Prediction of formability extension in deep drawing when superimposing a thermal gradient

In this paper an interesting simple enhancing of formability in deep drawing processes is presented. In the above process, a localised heating of the blank is obtained by using an electric heater. In addition, a cooling equipment ensures a low temperature at the centre of the sheet, in correspondence of the punch acting zone. In this way a decreasing of the material strength is obtained on the flange, causing a reduction of the axial stress on the vertical wall of the part. At the same time the material strength does not change at the bottom part, where the principal stress is applied. In this way a formability enhancing is easily obtained. An accurate justification from a theoretical point of view and a suitable prediction of the limit conditions are given by using a customised FE simulation. An experimental assessment of the analysis has been carried out by using a properly designed and manufactured equipment.