THE INFLUENCE OF SURFACE-ROUGHNESS TEXTURE ON THE TEMPERATURE AND SCUFFING IN SLIDING CONTACT

The influence of the surface roughness value and surface roughness texture on temperature and scuffing was experimentally investigated using a machine in which a flat unmoving specimen interacted with a rotating roller. The frictional force and temperature under scuffing conditions were measured. To measure the temperature, a special system based on an IR technique was designed. The IR temperature measurements enabled an estimate of the temperature at micro-contacts between interacting asperities. Based on experimental data, the effect of surface roughness value and texture on scuffing load, surface temperature and power emitted in the contact was shown. Using an asperity deformation model, the forces in asperity contact were calculated. On the assumption that the heat source moves through the semi-infinite body, the temperature in micro-contact was also estimated. Two types of scuffing were observed: first, global scuffing which occurred mainly for transverse roughness; second, local scuffing which occurred mainly for longitudinal roughness. The global scuffing was an unstable process and was caused by exceeding the critical power emitted in the contact. The local scuffing was caused by high temperature increments which appeared between interacting asperities and which caused local melting of the steel surfaces. The IR measurements and the calculations of local temperatures in the micro-contacts between interacted asperities confirmed these hypotheses.