Electrical Steel Oxide Layer for Coating Adhesion and Low Iron Loss
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Solution Overview
Problem
The grain oriented electrical steel sheets without a glass film face challenges in ensuring the adhesion of the tension-insulation coating, leading to inadequate tension imparted to the base steel sheet and increased iron loss.
Innovation Solution
A grain oriented electrical steel sheet is developed without a forsterite film, featuring a base steel sheet with specific chemical composition, an iron oxide layer with controlled thickness and properties, and a tension-insulation coating. The iron oxide layer is formed through a process involving washing, pickling, and heat treatment, ensuring strong adhesion of the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass film is formed on the steel sheet surface, then coating adhesion is improved, but magnetic characteristics deteriorate due to increased iron loss
Solution Approach 1:
The invention removes the glass film (forsterite film) from the steel sheet surface structure. By extracting this layer that causes magnetic deterioration, the patent achieves improved magnetic characteristics while maintaining coating adhesion through alternative means (direct coating on steel sheet surface with proper surface treatment)
Solution Approach 2:
The invention introduces an intermediate layer between the steel sheet and the tension-insulation coating. This intermediate layer serves as a mediator that provides both adhesion functionality and magnetic compatibility, replacing the traditional glass film with a composition that does not hinder domain wall motion
2Loss of energy
If the glass film is removed, then magnetic characteristics improve, but coating adhesion deteriorates
Solution Approach 1:
The invention changes the surface parameters of the steel sheet through controlled oxidation to form a specific oxide layer composition and morphology. By adjusting oxidation conditions (temperature, time, atmosphere), the surface achieves optimal properties for both magnetic performance and coating adhesion without requiring a glass film
Solution Approach 2:
The invention creates a localized oxide layer with specific properties on the steel sheet surface that differs from the bulk material. This surface layer provides the necessary adhesion characteristics while the underlying steel maintains its magnetic properties, achieving local optimization of both adhesion and 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 solution effectively improves the adhesion of the tension-insulation coating on grain oriented electrical steel sheets without a glass film, thereby reducing iron loss and enhancing magnetic characteristics.
Implementation Method 1
an iron oxide layer with controlled thickness and properties, and a tension-insulation coating. The iron oxide layer is formed through a process involving washing, pickling, and heat treatment
Data Source
AI summary
A grain oriented electrical steel sheet includes a base steel sheet, an oxide layer, and a tension-insulation coating. When the iron oxide layer is analyzed by a fourier transform infrared spectroscopy, an absorbance A650 at 650 cm−1 and an absorbance A1250 at 1250 cm−1 satisfy 0.2≤A650/A1250≤5.0. Moreover, a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.