US 5,389,761 AGranted

Method and apparatus for cleaning metal pieces prior to resistive seam welding or laser lap seam welding

AssigneeGeneral Motors Corporation

InventorAlfred L. Kresse, Jr.

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Abstract

An apparatus comprises a current source, first and second wheels through which a current from the current source selectively flows, and a source of gas, wherein the first and second wheels receive first and second pieces of metal having overlapping portions, force the first and second pieces of metal together at said overlapping portions. The current from the current source flows through the first and second wheels in the overlapping portions of the first and second pieces of metal, generating heat in said first and second pieces of metal sufficient to melt a coating on the first and second sheets of metal where the first and second sheets of metal contact and overlap. The source of gas comprises removes said melted coatings away from the overlapping portions of metal to clean the metal surfaces in preparation for movement to a weld station where the pieces of metal are resistive seam welded or laser lap seam welded. Preferably the source of gas supplies an inert gas to prevent reoxidation of the pieces between the apparatus and the weld station.

Claims14

Dependent claims

A method comprising the steps of:

placing first and second pieces of metal so that each of the pieces of metal overlaps at least a portion of the other piece of metal and comprises a contacting surface in physical contact with the other piece of metal at the overlapping portion, wherein at least one of the first and second pieces of metal comprises an additional material on the contacting surface;
rolling the overlapping portions of the first and second pieces of metal through a pair of rollers;
providing current through the rollers and the overlapping portions as the overlapping portions are rolled through the pair of rollers, wherein the current heats the metal and additional material and creates a fluid melt zone between the overlapping portions:
flowing a stream of inert gas at said fluid melt zone to remove from between the overlapping portions at least a portion of the fluid melt zone and at least a portion of the additional material as the overlapping portions exit the rollers;
and thereafter
moving the overlapping portions to a weld station to seam weld the first and second pieces of metal at said overlapping portions, whereby oxidations and coatings have minimal affect on weld results, wherein a residue of the flowing inert gas bathes an area between the rollers and the weld station to impede oxidation of the overlapping portions from which the fluid melt zone and additional material were removed and wherein continuous cleaning and seam welding of the first and second pieces of metal are accomplished.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/122,086Filed 17 Sep 1993
Granted: 14 Feb 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

B23K 11/34
Resistance welding; Severing by resistance heating: preliminary treatment
B23K 11/163
Taking account of the properties of the material to be welded: welding of coated materials
B23K 26/142
Using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor: for the removal of by-products
B23K 26/147
Supply to, or discharge from, nozzles of media, e.g. gas, powder, wire: features outside the nozzle for feeding the fluid stream towards the workpiece