Grain-oriented electrical steel sheet thermal strain domain control
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Solution Overview
Problem
Grain-oriented electrical steel sheets face a trade-off between achieving excellent noise characteristics and magnetic characteristics, with magnetic domain control often deteriorating noise characteristics and increasing iron loss.
Innovation Solution
Optimizing the combination of secondary recrystallization orientation control and magnetic domain control techniques, particularly by introducing thermal strain through laser irradiation with controlled line width and pitch, to refine magnetic domains without impairing magnetostriction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic domain control is applied to improve magnetic characteristics, then magnetic flux density is improved, but magnetostriction increases and noise characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the laser irradiation conditions (line width, pitch, and irradiation energy) to introduce thermal strain that refines magnetic domains while maintaining magnetostriction at acceptable levels. By optimizing these parameters, the patent achieves improved magnetic characteristics without excessive noise generation.
Solution Approach 2:
The patent applies local quality by introducing thermal strain locally through laser irradiation at specific locations and patterns on the steel sheet surface. This localized treatment refines magnetic domains in targeted areas while minimizing overall magnetostriction increase, thereby improving magnetic characteristics without uniformly deteriorating noise characteristics across the entire material.
2Loss of energy
If laser irradiation is used to control magnetic domains, then iron loss is reduced, but magnetostriction increases
Solution Approach 1:
The patent reduces iron loss while controlling magnetostriction by optimizing laser irradiation parameters including line width (10-300 μm), pitch (0.5-5.0 mm), and irradiation energy density. These parameter changes enable effective magnetic domain refinement for lower iron loss while keeping magnetostriction increase within acceptable ranges through precise control.
Solution Approach 2:
The patent applies partial action by using controlled laser irradiation with specific line widths and pitches that introduce just enough thermal strain to refine magnetic domains and reduce iron loss, without excessive strain that would cause significant magnetostriction increase. The irradiation conditions are optimized to achieve the minimum necessary effect for iron loss reduction.
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
This approach allows for improved magnetic characteristics without compromising noise characteristics, especially in thin materials, by managing surplus strain and orientation distribution angles to achieve low iron loss and magnetostriction.
Implementation Method 1
introducing thermal strain into a steel sheet by a laser beam or an electron beam
Implementation Method 2
final annealing is performed. Such final annealing causes secondary recrystallization, and the grain structure of the steel sheet is integrated in a {110} orientation
Implementation Method 3
MgO in the annealing separating agent reacts with the oxide films (Fe 2 SiO 4 and SiO 2) formed on the surface of the steel sheet during the decarburization annealing, whereby a glass coating is formed
Data Source
Figure 1~2B
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AI summary
A grain-oriented electrical steel sheet includes: a base steel sheet having a predetermined chemical composition; a glass coating provided on the surface of the base steel sheet; and a tension-applying insulation coating provided on the surface of the glass coating, in which linear thermal strains having a predetermined angle ϕ with respect to a transverse direction which is a direction orthogonal to a rolling direction are periodically formed on the surface of the tension-applying insulation coating at predetermined intervals along the rolling direction, a full width at half maximum F1 on the linear thermal strain and a full width at half maximum F2 at an intermediate position between the two linear thermal strains adjacent to each other satisfy 0.00 < (F1 - F2) / F2 ≤ 0.15, the width of the linear thermal strain is 10 µm or more and 300 µm or less, and in the base steel sheet, an orientation distribution angle γ around a rolling direction axis of secondary recrystallization grains, an orientation distribution angle α around an axis parallel to a normal direction, and an orientation distribution angle β around an axis perpendicular to each of the RD axis and the ND axis in units of ° satisfy 1.0 ≤ γ ≤ 8.0 and 0.0 ≤ (α2 + β2)0.5 ≤ 10.0.