Pulsed eddy current and electromagnetic ultrasonic composite based nondestructive body defect testing method

Abstract

The invention discloses a pulsed eddy current and electromagnetic ultrasonic composite based nondestructive body defect detecting method. Firstly, a permanent magnet is put on a round coil, an electromagnetic ultrasonic / pulsed eddy current composite probe is manufactured, a pulsed eddy current device is used for performing pulsed excitation on the probe, detecting signals are separated through a duplexer, filtered by a filter, acquired by a data acquisition system and analyzed, a separation and extraction algorithm is performed on mixed detecting signals in combination of developed strategies based on spectral analysis, filtering and the like, and composite signals are separated and extracted, so that eddy current detecting signals and ultrasonic detecting signals are extracted respectively from the mixed detecting signals and are used for detecting different types of defect information in different positions. The method for simultaneously separating and extracting the composite detecting signals has the advantages of high detection efficiency, wide detection range, compatibility for detection of both surface defects and deep defects, wider thickness detecting range and the like, and has a wider application prospect.

Description

Technical field [0001] The invention relates to the technical field of defect quantitative non-destructive testing based on electromagnetic and ultrasonic methods, in particular to a non-destructive testing method for body defects based on the combination of pulsed eddy current and electromagnetic ultrasonic. Background technique [0002] As my country has invested heavily in nuclear power in recent years, the number of nuclear power plants and installed capacity have continued to increase. However, the Fukushima nuclear power plant accident that occurred in 2011 once again proved that nuclear power safety issues need to be highly concerned by people from all walks of life. In the safety management of nuclear power plants, regular non-destructive testing is an important means to ensure the safe operation of the system. Some key components of nuclear power plants are prone to initiation of stress corrosion cracks due to the tensile stress state generated during production and use...

AI Technical Summary

Problems solved by technology

However, due to the near-surface blind area of ​​electromagnetic ultrasonic testing, that is, when the defect is close to the surface (1mm-2mm), the echo signal will almost overlap with the excitation signal and it is difficult to distinguish

[0004] The pulsed eddy current testing method has high accuracy for near-surface defects, but due to the limitation of skin depth, it cannot accurately measure deeper places

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