COATED STEEL SHEET AND PART FROM HIGH-STRENGTH PRESS-HARDENED STEEL AND METHOD OF THEIR MANUFACTURING Russian patent published in 2024 - IPC C22C38/38 C22C38/32 C22C38/28 C22C38/26 C22C38/22 C21D8/02 C21D6/00 C21D9/46 C21D1/673 C23C2/02 C23C2/12 C23C2/40 

FIELD: metallurgy.

SUBSTANCE: invention relates to production of coated steel sheets used as material for production of structural parts or safety parts of vehicles. Steel sheet is made of steel with composition containing in wt.%: C 0.15–0.25, 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 at least one of: Mo ≤ 0.40, Nb ≤ 0.08 and Ca ≤ 0.1, the rest is iron and unavoidable impurities. Coated steel sheet comprises a main part, a decarbonized layer covering the main part, and a coating layer of aluminum alloy. Main part of the sheet has a microstructure containing in surface fractions 60–90% ferrite, note here that the rest is represented by martensite-austenite islands, pearlite or bainite. Decarbonized layer in the upper part consists of a ferrite layer with thickness of 1–100 mcm.

EFFECT: parts made from such sheets have a combination of high mechanical properties and a bending angle of more than 70°.

7 cl, 5 dwg, 5 tbl, 1 ex