Temperature Effects on Organic Lubricants in Cold Forging of AA1050 Alloy

Abstract

Lubricants have a key role in cold forging when pressures can reach extreme levels, since they contribute to reduce the high frictional forces occurring at the interface between the tools and billet. However, the adiabatic heating due to the high deformation rates may influence their performances with unpredictable consequences on the process stability. The objective of the research work is to investigate the friction behaviour of new environmental-friendly solid lubricants under process conditions with particular attention to the dies temperatures. The case study refers to the impact backward extrusion of AA1050 alloy cans. The newly developed testing set-up allows heating up the dies and the billet in order to reproduce controlled conditions of the tool temperature in the range 20-200° C. By matching the extrusion loads from the experiments carried out at different temperatures and the results of numerical simulations, the friction factors for each lubricant were determined.