一种复杂结构件圆柱面扩散焊缝阵列超声检测方法

A superalloy disc component of aeroengine is fabricated by welding between disc and blade ring. Because of the complexity of component structure, the single element ultrasonic testing method has met same problems such as low detection efficiency and low signal-to-noise ratio of defect signals. In order to improve the detection ability of this kind of structure, the automatic ultrasonic array detection method of the cylindrical weld is studied. Firstly, the effect of relative positions of the planar defect and the acoustic source on the defect refection acoustic pressure is analyzed. The wave conversion conditions of different reflected acoustic waves are analyzed and the pitch and catch method based on dual ultrasonic array transducers is put forward. Then, according to the structural characteristics of the specimen, an acoustic beam transmitting-receiving method and a full coverage inspection scheme for the cylindrical weld are designed. A response simulation model of the ultrasonic array is established based on the finite-difference time-domain (FDTD) method and the detection parameters are designed and optimized. Finally, the detection experiment is carried out on the actual specimen with prefabricated defects, and the results show that the proposed dual ultrasonic array transducer detection method can effectively detect the prefabricated defects with diameter of 2 mm in the cylindrical weld area.