A novel dynamic self-constrained explosive welding method for manufacturing copper-steel bimetallic tube

This study proposed a dynamic self-constrained explosive welding method to fabricate the copper-steel bimetallic tube without external mold. The mechanical balance of the self-constrained process was carefully revealed by three-dimensional (3D) numerical simulations. Besides, the microstructure evolution, element distribution, and mechanical properties of the copper-steel interface were systematically investigated. Results showed that the dynamic self-constrained system could effectively strike a balance between the inner and outer tubes in terms of stress, velocity, and displacement. The max hoop tensile stress near the outer surface of the base tube was significantly reduced from 535 MPa (in the unconstrained experiment) to 387 MPa avoiding the appearance of radial cracks. The welding interface varied from a nearly straight one via a large wave to an irregularly small wave. Meanwhile, the microhardness test showed a significant increase in the region near the welding interface.