Annealing Separator Composition for Grain-Oriented Electrical Steel
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Solution Overview
Problem
Current annealing separating agents for oriented electrical steel sheets are expensive and have poor workability, limiting their application in mass production, and existing methods do not effectively reduce iron loss and improve magnetic characteristics.
Innovation Solution
The addition of γ-oxide aluminum to the annealing separating agent composition improves the close contacting property and magnetism of oriented electrical steel sheets by forming an Al—Mg composite phase and penetrating into the base texture, thereby reducing thermal expansion coefficients and enhancing elastic coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional annealing separating agents (kaolinite, halogen compounds, rare elements) are used to improve film tension and reduce iron loss, then magnetic characteristics are improved, but manufacturing cost increases significantly and workability deteriorates
Solution Approach 1:
The patent replaces expensive conventional additives (halogen compounds, rare elements like Ce, La, Pr, Nd, Sc, Y) with inexpensive γ-oxide aluminum powder that can be easily manufactured and applied. This additive achieves the desired film tension and magnetic characteristics without the high cost and poor workability of previous solutions.
Solution Approach 2:
The patent changes the chemical composition parameter of the annealing separating agent by introducing γ-oxide aluminum powder at specific concentrations (0.01-5 wt% based on steel sheet weight). This parameter change enables the formation of an Al-Mg-Si complex that provides both cost-effectiveness and improved magnetic characteristics.
2Reliability
If aluminum oxide (α-oxide aluminum) is added to the annealing separating agent to reduce thermal expansion coefficient, then film tension may be improved, but crystal phase change does not occur during annealing so iron loss reduction cannot be expected
Solution Approach 1:
The patent specifically uses γ-oxide aluminum powder instead of α-oxide aluminum because γ-oxide aluminum undergoes crystal phase change during the annealing process. This phase transition is critical for reducing thermal expansion coefficient and enabling iron loss reduction, whereas α-oxide aluminum remains stable and does not provide the desired effects.
Solution Approach 2:
The patent creates an Al-Mg-Si complex through the interaction of γ-oxide aluminum with magnesium oxide (from the annealing separating agent) and silicon dioxide (formed during primary recrystallization). This composite material structure provides both the necessary film tension and the thermal expansion coefficient reduction needed for iron loss reduction.
3Reliability
If aluminum hydroxide is added to form Al-Mg-Si complex to improve film tension, then magnetic characteristics are enhanced, but uniform powder particle size control is very difficult making it unsuitable for mass production
Solution Approach 1:
The patent replaces aluminum hydroxide with γ-oxide aluminum powder, which has the advantage of being easily manufactured with uniform particle size distribution. This makes the annealing separating agent suitable for mass production while still achieving the desired film tension and magnetic characteristics through Al-Mg-Si complex formation.
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 use of γ-oxide aluminum in the annealing separating agent composition leads to improved film tension, reduced iron loss, and enhanced magnetic characteristics of the oriented electrical steel sheets, making them suitable for high-efficiency transformer production.
Implementation Method 1
γ-oxide aluminum... penetrating into the base texture
Implementation Method 2
forming an Al—Mg composite phase
Implementation Method 3
a layer of forsterite (2MgO·SiO2) formed by a reaction of silicon dioxide (SiO2) generated in the process of a primary recrystallization annealing of an electrical steel sheet material and magnesium oxide (MgO) used as an annealing separating agent
Implementation Method 4
it is possible to bring about the effect of improving iron loss of the material by applying a tensile stress to the material due to a heat expansion coefficient difference between the material and the primary film
Data Source
AI summary
An oriented electrical steel sheet according to an embodiment of the present invention includes: a base texture; an AI permeation layer positioned on the base texture; and a film positioned on the AI permeation layer, wherein the AI permeation layer includes AI at 0.5 to 5 wt %, and the film includes an Al—Mg composite.