Friction and Wear of Cast Iron under High Sliding Speed and High Contact Pressure. 2nd Report. The Condition of the Transition from Mild Wear to Severe Wear.

Abstract

The dry friction and wear characteristics of cast iron at high sliding speed and high contact pressure are described with a focus on the conditions of transition from mild wear to severe wear and the friction characteristics in the mild wear region. Wear tests were carried out using a pin on-disk test device in which the cast iron pin slid on a mild steel disk, and the variations of the friction force, the wear rate and the temperature rise with the sliding distance were measured. From the experimental results, the following points were clarified. First, the transition from mild wear to severe wear occurs when the friction induced temperature rise of the cast iron pin reaches a certain value which is strongly related to the decrease in hardness of the cast iron pin. Secondly, the mean coefficient of friction in the case of mild wear can be determined from the temperature rise at the transition point or the mean friction power in the mild wear region. It also depends on the PV value, i.e. it decreases with increasing PV value.