall eliminate any ferrous particles that may have been deposited on plates and weld beads (due to cutting or forming, tools friction, wire brushing, etc.).Pickling applied before passivation treatment, eliminates all pollutants and selectively remove the least corrosion-resistant areas at the surface of the steel.For the treatment to be effective, all traces of organic contaminants, grease or oils shall be removed. Therefore a pre-cleaning is compulsory before pickling and passivation.Hence the sequence of operations is typically:- Pre-cleaning / Degreasing ;- First rinsing ;- Pickling ;- Second rinsing ;- Passivation / decontamination ;- Final rinsing and drying.As a general rule, products shall preferably be sprayed.Meanwhile treatment by dipping in a bath may be advantageously considered for small vessels or piping parts.Treatment with paste may be preferred for small areas (weld beads, repairs) or when spraying may be detrimental to some materials (for instance heat exchange surfaces of already tubed exchangers).The fabrication shops are required to establish a written procedure, based on the rules set force by this specification. Such procedure shall be submitted to SIDEM for approval.Important note:Products used for passivation shall contain no hydrochloric acid, nor any chloride.At a too low temperature the pickling and passivation products may be ineffective. The treatment shall be carried out at a high enough room temperature (>10°C.) In any case the suppliers instructions shall be followed.The water used for all the phases of the treatment, for the preparation of baths and the dilution of products as well as rinsing, shall be clean and have a low chloride content of (in principle, maximum 30 ppm.)2. PRE CLEANING & DEGREASINGIn order to have an effective pickling and passivation, it is necessary to remove from the surface all organic contaminants, such as grease oil paint and dirt.Organic contaminants hinder the action of pickling and passivation products, and are potentially dangerous because they may initiate pitting corrosion.The recommended products are generally based on phosphoric acid (possibly sulfamic) with surfactant and solvent diluted in water.The pre-cleaning product is sprayed on the surface to be cleaned and degreased. It is necessary to rinse heavily afterward, preferably with high-pressure water jet, which improves the quality of the treatment.To check the effectiveness of the pre-cleaning apply the method of the water film (ref to § 8.)3. PICKLING & PASSIVATION TREATMENT IN BATHAfter pre-cleaning and degreasing :1) First the piece of equipment shall be dipped into (or filled with) a solution prepared as follows:- Nitric acid 36° Be 100 litres.- 65% hydrofluoric acid or 20 litres- Sodium fluoride 20 kg- Water 900 litres.2) Keep the piece of equipment submerged for 10 minutes if the solution is heated up to 60°C or for 2hours if the solution is at room temperature.3) Rinse quickly with water until the pH of the effluents is equal to the pH of the incoming water.4) The piece of equipment shall again be dipped into (or filled with) another solution:- Nitric acid 36° Be 250 litres.- Water 750 litres.5) Keep the piece of equipment submerged :- For 15 minutes if the solution is heated to 50°C.- For 2 hours if the solution is at room temperature.6) Rinse quickly with water until the pH of the effluent is equal to the pH of the incoming water.4. TREATMENT WITH PICKLING & PASSIVATING PASTESPickling and passivating pastes are used to the treatment of limited areas, such as weld beads and heat affected zones and when a bath treatment or by spraying is too heavy to be considered, or impossible.They are particularly adapted to local treatment after repair, or during maintenance of units in commercial operation.4.1 Pickling with paste.Pastes for pickling stainless steels consist of a mixture of nitric and hydrofluoric acid with binders.Apply the paste on the weld beads with an acid resisting brush, and rub vigorously with a stainless steel wire brush.Rinse afterward with a high-pressure water jet before the paste is dry.4.2 Passivation with paste.Pastes for passivating stainless steels contains nitric acid only mixed with bindersApply a uniform layer of