Application of Self-Heating Method to Estimate Fatigue Limit of 42CrMo4+QT Steel under Fretting Fatigue Conditions

This paper explores the use of the self-heating method based on thermal imaging to estimate the fatigue limit of 42CrMo4+QT steel under fretting conditions. Square test specimens were subjected to cyclic axial loading and fretting contact conditions induced by two types of pads to simulate varied contact slips and temperatures. Fatigue limits from conventional S-N curves were compared to those from the self-heating method. Although the obtained results are in relatively good agreement, a numerical correction was applied to isolate frictional heating effects due to presence of contact. The corrected self-heating curves theoretically represent the plain fatigue problem for which the self-heating method was developed. However, this additional step did not improve accuracy. The results suggest that thermal imaging data can be used directly, without correction, to evaluate the fatigue limit under fretting conditions effectively.