STEEL FOR HARDENING IN A STAMP AND A PART HARDENED IN A STAMP MADE OF SUCH STEEL Russian patent published in 2019 - IPC C21D8/02 C22C38/38 

FIELD: metallurgy.

SUBSTANCE: invention relates to a steel part hardened in a die used for making structural parts or safety elements of vehicles. Said steel contains, wt. %: 0.062≤C≤0.095, 1.4≤Mn≤1.9, 0.2≤Si≤0.5, 0.020≤Al≤0.070, 0.02≤Cr≤0.1, wherein 1.5≤ (C + Mn + Si + Cr) ≤2.7, 0.04≤Nb≤0,060, 3,4 x N≤Ti <8 x N, wherein 0.044m≤ (Nb + Ti) <0.090, 0.0005≤B≤0.004, 0.001≤N≤0.009, 0.0005≤S≤0.003, 0.001≤P≤0.020, optionally 0.0001≤Ca≤0.003, balance is Fe and unavoidable impurities. At least 95 % of volume hardened in die part has microstructure including in parts of surface: less than 40 % bainite, less than 5 % austenite, less than 5 % ferrite, the rest is martensite, wherein said martensite consists of fresh martensite and self-tempered martensite.

EFFECT: steel has high strength characteristics, plasticity and weldability without considerable softening in heat-affected zones.

34 cl, 7 dwg, 7 tbl, 4 ex