Double-Oriented Electrical Steel Sheet for Bidirectional Magnetism
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Solution Overview
Problem
Existing grain-oriented electrical steel sheets primarily achieve secondary recrystallization in the Goss texture, making it challenging to develop cube and {100} fiber textures, which are essential for bidirectional magnetism with minimal magnetic deviation.
Innovation Solution
A double oriented electrical steel sheet is manufactured by controlling the reduction ratio in secondary cold rolling and the temperature increase rate during cold-rolled sheet annealing, thereby achieving secondary recrystallization of cube and {100} fiber textures using surface energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary recrystallization is used to achieve Goss texture with unidirectional magnetism, then magnetic properties in rolling direction are improved, but bidirectional magnetism cannot be achieved
Solution Approach 1:
The patent changes the texture orientation parameter from conventional Goss texture to cube and {100} fiber textures through controlled secondary recrystallization, enabling bidirectional magnetism while maintaining high magnetic properties in both rolling direction and perpendicular direction
Solution Approach 2:
The patent extends the magnetic property from one dimension (rolling direction only) to two dimensions (rolling direction and perpendicular direction) by achieving cube and {100} fiber textures that provide symmetry in both directions
2Manufacturing precision
If AlN precipitates are used for secondary recrystallization, then Goss texture development is promoted, but cube and {100} fiber textures cannot be formed
Solution Approach 1:
The patent changes the controlling parameter for secondary recrystallization from AlN precipitate dissolution to surface energy control, allowing cube and {100} fiber textures to form instead of the conventional Goss texture
Solution Approach 2:
The patent replaces the chemical mechanism (AlN precipitate dissolution) with a surface energy-based mechanism to drive secondary recrystallization, enabling formation of different texture types
3Manufacturing precision
If reduction ratio in secondary cold rolling is increased to control grain structure, then texture development is improved, but fine grain formation increases reducing magnetic properties
Solution Approach 1:
The patent optimizes the reduction ratio parameter in secondary cold rolling to a specific range that balances texture development with suppression of excessive fine grain formation, maintaining high magnetic properties
Solution Approach 2:
The patent creates different grain characteristics in different regions of the steel sheet through controlled reduction, allowing desired texture development while limiting fine grain formation that would harm magnetic properties
4Stability of the object's composition
If temperature increase rate during annealing is decreased to ensure uniform heating, then heating uniformity is improved, but fine grains are formed reducing magnetic performance
Solution Approach 1:
The patent sets the temperature increase rate to a specific range during annealing that prevents excessive fine grain formation while maintaining controlled and uniform heating, optimizing magnetic performance
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 resulting double oriented electrical steel sheet exhibits excellent bidirectional magnetic properties with high magnetic flux density and low iron loss, maintaining similar magnetic values in both the rolling direction and the direction perpendicular to it.
Implementation Method 1
a phenomenon called secondary recrystallization is essential. By using the secondary recrystallization phenomenon, grains in undesired directions may be consumed and grains in preferred directions may be grown
Implementation Method 2
annealing the secondary cold-rolled sheet. In the annealing of the secondary cold-rolled sheet, the annealing may be performed at a temperature of 1000 to 1200° C. for 6 to 60 hours
Data Source
AI summary
A double oriented electrical steel sheet according to an exemplary embodiment of the present disclosure contains, in wt %, at least 2.0% of Si, more than 0% and 0.02% or less of AI, 0.02-0.50% of Mn, more than 0% and 0.004% or less of C, and 0.0005-0.005% of S, with the remainder comprising Fe and inevitable impurities, wherein the area percentage of grains having a grain size of 2000 μm or less is 25% or less.