A non-destructive testing method for small-diameter pipes based on the principle of electromagnetic ultrasonic phased array focusing

Abstract

The invention discloses a small-diameter pipe nondestructive detecting method based on an electromagnetic ultrasonic phased array focusing principle. The small-diameter pipe nondestructive detecting method is implemented by a solenoid bias magnetic field generating unit which is arranged outside a small-diameter pipe and is coaxial with the small-diameter pipe, and an electromagnetic ultrasonic probe which is formed by electromagnetic ultrasonic exciting coil units coaxially arranged in the small-diameter pipe and array detection coil units arranged uniformly along the circumferential direction of the pipe. The small-diameter pipe nondestructive detecting method comprises the following steps: firstly, generating a high bias magnetic field along the axial direction of the small-diameter pipe by an electrified solenoid; setting the exciting time of each exciting coil in the electromagnetic ultrasonic exciting coil units according to a focusing law, and exciting the coils sequentially by the electromagnetic ultrasonic device so as to generate ultrasonic waves; meanwhile, detecting voltage signals caused by the ultrasonic waves by the array detection coil units circumferentially arranged on the pipe cross section on which focusing points are located; and detecting the small-diameter pipe comprehensively and rapidly with the assistance of axial machinery scanning. The method provided by the invention has the advantages of high detection rate, high detection speed, high efficiency and the like, and can be widely applied to nondestructive detection on the interiors of small-diameter pipes with complex outer shapes and on debonding defects of a multi-layer pipe HIP (Hot isostatic press) welding interface.

Description

technical field [0001] The invention relates to the technical field of non-destructive testing of small-diameter tubes based on the principle of electromagnetic ultrasonic phased array focusing, in particular to a nondestructive testing method for small-diameter tubes based on the principle of electromagnetic ultrasonic phased array focusing. Background technique [0002] With the advancement of the International Thermonuclear Experimental Reactor (ITER) program, the safety and integrity assessment of the tokamak fusion device has attracted more and more attention. As an important part of the tokamak device, the divertor plays the role of removing impurities and heat, ensuring the normal operation of the device. The divertor uses a large number of tungsten block-copper tube heat exchange components with HIP welding interface, and the inner diameter of the heat exchange tube is small (usually about 10 mm). In order to realize the effective welding of the square tungsten bloc...

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Problems solved by technology

[0006] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an electromagnetic ultrasonic nondestructive testing method for small-diameter tubes based on the principle of phased array focusing. The method of the present invention has the advantages of high detection rate, fast detection speed, and high efficiency. It can be widely used in non-destructive testing of debonding defects inside small-diameter pipes with complex external shapes and HIP welding interfaces of multi-layer pipes

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