Grain-Oriented Steel Sheet Magnetic Domain Refinement
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Solution Overview
Problem
Conventional methods for reducing iron loss in grain-oriented electrical steel sheets, such as those used in transformers, often result in increased hysteresis loss and noise due to excessive hardening of the steel sheet, which is caused by rapid thermal deformation and high irradiation energy during magnetic domain refinement processes like heat beam, light beam, or particle beam irradiation.
Innovation Solution
Reducing irradiation energy and extending irradiation time, using charged particles smaller than Fe, and scanning the beam at a slower rate to minimize hardening and improve magnetic domain refinement, thereby reducing both hysteresis and eddy current losses, and minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rapid thermal deformation is applied for magnetic domain refinement, then eddy current loss decreases, but noise increases due to hardening
Solution Approach 1:
The patent transforms the thermal deformation parameter from rapid to slow heating rate (0.1°C/s to 10°C/s). This gradual heating approach refines magnetic domains effectively while minimizing hardening-induced noise, achieving low noise levels of 45 dBA or lower
2Loss of energy
If high irradiation energy is used for magnetic domain refinement, then eddy current loss is reduced, but the steel sheet hardens excessively
Solution Approach 1:
The patent changes the irradiation energy parameter from high to low levels and extends the treatment time. This parameter transformation achieves magnetic domain refinement without excessive hardening, maintaining appropriate ductility while reducing eddy current loss
Solution Approach 2:
The patent uses extended periodic irradiation at low energy levels rather than a single high-energy application. This approach allows gradual magnetic domain refinement without creating excessive hardening in the steel sheet
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
Achieves a grain-oriented electrical steel sheet with reduced iron loss (less than 0.80 W/kg) and noise (45 dBA or lower) by minimizing hardening and optimizing magnetic domain refinement, enhancing energy efficiency and transformer performance.
Implementation Method 1
rapid thermal deformation of the steel sheet caused near the irradiated portion
Implementation Method 2
magnetic domain refinement which reduces eddy current loss
Implementation Method 3
exhibit an increase in hardness of the steel sheet surface due to work hardening by 5 % or more
Data Source
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AI summary
Disclosed is a grain-oriented electrical steel sheet exhibiting reduced iron loss and reduced noise. The present invention provides an electrical steel sheet that has magnetic domains refined by regions with a high lattice defect density being locally formed on the surface of or within the steel sheet, in which the regions with a high lattice defect density has a hardness, as measured by a micro Vickers hardness meter, equal to or lower than that of other regions.