MDL-based nondestructive testing device for local stress distribution of ferromagnetic material

Abstract

The invention discloses an MDL-based nondestructive testing device for local stress distribution of a ferromagnetic material. The detection device comprises an MDL with a uniform cross section, an excitation coil, a detection coil, a permanent magnet, a supporting piece and an ultrasonic echo detector; the MDL is arranged horizontally over the detected ferromagnetic material; the excitation coil and the detection coil are wound around the MDL, and distance between the excitation coil and the detection coil is avoid interference between excitation signals of the excitation coil and detection signals of the detection coil; the permanent magnet is fixed on the upper surface of the MDL; the supporting piece is arranged between the MDL and the detected ferromagnetic material to support the MDLand the permanent magnet; and the ultrasonic echo detector is attached to the detected ferromagnetic material via a preset through hole in the supporting piece so as to detect the thickness of the detected ferromagnetic material. Thus, rapid detection of local or continuous area(s) can be realized, and high precision and high sensitivity are ensured.

Description

technical field [0001] The invention belongs to the field of nondestructive detection of local stress distribution of ferromagnetic materials, in particular to a nondestructive detection device for local stress distribution of ferromagnetic materials based on magnetostrictive delay strips (MDL). Background technique [0002] Stress detection is very important in the field of modern industrial production and processing, especially for the local stress detection technology on the surface and inside of materials, which has an important impact and engineering significance on the service life of products and material reliability detection. The existence of residual stress will seriously affect the strength and related properties of the workpiece. It is mainly due to the internal stress remaining inside the material after machining and thermal processing and maintaining internal balance. If it is not treated, in the use of the material, due to uneven Operations such as heat treatm...

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Problems solved by technology

[0004] However, due to the detection principle of various devices used in the current magnetic measurement method, that is, after scanning a whole material area, the average profit level under a single probe is obtained according to the calculation of the calculation software, and then the stress of the entire area is generated. Horizontal curve, so the detection results obtained are the results after averaging and simulation, and the material has size restrictions, the detection speed is slow, and the actual detection accuracy is not high enough

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