Grain-Oriented Steel Sheet Magnetic Domain Refining Deflection Control
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Solution Overview
Problem
Conventional grain-oriented electrical steel sheets subjected to magnetic domain refining face challenges in achieving consistent iron loss properties in transformers due to uneven deflection and stress distribution during core production, leading to variations in transformer performance despite equivalent steel sheet properties.
Innovation Solution
The grain-oriented electrical steel sheet is refined by introducing linear strains in a direction intersecting the rolling direction with controlled intervals, optimizing the shape to minimize deflection when placed on a flat surface, with a specific ratio of strain interval to height difference, thereby reducing iron loss in transformers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If strains are introduced into one side of the steel sheet for magnetic domain refining, then magnetic domain width is narrowed and iron loss is reduced, but deflection occurs where the strain-introduced surface becomes the inner side
Solution Approach 1:
The patent applies preliminary anti-action by introducing strains on both sides of the steel sheet in opposite directions before the deflection problem occurs. This pre-applied counteracting strain prevents the net deflection that would result from single-sided strain introduction, while still achieving magnetic domain refinement. The strains are introduced simultaneously or sequentially on both surfaces to create balanced internal stresses that refine magnetic domains without causing macroscopic bending.
Solution Approach 2:
The patent applies local quality by introducing strains only in specific linear regions on both sides of the steel sheet rather than uniformly across the entire surface. The strain introduction is localized to create high-dislocation density regions that subdivide magnetic domains, while maintaining different properties in different areas of the sheet. This selective local treatment achieves magnetic domain refinement without uniform deflection.
2Loss of energy
If strains are introduced to refine magnetic domains, then iron loss properties are improved, but stress distribution becomes uneven during core production
Solution Approach 1:
The patent applies local quality by introducing strains in specific linear patterns on both sides of the steel sheet, creating localized high-dislocation density regions. This localized strain distribution refines magnetic domains in critical areas while maintaining more uniform overall stress characteristics. The alternating pattern of strained and non-strained regions creates a balanced stress field that prevents concentration in single areas during core production.
Solution Approach 2:
The patent applies the counterweight principle by introducing equal and opposite strains on both sides of the steel sheet. These counterbalancing strains create a system where internal stresses are distributed more uniformly throughout the sheet thickness. The opposing strains act as counterweights to each other, preventing the development of uneven stress fields that would occur with single-sided treatment during subsequent core production and assembly.
3Loss of energy
If beam power, scanning rate, or irradiation interval is increased to enhance strain introduction, then magnetic domain refining effect is improved, but deflection and stress concentration increase
Solution Approach 1:
The patent applies partial action by introducing strains on both sides of the steel sheet, where the combined effect of partial strains from each side achieves the desired magnetic domain refinement without the excessive deflection that would result from high-intensity single-sided treatment. The strain intensity on each individual side can be optimized to be moderate, while the cumulative effect provides sufficient domain refinement.
Solution Approach 2:
The patent uses counterweight by applying equal and opposite strains on both surfaces of the steel sheet. This counterbalancing approach allows each side to contribute to magnetic domain refinement through strain introduction, while the opposing nature of the strains prevents net deflection. The counteracting forces enable higher strain intensities to be applied without the detrimental deflection effects.
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 ensures reduced iron loss in transformers by controlling the shape and stress distribution of the steel sheets, enhancing magnetic domain refining effects and maintaining magnetic properties without excessive stress concentration.
Implementation Method 1
irradiating a surface of a finished product steel sheet with a laser beam or an electron beam
Implementation Method 2
irradiating a surface of a finished product steel sheet with a laser beam or an electron beam
Implementation Method 3
the strains cause local deformation in steel sheets
Data Source
AI summary
A grain-oriented electrical steel sheet subjected to magnetic domain refining by linearly introducing strains in a direction intersecting a rolling direction of the steel sheet repeatedly with intervals in the rolling direction, wherein if a repeating interval of the strains in the rolling direction is d (mm) and, when the steel sheet is placed on a flat surface, a mean value of difference between a height from the flat surface in linear strain-introduced areas of a steel sheet surface and a height from the flat surface in intermediate points between adjacent linear strain-introduced areas is h (mm), then the ratio h/d of the h to the d is 0.0025 or more and 0.015 or less.