Structured Electrical Steel Sheet for Eddy Current Loss Reduction
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Solution Overview
Problem
Anomalous eddy current losses in electrical steel sheets produced by non-rolled methods, such as printing and tape casting, are not effectively reduced by conventional surface structuring techniques like scoring, etching, or laser treatment, as these methods often damage the crystal structure and are not applicable during the production process.
Innovation Solution
The method involves structuring the surface of a green body before thermal treatment, using additive manufacturing, structured substrates, or local electromagnetic radiation to create elevations or grooves that remain intact during thermal processing, thereby reducing anomalous eddy current losses in electrical steel sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional surface structuring techniques like scoring, etching, or laser treatment are used on electrical steel sheets produced by non-rolled methods, then surface structuring is achieved, but the crystal structure is damaged and the methods are not applicable during production
Solution Approach 1:
The surface structuring is performed on the green body before thermal treatment, rather than on the finished electrical steel sheet. This preliminary action allows the structure to be created when the material is still in a formable state, avoiding damage to the crystal structure during subsequent thermal processing
Solution Approach 2:
The patent changes the physical state parameter of the steel from solid finished sheet to green body (unsintered compacted powder), enabling surface structuring at a stage where the material can be shaped without damaging its internal structure
2Ease of manufacture
If surface structuring is performed after thermal treatment, then the electrical steel sheet is ready for use, but the surface structure is damaged or not preserved
Solution Approach 1:
The surface structuring is performed before thermal treatment rather than after, ensuring the structure is created while the material is still in a formable state and will be preserved through the thermal processing
Solution Approach 2:
The conventional sequence is inverted: instead of producing the steel sheet first and then structuring the surface, the patent structures the surface of the green body first and then performs thermal treatment to produce the finished sheet, thereby preserving the surface structure
3Loss of energy
If conventional surface structuring methods are used on finished electrical steel sheets, then surface grooves are created for domain refinement, but the methods cause damage and are not suitable for production integration
Solution Approach 1:
The surface structuring is performed as a preliminary step during production (on the green body before thermal treatment) rather than as a post-processing step on finished sheets, integrating it into the manufacturing flow and avoiding damage to the finished product
Solution Approach 2:
The patent changes the state of the material from finished solid sheet to green body, enabling surface structuring to be performed as part of the production process rather than as a separate post-processing operation
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 allows for significant reduction in anomalous eddy current losses with minimal additional effort, as the surface structuring is preserved through thermal treatment, enhancing the domain refinement and microstructure of the electrical steel sheets.
Implementation Method 1
thermally treating the green body (10)
Implementation Method 2
the green body (10) is locally partially heated by means of electromagnetic radiation
Data Source
AI summary
Various embodiments include a method for producing an electrical steel sheet comprising the following steps: placing a green body comprising a first material on a substrate; structuring a surface of the green body; and thermally treating the green body.