Influence of steel cleanliness and heat treatment conditions on rolling contact fatigue of 100Cr6

摘要

The aim of this work is to determine the rolling contact fatigue (RCF) strength of steel AISI 52100 (DIN 100Cr6) as a common bearing steel in different heat treated conditions. In order to study and evaluate the steel cleanliness and its influence on the fatigue behavior the results are compared to AISI L3 (DIN 102Cr6) as a cold-working tool steel containing higher amounts of non-metallic inclusions as a consequence of a different metallurgical processing. In this work experimental results obtained from both materials with martensitic and bainitic microstructures are presented. In addition, the inclusion content in each material was analyzed using extreme value statistics, and the endurance limits are predicted based on the maximum expected inclusion in the maximum loaded volume as a critical crack initiating defect. The predicted RCF values are in good agreement with the experimental results. Irrespective of the microstructure, the hardness after heat treating dominates the endurable Hertzian pressure. The second important parameter, which determines the endurance limit, is the cleanliness of the steel. Furthermore, the crack pattern in the surface and microstructure of the RCF specimens were analyzed by optical microscopy. The results show no microstructural modifications such as dark etching regions or white etching bands. However, the formation of butterflies was detected around non-metallic inclusions in both steels.