焊接手册
焊接手册(ASME规范)
压力容器焊接手册(ASME 规范)
目录
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2 第 2 页，共 104 页
压力容器焊接手册(ASME 规范)
1.1 目的 作为焊接 ASME 规范容器的参考基准。
第一章 总则
1.2 适用范围 本手册适用于按照 ASME 规范建造的压力容器焊接的设计、采购、检验等。
1.3 参考文献 1）ASME 规范第 VIII－1 卷。 2）ASME 规范第 VIII－2 卷。 3）ASME 规范第 IX 卷。 4）ASME 规范第 II-C 卷。
Joint Design 接头
(10)
Backing (Yes) 衬垫（有） (11)
(No)（无）
Backing Material (Type) 衬垫材料（型号）
(12)
(Refer to both backing and retainers)
□Metal
□Nonfusing Metal
□Nonmetallic
压力容器焊接手册(ASME 规范)
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DHME
压力容器焊接手册(ASME 规范)
第 1 页，共 104 页
焊接科－焊接技术系 2007 年
1
第一章 总则 1.1 目的 1.2 适用范围 1.3 参考文献 第二章 设计规范 2.1 编制 WPS 2.2 评定 PQR 2.3 设备焊接坡口设计 第三章 采购要求 3.1 焊接材料采购技术要求 3.2 焊接材料选择指南
压力容器焊接手册(ASME 规范)
版次：0
POSITION QW-405 焊接位置 Position(s) of Groove 坡口的位置 Welding Progression: Up 向上 Position(s) of Fillet 角焊缝位置
marc焊接教材
marc焊接教材
以下是一些关于MARC焊接的参考教材和资料：
1. "MARC Welding Manual" - 由MARC (Metal Active Gas Arc Welding) Welding Institute出版的焊接手册，提供了MARC焊接的详细信息和操作指导。
2. "Gas Metal Arc Welding Handbook" by William H. Minnick - 这本书介绍了气体金属弧焊 (GMAW) 或称为MARC 焊接的原理、设备、材料和技术，适合初学者和专业人士阅读。
3. "The Procedure Handbook of Arc Welding" by Lincoln Electric - 这本书是一本焊接手册，包含了各种弧焊方法和技术，其中也包括了MARC焊接的基本概念和应用。
4. "Welding Principles and Applications" by Larry
F. Jeffus - 这本书是针对焊接的基本原理和应用的综合性教材，其中也讲解了MARC焊接的基本知识和技术。
此外，还可以参考相关的国家和国际标准，如美国焊接
学会（American Welding Society）的标准和指南，其中也包括了MARC焊接的相关内容。
需要注意的是，MARC焊接是一种具体的焊接过程，在学习和实践时应遵循相关的安全操作和工艺规程。
建议在学习和实践焊接技术时，尽量结合理论和实践，同时跟随合适的教师或专业人士指导，以确保安全和正确认识焊接过程。
焊接手册
焊接技术人员培训手册第一部分焊接工艺评定的使用管理&焊接工艺规程的编制一、焊接工艺评定的有关概念二、焊接工艺评定及使用管理程序三、焊接工艺评定变素及其评定规则四、如何阅读焊接工艺评定报告五、如何编制焊接工艺规程一、焊接工艺评定的有关概念1、焊接工艺评定的定义和目的2、消除焊接工艺评定认识上误区：3、“焊接性能”与“焊接性”4、“焊接性能试验”与“焊接工艺评定”5、“焊缝”与“焊接接头”6、“焊接工艺评定”与“焊工技能考试”7、焊接工艺评定的基本条件8、常用焊接工艺评定标准：JB4708－2000《钢制压力容器焊接工艺评定》GB50236－98《现场设备、工业管道焊接工程施工及验收规范》第4章劳部发1996[276]号《蒸汽锅炉安全监察规程》附录IJGJ81-2000《建筑钢结构焊接技术规程》第5章GB128-90《立式圆筒形钢制焊接油罐施工及验收规范》附录一ASME第IX卷《焊接与钎焊》二、焊接工艺评定及使用管理程序1、焊接工艺评定程序（1）焊接工艺评定立项（2）焊接工艺评定委托（3）编制焊接工艺指导书（WPI）并批准（4）评定试板的焊接（5）评定试板的检验焊接工艺评定失败，重新修改焊接工艺指导书，重复进行上述程序。
（6）编写焊接工艺评定报告（PQR）并批准2、焊接工艺评定文件的使用与管理（1）焊接工艺评定文件的受控登记。
（2）焊接工艺评定的有效版本及换版转换。
（3）每季度编制焊接工艺评定文件的有效版本目录。
（4）保证现场工程和产品的焊接工艺评定的覆盖率为100%。
（5）焊接工艺评定文件作为公司的一项焊接技术储备，属于公司重要技术机密文件，应妥善保管。
三、焊接工艺评定变素及其评定规则1、焊接工艺评定的主要变素：试件形式母材类别焊接方法焊接工艺因素焊后热处理种类及参数母材厚度焊缝熔敷金属厚度四、如何阅读焊接工艺评定报告1、如何认识焊接工艺评定报告的作用（1）焊接工艺评定报告的合法性：（2）焊接工艺评定报告的有效性：（3）焊接工艺评定报告及焊接工艺规程的局限性：（4）焊接工艺评定报告是一种必须由企业焊接责任工程师和总工程师签字的重要质保文件，也是技术监督部门和用户代表审核施工企业质保能力的主要依据之一。
激光焊接手册
Some boundary conditions as to materials and product design have to be fulfilled. The most important condition to the materials is that one product part should be transparent for laser radiation, whereas the other part has to be absorbent. As regards product design, the most important aspect is the geometry of the weld region. A large number of shapes can be used to obtain an optimum welding result. This publication describes the potential of polymer laser welding and presents information on product design, materials, process parameters and equipment. Attention is also given to the latest developments in the area of diode-lasers. This new type of laser is particularly attractive because of its interesting price/performance ratio. Their optical beam quality is somewhat less compared to conventional laser systems, but this is usually no disadvantage at all in case of polymer welding. Finally, the usage of the process is illustrated by means of a number of (potential) applications. These involve varying industrial areas. Product sizes range from the very small to the very large: - Miniature components for optical information storage - Miniature products for biomedical applications - Encapsulation of electronic components - Housings of personal electronic products - Automotive components - Double-walled window systems.
