Dissimilar joining of different grades of ferritic stainless steel: A review

Abstract

In the recent times the power of the industry standard materials has gained a lot with the advancement in technology. To run the power plants at a required temperature and pressure, the demand for the material with high strength, high thermal conductivity and high corrosion resistance increased significantly. The large number of materials that are mostly used in power plants which are operating at high temperature and high pressure are creep strength enhanced steels, nickel based alloys and austenitic stainless steels. To fulfill and to satisfy the strength requirements, lower cost investment and service conditions, dissimilar welding between Stainless steels is required. And here we can see how important is the need joining dissimilar metals in such cases. A successful joining of two dissimilar metals is as strong as the weaker of the two metals being joined using different welding techniques, i.e., having enough and sufficient tensile strength and ductility so that the joint will not fail in the weld. These joints can be used in a variety of different metals and by several welding processes. The filler material and both metals need to be evaluated before choosing the best way to connect the metals. Here the welding process done between steels is TIG welding. Challenges in the current research are to join the different materials without disturbing the properties of parent metals. Some of the frequently occurring problems are: wider HAZ (heat affected zone), Difference in coefficient of thermal expansions, Difference in chemical composition, Multipass welds to weld high thickness materials. Current research deals with the Optimization the TIG Welding Process Parameters using RSM (Response surface Methodology) and To Understand the effect of Process Parameters on Mechanical Characteristics of the dissimilar joints and to carry out Numerical Investigation on the dissimilar welding of Ferritic Stainless Steel by joining the different materials using tungsten inert gas welding.