JPS55112183A - Spot welding method of steel plate - Google Patents

Abstract

PURPOSE: To spot-weld steel plates without applying any pretreatment at all by holding the weld section of the superposed steel plates to be welded between the electrodes of a spot welding machine under pressure and applying ultrasonic vibrations thereto then supplying welding current between the both electrodes.

CONSTITUTION: The portion where exists the superposed faying point of the plate materials to be bonded is placed on a cradle or electrode and is held under required pressure between the both electrodes or between the electrode and cradle, after which ultrasonic vibrations are applied thereto. Thence, welding current is supplied between the both electrodes or between the electrode and cradle through the plate materials to be welded and the superposed plate materials are spot-welded. Here, the plate materials to be welded are rubbed with each other by the application of the foregoing ultrasonic vibrations and the film of precoating, etc. is melted by the friction heat and is expelled to outside the faying point. In the case of rusted plates, the ultrasonic vibrations remove rust and flatten the finely undulated surfaces having been produced on the surface through rust formation to crean metal surfaces, thus the rust and removed metal powder may be removed to outside the faying point.

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