Improved workability using preheating in the electromagnetic forming process

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 °C and 250 °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 °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 °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.