Resistance welding of high strength steels
AssigneeGeneral Motors Corporation
InventorPei-Chung Wang
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Abstract
The formation of spot welds in high strength steel workpieces is improved by using welding electrodes with annular, or donut shaped welding tips for the formation of the molten metal weld pool at the weld site. The annular poll solidifies to form an annular weld nugget. Preferably the donut shaped nugget has an internal diameter that is no more than three-quarters of the outside diameter. The method is applicable to carbon steel workpieces with allowing elements for strengthening, and to thick sheets of mild carbon steels.
Claims6
A method of forming a welded bond at a weld site that includes an interface between first and second high strength steel workpieces, the high strength steel containing, by weight, at the weld site, 0.06–0.25% carbon, 0.4–1.7% manganese and one or more of the elements selected from the group consisting of aluminum, chromium, molybdenum, niobium, nickel, phosphorus, sulfur, silicon, titanium and vanadium, the method comprising:
- passing an electrical current through said workpieces at said weld site to form an annular pool of molten steel material at said interface;
- and, thereafter
- stopping said electrical current for solidification of said molten material into an annular weld nugget bonding said workpieces at said interface said annular weld nugget having a central opening with no weld nugget material therein.
Dependencies are inferred from the claim text.