An assessment of microstructure and mechanical properties of inconel 601/304 stainless steel dissimilar weld

The microstructure and the mechanical properties of dissimilar joints between Inconel 601 superalloy and 304 austenitic stainless steel were investigated in this work. For this purpose, gas tungsten arc welding (GTAW) process was performed using an austenitic (ER304) stainless steel filler metal in two modes of pulsed and constant current conditions in pure (99.999%) argon gas. Furthermore, an autogenous welding (without filler metal) procedure was also carried out for comparison. The microstructure of weldments was investigated using optical and scanning electron microscopy. Tensile tests and micmhardness measurements were carried out to evaluate the mechanical properties. High vacuum FE-SEM investigations revealed that no segregation has occurred in the weld metal. It was found that a decrease in heat input led to a significant grain refinement in the welds, which improved the mechanical properties. Among the welds fabricated with filler metals, welding with pulsed current resulted in superior mechanical properties. Finally, an excellent strength ductility matching (UTS = 485 MPa and Elongation = 39%) was obtained by autogenous welding procedure.