Characteristics of Fretting Wear of LZ50 Steel

The fretting wear behaviors of LZ50 steel in contact configuration of ball-on-flat were carried out under varied normal loads(50~150 N) and displacement amplitudes(2~40 μm).Dynamic analyses in combination with microscopic examinations through the means of the scan electric microscope(SEM) and energy dispersive X-ray spectroscope(EDX) are performed.The experimental results show as follows: The fretting regimes of the LZ50 steel are strongly dependent upon the imposed normal loads and displacement amplitudes;the variations of the friction coefficient in the different fretting regimes are quite different.The running condition fretting map of LZ50 steel was built up,and the dynamic process of fretting wear might be outlined as three running regimes.In the partial slip regime,the fretting scars present a typical morphology of annularity and present slight damages.In the mixed fretting regime,the traces of ploughing and plastic deformation flow can be observed on the fretting scars,and debris generation between the contact interfaces and severer degradation are visible.The wear mechanism during this regime is the combination of the plastic deformation,abrasive wear,oxidative wear and delamination.A thicker debris layer covers in the contact zone in the scar under the condition of gross slip.And the detachment of particles and ploughing are the main phenomena in the slip regime.Therefore,the severe degradation in the slip regime presents the main wear mechanisms of abrasive wear,oxidative wear and delamination.