HIGH-STRENGTH STEEL SHEET FOR ACID-RESISTANT MAIN PIPE AND METHOD OF ITS MANUFACTURE, AND HIGH-STRENGTH STEEL PIPE USING HIGH-STRENGTH STEEL SHEET FOR ACID-RESISTANT MAIN PIPE Russian patent published in 2023 - IPC C22C38/00 C22C38/12 C22C38/58 B21B45/02 B21B45/06 B21B37/74 B21B1/26 C21D8/02 

FIELD: pipe production.

SUBSTANCE: invention relates to a steel sheet for an acid-resistant main pipe. The sheet has a chemical composition containing in % by weight, C: 0.020–0.080, Si: 0.01–0.50%, Mn: 0.50 - 1.80, P: 0.015 or less, S: 0.0015 or less, Al: 0.010 - 0.080, N: 0.0010 - 0.0080, Mo: 0.01 - 0.50 and Ca: 0.0005–0.0050%, the rest is Fe and unavoidable impurities. The proportion of magnetite in the scale present on the surface of the steel sheet is 50 mass% or more, the highest Vickers hardness at a position 0.25 mm below the surface of the steel sheet is 230 HV or less. The tensile strength of the steel sheet is 520 MPa or more.

EFFECT: sheet is resistant to corrosive environments and environments with low partial pressure of hydrogen sulfide below 1 bar.

3 cl, 1 dwg, 3 tbl, 31 ex