GB/T 12604.10-2023Non-destructive testing - Terminology - Part 10: Magnetic memory testing (English PDF)

1 Scope

This document defines the terminology used for the detection of magnetic memory in metals:

This document applies to metal magnetic memory testing:

2 Normative references

This document has no normative references:

3 Terms and Definitions

3:1 metal magnetic memory metalmagnetic memory; MMM The magnetic state of a ferromagnetic object after undergoing a change in the magnetic field and the accumulation of magneto-mechanical effects:

Note: For a given magnetic field (such as the earth's magnetic field), ferromagnetic objects formed during their manufacturing process or operation, due to various factors that affect the distribution of magnetic domains (3:21)

Environmental factors that change its residual magnetization (for example: temperature, mechanical load or microstructural change of the material):

[Source: GB/T 26641-2021, 3:1]

3:2 surface magnetic field magneticstrayfield; SF A magnetic field that leaves or enters the surface of a part and does not intentionally magnetize the part:

Note 1: A ferromagnetic material generates a magnetic field in its own volume and in the surrounding space: The field generated by the magnetization distribution of the material itself is called the surface magnetic field or the degenerate field within it:

magnetic field: The demagnetization field and the surface magnetic field are geometrically related, and when the magnetization is inhomogeneous or has a component normal to the outer or inner surface, the surface magnetization field will appear: High local variations in the surface magnetic field resemble flux leakage and are used to indicate inhomogeneity in material properties:

Note 2: Other terms used in the literature are, for example, spontaneous leakage magnetic field, residual magnetic field, surface magnetic field, leakage magnetic field, magnetic field density or surface field: When used for non-destructive testing

Surface magnetic field is the recommended term for passive magnetic field measurements, while flux leakage defines the magnetic flux amplified by external magnetization before or during inspection:

flux:

[Source: GB/T 26641-2021, 3:2]

3:3 surface magnetic field gradient strayfieldgradient

At the same probe position, the rate of change of the surface magnetic field (3:2) with the probe position and/or time:

[Source: GB/T 26641-2021, 3:6]

3:4 surface magnetic field vector stryfieldvector

The component of the surface magnetic field (3:2) of the object in the i direction (i=x, y, z) measured by the passive magnetic field sensing method:

[Source: GB/T 26641-2021, 3:4]

3:5

Deviation of SF (Surface Field) caused by high mechanical stress/strain gradients:

GB/T 13319 | GB/T 11349.1 | GB/T 12716 | GB/T 12604.14 | GB/T 12604.13 | GB/T 12604.6 | […]