TWO-PHASE STAINLESS STEEL AND ITS MANUFACTURING METHOD Russian patent published in 2019 - IPC C22C38/44 C21D9/08 C21D8/10 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to two-phase stainless steel used in tubular articles of oil and gas field range. Said steel contains, wt%: C: 0.03 or less, Si: 1.0 or less, Mn: 0.10–1.5, P: 0.030 or less, S: 0.005 or less, Cr: 20.0–30.0, Ni: 5.0–10.0, Mo: 2.0–5.0, Cu: 2.0–6.0, N: less than 0.07 and rest – Fe and unavoidable impurities. Steel has structure comprising 20–70 % phases of austenite and 30–80 % of ferrite phase relative to volume fraction, yield point YS 655 MPa or more and energy absorption vE_-10, which is 40 J or more when measured by the Charpy impact test at test temperature of -10 °C.

EFFECT: steel has required resistance to carbon dioxide corrosion, resistance to corrosion sulphide cracking under stress and resistance to sulphide cracking under stress.

10 cl, 1 dwg, 2 tbl