Grain-oriented electrical steel sheet Cu stabilization
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Solution Overview
Problem
Conventional grain-oriented electrical steel sheets face challenges in achieving uniform magnetic properties across the entire length of the steel sheet coil due to temperature fluctuations during high-temperature slab heating, leading to inhibitor deficiency and non-homogeneous magnetic properties.
Innovation Solution
Incorporating a molten steel with a specific chemical composition, including 0.10% or more of Cu, and controlling the thermal history during hot rolling to suppress the formation of Cu sulfide, ensuring stable precipitation of MnS and AlN, which enhances the magnetic properties and reduces material variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature slab heating (1300°C or more) is used to achieve uniform solution of MnS and fine precipitation, then magnetic property can be improved, but temperature fluctuation at leading end and rear end of slab occurs, causing non-homogeneous magnetic property
Solution Approach 1:
The invention changes the chemical composition parameters by adding Cu (0.03-1.00 mass%) to the steel. This parameter change suppresses the formation of Cu sulfide and stabilizes MnS precipitation behavior during hot rolling, thereby achieving homogeneous magnetic properties across the entire steel sheet coil including leading end and rear end portions.
Solution Approach 2:
Cu acts as an intermediary element that modifies the precipitation behavior of MnS. By adding Cu, the invention mediates the temperature dependence of MnS solution and precipitation, making it less sensitive to temperature fluctuations during hot rolling and achieving more uniform magnetic properties.
2Manufacturing precision
If Cu is added to suppress temperature dependence of MnS solution and precipitation, then magnetic property uniformity can be improved, but Cu sulfide formation becomes likely, causing property deterioration at coil ends
Solution Approach 1:
The invention optimizes the Cu content parameter within a specific range (0.03-1.00 mass%) and controls the S content (0.005-0.050 mass%) to prevent Cu sulfide formation. By carefully adjusting these compositional parameters, the invention achieves stable MnS precipitation without triggering harmful Cu sulfide formation, even at coil ends.
Solution Approach 2:
The invention addresses the local quality issue at coil ends by controlling the overall compositional parameters and thermal history. The specific Cu and S content ranges are designed to prevent Cu sulfide formation in high-temperature zones (coil ends) while maintaining beneficial MnS precipitation throughout the entire steel sheet.
3Reliability
If thermal history is controlled to suppress Cu sulfide formation, then property deterioration at coil ends can be prevented, but manufacturing process complexity increases
Solution Approach 1:
The invention simplifies thermal history control by establishing specific compositional parameters (Cu: 0.03-1.00 mass%, S: 0.005-0.050 mass%) that inherently suppress Cu sulfide formation. Once these compositional parameters are set, the material becomes more tolerant to thermal history variations, reducing the complexity of process control while maintaining reliable 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 results in a low-core loss, uniform, and stable magnetic property across the entire length of the steel sheet coil by stabilizing secondary recrystallization and preventing the formation of thermally unstable Cu sulfide, thereby improving the grain-oriented electrical steel sheet's performance.
Implementation Method 1
stable precipitation of MnS and AlN
Implementation Method 2
sharpen secondary recrystallization in the Goss orientation
Data Source
AI summary
A grain-oriented electrical steel sheet includes: a chemical composition represented by, in mass %, Si: 2.0% to 5.0%, Mn: 0.03% to 0.12%, Cu: 0.10% to 1.00%, sb or Sn, or both thereof: 0.000% to 0.3% in total, Cr: 0% to 0.3%, P: 0% to 0.5%, Ni: 0% to 1%, and the balance: Fe and impurities, in which an L-direction average diameter of crystal grains observed on a surface of the steel sheet in an L direction parallel to a rolling direction is equal to or more than 3.0 times a C-direction average diameter in a C direction vertical to the rolling direction.