Grain-Oriented Electrical Steel Glass Film Adhesion via Spinel Interface
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Solution Overview
Problem
The adhesion of the glass film in grain oriented electrical steel sheets is not adequately improved by existing techniques, which affects the magnetic efficiency and insulation properties.
Innovation Solution
The grain oriented electrical steel sheet incorporates a specific chemical composition and a localized spinel (MgAl2O4) near the interface with the base steel sheet, as determined by glow discharge emission spectroscopy, to enhance adhesion, with the chemical composition including 0.010% or less of C, 2.5 to 4.0% of Si, and other elements, and the spinel localization satisfying specific intensity and time ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing techniques (adding rare earth elements, controlling void fraction, adjusting Si peak intensity) are used to improve glass film adhesion, then adhesion increases to some extent, but adhesion is not adequately improved and magnetic efficiency remains insufficient
Solution Approach 1:
The invention changes the chemical composition parameters of the base steel sheet, specifically controlling Si content at 2.5-4.0 mass%, Mn at 0.01-1.00 mass%, and adding specific amounts of Al (0.003-0.05 mass%), Mg (0.005-0.03 mass%), and O (0.005-0.04 mass%). These parameter changes optimize the formation of spinel and glass film, achieving adequate adhesion while maintaining magnetic efficiency.
Solution Approach 2:
The invention creates a composite structure at the interface between the base steel sheet and glass film by forming spinel (MgAl2O4) as an intermediate layer. This composite material approach, where spinel acts as a bonding phase between the steel sheet and the forsterite-based glass film, significantly improves adhesion while preserving magnetic properties.
2Strength
If Si content is increased to improve adhesion, then adhesion improves, but iron loss increases and magnetic efficiency deteriorates
Solution Approach 1:
The invention optimizes the Si content parameter within a specific range (2.5-4.0 mass%) rather than increasing it indiscriminately. This controlled parameter change, combined with adding Mn and controlling Al, Mg, and O content, achieves the desired adhesion improvement while keeping iron loss within acceptable limits (total loss ≤ 0.85 W/kg at 50 Hz, 1.5 T).
Solution Approach 2:
The invention applies local quality by concentrating Al, Mg, and O at the surface region of the base steel sheet to form spinel and glass film, while maintaining lower Si content in the bulk material. This localized enrichment of specific elements at the interface achieves adhesion improvement without compromising the overall magnetic efficiency of 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
This approach significantly improves the adhesion of the glass film to the base steel sheet, leading to enhanced magnetic efficiency and insulation properties, as confirmed by the improved remained fraction of the glass film after bending tests and acceptable iron loss values.
Implementation Method 1
when glow emission spectroscopic spectrums of Al and Si are measured by conducting a glow discharge emission spectroscopy from a surface of the glass film toward a depth direction
Data Source
AI summary
A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time TAlp at which Al shows a maximum emission intensity, an Al emission intensity F(TAlp) at the TAlp, a time TSip at which Si shows a maximum emission intensity, and an Al emission intensity F(TSip) at the TSip satisfy 0.05≤F(TSip)/F(TAlp)≤0.50 and 2.0≤(TAlp−Ts)/(TSip−Ts)≤5.0.