Grain-Oriented Steel Sheet Noise Reduction via Forsterite Film Tension
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Solution Overview
Problem
Grain oriented electrical steel sheets subjected to magnetic domain refining treatments exhibit significant noise and inadequate iron loss properties when assembled into transformers, necessitating improvements in magnetic domain refinement techniques.
Innovation Solution
A grain oriented electrical steel sheet with a forsterite film and subjected to electron beam irradiation, where the tension of the forsterite film is 2.0 MPa or higher, and the relationship between the thermal strain-induced region diameter and electron beam irradiation pitch is controlled within specific ratios, optimizing the magnetic domain refining process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If magnetic domain refining treatment is performed by electron beam irradiation, then iron loss is reduced, but noise increases significantly
Solution Approach 1:
The invention changes the physical parameters of the steel sheet surface by controlling the thickness (5-20 μm) and material composition (oxide layer, silicate coating, or phosphate coating) of the surface layer. This parameter modification allows the surface layer to absorb or dampen the noise generated during magnetic domain refining, while still permitting the electron beam treatment to reduce iron loss in the bulk material.
Solution Approach 2:
The surface layer acts as an intermediary between the electron beam irradiation and the noise propagation. It serves as a buffer that can absorb the mechanical vibrations and noise generated during magnetic domain refining, while allowing the electron beam to penetrate and perform the iron loss reduction treatment in the underlying steel sheet.
2Manufacturing precision
If magnetic domain refining treatment is performed by electron beam irradiation, then magnetic domain width is reduced, but iron loss properties remain inadequate
Solution Approach 1:
The invention modifies the surface parameters (thickness 5-20 μm, material composition) to create a surface layer that complements the electron beam treatment. This surface modification enhances the overall effectiveness of magnetic domain refinement and improves iron loss properties that cannot be achieved by electron beam irradiation alone.
Solution Approach 2:
The steel sheet becomes a composite structure with a surface layer (oxide, silicate, or phosphate coating) combined with the bulk steel material. This composite structure allows the surface layer to contribute to magnetic domain control and iron loss reduction, working synergistically with the electron beam treated bulk material.
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 reduces iron loss and noise in transformers, enhancing the magnetic domain refining effect and maintaining low iron loss properties.
Implementation Method 1
tension exerted on the steel sheet by the forsterite film is 2.0 MPa or higher
Implementation Method 2
magnetic domain refining treatment by means of electron beam irradiation
Implementation Method 3
diameter of a thermal strain introduced region (A)
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3~4
AI summary
The present invention provides a grain oriented electrical steel sheet that has been subjected to magnetic domain refining treatment by means of electron beam irradiation and exhibits excellent low-noise properties when assembled as an actual transformer, in which tension exerted on the steel sheet by the forsterite film is 2.0 MPa or higher both in a rolling direction and a direction transverse (perpendicular) to the rolling direction, and a ratio of an irradiation pitch in a thermal strain introduced region (B) to a spot diameter (A) on an electron beam irradiation surface satisfies a relation: 0.5 ≤ B/A ≤ 5.0.