Electromagnetic Pulse Crimping of Al-Tube on DP Steel Rod

Abstract

The electromagnetic pulse crimping is a high energy, high strain rate, high velocity, and green materials joining or surface coating technique. Joining of dissimilar materials is difficult due to their physiochemical properties that are seldom compatible or similar. Therefore, electromagnetic pulse crimping which is solid-state joining technique can be an alternative for joining dissimilar materials. In the present work, composite rods were produced by the electromagnetic pulse crimping technique, which was characterized by a uniform crimping of the flyer tube on the base rod perimeter. The materials used were Al 1050 as flyer tube and dual-phase (DP) steel as a base rod. Numerical simulations were carried out for finding out the optimized parameters for crimping and then experiments were conducted on the optimized parameters. The results obtained from the simulations revealed that for the successful crimping, a minimum value of collision velocity, plastic strain, electromagnetic pressure, and standoff distance must be maintained. The post-process current obtained from the simulations and first peak of the discharge current measured in the experiments was compared. The variation in the maximum value of discharge currents in simulations from the experimental values was found to be 2, 3, and 7% at 2.5, 2.6, and 2.9 kJ of discharge energy. The outer diameter of the successfully crimped samples was measured and compared with the outer diameter obtained from the simulations and found a maximum of 6.6% variation in the simulation value from the experimental value. The optical microscope image was analyzed and it was found that the Al-tube was crimped on the DP steel rod with a negligible gap. Further, pullout tests and hardness tests at the interface were performed to test the strength and hardness of the joints, respectively.