METHOD OF MARTENSITE STAINLESS STEEL PRODUCTION Russian patent published in 2009 - IPC C21D6/00 C21D8/10 

FIELD: metallurgy.

SUBSTANCE: after hot treatment and before thermal treatment for tempering by means of quenching from temperature of at least point Ac₁ steel is subject to preliminary softening thermal treatment under the conditions, when softening parametre P, as it will be determined further, is equal at least to 15400, while temperature of softening T is below point Ac₁; also P (parametre of softening) is: P=T(20+log t), where T is temperature of softening [K], and t - is duration of softening treatment (hours). The invention is particularly efficient for martensite stainless steel with composition, where amount of efficiently solved C and N (=[C*+10N*]) exceeds 0.45; also C* and N* are calculated from stated below expressions: C*=C-[12{(Cr/52)×(6/23)}/10], N*=N-[14{(V/51)+(Nb/93)}/10]-[14{(Ti/48)+(B/11)+(Al/27)}/10].

EFFECT: preventing delayed fracture occurring in martensite stainless steel subjected to hot treatment.

7 cl, 2 tbl, 1 ex, 1 dwg