英文焊接手册Welding handbook
Document provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call 1the Document Policy Group at 303-397-2295.2NOTE:Although care was taken in choosing and presenting the data in this guide, AWS cannot guarantee that it iserror free. Further, this guide is not intended to be an exhaustive treatment of the topic and therefore may not include all available information, including with respect to safety and health issues. By publishing this guide, AWS does not insure anyone using the information it contains against any liability or injury to property or persons arising from that use.© 2004 by American Welding Society. All rights reserved.Printed in the United States of AmericaCopyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---The inspection requirements for the fabrication and welding of steel structures are very extensive. This PocketHandbook has been developed to provide a useful tool for inspectors to carry in their pockets or tool kits so that selected pertinent portions of the AWS Structural Welding Code—Steel, D1.1/D1.1M:2004, can be easilyreferenced at the job site. Underlining is as shown in the code.This publication is not to be considered as a substitute for the D1.1 code book. Rather, the Handbook is providedas a supplemental aid for the “deckplate” inspector. Only the complete code should be considered as the officialdocument to ensure that all of the quality attributes required for structural fabrication are performed correctly and completely.To assist the inspector, or other user, in verifying conformance to D1.1, the paragraph references, the table num-bers, and the figure numbers contained in this book are directly from the D1.1/D1.1M:2004 code. In addition, page numbering in this handbook is cross-referenced to reflect both the current page and the corresponding page from the D1.1/D1.1M:2004 code, separated by a “/.” This will provide an easy cross reference for the user to ensure that the complete requirements are understood when questions develop during the course of any inspection.IntroductionCopyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---3Requirements for Transitions Between Materials of Unequal Thickness (5)Thermal Cutting and Access Hole Requirements (9)Tolerance of Joint Dimensions (13)Dimensional Tolerances of Welded Structural Members (19)Base Material Surface Requirements (25)Weld Profile Requirements (26)Acceptance Criteria for Visual Inspection of Welds (32)Index (37)Table of ContentsCopyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---45Figure 2.21—Transition of Thickness of Butt Joints in Parts ofUnequal Thickness (Tubular) (see 2.25 [pg. 22])Requirements for Transitions Between Materials of Unequal Thickness5/pg. 55Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please callthe Document Policy Group at 303-397-2295.-6Figure 2.21 (Cont’d)—Transition of Thickness of Butt Joints in Parts ofUnequal Thickness (Tubular) (see 2.25 [pg. 22])Requirements for Transitions Between Materials of Unequal Thickness6/pg. 55Copyright American Welding Society Provided by IHS under license with AWS Document provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--7(see 2.7.1 [pg. 10] and 2.16.1.1 [pg. 14])Requirements for Transitions Between Materials of Unequal Thickness7/pg. 42Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please callthe Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---8Figure 2.12—Transition of Width (Cyclically Loaded Nontubular) (see 2.16.1.2 [pg. 14])Requirements for Transitions Between Materials of Unequal Thickness8/pg. 48Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,95.15.4.3Roughness Requirements. In thermal cutting, the equipment shall be so adjusted and manipulated as to avoid cutting beyond (inside) the prescribed lines. The roughness of all thermal cut surfaces shall be no greater than that defined by the American National Standards Institute surface rough-ness value of 1000 µin. [25µm] for material up to 4in. [100 mm] thick and 2000µin. [50 µm] for mate-rial 4 in. to 8 in. [200 mm] thick, with the following exception: the ends of members not subject to calcu-lated stress at the ends shall not exceed a surface roughness value of 2000 µin. ANSI/ASME B46.1,Surface Texture (Surface Roughness, Waviness, and Lay) is the reference standard. AWS Surface Rough-ness Guide for Oxygen Cutting (AWS C4.1-77) may be used as a guide for evaluating surface roughness of these edges. For materials up to and including 4 in.