Grain-Oriented Electrical Steel Sheet Using Ba and Y Inhibitors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing manufacturing methods for oriented electrical steel sheets using AlN and MnS as grain growth inhibitors require high-temperature reheating, complex purification processes, and result in increased costs and surface defects due to gasification reactions, which deteriorate magnetic properties.
Innovation Solution
The method involves using Ba and Y as grain growth inhibitors, with a composition including Si, C, Al, N, S, and Mn, and employing a manufacturing process that includes hot-rolling, cold-rolling, primary recrystallization annealing, and secondary recrystallization annealing at lower temperatures, without the need for high-temperature purification, thereby stabilizing Goss grains and reducing iron loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AlN and MnS precipitates are used as grain growth inhibitors, then secondary recrystallization can be achieved, but the precipitates must be distributed very finely and uniformly requiring high-temperature heating (1300°C or higher) for long time
Solution Approach 1:
The patent changes the chemical composition parameters by using Ba and Y as grain growth inhibitors instead of conventional AlN and MnS. This substitution allows secondary recrystallization to occur at lower temperatures (below 1300°C) while maintaining the required fine and uniform distribution of precipitates, thus resolving the contradiction between achieving reliable secondary recrystallization and avoiding excessive heating temperatures.
2Manufacturing precision
If high-temperature heating is performed to distribute precipitates uniformly, then fine precipitate distribution is achieved, but slab washing phenomenon occurs due to Fe2SiO4 formation with low melting point
Solution Approach 1:
The patent changes the chemical composition by substituting Ba and Y for conventional AlN and MnS precipitates. This composition change prevents the formation of Fe2SiO4 with low melting point that causes slab washing phenomenon during high-temperature heating, while still achieving uniform fine precipitate distribution necessary for manufacturing precision.
3Manufacturing precision
If purification annealing is performed at high temperature (1200°C) for long time (30 hours or more), then precipitate components are removed, but the manufacturing process becomes complex and cost increases
Solution Approach 1:
The patent changes the chemical composition to use Ba and Y as grain growth inhibitors, which inherently prevent the formation of harmful precipitate components that would require extensive purification annealing. This composition modification eliminates the need for long-duration high-temperature purification processes (30 hours at 1200°C), thereby simplifying the manufacturing process and reducing costs while maintaining manufacturing precision.
4Manufacturing precision
If purification annealing is performed, then precipitates are removed, but Al moves to surface and reacts with oxygen to form Al2O3 oxide that interferes with magnetic domain movement
Solution Approach 1:
The patent changes the chemical composition by using Ba and Y instead of Al-based precipitates. This substitution prevents the formation of Al2O3 surface oxides during purification annealing, as Ba and Y do not exhibit the same surface migration and oxidation behavior as Al. Consequently, magnetic domain movement is not interfered with, while still achieving effective precipitate removal and purification.
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 oriented electrical steel sheets with improved magnetic characteristics and reduced iron loss, lower manufacturing costs, and eliminates surface defects, while avoiding the need for high-temperature reheating and purification processes.
Implementation Method 1
Ba, Y or a composite of Ba and Y which are segregated at grain boundaries
Implementation Method 2
abnormal grain growth corresponding to secondary recrystallization must be formed
Implementation Method 3
a Goss texture of a {110} orientation should strongly develop in a rolling direction thereof
Implementation Method 4
The abnormal grain growth occurs when normal grain growth is inhibited by precipitates, inclusions, or elements that are solidified or segregated
Data Source
AI summary
An oriented electrical steel sheet includes Ba at about 0.005 wt % to about 0.5 wt % inclusive, Y at about 0.005 wt % to about 0.5 wt % inclusive, or a composite of Ba and Y at about 0.005 wt % to about 0.5 wt % inclusive, the remainder including Fe and impurities, based on 100 wt % of a total composition of a base steel sheet thereof.