Optimization of TIG welding parameter in dissimilar joints of low nickel stainless steel AISI 205 and AISI 216

Abstract

Abstract Low nickel 200 series grade austenitic stainless steels are popular due to their low price and the welding of these materials is of interest to engineers and fabricators. Therefore, the dissimilar joining of AISI 205 and AISI 216 stainless steels are examined in this paper. The study used a TIG welding process with an ER307 filler metal and stepped up welding speeds with varying mixtures of H2 in the argon shielding gas. The weldments on the weld bead (shape and size), solidification mode (predicted on WRC-1992) and the delta-ferrite content (compared between the predicted and calculated lath ferrite with vermicular ferrite) were examined. The microstructure (volume and formation of delta-ferrite in the austenite matrix), mechanical properties (hardness and tensile strength tests) and pitting corrosion resistance (pitting potential and pitted initial) are also studied. The results indicate that the welding speed can be stepped up from a minimum of 1 to a maximum of 3.5 mm/sec. This parameter affected to an increase weld bead size, delta-ferrite, hardness, tensile strength and pitting corrosion resistance of the weld metals. The role of H2 can help heat collection in the weld pool during welding allowing the welding speed to increase up to a maximum 5.2 mm/sec. This was achieved with a 6 vol.% of H2 in the argon shielding gas. These results can help increase productivity and thus be considered a successful outcome for this work.