Grain-Oriented Steel Sheet Magnetic Stability
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Solution Overview
Problem
Grain-oriented electrical steel sheets produced without inhibitors exhibit sensitive magnetic properties due to nonuniform primary recrystallization microstructures, leading to variations in iron loss and magnetic flux density along the coil length.
Innovation Solution
Control the dispersion of oxide particles containing Ca and/or Mg to 400 or less per unit area in the transverse cross-section, ensuring uniform precipitation and reducing the impact of impurities, thereby stabilizing magnetic properties throughout the coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the method for promoting secondary recrystallization without an inhibitor is used, then production costs are reduced, but magnetic properties become sensitive to changes in production conditions and nonuniform along the coil length
Solution Approach 1:
The invention changes the physical-chemical parameters of the steel slab by controlling the content of specific elements (Al: 0.003-0.05 mass%, S: 0.003-0.03 mass%, Se: 0.003-0.02 mass%, B: 0.0003-0.005 mass%) to enable secondary recrystallization without traditional inhibitors, while maintaining stable magnetic properties through optimized composition ranges
Solution Approach 2:
The invention creates local quality differences by introducing specific impurity elements at controlled low concentrations that act as nucleation sites for uniform primary recrystallization, ensuring uniform grain structure and stable magnetic properties in specific regions throughout the coil length
2Productivity
If inhibitor-forming elements are completely removed from the slab, then secondary recrystallization is promoted, but primary recrystallization microstructure becomes nonuniform
Solution Approach 1:
The invention uses trace amounts of specific elements (Al, S, Se, B) as intermediary substances that facilitate uniform primary recrystallization by acting as nucleation sites, while still allowing secondary recrystallization to proceed without traditional inhibitor-forming elements at higher concentrations
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
Achieves uniform magnetic properties and reduced iron loss variation along the coil length by controlling oxide particle distribution, enhancing the stability and consistency of magnetic properties.
Implementation Method 1
Control the dispersion of oxide particles containing Ca and/or Mg to 400 or less per unit area in the transverse cross-section, ensuring uniform precipitation
Implementation Method 2
Such a texture is formed by secondary recrystallization, in which crystal grains with the {110} direction, i.e., the Goss orientation, are preferentially grown into giant grains, during a finishing annealing (finish annealing) step
Data Source
AI summary
The present invention provides a grain-oriented electrical steel sheet produced by a method for promoting secondary recrystallization without an inhibitor, the grain-oriented electrical steel sheet including 2.0% or more and 4.5% or less of Si and 0.01% or more and 0.5% or less of Mn on a mass % basis, wherein the number of oxide particles having a diameter of 1 to 3 μm among that (oxide particles) of containing Ca and/or Mg is 400 or less per unit area (1 cm2) in a transverse cross-section perpendicular to a rolling direction. Therefore, the grain-oriented electrical steel sheet has excellent stable magnetic properties throughout the length of a coil.