The invention aims to provide a quenched-tempered heat treatment method for bearing sleeve
machining. The heat treatment method comprises the steps that (1) pre-heating treatment is carried out, specifically, a bearing sleeve used in the
machining process is made from 20CrMnTi steel, the rough-machined bearing sleeve is preheated to 350 DEG C, and heat preservation is carried out for 30 minutes at a constant temperature; (2) normalizing heating is carried out on the bearing sleeve, specifically, the bearing sleeve which is pre-heated in the step 1 is further subjected to secondary heating to reach 800 DEG C; (3)
quenching and cooling treatment is carried out, specifically, cold water is firstly sprayed on the surface of the high-temperature bearing sleeve to carry out cold
water cooling, when the temperature of the bearing sleeve is decreased to 530 DEG C, water spraying is stopped, and then the bearing sleeve is immersed into oil for secondary cooling and then is placed in air to be air-cooled to 120 DEG C; and (4) high-temperature
tempering treatment is carried out. The method has the advantages that the temperature reduction speed in the
quenching process can be decreased, the
temperature difference between inside and outside of the bearing sleeve can be reduced, the surface fracture in the
quenching process can be avoided, the quenching quality can be improved, and the
hardness and the surface
wear resistance of the bearing sleeve can be improved.