因孔板流量计壳体焊缝结构特殊，其流量计管道短接外形和厚度尺寸变化等因素影响了无损检测方法的应用，为了解决壳体焊缝缺陷检出和厚度的测量问题，以及满足检测的要求，开展了时差衍射法超声检测、全聚焦相控阵超声检测和常规超声检测技术的检测试验，优化了超声检测方法，确保了检测的可靠性和准确性。通过检测数据分析，对不同超声检测方法的结构显示和相关焊缝缺陷显示特征进行了总结，为开展类似的检测活动提供参考。

Due to the special weld structure of orifice plate flowmeter shell, the short joint shape of flowmeter pipeline and the change of thickness and size, etc., the application of non-destructive testing technology is affected. In order to solve the problems of defect detection and thickness measurement of shell weld, and to meet the requirements of inspection, the application of time difference diffraction method, full focus phased array ultrasonic testing and conventional ultrasonic testing technology is studied. In order to ensure reliable and accurate detection, we should optimize the selection of ultrasonic detection methods. Through the analysis of test data, the structural display of different ultrasonic testing methods and the display characteristics of related weld defects are collected and summarized, which can provide reference for similar testing activities in the future.