Consideration of fretting fatigue properties of plasma nitrided En19 steel: Second Prize

Fretting fatigue behaviour of plasma nitrided En19 steel was examined in the present study. It was found that a 10 h plasma nitriding treatment improved the fretting fatigue strength of the steel by 245% and the plain fatigue strength by 70%. However, extending the nitriding time had different influences on fretting fatigue as compared with those on plain fatigue. Long nitriding times resulted in higher plain fatigue strength, but this was not so in fretting situations. The present work demonstrates that short time nitriding is as effective as long time nitriding in improving the fretting fatigue strength of the investigated steel. The results can be explained in terms of the compound layer, the residual stresses, and the strengthening of the materials (increase in microhardness) in the nitrided case.