Method and device for welding protected metal parts

摘要

A method and apparatus for welding or brazing of sheetmetal or plate covered with a temperature degradable protective coat, such as zinc or plastic. A cooling saddle supplied with liquid nitrogen is arranged on the side of the plate opposite that adjacent the welding torch. During the formation of the weld, gaseous nitrogen escapes through holes in the saddle to cool the protective coat and keep it from melting or volatilizing.