分析了动车组构架部分需检测的结构特殊的焊缝，介绍了在动车组新制和检修构架中使用超声相控阵检测焊缝中裂纹、未熔合等缺陷的应用案例，详细叙述了检测方案的确定过程以及探头与楔块、发射晶片、角度范围、步进偏置等相关工艺参数的选定方法，且进行了方案可行性验证试验。结果表明，超声相控阵检测技术能实现对动车组构架异型焊缝的检测。

This paper analyzes the weld seam of the frame part of the EMU which needs to be inspected but has a special structure, and introduces an application case of ultrasonic phased array in detecting weld crack and non-fusion defects in the process of new system and overhaul frame of EMU. It describes in detail the determination process of the scheme, the selection method of the relevant technological parameters, such as the probe and the wedge, the emitting wafer, the angle range, the step bias, and the process of feasibility verification of the scheme. The results show that ultrasonic phased array detection technology can be used to detect abnormal weld of the frame of EMU.