METHOD OF PROCESSING CARDAN RINGS OF NEEDLE BEARINGS FROM STEEL Russian patent published in 2024 - IPC C21D1/78 C21D9/40 C23C8/22 C22C38/20 

FIELD: machine building.

SUBSTANCE: invention relates to chemical-thermal treatment of cardan rings of needle bearings, which are used in automotive industry and special equipment, and can be used in bearing industry in production of bearings. Method of treating cardan rings of needle bearings from steel includes preheating, case hardening, cooling before quenching, quenching, flushing and tempering, note here that bearing races are machined from steel containing the following components in wt.%: C (carbon) 0.12–0.19, Si (silicon) 0.17–0.37, Mn (manganese) 0.85–1.15, P (phosphorus) <0.03, S (sulfur) <0.035, Cr (chromium) <0.3, Ni (nickel) <0.3, Cu (copper) <0.3, Fe (iron)—the rest, in one thermal unit with a conveyor belt by means of multi-zone heating in a gas-protected chamber for 585±135 min, in the first zone, in which heating is carried out to 890±5 °C, in the second zone—to 935±20 °C, in the third zone—to 940±20 °C, in the fourth zone—up to 940±20 °C, in the fifth zone—up to 940±20 °C, in the sixth zone—up to 845±10 °C using a carburizing agent for atomic carbon saturation, consisting of a mixture of methanol and propane, with subsequent quenching in quenching oil at oil temperature of up to 70±10 °C for 7±5 minutes, washing in a washing solution based on water with the addition of an emulsion agent for cleaning from contaminants, with concentration of 1–3%, as well as a sodium nitrite preservative in amount of 5–10 g/l, at a temperature of up to 50 °C for 17±5 minutes and low-temperature tempering at temperature of 165±5 °C for 150±30 minutes.

EFFECT: providing the required diffusion saturation with carbon, achieving uniformity of the depth of the layer over the area of the product, reducing hardening deformations during processing and reduction of power consumption due to combination of operations on one equipment.

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