Grain-Oriented Steel Sheet Orientation Control for Low-Field Magnetostriction
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Solution Overview
Problem
Conventional techniques for grain-oriented electrical steel sheets are insufficient in reducing magnetostriction, particularly in low magnetic fields, and face productivity issues and limitations in improving magnetic flux density.
Innovation Solution
The grain-oriented electrical steel sheet is produced with a chemical composition that includes Si, Nb, V, and other elements, and undergoes specific processing conditions to divide secondary recrystallized grains into small domains with varying deviation angles, inducing local and low-angle orientation changes to control magnetostriction and magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional techniques control deviation angles α, β, and γ to improve crystal orientation alignment, then magnetic flux density is improved, but magnetostriction in low magnetic fields cannot be sufficiently reduced
Solution Approach 1:
The patent applies local quality by creating non-uniform distribution of deviation angles within the steel sheet. Specifically, it controls that the standard deviation of deviation angle β in the width direction is 0.5° or more, and the average absolute value of deviation angle β is 2.0° or more, while maintaining overall alignment. This local variation in orientation quality reduces magnetostriction in low magnetic fields while preserving sufficient magnetic flux density.
2Manufacturing precision
If Nb and V are added to control deviation angles, then crystal orientation is improved, but magnetostriction reduction is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ranges of Nb (0.003-0.030 mass%) and V (0.003-0.030 mass%) along with Si (2.9-7.0 mass%). It also controls processing parameters including final annealing temperature (850-950°C) and the relationship between grain size and sheet thickness (0.05-0.20). These parameter optimizations enable sufficient magnetostriction reduction while maintaining crystal orientation.
3Manufacturing precision
If secondary recrystallized grain is allowed to grow excessively large to improve magnetic flux density, then magnetic flux density increases, but the effect is restricted due to coil curvature
Solution Approach 1:
The patent applies partial action by controlling grain size to an optimal range rather than allowing excessive growth. It specifies that the average grain size should be 0.05-0.20 times the sheet thickness, preventing grains from becoming excessively large while still achieving sufficient magnetic flux density improvement. This controlled partial growth avoids the negative effects of coil curvature.
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 effectively reduces magnetostriction in low magnetic fields and improves magnetic flux density by optimizing the crystal orientation and grain structure, leading to enhanced performance in transformer applications.
Implementation Method 1
the deviation angle β affects magnetostriction. Herein, the magnetostriction is a phenomenon in which a shape of magnetic material changes when magnetic field is applied.
Implementation Method 2
A grain oriented electrical steel sheet includes 7 mass% or less of Si and has a secondary recrystallized texture which aligns in { 110} orientation (Goss orientation).
Data Source
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AI summary
A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when (α1 β1 γ1) and (α2 β2 γ2) represent deviation angles of crystal orientations measured at two measurement points which are adjacent on the sheet surface and which have an interval of 1 mm, the boundary condition BA is defined as |β2 - β1| ≥ 0.5°, and the boundary condition BB is defined as [(α2 - α1)2 + (β2 - β1)2 + (γ2 - γ1)2]1/2 ≥ 2.0°, the boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included.