AISI304/低碳钢真空扩散焊接头组织和性能

采用真空扩散焊接方法连接AISI304奥氏体不锈钢和低碳钢异种材料.在焊接温度和焊接压力恒定的条件下,研究焊接时间对ASTM304/低碳钢异种材料扩散焊接头组织和性能的影响.研究结果表明:在焊接温度850℃,焊接压力10 MPa,焊接时间60 min条件下AISI304奥氏体不锈钢/低碳钢异种材料实现了良好的扩散结合,其强度和韧性均超过低碳钢母材水平.接头抗拉强度达到440 MPa,拉伸断裂发生在低碳钢一侧.在扩散焊高温环境下,界面附近有碳化物偏析现象,析出相为脆硬的Cr23C6,脆硬相的出现导致界面韧性下降,延长焊接时间可有效避免有害化合物Cr23C6的析出,冲击韧性达到120.5 J/cm2,冲击断口在低碳钢一侧.

Microstructure and Performance of AISI304 /Mild Steel Vacuum Diffusion Bonded Joint

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.