Improved workability using preheating in the electromagnetic forming process

Abstract

Electromagnetic forming (EMF) is a high-speed method used to shape metals using a high-energy magnetic field generated by a forming coil. In this study, EMF experiments were conducted on heat-treated aluminum pipes in an attempt to improve the workability of the metal, in which the heating temperature was varied. Heating to 200 degrees C and 250 degrees C resulted in deformation displacements of 1 and 5 mm, respectively. Coupled EM-structural numerical analyses revealed that the EM force was lower by 16 % after heating at 250 degrees C due to the reduction in the conductivity of aluminum at higher temperatures, resulting in a higher resistance. However, the flow stress decreased by about 50 % at 250 degrees C. Thus, the increase in displacement despite the reduction in the EM force at higher temperatures indicates that the workability of metals during EMF can be improved with preheating.