... ,hardening,forging ,annealing and melting High Frequency Induction Preheat Machine for Tube FormingFeatures:1, the company transistor (IGBT) high ... use of large scale integrated circuit digital automatic control, with manual, automatic, semi-automatic, and the lack of heat insulation of ... cold sub-time control functions. 6, the frequency of automatic tracking, stepless power adjustment, easy to use, 10 ...