High-Silicon Steel Sheet Composition for Crack-Resistant Rolling
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Solution Overview
Problem
High-silicon steel sheets with silicon content greater than 4% are difficult to manufacture using conventional rolling processes due to reduced workability and susceptibility to cracking, as existing methods either require toxic chemicals or do not adequately improve magnetic flux density and core loss characteristics.
Innovation Solution
A soft high-silicon steel sheet composition including silicon (Si) greater than 4% to 7%, chromium (Cr) 1% to 20%, and boron (B) 0.01% to 0.05%, with optional total aluminum (Al) 0.1% to 3%, and controlled microstructural grains, manufactured through hot rolling followed by cold rolling at specific temperature ranges to suppress ordered phases and enhance workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon content is increased to improve magnetic flux density and reduce core loss, then magnetic properties are improved, but workability and manufacturability deteriorate due to reduced ductility and increased cracking susceptibility
Solution Approach 1:
The patent changes the chemical composition parameters by adding specific alloying elements (Ti: 0.01-0.06 wt%, Nb: 0.01-0.06 wt%, V: 0.01-0.06 wt%, Al: 0.01-0.05 wt%, B: 0.003-0.03 wt%) to the high-silicon steel composition. These parameter changes modify the material properties to maintain ductility and workability while preserving the high silicon content (4-7 wt%) needed for superior magnetic properties
Solution Approach 2:
The patent creates a composite material system by combining high-silicon steel with multiple alloying elements (Ti, Nb, V, Al, B). This composite approach allows the material to exhibit both the high magnetic flux density characteristics of high-silicon steel and the improved workability provided by the synergistic effects of the added elements
2Loss of energy
If silicon content is increased beyond 4% to maximize magnetic properties, then core loss is reduced, but the steel sheet becomes difficult to manufacture through conventional cold rolling processes
Solution Approach 1:
The patent modifies the compositional parameters by introducing microalloying elements (Ti, Nb, V) in controlled amounts. These parameter changes prevent excessive grain growth and maintain material ductility, enabling conventional cold rolling processes to successfully manufacture high-silicon steel sheets with 4-7 wt% silicon content while achieving low core loss
Solution Approach 2:
The patent applies local quality by strategically adding specific alloying elements in precise amounts to achieve localized effects: Ti, Nb, and V control grain structure and prevent brittleness, Al deoxidizes and refines the structure, and B strengthens grain boundaries. This localized compositional optimization enables manufacturability while maintaining high magnetic performance
3Productivity
If conventional cold rolling process is used to manufacture high-silicon steel sheets, then production efficiency is maintained, but crack formation increases due to reduced ductility
Solution Approach 1:
The patent changes the compositional parameters by adding Ti (0.01-0.06 wt%), Nb (0.01-0.06 wt%), and V (0.01-0.06 wt%) which form fine precipitates that strengthen the matrix without compromising ductility. This allows conventional cold rolling to proceed at normal production speeds while the enhanced material integrity prevents crack formation during processing
Solution Approach 2:
The patent applies beforehand cushioning by pre-addiction of alloying elements (Ti, Nb, V, Al, B) to the steel composition before rolling. These elements prepare the material structure in advance to resist cracking during the cold rolling process, cushioning against the inherent brittleness of high-silicon steel while maintaining production efficiency
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 solution enables the production of high-silicon steel sheets with improved magnetic flux density, reduced core loss, and enhanced workability without the need for additional siliconizing processes, allowing for commercial production of thin sheets with high production rates and reduced crack formation.
Implementation Method 1
it has become known that, in order to prevent the formation of ordered phases in a steel sheet, chromium (Cr) in an amount of 1 wt % or more is added to a steel sheet
Implementation Method 2
in order to improve the rollability of a steel sheet, boron (B) in an amount of 0.01 wt % to 0.05 wt % is added to a steel sheet
Implementation Method 3
a soft high-silicon steel sheet may be manufactured by a manufacturing process similar to a manufacturing process for manufacturing electrical steel sheets having a relatively low silicon content, for example, within the range of 4% or less or 3.5% or less
Implementation Method 4
a soft high-silicon steel sheet may be manufactured by a manufacturing process similar to a manufacturing process for manufacturing electrical steel sheets having a relatively low silicon content
Data Source
AI summary
The present invention relates to a soft high-silicon steel sheet, and more particularly, to a soft high-silicon steel sheet which has ductility even if the silicon content thereof is greater than 4%, and can thus be manufactured into a steel sheet having a high silicon content only by means of rolling without an additional siliconizing process. The soft high-silicon steel sheet may include a silicon content greater than 4 wt % and less than or equal to 7 wt % and 1 to 20% of chromium, or may include 5 to 7 wt % of Si+Al and 1 to 20 wt % of chromium.