1、BRITISH STANDARD BS 1140:1993 Specification for Resistance spot welding of uncoated and coated low carbon steel UDC 669.141.24:621.791.763.1BS1140:1993 This British Standard, having been prepared under the direction of the Welding Standards Policy Committee, was published under the authority of the
2、Standards Board and comes into effect on 15 May 1993 BSI 12-1998 First published October 1943 Second edition October 1946 Third edition November 1957 Fourth edition June 1980 Fifth edition May 1993 The following BSI references relate to the work on this standard: Committee reference WEE/29 Draft for
3、 comment 90/71477 DC ISBN 0 580 21944 5 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Welding Standards Policy Committee (WEE/-) to Technical Committee WEE/29, upon which the following bodies were represented: British Steel Industry Ra
4、ilway Industry Association of Great Britain Society of Motor Manufacturers and Traders Ltd. Welding Institute Welding Manufacturers Association (BEAMA Ltd.) Coopted members Amendments issued since publication Amd. No. Date CommentsBS1140:1993 BSI 12-1998 i Contents Page Committees responsible Inside
5、 front cover Foreword iii 1 Scope 1 2 References 1 3 Definitions 1 4 Items to be agreed between the contracting parties 3 5 Parent metal 3 5.1 Uncoated steel 3 5.2 Hot-dip zinc and iron-zinc coated steel 3 5.3 Electrolytic zinc coated steel 3 5.4 Electrolytic zinc-nickel coated 3 5.5 Terne coated st
6、eel (nominal Pb/10 % Sn coating) 3 5.6 Aluminium coated steel 3 5.7 Zinc-55 % aluminium coated steel 3 5.8 Zinc-5 % aluminium coated steel 3 6 Surface conditions 4 7 Edge conditions, form of component and weld pitch 4 8 Electrodes 5 8.1 Materials 5 8.2 Dimensions 5 8.3 Cooling 5 9 Weld assessment Ge
7、neral 5 9.1 Procedure 5 9.2 Type tests 6 9.3 Routine tests 7 10 Weld assessment Tests 7 10.1 General 7 10.2 Shear test 7 10.3 Cross-tension test (optional) 7 10.4 Peel test or chisel test 9 10.5 Visual examination 9 10.6 Metallurgical examination 10 10.7 Hardness test (optional) 10 11 Weld assessmen
8、t Acceptance criteria 10 11.1 General 10 11.2 Weld dimensions 10 11.3 Weld appearance 10 11.4 Weld diameter 10 11.5 Weld fracture mode 10 11.6 Distortion 10 12 Routine inspection of welded components 10 13 Facilities for inspection 11 14 Testing facilities 11 Annex A (informative) Recommendations fo
9、r spot welding equipment 12 Annex B (informative) Typical spot welding conditions 12 Annex C (normative) Typical information to appear on a welding procedure sheet for spot welding 15 Annex D (informative) Calculation of weld strength 16BS1140:1993 ii BSI 12-1998 Page Figure 1 Measurement of weld si
10、ze 2 Figure 2 Minimum pitch for welds in uncoated low carbon steel sheet thickness 0.4 mm to 12 mm 4 Figure 3 Schematic weldability lobe 6 Figure 4 Shear test piece 8 Figure 5 Cross-tension test piece 8 Figure 6 Jigging arrangement for cross-tension test piece 9 Table 1 Dimensions of shear test piec
11、e 7 Table 2 Dimensions of cross-tension test piece 7 Table B.1 Typical spot welding conditions for uncoated low carbon steel sheet of thickness 0.4 mm to 3.0 mm 13 Table B.2 Typical spot welding conditions for uncoated low carbon steel plate of thickness 3.0 mm to 12.0 mm using a single-phase a.c. m
12、achine 13 Table B.3 Typical spot welding conditions for uncoated low carbon steel strips or plates of thickness 3.0 mm to 12.0 mm using a three-phase a.c. machine 13 Table B.4 Typical spot welding conditions for hot-dip zinc, zinc-5 % aluminium, zinc-55 % aluminium and electrolytically deposited zin
13、c coated steel sheets of combined thickness 0.4 mm to 3.0 mm 14 Table B.5 Typical spot welding of double sided iron-zinc alloy and zinc-nickel alloy coated steels of sheet thickness 0.4 mm to 3.0 mm 14 Table B.6 Typical spot welding conditions for two terne coated steel sheets of thickness 0.4 mm to
14、 1.6 mm 15 Table B.7 Typical spot welding conditions for aluminium coated steel sheet of thickness 0.4 mm to 2.0 mm 15 Table D.1 Typical minimum weld strength values (shear to failure) for low carbon steel of 280 N/mm 2minimum tensile strength 16 List of references Inside back coverBS1140:1993 BSI 1
15、2-1998 iii Foreword This revision of BS 1140 has been prepared under the direction of the Welding Standards Policy Committee. BS 1140 was first published in 1943, being subsequently revised in 1946, 1957 and 1980. It forms one of a series of standards on resistance processes. The applications of the
16、 spot welding process are so wide that it is not practicable to give specific welding conditions. However, a series of annexes gives information designed to assist the choice of welding conditions where these are not specified in a relevant application standard. A British Standard does not purport t
