Method for ultrasonically detecting weld quality of main loop pipeline of nuclear power plant by phased array

The invention discloses a method for ultrasonically detecting the weld quality of a main loop pipeline of a nuclear power plant by a phased array and belongs to the technical field of ultrasonic non-destructive detection and evaluation. According to the method, a phased array ultrasonic test system composed of a Dynaray Lite ultrasonic phased array tester, an integrated UltraVision3.2R9 phased array operation system, a scanning device and a calibration block is adopted. Aiming at the main pipeline having a thickness of 66-99 mm, a proper area array probe is selected, and a focusing principle parameter, an ultrasonic parameter and a mechanical parameter are matched, so as to perform layered detection on a weld of the main pipeline and the peripheral region. Layered permeation in the existing means for detecting the main pipeline is only capable of detecting the surface open defects of the weld; radiographic detection is incapable of quantifying defect depths and insensitive to area defects such as cracks and incomplete fusion; and the conventional ultrasonic detection technology has the defects of being low in detection efficiency, high in cost, low in imaging capacity and the like. The method disclosed by the invention overcomes the defects is good in quantifying accuracy and high in efficiency in field detection, and has great economic benefits and social benefits.