[100 mm] thick, Sample No. 3 shall be used, and for materials over 4 in. up to 8 in. [200 mm] thick,Sample No. 2 shall be used. 5.15.4.4Gouge or Notch Limitations. Rough-ness exceeding these values and notches or gougesnot more than 3/16 in. [5 mm] deep on other wise satisfactory surfaces shall be removed by machining or grinding. Notches or gouges exceeding 3/16 in.[5mm] deep may be repaired by grinding if the nominal cross-sectional area is not reduced by more than 2%. Ground or machined surfaces shall be fared to the original surface with a slope not exceeding one in ten. Cut surfaces and adjacent edges shall be left free of slag. In thermal-cut surfaces, occasional notches or gouges may, with approval of the Engi-neer, be repaired by welding.5.16Reentrant CornersReentrant corners of cut material shall be formed to provide a gradual transition with a radius of not less than 1 in. [25 mm]. Adjacent surfaces shall meet without offset or cutting past the point of tangency.Thermal Cutting and Access Hole Requirements9/pg. 185Copyright American Welding SocietyProvided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please callthe Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---10The reentrant corners may be formed by thermal cut-ting, followed by grinding, if necessary, to meet the surface requirements of 5.15.4.3.5.17Beam Copes and Weld AccessHolesRadii of beam copes and weld access holes shall provide a smooth transition free of notches or cutting past the points of tangency between adjacent surfaces and shall meet the surface requirements of 5.15.4.3.5.17.1Weld Access Hole Dimensions. All weld ac-cess holes required to facilitate welding operations shall have a length (A ) from the toe of the weld preparation not less than 1-1/2 times the thickness of the material in which the hole is made. The height (h)of the access hole shall be adequate for depo-sition of sound weld metal in the adjacent plates and provide clearance for weld tabs for the weld in thematerial in which the hole is made, but not less than the thickness of the material. In hot rolled shapes and built-up shapes, all beam copes and weld access holes shall be shaped free of notches or sharp re-entrant corners except that when fillet web-to-flange welds are used in built-up shapes, access holes may terminate perpendicular to the flange. Fillet welds shall not be returned through weld access holes (see Figure 5.2).5.17.2Group 4 and 5 Shapes. For ASTM A6Group 4 and 5 shapes and built-up shapes with web material thickness greater than 1-1/2 in. [40 mm], the thermally cut surfaces of beam copes and weld access holes shall be ground to bright metal and inspected by either MT or PT. If the curved transition portion of weld access holes and beam copes are formed by pre-drilled or sawed holes, that portion of the access hole or cope need not be ground. Weld access holes and beam copes in other shapes need not be ground nor inspected by MT or PT.10/pg. 185Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---11Figure 5.2—Weld Access Hole Geometry (see 5.17.1 [pg. 185])11/pg. 196Copyright American Welding Society Provided by IHS under license with AWS Document provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please callthe Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---12General Notes:For ASTM A 6 Group 4 and 5 shapes and welded built-up shapes with web thickness more than 1-1/2 in. [40 mm], preheat to 150°F [65°C] prior to thermal cutting, grind and inspect thermally cut edges of access hole using MT or PT methods prior to making web and flange splice groove welds.These are typical details for joints welded from one side against steel backing. Alternative joint designs should be considered.Notes:1.Radius shall provide smooth notch-free transition; R ≥ 3/8 in. [10 mm] (Typical 1/2 in. [12 mm]).2.Access hole made after welding web to flange.3.Access hole made before welding web to flange. Weld not returned through hole.4.h min = 3/4 in. [20 mm] or t w (web thickness), whichever is greater.Figure 5.2 (Cont’d)—Weld Access Hole Geometry (see 5.17.1 [pg. 185])12/pg. 196Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---135.22.1Fillet Weld Assembly. The parts to be joined by fillet welds shall be brought into as close contact as practicable. The root opening shall not exceed 3/16in.