TANDEM GAS METAL ARC WELDING METHOD, AND WELDING TORCH AND WELDING APPARATUS USED IN THE METHOD

摘要

A tandem gas metal arc welding method using a leading electrode and a trailing electrode, which is characterized in that a leading electrode shield gas to be supplied to the leading electrode is a dual-mixed gas of argon gas and carbonic acid or a triple-mixed gas of argon gas, carbonic acid gas and oxygen gas, a trailing electrode shield gas to be supplied to the trailing electrode is argon gas alone, a dual-mixed gas of argon gas and carbonic acid, a dual-mixed gas of argon gas and oxygen gas, or a triple-mixed gas of argon gas, carbonic acid gas and oxygen gas, and the concentration of carbonic acid gas in the trailing electrode shield gas is lower than that in the leading electrode shield gas.