Metallurgical and mechanical characterization of Inconel 625/SS 304 weldments produced using selective microwave hybrid joining technique

Abstract

In the field of advanced welding, the development of dissimilar material weldments using a microwave hybrid heat source is currently gaining enormous traction. This is because such a heat source could provide volumetric, uniform, and selective heating in a cost-effective way with negligible impact on environment, which would be beneficial to various industries. now Till-date, researchers have used a microwave hybrid heating to join various types of similar as well as dissimilar engineering materials. However, attention has not been paid on the joining and characterization of dissimilar Inconel 625-SS 304 materials using the afore-mentioned heat source as well as the promising applications of the weldments. Therefore, the current paper focuses on the joining of dissimilar materials – Inconel 625 and SS 304 alloys using selective microwave hybrid joining (SMHJ). In SMHJ, Inconel 625 powder is used as a filler material, and SiC powder is used as susceptor to elevate the initial temperature. The produced weldments are characterized using XRD which shows that the joint zone contains numerous carbides and nitrides like NbC, Cr23C6, NbNi, Cr7C3 and FeNi. As a result, the average micro-hardness and UTS of the joint found to be 245 ± 17 HV and 397 MPa, respectively. Moreover, after the tensile test, the fractured surface was studied using SEM. The study reveals that due to the presence of carbides and nitrides in the joint zone, there is observed to be ductile and brittle mode of fracture.