[5mm] except in cases involving either shapes or plates 3 in. [75 mm] or greater in thickness if, after straightening and in assembly, the root opening cannot be closed sufficiently to meet this tolerance. In such cases, a maximum root opening of 5/16 in. [8 mm]may be used, provided suitable backing is used. Back-materials, or welds using a low-hydrogen process compatible with the filler metal deposited. If the sepa-ration is greater than 1/16 in. [2 mm], the leg of the fillet weld shall be increased by the amount of the root opening, or the contractor shall demonstrate that the required effective throat has been obtained.5.22.1.1Faying Surface. The separation be-tween faying surfaces of plug and slot welds, andof butt joints landing on a backing, shall not exceed 1/16 in. [2 mm]. Where irregularities in rolled shapes occur after straightening do not allow contact within the above limits, the procedure necessary to bring the material within these limits shall be subject to the approval of the Engineer. The use of filler plates shall be prohibited except as specified on the drawings or as specially approved by the Engineer and made in accordance with 2.13.5.22.2PJP Groove Weld Assembly. The parts to be joined by PJP groove welds parallel to the length of the member shall be brought into as close contact as practicable. The root opening between parts shall not exceed 3/16 in. [5 mm] except in cases involving rolled shapes or plates 3 in. [75 mm] or greater in thickness if, after straightening and in assembly, the root opening cannot be closed sufficiently to meet this tolerance. In such cases, a maximum root opening of 5/16 in. [8 mm] may be used, provided suitable back-ing is used and the final weld meets the requirements Tolerance of Joint Dimensions13/pg. 187Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---14for weld size. Tolerances for bearing joints shall be in conformance with the applicable contract specifications.5.22.3Butt Joint Alignment. Parts to be joined at butt joints shall be carefully aligned. Where the parts are effectively restrained against bending due to eccentricity in alignment, the offset from the theoreti-cal alignment shall not exceed 10% of the thickness of the thinner part joined, or 1/8 in. [3 mm], which-ever is smaller. In correcting misalignment in such cases, the parts shall not be drawn in to a greater slope than 1/2 in. [12 mm] in 12 in. [300 mm]. Mea-surement of offset shall be based upon the centerline of parts unless otherwise shown on the drawings.5.22.3.1Girth Weld Alignment (Tubular).Abutting parts to be joined by girth welds shall be carefully aligned. No two girth welds shall be located closer than one pipe diameter or 3 ft [1 m], whichever is less. There shall be no more than two girth welds in any 10 ft [3 m] interval of pipe, except as may be agreed upon by the Owner and Contractor. Radial offset of abutting edges of girth seams shall not exceed 0.2t (where t is the thickness of the thinner member) and the maximum allowable shall be 1/4 in.[6 mm], provided that any offset exceeding 1/8 in.[3mm] is welded from both sides. However, with the approval of the Engineer, one localized area per girth seam may be offset up to 0.3t with a maximum of 3/8 in. [10 mm], provided the localized area is under 8t in length. Filler metal shall be added to this region to provide a 4 to 1 transition and may be added in conjunction with making the weld. Offsets in excess of this shall be corrected as provided in 5.22.3.Longitudinal weld seams of adjoining sections shall be staggered a minimum of 90°, unless closer spacing is agreed upon by the Owner and Fabricator.5.22.4Groove Dimensions5.22.4.1Nontubular Cross-Sectional Variations.With the exclusion of ESW and EGW, and with the exception of 5.22.4.3 for root openings in excess of those permitted in Figure 5.3, the dimensions of the cross section of the groove welded joints which vary from those shown on the detail drawings by more than these tolerances shall be referred to the Engineer for approval or correction.14/pg. 187Copyright American Welding SocietyProvided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---155.22.4.2Tubular Cross-Sectional Variations.Variation in cross section dimension of groove welded joints, from those shown on the detailed drawings,shall be in accordance with 5.22.4.1 except:(1)Tolerances for T-, Y-, and K-connections are included in the ranges given in 3.13.4.