毛细管板接头真空电子束钎焊工艺

应用自制柔性化电子束钎焊系统对毛细管板接头的钎焊工艺进行了研究，探讨了钎焊工艺参数对钎料扩散深度以及钎脚高度的影响。结果表明：随着电子束输入功率或功率密度的加大，钎料向毛细管壁的扩散深度逐渐增大，钎脚高度的增长趋势显著。在一定范围内，钎料扩散深度及钎脚高度随钎料量及装配间隙的增加而增大。工件表面状态对钎脚高度的影响规律是：铰制过的试板，最有利于钎料铺展，钎脚高度最高，酸洗的试板次之，未经任何处理的试板钎脚高度最低。电子束钎焊的优化工艺参数为：加速电压60kV，束流6．5nA，加热时间37s，钎料质量25mg，聚焦电流654mA，装配间隙0．027mm。

Vacuum Electron Beam Brazing Technology of the Capillary Tube-sheet Joints

The brazing technology for capillary tube-sheet joints has been studied using a self-made flexible controlling equipment of vacuum electron beam brazing. The effects of processing parameters on the diffusing depth of brazing filler metals and the height of brazing toe were analyzed The diffusing depth became higher and the height of brazing toe increased obviously with increasing the beam power or power density. In a certain range, the diffusing depth of the brazing filler metals and the height of brazing toe increased with adding the mass of the filler metals or enlarging the fit-up gap. For the specimens whose tube-sheet holes were reamed, it was highly advantageous for the brazing filler metals to wet the base metal. With all other conditions being equal, the brazing toes of pickled specimens were lower than those of the reamed specimens, and it would have the lowest brazing toe if without any treatment The optimized brazing parameters are as follows. High voltage 60 kV, beam current 6. 5 mA, heating time 37. 5 s, mass of the filler metal 25 mg, focusing current 654 mA and the fit-up gap 0. 027 mm.