Grain-Oriented Steel Sheet Iron Loss Reduction via Electron Beam Strain

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Solution Overview

Problem

Grain oriented electrical steel sheets with reduced iron loss through magnetic domain refinement techniques do not effectively improve iron loss properties when used in transformers, leading to poor building factors due to increased iron loss from magnetization rotation.

Innovation Solution

Introducing strain-imparted areas in a dotted line pattern with specific sizes and intervals to reduce iron loss in both the rolling direction and the direction orthogonal to the rolling direction, utilizing electron beam irradiation to optimize strain distribution and magnetic domain refinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If strain is imparted to reduce iron loss, then magnetic domain width is narrowed and iron loss decreases, but manufacturing complexity increases due to precise control requirements

Engineering Contradiction:
Improveiron lossVSAvoidmanufacturing process complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the strain-imparting process into discrete, patterned regions (dots or lines) rather than continuous treatment. This segmentation allows the use of focused energy sources like electron beams or lasers to create specific strain patterns at controlled intervals, simplifying the manufacturing process while achieving the desired magnetic domain refinement. The segmented approach enables precise control without requiring complex continuous processing systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional mechanical strain imparting methods with energy-based methods such as electron beam irradiation or laser heating. This substitution eliminates the need for complex mechanical rolling or pressing equipment, allowing strain to be imparted through localized thermal or electromagnetic effects that are easier to control and pattern. The energy-based approach enables precise spatial control of strain regions without complex mechanical tooling.

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

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 approach effectively reduces iron losses in both directions, resulting in a grain oriented electrical steel sheet with lower transformer iron loss, as demonstrated by experimental results showing decreased iron loss values under optimal strain conditions.

Implementation Method 1

an electron beam is irradiated according to variety of irradiation conditions

Methodology Applied
Scientific EffectElectron beam irradiation: Electron Beam

Implementation Method 2

a phenomenon called as magnetization rotation is known to occur. In magnetization rotation, the magnetization direction is oriented to a direction other than the rolling direction when magnetic excitation is provided

Methodology Applied
Scientific EffectMagnetization rotation: Magnetism

Implementation Method 3

a technique of irradiating a steel sheet as a finished product with laser to introduce high-dislocation density regions into a surface layer of the steel sheet

Methodology Applied
Scientific EffectLaser irradiation: Laser

Implementation Method 4

The increased tension in a direction of the dotted line causes a larger value of magnetic permeability in a direction orthogonal to the rolling direction by inverse magnetostriction effect

Methodology Applied
Scientific EffectInverse magnetostriction effect: Magnetostriction

Data Source

PatentEP2602347B1Grain-oriented magnetic steel sheet and process for producing same
Publication Date: 2019.02.20 JFE STEEL CORP
  • EP2602347B1 patent drawingFigure 1~2
  • EP2602347B1 patent drawingFigure 3~4
  • EP2602347B1 patent drawingFigure 5

AI summary

An object of the present invention is to propose a grain oriented electrical steel sheet capable of reducing iron loss when utilized in a iron core for a transformer and the like in a stacked state by means of magnetic domain refinement technique. Specifically, the grain oriented electrical steel sheet of the present invention has thermal strain introduced thereinto in a dotted-line arrangement in which strain-imparted areas have been lined in a direction that crosses the rolling direction of the steel sheet, wherein the strain-imparted areas introduced in the dotted-line arrangement have a size from 0.10 mm or more to 0.50 mm or less and an interval between the adjacent strain-imparted areas is from 0.10 mm or more to 0.60 mm or less.