(2)The tolerances shown in Table 5.5 apply to CJP tubular groove welds in butt joints, made from one side only, without backing.5.22.4.3Correction. Root openings greater than those permitted in 5.22.4.1, but not greater than twice the thickness of the thinner part or 3/4 in. [20 mm],whichever is less, may be corrected by welding to acceptable dimensions prior to joining the parts by welding.5.22.4.4Engineer’s Approval. Root openings greater than allowed by 5.22.4.3 may be corrected by welding only with the approval of the Engineer.5.22.5Gouged Grooves. Grooves produced by gouging shall be in substantial conformance with groove profile dimensions as specified in Figure 3.3and 3.4 and provisions of 3.12.3 and 3.13.1. Suitable access to the root shall be maintained.15/pgs. 187–188Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---16Figure 5.3—Workmanship Tolerances in Assembly of Groove Welded Joints (see 5.22.4.1 [pg. 187])16/pg. 197Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---17Root Not BackgougedRoot Backgouged in.mm in.mm(1)Root face of joint ±1/162Not limited (2)Root opening ofjoints without backing±1/162+1/16–1/8023Root opening of joints with backing +1/40–1/1662Not applicable (3)Groove angle ofjoint+10°–5°0+10°–5°0General Note: See 5.22.4.2 for tolerances for CJP tubular groove welds made from one side without backing.Figure 5.3 (Cont’d)—Workmanship Tolerances in Assembly of Groove Welded Joints (see 5.22.4.1 [pg. 187])17/pg. 197Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.18Table 5.5Tubular Root Opening Tolerances (see 5.22.4.2 [pg. 187])Root Face of Joint Root Opening of Joints without Steel Backing Groove Angle of Jointin.mm in.mm deg SMAW GMAW FCAW±1/16±1/32±1/16±2±1±2±1/16±1/16±1/16±2±2±2±5±5±5General Note: Root openings wider than allowed by the above tolerances, but not greater than the thickness of the thinner part,may be built up by welding to acceptable dimensions prior to the joining of the parts by welding.18/pg. 194Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---5.23Dimensional Tolerances of WeldedStructural MembersThe dimensions of welded structural members shall conform to the tolerances of (1) the general specifications governing the work, and (2) the special dimensional tolerances in 5.23.1 to 5.23.11.3. (Note that a tubular column is interpreted as a compression tubular member.)5.23.1Straightness of Columns and Trusses. For welded columns and primary truss members, regard-less of cross section, the maximum variation in straightness shall beLengths of less than 30 ft [9 m]:1 mm × No. of meters of total lengthLengths of 30 ft [10 m] to 45 ft [14 m] = 3/8 in. [10 mm]Lengths over 45 ft [15 m]:5.23.2Beam and Girder Straightness (No Cam-ber Specified). For welded beams or girders, regard-less of cross section, where there is no specifiedcamber, the maximum variation in straightness shallbe1 mm × No. of meters of total length5.23.3Beam and Girder Camber (TypicalGirder). For welded beams or girders, other than those whose top flange is embedded in concrete with-out a designed concrete haunch, regardless of cross1/8 in.No. of ft of total length10-------------------------------------------------------×3/8 in. + 1/8 in.No. of ft of total length – 4510--------------------------------------------------------------------×10 mm + 3 mmNo. of meters of total length – 153-------------------------------------------------------------------------------×1/8 in.No. of ft of total length10-------------------------------------------------------×Dimensional Tolerances of Welded Structural Members19/pg. 188Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please callthe Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---1920section, the maximum variation from required cam-ber at shop assembly (for drilling holes for field splices or preparing field welded splices) shall be at midspan,–0, +1-1/2 in. [40mm] for spans ≥100ft[30 m]–0, +3/4 in. [20 mm] for spans < 100 ft [30 m]at supports,0 for end supports± 1/8 [3 mm] for interior supports at intermediate points, –0, + wherea =distance in feet [meters] from inspectionpoint to nearest support S =span length in feet [meters]b =1-1/2 in. [40 mm] for spans ≥ 100 ft [30 m]b =3/4 in. [20 mm] for spans < 100 ft [30 m]See Table 5.6 for tabulated values.5.23.4Beam and Girder Camber (without Designed Concrete Haunch). For members whose top flange is embedded in concrete without adesigned concrete haunch, the maximum variation from required camber at shop assembly (for drilling holes for field splices or preparing field welded splices) shall beat midspan,± 3/4 in. [20 mm] for spans ≥ 100 ft[30 m]± 3/8 in. [10 mm] for spans < 100 ft [30 m]at supports,0 for end supports± 1/8 in. [3 mm] for interior supports at intermediate points, ± where a and S are as defined aboveb =3/4 in. [20 mm] for spans ≥ 100 ft [30 m]b =3/8 in. [10 mm] for spans < 100 ft [30 m]See Table 5.7 for tabulated values.Regardless of how the camber is shown on the detail drawings, the sign convention for the allowable vari-ation is plus (+) above, and minus (–) below, the 4(a)b(1 – a/S)S --------------------------------4(a)b(1 – a/S)S--------------------------------20/pgs. 188–189Copyright American Welding SocietyProvided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---21Table 5.6Camber Tolerance for Typical Girder (see 5.23.3 [pg. 188–189])Camber Tolerance (in inches)a/SSpan 0.10.20.30.40.5≥ 100 ft 9/1611-1/41-7/161-1/2< 100 ft1/41/25/83/43/4Camber Tolerance (in millimeters)a/SSpan 0.10.20.30.40.5≥ 30m 1425343840< 30 m713171920Table 5.7Camber Tolerance for Girderswithout a Designed Concrete Haunch(see 5.23.4 [pg. 188–189])Camber Tolerance (in inches)a/SSpan 0.10.20.30.40.5≥ 100 ft 1/41/25/83/43/4< 100 ft1/81/45/163/83/8Camber Tolerance (in millimeters)a/SSpan 0.10.20.30.40.5≥ 30 m713171920< 30 m468101021/pg. 194Copyright American Welding Society Provided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112, 08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---22detailed camber shape. These provisions also apply to an individual member when no field splices or shop assembly is required. Camber measurements shall be made in the no-load condition.5.23.5Beam and Girder Sweep. The maximum variation in specified sweep at the midpoint shall be1 mm × No. of meters of total lengthprovided the member has sufficient lateral flexibility to permit the attachment of diaphragms, cross-frames, lateral bracing, etc., without damaging the structural member or its attachments.5.23.6Variation in Web Flatness5.23.6.1Measurements. Variations from flatness of girder webs shall be determined by measuring the offset from the actual web centerline to a straight edge whose length is greater than the least panel dimension and placed on a plane parallel to the nomi-nal web plane. Measurements shall be taken prior to erection (see Commentary).5.23.6.2Statically Loaded Nontubular Struc-tures. Variations from flatness of webs having a depth, D, and a thickness, t, in panels bounded by stiffeners or flanges, or both, whose least panel dimension is d shall not exceed the following:Intermediate stiffeners on both sides of webwhere D/t < 150, maximum variation = d/100where D/t ≥ 150, maximum variation = d/80Intermediate stiffeners on one side only of web where D/t < 100, maximum variation = d/100where D/t ≥ 100, maximum variation = d/67No intermediate stiffenerswhere D/t ≥ 100, maximum variation = D/150(See Annex VI for tabulation.)5.23.6.3 Cyclically Loaded Nontubular Struc-tures. Variation from flatness of webs having a depth, D, and a thickness, t, in panels bounded by stiffeners or flanges, or both, whose least panel dimension is d shall not exceed the following: 1/8 in.No. of feet of total length10------------------------------------------------------------×±22/pg. 189Copyright American Welding SocietyProvided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please call the Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---23Intermediate stiffeners on both sides of web Interior girders—where D/t < 150—maximum variation = d/115where D/t ≥ 150—maximum variation = d/92Fascia girders—where D/t < 150—maximum variation = d/130where D/t ≥ 150—maximum variation = d/105Intermediate stiffeners on one side only of web Interior girders—where D/t < 100—maximum variation = d/100where D/t ≥ 100—maximum variation = d/67Fascia girders—where D/t < 100—maximum variation = d/120where D/t ≥ 100—maximum variation = d/80No intermediate stiffeners—maximum variation = D/150(See Annex VII for tabulation.)5.23.6.4 Excessive Distortion. Web distortions of twice the allowable tolerances of 5.23.6.2 or 5.23.6.3shall be satisfactory when occurring at the end of a girder which has been drilled, or subpunched and reamed; either during assembly or to a template for afield bolted splice; provided, when the splice plates are bolted, the web assumes the proper dimensional tolerances.5.23.6.5Architectural Consideration. If archi-tectural considerations require tolerances more restrictive than described in 5.23.6.2 or 5.23.6.3, spe-cific reference must be included in the bid documents.5.23.7 Variation Between Web and Flange Center-lines. For built-up H or I members, the maximum variation between the centerline of the web and the centerline of the flange at contact surface is 1/4 in.