Heat input and shielding gas effects on the microstructure, mechanical properties and pitting corrosion of alternative low cost stainless steel grade 202

Abstract

The intention of this study was to create information for welders and engineers in regards to 202 (200-series) austenitic grade stainless steel as a low cost alternative for the replacement of 300-series stainless steel. The content of this paper discusses the effects of different heat inputs and different nitrogen mixes in the argon shielding gas using the GTA welding process. This paper discusses the effects to the microstructure, mechanical properties and corrosion resistance of the weld metals. The results of this study indicate that reducing the heat input when welding caused the width of the face and root of the weld bead to be narrower. The microstructure (delta ferrite, dendrite length and interdendrite spacing) tended to decrease and the hardness and ultimate tensile strength tended to rise. In addition, the percentage of elongation decreased while the pitting corrosion resistance increased. An increase of nitrogen in the argon shielding gas did not cause the width of the weld bead to change. However, the volume of delta ferrite, dendrite length and inter-dendrite spacing reduced and the hardness and ultimate tensile strength increased. The percentage of elongation was shown to decrease and the pitting corrosion resistance tended to increase. The test results of this work focused on increasing productivity and reducing the cost of production from the use low nickel stainless steel in the fabrication industries of Southeast Asia.