New Developments in Martensitic Stainless Steels Containing C + N

Abstract

The use of nitrogen in martensitic stainless steels is limited by its solubility. Nitrogen solubility can be increased by alloying with elements such as Cr, Mn, and Mo and the use of pressure, such as in Pressurized ElectroSlag Remelting (PESR). Furthermore, the joint addition of C + N increases their solubility. Solid-state nitriding can be used for case hardening or N-enrichment of steel powders before sintering. However, the resulting stabilization of austenite can be a drawback for martensitic steels. Besides cryogenic treatment below the martensite finish temperature, ausforming, that is, metal working above Ms, could be promising. This contribution gives an overview about latest developments in N-rich martensitic stainless steels.