Abstract: The vacuum diffusion bonding technology is used to connect the AISI304 austenitic stainless steel and low carbon steel dissimilar materials. Under the condition of constant temperature and pressure， the influence of the bonding time on the microstructure and properties of the AISI 304 austenitic stainless steel and low carbon steel bonded joint was studied. The results show that a good diffusion bonding between the mentioned two materials can be acquired with 850℃ bonding temperature， 10MPa bonding pressure， and 60min bonding time. Also with these parameters， the strength and toughness are higher than the low carbon steel base material level， that the tensile strength reaches 440MPa at the bonding joint， and the tensile fracture occurs at the low carbon steel side. In high temperature environment， carbide segregation phase (Cr₂₃C₆) appears at the interface， decreasing the interfacial toughness. Longer bonding time can effectively prevent the precipitation of harmful compounds Cr₂₃C₆， and enhance the impact toughness up to 120.5J/cm². With this condition， the impact fracture occurs in low carbon steel side.

Key words: austenitic stainless steel, mild steel, vacuum diffusion welding, microstructure, property