passivating paste over all the previously pickled areas with an acid resisting brush. Allow the paste to act during 3 to 4 hours, and then rub gently with a nylon brush.Rinse with a high-pressure water jet before the paste is dry. Then dry the surface.5. TREATMENT BY SPRAYINGSpay pickling solutions and gels, are composed of mainly a mixture of nitric acid (20 to 25 %) hydrofluoric acid (around 5%) with binders and surfactants in order to have a correct viscosity and thixotropySpray passivation solutions and gels have a similar composition, but without hydrofluoric acid.The procedure is as follows :1) PicklingAfter thorough pre-cleaning / degreasing, as described in §2, spray on a dry surface a uniform layer of products with an adapted acid resistant equipment.Let the product act during the necessary time, following the instructions of the supplier. If necessary, heavily tinted weld beads and heat affected zones, shall be vigorously rubbed with a stainless steel wire brush to remove any trace of coloration.Rinse thoroughly with a high-pressure water jet, dry and check that no residues remain at the surface.2) Passivation.After pickling, and immediately after the rinsing, spray on a dry surface a uniform layer of product, with an adapted acid resistant equipment.Let the product act during the necessary time, following the instructions of the supplier rubbing if necessary weld beads and heat affected zones.Rinse thoroughly with a high-pressure water jet, and check that no residues remain at the surface.Dry completely the treated surfaces.6. APPROVED PRODUCTS & SUPPLIERSSUPPLIERS PRE-CLEANINGPRODUCTSPASTES and BRUSHAPPLICATIONSPRAY SOLUTIONS ANDGELSPickling Passivation Pickling PassivationAVESTA Avesta Cleaner401Avesta 101 Avesta 204 Avesta 601CHEMETALL (Oakite) Antox 75E Antox 71 E Antox 98F Antox 73E Antox 98FCHIMIMECA Prosolv 500/510NZedinox / ZED+Prociv 300PN Procap Pro Prociv 300CHIMIDEROUIL FINOX DH /FINOX DHNGel Inox SCDR 1117Fluidox CR66CDR 1049COOLMIN Coolmin S20 Coolmin ESP Coolmin ESP100DERUSTIT 3023 3041 ou 4020 2016 4021 2016PELOX PELOX FRD PELOX TSExtraPELOX RP PX SPK Extra PELOX RPPOLIGRAT DecapoliOpaleDecapoli 67SURFACE INNOVATORS K2 Paste form K2 SprayFormK2PassivationAVESTAAvesta Welding AB, Chemical division, Hanögatan 2B, SE-211 24 Malmöe SwedenTel +46 (0) 40 93 94 30. Fax +46 (0) 40 93 94 24DBP 28, rue Francisco Ferrer, BP 251 69152 Décines CEDEX. France.Tel +33 (0)4 37 25 17 40DBPAV@wanadoo.frCHEMETALLChemetall Traitement de surface SA 51, rue Pierre - BP 310 92111 Clichy Cedex. FranceTel. : + 33 (0)1 47 15 38 00. Fax : + 33 (0)1 47 37 46 60.www.chemetall.fr / CHIMIMECAChimimeca 2D, ZI Mi-Plaine 40, rue Ampère, 69680 Chassieu, France.Tel +33 (0)4 72 47 57 04. Fax +33 (0)4 78 90 85 83.CHIMIDEROUILRue Aimé Dubost BP 37 62670 Mazingarbe FranceTel : + 33 (0)3 21 72 84 94 Fax : + 33 (0)3 21 72 84 93.COOLMINHankuk Coolmin Chemical Co LTD. KoreaDERUSTITDeutsche Derustit GmbH Emil-von-Behring-Str. 4D-63128 Dietzenbach GermanyTel.: + 49 6074 4903 0. Fax: + 49 6074 4903 33info@derustit.deScherdel Soudure S.A. B.P. 221 F-57005 Metz Cedex FranceTel : + 33 (0)3 87 64 53 70. Fax + 33 (0)3 87 66 53 52PELOXGesa Soudure 13, allées des Cyprès – BP 226, 57604 Forbach Cedex France.PELOX – Chemietechnic GMBH & CO. KG. D-3012 Langenhagen/Hannover Klusriede 16 GermanyTel : 05 11 732003-04. Fax 05 11 733993POLIGRATPOLIGRAT France Sud2, rue Saint-Éloi B.P. 78 F 71300 Montceau-Les-Mines Cedex FranceTel + 33 (0)3 85 67 99 99 Fax + 33 (0)3 85 67 99 88poligrat@poligrat.frPOLIGRAT France Nord Z.I. Villers-St Paul F 60870 RIEUX FRANCETel : + 33 (0)3 44 71 71 72 Fax : + 33 (0)3 44 71 64 18polimet@poligrat.frPOLIGRAT GMBH Valentin-Linhof-Straße 19 D-81829 München GermanyTel : 089 / 42778-0 Fax: 089 / 42778-309info@ / www.poligrat.deSURFACE INNOVATORSUnique Industrial Estate, Gala N°24, Golani Industrial Complex, Vasai (E), Thane- 401 208 Maharashtra. IndiaTel : 892 1839 Fax : 891 4691 / 497 53507. SURFACES TO BE TREATEDAs a minimum requirement pickling followed with a passivation treatment shall compulsorily be applied:- On the bottom plates of evaporators and the vertical walls and/or the cylindrical shell up to the first level of demisters.- On all internal surfaces of seawater and brine pipework.