Microstructure and mechanical properties of double pulse TIG welded super austenitic stainless steel butt joints

Abstract The primary objective of this study is to analyze the effect of double pulse tungsten inert gas (DP-TIG) welding on microstructure and mechanical properties of super austenitic SMO 254 stainless steel joints. The butt joints of SMO 254 steel were made using ERNiCrMo-10 filler metal. The microstructural characteristics of different regions of joint were analyzed using optical microscope, scanning electron microscope, X-ray diffraction analysis, and energy dispersive spectroscopy. The micrograph of weld metal showed finer equiaxed grains at the middle of weld metal and columnar grains near the weld interface. The SMO 254 steel joints showed the tensile strength of 636 MPa, ductility of 35 %, and impact toughness of 52 J. The fractured surfaces showed ductile mode of failure of joints.