HIGH-STRENGTH STEEL PLATE FOR ACID-RESISTANT PIPELINE, AND METHOD OF PRODUCING STEEL PLATE, AND HIGH-STRENGTH STEEL PIPE, IN WHICH HIGH-STRENGTH STEEL PLATE IS USED FOR ACID-RESISTANT PIPELINE Russian patent published in 2022 - IPC C22C38/12 C22C38/14 C22C38/22 C22C38/24 C22C38/26 C22C38/28 C22C38/38 C22C38/44 C22C38/46 C22C38/48 C22C38/50 C22C38/58 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to high-strength steel plate used for production of acid-resistant pipeline. Plate has a chemical composition containing the following 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; Mo: from 0.01 to 0.50; Ca: from 0.0005 to 0.005; at least one component selected from a group consisting of Nb: 0.005 to 0.1 and Ti: 0.005 to 0.1, optionally at least one component selected from a group consisting of Cu: 0.50 or less, Ni: 0.10 or less, Cr: 0.50 or less, V: from 0.005 to 0.1, Zr: from 0.0005 to 0.02, Mg: from 0.0005 to 0.02 and rare-earth metal: from 0.0005 to 0.02, the rest are Fe and unavoidable impurities. Microstructure of steel at depth of 0.25 mm from the surface of the steel plate is a bainitic microstructure having a dislocation density of 1.0 × 10¹⁴ to 7.0 × 10¹⁴ (m^-2). Vibrations of Vickers hardness at depth of 0.25 mm from the surface of the steel plate make 30 HV or less, and tensile strength is 520 MPa or more.

EFFECT: plate has high resistance to hydrogen cracking and high resistance to sulphide corrosion while maintaining high strength, viscosity and weldability.

3 cl, 1 dwg, 2 tbl