A new tribological system test for integrated hot forming and die quenching of aluminium alloy sheets

摘要

The automotive industry is searching for alternative powertrain and lightweight solutions to meet steadily stricter emission standards and regulations. To leverage the use of high-strength age-hardening aluminium alloys, new processes such as hot forming and in-die quenching are under development in a number of different groups. 0ne of the challenges with in-die quenching is controlling the friction regime stability due to rapidly changing temperatures at both the tool and the blank surfaces under complex deformation modes. In this paper, a cup-based test method is developed and tested for combinations of draw ring materials and lubricants on AA6070 aluminium sheets. Qualitative investigations of formed cups indicate reduced adhesion of aluminium at the tool surface can be obtained by choosing the right combination of tool and lubrication parameters. A correlation between maximum punch force, formed cup height and average Coulomb friction coefficient is observed in both physical experiments and forming simulation.