Temperature, thermoelectric current and adhesion formation during deep drawing

In sheet metal forming, dissipating forming work and friction lead to a temperature increase, which causes thermoelectric voltages and currents due to the Seebeck effect. Since both temperature and thermoelectric currents influence adhesion formation significantly, knowing their course and maximum values is of great importance. Within this study, several deep drawing experiments with the aluminum alloy EN AW 5083 and the stainless steel X5CrNi18-10 were conducted with an instantaneous measurement of both temperature and thermoelectric currents in situ at the draw ring. Furthermore, the influence of the latter on adhesion formation and punch force was investigated by applying different externally regulated currents between the contact area of tool and sheet metal. The presented results improve the understanding of deep drawing processes and confirm the possibility of reducing adhesions by influencing thermoelectric currents.