高频窄脉冲探头在从动盘超声检测中的应用

Application of high-frequency narrow-pulse probe in ultrasonic testing of clutch driven disc

在汽车离合器从动盘电子束焊缝自动超声检测中,从动盘厚度薄、焊缝窄、缺陷微小,检测时易出现上下界面反射波混叠,界面回波与缺陷回波难以识别等现象。为提高超声检测系统的分辨率、灵敏度和信噪比,讨论了探头参数对检测结果影响,确定探头参数,并研制出了专用于从动盘超声检测的高频窄脉冲探头。参照欧洲标准对专用探头进行频率特性测试,测试结果表明:专用探头的频率特性明显优于普通探头,更有利于提高检测系统的灵敏度、分辨率和信噪比。在实际生产中将专用探头应用于从动盘自动超声检测中,可有效检测出当量尺寸约为0.4 mm的微小缺陷,并满足检测要求。

During automatic ultrasonic testing of electron beam welding（EBW）,phenomenon of the reflected wave in the upper and lower interface of thin layer aliases and interface echo and the flaw echo are difficult to identify because of thin thickness,the narrow weld and small defects of clutch driven disc.In order to improve resolution,sensitivity,and signal to noise ratio of ultrasonic testing system,effects of probe parameters on test results is discussed,and probe parameters are determined,and special probe which is used for ultrasonic testing of clutch driven disc is developed.The ultrasonic probe is frequency characteristic tested referred to European standards,and test results show that frequency property of special probe is superior to conventional probe and it is helpful to improve sensitivity and resolution and signal to noise ratio of the detecting system.The special probe can effectively distinguish slight defects of the equivalent size of approximate 0.4 mm when it is applied to the driven disc automated ultrasonic testing and can reaches detecting requirements.