A Two-Stage Variable Pressure Diffusion Bonding for Manufacturing High-Precision Steel Hollow Structural Components

Conventional diffusion bonding is normally conducted under constant bonding pressure, resulting in obvious deformation of the joined component, thereby destroying the internal structures. To address this problem, this study proposed a two-stage variable pressure diffusion bonding to fabricate the high-precision steel hollow structural component. In the first stage, a short-time higher bonding pressure was applied to significantly improve the local micro-plastic deformation of the surface asperity; in the second stage, a lower bonding pressure was used to continuously act on the bonding process. The macroscopic deformation, interfacial characteristics and shear strength were analyzed. Results showed that a well-joined hollow structural component was manufactured, in which a high interfacial bonding ratio of 98.2%, shear strength of 818 MPa close to that of the base material and limited macroscopic deformation of 4.9% were achieved.