- On all the weld beads and heat affected zones.It is accepted that the external sides of the welds are not to be treated if they are blasted before applyinga painting system.- On all internal surfaces of condensers water boxes.- On all internal surfaces of deaerators, chemical tanks and sea water filters.In all cases before applying the treatment, heat exchanger tubes shall be carefully protected against a possible aggression from the products, which are used.It is mandatory to apply cleaning, pickling and passivation treatment at shop, before delivery of fabricated equipments.Even so, before commissioning, after initial operation, and regularly during the lifetime of the plant, it is recommended to inspect all the treated surfaces and renew the treatment on zones that are tinted or showing evidence of incipient corrosion.8. RESULTS TO BE OBTAINED & QUALITY CONTROLSubcontractors carrying out pickling and passivation treatment at shop or at site, shall fill a report on the various operations of pre-cleaning / degreasing, pickling, passivation, and the results obtained for each.For each operation, the trade names of the products being used, possibly the dilution, the method of application and the time of action shall be recorded.The final inspection shall be carried out at least 2 days after the pickling and passivation treatment.8.1 Visual InspectionAfter pre-cleaning / degreasing, the surface shall be completely free of any grease or organic compound, and that is to be checked with the water film method: A thin layer of water applied at the surface will break around any contaminated area.All passivated surfaces shall have a "white metal" appearance.To perform the inspection a powerful lighting shall be installed (1000 lx is recommended).8.2 Ferroxyl testThis test is very sensitive and detects even traces of ferrous particles. It shall be conducted on a perfectly clean metal.Tinted or doubtful areas shall be checked with "Ferroxyl Test for free iron".In addition to doubtful areas, 1% at least of treated surfaces shall be random checked with the "Ferroxyl Test", as directed by SIDEM Inspector. Welds, HAZ and back of stiffeners welds, shall be checked in priority.Warning: Do not conduct this test on distillate side of Evaporators."Ferroxyl/Test" Method :The procedure is described in ASTM A 380.Prepare a test solution by mixing the following ingredients:- Distilled water : 94% (1000 cm³)- Nitric acid 60-67% : 3% (20 cm³)- Potassium Ferricyanide : 3% (30g)Clean the surface with a clean cloth and demineralised water.Apply the solution using a spray applicator, which shall have no steel parts.Contamination is indicated by the appearance of a greenish blue colour after few minutes. Yellow colour indicates a non-contaminated passivated area.The solution shall be removed immediately after reading with a demineralised water spray and a damp cloth. All traces of the testing product shall be removed.Any contaminated surface shall be passivated again.In the case where contaminated areas (greenish blue) are too numerous, the extent of the test may be increased, as directed by SIDEM inspector.9. PRECAUTIONS TO BE TAKENAll these products being acid and certainly dangerous; the operators shall protect themselves with mask, goggles, rubber gloves, apron and boots.A suitable air supply and venting shall be maintained.In any case, supplier instructions shall be carefully followed.Potassium ferricyanide is not a dangerous poison as are the simple cyanides. However, when heated to decomposition or in contact with concentrated acid, it emits highly toxic cyanides fumes.The whole procedure of cleaning, pickling and passivation will be rendered ineffective if the air around is contaminated by dust, carbons steel or grease and organic particles.A thorough cleanliness shall be maintained throughout the procedure. If necessary, the equipments shall be protected from the contaminated atmosphere by suitable means.10. PRECAUTION AFTER PASSIVATIONTo avoid any contamination of the newly passivated areas, the vessels shall immediately be closed after control is completed.For any necessary work inside the vessel, personal shall use clean tennis shoes - or protective sleeves on shoes – and cloths.。