Influence of Cyclic Heat Treatment and Oxygen Content on the Rolling Contact Fatigue of JIS SUJ2 Bearings
In this work, two SAE 52100 grades with different oxygen contents were repeatedly quenched and the influence of this cyclic heat treatment as well as the role of the oxygen content level on the mechanical properties of the material were investigated by rolling contact fatigue tests. The repeated quenching process increased the retained austenite content and had little influence on the material’s hardness. The prior austenite grain size was decreased and consequently, refinement of the martensitic phase in both types of materials occurred. The higher content of the retained austenite (higher fracture toughness) and the refinement of the microstructure accounted for the higher fatigue properties of the repeatedly quenched material. Flaking failure was present in the material quenched only once, after 4.3x107 cycles (higher oxygen content) and 108 cycles (lower oxygen content). Flaking failure did not occur in the samples treated by repeated quenching. The results show the importance of both optimized heat treatment and alloy cleanness for the lifetime of bearing steel.
E. C. Santos et al., "Influence of Cyclic Heat Treatment and Oxygen Content on the Rolling Contact Fatigue of JIS SUJ2 Bearings", Advanced Materials Research, Vols. 217-218, pp. 982-987, 2011