Influence of absorbed nitrogen on microstructure and corrosion resistance of 2205 duplex stainless steel joint processed by fiber laser welding

After N2 was added into shielding gas, nitrogen content was increased at upper section and central section of laser weld metal. When shielding gas was pure nitrogen, the microstructure of weld cross-section tended to be homogeneous, its corresponding austenite content was over 40%. The formation of allotriomorphic and penniform austenite was promoted remarkably. The shielding gas of nitrogen was helpful to enhance the corrosion resistance of weldment in 3.5 wt.% sodium chloride (NaCl) solution.