The Influence of Temperature on Metallic Wear

The influence of temperature on the wear rate of a particular combination of metals, 60/40 brass on tool steel, has been investigated over the range 20°C to 600°C. Two regimes of wear were found. At low temperatures, extensive intermetallic contact and welding occur, and the wear rate increases with increasing temperature. At high temperatures, however, the wear rate decreases by several orders of magnitude and protective surface films are generated during sliding. The latter reduce both the extent of intermetallic contact and the frequency with which it occurs. A transition between these two regimes of wear also occurs at a critical load, the magnitude of which increases with the temperature. At loads above the transition load, the increase in wear rate with increasing temperature is accounted for by the associated decrease in hardness of the 60/40 brass, and the relationship W=KL/Pm is obeyed, where W is the wear rate, L is the load and Pm is the flow pressure. At loads below the transition load, however, there is no definite relationship between the wear rate, load and flow pressure. It is suggested that in this regime of wear, the main effect of temperature arises from its influence on the reaction rate between the sliding metals and the surrounding atmosphere.