Speaker
Description
Electromagnetic forming (EMF), renowned for its high forming speed and strain rate advantages, has been extensively applied in industrial manufacturing, transportation, and other sectors. The principle of EMF involves generating an electromagnetic force on the workpiece using a pulsed magnet, driving the material to undergo plastic deformation. However, traditional solenoid-based forming magnets often produce non-uniform deformation, characterized by excessive bulging at the center of tubular workpieces and insufficient deformation at the ends. This issue arises from the non-uniform distribution of electromagnetic force field generated by conventional coil structures, significantly limiting the application of EMF in tube manufacturing.
Magnetic field shaper (FS), commonly used in magnet technology to control magnetic field configurations, are typically fabricated from highly conductive metal blocks. By leveraging differences in the surface areas of their inner and outer walls, FSs regulate magnetic field distributions. These structures have been extensively applied in high-field magnets and magnetic pulse welding. In this work, a novel convex field shaper (CFS) is introduced into the design of forming magnets to address the uneven electromagnetic force distribution during tube forming. The CFS features a convex structure, where the end sections have smaller surface areas, and the middle section has a larger surface area. This design increases current density at the tube’s ends while reducing it at the center. Since current density is directly proportional to electromagnetic force, this adjustment redistributes the force, achieving a uniform distribution.
The effectiveness of the CFS was validated through both COMSOL simulations and discharge experiments. Results revealed that, after integrating the CFS into the A6061-O aluminum alloy tube electromagnetic bulging system, the current and electromagnetic force distributions followed the desired pattern: higher forces at the ends and lower forces at the center. Compared to conventional systems, the CFS improved the axial deformation uniformity by approximately threefold, significantly enhancing the overall deformation uniformity. Further investigations into the effects of circuit parameters on tube displacement and axial deformation uniformity were conducted. Simulation and experimental data showed that increasing the discharge voltage led to greater tube displacement; however, an optimal voltage value was identified for maximizing axial deformation uniformity. In conclusion, the proposed CFS-based forming scheme significantly enhances the axial deformation uniformity of tubular components, optimizes the forming profile, and expands the potential applications of electromagnetic forming technology in tube manufacturing processes.
