Prediction of limits of lubrication in strip reduction testing

Pick-up and galling due to lubricant film breakdown is a severe limitation in cold forming of tribologically difficult metals like stainless steel and aluminium. The present paper describes a method of combined experimental and numerical analysis to quantify the limits of lubrication in a dedicated simulative strip reduction test.

The limit of lubrication is quantified as the threshold drawing length before galling occurs. A numerical model of the test is established calculating tool/work piece interface temperatures and normal pressures. Identifying a critical maximum value of the interface temperature the results show good agreement between numerically predicted and experimentally observed threshold drawing lengths at different test conditions.