Bearing steel for automobile wheel hub and manufacturing method thereof

Abstract

The invention provides a bearing steel for an automobile wheel hub and a manufacturing method thereof. The bearing steel comprises the following chemical components by weight: 0.58 to 0.61% of carbon,no more than 0.15% of silicon, 0.87 to 0.95% of manganese, 0.10 to 0.25% of copper, 0.12 to 0.18% of molybdenum, 0.10 to 0.20% of chromium, no more than 0.015% of sulfur, no more than 0.015% of phosphorus, 0.008 to 0.015% of aluminum, no more than 0.0006% of oxygen, 0.006 to 0.015% of nitrogen, no more than 0.0001% of hydrogen and no more than 0.0015% of titanium, with the balance being iron andunavoidable impurities, wherein C%+Mn% / 3 is equal to 0.87 to 0.95, and Al / N is equal to 0.85 to 1.15. The bearing steel has the characteristics of corrosion resistance, fine crystal grains, high purity degree, excellent strength and toughness, etc.; the bearing steel has tensile strength of 800 to 900 MPa, and can guarantee that the hardness of a high-frequency quenched raceway surface reaches 730to 780 HV and the depth of the hardening zone of the raceway surface reaches 2.0 to 3.5 mm.

Description

technical field [0001] The invention relates to a bearing steel, in particular to a bearing steel for an automobile wheel hub and a manufacturing method thereof. Background technique [0002] The function of the automobile hub bearing is to support the car body and guide the rotation of the wheel. It bears both axial load and radial load. With the growing use and usage of automobile hub bearing units, it has now developed to the third generation. The first generation is composed of double-row angular contact bearings; the second generation has a method for fixing the bearing on the outer raceway. Lan, you can simply put the bearing on the wheel shaft and fix it with nuts; the third-generation hub bearing unit uses the combination of the bearing unit and the anti-lock brake system ABS. The hub unit is designed to have an inner flange and an outer flange, the inner flange is bolted to the drive shaft, and the outer flange mounts the entire bearing together. The emergence of ...

AI Technical Summary

Problems solved by technology

[0007] However, simply adding Al to refine the grains often cannot achieve the corresponding fine grain effect; the existing automobile hub bearing steel cannot effectively improve the hardness of the hub bearing raceway surface due to the low carbon content, and the corresponding hub bearing steel bar Said that the excessive carbon deviation between the center and the edge causes the hardness deviation of the hub bearing raceway surface to be greater than 50HV; the purity of the existing hub bearing steel is not well controlled, especially the high content of oxygen and titanium resulting in a single spherical oxide and nitrogen Titanium-type inclusions exceeding 27 μm, causing early spalling and failure of the hub bearing raceway surface

Images