铝合金焊缝超声波检测工艺参数的选择

The Selection of Parameters of Transverse Wave Ultrasonic Testing for Aluminum Alloy Bus Weld

通过调整横波超声波检测工艺参数研究了其对6063铝合金焊缝检测效果的影响,分析了缺陷反射回波波幅随超声波参数的变化关系。试验结果表明,随频率增加,分辨率降低,发现细小缺陷的能力增加。仪器系统增益值随探头频率的增加遵循先降后增趋势,当频率为5 MHz时,仪器系统灵敏度最佳。晶片尺寸主要对近场区产生影响,当工件厚度小于15 mm时,晶片尺寸推荐选择为36 mm^2;缺陷回波的波幅与缺陷反射面的角度有关,当壁厚小于17 mm时,圆孔类缺陷回波波幅随K值增加而增大。铝合金焊缝横波斜探头超声波检测时工艺参数宜选用5 MHz、大K值、小晶片尺寸探头。

In this paper, various transverse wave ultrasonic testing （UT） parameters influencing the echo waveforms resulting of 6063 aluminum alloy weld were studied and analyzed. Experiments on the change of the inspection angle, frequency and diameter of ultrasonic transducer and echo waveform of defection with the parameters were conducted. The results showed that with increasing the frequency, ultrasonic testing sensitivity of the defects increased first but then decreased, and better sensitivity for the aluminum alloy bus weld testing by UT was obtained when the frequency was 5 MHz; Chip dimension was mainly influencing probes near field zone length. When the work piece thickness was less than 15 ram, it was recommended to use 36 mmz chip （with K being 2） for ultrasonic inspection for the aluminum alloy bus weld. Due to the fact that the echo waveform amplitudes of the defects were almost changed with the inspection angle of the probes, and when the work piece thickness was less than 17 mm, the amplitude curve of the defects increases with increasing the inspection angle for a circular hole. Better sensitivity for the aluminum alloy bus weld testing was obtained when the frequency of transverse wave probe is 5 MHz, the inspection angle was larger angle, and chip size was small.