Abstract: The 42CrMo bearing ring is widely used in industry fields, especially as key components in high-speed rail, motor car and wind power, etc. Based on the cast-rolling compound forming of rings, the hot rolling for centrifugal casting 42CrMo bearing, and subsequent quenching and tempering are studied. The microstructure and mechanical properties of the rolled ring are analyzed, and their evolution laws during quenching and tempering are discussed. The results show that the grain is refined through the whole thickness of the rolled ring, while irregular and equiaxed coarse grains are found near the middle-layer and minimum spread. The values of strength and hardness are high, and plasticity and toughness are low. The fracture appearances of both tensile and impact are characterized by dimple mainly gathered in shear lip, which display cleavage fracture. After tempering at 530 ℃, the carbide does not be found and the plasticity and toughness remain low. A little of fine and dispersed carbide particle is precipitated at 590 ℃ tempered. Also, the mechanical properties satisfy the standardized demands of production. In these conditions, the tensile fracture has a few of dimples with a large diameter, and the impact fracture is smooth with homogeneous dimple than that at 530 ℃ tempered. So a good cooperation between strength and plasticity and toughness for the cast-rolling fabricated bearing ring can be obtained in this study.

Key words: cast-rolling forming, mechanical properties, microstructure, quenching and tempering, 42CrMo bearing ring