DEVICE FOR DETERMINING DEGREE OF INHOMOGENEITY OF STRUCTURAL STATE OF MAGNETIC METALS BY EDDY CURRENT METHOD Russian patent published in 2020 - IPC G01N27/72 

FIELD: metallurgy.

SUBSTANCE: invention relates to methods of nondestructive testing and can be used for assessment of degree of inhomogeneity of surface layers of magnetic metals arising during quenching, tempering and action of liquid or gaseous aggressive media. Proposed device comprises generator of harmonic oscillations, current of which circulates through two exciting coils, one of which is located above control object, and another one - at distance from control object. Feedback frequency is used to set the generator frequency at which maximum sensitivity to change of structural properties takes place. Voltage on the measuring coil, the radius of which is determined to be significantly greater than the approximate depth of the layer, within which the structural state changes, when measured for an object with a constant structural state, is stored in a memory and control unit.

EFFECT: quantitative determination of the relative magnetic permeability and degree of non-uniformity of the structural state of the object.

1 cl, 8 dwg