17、o include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover,
18、 pages i to iv, pages1to 16, aninside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.iv blankBS1140:1993 BSI 12-1998 1 1 Scope This British Standard spec
19、ifies procedures for resistance spot welding in the fabrication of assemblies of uncoated and coated low carbon steel comprising two or three thicknesses of metal, where the single sheet thickness of the components to be welded is within the following ranges: a) uncoated sheets: 0.4mm to 3.0mm (see5
20、.1); b) uncoated plates: 3.0mm to 12.0mm (see5.1); c) hot-dip zinc coated sheets: 0.4mm to 3.0mm (see5.2); d) hot-dip iron-zinc alloy coated sheets (galvaneal): 0.4mm to 3.0mm (see5.2); e) electrolytic zinc coated sheets: 0.4mm to3.0mm (see5.3); f) electrolytic zinc-nickel coated sheets: 0.4 mm to3.
21、0mm (see5.4); g) terne coated sheets: 0.4mm to 3.0mm (see5.5); h) aluminium coated sheets: 0.4mm to 3.0mm (see5.6); i) hot-dip zinc-55 % aluminium coated sheets0.4mm to 3.0mm (see5.7); j) hot-dip zinc-5 % aluminium coated sheets0.4mm to 3.0mm (see5.8). Guidance on the choice of appropriate welding e
22、quipment and approximate spot welding conditions is given in annexes A and B respectively. This procedure does not apply to the welding of sheets or plates of dissimilar thickness where the thickness ratio is greater than 3 to 1. In addition to the definitive requirements, this standard also require
23、s the items detailed in clause4 to be documented. For compliance with this standard, both the definitive requirements and the documented items have to be satisfied. 2 References 2.1 Normative references This British Standard incorporates, by reference, provisions from specific editions of other publ
24、ications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this British Standard only when incorporated in it by updating or revision. 2.2
25、 Informative references This British Standard refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Definitions For th
26、e purposes of this British Standard, the following definitions apply. For other technical terms applicable to this British Standard, the definitions given in BS499-1:1991 apply. 3.1 weld size the average weld diameter 3.2 weld nugget a zone in a resistance weld where the metal has been melted 3.3 no
27、minal weld diameter the diameter of the plug (slug) measured at the base of the nugget (seeFigure 1) 3.4 cross-tension test a test to determine the tensile force that the weld can sustain 3.5 shear test a test to determine the shear force that the weld can sustain 3.6 corona bond the area of the wel
28、d at the faying surfaces, in which solid phase bonding has occurred see Figure 1b) 3.7 interface failure the fracture through the weld between the sheets at the plane of the interface 3.8 plug (slug) failure the fracture of a weld through the sheet thickness at the edge of the weld see Figure 1a)BS1
29、140:1993 2 BSI 12-1998 Figure 1 Measurement of weld sizeBS1140:1993 BSI 12-1998 3 4 Items to be agreed between the contracting parties The following items to be agreed between the contracting parties, which are specified in the clauses referred to, shall be fully documented. Both the definitive requ
30、irements specified throughout the standard and the following documented items shall be satisfied before a claim of compliance with this standard can be made and verified: a) whether weld quality requirements are to be based on the application standard or annex B or are to be the subject of discussio
31、n and agreement (see clause11); b) whether edge distances less than the specified values are to be agreed (see note 2 to clause7); c) electrode dimensions where BS4215-2:1987 or BS EN21089:1992 do not apply or where the single material thickness is greater than 3 mm (see8.2.2); d) application of lar
32、ger or smaller electrode tip diameters (see notes 2, 3 and 4 to8.2.3); e) whether cross-tension and/or hardness tests are to be carried out, and whether dynamic tests are to be carried out (see9.2.2); f) type tests: dimensions of shear and cross-tension test pieces of a thickness other than that giv
33、en inTable 1 andTable 2 respectively (see10.2.1.2 and10.3.1.2 respectively); g) type tests and routine tests: method for hardness testing and hardness acceptance criteria (see10.7); h) type tests: whether interface failures are acceptable (see11.5). i) type tests: weld acceptance criteria where no a
34、ppropriate application standard exists (seeclause11); j) whether it is the intention of the purchaser to inspect production and testing (see clause13). 5 Parent metal 5.1 Uncoated steel Low carbon steel shall be flat rolled in coil or cut length form and shall be free from harmful imperfections. She
