Effect of friction history of workpiece on friction behaviour in metal forming

摘要

This paper describes the influence of friction histories of the specimen surface on frictional behaviour measured by a side-stretching type testing method under lubricated conditions with various loading and unloading patterns of the average contact pressure. The lubricant with lower viscosity has no lubricating effect and the influence of friction histories on frictional behaviour is hardly found. The lubricating effect of the lubricant with higher viscosity is recognized under higher pressures and the specimens with different friction histories give a little higher frictional stress. It is concluded that the influence of the friction history of the specimen surface on the friction law in metal forming is negligibly small.