Non-oriented Electrical Steel Sheet Composition for High Saturation Flux Density
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Solution Overview
Problem
Conventional non-oriented electrical steel sheets face challenges in reducing high-frequency iron loss while maintaining high saturation magnetic flux density and productivity, particularly when silicon content exceeds 3%, leading to brittleness and poor magnetic properties.
Innovation Solution
A non-oriented electrical steel sheet composition with specific ranges of Si, sol.Al, Mn, and other elements, along with a manufacturing process involving hot-rolling, annealing, pickling, cold-rolling, and final-annealing, is used to achieve reduced high-frequency iron loss and increased saturation magnetic flux density without compromising productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the amount of Si is increased to reduce high-frequency iron loss, then resistivity increases and iron loss decreases, but the steel sheet becomes significantly brittle and saturation magnetic flux density decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters within specific ranges: Si at 3.0-3.7%, sol.Al at 0.3-1.0%, and Mn at 0.5-1.5%, along with their interaction parameter Si + (2/3)×sol.Al + (1/5)×Mn ≤ 4.25. This systematic parameter optimization allows the steel sheet to achieve high resistivity (≥60 μΩcm) for reduced iron loss while maintaining adequate ductility for manufacturing productivity.
2Loss of energy
If the amount of Si is increased to increase resistivity, then eddy current loss decreases, but saturation magnetic flux density Bs is reduced
Solution Approach 1:
The patent employs composite material principles by creating a multi-element alloy system combining Si, sol.Al, and Mn in specific proportions. This composite approach allows the steel to achieve resistivity ≥60 μΩcm (reducing eddy current loss) while maintaining saturation magnetic flux density ≥1.945T, as the combined effect of these elements optimizes both electrical and magnetic properties better than any single element alone.
3Loss of energy
If alloying elements are added to increase resistivity, then iron loss is reduced, but the steel sheet becomes brittle
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters within specific ranges: Si at 3.0-3.7%, sol.Al at 0.3-1.0%, and Mn at 0.5-1.5%, along with their interaction parameter Si + (2/3)×sol.Al + (1/5)×Mn ≤ 4.25. This systematic parameter optimization allows the steel sheet to achieve high resistivity (≥60 μΩcm) for reduced iron loss while maintaining adequate ductility for manufacturing productivity.
4Loss of energy
If the amount of Si exceeds 3%, then resistivity increases, but brittleness becomes notable and magnetic properties deteriorate
Solution Approach 1:
The patent employs composite material principles by creating a multi-element alloy system combining Si, sol.Al, and Mn in specific proportions. This composite approach allows the steel to achieve resistivity ≥60 μΩcm (reducing eddy current loss) while maintaining saturation magnetic flux density ≥1.945T, as the combined effect of these elements optimizes both electrical and magnetic properties better than any single element alone.
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 approach results in a steel sheet with improved magnetic properties, reduced brittleness, and enhanced productivity, suitable for high-performance motors in hybrid vehicles and household appliances.
Implementation Method 1
the iron loss can be reduced by increasing the resistivity of the non-oriented electrical steel sheet
Implementation Method 2
after the cold-rolling, applying final-annealing
Data Source
Figure 1
AI summary
This oriented electrical steel sheet is a non-oriented electrical steel sheet consisting of, in mass%: C: not less than 0.0001% and not more than 0.0040%, Si: more than 3.0% and not more than 3.7%, sol.Al: not less than 0.3% and not more than 1.0%, Mn: not less than 0.5% and not more than 1.5%, Sn: not less than 0.005% and not more than 0.1%, Ti: not less than 0.0001% and not more than 0.0030%, S: not less than 0.0001% and not more than 0.0020%, N: not less than 0.0001% and not more than 0.003%, Ni: not less than 0.001% and not more than 0.2%, P: not less than 0.005% and not more than 0.05%, with a balance consisting of Fe and impurities, in which a resistivity p at room temperature ≥ 60 µΩcm, and saturation magnetic flux density Bs at room temperature ≥ 1.945T are established, and the components contained satisfy 3.5 ≤ Si + (2/3) × sol.Al + (1/5) × Mn ≤ 4.25.