Effect of Welding Shielding Gas Composition on the Properties of Laser-Arc Hybrid Welding Joint of High Nitrogen Stainless

Abstract In this paper, the microscopic properties and corrosion behavior of laser-arc hybrid welding joint of high nitrogen steel were studied. The electrochemical characterization of the surface layer of the welded joint under different welding shielding gas composition was obtained from the potentiodynamic polarization curve. The micro-corrosion morphology of different areas in the welded joint was analyzed by SEM, and the hardness distribution of the welded joint was measured by MH series digital hardness tester. The experimental results show that the addition of 5% CO2 in shielding gas can improve the corrosion resistance properly, while the addition of 5% N2 can effectively improve its passivation ability and surface hardness. The weld joint with N2 in the shielding gas own a better transition behavior of the overall hardness distribution.