Fabrication of High Strength High Nitrogen Stainless Steel with Excellent Corrosion Resistance and Its Mechanical Properties

A project called STX-21 started in 1997 at National Research Institute for Metals (NRIM) for research and development (R&D) of ultra steels for the next century. One of the themes was ‘‘Development of steels for structures in marine and offshore environments.’’ The objective of this research is to develop a resourcesaving type austenitic stainless steel with highly corrosion-resistant properties in seawater. Two key techniques were adopted for this research. One is high nitrogenaddition, and the other purification of the material. In this study the first Japanese pressurized-electro-slag remelting (P-ESR) furnace was developed at NIMS to attain both high nitrogen-addition and purification of materials simultaneously. By using this facility, high nitrogen-bearing stainless steel of more than 1mass% was successfully fabricated without the addition of manganese. In the present study,