Michiro Komatsubara

Localized magnetic properties in grain‐oriented electrical steel measured by needle probe method

The accuracy of a needle probe method in measuring localized magnetic properties of grain-oriented electrical steel sheets was investigated and its application studied. The measuring error for the localized flux density was determined to be less than 1.7% for a load on the needle tip lighter than 300 g when the yoke structure was symmetrical with respect to the sheet plane. The average of localized iron losses measured with the combination of a needle probe and a Hall probe was in linear relation to the overall losses in the sheet. This method revealed that the localized magnetic properties vary markedly from location to location inside the sheet, and that localized iron loss depends on the localized flux density, domain wall spacing, and yaw angle of grain orientation.

Investigation of secondary recrystallization kinetics in grain-oriented electrical steel using the ultrasonic interferometry

Measurements of the growth rate for the individual secondary recrystallized Goss grain in Fe–3%Si containing AlN and MnSe as grain growth inhibitors were made by the ultrasonic interferometry. It was found that the growth rates in the rolling direction for secondary recrystallized grains varied from 0.3 to 0.6 mm/min, and that the growth rate in the rolling direction is 1.2–1.9 times higher than that of the cross-rolling direction. The set of results were explained in terms of the concept of the “growth advantage” which is defined as the fraction of high-energy grain boundaries having the misorientation angles between 20° and 45° with respect to the specific secondary recrystallized grain in the primary recrystallized grains.

Effect of crystal orientation on the iron loss and magnetostriction in domain refined highly grain oriented Si steel sheets

Iron loss and magnetostriction in domain refined highly grain oriented Si steel sheets were investigated. The degree of grain refining effect on iron loss has been found to be significantly influenced by crystal orientation. This phenomenon is explained by that reappearance of lancet domains during magnetization is strongly influenced by the tilt angle of [001] axis from sheet plane.

Effect of grain orientation on magnetic properties in secondary recrystallized 3% Si steel

Abstract The influence of continuous changes in crystal orientation inside grains of grain-oriented 3% Si steel sheets on their magnetic properties was investigated. It was demonstrated that the changing rate of β (tilt angle of [001] out of the sheet plane) inside a grain is determined by the the radius of curvature ( R ) in coils at the secondary recrystallization annealing, and that the average β over the whole sheet increases as R decreases. The increase in β strongly affected the domain structure and hence the magnetic properties. A minimum iron loss was obtained at the value of R at which the average β was about 2°, even when β changed inside grains.