Proposing an analytical model for predicting the dimensions of interfacial waves produced in the explosive welding of coaxial cylinders

Abstract

There is an increasing interest in designing the explosive welding process and predicting its results. However, publications concerning explosive bonding have majorly focused on the welding of planar geometries. In this research, a novel analytical equation is presented for predicting the size of interfacial waves formed in the oblique collision of explosively-driven cylindrical surfaces. The experimental data from explosive welding of stainless-steel 316L to carbon steel CK22 tubes are used to validate the proposed model. In addition, the weldability window for this pair of metals is plotted. To calculate the impact angles, a series of numerical simulations are performed, considering three-dimensional (3-D) conditions. In these simulations, to reproduce the tubes’ impact and the detonation process, the Finite Element (FE) and Smoothed-Particle Hydrodynamics (SPH) methods are utilized, respectively. The findings of this research showed that the predictions of the proposed equation are consistent with the experimental data. However, by initiating the wavy-smooth transition, the corresponding values deviate from each other. Furthermore, examining the effects of the explosive load ratio on the collision velocity, it is observed that by reducing the load ratio from 0.552 to 0.14, the collision velocity decreased, linearly, by 77%. On the other hand, it is shown that the placement of design points within the allowable boundaries of the weldability window is the necessary condition for welding. However, to ensure the formation of a wavy interface, the kinetic energy lost per unit area should exceed a critical value. Compared with the conventional models, this critical kinetic energy can more accurately predict the initiation of the wavy-smooth transition process, for it considers the effects of varying thickness of the flyer tube. The value of the critical kinetic energy for the investigated pair of steel tubes, in this research, equals 515 J/cm2.