METHOD OF MANUFACTURING OIL-GRADE PIPES (VERSIONS) Russian patent published in 2019 - IPC C21D9/08 C21D8/10 C22C38/04 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of seamless hot-rolled pipes from medium-carbon low-alloy steel, which are intended for arrangement of oil and gas wells. Proposed method comprises hot deformation of steel pipe billet from steel containing components in the following ratio, wt%: 0.27–0.38 carbon, 0.15–0.37 silicon, 0.85–1.75 manganese, not more than 0.30 chromium, not more than 0.30 nickel, not more than 0.30 copper, 0.02–0.17 vanadium, 0.02–0.05 of aluminum, not more than 0.015 of sulfur, not more than 0.020 of phosphorus, iron and unavoidable impurities – the rest. To ensure high strength properties of pipes, pipe strengthening is carried out according to one version by quenching with heating temperature in range of Ac₃÷(Ac₃+30) °C and subsequent tempering at temperature of 500 °C to Ac₁ with separate furnace heating, and according to another version, in thermomechanical processing in line of pipe-rolling unit performing deformation at temperature above upper critical temperature Ar₃ and subsequent cooling of pipes in air.

EFFECT: disclosed is a method of making oil-grade pipes (versions).

3 cl, 1 tbl