Grain-Oriented Steel Sheet Texture Optimization

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Solution Overview

Problem

Grain-oriented electrical steel sheets face limitations in improving core loss characteristics due to the difficulty in evaluating and optimizing the alignment of secondary recrystallized grains, particularly with the {110} orientation, as existing methods only consider deviation angles around the rolling surface normal and traverse directions, neglecting the impact of the deviation angle around the rolling direction.

Innovation Solution

Incorporating the evaluation of deviation angles α, β, and γ around the rolling surface normal, traverse, and rolling directions to assess the alignment of secondary recrystallized grains, with a focus on adjusting the deviation angle γ based on α and β to enhance core loss characteristics, and controlling the texture after primary recrystallization to achieve optimal orientation distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the {110} orientation alignment of secondary recrystallized grains is improved by reducing deviation angles α and β, then magnetic properties are enhanced, but core loss characteristic deteriorates when alignment becomes too high

Engineering Contradiction:
Improvemagnetic propertiesVSAvoidcore loss characteristic
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention changes the evaluation parameters from only α and β to include γ, and establishes a new quantitative relationship γ ≥ (α² + β²)^(1/2)/2. This parameter change allows optimization of the orientation distribution to achieve better core loss characteristics while maintaining magnetic properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention adds a new dimension (γ angle around rolling direction) to the traditional two-dimensional evaluation system (α and β angles). This three-dimensional orientation evaluation enables more comprehensive control of grain alignment and resolves the contradiction between magnetic properties and core loss.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If only deviation angles α and β around rolling surface normal and traverse directions are considered, then evaluation is simplified, but the impact of deviation angle γ around rolling direction is neglected

Engineering Contradiction:
Improveevaluation complexityVSAvoidorientation alignment evaluation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention transitions from a two-dimensional evaluation system (α, β) to a three-dimensional system by incorporating γ. This adds completeness to the orientation evaluation without significantly increasing complexity, as the new parameter γ can be measured using standard texture analysis methods.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention replaces qualitative assessment of orientation alignment with a quantitative mathematical relationship γ ≥ (α² + β²)^(1/2)/2. This substitution enables precise evaluation and optimization of orientation distribution based on measurable parameters.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the axes of individual crystal grains are made to match the rolling direction, then orientation alignment is improved, but it becomes difficult to achieve due to dispersion around ND and TD

Engineering Contradiction:
Improveorientation alignmentVSAvoidproduction difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the manufacturing target from achieving perfect alignment (α=0, β=0, γ=0) to achieving a quantitative relationship γ ≥ (α² + β²)^(1/2)/2. This parameter change makes the manufacturing target more realistic and achievable while still obtaining excellent magnetic properties and low core loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention accepts partial alignment (allowing dispersion around ND and TD) but compensates by controlling γ to satisfy the quantitative relationship. This partial action approach is more easily achieved in practice while still achieving the desired performance.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2039792B1Unidirectionally grain oriented electromagnetic steel sheet having excellent iron loss properties
Publication Date: 2017.07.05 NIPPON STEEL & SUMITOMO METAL CORP
  • EP2039792B1 patent drawingFigure 1~2
  • EP2039792B1 patent drawingFigure 3(a)~3(b)
  • EP2039792B1 patent drawingFigure 4~5

AI summary

Grain-oriented electrical steel sheet superior in core loss characteristic containing Si: 0.8 to 7 mass% and having a secondary recrystallized texture with a {110}<001> orientation as the main orientation, characterized in that average deviation angles α, β, and γ from the {110}<001> ideal orientation of the secondary recrystallized texture satisfy (α2+β2)1/2≤γ, where α: average deviation angle from {110}<001> ideal orientation around rolling surface normal direction (ND) of secondary recrystallized texture, β: average deviation angle from {110}<001> ideal orientation around traverse direction (TD) of secondary recrystallized texture, and γ: average deviation angle from {110}<001> ideal orientation around rolling direction (RD) of secondary recrystallized texture.