Investigation of C276 alloy and 316L SS TIG welded joints with ERNiCrMo-4 and ER304 welding wires

To evaluate themetallurgical properties of ERNiCrMo-4 and ER304 welding wires in the Hastelloy C276 and 316L stainless steel lap-welded joints, the analyses of microstructure, hardness, element distribution and mechanical properties were conducted. The results indicate that the Fe-rich zone was found at joint which added ER304 wire. The weld metals (WM) in two types of joints both consist of dendritic crystal and center equiaxed crystal. Besides, a large number of inter-dendrite precipitates were confirmed as p phase and µ phase. A transition zone was found at the interface between WM and 316L base metal as a result of dilution. The WM near the interface has the highest hardness due to the fine crystals here. In the joint added with ERNiCrMo-4, a large quantity of carbides causes a stress concentration and becomes the source of cracks, resulting in a reduction in shear strength.The fracture mode in all shear samples is ductile fracture.