Fatigue and fretting fatigue of ion-nitrided 34CrNiMo6 steel

This work is concerned with the surface treatment lion nitriding) of fretti ng fatigue and fatigue resistance of 34CrNiMo6. Tests are made on a servo-h ydraulic machine under tension for both treated and non-treated specimens. The test parameters involve the applied displacements delta +/- 80-+/-170 m um; fretting pressure sigma (n) = 1000-1400 MPa; fatigue stress amplitude s igma (a) = 380-680 MPa and stress ratio R = -1. The ion nitriding process i mproves both fatigue and fretting fatigue lives. Subsurface crack initiatio n from internal discontinuities was found for ion-nitrided specimens. (C) 2 001 Elsevier Science Ltd. All rights reserved.