FIELD: metallurgy.
SUBSTANCE: invention relates to metallurgy, namely to a steel product intended for use at low temperatures. Steel of the product has the following chemical composition, wt. %: C from 0.01 to < 0.3, Mn from 4 to < 10, Al from 0.003 to 2.9, Mo from 0.01 to 0.8, Si from 0.02 to 0.8, Ni from 0.005 to 3, P < 0.04, S < 0.02, N < 0.02, iron and unavoidable impurities are the rest. Steel product satisfies one of three embodiments. In the first embodiment, steel can contain at least one of the following elements, wt. %: Ti from 0.002 to 0.5; V from 0.006 to 0.1; Cr is from 0.05 to 4; Cu from 0.05 to 2; Nb from 0.003 to 0.1; B from 0.0005 to 0.014; Co from 0.003 to 3; W from 0.03 to 2; Zr from 0.03 to 1; Ca < 0.004 and Sn < 0.5, wherein 6 < 1.5Mn + Ni < 8. In the second embodiment, steel can contain at least one of the following elements, wt. %: Ti from 0.002 to 0.5; V from 0.006 to 0.1; Cr is from 0.05 to 4; Cu from 0.05 to 2; Nb from 0.003 to 0.1; B from 0.0005 to 0.014; Co from 0.003 to 3; W from 0.03 to 2; Zr from 0.03 to 1; Ca < 0.004 and Sn < 0.5, wherein 0.11 < C + Al < 3 is satisfied. In the third embodiment, steel can contain at least one of the following elements, wt. %, B from 0.0005 to 0.014; V from 0.006 to 0.1; Nb from 0.003 to 0.1; Co from 0.003 to 3; W from 0.03 to 2 or Zr from 0.03 to 1, and, optionally, at least one of the following elements, wt. %: Ti from 0.002 to 0.5; Cr is from 0.05 to 4; Cu from 0.05 to 2; Ca < 0.004 and Sn < 0.5. Microstructure of the product consists of 2–90 vol. % austenite, less than 40 vol. % of ferrite and/or bainite, the rest is martensite.
EFFECT: product has the required combination of properties of strength and stress at low temperatures.
12 cl, 3 tbl
