DENT-RESISTANT COLD-ROLLED STEEL SHEET WITH EXCELLENT DENT RESISTANCE CHARACTERISTICS, DENT-RESISTANT CLAD STEEL SHEET AND METHOD FOR ITS MANUFACTURE Russian patent published in 2024 - IPC C22C38/38 C22C38/28 C22C38/26 C22C38/22 C21D8/02 C23C2/06 C23C2/40 

FIELD: metallurgy.

SUBSTANCE: invention relates namely to the dent-resistant cold-rolled steel sheet used in the automotive industry. The steel sheet contains, in wt.%: from 0.005 to 0.03 of carbon (C), from 1.0 to 2.5 of manganese (Mn), from 0.2 to 0.8 of aluminium (Al), from 0.3 up to 1.5 of the sum of chromium (Cr) and molybdenum (Mo), from 0.001 to 0.01 of the sum of niobium (Nb) and titanium (Ti), from more than 0 to 0.02 of phosphorus (P), from more than 0 to 0, 01 of sulphur (S), the rest is iron (Fe) and inevitable impurities. The sheet has a mixed structure, in which ferrite and martensite are mixed, and contains precipitates of non-ferrous metals. The average interfacial distance of martensite ranges from 2 mcm to 5.5 mcm, and non-ferrous metal precipitates have an average interparticle distance of 0.05 mcm or more. The sheet has a yield point (YP) of 195 MPa or more, a tensile strength (TS) of 340 MPa or more, an elongation (El) of 33% or more, and a bake hardening degree (BH) of 40 MPa or more.

EFFECT: cold-rolled steel sheet having excellent dent resistance properties.

15 cl, 5 dwg, 5 tbl