Numerical and experimental investigations on the effect of the heating strategy and the punch speed on the warm deep drawing of magnesium alloy AZ31

The present work has been focused on the warm deep drawing process by superimposing a thermal gradient between the blank centre in contact with the punch and the blank flange (which is going to be drawn). Using such a technique the limit drawing ratio of Mg alloys can be dramatically improved. As a case of study, the forming of cylindrical AZ31 cups was investigated. In particular, the attention was focused on the forming temperature (in both the flange region and in the blank centre). Finite element simulations were run in order to investigate the stress and strain distribution in the material determined by the temperature gradient and to validate experimental results. Tests highlighted that a LDR equal to 3.375 is possible when setting the temperature of the blank holder at 230 °C and the punch speed at 6 mm/min.