活塞杆摩擦焊接头的超声检测及缺陷二维重构

针对活塞杆摩擦焊接头的未熔合缺陷,采用超声无损检测方法对部件接头进行检测并提取了含噪声的超声回波信号,利用小波降噪法对含噪声缺陷信号进行了降噪处理,通过多位置、多点检测的方法对未熔合缺陷进行了二维轮廓重构.结果表明:1) 通过优化小波阈值降噪算法的参数提高了回波信号的信噪比,可以提升检测的有效性与准确性;能实现对缺陷信号的降噪并保证信号的完整性;2) 对检测数据进行理论计算确定了缺陷的多位置边缘点,通过缺陷边缘点的拟合,实现了未熔合缺陷的二维轮廓重构,重构结果与破坏性检验结果基本吻合.

Ultrasonic testing of friction welded piston rod joints and two-dimensional reconstruction of defect contour

For the incomplete fusion defect of the friction welded joint of the piston rod, the ultrasonic non-destructive testing method was used to testing the weld joint of the piston rod and then the ultrasonic echo signal containing noise was extracted. The wavelet noise reduction method was used to filter and reduce the defect signal containing noise.The two-dimensional contour reconstruction of the incomplete fusion defect is carried out by the method of analyzing multi-position and multi-point ultrasonic echo signal. The result shows that: 1) By optimizing the parameters of the wavelet threshold noise reduction algorithm, the signal-to-noise ratio of the ultrasonic echo signal can be improved, and the effectiveness and accuracy of the detection result can be improved. Also it can realize the noise reduction of the defect signal and ensure the integrity of the signal;2) Inspection data was theoretically calculatedto determine the edge points of the defect. Through fitting the edge points of the multi-position defect, the two-dimensional contour reconstruction of the incomplete fusion defect is realized, and the reconstruction result is basically consistent with the destructive inspection result.