This chapter is devoted to stainless steels containing high-levels of nitrogen. Ni-free stainless
steels and those containing raised levels of manganese are also covered. The problems associated with
nickel and the reasons for developing low-Ni/Ni-free stainless steels using nitrogen and manganese are
introduced. New constitution diagrams for phase prediction of the new high-N (Ni-free) stainless steels
are presented. Recently developed methods for introducing very high levels of nitrogen to stainless
steels are discussed. The effects of nitrogen on mechanical and corrosion properties, together with the
underlying mechanisms, are introduced. Although high-N stainless steels typically contain low/no Ni,
this chapter also discusses briefly high-N, high-Ni grades, whose production has been suggested rather
recently.
Keywords: High-nitrogen steel, nitride, Ni-free stainless steel, Ni-containing stainless steels, high-Ni
stainless steels, phase prediction, fatigue, corrosion, ductile-to-brittle transition, Schaeffler diagram,
modified Schaeffler diagram.
