Method of joining galvanized steel parts using lasers
AssigneeGeneral Motors Corporation
InventorsPei-Chung Wang, Wenkao Hou
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Abstract
This invention provides a method of joining overlapping galvanized steel parts using two lasers for in tandem slot cutting and welding. A first laser beam impacts the steel parts at an energy level sufficient to cut a slot at least through the facing steel part to provide a path for vaporized zinc to escape from a welding interface. Immediately after the first laser beam passes, a second laser beam is directed along the slot at an energy level sufficient to melt ferrous material to fill the slot. After the second laser beams passes, the molten metal is cooled by the surrounding unheated metal to solidify and form a weld nugget.
Claims12
A method of welding a steel sheet metal part having a zinc galvanized coating to a second sheet metal part where said parts are held together in overlapping configuration and zinc coating material is present at a welding interface of said overlapping parts, said method comprising:
- directing a first laser beam on a surface of said steel part and advancing said first laser along said surface to cut a slot through said steel part, at least to the depth of said steel part's interface with said second part, in a path for a welding seam, the energy of said first laser and the depth and width of said slot being sufficient to evaporate zinc from said interface through said slot;
- directing a second laser beam along said slot following said first laser beam, said second laser beam having sufficient energy to melt ferrous metal into said slot for said weld;
- and
- cooling the molten metal to complete said weld.
Dependencies are inferred from the claim text.