Dependence of magnetic properties on crack size in steels

Author

Bi, Y. ; Jiles, D.C.

Author_Institution

Center for Nondestructive Evaluation, Iowa State Univ., Ames, IA, USA

Volume

34

Issue

4

fYear

1998

fDate

7/1/1998 12:00:00 AM

Firstpage

2021

Lastpage

2023

Abstract

A crack induces a local inhomogeneity in the magnetic flux path in a material and any change in crack area results in change in the distribution of magnetic flux. From the results of measurements on A533B steel and Cr-Mo steels, not only were the magnetic properties found to change with crack area, but also a linear relationship between measured remanence and crack area was observed. A model equation has been developed which shows agreement with the observed relationship. On the other hand, the coercivity and its relationship to crack area were found to depend upon the sensor position relative to the crack. 3D finite element analysis of the leakage field above a crack also showed the position dependence. Therefore, using the remanence measurement method described here fatigue damage and crack area in steel components can be evaluated nondestructively

Keywords

alloy steel; crack detection; fatigue cracks; ferromagnetic materials; finite element analysis; magnetic leakage; remanence; steel; 3D finite element analysis; A533B steel; Cr-Mo steels; coercivity; crack area; crack detection; crack size dependence; fatigue damage; leakage field; local inhomogeneity; magnetic flux path; magnetic properties; nondestructive evaluation; piping steel; pressure vessel steel; remanence; sensor position dependence; Area measurement; Coercive force; Equations; Finite element methods; Magnetic field measurement; Magnetic flux; Magnetic materials; Magnetic properties; Remanence; Steel;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.706778

Filename

706778