Tube electromagnetic bulging has been given much attention in the last few years due to its high forming limit and small springback in light alloy processing. However, the non-uniform axial deformation exists in the traditional electromagnetic bulging process restricts the continuous development of this metal processing technology. In this paper, a constraint tube is introduced into the driving coil and forming workpiece to alleviate this issue by improving the electromagnetic force distribution through a new forming method based on double-tube electromagnetic topology. Results show that the formed workpiece can achieve better axial deformation uniformity by adjusting the height and electrical conductivity of the restraint tube. In addition, comparative analysis of the electromagnetic force and forming velocity reveals that the length of the axial uniform deformation based on the proposed forming method is 36.3 mm, which is twice the length obtained through the conventional electromagnetic bulging method. The distribution law of the electromagnetic force can be adjusted through the proposed constraint tube, which provides a new innovative idea to improve the electromagnetic force distribution.

Electromagnetic expansion, electromagnetic force distribution, constraint tube, uniform deformation