Effect of pitting corrosion on similar and dissimilar alloy welded joints

Abstract

The present study has been carried out to develop an understanding of GTAW process with heterogeneous base and filler metal compositions. Austenitic stainless steel AISI 316L and high-strength low-alloy CrMoV steel were welded using Inconel 625. To ensure weldability, all joints were nondestructively evaluated by dye penetrant and radiographic testing. Pitting as a defect, in next was simulated on weld bead surface through 1.5-mm-deep mechanically drilled holes of 1 mm diameter. Transverse tensile properties in similar and dissimilar cases and microhardness were studied and correlated with microstructures. AISI 316L in all cases has shown acceptable mechanical properties in the absence of pitting, but a drastic decrease has been found in severe pitting case. Subject defect seems to have a marginal impact on UTS and total elongation on CrMoV steel. The weldments of dissimilar joint have shown peak hardness and produced failure region in both pitting and without pitting cases during tensile testing.