Grain-Oriented Electrical Steel Sheet Sulfurization for Core Loss Reduction
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Solution Overview
Problem
Conventional grain-oriented electrical steel sheet production methods require high-temperature slab heating, leading to high manufacturing costs and inadequate magnetic properties, with the inhibitorless method struggling to achieve sufficient magnetic stability and transformer core loss reduction.
Innovation Solution
A sulfurization method is developed to enhance secondary recrystallization by increasing sulfur in the steel substrate, optimizing material components, and using a specific annealing process to improve magnetic properties and reduce transformer core loss without high-temperature slab heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature slab heating exceeding 1300°C is used to dissolve inhibitor components, then secondary recrystallization can be developed, but manufacturing cost increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters by precisely controlling S, Se, and O content within specific ranges (S: 0.003-0.030%, Se: 0.003-0.030%, O: 0.003-0.030%). This compositional optimization enables secondary recrystallization to occur at lower temperatures without requiring excessive slab heating above 1300°C, thereby reducing manufacturing costs while maintaining reliable texture development
Solution Approach 2:
The patent creates a composite chemical composition system by combining multiple trace elements (S, Se, O, Al, Mn, Si, C, N, P, Sb) in specific proportions. This composite approach allows the steel to achieve optimal grain boundary characteristics that facilitate secondary recrystallization at reduced temperatures, eliminating the need for high-cost excessive heating while ensuring reliable texture formation
2Ease of manufacture
If inhibitorless method is used to reduce manufacturing cost, then high-temperature slab heating is eliminated, but magnetic property and stability become insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing specific ranges of S, Se, and O content (each 0.003-0.030%), which act as controlled impurities to pin grain boundaries and enable stable secondary recrystallization. This parameter optimization allows the inhibitorless method to achieve both cost reduction and magnetic property stability by creating optimal grain boundary conditions without traditional inhibitor components
Solution Approach 2:
The patent applies local quality control by precisely managing trace element distribution at grain boundaries. The controlled presence of S, Se, and O creates localized grain boundary characteristics that differ from the bulk material, providing pinning effects that stabilize secondary recrystallization and ensure magnetic property stability while maintaining the overall inhibitorless composition
3Reliability
If sulfur content is increased to enhance secondary recrystallization, then magnetic property improves, but transformer core loss increases due to oxidation
Solution Approach 1:
The patent optimizes the sulfur content parameter within a specific range (0.003-0.030%) rather than using excessive amounts. This controlled parameter change achieves the desired grain boundary pinning effect for stable secondary recrystallization and good magnetic properties while minimizing oxidation-related energy losses. The balanced composition prevents both insufficient and excessive sulfur effects
Solution Approach 2:
The patent creates a composite chemical system combining S, Se, and O in specific proportions, where each element contributes to grain boundary characteristics. This composite approach distributes the functional requirements among multiple elements, achieving effective grain boundary pinning for magnetic property enhancement while the balanced composition minimizes oxidation tendencies that would increase transformer core loss
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 method stabilizes secondary recrystallization, enhances magnetic properties, and effectively reduces transformer core loss, achieving low-cost production of grain-oriented electrical steel sheets with improved magnetic performance and reduced strain-related issues.
Implementation Method 1
by diffusing S into the steel substrate with a heating rate of 30 °C/h or less under an atmosphere of any of N2, Ar, and mixed gas thereof
Implementation Method 2
such texture is formed through secondary recrystallization of preferentially causing the growth of giant crystal grains in (110)[001] orientation which is called Goss orientation
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A grain-oriented electrical steel sheet having a composition containing, in mass%, C: 0.005% or less, Si: 2.0% to 4.5%, and Mn: 0.5% or less, and also containing Sb and P in respective ranges satisfying 0.01% ≤ [%Sb] ≤ 0.20% and 0.02% ≤ [%P] ≤ 2.0 × [%Sb], with a balance being Fe and incidental impurities, wherein when the steel sheet is excited to 1.0 T at 50 Hz in a rolling transverse direction, a magnetizing force (TD-H10) and an iron loss (TD-W10) are respectively (TD-H10) ≥ 200 A/m and (TD-W10) ≥ 1.60 W/kg. Thus, a grain-oriented electrical steel sheet having excellent transformer core loss can be obtained industrially stably at low cost.