Abstract: In view of the problems such as surface soft spots and warping deformation in the process of carburizing and quenching heat treatment of a type of thrust disc ball (tapered) bearing with large diameter resulted in product repair or scrapping, the causes of soft spots and excessive warpage deformation on the surface of the thrust disc workpiece are analyzed, measures such as reasonably increasing the surface carbon concentration, increasing the temperature of the second quenching, adding cold treatment, and improving the heat treatment fixture were proposed. After the process improvement, the surface troostite of the thrust disc workpiece is qualified, the hardness is controlled between 58 and 63 HRC, and the warping deformation is controlled within 0.8 mm, which solves the problem of surface soft spots, controls the warping deformation, and improves the first-time acceptance rate of this type of product, meeting the production needs.

Key words: thrust disc, carburizing and quenching, cold treatment, deformation