METHOD OF HEAT TREATMENT OF RAILWAY WHEELS MADE OF STEEL Russian patent published in 2024 - IPC C21D9/34 C22C38/46 C22C38/44 C22C38/42 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to heat treatment of railway steel wheels. Wheels are made of steel containing wt.%: C: 0.48–0.52, Mn: 0.70–0.80, Si: 0.30–0.40, Cr: 0.10–0.20, Ni: 0.10–0.20, V: 0.02–0.04, Mo: ≤0.08, S: ≤0.015, P: ≤0.020, Cu: ≤0.20, Fe is the rest. Wheels are heated to austenitizing temperature, the working layer of the wheel rim is cooled, and subsequent holding of the wheel in air and tempering is carried out. Wheel rim surface layer is cooled down for 300 seconds. Cooling of the rim elements is carried out with water with its flow rate adjustment for separate elements of the rim during the cooling period, respectively: along the wheel rolling circle in the first period for 15 seconds with a water flow rate of 0.013 to 0.016 l/(cm²⋅s), in period of 15 seconds with a water flow rate of 0.016 to 0.030 l/(cm²⋅s), in period of 270 seconds with a water flow rate of 0.030 to 0.070 l/(cm²⋅s). Cooling along the outer side surface of the wheel rim is carried out in the first period for 15 seconds with a water flow rate of 0.020 to 0.030 l/(cm²⋅s), in period of 15 seconds with a water flow rate of 0.030 to 0.045 l/(cm²⋅s), in period of 270 seconds with a water flow rate of 0.045 to 0.060 l/(cm²⋅s). Inner side surface of the wheel rim is cooled with a water-air mixture in the first period for 15 seconds with a water flow rate of 0.003 to 0.005 l/(cm²⋅s), in period of 15 seconds with a water flow rate of 0.005 to 0.007 l/(cm²⋅s), in period of 270 seconds with a water flow rate of 0.007 to 0.009 l/(cm²⋅s), in period of 300 seconds with an air flow rate of 0.013 to 0.020 m³/(cm²⋅s).

EFFECT: increasing the wear resistance of the working layer of the wheel rim due to the formation of a homogeneous structure of thin-plate perlite both on the surface and at the depth of the rim, as well as increasing the mechanical properties of the wheel rim.

1 cl, 5 tbl, 1 ex