Non-oriented electrical steel sheet uniform crystal orientation

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Solution Overview

Problem

Non-oriented electrical steel sheets struggle to achieve high magnetic flux density without incurring significant iron loss, due to limitations in controlling crystal orientation and chemical composition across the sheet thickness.

Innovation Solution

A non-oriented electrical steel sheet with a specific chemical composition and manufacturing process that maintains an appropriate relationship between chemical composition and crystal orientation, including controlled columnar grain ratio, average grain size, and rolling reduction, to enhance magnetic characteristics uniformly across the sheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional techniques are used to improve magnetic flux density, then magnetic flux density increases, but iron loss deteriorates

Engineering Contradiction:
Improvemagnetic flux densityVSAvoidiron loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The invention changes chemical composition parameters (C: 0.0030% or less, Si: 2.00% or less, Al: 1.00% or less, Mn: 0.10% to 2.00%, S: 0.0030% or less) and processing parameters (columnar grain ratio: 80% or more, average grain size: 0.10 mm or more, rolling reduction: 90% or less) to achieve both high magnetic flux density and low iron loss simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention controls crystal orientation locally throughout the sheet thickness by maintaining specific chemical composition and processing conditions, ensuring uniform {100} orientation from surface to center, which optimizes magnetic properties while controlling iron loss

Inventive Principle:
Principle #3Local quality

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 enables the attainment of high magnetic flux density with reduced iron loss by ensuring uniform crystal orientation and composition, improving magnetic performance without compromising on iron loss.

Implementation Method 1

cold rolling a steel strip obtained by the hot rolling; a rolling reduction in the cold rolling is 90% or less

Methodology Applied
Scientific EffectCold rolling: Plasticity

Implementation Method 2

final annealing a cold rolled steel sheet obtained by the cold rolling

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentUS11469018B2Non-oriented electrical steel sheet and method for manufacturing non-oriented electrical steel sheet
Publication Date: 2022.10.11 NIPPON STEEL CORPORATION

AI summary

A non-oriented electrical steel sheet according to one embodiment of the invention has a chemical composition represented by C: 0.0030% or less, Si: 2.00% or less, Al: 1.00% or less, Mn: 0.10% to 2.00%, S: 0.0030% or less, one or more selected from the group consisting of Mg, Ca, Sr, Ba, Nd, Pr, La, Ce, Zn, and Cd: greater than 0.0100% and not greater than 0.0250% in total, a parameter Q represented by Q=[Si]+2×[Al]−[Mn]: 2.00 or less; Sn: 0.00% to 0.40%, Cu: 0.00% to 1.00%, and a remainder: Fe and impurities, and a parameter R represented by R=(I100+I310+I411+I521)/(I111+I211+I332+I221) is 0.80 or greater.