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采用Cu-Zn钎料感应钎焊不锈钢/铜接头,并利用金相显微镜、扫描电镜、显微硬度计和万能拉伸试验机对钎焊接头的显微组织和力学性能进行了分析。结果显示:钎焊后钎料/不锈钢界面的形貌由一层化合物、沿晶界生长的针状金属间化合物及向晶内生长的二次树枝晶金属间化合物组成。在远离界面的钎料内部还有金属间化合物沿晶界析出。近钎缝区的铜显微硬度明显降低,不锈钢侧硬度降低不明显,钎缝的显微硬度明显增加,这是由于较快的冷却速度导致黄铜钎料出现大量的CuZn相。钎焊接头拉伸断口位于远离钎缝的铜管上,抗拉强度达到260 MPa,显示出良好的力学性能。
The brazing stainless steel / copper joint was induced by Cu-Zn brazing filler metal, and the microstructure and mechanical properties of the brazed joint were analyzed by metallographic microscope, scanning electron microscopy, microhardness tester and universal tensile testing machine. The results show that the morphology of the brazing filler metal / stainless steel interface consists of one layer of compound, acicular intermetallic compound growing along grain boundary and secondary dendritic intermetallic compound growing into the crystal. In the solder away from the interface there are intermetallic compounds along the grain boundary precipitation. The microhardness of copper near the brazing seam area is obviously reduced, the hardness of stainless steel is not obviously reduced, and the microhardness of brazing seam is obviously increased, which is due to the rapid cooling rate leading to a large amount of CuZn phase in the brazing filler metal. Tensile fracture of the brazed joint is located on the copper pipe far away from the brazing seam, and the tensile strength reaches 260 MPa, showing good mechanical properties.