Research On Ultrasonic Detection Method Based On The Pipeline Coating Defect

Pipelines as essential tool of transporting, once that been damaged which will bringsignificant influence for national economy and natural environment as well. The pipelineanticorrosion layer as the first barrier to protect the pipeline, it is very important for detectionand evaluation of anticorrosion coating defects. Nowadays, several of measurement techniquesexist for pipelines anticorrosion coating, among of them, ultrasonic testing as anon-destructive testing means which are used commonly by researchers. Ultrasonic wavecanpropagate energy in two-layered medium less than that in single layered medium, by using thecharacteristic, this paper proposes that using the method of ultrasonic to test breakage, peeland other defects of pipeline anticorrosion layer.This paper studies the principle and characteristics of ultrasonic testing technology, othermethods of pipeline coating defect detection in engineering inspection, and to study thecurrent research level of the testing technology of anticorrosion coating. Study on thecharacteristics of ultrasonic propagation in single layer and double layer medium, includingwaveform classification, ultrasonic wave propagation velocity, sonic pressure and acousticimpedance, attenuation of ultrasonic and other characteristics. Analysis ultrasonic wavedisplacement, stress and strain in the doubling plate as well. By using the finite elementsimulation software COMSOL Multiphysics to analysis the state of ultrasonic propagation insingle layer steel plate, iron plate which covered with intact organic glass, steel plate whichcoated with the outworn organic glass, to analysis ultrasonic wave propagation characteristicswhich been changed after adding anticorrosion layer. The experimental platform has been setup, According to simulation results verified, to determine the ultrasonic based pipelineanticorrosion layer testing method can verify the theory and simulation. Analyze the results ofsimulation and experiment, comprise the change between the experimental data and theultrasonic propagation characteristics, to propose a suitable method for testing of anticorrosioncoating defects.According to the results of simulation and experiment, covered with anticorrosion layercan be influence on ultrasonic propagation in steel. In double layered medium, Ultrasonicwave can come up refraction, reverberation and wave-type conversion when the propagation meets the interface between medium. Therefore, more acoustic energy can be consumed, andthen ultrasonic wave propagation velocity can be diminution, amplitude be lessened, energy bereduced. While the anticorrosion layer wear out, which means the cover area of anticorrosionlayer decrease, ultrasonic wave propagation velocity and amplitude larger than that in steellayer covered with intact anticorrosion layer, however smaller than that in single steel layer.This conclusion provides a theoretical basis for testing of coating defects by ultrasonictechnology in engineering practice.