BS 1140:1993

Specifies procedures in the fabrication of assemblies of uncoated and coated low carbon steel comprising two or three thicknesses of metal where the single sheet thickness is within certain given limits.

This British Standard specifies 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:

1. uncoated sheets: 0.4 mm to 3.0 mm (see 5.1);
2. uncoated plates: 3.0 mm to 12.0 mm (see 5.1);
3. hot-dip zinc coated sheets: 0.4 mm to 3.0 mm (see 5.2);
4. hot-dip iron-zinc alloy coated sheets (galvaneal): 0.4 mm to 3.0 mm (see 5.2);
5. electrolytic zinc coated sheets: 0.4 mm to 3.0 mm (see 5.3);
6. electrolytic zinc-nickel coated sheets: 0.4 mm to 3.0 mm (see 5.4);
7. terne coated sheets: 0.4 mm to 3.0 mm (see 5.5);
8. aluminium coated sheets: 0.4 mm to 3.0 mm (see 5.6);
9. hot-dip zinc-55 % aluminium coated sheets 0.4 mm to 3.0 mm (see 5.7);
10. hot-dip zinc-5 % aluminium coated sheets 0.4 mm to 3.0 mm (see 5.8).

Guidance on the choice of appropriate welding equipment 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 requires the items detailed in clause 4 to be documented. For compliance with this standard, both the definitive requirements and the documented items have to be satisfied.