Impact of microstructure on high temperature wear resistance

Abstract

In many industrial applications wear at different temperature levels causes a loss of operational reliability. In this view the wear behaviour of two different hard facings used as wear protection were investigated at ambient and elevated temperatures: a Ni-based alloy with tungsten carbide reinforcement and a carbide rich Fe-based complex alloy. The wear resistance at room temperature and elevated temperatures of 300°C and 550°C was investigated in impacting and abrasive environment in specially developed test equipment. Additionally the hot hardness was measured in a newly developed Hot Hardness Test (HHT) at different temperature levels up to 700°C and correlated to the wear behaviour. Wear analyses were conducted by means of calculation of volume loss, optical microscopy (OM) and scanning electron microscopy (SEM) of the wear tracks, respectively. Results show, that wear rates and mechanisms at high temperature can not be directly correlated to wear at ambient temperature, also the material's microstructure has crucial influence on the wear behaviour. Hence the more expensive Ni-based alloy with tungsten carbide reinforcement does not necessarily shows better wear resistance in all environments investigated.