To provide a gougingless complete penetration welding method using a high current pulse MAG for a T-joint having an I-shape bevel, a single bevel or a K-shape bevel which does not require a backside chipping work.

The method requires the following conditions when applied for a plate around 17 mm in thickness: (1) a heat input for welding is 1,500-5,000 J/mm; (2) a backside bead leg length is 1.5-6.0 mm; (3) an optimum welding current is in a range of 360±25 A; (4) an optimum welding speed is in a range of 40±10 cpm; (5) an optimum pulse peak voltage is in a range of 40-55 V; (6) an optimum pulse frequency is in a range of around 300-400 Hz; (7) an optimum pulse width is in a range of 1.0-1.5 ms; (8) an optimum target position of wire is in a range of 0 to +1 mm horizontally to the operator side and 0 to +1 mm upward from a root; (9) an optimum moving angle is in a range of 0 to +5°to advancing angle side with respect to a retreating angle of 20°; and (10) an optimum shield gas flow rate is in a range of 20-25 l/min.