Fatigue property evaluation of bearing steels issued from rotary continuous casting^*

Évaluation des proprietes de fatigue des aciers a roulement issus de coulee continue rotative

Abstract

The most essential in-service characteristic of bearing steel is a good rolling contact fatigue endurance, which is directly related to the inclusion cleanliness. This paper presents a fatigue test methodology and the complementary analysis of the inclusion content performed to estimate, qualify, and control the quality of these materials. For this approach, flat washer (F.B.) tests are initially performed to check the global quality level and the homogeneity of the product. These results are subsequently qualified on tests on actual bearings. This approach was used for the development of the bearing steels produced by rotary continuous casting at the Ascometal Les Dunes plant. Results obtained showed that the quality of the material thus obtained is at least equivalent to that of high quality bearing steel issued from the ingot cast route. Results obtained using the same methodology have indicated that low sulfur content material would appear to be an attractive way of improving the fatigue properties of the product, and particularly their homogeneity throughout the section.