Nondestructive detection method for early damage of ferromagnetic material

Abstract

The invention discloses a nondestructive detection method for early damage of a ferromagnetic material. The method comprises the following steps of: detecting a leakage magnetic field on the surface of a ferromagnetic structure by using a magnetic sensor to obtain a tangential leakage magnetic amplitude and a normal leakage magnetic amplitude of the detected surface, and storing the amplitudes in an intelligent magnetic memory through a coaxial cable; calculating a leakage magnetic tangential gradient value and a leakage magnetic normal gradient value of the detected surface according to the tangential leakage magnetic amplitude and the normal leakage magnetic amplitude of the detected surface; and determining a damage part and a damage degree according to the acquired leakage magnetic tangential gradient value and leakage magnetic normal gradient value of the detected surface. The method is nondestructive detection means for on-line monitoring of the early damage degree of the ferromagnetic material massively used in the industrial application field.

Description

technical field [0001] The invention relates to a magnetic non-destructive detection method for early damage of ferromagnetic materials, which belongs to the field of measurement technology. Background technique [0002] Due to the initial prestress during assembly and the accumulated residual stress during long-term use of metal components, material performance degradation and local structural damage are caused, and accidents that eventually cause the overall system to fail suddenly occur from time to time. In the petrochemical industry, more than 70% of sudden accidents are caused by various initial defects related to prestress in metal components and fatigue damage developed from them. Although theoretically speaking, the fatigue failure process of metal materials generally includes three basic stages: the initial damage accumulation stage, the macro crack formation stage and the crack growth stage, but its actual service life mainly depends on the first stage, which acco...

AI Technical Summary

Problems solved by technology

However, the two basic criteria proposed by Russian scholars (the tangential component H P (x) reaches the maximum value, the normal direction component H P (y) peak-to-peak variation) is only applicable to macroscopic defects, not applicable to early damage detection of materials

In addition, there are many parameters affecting the early damage of materials, including physical damage parameters and geometric damage parameters. How to effectively invert the multi-parameters based on the magnetic flux leakage signal is still lack of relevant research

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