Effect of Shielding Gas and Filler Metal to Micro structure of Dissimilar Welded Joint Between Austenitic Stainless Steel and Low Carbon Steel

摘要

Welding of dissimilar metals involves different types of metals which have different chemical composition, mechanical and thermal properties. This paper presents a study on dissimilar metal weld between type 304 stainless steel and SS400 carbon steel. The steel plates were welded by using different filler metals (solid wire, flux-cored wire) and different shielding gases (100%CO2, 90%Ar+10%CO2). Then the weldments were observed by optical microscope, scanning electron microscope and EDX analysis. It seems that the weldments which were welded by using 100%CO2 shielding gas have significant amount of inclusions in weld metal compared to 90%Ar+10%CO2 shielding gas mixture. The EDX analysis shown the inclusions are oxides which consist of some elements (C, Si, Cr, Mn) with O. The weldment which was welded by using 90%Ar+10%CO2 shielding gas mixture and solid wire has much less inclusions in weld metal.