Grain-Oriented Electrical Steel Composition Without Hot-Rolled Annealing
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Solution Overview
Problem
The challenge is to produce a grain oriented electrical steel sheet with improved magnetic properties without the need for hot-rolled sheet annealing, which is costly and prone to thermal deviations leading to magnetism deterioration.
Innovation Solution
The solution involves adjusting the content of Si, C, N, Cr, Sn, and coiling temperature during the hot-rolling process to inhibit magnetism deterioration, using specific alloy compositions and annealing steps such as primary and secondary recrystallization annealing, while omitting hot-rolled sheet annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot-rolled sheet annealing is performed to uniformly control microstructure and inclusions, then magnetic properties are improved, but production cost increases and productivity decreases
Solution Approach 1:
The invention performs preliminary actions during hot-rolling by precisely controlling alloy composition (Si: 2.0-4.0%, Mn: 0.04-0.2%, Sn: 0.03-0.08%, Cr: 0.01-0.2%, C: 0.005% or less, N: 0.010% or less) and coiling temperature (500-850°C) to ensure uniform microstructure and inclusion distribution before annealing, eliminating the need for hot-rolled sheet annealing while maintaining magnetic properties
Solution Approach 2:
The invention changes key parameters including alloy composition ranges and coiling temperature to achieve uniform microstructure and inclusion control during hot-rolling, replacing the traditional hot-rolled sheet annealing process while maintaining or improving magnetic properties
2Productivity
If hot-rolled sheet annealing is omitted to reduce cost, then production cost decreases, but thermal deviation causes microstructure non-uniformity and magnetism deterioration
Solution Approach 1:
The invention performs preliminary uniformity control during hot-rolling by optimizing alloy composition and coiling temperature to prevent microstructure non-uniformity and inclusion aggregation, eliminating the need for hot-rolled sheet annealing while avoiding magnetism deterioration
Solution Approach 2:
The invention changes coiling temperature range (500-850°C) and alloy composition parameters to control thermal deviation effects during hot-rolling, achieving uniform microstructure without hot-rolled sheet annealing while maintaining magnetic properties
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 effectively reduces thermal deviations and microstructure non-uniformity, resulting in improved magnetic properties and reduced production costs by stabilizing the grain oriented electrical steel sheet.
Implementation Method 1
inclusions comprising at least one from among AlN, (Al,Si)N, (Al,Si,Mn)N, MnS, CuS, and Al2O3, in which an average diameter of the inclusions may be 0.5 to 6.0 μm
Implementation Method 2
performing primary recrystallization annealing on the cold-rolled steel sheet
Implementation Method 3
a grain oriented electrical steel sheet is a soft magnetic material having excellent magnetic properties in one direction or a rolling direction since a texture of a bloom with respect to the rolling direction is a Goss texture, which is {110}
Data Source
AI summary
A grain-oriented electrical steel sheet according to an embodiment of the present invention comprises, by wt %, 2.0-4.0% of Si, 0.04-0.2% of Mn, 0.010% or less of N (excluding 0%), 0.005% or less of C (excluding 0%), 0.03-0.08% of Sn and 0.01-0.2% of Cr, the balance of Fe and inevitable impurities, and inclusions comprising at least one from among AlN, (Al,Si)N, (Al,Si,Mn)N, MnS, CuS and Al2O3, wherein the average diameter of the inclusions is 0.5-6.0 μm, and 40-130/mm2 inclusions having a diameter of 6.0 μm or less from among the inclusions can be included.