近场对相控阵超声TCG校准的影响

Influence of near-field on the TCG calibration of phased array ultrasonic testing

在国内外焊接接头相控阵超声检测标准中,通常要求或推荐使用时间校正增益(TCG)对不同深度反射体灵敏度进行补偿,以保证检测结果的准确性。与此同时,在相应的相控阵超声验收标准中,多采用波幅和长度的验收方式,因此TCG校准的准确性是相控阵超声检测应用的基础,其重要性不言而喻。文章通过计算近场深度并进行对比试验,分析了近场对于相控阵超声TCG校准的影响。该试验结果可为相控阵超声检测时探头与楔块的选择以及参数的设置提供参考。

In international and domestic standards of phased array ultrasonic testing for welded joints, Time-corrected gain(TCG) calibration are usually required or recommended to be used to compensate the sensitivity of reflectors at different depths, so as to ensure the accuracy of detection result. At the same time, in the corresponding phased array ultrasonic acceptance standard, the acceptance method based on the amplitude and length is mostly adopted, so the accuracy of TCG calibration is the basis of phased array ultrasonic detection application, its importance is self-evident. In this paper, the influence of near field on phased array ultrasonic TCG calibration is analyzed through calculation and comparative test. The research results can provide reference for the selection of probe and wedge and the setting of parameters in phased array ultrasonic testing.