METHOD OF HEAT TREATMENT OF RAILWAY WHEELS AND DEVICE FOR DIFFERENTIAL COOLING OF RAILWAY WHEELS FOR IMPLEMENTATION OF METHOD Russian patent published in 2024 - IPC C21D9/34 C21D1/667 

FIELD: metallurgy.

SUBSTANCE: group of inventions relates to metallurgy, namely to thermal treatment of railway wheels. Device for differential cooling of railway wheels contains units of nozzles for sprayer supply of cooling medium, located along the wheel circumference and directed to the cooled surfaces of the wheel: rolling surface, the outer side surface of the rim and the inner side surface of the rim, manifolds hydraulically connected to the nozzle units through the shut-off valves, wherein shut-off valves are made with possibility of pulse or continuous supply of cooling medium to nozzle units, at that, the nozzle units are located along the wheel circumference with gaps to ensure the alternation of active cooling, in which the cooling medium is supplied, and passive cooling, in which the exposure in air is carried out, and the shut-off valves are made with possibility to adjust the ratio of durations of active and passive cooling, drive rollers, providing rotation of horizontally located wheel with adjustable speed, a supply line for supplying a cooling medium, which is hydraulically connected to each of the manifolds through control valves made with possibility of adjusting the flow rate and pressure of the cooling medium supplied to the manifolds, wherein control valves by their second outputs are hydraulically connected to discharge line, positioning mechanisms made with possibility to move units of nozzles and drive rollers to provide cooling of wheels having different dimensions, and an automatic control system for providing a programmed cooling mode. Railway wheels heat treatment method includes wheels cooling for 180-400 s with rotating a horizontally located wheel at an adjustable speed, which is controlled by changing the flow rate and pressure of the cooling medium supplied to the manifolds by means of control valves, according to the programmed mode and by pulse or continuous supply of the cooling medium from the manifolds to the nozzle units by means of shut-off valves, according to the programmed mode, wherein cooling of wheels, including at least four stages, is performed with adjustment of cooling parameters at each stage, after quenching, wheels are cooled in air to ensure uniform cooling to tempering temperature to rule out warpage, subsequent stress-relieving tempering is carried out in a tempering furnace with a controlled temperature regime.

EFFECT: obtaining a wheel metal microstructure of a quenched sorbite-type on the surface and finely dispersed lamellar pearlite to a depth of more than 50 mm from the surface throughout the wheel rim volume, obtaining the required level of mechanical properties, ensuring minimum thermal stresses and minimum warpage of the wheel during the heat treatment process, providing a cooling rate that can be set in a specific and wide operating range, depending on the chemical composition of steel and the profile of the wheel, expansion of the range and smoothness of cooling rates control, increasing the flexibility of cooling intensity control, providing stable repeated modes of heat treatment, allowing to obtain high quality of heat-treated wheels, guaranteeing the required pressure and flow rate of the cooling medium supplied by units of nozzles to cooled surfaces of wheel during the whole process of cooling.

20 cl, 10 dwg, 6 tbl, 2 ex