Effects of shielding gas on GMAW of 10Ni5CrMoV HSLA steel using high Cr-Ni austenitic wire

The composition of shielding gas was investigated for gas metal arc welding (GMAW) of the 10Ni5CrMoV steel using high Cr-Ni austenitic wire. Adding CO2 into the inert shielding gas can improve the arc stiffness and reduce the incomplete fusion of sidewall. The optimal shielding gas of 40%Ar + 58%He + 2%CO2 was applied into multi-layer multi-pass GMAW of 10Ni5CrMoV steel with austenitic wire. No welding porosity, incomplete fusion and cracks were found in the welding joint. The chemical composition of the deposited metal reached the requirement for forming austenite weld. The highest hardness of welding joint was less than 350 HV and no obvious hardening tendency occurred in the welding joint. The tensile test and impact test indicated that the multi-layer multi-pass welding joint of 10Ni5CrMoV steel using austenitic wire had excellent comprehensive mechanical properties.