Research on the impact velocity of magnetic impulse welding of pipe fitting

Magnetic impulse welding, which is uniquely advantageous in welding heterologous pipe fittings, is a new welding technology based on high-speed magnetic impulse shaping and solid-phase diffusion welding. The impact velocity of the welding points of Al–Fe heterologous pipe fittings was studied by combining numerical simulation and technological test with the assistance of constitutive relations of 3A21Al alloy under a high strain rate. The momentary movement speeds when the outer tube (A1) impacts the inner tube under four different voltages were analyzed to obtain the critical voltage for welding inner and outer tubes. The speed of the welding points of the outer tube noticeably increased with the rise in the discharge voltage. The weld interfaces of both the inner and outer tubes produced regular zigzag waves when the impact velocity reached 350 m/s. The energy spectrum analysis revealed that pipes undergo severe deformation under high-speed impact, and the increased temperature enhances the activity of the atoms among other elements, thus producing a surface mass flow under strong impact and granulated substances.