纯铜板大面积搭接叠加电阻钎焊工艺及缺陷检测

Resistance brazing of large-area overlapping pure copper plate

对不同叠加面积的纯铜板进行搭接电阻钎焊工艺试验和钎缝的超声波探伤、金相测试研究。结果表明:施加电极压力大小和施加压力的均匀性是钎合率达到要求和焊接质量稳定的关键因素,选用合适的电极压力可以使不同叠加面积的纯铜板电阻钎焊获得理想的钎合率。平均宽度小于78 μm的钎缝内部以局部焊缝间隙小形成的未熔合缺陷为主,平均宽度大于78 μm的钎缝内部以钎料未填满形成的"疏松"和圆形孔洞缺陷为主,超声波探伤与金相测试的钎合率大小相一致,可以采用超声波探伤对大面积叠加电阻钎焊的钎合率进行有效的检测。

In this paper,the resistance brazing of pure copper plates with different overlapping areas made under different electrode pressures was studied by ultrasonic testing and metallographic testing.The magnitude and the uniformity of the applied electrode pressure are the key factors for the brazing rate to meet the requirements and the welding quality to be stable.Under proper electrode pressure,the resistance brazing of pure copper plates with different overlapping areas can obtain ideal brazing rate.The results of ultrasonic inspection and metallographic examination of the brazing seam show that the unfused defects with small local weld gap are the main defects in the brazing seam whose average width is less than 78μm,while in the brazed seam whose average width is over 78μm,the main defects are looseness and round holes formed by the unfilled solder.The ultrasonic flaw detection is consistent with the metallographic testing,so the ultrasonic flaw detection can be used to effectively detect the brazing rate of large-area overlapping resistance brazing.