Grain-Oriented Electrical Steel Domain Refinement by Variable Spacing
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Solution Overview
Problem
Existing methods for manufacturing grain-oriented electrical steel sheets struggle to optimize magnetic properties due to limitations in measuring and adjusting grain sizes in real-time, especially when the sheets are insulated and coated, leading to inefficiencies in energy loss and magnetic flux density.
Innovation Solution
The method involves forming linear deformable portions on the steel sheet with varying intervals that correspond to grain sizes, using a combination of laser irradiation, electron beams, or plasma, and acid etching to refine magnetic domains, ensuring that the grain size and interval satisfy a specific equation to enhance magnetism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the hydrochloric acid immersion method is used to measure grain size, then grain size can be measured clearly, but the method cannot be used in real-time and is limited to non-destructive measurement of insulation-coated electrical steel sheets
Solution Approach 1:
The patent replaces the chemical etching method (hydrochloric acid immersion) with a non-contact optical measurement system using a line sensor and light source. This substitution enables real-time grain size measurement during the manufacturing process without requiring acid immersion, thereby resolving the contradiction between measurement precision and real-time measurement capability.
2Ease of manufacture
If deformable portions are formed at fixed intervals, then the manufacturing process is simple, but magnetic properties cannot be optimized for varying grain sizes across the steel sheet
Solution Approach 1:
The patent implements a dynamic interval control system where the distance between deformable portions is adjusted based on real-time grain size measurements. The control unit varies the interval of deformable portions according to the measured grain size distribution, enabling magnetic property optimization while maintaining manufacturing feasibility through automated control.
Solution Approach 2:
The patent applies different intervals of deformable portions to different regions of the steel sheet based on local grain size characteristics. By matching the interval to the local grain size, each region receives optimized treatment for its specific magnetic properties, resolving the contradiction between manufacturing simplicity and magnetic property optimization.
3Productivity
If grain size is not measured and controlled, then the manufacturing process is faster, but magnetic properties such as iron loss and magnetic flux density cannot be optimized
Solution Approach 1:
The patent implements continuous grain size measurement and continuous adjustment of deformable portion intervals during the manufacturing process. The line sensor continuously measures grain size as the steel sheet passes through, and the control unit continuously adjusts the interval, maintaining both high productivity and precise magnetic property control through uninterrupted measurement and adjustment.
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 improves magnetic domain refinement, reducing energy loss and enhancing magnetic properties by adjusting deformable portion intervals based on measured grain sizes, resulting in improved iron loss characteristics and magnetism.
Implementation Method 1
irradiating a laser beam a plurality of times at a predetermined interval in a rolling direction on a surface of the silicon steel sheet from one end to the other end of the silicon steel sheet along a sheet width direction. While the secondary recrystallization is caused, grain boundaries passing from a front surface to a rear surface of the silicon steel sheet are generated along paths of the laser beams.
Implementation Method 2
EP 0 287 357 A2 describes a method of reducing iron loss of a grain oriented silicon steel sheet by irradiating a plasma flame to the surface of the grain oriented silicon steel sheet after the final annealing.
Data Source
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AI summary
A grain-oriented electrical steel sheet includes a plurality of linear deformable portions formed on a surface of the electrical steel sheet in a rolling direction, wherein an interval between the deformable portions changes to correspond to a grain size of grains over the entire length of the steel sheet, and at least two regions in which intervals between the deformable portions are different exist.