Effects of ring groove and gap on tensile strength of magnetic pulse joint of AA5052-steel 20 tubes

Magnetic pulse joining (MPJ) of AA5052 (flying part) and steel 20 (base part) tubes was investigated experimentally, and the effects of ring grooves of base tube and the gap between tubes on the tensile strength of MPJ joint were focused. The results show that high voltage (energy) pulse discharge contributes to an intense tensile strength. The highest tensile strength, which is similar to that of the original AA5020 tube, has been obtained for the joint with two rectangle section ring groove and the fracture happens at the side of aluminum tube in the 45 degree direction. In order to get stable and high tensile strength of MPJ joint, the rectangle section's edges of the ring grooves should be chamfered and an enough space between the base tube end and the lap area is necessary to avoid the shear of flying tube by the high impact on the base tube end. The tensile strength increases firstly and reduces then with the increasing gap between the flying and base tubes. There is a critical gap value for the highest tensile strength and it is 1.0 mm in this work.