Evolution of interfacial characteristics and mechanical properties for 316LN stainless steel joints manufactured by hot-compression bonding

In this study, we report a method to manufacture heavy stainless steel forgings using a newly-developed multilayer hot-compression bonding method. In particular, the interfacial healing mechanism and mechanical properties of hot-compression bonding joints under various deformation and holding conditions were systematically investigated. The results indicate that the bonding interface can be hardly healed when holding at 900 degrees C and 1000 degrees C since the interfacial oxides are difficult to decompose at the low temperatures, resulting in poor tensile properties of the bonding joints. As holding temperature increases to 1100 degrees C, the interfacial oxides are partially decomposed, and therefore the interface bonding effect improves with the partial restoration of tensile properties. Especially, after holding at a higher temperature, i.e., 1200 degrees C for 18 h, the tensile properties of the bonding joint with deformation strain of up to 35 % can be fully recovered to the level of the base material, owing to the complete decomposition of broken interfacial oxides. Based on the optimal deformation and holding conditions for interface bonding, a heavy plate with excellent mechanical properties was successfully manufactured using the multilayer hot-compression bonding method.