HIGH-STRENGTH HOT-ROLLED STEEL CHARACTERISED BY EXCELLENT SCALE ADHESION AND METHOD FOR MANUFACTURE THEREOF Russian patent published in 2022 - IPC C22C38/50 C22C38/54 C22C38/58 C21D8/02 C21D9/46 B21B3/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely, to a high-strength hot-rolled steel sheet used for manufacturing large-sized industrial machines. The sheet has a composition including components, in wt.%: 0.06 ≤ carbon ≤ 0.18, 0.01 ≤ nickel ≤ 0.6, 0.001 ≤ copper ≤ 2, 0.001 ≤ chromium ≤ 2, 0.001 ≤ silicon ≤ 0.8, 0 ≤ nitrogen ≤ 0.008, 0 ≤ phosphorus ≤ 0.03, 0 ≤ sulphur ≤ 0.03, 0.001 ≤ molybdenum ≤ 0.5, 0.001 ≤ niobium ≤ 0.1, 0.001 ≤ vanadium ≤ 0.5, 0.001 ≤ titanium ≤ 0.1, if needed, at least one element from: 0.2 ≤ manganese ≤ 2, 0.005 ≤ aluminium ≤ 0.1, 0 ≤ boron ≤ 0.003, 0 ≤ calcium ≤ 0.01 and 0 ≤ magnesium ≤ 0.010, the rest iron and unavoidable impurities. The sheet has a tertiary scale layer containing, in fractions of the area, a total of at least 50% magnetite and ferrite, wherein ferrite constitutes at least 25%, from 0 to 50% wustite and from 0 to 10% hematite, wherein specified scale layer has a thickness of 5 to 40 mcm.

EFFECT: sheet has a high adhesion of scale with increased corrosion resistance, fine weldability and machinability by cutting.

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