A Comparative Study on Direct and Pulsed Current Gas Tungsten Arc Welding of 25Cr-35Ni Heat Resistant Steel

Abstract

In this research, 25Cr-35Ni heat resistant steel was welded by ER-NiCr3 Inconel weld metal using pulsed current gas tungsten arc
welding and continuous current gas tungsten arc welding and the effect of these welding processes on the unmixed zone of the steel was
studied and compared. It was observed that when continuous current gas tungsten arc welding was used, due to incomplete mechanical
mixing, an unmixed zone was observed in the interface between the 25Cr-35Ni heat resistant steel and ER-NiCr3 Inconel weld metal. This
region was eliminated using pulsed current gas tungsten arc welding with peak current of 180 A, base current of 60 A, frequency of 10-12
Hz, percentage on time 40 and also grains of weld metal became finer.