Non-Oriented Electrical Steel Sheet for {100} Grain Development
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Solution Overview
Problem
Non-oriented electrical steel sheets face challenges in achieving uniform magnetic characteristics across all directions due to difficulties in developing {100} crystal grains, which are typically difficult to grow, leading to issues in winding and manufacturing processes.
Innovation Solution
A non-oriented electrical steel sheet with a specific chemical composition and controlled manufacturing process, including α-γ transformation, refined crystal structure through hot rolling, and controlled intermediate annealing to promote {100} crystal grain development, ensuring a recrystallization rate of 1% to 99% and appropriate thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If {100} crystal grains are developed using phase transformation, then magnetic characteristics are improved, but sheet thickness must be increased to approximately 4 mm which causes winding difficulties
Solution Approach 1:
The invention changes the chemical composition parameters (adding specific elements like Al, Ti, V, Nb, Ta in controlled amounts) and process parameters (intermediate annealing temperature, cold rolling reduction ratio) to achieve {100} crystal grain development while maintaining thin sheet thickness of 0.5 mm or less, thus resolving the contradiction between magnetic characteristics and sheet thickness
Solution Approach 2:
The invention uses composite alloying with multiple elements (Al, Ti, V, Nb, Ta, Mn, Si) that work synergistically to control phase transformation behavior and crystal grain development, enabling simultaneous achievement of excellent magnetic characteristics and thin sheet thickness that would not be possible with single-element additions
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 excellent magnetic characteristics across all directions, facilitating the production of high-performance motor cores with reduced iron loss and improved punching workability.
Implementation Method 1
a chemical composition of an α-γ transformation is presupposed, the crystal structure is refined by transformation from austenite to ferrite during hot rolling
Implementation Method 2
the temperature of intermediate annealing is controlled to be within a predetermined range to cause overhanging recrystallization (hereinafter, bulging)
Data Source
AI summary
What is provided is a non-oriented electrical steel sheet having a chemical composition in which, by mass%, C: 0.010% or less, Si: 1.50% to 4.00%, sol. Al: 0.0001% to 1.0%, S: 0.010% or less, N: 0.010% or less and one or a plurality of elements selected from the group consisting of Mn, Ni, Co, Pt, Pb, Cu and Au: 2.50% to 5.00% in total with a remainder including Fe and impurities, in which a recrystallization rate is 1% to 99% in a metallographic structure, a sheet thickness is 0.50 mm or less, and, in the case of measuring a magnetic flux density B50 after annealing the non-oriented electrical steel sheet at 800°C for two hours, a magnetic flux density B50 in a 45° direction with respect to a rolling direction is 1.75 T or more.