基于CuMnCo钎料的YG6C硬质合金与16Mn钢的真空钎焊工艺研究

Study on Vacuum Brazing of YG6C Cemented Carbide and 16Mn Steel with CuMnCo Filler Mental

采用CuMnCo钎料对YG6C硬质合金与16Mn钢的真空钎焊工艺进行研究。通过三点弯曲试验、光学显微镜观察、扫描电镜及能谱分析等手段研究了真空度、钎焊温度和钎缝间隙对钎焊接头组织和性能的影响。结果表明,钎缝中心区为Cu-Mn基固溶体,两侧界面反应区为Fe-Co基固溶体。真空度、钎焊温度和钎缝间隙对钎焊接头的组织和性能有明显影响。高真空条件下钎焊接头的抗弯强度高于中真空条件下钎焊接头抗弯强度。钎焊温度为1095℃时,钎焊接头的抗弯强度最高。钎焊温度过低时,冶金作用较弱,接头强度较低;钎焊温度过高时,钎料流失较多,接头强度也较低。在高真空以及钎焊温度1095℃、间隙为0.2 mm时,钎焊接头的抗弯强度最高。间隙过小时,钎缝中夹杂物较多,接头强度较低;间隙过大时,Fe、Co原子难以通过长程扩散越过钎缝,冶金作用较弱,接头强度也较低。

YG6C cemented carbide and 16Mn steel was vacuum brazed with CuMnCo filler mental. The effects of vacuum degree, brazing temperature and clearances on the microstructure and properties of the welded joints were studied by three-point bending test, optical microscope, scanning electron microscope （SEM） and energy disperse spectroscopy （EDS）. The results indicate that the microstructure contains Cu-Mn based solid solution in the middle area of the brazing seam and Fe-Co based solid solution in the reaction area near the interfaces. The influence of vacuum degree, brazing temperature and clearances on the joints＇ microstructure and prosperities is obvious. The joints＇ bending strength under high vacuum is superior to the joints＇ bending strength under middle vacuum condition. At 1095 ℃, the joint＇s bending strength is highest. When brazing at lower temperature, the metallurgical action is weak, the bending strength is relatively lower. When brazing at higher temperature, filler mental is drained away, the joint＇s bending strength is lower. Under high vacuum condition, when brazing at 1095 ℃ and clearance is 0.2 mm, the bending strength of the joint is highest. When the clearance is narrower, there are more occluded foreignsubstance and the joint＇s bending strength is lower. When the clearance is wider, Fe and Co can＇t implement, long-range diffusion, the metallurgical action is weaker and the bending strength of the welded joint is relatively lower.