Method and apparatus for flash welding

摘要

A method and apparatus for flash welding are disclosed wherein a first predetermined voltage is applied between a pair of workpieces to be welded to generate flashes therebetween, and a second predetermined voltage lower than the first predetermined voltage is then applied between the workpieces to maintain fine flashes when the temperature of weld surfaces of the workpieces has reached a predetermined temperature. The workpieces are upset when the total number of flashes has reached a predetermined value. The pressure welding is maintained with an upsetting pressure sufficient to upset the workpieces and slightly higher than a pressure at which the workpieces are deformed near their recrystallization temperature until the temperature of weld surfaces has decreased to lower than the recrystallization temperature. The applied voltage and the upsetting pressure are controlled in accordance with the weld progress.