Oriented Electrical Steel Composition for Stable Goss Grain Growth
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Solution Overview
Problem
Existing methods for producing oriented electrical steel sheets with high magnetic properties and stable Goss orientation during secondary recrystallization are complex, require stringent process control, and are limited by the use of high-temperature nitriding processes that can lead to yield reductions and process complexity.
Innovation Solution
A method involving controlled alloying with S- and Se-based precipitates, specifically managing the correlation between Mn, Cu, S, Se, Al, and N, to stabilize grain growth during secondary recrystallization high temperature annealing, using a simplified process that avoids high-temperature nitriding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature nitriding process is used to form AlN-based nitride precipitates as grain growth inhibitors, then secondary recrystallization can be formed, but the process complexity increases and yield decreases due to slab washing phenomenon
Solution Approach 1:
The patent extracts and eliminates the high-temperature nitriding process from the production method. Instead of using AlN-based nitride precipitates formed through nitriding, the invention uses S- and Se-based precipitates that form naturally during conventional hot rolling without requiring additional nitriding equipment or process steps, thereby removing the source of process complexity and yield loss
Solution Approach 2:
The patent changes the chemical composition parameters by controlling the correlations between Mn, Cu, S, and Se contents in the steel slab. By adjusting these compositional parameters within specific ranges and satisfying particular ratio relationships, the desired precipitate formation is achieved without requiring high-temperature nitriding, thus simplifying the process while maintaining reliable secondary recrystallization
2Reliability
If high-temperature nitriding process is used to form AlN-based nitride precipitates as grain growth inhibitors, then secondary recrystallization can be formed, but actual yield decreases due to slab washing phenomenon
Solution Approach 1:
The patent removes the high-temperature nitriding process from the production flow, eliminating the slab washing phenomenon that causes yield loss. The S- and Se-based precipitates form during standard hot rolling operations, avoiding the need for separate nitriding treatment that would expose slabs to washing conditions
Solution Approach 2:
The patent enables the steel slab to self-form the necessary grain growth inhibitors (S- and Se-based precipitates) during the inherent hot rolling process through controlled composition. The alloying elements Mn, Cu, S, and Se work together to automatically generate the required precipitate structure without external intervention, preventing yield loss from additional processing steps
3Reliability
If complex processes such as component control, slab reheating, hot rolling, and multiple annealing are used to grow grains with high Goss orientation integration, then magnetic properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the compositional parameters of Mn, Cu, S, and Se within specific ranges and establishes particular ratio relationships between them. This controlled composition enables the formation of S- and Se-based precipitates with appropriate characteristics during hot rolling, simplifying the overall process while achieving the desired grain growth and magnetic properties
Solution Approach 2:
The patent creates a composite effect by combining multiple alloying elements (Mn, Cu, S, Se) in specific proportions. This composite approach allows the elements to work synergistically, forming complex precipitate structures that effectively control grain growth during hot rolling, thereby achieving high Goss orientation integration through a simplified process
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
The method achieves improved magnetic properties with stable grain integration into Goss orientation, reducing iron loss and enhancing transformer efficiency, while simplifying the production process and avoiding yield reductions.
Implementation Method 1
the precipitates that inhibit the grain growth are specifically referred to as grain growth inhibitors
Implementation Method 2
movement of a grain boundary in which grains normally grow is suppressed by precipitates, inclusions, or elements that are dissolved or segregated in the grain boundaries
Implementation Method 3
secondary recrystallization high temperature annealing
Implementation Method 4
using S- and Se-based precipitates... by controlling a correlation between Mn, Cu, S, Se, Al, and N in an alloy component
Data Source
AI summary
An oriented electrical steel sheet according to an embodiment of the present invention includes, in a unit of wt %, Si at 1.0 wt % to 5.0 wt %, C at 0.005 wt % or less (excluding 0 wt %), Mn at 0.001 wt % to 0.1 wt %, Cu at 0.001 wt % to 0.1 wt %, S at 0.001 wt % to 0.020 wt %, Se at 0.001 wt % to 0.050 wt %, Al at 0.0005 wt % to 0.010 wt %, N at 0.0005 wt % to 0.005 wt %, and the remainder of Fe and inevitable impurities.The oriented electrical steel sheet according to the embodiment of the present invention satisfies Equation 1.16≤(10×[Mn]+[Cu])/([S]+[Se])+(0.02−[Al])/[N]≤20 [Equation 1](In Equation 1, [Mn], [Cu], [S], [Se], [Al], and [N] represent contents (wt %) of Mn, Cu, S, Se, Al, and N, respectively.)