HIGH-STRENGTH PLATE STEEL FOR MAIN PIPES RESISTANT TO HIGH-SULFUR OIL GAS, AND METHOD OF ITS PRODUCTION, AND HIGH-STRENGTH STEEL PIPE USING HIGH-STRENGTH PLATE STEEL FOR MAIN PIPES RESISTANT TO HIGH-SULFUR OIL GAS Russian patent published in 2020 - IPC C22C38/06 C22C38/04 C21D8/02 C21D8/10 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to high-strength plate steel for production of main pipes resistant to influence of high-sulfur oil gas. Steel has chemical composition containing at expression in wt.%: C: from 0.02 to 0.08; Si: from 0.01 to 0.50; Mn: from 0.50 to 1.80; P: from 0.001 to 0.015; S: from 0.0002 to 0.0015; Al: from 0.01 to 0.08, and Ca: from 0.0005 to 0.005, wherein the residue is Fe and unavoidable impurities. Coefficient of hydrogen diffusion at the center of thickness of plate steel makes 5.0×10^-6 cm²/s or more, maximum value of Vickers hardness HV 0.1 at position located 0.5 mm below surface of plate steel is 250 or less, and ultimate tensile strength is 520 MPa or more.

EFFECT: steel has excellent resistance to hydrogen cracking both in the zone of axial segregation, and in the surface layer.

7 cl, 2 tbl, 1 dwg