Inhomogeneous deformation behaviors of oblique hole-flanging parts during electromagnetic forming

The electromagnetic flanging of oblique hole-flanging parts is characterized by inhomogeneous deformation, which is closely related to the final forming quality of workpieces. In this work, the inhomogeneous deformation behaviors of a workpiece formed by electromagnetic flanging, whereby an initial blank made of annealed 2219 aluminum alloy with a circular precut hole is formed into an oblique hole-flanging part, are investigated and the influence mechanism is revealed by conducting numerical simulation. A comparison of the forming process for three typical radial deformation regions along the circumferential directions of 0°, 90°, and 180° is made. The results show that during the electromagnetic forming (EMF) of the oblique hole-flanging parts, the deformation region along Path 90° deforms fastest and impacts the die first at the maximum velocity. The deformation region along Path 180° impacts earlier than that along Path 0°. The resulting flanging angle of the workpiece is lower than the target flanging angle with a maximum deviation of approximately 4.8°, and the forming height distributes as a wavy pattern along the circumference. In the EMF of oblique hole-flanging parts, the direct influence factors responsible for the inhomogeneous deformation behaviors of the workpiece include the deformation requirement, area of the deformation region, and electromagnetic force. The inhomogeneous deformation behaviors are essentially due to the uneven deformation requirement. The area of the deformation region is the most important factor influencing the inhomogeneous deformation behaviors, with the electromagnetic force having a significant influence as well. Based on the findings, process parameters can be optimized to control the inhomogeneous deformation behaviors and to realize the precision EMF for nonaxisymmetrical, irregular parts.