Influence of Case Hardness on Pitting Fatigue Strength of Carburized Steel

摘要

In order to elucidate the influence of case hardness on pitting fatigue strength, fatigue tests were carried out with carburized SCr420 steel rollers that tempered at various temperatures to adjust case hardness. The results on 0% specific sliding condition show internal initiation pitting form and the fatigue strength increases with case hardness. The results on -25% specific sliding condition show two pitting forms; internal initiation and surface initiation. In the case of internal initiation on -25% specific sliding condition, the fatigue strength increases with case hardness same as 0% specific sliding condition. The fatigue strength of internal initiation on both specific sliding conditions coincides with the values estimated from shear strength related case hardness. In the case of surface initiation, the fatigue strength decreases with case hardness. It becomes clear that the pitting form showed on -25% specific sliding condition is lower strength form which internal initiation or surface initiation, that relationship depends on case hardness.