Magnetic Investigations of Steel Degradation Using a Magnetic Hysteresis Scaling Technique

Satoru Kobayashi,Kodai Miura,Seiki Takahashi,Yuki Narita

doi:10.3390/met8010002

Abstract

We report the results of magnetic measurements on austenitic stainless steels and duplex stainless steels using a magnetic hysteresis scaling technique. Unlike saturation hysteresis loops, this scaling technique, which uses a set of minor hysteresis loops, can be used in low measurement fields. We show that there is a universal scaling power law between minor-loop parameters, which is independent from the level of deformation. The behavior of a coefficient deduced from the scaling law was explained from the viewpoint of the morphology of a ferromagnetic phase.

Highlights

Studies on magnetic hysteresis scaling rules started about one century ago due to increasing demand for electrical steels; with regards to this, accurate knowledge of power losses at high flux densities was important
We found that hysteresis scaling relations exist between other hysteresis parameters and that the scaling exponent is almost independent of external and internal conditions
We have developed the scaling analysis method of magnetic minor hysteresis loops to characterize ferromagnetic α0 -martensite in 304 stainless steel subjected to plastic deformation [11,12] and/or cooling at 77 K

Summary

Introduction

Studies on magnetic hysteresis scaling rules started about one century ago due to increasing demand for electrical steels; with regards to this, accurate knowledge of power losses at high flux densities was important. It is known that a hysteresis loss of flux-density-magnetic-field (B-H) loops, or W F *, is related by power law to the maximum flux density (Ba *), with a scaling exponent of nF = 1.6 in the medium flux density range [1]. This is calculated using the following equation: n. Where the structure-sensitive magnetic property (W F 0 ) is a coefficient and Ba is a normalization constant This relationship (known as the Steinmetz law) has long been used, but its use is restricted mainly to the field of electricity. The magnetic method using magnetic hysteresis scaling is, a possible non-destructive evaluation (NDE) technique for materials degradation because of its sensitivity to lattice defects and its low measurement field

Results

Discussion

Conclusion