Problems in Welding of High Nitrogen Steel: A Review

Abstract

High nitrogen steel (HNS) has an excellent tensile strength and impact property due to the solid solution strengthening of nitrogen, which provides a good application prospect in many fields. Fusion welding is one of the main processing methods of HNS, but the process is prone to spatters, serious nitrogen losses, N2 porosities, and poor performances of joints, resulting in the failure of large-scale engineering applications of HNS. In this work, the development of HNS welding is reviewed, and the problems including the droplet transfer instability, N2 porosities, nitrogen losses and poor mechanical properties due to high nitrogen content are discussed. According to previous welding experiences, the adoption of a welding method with a low heat input is proposed, which utilizes powders instead of wires, optimizes compositions in the shielding gas and feeding materials in order to solve the above problems, and improves the mechanical properties of the weld.