Grain-Oriented Steel Laser Groove Iron Loss
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Solution Overview
Problem
Current methods for reducing iron loss in grain-oriented electrical steel sheets, such as forming grooves and crystal grain boundaries, are inefficient and costly due to the need for precise treatment processes, which hinder mass production and productivity.
Innovation Solution
A grain-oriented electrical steel sheet is manufactured using a laser beam to form grooves along the sheet width direction, with crystal grain boundaries extending from the front to the back surface, and a glass coating applied, optimizing the X-ray intensity ratio of Mg to enhance magnetic domain subdivision and reduce iron loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a groove is formed in the surface of a ferrite and a crystal grain boundary is formed from the bottom portion of the groove to the rear surface, then iron loss is significantly reduced, but productivity is significantly reduced due to the complexity of the treatment process
Solution Approach 1:
The groove is formed on the surface of the ferrite before the crystal grain boundary formation treatment. This preliminary action allows the subsequent heat treatment or strain application to automatically form the crystal grain boundary extending from the groove bottom to the rear surface, eliminating the need for separate precise alignment and treatment steps.
Solution Approach 2:
The formation of the groove and the crystal grain boundary are combined into a simplified process sequence. The groove formation serves as a precursor that guides the crystal grain boundary development during heat treatment, merging what would otherwise be separate complex steps into an integrated process that maintains effectiveness while improving productivity.
2Loss of energy
If the width of the groove is set to be narrow (30 to 300 μm) to obtain the desired effect, then iron loss is reduced, but it becomes difficult to perform treatment such as attachment of Sn, addition of strain, or radiation of laser light in exact conformity with the narrow groove
Solution Approach 1:
The groove is formed first as a preliminary structure with predetermined dimensions. This pre-formed groove serves as a template that guides the subsequent crystal grain boundary formation, ensuring that even narrow grooves (30-300 μm) can be precisely replicated without requiring complex real-time alignment during the treatment process.
Solution Approach 2:
The groove structure itself serves the dual function of both a physical feature for magnetic domain subdivision and a guide template for crystal grain boundary formation. The groove's predetermined geometry automatically defines the path and dimensions of the crystal grain boundary during heat treatment, eliminating the need for external alignment assistance.
3Ease of manufacture
If electrolytic etching is used to form a groove, then a groove can be formed, but the number of processes and treating time significantly increase due to the need for application of resist, corrosion treatment, removal of resist, and cleaning
Solution Approach 1:
The invention extracts and eliminates the unnecessary process steps from the traditional electrolytic etching sequence. By using laser beam scanning to form the groove directly, the patent removes the steps for resist application, etching solution corrosion, resist removal, and cleaning, retaining only the essential groove formation function.
Solution Approach 2:
The mechanical and chemical electrolytic etching process is replaced with a laser-based optical/thermal process. The laser beam scanning method uses focused light energy to directly ablate or melt the material and form the groove, substituting the complex electrochemical system with a more direct and efficient energy-based approach.
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 method allows for the industrial mass-production of grain-oriented electrical steel sheets with low iron loss, improving magnetic characteristics while simplifying the manufacturing process and reducing treatment time.
Implementation Method 1
a groove formed from a locus of a laser beam which is scanned from one end edge to the other end edge in a sheet width direction
Implementation Method 2
a glass coating may be formed in the groove
Implementation Method 3
annealing, the introduced strain is relaxed
Implementation Method 4
a crystal grain boundary which extends along the groove and penetrates the grain-oriented electrical steel sheet from a front surface to back surface
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
This method of manufacturing a grain-oriented electrical steel sheet includes, between a cold rolling process and a winding process, a groove formation process of irradiating the surface of a silicon steel sheet with a laser beam multiple times at predetermined intervals in a sheet passing direction, over an area from one end edge to the other end edge, in a sheet width direction of the silicon steel sheet, thereby forming a groove along a locus of the laser beam, wherein when the average intensity of the laser beam is set to be P (W), a focusing diameter in the sheet passing direction of a focused spot of the laser beam is set to be Dl (mm), a focusing diameter in the sheet width direction is set to be Dc (mm), a scanning speed in the sheet width direction of the laser beam is set to be Vc (mm/s), an irradiation energy density Up of the laser beam is represented by the following Formula 1, and an instantaneous power density Ip of the laser beam is represented by following Formula 2, following formulae 3 and 4 are satisfied.