PURPOSE: To make it possible to perform MIG welding with an alternating current and to improve the quality of MIG welding, by using a gas composed of a specified component, such as Ar, He, etc., as the shield gas, and by using a complex wire having special slag making material containing oxides, etc, of alkali metal element, etc. as the electrode.
CONSTITUTION: A gas composed of 100W20% Ar or He or their mixture, the rest of CO2 or O2 or their mixture, and unavoidable impurities, is used as the shield gas, and a complex wire containing active metals, such as alkali metal element, alkaline earth metal element, rare earth element, etc., their oxides or fluorides, and slag making material having an arc stabilizing effect (contaning 1W15% wt% TiO2 basing on the weight of the wire, specified amount of simple substance or oxide of Na or K, and a specified amount of SiO2 when necessary) is used as the electrode and welding is made with an AC arc. It may be possible that a plural number of the above-mentioned electrode units are distributed in tandem with a specified distance and welding is made at once with the AC arc.
KATSUMOTO NORIO
NAKANISHI MUTSUO
