Non-Oriented Electrical Steel Texture Balance for Angular Flux Uniformity
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Solution Overview
Problem
The existing methods for producing non-oriented electrical steel sheets face challenges in achieving both high magnetic performance and mass production, particularly due to large magnetic flux density deviations for each angle and restrictions on productivity.
Innovation Solution
A non-oriented electrical steel sheet with a specific composition and controlled texture, where the strengths of {111} and {100} orientations at a thickness middle portion are balanced within certain ranges, allowing for the omission of hot-band annealing and enabling efficient mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot-band annealing is performed to improve magnetic flux density, then magnetic performance is improved, but anisotropy of magnetic characteristics increases and productivity is restricted
Solution Approach 1:
The patent removes the hot-band annealing step from the production process entirely. By extracting this problematic process step, the patent eliminates the cause of magnetic anisotropy while maintaining productivity. The invention achieves this by controlling the finishing hot rolling temperature and coiling temperature to directly produce the desired texture without requiring subsequent annealing.
Solution Approach 2:
The patent changes the temperature parameters of the hot rolling and coiling processes to achieve the desired crystal texture. Specifically, it controls the finishing hot rolling temperature to 800°C or lower and the coiling temperature to 750°C or lower, which fundamentally alters the phase transformation behavior and results in reduced magnetic anisotropy without needing hot-band annealing.
2Reliability
If hot-band annealing is performed to improve magnetic flux density, then magnetic performance is improved, but magnetic flux density deviation for each angle increases
Solution Approach 1:
The patent changes the temperature parameters of the hot rolling and coiling processes to achieve the desired crystal texture. Specifically, it controls the finishing hot rolling temperature to 800°C or lower and the coiling temperature to 750°C or lower, which fundamentally alters the phase transformation behavior and results in reduced magnetic anisotropy without needing hot-band annealing.
Solution Approach 2:
The patent performs the texture control action during the hot rolling and coiling processes themselves, before any annealing would occur. By establishing the desired crystal orientation distribution during these preliminary steps through controlled cooling, the patent prevents magnetic anisotropy from developing in the first place.
3Productivity
If finishing hot rolling temperature is reduced to 800°C or lower to omit hot-band annealing, then productivity is improved, but rolling load must be increased
Solution Approach 1:
The patent changes the temperature parameters of the hot rolling and coiling processes to achieve the desired crystal texture. Specifically, it controls the finishing hot rolling temperature to 800°C or lower and the coiling temperature to 750°C or lower, which fundamentally alters the phase transformation behavior and results in reduced magnetic anisotropy without needing hot-band annealing.
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 proposed solution results in a non-oriented electrical steel sheet with reduced magnetic flux density deviation for each angle, improved magnetic characteristics, and enhanced productivity, suitable for motor cores.
Implementation Method 1
a slab heating temperature is 1050 to 1250°C, a steel sheet surface temperature during passing through a final stand of finish rolling in the hot rolling is 800 to 1000°C
Data Source
AI summary
A non-oriented electrical steel sheet according to an aspect of the present invention includes a composition containing, in mass %, C: 0.0005 to 0.0030%, Si: 1.5 to 3.5%, Al: 0.10 to 2.00%, Mn: 0.1 to 2.0%, P: 0.180% or less, S: 0.0005 to 0.0030%, N: 0.0005 to 0.0030%, Ti: 0.0005 to 0.0030%, B: 0 to 0.0020%, and Sn+2×Sb: 0 to 0.25%; and the remainder being Fe and impurities, wherein 2≤A≤10, 1.0≤B≤10, and 0.8≤B/A≤1.0 are satisfied in which a sheet thickness is t, a strength of a {111}<112> orientation, a crystal orientation measured at a position in a range of 2/5 t to 3/5 t is A, and a strength of a {100}<012> orientation measured at the position in a range of 2/5 t to 3/5 t is B.