Magnetic circuit focusing sharing type multi-channel online detection system and method

Abstract

The invention relates to a magnetic circuit sharing type multichannel online detection system which comprises a sensor array composed of a plurality of probes, a tomography detection module and a defect signal alarm module, the probes are magnetic circuit focusing sharing type probes and comprise alternating current excitation coils, combined magnet units, three-axis force sensors and accelerometers, the combined magnet units are connected with the three-axis force sensors, and the three-axis force sensors are connected with the accelerometer. The Halbach array permanent magnet is used for providing a focusing magnetic field and sequentially comprises a Halbach array permanent magnet and a core body from outside to inside, and the core body is composed of a cylindrical permanent magnet and an iron-cobalt alloy magnetic core upper part and a cylindrical permanent magnet and an iron-cobalt alloy magnetic core lower part. According to the system and the method, electromagnetic ultrasonic and Lorentz force eddy current detection technologies are combined, magnetic circuit focusing and sharing are realized through probe design, the magnetic field intensity is multiplied, the detection sensitivity is greatly improved, the detection rate of near-surface small defects is obviously improved, the detection depth of electromagnetic ultrasonic is greatly enhanced, and the detection precision is greatly improved. The defects that all defects cannot be detected at a time and the sensitivity is not high in the prior art are overcome, so that full-coverage detection of near-surface defects and defects within the thick wall range is achieved, and meanwhile the conductivity of the plate can be obtained through Lorentz force detection.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic non-destructive testing, and in particular relates to a magnetic circuit focusing aluminum plate testing technology. Background technique [0002] The manufacturing process of aluminum sheet is usually carried out at speeds up to 20–30m / s, higher speeds such as 40–60m / s can be observed during wire drawing. For the on-line inspection technology of aluminum sheet manufacturing quality, there are mainly Electromagnetic Acoustic Transducer (EMAT for short) and Lorentzforce eddy current testing technology (LET for short). Document 1 designed an eddy current detection probe, which can detect defects within 3mm of the surface at most, but cannot detect deep defects due to the skin effect. According to the semi-analytic method of electromagnetic field, Document 2 confirms that theoretically the surface of the workpiece to be tested is also a part of the electromagnetic ultrasonic probe, and the b...

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Problems solved by technology

[0008] Therefore, electromagnetic ultrasonic testing technology is suitable for obtaining materials in the thick-walled range, but it has a surface blind area in the detection; Lorentz force eddy current testing technology is suitable for crack detection and conductivity evaluation on the surface and near the surface of moving components. But it cannot cover defect detection in the whole wall thickness range

That is to say, the above two existing detection technologies cannot combine detection sensitivity and full detection coverage in the entire wall thickness range

However, the existing composite method does not efficiently solve the problem of defect detection within the entire wall thickness range of the aluminum plate. The single method in the combination does not achieve the highest detection sensitivity of each. In order to meet the detection requirements of one method, the detection capability of another method must be improved. Making constraints reduces the detection effect of the entire composite method to a certain extent, and the overall function has not been fully exploited

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