Research on deflection and focusing technology of pipeline annular ultrasonic phased array

Relevant theoretical knowledge of ultrasonic phased array and the propagation characteristics of a sound field are combined to establish the Rayleigh integral mathematical model of a phased array focused sound field and analyze the spatial distribution law. The deflection focusing delay rule of annular phased array is deduced by using the reverse phase matching method. The detection experiment is carried out with the carbon steel pipeline. The effects of the number of working array elements and deflection angle on the amplitude change of echo signal and the effect of defect detection are analyzed, and focusing conditions. Results show that the deflection focusing delay rule of an ultrasonic phased array can focus sound beams with different focal lengths and deflection angles. The number of working array elements is kept at 6–8, which can obtain good detection effect, and the deflection angle is within 10°, which can maintain good defect detection accuracy.