弧形触头的超声无损检测方法

Ultrasonic Nondestructive Testing Method for Arc Surface Electric Contact

针对弧形触点的钎焊质量检测问题,首先建立了弧形触点的超声C扫描图像模型。通过分析发现,由于弧形触点特殊结构的影响,在对缺陷回波采样过程中叠加的表面回波分量在C扫描图像中形成了不均匀分布的图像背景,这是影响C扫描图像质量的主要原因。基于上述分析,首先对弧形触点进行超声C扫描成像,然后采用二次多项式拟合了图像的不均匀背景,并根据拟合结果校正了C扫描图像。试验结果表明,校正图像不仅去除了不均匀背景的影响,而且更加真实、准确地反映了钎焊界面的缺陷分布情况。

Aimed to the testing problem of brazing quality of arc surface electric contact, its ultrasonic C-scan image model was built firstly. It is found that the superposition of surface echo on the defect echo during the sampling process, which is caused by the special structure of arc surface contact, results in the non-uniform background in C-scan image. That is the key reason influencing the C-scan image quality. Based on the analysis, the arc surface contact was C-scanned firstly, and then a second-order polynomial was used to fit the non-uniform background. The C-scan image was corrected by removing the fitted background. The experiment shows that the detrimental effect of non-uniform background is eliminated after correction and the corrected image re-visualizes the defects in the brazing interface more accurately.