COATED STEEL SHEET AND PART FROM HIGH-STRENGTH, HARDENED BY PRESSING STEEL AND METHOD OF THEIR MANUFACTURING Russian patent published in 2024 - IPC C21D1/673 C21D8/02 C21D9/40 C21D9/46 C22C38/38 C23C2/02 C23C2/12 

FIELD: metallurgy.

SUBSTANCE: invention relates to coated steel sheets and to parts made from high-strength compaction. Coated steel sheet is made of steel containing, wt %: C 0.26–0.40, Mn 0.5–1.8, Si 0.1–1.25, Al 0.01–0.1, Cr 0.1–1.0, Ti 0.01–0.1, B 0.001–0.004, P ≤ 0.020, S ≤ 0.010, N ≤ 0.010, optionally, one or more of the following elements: Ni ≤ 0.5, Mo ≤ 0.40, Nb ≤ 0.08 and Ca ≤ 0.1, the rest of the composition is iron and unavoidable impurities formed as a result of melting. Coated steel sheet comprises from main part to surface of coated steel sheet: main part with microstructure, containing in fractions of surface 60–90 % of ferrite, remaining part is made up of martensite-austenite islands, pearlite or bainite, wherein said main part is covered with a decarbonized layer containing in the upper part a layer of ferrite with thickness of 1–100 mcm, and a coating layer of aluminum or aluminum alloy.

EFFECT: coated steel sheet is characterized by combination of high mechanical properties with tensile strength exceeding 1,500 MPa, bending angle exceeding 70°, as well as with yield strength exceeding 1,250 MPa.

7 cl, 10 dwg, 5 tbl, 1 ex