Grain-Oriented Electrical Steel Heating for Balanced Goss Texture
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Solution Overview
Problem
Existing methods for producing grain-oriented electrical steel sheets face challenges in achieving stable improvement of magnetic properties due to excessive introduction of shear bands during cold rolling, which hinders the growth of Goss-oriented grains, and rapid heating methods in decarburization annealing lead to imbalanced grain orientations, failing to meet energy-saving demands.
Innovation Solution
Optimize the conditions of aging during cold rolling and temperature maintaining treatment in decarburization annealing by performing final cold-rolling at 150° C. to 350° C. and rapid heating at 250° C./s with a temporary reduction in heating rate during decarburization annealing, using a transverse induction heating device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rapid heating is performed during decarburization annealing to promote Goss-oriented grain formation, then the proportion of Goss-oriented grains increases, but γ-fiber texture develops excessively leading to imbalanced grain orientation
Solution Approach 1:
The patent applies periodic action by implementing a two-stage heating process: first rapid heating at 250°C/s or more to promote Goss-oriented grain formation, then temporary heating rate reduction to 10°C/s or less in the 500-700°C range for 1-10 seconds to suppress γ-fiber texture development. This periodic variation in heating rate achieves balanced grain orientation that would not be possible with constant heating rates.
Solution Approach 2:
The patent employs dynamics by making the heating rate adjustable and variable during the annealing process. Instead of using a fixed heating rate, the system dynamically changes the heating rate based on the temperature stage: high heating rate (≥250°C/s) in the 400-700°C range to promote nucleation, then low heating rate (≤10°C/s) in the 500-700°C range to control growth, thereby achieving optimal texture control.
2Quantity of substance
If aging treatment is performed during cold rolling to increase Goss-oriented grains, then the number of Goss nuclei increases, but excessive shear band introduction hinders Goss grain growth during secondary recrystallization
Solution Approach 1:
The patent applies parameter changes by optimizing the aging treatment parameters during cold rolling: performing aging at temperatures of 150°C to 350°C for controlled time periods, and adjusting the degree of reduction in each rolling pass. These parameter optimizations ensure sufficient Goss nucleus formation without creating excessive shear bands that would impede subsequent grain growth.
Solution Approach 2:
The patent uses partial action by applying aging treatment selectively during specific stages of cold rolling rather than continuously. The aging treatment is applied in a controlled manner during intermediate stages to generate sufficient Goss nuclei, while avoiding excessive aging that would create too many shear bands and hinder final grain growth.
3Stability of the object's composition
If the heating rate is reduced temporarily during rapid heating to suppress γ-fiber texture, then grain orientation balance improves, but the overall heating time increases
Solution Approach 1:
The patent applies periodic action by implementing a two-stage heating process: first rapid heating at 250°C/s or more to promote Goss-oriented grain formation, then temporary heating rate reduction to 10°C/s or less in the 500-700°C range for 1-10 seconds to suppress γ-fiber texture development. This periodic variation in heating rate achieves balanced grain orientation that would not be possible with constant heating rates.
Solution Approach 2:
The patent employs dynamics by making the heating rate adjustable and variable during the annealing process. Instead of using a fixed heating rate, the system dynamically changes the heating rate based on the temperature stage: high heating rate (≥250°C/s) in the 400-700°C range to promote nucleation, then low heating rate (≤10°C/s) in the 500-700°C range to control growth, thereby achieving optimal texture control.
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
Stably produces grain-oriented electrical steel sheets with excellent magnetic properties, reducing iron loss and contributing to energy savings in electrical devices.
Implementation Method 1
heating a steel sheet from room temperature to a temperature around the recrystallization temperature in a short time using, for example, electric heating or induction heating
Implementation Method 2
rapidly heating a steel sheet during a heating step of decarburization annealing
Implementation Method 3
decarburization annealing which also serves as primary recrystallization annealing
Implementation Method 4
promoting the diffusion of dissolved carbon (C) and nitrogen (N) to pin a dislocation introduced by cold rolling
Implementation Method 5
secondary recrystallization annealing
Data Source
AI summary
A method for a grain-oriented electrical steel sheet including subjecting a steel material with a predetermined component composition to hot rolling and then to cold rolling to obtain a cold-rolled sheet with a final thickness and subjecting the cold-rolled sheet to decarburization annealing serving as primary recrystallization annealing and then to finishing annealing, in which a final cold-rolling step of the cold rolling includes at least one rolling pass or more performed with the temperature of the steel sheet set in the range of 150° C. to 350° C. inclusive, and the decarburization annealing includes a heating step in which the steel sheet is heated at an average heating rate of 250° C./s or more from 400° C. to a temperature T(° C.) of 700 to 900° C. and then held at a heating rate of 2/3 of the average heating rate or less in any of temperature ranges between 500° C. and 700° C. for a time of 0.10 seconds or more but less than 1.00 seconds. Thus, a grain-oriented electrical steel sheet with excellent magnetic properties is obtained. A transverse induction heating device is used for the rapid heating.