Fatigue Failures of the 353130B Type Roller Bearings on China Railway Freight Cars
Causes are analyzed to the three shelling failures of railway 353130B type of roller bearings on China 70t grade of freight cars with K5 type of tilting bogie. These bearings are all failed in service lives less than two years, which is quit less than the overhaul inspection interval of 800, 000 km mileage of vehicles and the design life of 2, 000, 000 km mileage. The failures are all originated from the position at the outer ring inboard side nearly to the seal seat. Metallurgical observations reveal that the material chemical composition and microstructures are all in the reasonable range except for the hardness values. This implies that the manufacturing techniques may not match the requirements to lead to the reduction of fatigue strength. Elastic-plastic finite element (EPFE) analysis reveals that the position at the outer ring inboard side nearly to the seal seat is subjected to the maximum equivalent stress amplitude, which well match the situations of failures. In addition, a comparison is made to the bearing on the same axle weight freight cars But K6 type of bogie. Results reveal the maximum stress amplitude for K5 type of bogie is larger than that for K6 type of bogie. This means the bearings failures are relative to the local structures. Therefore, both the manufacturing techniques and the bogie structures should be advanced to improve the bearing service lives.
Z.Y. Shen, M.N. James, W.D. Li, and Y.X. Zhao
L. Chen "Fatigue Failures of the 353130B Type Roller Bearings on China Railway Freight Cars", Advanced Materials Research, Vols. 44-46, pp. 829-834, 2008