The Influence of Hydrogen Addition to Argon as a Shielding Gas on the Fatigue Performance of TIG Welded AISI 304 Stainless Steel

摘要

In this study, AISI 304 austenitic stainless steel sheets are joined through TIG welding under various shielding media. Bending fatigue, notch impact and bending tests are performed on the joined materials. Hardness of the joined materials is also determined. The welding processes are carried using pure argon, argon + 1.5% H₂ and argon + 5% H₂ as shielding media at three different welding currents. Both butt and overlap welding processes are carried out at the same welding parameters. The ER 308 L type wire is used as the filler material for all the joints. The highest fatigue and impact strengths are obtained for both types of joints for argon shielding media. The bending test is applied up to 180°, and no tearing, crack or any other bending defects after visual examination of the bended samples are observed. The welding metal gives the highest hardness values, and they are followed by HAZ and base material.