Analysis of microstructure and properties of welded joint of high nitrogen steel by hybrid welding

In this paper, high nitrogen austenitic stainless steel was welded by Nd:YAG -MAG hybrid welding technology, the microstructure and hardness distributions of welded joint of high nitrogen stainless steel in different heat input were studied. The investigation results showed that hybrid welding welded joint of high nitrogen steel cross-sectional is 'goblet' shape, the upper part is arc action area, and the lower part of the laser action area. The weld microstructure is consisted of austenite and a handful of ferrite. The hardness distribution of welded joint is not uniform, base metal hardness is the highest, the value is between 330–370 Hv, the hardness of weld is the lowest, the value is between 260–330 Hv. The hardness of welded joint decrease with increasing heat input. There is no soft zone in welded joint.