Grain-Oriented Electrical Steel Sheet Laser Strain Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing grain-oriented electrical steel sheets face challenges in reducing iron loss while maintaining excellent insulation properties and corrosion resistance, as thermal strain application methods like laser or electron beam irradiation often damage the insulating coating, requiring costly re-forming processes that can deteriorate magnetic properties.
Innovation Solution
A grain-oriented electrical steel sheet with controlled linear strain applied by high-energy beam irradiation, where the area ratio of irradiation marks and protrusions are optimized to minimize coating damage, allowing for reduced or no re-forming, maintaining low iron loss and excellent insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If thermal strain application is performed by laser beam irradiation or electron beam irradiation to reduce iron loss, then magnetic domain width is narrowed and iron loss is reduced, but the insulating coating is damaged causing insulation properties and corrosion resistance to worsen
Solution Approach 1:
The patent changes the parameters of thermal strain application by controlling laser beam power, irradiation speed, and irradiation pattern to achieve sufficient magnetic domain refinement while limiting coating damage. Specifically, the beam power is set to provide linear strain of 10^-3 to 10^-2, and the irradiation speed is controlled to maintain beam power density within specific ranges, thereby resolving the contradiction between iron loss reduction and coating preservation
Solution Approach 2:
The patent applies thermal strain partially by irradiating only specific regions of the steel sheet surface rather than the entire surface. This selective irradiation creates linear strain in targeted areas to reduce iron loss while leaving other areas with intact coating, thus achieving the beneficial effect without completely damaging the insulation properties
2Reliability
If re-forming is performed to restore insulation properties after coating damage, then insulation properties are improved, but manufacturing cost increases and magnetic properties deteriorate
Solution Approach 1:
The patent applies preliminary protective measures by optimizing the thermal strain application parameters before coating damage occurs. By controlling laser beam power and irradiation conditions to stay within specific ranges, the coating is protected from severe damage in the first place, eliminating or reducing the need for re-forming operations and their associated costs and magnetic property deterioration
3Reliability
If beam power is suppressed or focus is blurred to reduce thermal strain amount and suppress coating damage, then insulation properties are maintained, but iron loss reduction amount decreases
Solution Approach 1:
The patent optimizes multiple parameters simultaneously including laser beam power, irradiation speed, beam diameter, and irradiation pattern to achieve the precise linear strain range of 10^-3 to 10^-2. This multi-parameter optimization allows sufficient iron loss reduction while maintaining coating integrity, resolving the contradiction between maintaining insulation properties and achieving iron loss reduction
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 achieves reduced iron loss and preserved insulation properties without the need for extensive re-forming, enhancing the steel sheet's performance as an iron core in transformers while maintaining cost-effectiveness and magnetic property integrity.
Implementation Method 1
it is important to highly accord secondary recrystallized grains of a steel sheet with (110)[001] orientation... a technique has been developed to introduce non-uniformity into a surface of a steel sheet by physical means to subdivide the width of a magnetic domain to reduce iron loss... Thermal strain application-based magnetic domain refinement techniques such as laser beam irradiation and electron beam irradiation
Implementation Method 2
JP S57-2252 B2 proposes a technique of irradiating a steel sheet as a finished product with a laser to introduce high-dislocation density regions into a surface layer of the steel sheet, thereby narrowing magnetic domain widths and reducing iron loss
Implementation Method 3
JP H6-072266 B2 proposes a technique of controlling the magnetic domain width by electron beam irradiation
Data Source
AI summary
A grain-oriented electrical steel sheet, on which magnetic domain refining treatment by strain application has been performed, has an insulating coating with excellent insulation properties and corrosion resistance. In a grain-oriented electrical steel sheet, linear strain having been applied thereto by irradiation with a high-energy beam, the linear strain extending in a direction that intersects a rolling direction of the steel sheet, an area ratio of irradiation marks within an irradiation region of the high-energy beam is 2% or more and 20% or less, an area ratio of protrusions with a diameter of 1.5 μm or more within a surrounding portion of the irradiation mark is 60% or less, and an area ratio of exposed portions of steel substrate in the irradiation mark is 90% or less.