The research is supported by the National Natural Science Foundation of China ( No. 50975015 and No. 51005011 ) ; the China Postdoctoral Science Foundation (No. 20090460186).
A novel ultrafast-convert hybrid pulse variable polarity gas tungsten arc welding process (HPVP-GTAW) is developed. High frequency pulse square-wave current which has a frequency of more than 20 kHz is exactly integ...