Study on welding parameters and interface of aluminum/steel composite pipe using underwater explosive welding

Welding parameters play a crucial role in determining the quality of welds. In this study, we investigated the motion characteristics of aluminum pipes under underwater explosion loads using theoretical calculations and experimental measurements to obtain welding parameters. We conducted contrasting experiments with varied welding parameters to examine their effect on the aluminum/steel composite pipe interface. Subsequently, we thoroughly analyzed the microstructures and mechanical properties of the joints. The velocity histories predicted by theoretical calculations closely matched our experimental findings, validating the use of these calculations for predicting welding parameters in underwater explosive welding processes. Notably, our observations revealed that at an impact velocity of 510 m/s and a dynamic collision angle of 10.4°, no visible melted layer was detected at the welding interface. However, at lower impact velocities (340 m/s) and smaller dynamic collision angles (6.9°), some interfaces exhibited melted layers, contrary to theoretical predictions of kinetic energy loss. This discrepancy underscores the significant influence of collision angle on the formation of interfacial microstructures, a factor often overlooked in similar studies. Furthermore, the melted layer identified at the welding interface was identified as an intermetallic compound, which resulted in a 10.75% reduction in the bonding strength of the aluminum/steel interface. These findings contribute valuable insights for optimizing the design of underwater explosive welding processes for metal pipes, offering a practical tool for industry applications.