Electrical Steel Sheet Texture Control for Stable Iron Loss After Shearing

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Solution Overview

Problem

Non-oriented electrical steel sheets experience fluctuations in magnetic characteristics, particularly iron loss, after shearing due to rough cross-sections and fracture behaviors during processing, which affect the crystal structure and orientation.

Innovation Solution

A non-oriented electrical steel sheet with specific chemical compositions and controlled crystal orientations, where {100} orientated grains are preferentially grown through strain-induced boundary migration, and the areas and area ratios of {100} and {111} orientated grains are optimized on the steel sheet surface to maintain excellent magnetic characteristics post-shearing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If strain-induced boundary migration is utilized to control texture, then magnetic characteristics are improved, but characteristics fluctuate after shearing

Engineering Contradiction:
Improvemagnetic characteristicsVSAvoidcharacteristic stability after shearing
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the crystallographic orientation parameters by controlling the area ratio of {100} orientated grains to be 0.75 or more, which fundamentally alters the texture characteristics to improve magnetic properties while enhancing stability after shearing operations

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary texture control during manufacturing by utilizing strain-induced boundary migration to establish the desired {100} orientation distribution before shearing, thereby pre-preventing characteristic fluctuations that would otherwise occur during subsequent processing

Inventive Principle:
Principle #10Preliminary action

2Reliability

If {100} orientation is controlled to improve magnetic flux density, then magnetic characteristics are improved, but iron loss increases due to fracture behaviors during shearing

Engineering Contradiction:
Improvemagnetic flux densityVSAvoidiron loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention optimizes the area ratio parameter of {100} orientated grains to be 0.75 or more, which simultaneously improves magnetic flux density while reducing iron loss by creating a more stable texture that resists fracture-induced degradation during shearing operations

Inventive Principle:
Principle #35Parameter changes

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 ensures that the non-oriented electrical steel sheet maintains excellent magnetic characteristics, including low iron loss, by controlling the crystal structure and grain sizes, thereby stabilizing the magnetic properties even after shearing.

Implementation Method 1

it was recognized that, in non-oriented electrical steel sheets for which strain-induced boundary migration has been utilized

Methodology Applied
Scientific EffectStrain-induced boundary migration:

Implementation Method 2

performing a heat treatment on the non-oriented electrical steel sheet at a temperature of 700° C. to 950° C. for 1 second to 100 seconds

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentUS20240158896A1Non-oriented electrical steel sheet and method for manufacturing same
Publication Date: 2024.05.16 NIPPON STEEL CORPORATION

AI summary

This non-oriented electrical steel sheet has a predetermined chemical composition, when EBSD observation is performed on a surface parallel to a steel sheet surface, in a case where a total area is indicated by Stot, an area of {100} orientated grains is indicated by S100, an area of orientated grains in which a Taylor factor M becomes more than 2.8 is indicated by Styl, a total area of orientated grains in which the Taylor factor M becomes 2.8 or less is indicated by Stra, an average KAM value of the {100} orientated grains is indicated by K100, and an average KAM value of the orientated grains in which the Taylor factor M becomes more than 2.8 is indicated by Ktyl, 0.20≤Styl/Stot≤0.85, 0.05≤S100/Stot≤0.80, S100/Stot≥0.5, and K100/Ktyl≤0.990 are satisfied.