STEEL MATERIAL, STEEL PIPE FOR OIL WELL AND METHOD FOR PRODUCTION OF STEEL MATERIAL Russian patent published in 2019 - IPC C22C38/54 C22C38/32 C21D8/10 C21D9/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to steel material used for production of steel pipes of oil wells. Material has a chemical composition consisting of, wt%: C: from 0.25 to 0.50; Si: from 0.05 to 0.50; Mn: from 0.05 to 1.00; P: 0.025 or less; S: 0.0100 or less; Al: from 0.005 to 0.100; Cr: from 0.30 to 1.50; Mo: from 0.25 to 1.50; Ti: from 0.002 to 0.050; B: from 0.0001 to 0.0050; N: from 0.002 to 0.010; O: 0.0100 or less; V: from 0 to 0.30; Nb: from 0 to 0.100; Ca: from 0 to 0.0100; Mg: from 0 to 0.0100; Zr: from 0 to 0.0100; Co: from 0 to 0.50; W: from 0 to 0.50; Ni: from 0 to 0.50; Cu: from 0 to 0.50, rest is iron and impurities. Amount of dissolved carbon makes 0.010–0.050 wt%, yield point ranges from 862 to less than 965 MPa, and ratio of yield point to ultimate strength is 90 % or more.

EFFECT: material has high mechanical properties, as well as high resistance to sulphide cracking under stress.

19 cl, 3 dwg, 6 tbl