Promoting the interface connection of hot-compression bonded stainless steel via introducing a novel electroshocking treatment

Large billet connected by solid state bonding joints can prevent the metallurgical defects resulting from integral casting. The high-strength connection of the interface is critically important for overall performance. In this study, a novel electroshocking treatment (EST) was introduced before hot-compression bonding to promote the interface connection of 304 stainless steel. The results showed that the ultimate tensile strength of the connection joint significantly increased from 545.0 MPa to 627.3 MPa and became more uniform owing to the EST. Microstructure observation showed that the trace located at the bonding interface was shallower for the samples subjected to the EST. The effect of the EST on the transformation behaviors of interface was investigated. It was found that the mechanical connection partially occurred after the EST. The recrystallization was generated along the interface, leading to a more uniform stress distribution after the EST. In addition, the EST promote the diffusion of oxygen element from the interface to matrix. Consequently, the strength and performance of the bonding joints is significantly enhanced by EST after hot-compression. This study introduces a novel idea for the interface connection of solid-state bonding, which has excellent engineering application prospects for the manufacturing of large billet.