Ferritic - martensitic stainless steel having strain-induced martensitic phase.

摘要

The present invention relates to a ferritic-martensitic Mn-Cr-Ni-N-steel in which the austenite phase is transformed into martensite at cold deformation so that the steel obtains high strength with maintained good ductility. The distinguishing feature is an alloy analysis comprising max 0.1 % C, 0.1 - 1.5 % Si, max 5.0 % Mn, 17 - 22 % Cr, 2.0 - 5.0 % Ni, max 2.0 % Mo, max 0.2 % N, balance Fe and normal amounts of impurities whereby the ferrite content is 5 - 45 % and austenite stability, Sm, expressed as Sm = 462 (% C + % N) + 9.2 % Si + 8.1 % Mn + 13.7 % Cr + 34 % Ni shall fulfill the condition 475 Sm 600.