Grain-oriented electrical steel sheet laser processing side strain
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Solution Overview
Problem
Existing methods for manufacturing grain-oriented electrical steel sheets face challenges in minimizing side strain deformation, which affects magnetic properties and yield, due to inaccuracies in controlling grain size and distribution, particularly at the lower end portions of the steel sheet during the finish annealing process.
Innovation Solution
A method involving laser processing after cold rolling, where a laser beam is applied to the steel sheet to form a melted-resolidified portion with controlled depth and width, ensuring an average angular deviation of magnetization easy axes between 20° and 40°, thereby reducing side strain deformation and enhancing magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If grain refining is performed to suppress side strain deformation, then side strain width is reduced, but magnetic properties deteriorate due to abnormal grain formation
Solution Approach 1:
The invention applies different treatments to different regions of the steel sheet. A laser processed portion is formed only in the width direction at specific positions, creating local differences in grain structure. The processed portions have controlled angular deviation (20°-40°) while unprocessed portions maintain normal grain structure, achieving both side strain suppression and magnetic property preservation through spatially differentiated quality
Solution Approach 2:
The invention changes the angular deviation parameter of magnetization easy axes in the laser processed portions to a specific range (20°-40°). This parameter change suppresses side strain deformation while the controlled range prevents excessive deviation that would harm magnetic properties. The continuous annealing process also maintains parameters within optimal ranges to prevent abnormal grain growth
2Manufacturing precision
If high energy laser processing is applied to suppress side strain, then side strain deformation is reduced, but manufacturing cost and complexity increase
Solution Approach 1:
Instead of applying laser processing to the entire steel sheet, the invention applies it partially only to specific regions in the width direction. This partial action is sufficient to suppress side strain deformation without requiring excessive energy or complex equipment. The laser processed portions are strategically positioned to achieve the desired effect with minimal processing
Solution Approach 2:
The steel sheet width is divided into processed and unprocessed regions. The laser processing is segmented into specific width direction positions rather than continuous processing. This segmentation allows side strain suppression at processed locations while maintaining simplicity in unprocessed areas, reducing overall device complexity
3Reliability
If continuous annealing is performed to maintain grain orientation, then magnetic properties are improved, but side strain deformation increases due to prolonged high temperature exposure
Solution Approach 1:
Laser processing is performed before continuous annealing to pre-modify the grain structure in specific regions. This preliminary action creates a grain structure that is more resistant to side strain deformation during the subsequent annealing process. The pre-formed laser processed portions act as anchors that prevent excessive grain boundary sliding during prolonged high temperature exposure
Solution Approach 2:
The laser processing creates melted-resolidified portions with controlled grain orientation before the annealing process begins. This preliminary grain structure formation ensures that during continuous annealing, the grains in processed portions maintain appropriate orientation (20°-40° angular deviation) rather than developing abnormal orientations, thus preventing side strain while preserving magnetic properties
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 effectively minimizes side strain deformation, improves magnetic properties, and increases the yield of grain-oriented electrical steel sheets by precisely controlling the angular deviation of grains, allowing for efficient manufacturing without the need for high-energy pretreatments or frequent device replacements.
Implementation Method 1
irradiating a region on one end side of a steel sheet in a width direction after being subjected to a cold rolling process with a laser beam
Implementation Method 2
forming a melted-resolidified portion with controlled depth and width
Implementation Method 3
performing a finish annealing on the steel sheet which is coiled in a coil shape
Implementation Method 4
the growth time of secondary recrystallization is late compared to the center portion of the coil 5. Therefore, in the lower end portion 5z of the coil 5, the grain size is small
Data Source
AI summary
A method of manufacturing a grain-oriented electrical steel sheet, includes: a laser processing process of forming a laser processed portion by irradiating a region on one end side of a steel sheet in a width direction after being subjected to a cold rolling process with a laser beam along a rolling direction of the steel sheet; and a finish annealing process of coiling the steel sheet with the laser processed portion formed thereon in a coil shape and performing a finish annealing on the coil-shaped steel sheet. In the laser processing process, a melted-resolidified portion having a depth of greater than 0% and equal to or less than 80% of a sheet thickness of the steel sheet is formed by the irradiation of the laser beam at a position corresponding to the laser processed portion.