... , PEC, Rotary Engineering, Petrol Steel, JSL, CNPC, SINOPEC, CNOOC, CNCEC, etc.Automatic Root Pass, Fill and Cap Pass Welding Machine; automatic pipe welding machine; piping ... Welding efficiency: 280-500D.I/8 Automatic Root Pass, Fill and Cap Pass Welding Machine; automatic pipe welding machine; piping ...