METHOD OF MANUFACTURING HIGH-STRENGTH COLD-DEFORMED REINFORCEMENT OF PERIODIC PROFILE Russian patent published in 2024 - IPC C21D8/08 C22C38/46 C22C38/42 B21C1/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to production of steel cold-deformed high-strength reinforcement of periodic profile, produced by method of cold drawing and thermomechanical processing. Steel is melted with chemical composition, weight fraction of elements, %: carbon 0.73–0.76, manganese 0.65–0.75, silicon 0.20–0.30, sulphur not more than 0.010, phosphorus not more than 0.020, chromium 0.18–0.25, nickel 0.08–0.15, copper not more than 0.10, aluminium 0.001–0.005, vanadium 0.09–0.15, nitrogen is not more than 0.010, iron is the rest, wherein ratio of aluminium to vanadium Al/V is 0.007–0.056, and ratio of chromium to vanadium Cr/V is 1.20–2.78. Steel is rolled to produce wire rod. Wire rod is heated in furnace to temperature of 950–990 °C with subsequent isothermal quenching for 85–110 s in molten lead at temperature of 530–560 °C and final cooling with water. Wire rod is etched and cold drawn with total reduction ratio of 60–80% with single reduction of 6–18% to produce a workpiece. A periodic profile is applied on the workpiece and thermomechanical treatment is carried out at temperature of 340–400 °C during plastic deformation by drawing with elongation of 1.0–1.4%.

EFFECT: reinforcement has the required level of mechanical properties, namely strength of not less than 1,670 N/mm², conditional yield strength of not less than 1,550 N/mm², relative elongation at break of not less than 7%, full relative elongation at maximum load of not less than 4% and breakage during operation of reinforcing bars <0.03%.

1 cl, 1 dwg