A non-destructive testing method for bulk defects based on the combination of pulsed eddy current and electromagnetic ultrasonic

Abstract

A non-destructive detection method for body defects based on the combination of pulsed eddy current and electromagnetic ultrasonic. Firstly, a permanent magnet is placed on the circular coil to make an electromagnetic ultrasonic / pulse eddy current composite probe. After the detected signal is filtered by the filter, the signal is collected by the data acquisition and analysis system, the detected signal is analyzed, and the composite signal is separated by combining the developed algorithm for separating and extracting the mixed detected signal based on strategies such as spectrum analysis and filtering. Extraction, so that the eddy current detection signal and the ultrasonic detection signal are respectively extracted from the mixed detection signal, and the defect information of different positions and types is detected through two different detection signals; the method of simultaneously separating and extracting the composite detection signal has high detection efficiency , Large detection range, compatible with surface defect and deep defect detection, wider thickness detection range, etc., has a wider application prospect.

Description

technical field [0001] The invention relates to the technical field of defect quantitative nondestructive testing based on electromagnetic and ultrasonic methods, in particular to a body defect nondestructive testing method based on the combination of pulsed eddy current and electromagnetic ultrasonic methods. Background technique [0002] With my country's vigorous investment in nuclear power in recent years, the number and installed capacity of nuclear power plants have continued to increase. However, the Fukushima nuclear power plant accident in 2011 once again proved that nuclear power safety needs to be paid close attention to 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 stress corrosion cracks due to the tensile stress state generated during production and use and the water env...

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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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