Grain-Oriented Electrical Steel Aging for Carbon Diffusion Control
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Solution Overview
Problem
The magnetic properties of grain-oriented electrical steel sheets need further improvement despite existing efforts to control solute C and carbides.
Innovation Solution
Limiting the aging amount of carbon during the aging period from the completion of cooling in annealing before final cold rolling to biting in the final cold rolling to a specific range, defined by a diffusion distance of 0.02 μm to 0.5 μm, to enhance the magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cooling and aging treatment is applied to increase solute C and precipitate carbides, then Cottrell atmosphere is created and {110} strength is increased, but magnetic properties need further improvement
Solution Approach 1:
The invention changes the parameter of aging amount from uncontrolled or conventionally controlled to precisely controlled within 0.02-0.5 μm diffusion distance. This is achieved by controlling cooling rate (150°C/min or more), holding temperature (60°C or lower for at least 95% of aging period), and aging time to achieve the specific diffusion distance range, thereby optimizing magnetic properties
Solution Approach 2:
The invention replaces conventional qualitative control of aging treatment with quantitative measurement and control of carbon diffusion distance. By introducing the specific parameter of diffusion distance (0.02-0.5 μm) as a measurable and controllable parameter, the process transitions from empirical control to precision control, improving magnetic properties
2Quantity of substance
If cooling rate is increased to 150°C/min or more to increase solute C, then Cottrell atmosphere formation is enhanced, but control precision of aging amount becomes more difficult
Solution Approach 1:
The invention implements feedback control by monitoring and adjusting the aging process based on the target diffusion distance of 0.02-0.5 μm. The cooling rate, holding temperature, and aging time are controlled to achieve the desired carbon diffusion distance, ensuring precise control of aging amount while maintaining adequate solute C concentration
3Shape
If aging treatment is performed to precipitate fine carbides of 100 Å to 500 Å, then texture improvement is achieved, but further magnetic property enhancement is needed
Solution Approach 1:
The invention optimizes the parameter of carbide particle size by controlling the aging process to achieve a diffusion distance of 0.02-0.5 μm. This precise control of carbon diffusion results in optimal carbide precipitation that enhances both texture and magnetic properties, with holding temperature at 60°C or lower for at least 95% of the aging period
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 allows for the production of grain-oriented electrical steel sheets with improved magnetic flux density and properties.
Implementation Method 1
a total aging amount of carbon during a period from completion of cooling in annealing before the final cold rolling to biting in the final cold rolling is 0.02 μm to 0.5 μm in terms of diffusion distance of carbon
Data Source
AI summary
Provided is a grain-oriented electrical steel sheet having excellent magnetic properties. In an aging treatment method of subjecting a steel sheet before final cold rolling to aging treatment in a process of producing a grain-oriented electrical steel sheet, a total aging amount of carbon during a period from completion of cooling in annealing before the final cold rolling to biting in the final cold rolling is 0.02 μm to 0.5 μm in terms of diffusion distance of carbon.