... induction heating machine for pipe and tube, IGBT design, used for pipe and tube induction heating, annealing. 160KW Induction heating for pipe and tube 1. ... and retain period can be preset respectively, to realize a simple heating curve, this model is suggested to use for ... frequency welding.3, metal quenching, annealing, quenching, tempering and heat treatment.4, metal forging, hot forming.5, ...