Effect of humidity and vibration on the friction and wear properties of mild steel

Abstract

Friction and wear properties of mild steel are tested in a pin-on-disc type apparatus. The effects of vibration on friction and wear of mild steel are taken into consideration. An experimental setup is designed and fabricated by which the friction co-efficient of mild steel plate is measured. During the experiment, normal load, speed, vibration, relative humidity and surface-finish of disc are varied. Effects of the above parameters on friction and wear properties of mild steel are measured. Two types of surface-finish ('as-turned' and 'as-ground') are considered for disc sample. Friction co-efficient is measured as the ratio between horizontal and normal forces. Wear rate is measured by taking weights before and after abrasion loss of mass. It is observed that the friction co-efficient increases linearly with duration of rubbing upto a certain time and becomes constant afterwards. Both the friction co-efficient and the wear rate increase with the decrease of relative humidity. Friction co-coefficient remains almost constant with normal load. But wear rate increases with increasing normal load and increasing linear velocity. Rate of increase of frictional co-efficient is more at lower linear velocity than that at higher linear velocity. Values of friction co-efficient and wear rate also depend on the type of surface-finish. In these experiments, for 'as-ground' surface, wear rate was found to be 44% and friction coefficient was found to be 40% to 45% less than that for 'as-turned' surface. The difference of frictional co-efficient and wear rate of vibrating and non-vibrating plates increase with the increase of frequcncy of vibration.