Process parameters, structure and mechanical properties of dissimilar Nimonic 80 A/AISI 316 L resistance welded joints

Abstract

Abstract The effects of welding current and welding time on the shear resistance of spot welded joints of dissimilar Ni-base superalloys and austenitic stainless steels are investigated for expanding the limits of their use in automotive, naval and aerospace industries. The macro- and micro-structural characteristics, microhardness, and shear strength of the welded joints were examined in order to characterize the resulting joints. It was found that the shear resistance of the heterogeneous welded joints reaches values of 742–849 MPa, much higher than the one specific of the weaker material, which is the austenitic stainless steel with low carbon content, AISI 316 L. The diameter of the welded cores increased for higher current and welding time. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD) were used to evaluate the microstructure of the welded joints from the two dissimilar materials.