Grain-Oriented Electrical Steel Strain Pattern for Lower Iron Loss
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Solution Overview
Problem
Existing grain-oriented electrical steel sheets face challenges in achieving low iron loss and low noise characteristics due to increased hysteresis loss and magnetostriction from magnetic domain width refinement techniques, despite reductions in eddy-current loss.
Innovation Solution
Introduce linear strains on the surface of the steel sheet with a periodically varying width and direction, shifting the period of width change between adjacent strains to suppress hysteresis loss while maintaining magnetic domain refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If closure domain regions with periodically changing width are formed, then magnetostriction is reduced, but the complexity of manufacturing increases
Solution Approach 1:
The patent applies periodic action by forming closure domain regions with periodically changing width in the rolling direction. The periodic variation (with specific parameters: Wmax/Wmin ratio of 1.2-2.2, average width 80-250 μm) creates a rhythmic pattern that effectively reduces magnetostriction while maintaining manufacturability through standardized periodic structures.
2Productivity
If laser irradiation is applied to reduce iron loss, then productivity is maintained, but noise characteristics deteriorate due to increased magnetostriction
Solution Approach 1:
The patent applies parameter changes by carefully controlling the parameters of strain regions (width ratio 1.2-8.0, average width 30 μm or more, depth 32 μm or more) and closure domain regions (periodic width variation with Wmax/Wmin of 1.2-2.2, average width 80-250 μm). These parameter optimizations reduce magnetostriction and noise while maintaining the productivity benefits of laser irradiation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves lower iron loss by reducing eddy-current loss and suppressing hysteresis loss without hindering magnetic domain wall movement, resulting in improved magnetic characteristics.
Implementation Method 1
A technique for performing laser irradiation on a steel sheet surface has been proposed as a method for reducing the iron loss. In this technique, strain is introduced to the surface by the laser irradiation, and the 180° magnetic domain width is refined.
Implementation Method 2
the width periodically increases and decreases in the extending direction of the linear strain in a period of 200 to 400 μm; among the linear strains, between the adjacent linear strains, the period in which the width changes is shifted by 0.4 to 0.6 periods
Implementation Method 3
As a result, the eddy-current loss that is a part of the iron loss can be reduced
Data Source
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AI summary
The grain-oriented electrical steel sheet includes a plurality of linear strains introduced in a surface and extending in a direction of 60 to 120° with respect to a longitudinal direction, in which the linear strains adjacent to each other have an interval of 2 to 10 mm in the longitudinal direction; the linear strain has a width in a direction perpendicular to an extending direction of the linear strain, and the width periodically increases and decreases in the extending direction of the linear strain in a period of 200 to 400 µm; among the linear strains, between the adjacent linear strains, the period in which the width changes is shifted by 0.4 to 0.6 periods in the extending direction of the linear strain; the ratio of the maximum of the width with respect to the minimum of the width is 1.2 to 8.0; and the minimum of the width is 30 µm or more.