[6mm].5.23.8Flange Warpage and Tilt. For welded beams or girders, the combined warpage and tilt of flange shall be determined by measuring the offset at the toe of the flange from a line normal to the plane of the web through the intersection of the centerline of the web with the outside surface of the flange plate. This offset shall not exceed 1% of the total flange width or 1/4 in. [6 mm], whichever is greater, except that 23/pg. 189Copyright American Welding SocietyProvided by IHS under license with AWSDocument provided by IHS Licensee=Shell Services International B.V./5924979112,08/26/2004 23:33:59 MDT Questions or comments about this message: please callthe Document Policy Group at 303-397-2295.--`````,`,,``,`,,```,,,`,``-`-`,,`,,`,`,,`---。
焊接手册
焊接工艺手册第一节焊接的原理一、焊接原理:1．焊锡目的（1）电的接续（使金属与金属相接合，从而形成良好的电的导通）（2）机器的接续（使金属与金属相接合，从而固定两者之间的位置，实现持久的机械连接。
）（3）密闭的效果（通过焊锡可防止没有焊锡的部位进入空气、油、水等杂质）（4）其它（根据金属表面的镀金，可防止氧化处理）2．焊接的原理焊锡借助于助焊剂的作用，经过加热熔化成液态，进入被焊金属的缝隙，在焊接物的表面，形成金属合金使两种金属体牢固地连接在一起，不过焊接并不是通过熔化的焊料将元气件的引脚与焊盘进行简单的粘合，而是焊料中的锡与铜发生了化学反应，形成的金属合金就是焊锡中锡铅的原子进入被焊金属的晶格中生成的一种新的物质，因锡铅两种金属原子的壳层相互扩散，依靠原子间的内聚力使两种金属永久地牢固结合在一起。
如下图是放大1000倍的焊点剖面，这使我们清楚的看到在焊盘与焊料之间确实形成了新的物质，经过研究证明这种新物质是由Cu3Sn和Cu5Sn6。
3.焊接的分类不加热超声波焊接加压焊（加热或不加热）加热到局部熔化接触焊对焊金属焊接手工烙铁焊（锡线）浸焊（锡条）锡焊（母材不熔化、焊料熔化）焊锡波峰焊（锡条）再流焊（锡膏）4.有关焊锡之名词（1）点焊:将导线或元件脚穿过线路板或其它焊锡孔位,单个焊接在铜片位上,一次只焊接一个焊点.（2）贴焊:将零件脚、导线或排梳、排线等表面焊接在线路板其它锡点面上，一次只焊接一个焊点。
（3）拖焊：将排梳或排线穿过线路板锁孔，沿排孔方向进行焊接，一次可焊接多个焊点。
（4）执锡：过锡炉后的机芯板，有少锡、短路等不户锡点，需将其修改成完好锡点，即机芯执锡。
5.焊接必须具备的条件(1)、焊件必须具有良好的可焊性（在焊接时，由于高温使金属表面产生氧化膜，影响材料的可焊性，为了提高可焊性，一般采用表面镀锡、镀铜等措施来防止表面的氧化）(2)、焊件表面必须保持清洁（即使可焊性良好的焊件，由于储存或被污染，都可能在焊件表面产生有害的氧化膜和油污）(3)、要使用合适的助焊剂（不同的焊接工艺，应选择不同的助焊剂）(4)、焊件要加热到适当的温度（不但焊锡要加热到熔化，而且应该同时将焊件加热到能够熔化焊锡的温度）二．焊接的主要方法1. 焊接顺序（1）．将烙铁头在含水分的海绵上清理干净，准备焊接：左手拿锡丝，右手握烙铁，进入备焊状态。
法国GTT公司焊接手册
法国GTT公司焊接手册材料：殷瓦钢，材料厚度：0.7mm、1.0mm、1.5mm三个规格。
焊接形式：搭接、顶焊两种形式。
焊接位置：平焊、立焊、横焊和仰焊四种。
焊前准备：1.热保护绝缘衬垫；2.保护气体（纯度99.999%的氩气）；3焊接设备（钨极氩弧焊机）；4.劳保用品（弧焊面罩、胶皮手套、口罩等）；5.衬垫。
焊前清理：焊前应用浓度高于99.7%的无水酒精擦拭，去除表面的水分、灰尘和油污；用锉刀打磨掉钢板边缘的毛刺，打磨时自上而下轻轻打磨，不要用力快速来回打磨，打磨后立即清洗，要保证工作车间的空气干燥度≥60%，应配备除湿空调和湿度温度计，保证焊接车间的密封性。
人员要求：焊接人员必须经过专业的培训并取得焊工最高的等级证G级证，焊接人员焊接是应该佩戴胶皮手套和口罩以及相应的防护措施。
装配定位：确保装配是没有损伤，充分利用工装夹具，减小装配间隙，尽量做到无间隙，定位焊点的大小在保证两块板都焊到的情况下越小越好，避免熔到殷瓦钢板的上边缘，定位焊点间距为10mm一点。
定位时起弧收弧要求时间尽可能短，只要点一下起弧后就可以立马熄弧，定位焊的电流一般为焊接电流的2倍左右，具体根据板厚来定，一般常用的为45-65A。
焊接要点：焊接时，钨极尽量靠近两块殷瓦钢搭接板上边缘角，但是不能碰到，焊接过程为自右向左的Z型往返焊接，焊枪摆动频次为大约2s 摆动3次，中间不停顿。
立焊立焊位置焊接可进行自下往上或者自上往下的焊接，严格控制装配间隙，薄板处摆动需要越快越好。
仰焊仰焊焊接时焊接电流需适当减小。
顶焊焊接时，钨极与焊缝垂直，当两张板顶焊时，焊接方式采用钨极沿焊缝方向前后摆动；当三张板焊顶焊时，钨极沿垂直焊缝方向左右Z型摆动，把弄证熔池完全覆盖顶端。
焊接手册
焊接手册(第2版) 焊接方法及设备(第一卷)本卷共分6篇、41章，特点是焊接工艺与设备兼顾，原理与工艺（或设备）密切联系。
目的是引导读者正确选择和使用焊接方法及设备，并提供解决焊接工艺问题的基本途径。
具体内容包括各种电弧焊、电阻焊、高能束焊、钎焊、焊接过程自动化技术以及其他焊接方法等。
增加了药芯汉斯电弧焊及SMT中的焊接技术两章。
【目录】第1章焊接方法概述第1篇电弧焊第2章弧焊电源第3章焊条电弧焊第4章埋弧焊第5章钨极气体保护焊第6章等离子弧焊及切割第7章熔化极气体保护焊第8章药芯焊丝电弧焊第9章水下电弧焊于切割第10章螺柱焊第11章碳弧气刨第2篇电阻焊第12章点焊第13章缝焊第14章凸焊第15章对焊第16章电阻焊设备第17章电阻焊质量检验及监控第3篇高能束焊第18章电子束焊第19章激光焊于切割第4篇钎焊第20章钎焊方法及工艺第21章钎焊材料第22章各种材料的钎焊第5篇其他焊接方法第23章电渣焊及电渣压力焊第24章高频焊第25章气焊气割及高压水射流切割第26章气压焊第27章热剂焊(铝热焊)第28章爆炸焊第29章摩擦焊第30章变性焊第31章超声波焊接第32章扩散焊第33章堆焊第34章热喷涂第35章SMT中的焊接技术第36章胶接第6篇焊接过程自动化技术第37章焊接电弧控制技术第38章焊接传感器及伺服装置第39章计算机在焊接中的应用第40章焊接机器人第41章专用焊接设备设计概要-------------------焊接手册(第2版) 材料的焊接(第二卷)本卷分5篇、23章。
内容包括：材料焊接性基础、铁与钢、有色金属、异种材料、新型材料的焊接。
按生产的需要提供母材性能及焊接特点、焊接材料、焊接工艺、缺欠及防止，特别强调给出并分析生产实例、使手册更为实用。
【目录】第1篇材料的焊接性基础第1章焊接热过程第2章焊接冶金第3章焊接热影响区组织转变及其性能变化第4章焊接缺欠第5章金属焊接性及其试验方法第2篇铁与钢的焊接第6章碳钢的焊接第7章低合金钢的焊接第8章耐热钢的焊接第9章不锈钢的焊接第10章其它高合金钢的焊接第11章铸铁的焊接第3篇有色金属的焊接第12章铝、镁及其合金的焊接第13章钛及其合金的焊接第14章铜及铜合金的焊接第15章高温合金的焊接第16章镍基耐蚀合金的焊接第17章难熔金属的焊接第18章稀贵及其它有色金属的焊接第4篇异种材料的焊接第19章异种金属的焊接第20章金属材料堆焊第5篇新型材料的焊接第21章塑料的焊接第22章陶瓷与陶瓷陶瓷与金属的连接第23章复合材料的焊接--------------------焊接手册(第2版) 焊接结构(第三卷)本卷分为3篇、27章，介绍了焊接结构选材、设计、制造诸方面的问题，力求通过对典型结构的分析等介绍合理的焊接。
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1焊接概述1.1 焊接的定义被焊工件的材质（同种或异种），通过加热或加压或两者并用，并且用或不用填充材料，使工件的材质达到原子（分子）间的结合而形成永久性连接的工艺过程称为焊接（Welding）。
