Method for discriminating stress concentration of ferromagnetic materials by utilizing detection of metal magnetic memory

Abstract

The invention provides a method for discriminating stress concentration of ferromagnetic materials by utilizing detection of metal magnetic memory, which belongs to the field of metal nondestructive detection. The method adopts a stress concentration magnetic detector at least comprising two scan channels, and specifically comprises the following: step 1, preparing for pre-detection; step 2, using the stress concentration magnetic detector to measure normal magnetic field intensity Hy(x) and tangential magnetic field intensity Hx(x) on the surface of a detected ferromagnetic material along a length direction; step 3, performing arithmetic mean on the acquired normal magnetic field intensity Hy(x) and tangential magnetic field intensity Hx(x) of two or more channels respectively; Step 4, performing smoothed data filtering on data after arithmetic mean; step 5, performing wavelet filtering on the data after smoothed data filtering; step 6, calculating normal magnetic field gradient, tangential magnetic field gradient and peak-to-peak value according to the data after wavelet filtering calculation; and step 7, discriminating stress concentration.

Description

technical field [0001] The invention belongs to the field of metal non-destructive testing, and in particular relates to a method for detecting stress concentration of ferromagnetic materials by using metal magnetic memory. Background technique [0002] In modern industry, a large number of ferromagnetic metal components, especially boiler pressure vessels, pipes, bridges, railways, steam turbine blades, rotors and important welded parts, etc., will bear fatigue loads to varying degrees during use, resulting in fatigue cracks. Frequency damage failure occurs. Since fatigue cracks mostly originate in stress concentration areas caused by microscopic defects on the surface or near the surface, it is of great significance to effectively implement stress detection on the surface and near the surface of components for the safe use of ferromagnetic material components. Currently, non-destructive testing methods are commonly used to search for defects such as cracks, pores, and inc...

AI Technical Summary

Problems solved by technology

[0003] However, there is noise in the metal magnetic memory detection signal at present, and the signal must be processed, and whether it is a stress concentration area is judged by whether a single normal magnetic field strength has a zero point, which is easy to cause missed diagnosis or misdiagnosis

Images