Pipeline defect detection method and device based on electromagnetic ultrasonic longitudinal guided waves

Abstract

The invention discloses a pipeline defect detection method based on electromagnetic ultrasonic longitudinal guided waves. The method comprises the following steps: arranging a plurality of annular magnets coaxial with a pipeline, so as to generate a radial static magnetic field on the surface of the pipeline; coaxially sleeving two sides of each annular magnet array with solenoid coils, so as to generate circumferential inducing vortex in the to-be-detected pipeline; and stimulating longitudinal-mode guided waves under the combined action of the circumferential inducing vortex and the radial static magnetic field, wherein when encountering a defect, the longitudinal-mode guided waves are reflected, and reflection echoes cause change of sensing voltage of a sensing coil when passing through a sensing coil, so as to judge that whether the defect exists in the pipeline or not. The invention further discloses a detection device and a sensor for detecting the pipeline by virtue of the device and the method. According to the method, the radial magnetic fields at the edges of the magnet arrays are adequately utilized, and the uniform radial magnetic field does not need to be generated, so that the complexity of the sensor is reduced; meanwhile, a single longitudinal-mode guided wave signal can be obtained, so that the defect signal analysis difficulty is reduced, and the detection process is rapid and efficient.

Description

technical field [0001] The invention relates to the technical field of ultrasonic nondestructive testing, in particular to a pipeline defect testing method and device. Background technique [0002] With the rapid development of petroleum, chemical, energy and other industries, industrial pipelines are playing an increasingly important role in industrial production and operation. In the process of production and operation, industrial pipelines often have failures such as corrosion, perforation or wall thickness reduction due to high temperature, high pressure, erosion, corrosive media, etc., resulting in leakage or explosion accidents. In order to avoid the actual effect of industrial pipelines from causing harm to industrial production and social security, it is necessary to carry out regular inspection and maintenance on industrial pipelines. [0003] Ultrasonic guided wave testing technology has the advantage of being able to detect the distance at one end with a single p...

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Problems solved by technology

[0009] However, the electromagnetic ultrasonic longitudinal guided wave sensor uses Lorentz forces in two directions to excite the longitudinal mode guided wave. On the one hand, it requires a large number of magnets and solenoid coils, and the sensor structure is complicated; The combined action of the Lorentz force will lead to the impurity of the excited ultrasonic guided wave mode, resulting in multiple modes of defect echo signals, which will eventually increase the difficulty of defect signal analysis

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