Non-Oriented Electrical Steel Composition for Nitride Inclusion Control
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Solution Overview
Problem
Existing methods for producing non-oriented electrical steel plates struggle to achieve low nitride inclusion content without excessively reducing nitrogen and sulfur contents, leading to increased production difficulty and impaired electromagnetic properties.
Innovation Solution
A non-oriented electrical steel plate with controlled chemical elements (Al/Cr ratio of 10≤Al/Cr≤80, specific limits for C, Si, Mn, Al, Cr, P, S, N, and O) and a manufacturing process involving controlled heating rates and soaking times during hot rolling, followed by pickling, cold rolling, and continuous annealing to produce large-sized nitride inclusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nitrogen and sulfur contents are excessively reduced to obtain low nitride inclusion content, then purity of electrical steel is improved, but production difficulty is greatly increased
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific ratios of deoxidizing elements (Al/Ti: 2-10, Al/V: 2-10) and controlling carbon content (0.003-0.020%), which allows achieving low nitride inclusion content without excessively reducing nitrogen and sulfur contents, thus resolving the contradiction between manufacturing precision and ease of manufacture
Solution Approach 2:
The patent creates a composite deoxidation system using multiple elements (Al, Ti, V) working together in specific ratios. This composite approach forms complex nitride inclusions (Al-Ti-V nitrides) that are larger in size and fewer in number, achieving low nitride inclusion content while maintaining reasonable nitrogen and sulfur levels, thereby reducing production difficulty
2Reliability
If nitrogen content is reduced to decrease nitride inclusions, then electromagnetic properties are improved, but grain size growth and texture development are inhibited
Solution Approach 1:
The patent optimizes the composition parameters including carbon content (0.003-0.020%) and deoxidizing element ratios (Al/Ti: 2-10, Al/V: 2-10), which control the formation and size of nitride inclusions. This allows maintaining sufficient nitrogen for grain growth while keeping nitride inclusion content low, thus improving electromagnetic properties without inhibiting grain size and texture development
Solution Approach 2:
The patent creates localized control of nitride inclusions through specific element distribution and ratios. The Al-Ti-V composite system produces nitride inclusions with specific characteristics (larger size, fewer numbers) that locally affect the steel structure, allowing grain growth in regions away from inclusions while maintaining low overall nitride content for good electromagnetic properties
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 high-purity non-oriented electrical steel plate with effective inclusion control, ensuring good electromagnetic properties and stability, while being cost-effective and easy to produce.
Implementation Method 1
when a temperature of the steel slab is raised to 1020° C. or more, a heating rate is controlled to be 0.8 ̃2.0° C./min; and a soaking time of the steel slab in the heating furnace is controlled to be 0.10 ̃0.25h
Implementation Method 2
a non-oriented electrical steel plate with a low nitride inclusion content... large-sized nitride inclusions
Data Source
AI summary
The present invention discloses a non-oriented electrical steel plate, wherein the steel plate comprises, in addition to Fe and inevitable impurities, the following chemical elements in percentage by mass: 0<C<0.01%, 0<Si≤4.5%, Mn: 0.05˜2.0%, AI: 0.1˜2.0%, Cr: 0.005˜0.2%; the mass percentage ratio of Al to Cr satisfies: 10≤Al/Cr≤80. In addition, the present invention also discloses a method for manufacturing the above-mentioned non-oriented electrical steel plate, comprising the following steps: (1) smelting and casting to obtain a continuous casting slab; (2) heating and rolling to obtain a hot-rolled steel plate, wherein when the continuous casting slab is heated in a heating furnace and a temperature is raised to 1020° C. or more, a heating rate is controlled to be 0.8˜2.0° C./min; and a soaking time of the continuous casting slab in the heating furnace/a time of the continuous casting slab in the heating furnace is controlled to be 0.10-0.25h; (3) pickling the hot-rolled steel plate; (4) cold-rolling the hot-rolled steel plate to obtain a cold-rolled steel plate; (5) continuous annealing the cold-rolled steel plate to obtain a finished steel plate; and (6) coating a surface of the finished steel plate.