随着现代工业生产的需要和科学技术的蓬勃发展，焊接技术进步很快，到现在焊接方法已发展到数十种之多。
为了能正确选择和使用各种焊接方法，必须了解焊接的物理本质、它们的分类、基本特点和使用范围。
1.2 焊接过程的物理本质焊接促使原子或分子之间产生结合和扩散的方法是加热或加压，或者两者并用。
两材料原子之间不能产生结合和扩散的主要原因是材料的连接表面有氧化膜、水、和油等吸附层以及两材料原子之间尚未达到产生结合力的距离，对金属而言该距离约为3～5À（1À=10-7mm）。
焊接时，加压可以破坏连接表面的氧化膜，产生塑性变形以增加接触面，使原子间达到产生结合力和扩散的条件；加热的目的是使接触面的氧化膜破坏，降低塑性变形阻力，增加原子振动能，促进再结晶、扩散、化学反应等过程。
一般只需要加热达塑性状态或熔化状态。
对金属材料，加热温度越高，实现焊接所需的压力越小，当达到熔化温度时，可以不需要加压。
1.3 焊接方法的分类金属的焊接，按其工艺过程的特点分有熔焊、压焊和钎焊三大类，见表1—3—1。
熔焊在连接部位需加热至熔化状态，一般不加压；压焊必须施加压力，加热是为了加速实现焊接；钎焊时母材不熔化，只熔化起连接作用的填充材料（钎料）。
1.4 常用焊接方法基本特点与应用表1-4-1简要地介绍了本单位常用金属焊接方法的原理、特点及使用范围。
1.5 焊缝符号1.5.1 基本符号焊缝的基本符号见表1-5-1表1—3—1 焊接方法分类（注：常见的栓钉焊属于熔焊加压焊。
）表1-4-1 常用焊接方法基本特点与应用表1-4-1续等离子弧焊利用气体(多为Ar)和特殊装置压缩电弧获得高能量密度的等离子弧进行焊接,电极有钨极和熔化极两种具有Ar弧焊的一些特点,但等离子弧温度很高,穿透能力强,可正面一次焊透双面成形.电弧挺度好可压缩成束状焊微型件一次焊透厚度在0.025～6.4mm,低碳钢8mm以内,也适用于焊接微小精密构件气体保护CO2气体保护焊用二氧化碳保护,用焊丝做电极的弧焊热量较集中,热影响区小,变形小,成本低,生产率高,易于操作.飞溅较大,焊缝成形不够美观,余高大,设备较复杂,须避风适用于1.6mm以上由低碳钢、低合金钢制造的各种金属结构等离子弧焊利用气体(多为Ar)和特殊装置压缩电弧获得高能量密度的等离子弧进行焊接,电极有钨极和熔化极两种具有Ar弧焊的一些特点,但等离子弧温度很高,穿透能力强,可正面一次焊透双面成形.电弧挺度好可压缩成束状焊微型件一次焊透厚度在0.025～6.4mm,低碳钢8mm以内,也适用于焊接微小精密构件电渣焊利用电流通过熔渣产生的电阻热熔化金属进行焊接,可熔化的金属电极有丝状和板状两种直缝须立焊,任何厚度不开坡口一次焊成,生产率高,但热影响区宽、晶粒粗大,易生成过热组织,焊后须正火处理改善接头组织和性能适用于厚度25mm以上的重大型机件的焊接,直焊碳素钢、合金钢熔化加压焊栓钉焊(也叫螺柱焊)引弧与焊条电弧焊相似,先将栓钉的尖端与钢结构接触,通过强大焊接电流,短路,瞬间达到高温,焊枪中磁力提升栓钉、引弧、产生熔池;之后,立即释放磁力,利用弹簧使栓钉压入熔池,断电后冷却形成接头.栓钉提升高度在焊枪中提前调定加热过程是稳定的电弧燃烧过程,为了防止空气侵入溶池,恶化接头质量,要采用陶瓷环保护.焊接质量可靠,效率高,无烟雾弧光,劳动条件好在钢-混凝土结构,为了提高钢构件与混凝土间的结合力,多采用此焊接方法.也可焊接固定小器具的受柄、支脚用螺柱等.可焊材料有碳钢、高碳钢、低合金高强度钢、不锈钢和铝合金表1-5-1 焊缝的基本符号序号名称示意图符号1卷边焊缝①(卷边完全熔化)2 I 形焊缝3 V 形焊缝4 单边V形焊缝5 带钝边V形焊缝带钝边单边V形6焊缝7 带钝边U形焊缝8 带钝边J形焊缝9 封底焊缝10 角焊缝11 塞焊缝或槽焊缝12 点焊缝13 缝焊缝①不完全熔化的焊缝用I形焊缝表示，并加注焊缝有效厚度。
焊缝的辅助符号是表示焊缝表面形状特征的符号，见表1-5-2。
表1-5-2 焊缝的辅助符号序号名称示意图符号说明1 平面符号焊缝表面齐平(一般通过加工)2 凹面符号焊缝表面凹陷3 凸面符号焊缝表面凸起不需要确切地说明焊缝的表面形状时，可以不用辅助符号。
焊缝的辅助符号的应用见表1-5-3。
表1-5-3 焊缝的辅助符号的应用名称示意图符号平面V形对接焊缝凸面X形对接焊缝凹面角焊缝平面封底V形焊缝焊缝的补充符号是为了补充说明焊缝的某些特征而采用的符号，见表1-5-4。
1.5.4焊缝尺寸符号基本符号必要时可附带有尺寸符号及数据，这些尺寸符号见表1-5-5。
1.5.5指引线及说明（见表1-5-6）1.5.6焊缝符号标注的原则和方法（见表1-5-7）1.5.7常见金属焊接方法代号（见表1-5-8）1.5.8 焊缝符号标注示例（见表1-5-9）表1-5-4焊缝的补充符号序号名称示意图符号说明1 带垫板符号①表示焊缝底部有垫板2 三面焊缝符号①表示三面有焊缝3 周围焊缝符号表示环绕工件周围焊缝4 现场符号表示在现场或工地上进行焊接5 尾部符号可以参照GB5185标注焊接工艺方法等内容①ISO2553标准中未做规定。
表1-5-5 焊缝尺寸符号①符号名称示意图符号名称示意图δ工件厚度 e 焊缝间距α坡口角度K 焊角尺寸b 根部间隙 d 熔核直径焊缝有效厚p 钝边S度相同焊缝数c 焊缝宽度N量R 根部半径H 坡口深度l 焊缝长度h 余高n 焊缝段数β坡口面角度①对焊缝尺寸符号，ISO2553标准未做规定表1-5-6指引线及说明基准线有一条实线和一条虚线,均应与图样底边平行,特殊情况允许与底边垂直.虚线可画在实线上侧或下侧.如焊缝在接头的箭头侧,则将基本符号标在实线侧;反之标在虚线侧;对称、双面焊缝时可不加虚线.箭头线一般没有特殊要求;但是在标注单边V形、带钝边单边V形和带钝边J形焊缝时,箭头线应指向带坡口一侧的工件;必要时,允许箭头线弯折一次.尾部一般剩去,只有对焊缝有附加要求或说明时才加上尾部部分.表1-5-7焊缝符号标注的原则和方法基本符号焊缝在接头的箭头侧,则将基本符号标在实线侧;反之标在虚线侧;对称、双面焊缝时可不加虚线.基本符号标在基准线两侧焊缝形状尺寸焊缝截面尺寸标在基本符号左侧;焊缝长度尺寸标在基本符号右侧;坡口角度,根部间隙等标在基本符号的上侧或下侧.其他相同焊缝符号、焊接方法代号、检验方式符号、其他要求和说明等标在尾部右侧表1-5-8常见金属焊接方法代号①① 摘自GB/T5185-85金属焊接及钎焊方法在图样上的表示代号 表1-5-9焊缝符号标注示例2焊接设计2.1 材料选用2.1.1 母材材料选用2.1.1.1 钢结构对材料的要求钢结构所用的钢必须符合下列要求： 1） 较高的抗拉强度f u 和屈服点f yfy 是衡量结构承载能力的指标，fy高则可减轻结构自重、节约钢材和降低造价。
fu是衡量钢材经过较大变形后的抗拉能力，它直接反映钢材内部组织的优劣，同时fu高可以增加结构的安全保障。
2）较高的塑性和韧性塑性和韧性好，结构在静载和动载作用下有足够的应变能力，既可减轻结构脆性破坏的倾向，又能通过较大的塑性变形调整局部应力，同时又具有较好的抵抗交变荷载作用的能力。
3）良好的工艺性能良好的工艺性能不但能保证通过冷加工、热加工和焊接加工成各种形式结构，而且不致因加工而对结构的强度、塑性、韧性等造成较大的不良影响。
此外，根据结构的具体工作条件，有时还要求钢材具有适应低温、高温和腐蚀性环境能力。
按以上要求，钢结构设计规范具体规定：承重结构的钢材应具有抗拉强度、伸长率、屈服点和碳、硫、磷含量的合格保证；焊接结构尚应具有冷弯试验的合格保证；对某些承受动力荷载的结构以及重要的受拉或受弯的焊接结构尚应具有常温或负温冲击韧性的合格保证。
2.1.1.2 钢结构用钢的分类在钢结构中采用的钢材主要有两种：碳素结构钢（或称普通碳素钢）和低合金结构钢。
1）碳素结构钢根据国家标准《碳素结构钢》（GB700-88）的规定，将碳素结构钢分为Q195、Q215、Q235、Q255和Q275等五种牌号，钢的牌号有屈服强度字母（Q）、屈服强度值、质量等级符号（A、B、C和D）、脱氧方法符号等四部分顺序组成。
常见用钢具体参数见表2-1-1。
2）低合金钢根据《低合金高强度结构钢》（GB1591-94）的规定，低合金高强度结构钢分为Q295、Q345、Q390、Q420和Q460等五种，其中Q345、Q390为钢结构常用钢种，Q420已在九江长江大桥中成功使用。
具体参数见表2-1-1。
2.1.1.2 钢结构用钢选用原则钢材的选用在钢结构设计中是重要的一环，选择的目的是既要保证结构的安全，又要做到可靠和经济合理。
选择钢材时应考虑以下几点。
1）结构的重要性对重型工业建筑钢结构、大跨度钢结构、压力容器、高层或超高层民用建筑或构筑物等重要结构，应考虑选用质量好的钢材；其他按工作性质分别选用普通质量的钢材；另外，安全等级不同，要求的钢材质量也应不同。
2）载荷情况一般承受静载荷的结构，应主要以满足强度要求来选取。
直接承受交变载荷的结构，若属于低周疲劳，在保证一定强度要求下，着重考虑材料的塑性和韧性；若属于高周疲劳，这时强度队疲劳抗力起着主导作用，应选择强度高的材料。
承受冲击载荷的结构，所选材料应具有足够的延性和韧性。
按刚度条件设计的结构，其工作应力一般比较小，但其壁厚较厚，此时选材不应是高强度的，而应是塑性和韧性好的一般强度的材料。
在厚度方向受到拉伸载荷，应选择层状夹杂少，厚度方向塑性好的材料，以防止产生层状撕裂。
3）连接方法焊接结构对材质的要求应严格一些。
例如，在化学成分方面必须严格控制碳、硫、磷的含量；非焊接结构对碳当量可放宽要求。
4）结构所处的温度和环境在低温条件下工作的结构，尤其是焊接结构，应选用具有良好抗低温脆断性能的镇静钢。
露天结构易产生时效，有害介质作用的钢材易腐蚀、疲劳和断裂，应区别地选择不同的材质，宜采用耐候钢，其质量要求应符合现行国家标准GB/T4172《焊接结构有耐候钢》的规定。
5）钢材厚度厚钢材辊轧次数少，轧制压缩比相对薄板小。
所以厚度大的钢材不仅强度较小，而且塑性、冲击韧性和焊接性能也较差。
因此，厚度大的焊接结构应采用材质好的钢材。
推荐采用Z向钢，其材质应符合现行国家标准GB/T5313《厚度方向性能钢材》的规定。
6）对于需要演算疲劳的焊接结构的钢材，应具用常温冲击韧性的合格保证。
当结构工作温度不高于0℃但高于-20℃时，Q235钢和Q345钢应具用0℃冲击韧性的合格保证；对Q390钢和Q420钢应具有-20℃冲击韧性的合格保证。