关键词: 电加热, 电流密度, 加热速率, 轻合金

Abstract: To improve the heating efficiency and reducing the energy consumption, a pulse current heating method for light alloy sheet hot forming has been purposed. Through the heating experiment in combination with the electrothermics theory, the effects of current density on the heating rate and the final temperature of the different metals have been investigated systematically. The temperature distribution became homogeneous by installing the resistance heat slice between the electrode and the heating blank. In the microscopic aspect, the effects of current density on the crack, cavity and the grain size of the material have been investigated briefly by the finite element method and metallographic microscopic analysis method. The results shows that the grain of the alloy has no obvious grown up, and the defects of the alloy have been got certain inhibition during the heating process because of the heavy pulse current. Aiming at a certain AZ31 Mg alloy superplastic forming process, the parameters of the pulse current have been determined. Through the results, the heating efficiency has been increased and the energy consumption has been reduced.

Key words: Current density, Electric heating, Heating rate, Light metals