Double shielded TIG welding method

A new welding method named double shielded TIG welding is investigated, which is applicable to the TIG process, can improve the weld depth/width ratio of conventional TIG weld shape and protect the electrode from oxidation in the welding process. This method uses two pipelines as the structural characteristic. The inner pipeline provides inert gas which can protect the tungsten electrode. The outer pipeline provides mixed gas with both inert gas and active gas which can provides active element to the weld pool so as to obtain the narrow and deep weld shape. The double-shielded TIG welding method not only increases the weld depth/width ratio about 2-3 times larger than the conventional TIG weld depth/width ratio but also avoids the oxidation of tungsten electrode in the weld process.