Grain Oriented Electrical Steel Sheet Laser Domain Refinement
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Solution Overview
Problem
Grain oriented electrical steel sheets struggle to achieve satisfactory iron loss properties due to limitations in magnetic domain refinement techniques, particularly in reducing iron loss while maintaining effective magnetic properties.
Innovation Solution
A grain oriented electrical steel sheet with a forsterite coating and tension coating, subjected to laser irradiation, where the chromium content is suppressed to 0.1 mass % or less, and the coating weight and thickness are optimized to enhance tensile strength and magnetic domain refinement, achieving a magnetic flux density of 1.91 T or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the width of magnetic domain is reduced by laser irradiation to reduce iron loss, then iron loss properties are improved, but the complexity of manufacturing process increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling laser irradiation parameters (power, speed, pattern) and coating parameters (forsterite coating weight, anchor portion thickness) to achieve magnetic domain refinement. By optimizing these parameters, the patent reduces iron loss while managing manufacturing complexity through systematic parameter optimization rather than process redesign.
2Loss of energy
If Cr content is suppressed to 0.1 mass % or less to improve magnetic properties, then iron loss properties are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent addresses this contradiction by changing the approach from strict Cr content suppression to optimizing multiple parameters simultaneously. By controlling forsterite coating weight (≥3.0 g/m²), anchor portion thickness (≤1.5 μm), and laser irradiation parameters, the patent achieves low iron loss properties without requiring extremely precise Cr content control, thus reducing manufacturing precision requirements.
3Strength
If forsterite coating weight is increased to enhance tensile strength, then coating strength is improved, but laser irradiation effectiveness is reduced
Solution Approach 1:
The patent applies local quality by differentiating the forsterite coating into two functional zones: an anchor portion with thickness ≤1.5 μm that allows effective laser irradiation and magnetic domain refinement, and a surface portion with total coating weight ≥3.0 g/m² that provides sufficient tensile strength. This local differentiation resolves the contradiction between coating strength and laser effectiveness.
4Loss of energy
If magnetic domain width is reduced to reduce iron loss, then iron loss properties are improved, but manufacturing process complexity increases
Solution Approach 1:
The patent replaces complex mechanical or chemical methods for magnetic domain control with laser irradiation. By using laser energy to induce thermal effects and stress changes in the steel sheet, the patent achieves magnetic domain refinement more simply than traditional mechanical rolling or chemical treatment methods, thus reducing overall manufacturing process complexity while improving iron loss properties.
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 solution effectively reduces iron loss by controlling magnetic domain structures through laser irradiation, improving the iron-loss reducing effect compared to prior art, while maintaining high magnetic properties.
Implementation Method 1
irradiating a steel sheet as a finished product with a laser to introduce high-dislocation density regions into a surface layer of the steel sheet
Implementation Method 2
narrowing magnetic domain widths and reducing iron loss of the steel sheet
Implementation Method 3
subjecting the steel sheet to decarburizing annealing; then coating a surface of the steel sheet with annealing separator mainly composed of MgO
Implementation Method 4
subjecting the steel sheet to decarburizing annealing
Implementation Method 5
subjecting the steel sheet thus coated to final annealing
Data Source
AI summary
A grain oriented electrical steel sheet (1) suppresses the content of Cr in the grain oriented electrical steel sheet to 0.1 mass % or less; (2) sets the coating weight of a forsterite coating, in terms of basis weight of oxygen therein, to at least 3.0 g/m2 and thickness of an anchor portion as a lower portion of forsterite coating to 1.5 μm or less; and (3) controls setting the magnitude of deflection of a test specimen having length: 280 mm to at least 10mm when the forsterite coating is provided on only one surface thereof and at least 20 mm when forsterite coating and the tension coating are provided on the surface.