Development of Powder Metallurgy Nickel Free High Nitrogen Stainless Steels

摘要

Nitrogen alloying in steel may greatly increase the strength and corrosion resistance of the material. This paper introduced some research results of high nitrogen stainless steels (HNS) investigation via Powder Metallurgy process. Nickel free high nitrogen stainless steels (17Cr12Mn2MoN) were investigated via gas atomization and Hot Isostatic Press (HIP) or Metal Injection Moulding (MIM) plus HIP sintering processes. Nitrogen alloying behavior during gas atomization and consolidation processes was investigated. Densification, phase change and nitrogen migration behavior during the processes were studied. Nickel free high nitrogen stainless steels with nitrogen up to 0.6% exhibits high strength and ductility at as-HIPed and solution treated state. After MIM + HIP sintering process, HNS with nitrogen content up to 0.8% showed very high strength and good ductility at solution treated state, with σ_b at 930 MPa, σ_8 at 560 MPa and elongation of 48%. PM HNS exhibited excellent corrosion resistance.