Method and apparatus for permanent magnetism destabilization nondestructive detection

Abstract

The invention discloses a permanent magnet magnetic disturbance non-destructive testing method and the device thereof. Wherein ,the method is that a permanent magnet body is arranged at the position 0 to 100mm away from the surface of a magnetic component to be detected so as to generate a mutual magnetic field; an enamelled copper wire or aluminum wire is encircled on the permanent magnet body, so that if the enamelled copper wire or aluminum wire captures the magnetic disturbance change fed from the permanent magnet body, the surface of the magnetic component to be detected has defects, otherwise do not. And the device comprises the permanent magnet body, the enamelled copper wire or aluminum wire, a signal collector and processor; the enamelled copper wire or aluminum wire is encircled on the permanent magnet body, the signal collector and processor is composed of a filter, an amplifier and an A / D converter which are connected in series. The detection sensitivity of the detection method of the invention has nothing to do with the trend of the defects on the surface of the magnetic component. The invention can detect all-directional defects and has the advantages that the detection method is easy to realize, the corresponding detection device is easy to operate and has simple structure, light weight, low cost and low energy consumption.

Description

technical field [0001] The invention relates to a non-destructive testing technology, in particular to a permanent magnet magnetic disturbance non-destructive testing method and device. Background technique [0002] At present, the methods for detecting discontinuity on the surface of magnetically conductive components mainly include magnetic particle testing, penetrant testing, ultrasonic testing, eddy current testing, and magnetic flux leakage testing. Magnetic particle testing uses residual magnetism to attract magnetic powder after magnetizing the magnetic conductive component to be tested, and then displays defects with traces of magnetic powder (GB / T 15822, non-destructive testing magnetic particle testing); penetrant testing uses penetrant to penetrate into the surface of the tested component and then observe its return Penetration to reveal defects (see GB / T 18851 Penetration testing for non-destructive testing). The above two detection methods are complicated in pr...

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Problems solved by technology

The above two detection methods are complicated in process, low in detection efficiency and easily affected by human operation

Ultrasonic detection requires a coupling medium, and the detection efficiency is low (see GB / T 5777-1996, Ultrasonic flaw detection inspection method for seamless steel pipes)

Eddy current testing uses eddy current as excitation to feed back detection information. The probe is designed with non-metallic material requirements for local components, which leads to poor wear resistance of the probe, and requires a signal generator as an excitation device (see GB / T7735-2004, steel pipe eddy current flaw detection method); magnetic flux leakage detection takes the leakage magnetic field at the defect as the detection object, and a magnetization circuit device and corresponding detection probes need to be formed, and different magnetization detection devices and scanning methods need to be adopted for defects in different directions, resulting in detection equipment Large volume, heavy weight, high cost (see GB / T 12606-1999, method for magnetic flux leakage flaw detection of steel pipes)

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