Heat treatment method of bearing

Abstract

The invention relates to a heat treatment method of a bearing. The heat treatment method comprises the following six steps of: heating, insulating, quenching, cleaning, cold treatment and tempering. The heat treatment method is characterized in that before the heating step, a fining treatment step of carbide is arranged; the fining treatment step comprises two steps of forging and spheroids annealing; the temperature of initial forging in the forging steps is 1050-1150 DEG C; the insulating time is 70-90 minutes; the temperature of the final forging and forming is 800-900 DEG C; then the stirring and cooling are carried out in boiling water till the temperature is 300-600 DEG C; the bearing is taken out of water and air-cooled till room temperature; and the spheroids annealing step comprises specific steps of: heating to 790-810 DEG C, insulating for 150-210 minutes under the temperature, air cooling to 680-710 DEG C, insulating for 4-6 hours, cooling till 650 DEG C along with a furnace, taking out of the furnace and carrying out air cooling. The cold-treatment step is carried out in 2 hours after the cleaning steps is finished after quenching, liquid nitrogen is adopted as cooling medium, cooling is carried out till the temperature is minus 70-minus 80 DEG C, insulation is carried out for 1.5-2 hours under the temperature, and returning the temperature naturally till the room temperature. The heat treatment method has the advantage that the service life of the bearing is prolonged by fining carbide particles, improving the hardness and controlling the content of the retained austenite in the metallographic structure.

Description

technical field [0001] The invention relates to a heat treatment method for a bearing, which is mainly used for the heat treatment quenching and tempering process of the bearing ring. Background technique [0002] The main modes of bearing failure are fatigue and wear, and the quality of raw materials, carbide network structure, carbide band structure, decarburization, etc. are important factors affecting the fatigue life of bearings. [0003] The quality of heat treatment has an important and even decisive influence on the service life of bearings. High-carbon chromium bearing steel GCr15 is quenched to obtain a martensite structure, and the martensite has the characteristics of high hardness, high wear resistance, high strength, and certain toughness. However, in addition to martensite, there are retained carbides and retained austenite in the structure after heat treatment, and a certain level of troostite structure is allowed to exist if the effective wall thickness is ...

AI Technical Summary

Problems solved by technology

According to some studies, as the hardness increases, the brittleness of the bearing increases and the fatigue performance decreases. It is not suitable to choose a high hardness value in the bearing processing process.

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