Nondestructive detection system and method for pulsed magnetic flux leakage defects and stresses

Abstract

The invention relates to a nondestructive detection system and method for pulsed magnetic flux leakage defects and stresses, belonging to the field of nondestructive detection. The system comprises a signal generator, a power amplifier, an excitation coil, a Hall sensor, a signal amplification circuit, a data acquisition card and a computer. In the invention, on the basis of pulsed magnetic flux leakage detection, signal processing is performed on a ferromagnetic material in segments according to a transient ascent phase of pulse excitation and a continuous high level phase after the rise, and the separation of stress signals and defect signals is realized; as signal characteristic extraction and data fusion are performed respectively, the simultaneous on-line detection of defects, stresses and microstructure states of a surface and a subsurface of the ferromagnetic material is realized, and the judgment of hidden defects and the estimation of unformed defects of the ferromagnetic material are realized. The nondestructive detection system can work reliably for a long term, has the advantages of high sensitivity, high antijamming capability and high response speed, and is free fromthe influences of a medium such as oil / water pollution and the like.

Description

Technical field [0001] The invention relates to the field of non-destructive testing, in particular to a non-destructive testing system and a non-destructive testing method that realizes the separation of defects and stress signals according to pulse excitation signals and realizes the defects and stresses of ferromagnetic materials. Background technique [0002] Magnetic flux leakage detection technology is an important method for non-destructive evaluation of ferromagnetic materials such as pipelines. With the increase of pipelines and the growth of pipeline age, pipeline leakage and pipeline incidents caused by corrosion, abrasion, accidental damage, etc. occur frequently and become more serious. Due to the danger and pollution of the transported medium, accidents will cause huge Loss of life and property and environmental pollution. Pipeline online inspection technology is currently the most widely used and most effective pipeline inspection method. It uses the detection pri...

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Problems solved by technology

[0004] In view of the existing method of steady-state analysis of the test signal using the magnetic flux leakage detection technology, some important information of the signal in the time domain is ignored, and only the defect of the pipeline can be detected, the stress of the pipeline cannot be detected, and the life of the pipeline cannot be evaluated. The applicant has carried out improved research to provide a non-destructive testing system and non-destructive testing method for pulsed magnetic flux leakage defects and stresses that use pulsed magnetic flux leakage technology for nondestructive testing to achieve quantitative and life assessment of pipeline defects

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