Non-oriented steel sheet anisotropy reduction via {411} orientation
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Solution Overview
Problem
Non-oriented electromagnetic steel sheets face challenges in achieving uniform magnetic characteristics in all directions due to anisotropy issues, particularly in 45° directions relative to the rolling direction, and segregation of elements like Mn can cause cracking during cold rolling.
Innovation Solution
A non-oriented electromagnetic steel sheet with optimized chemical composition and controlled crystal orientations, including specific ranges for elements such as C, Si, Mn, Cu, and Ni, and controlled transformation temperatures, combined with hot rolling and annealing processes to enhance {411} crystal orientation, reducing anisotropy and ensuring excellent magnetic characteristics in 45° directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Mn content is increased to promote γ→α phase transformation and accumulate strain in γ-phases, then magnetic characteristics are improved, but segregation occurs at sheet thickness center parts causing cracking in cold rolling
Solution Approach 1:
The patent optimizes the Mn content parameter to a specific range (0.10-2.50%) and combines it with controlled amounts of Ni and Cu to achieve the desired γ→α phase transformation behavior without excessive segregation. This parameter optimization resolves the contradiction by finding the optimal balance point where magnetic characteristics are improved while avoiding cold rolling cracking.
Solution Approach 2:
The patent creates a composite alloying strategy by combining Mn with Ni and Cu in specific proportions. This composite approach allows the synergistic effects of multiple elements to promote γ→α phase transformation and accumulate strain in γ-phases while the combined composition prevents excessive segregation and cracking during cold rolling.
2Reliability
If {100} crystal orientations are developed through γ→α phase transformation techniques, then magnetic characteristics in certain directions are improved, but in-plane anisotropy increases
Solution Approach 1:
The patent promotes the development of {411} crystal orientations specifically, which have different anisotropy characteristics compared to conventional {100} orientations. By targeting this specific local crystal orientation quality, the patent achieves improved magnetic characteristics while reducing in-plane anisotropy, as {411} orientations provide more uniform magnetic properties across different directions in the sheet plane.
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 results in a steel sheet with suppressed rollability issues and optimized magnetic characteristics, achieving magnetic flux densities of 1.58 T or more in the rolling direction and 1.70 T or more in the 45° direction, while minimizing iron loss and anisotropy.
Implementation Method 1
studies about component systems in which γ→α phase transformation occurs have been variously made
Implementation Method 2
a transformation temperature Ar3 (°C) defined by the following Formula (1) is from 750 to 1050°C
Data Source
AI summary
To provide a non-oriented electromagnetic steel sheet containing, in percentage by mass, predetermined elements, in which the steel sheet has a metal structure having a transformation temperature Ar3 (°C) of from 750 to 1050°C and a recrystallization ratio of from 1% to 99%, a sheet thickness is 0.50 mm or less, and Sac > 0.120, Sac > Sbc > Sag, and 0.050 > Sag are satisfied in a case in which an area ratio of a {411} crystal grain and an area ratio of a {110} crystal grain in any cross section are defined as Sac and Sag respectively and an area ratio occupied by a {411} crystal grain in a region up to 20% from the higher KAM value side is defined as Sbc.