METHOD FOR MANUFACTURING HIGH-STRENGTH STEEL REINFORCEMENT Russian patent published in 2022 - IPC C21D8/08 B21C1/00 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular, to production of high-strength deformed steel reinforcement for reinforcing, in particular, new generation reinforced concrete railway sleepers for high-loaded and high-speed traffic routes. The method for producing high-strength steel reinforcement includes smelting of steel, rolling into wire rod, heat treatment of the wire rod by heating in a furnace to a temperature of 900 to 940°C, followed by isothermal quenching for 85 to 110 s in a lead melt at a temperature of 530 to 560°C and final cooling with water, etching, cold drawing, application of a deformation, thermomechanical treatment, and cutting of the reinforcement to the specified length. Steel is smelted with a chemical composition, wt.%: carbon 0.78 to 0.82, manganese 0.70 to 0.80, silicon no more than 0.25, sulphur no more than 0.010, phosphorus no more than 0.010, chromium 0.15 to 0.20, nickel no more than 0.10, copper no more than 0.10, aluminium no more than 0.005, boron 0.001 to 0.0025, vanadium 0.040 to 0.060, nitrogen no more than 0.008, iron the rest. The boron to nitrogen ratio B/N is ≤0.4, the aluminium to vanadium ratio Al/V is ≤ 0.125. Cold drawing of the wire rod is executed with a total degree of compression of 60 to 80%, after applying a deformation, thermomechanical processing is conducted on the workpiece by medium-temperature tempering at a temperature of 340 to 400°C during plastic deformation with a degree of 1.0 to 1.4%, producing steel cold-deformed high-strength reinforcement with a strength of at least 1,700 N/mm², a conditional yield strength of at least 1,600 mm², a breaking elongation of at least 8.0%, and breakage of the reinforcing bars in operation of <0.2%.

EFFECT: high-strength cold-deformed reinforcement with a strength of at least 1,700 N/mm², a conditional yield strength of at least 1,600 N/mm², a relative breaking elongation of at least 8.0% is produced; the breakage of the reinforcement bars in operation is <0.2%.

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