Microstructure and Mechanical Properties of Steel/Lead Bi-Metal Tubes Produced by Magnetic Pulse Welding

According to the binary phase diagram, Fe-Pb are immiscible under equilibrium conditions and are hard to metallurgically bond. To solve this problem, in this work, the instantaneous high-temperature and high-pressure environments generated during electromagnetic pulse welding (MPW) were utilized to achieve the miscibility of Fe and Pb, enabling the effective bonding of Fe-Pb bi-metallic tubes. The effects of MPW parameters, including discharge voltage and radial gap, on interfacial bond strength and microstructure were analyzed. Optimal bonding occurred at 10.5 kV discharge voltage and a 1.6 mm radial gap, forming a continuous transition layer. Lower energy input reduced bond strength, while excessive energy caused shear deformations. Microstructure analysis revealed that the diffusion zone significantly enhanced the bond strength. Measured bond strength values were 7.6 MPa at optimal conditions. These results demonstrate that MPW is a feasible method for fabricating Fe-Pb bi-metal tubes, offering a promising way for immiscible metals metallurgical welding.