Microwave nondestructive testing method for internal defects of eddy-current-assisted welded metal plate

Abstract

The invention discloses a microwave nondestructive testing method for internal defects of an eddy-current-assisted welded metal plate, which comprises the following steps of: 1, selecting a low-frequency excitation coil, and selecting an adaptive excitation frequency; 2, designing a CSR detection unit; 3, a low-frequency excitation coil and a CSR detection unit are placed on the upper surface and the lower surface of the metal welding plate respectively; 4, adjusting the optimal vertical distance among the low-frequency excitation coil, the CSR detection unit and the welding metal plate at the defect-free position of the metal welding plate, so that the peak value of the resonant frequency of the CSR electromagnetic structure reaches the maximum; and 5, fixing the low-frequency excitation coil, moving the CSR detection unit on a plane parallel to the welded metal plate, and when obvious frequency offset of a resonance peak of a CSR electromagnetic structure is found, indicating that defects appear in the welded metal plate at the detection position. Through an eddy current auxiliary method, the CSR electromagnetic detection unit is used for sensing the difference of eddy current electromagnetic fields at different positions of the welded metal plate, and the deep defect structure of the welded metal plate is accurately positioned.

Description

technical field [0001] The invention belongs to the technical field of internal defect detection of welded metal plates, and in particular relates to a microwave nondestructive detection method for eddy current-assisted internal defects of welded metal plates. Background technique [0002] In many engineering fields such as transportation, aerospace, nuclear energy, electric power, etc., the sudden fracture of materials or parts is a common phenomenon in engineering. Fatigue fracture is the main failure mode of its parts, and the cracks caused by this form often have no obvious deformation and are difficult to detect, resulting in catastrophic accidents, resulting in huge economic losses and casualties. Therefore, in order to know cracks in advance and avoid unnecessary losses, effective and reliable nondestructive testing technology is essential. [0003] Microwave technology is widely used in the non-destructive testing of metal material defects due to its advantages of c...

AI Technical Summary

Problems solved by technology

The characteristics and methods of non-destructive testing of materials by microwave are determined by the interaction characteristics between materials. The depth of the electromagnetic field penetrating the metal surface into the interior is mainly determined by the electrical conductivity and magnetic permeability of the material. Due to the influence of skin depth , the electromagnetic field can only detect the defects on the surface, but it is difficult to detect the defect structure deep in the metal material

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