Newcor, Inc.

Robert G Van Otteren

Charles H Gage

Alfred R Leger

Darin M Gilbert

Samuel E Lewis

Frank Scott Mellen

A process and apparatus for projection welding of overlapping nonferrous sheets, particularly thin aluminum sheets. One of the sheets is provided with a projection therein, and the sheets are positioned so that the tip of the projection contacts a surface of the other sheet. The sheets are not subjected to surface pretreatment to remove the surface oxides therefrom. A projection welding head assembly is positioned with the electrode thereof engaged with one of the sheets, and the other sheet is positioned against a stationary backup or electrode. The electrode of the welding head imposes, in rapid time succession, a series of welding pulses to the overlapping contacting sheets. The series of welding pulses includes two and preferably three pulses which progressively step up in amperage to provide for precise control of the heating of the projection and the associated contact area on the other sheet to cause heating to the plastic state, and then forging (i.e. collapsing) of the projection with subsequent and progressive creation of the desired weld nugget. The series of weld pulses also preferably includes, at the end of the series, one or two pulses which progressively step down in current magnitude to permit greater control over the plasticity of the projection and the forging together of the overlapping sheets to create the desired weld bead.

Method and apparatus of projection welding

A process and apparatus for effecting preheating of elongate metal parts, such as bars, for permitting subsequent deformative processing of the bar. Electrode-type clamps are attached adjacent opposite ends of the elongate bar, and direct-current electricity is applied to the clamps for transmission longitudinally of the bar to effect heating thereof. A further pair of electrode-type clamps is applied directly at each free end of the bar, with the electrode clamps of each end pair being disposed for engagement on opposite sides of the bar substantially flush with the end face of the bar. An electric current, such as an alternating-current, is applied across the sidewardly-spaced electrode clamps of each end pair to effect transmission of electrical current transversely across the bar in the direct vicinity of the end face to effect additional heating directly at the end of the bar to supplement the heating which is effected by the direct-current passed longitudinally through the bar.

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Bay City, MI, United States of America

Robert G Van Otteren