35、et and strip material shall conform to the general requirements and chemical composition specified in BS 1449-1:1991. Plate material shall conform to BS1449-1:1991 or BS4360:1990, as relevant. NOTEGrades 1 to 4 are readily weldable, but in certain applications modified procedures may be necessary, e
36、.g. when welding steels at the higher compositional limits. 5.2 Hot-dip zinc and iron-zinc coated steel Zinc coated steel, which is available in various base steel compositions, coating types and surface treatments, shall conform to the requirements for hot-dip zinc coated and iron-zinc coated steel
37、 coil and cut lengths, in forming and structural grades, coated by a continuous process, specified inBS2989:1992. Coating types and coating mass shall conform to BS2989:1992, the zinc alloy coatings (also known as galvaneal) and the lower mass zinc coatings being the most readily weldable. 5.3 Elect
38、rolytic zinc coated steel Electrolytic zinc coated steel shall be produced by electrolytic deposition of pure zinc on low carbon steel sheet and shall conform to BS6687:1986. The maximum coating thickness per side shall be 10 m (equal to a coating mass of 71 g/m 2for each surface). 5.4 Electrolytic
39、zinc-nickel coated steel Such coatings deposited electrolytically shall be limited to a maximum coating thickness per side of7m (equal to a coating mass of 50g/m 2for each surface). 5.5 Terne coated steel (nominally Pb/10% Sn coating) Terne coated steel shall conform to BS6582:1985. The maximum coat
40、ing mass shall have a nominal value of 150g/m 2 , including both surfaces. 5.6 Aluminium coated steel Aluminium coated steel shall be produced by the hot-dip process, the coating containing 5% to 11% silicon, and shall conform to the relevant requirements of BS6536:1985. NOTEA coating mass up to a n
41、ominal value of 150 g/m 2 , including both surfaces is considered to be the most readily weldable. 5.7 Zinc-55% aluminium coated steel Zinc-55% aluminium coated steel produced by the hot-dip process shall conform to BS6830:1987. The maximum coating mass shall be 185g/m 2 , including both surfaces, f
42、or the more readily weldable grades. 5.8 Zinc-5% aluminium coated steel Zinc-5% aluminium coated steel shall be produced by the hot-dip process. The maximum coating mass shall be 180g/m 2 , including both surfaces, for the more readily weldable grades.BS1140:1993 4 BSI 12-1998 6 Surface conditions P
43、rior to welding, all surfaces to be spot welded shall be free from paint, grease, scale, rust, print, dirt or excessive pitting. NOTECertain surface treatments such as the application of paint primers, rust prevention treatment, oils, lubricants or plating may be applied before welding, provided tha
44、t the coating is uniform in thickness and that it has been proved that consistent welds that conform to this standard can be obtained. In the case of paint primers etc., reference should be made to BS4129. Excessive use of surface pretreatment should be avoided if maximum electrode life is to be ach
45、ieved. Generally, heavy phosphate pretreatments of steel are not recommended prior to spot welding. 7 Edge conditions, form of component and weld pitch The components to be welded shall be free from burrs or other imperfections which would in any way interfere with interface contact or require exces
46、sive force to fit the parts together. The shape of the component shall be such that there is proper interface contact at the areas where the welds are to be made. NOTEThe recommended distance from the edge of the component to the centre of the weld should be not less than1.25d, where d is the recomm
47、ended weld diameter as defined by: d = 5 t where t is the sheet thickness (in mm). NOTE 2Where edge distances less than the recommended values are used, these should only be by agreement between the contracting parties. In this case the nominal weld size may be less than that given by the above equa
48、tion and therefore due allowance needs to be made for a lower weld strength. The minimum pitch of the welds, i.e. the centre-to-centre distance of the spots, shall be such as to maintain weld quality as assessed by the requirements given in clauses10 and11. NOTE 3Figure 2 shows the minimum pitch at
49、which welds can be obtained with no increase of weld energy after making the first weld on a component of uncoated steel, and without substantial reduction in size. For thinner sheets the minimum pitch approximates to 3d. Smaller pitches may be employed if the current is increased after the first weld. Figure 2 Minimum pitch for welds in uncoated low carbon steel sheet thickness0.4mmto12mmBS1140:1993 BSI 12-1998 5 8 Electrodes 8.1 Materials The welding electrodes shall be of copper alloy of sufficient cross-sectional area and
