Isij International | 2019
Effect of Brazing Temperature on Microstructure and Mechanical Property of High Nitrogen Austenitic Stainless Steel Joints Brazed with Ni–Cr–P Filler
Abstract
High nitrogen austenitic stainless steels (HNS) are a promising structural materials which can obtain the stable austenite by using nitrogen as alloying element.1,2) The addition of nitrogen improves its strength and corrosion resistance without the sacrifice of ductility or toughness at the same time.3) Therefore, HNS possesses great potential to take place of the widely used 304 or 316 austenitic stainless steels for application in many fields, such as biomedicine, automobile parts, ocean engineering, energy, chemical and military industries.4,5) However, welding and joining is an important issue during the process of industrial application of HNS. Fusion welding such as shielded metal arc welding,6,7) gas tungsten arc welding,8,9) laser welding,10,11) is widely used for joining HNS. However, several shortcomings can often be observed during fusion welding, such as N2 pores and hot cracking. Therefore, it is indispensable to choose the type of filler metal or flux and control the welding parameters carefully. Friction stir welding (FSW) and friction welding are both solid state welding processes, which are favorable for decreasing the nitrogen loss and improving the strength of HNS joints.12,13) However, friction welding has certain limitations for joints configuration. Brazing is an appropriate method to join complex shape components,14) which is favorable for enhancing the design space for components and structures. In addition, brazing is free of the usual defects caused by fusion welding. Effect of Brazing Temperature on Microstructure and Mechanical Property of High Nitrogen Austenitic Stainless Steel Joints Brazed with Ni–Cr–P Filler