Tribological Phenomena in Metal Forming at High Speed

This paper describes the development of an original tribometer to study the effects of the average speed V, average of friction roll speed and workpiece speed at the entrance of a contact zone, and of the relative sliding speed δV during deformation on frictional behavior in metal forming. The configuration used two rollers and herce rolling may be simulated. Mild steel sheets with a dull surface were used as workpieces. It was revealed that the friction coefficient decreases with an increase of δV or with a decrease of V. It was also confirmed that the increase of δV and the decrease of V promote flattening of the workpiece surface and yieid good performance of the lubrication film.