带不锈钢堆焊层的主管道焊缝全聚焦超声检测

Total focus ultrasonic testing of main pipe weld with stainless steel surfacing layer

针对带不锈钢堆焊层的主管道焊缝在进行超声检测时,存在结构噪声干扰严重的问题,开展了全聚焦(TFM)超声成像试验研究。以堆焊层内部深度为65 mm,直径为2 mm的侧钻孔为例,当所用阵元数从16增加到64时,其TFM图像信噪比提高了5.3 dB,阵列性能指数降低了35%。在此基础上,进一步引入相位相干成像(PCI)法,对TFM图像进行加权处理。与原始TFM图像相比,PCI法能有效改善图像的信噪比和分辨力。对于64阵元得到的图像,信噪比提高了13.19 dB,阵列性能指数降低了约65%。

To solve the problem that structural noise interferes the defect identification of main pipe weld with stainless steel surfacing layer by ultrasonic testing, the total focusing method(TFM) is carried out by experiments in this paper. Taking the side-drilled hole with 2 mm diameter and 65 mm internal depth in the surfacing layer as an example, the TFM imaging results show that the signal-to-noise ratio increases by 5.3 dB and the array performance indicator decreases by 35% when the number of array elements are increased from 16 to 64. On this basis, phase coherence imaging(PCI) is introduced to weight the TFM image. PCI method can effectively improve the signal-to-noise ratio and image resolution. Compared with the original TFM images, signal-to-noise ratio increases by 13.19 dB and array performance indicator decreases by 65% for the image obtained by 64 elements.