Effect of Structural Parameters of Double Shielded TIG Torch on the Fusion Zone Profile for 0Cr13Ni5Mo Martensitic Stainless Steel

The effects of double shielded TIG (tungsten inert gas) torch's structural parameters, including the flow rate ratio between the inner and outer layers of gas and the extended length of the electrode (abbreviated as ELE in this work), on the fusion zone profile have been investigated for 0Cr13Ni5Mo martensitic stainless steel. Results show that the double shielded TIG process yields relatively high penetration of the weld pool in a broad range of the structural parameters. ELE over 3 mm is too large and causes adverse reactions on the protection of electrode. The outer gas with relatively high flow rate or the outer layer with high oxygen content is conducive to the oxygen dissolved into the arc, which results in the oxidation of the weld pool surface and the electrode tip. The double shielded TIG welded metal was tested and presented good impact property.