Weldability of high nitrogen steels: A review

High nitrogen steel (HNS) have been widely used in many industrial fields in place of stainless steels. As we know, the welding is the main fabricating method of the HNS structural components. In this article, the recent investigations of joining methods of HNS, such as tungsten inert gas welding, melt inert-gas welding, laser welding, laser-arc hybrid welding, friction stir welding (FSW), and brazing method are summarized. First, the effect of nitrogen content in shielding gas, welding wire, and base metal on the evolution of microstructure, mechanical properties, and corrosion susceptibility of fusion welded joints are discussed systemically. Then the existing problem during FSW and brazing process of HNS are analyzed. Additionally, the key issues and future trends in the joining of HNS are proposed. The main purpose of this review is to provide a technical reference and theoretical basis for research and technological development during the welding of HNS.