Investigation on structural feature and bonding performance of Hastelloy foil/steel explosive welding composites under different explosive loads

Abstract

Hastelloy foil/steel composite is of most interest in many industrial fields, as it has competitive advantages of excellent corrosion resistance and low cost. Due to the low thermal conductivity and thermal hardening property, traditional fusion-based connection methods fail to provide high-quality Hastelloy/steel composites. Here an improved explosive welding was introduced to prepare this composite, and the effect of the explosive amount was carefully investigated. The characterizations (including optical microscopy (OM), electron backscatter diffraction (EBSD), bending, nanoindentation, and electrochemical corrosion) were conducted to understand the bonding properties, and Smoothed Particle Hydrodynamics (SPH) simulation was used to investigate transient interface behavior. It was found that the self-developed explosive welding was a suitable method to produce superior Hastelloy/steel composites. Under reasonable welding parameters, both the surfaces of Hastelloy and Hastelloy/steel interface exhibited ideal welding patterns without defects, and the composite remained intact under 90° bending loading. The explosive load is a crucial factor determining bonding properties, and the undesirable features like wrinkles and melting area were found to be positively correlated with the explosive load, which reduced the corrosion resistance. This comprehensive research enabled to provide a new perspective for Hastelloy/steel preparation and improve the understanding of explosive welding process behavior.