HIGH EFFICIENCY WELDING PROCESS FOR STAINLESS STEEL MATERIALS

The high efficiency tungsten inert gas (TIG) welding process has been developed, including active flux welding process, mixed shielded welding process and double shielded welding pro- cess, to increase the weld depth/width ratio (D/W ) of conventional TIG welding method. Compared to the active flux method, mixed shielding method can make penetration deeper and the industrializa- tion can be realized easily due to the simplification in operation. Double shielded method can avoid the oxidation of tungsten electrode. The results of experiment and simulation show that the change of the Marangoni convection direction which arises from the adjustment of the oxygen content in the weld pool is one of the main factors contributing to the increase in TIG weld penetration, and the large D/W ratio can be obtained by adjusting the active element content in the liquid pool. High efficiency TIG welding process is not sensitive to welding parameters (welding speed, welding current and electrode gap) and therefore is suitable to be applied in industry easily.