Direct current arc welding control method

A DC arc welding control method of welding by alternating a short-circuit period and an arc period, wherein

• the arc period includes at least a first period, a second period, a third period, and a fourth period,
• the DC arc welding control method comprises at least:
• in the first period, raising a welding current flowing through a welding wire to a first current value;
• in the second period, lowering the welding current from the first current value to a second current value with a predetermined time slope;
• in the third period, keeping the welding current at the second current value;
• and
• in the fourth period, raising the welding current from the second current value to a third current value lower than the first current value but higher than the second current value, and then keeping the welding current at the third current value until the fourth period ends;
• the welding wire is fed at a feeding speed constant throughout the short-circuit period and the arc period,
• in the second period, a welding output is under constant voltage control, and
• at least in the third period and the fourth period, the welding output is under constant current control.