HIGH-STRENGTH CORROSION-RESISTANT SEAMLESS PIPE FROM OIL-FIELD RANGE AND METHOD OF ITS PRODUCTION Russian patent published in 2020 - IPC C22C38/48 C21D9/08 F16L9/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of high-strength alloyed corrosion-resistant steels used for production of seamless tubing and casing pipes used for oil and gas production, which are used in aggressive media containing carbon dioxide and hydrogen sulphide, and operating at great depth under conditions of low temperatures. Said steel contains, wt%: carbon not more than 0.17, silicon 0.30–0.50, manganese not more than 0.40, chromium 4.5–5.5, molybdenum 0.30–0.90, vanadium 0.02–0.08, niobium 0.02–0.08, aluminum 0.02–0.05, nickel from 0.01 to 0.25, iron and unavoidable impurities – the rest, wherein as unavoidable impurities it contains not more than 0.01 of sulfur and not more than 0.01 of phosphorus. For steel components the following condition is met: 25×Mn×S×Cr≤0.5, where S is absolute value of sulfur content, wt%, Cr is absolute value of chromium content, wt%, Mn is absolute value of manganese content, wt%.

EFFECT: obtaining seamless tubes with yield point from 552 to 862 MPa and having the required corrosion resistance.

6 cl, 2 tbl