Oriented high silicon steel strip and efficient annealing-mode preparation method thereof

Abstract

An oriented high silicon steel strip and an efficient annealing-mode preparation method thereof belong to the technical field of metallurgy. The oriented high silicon steel strip comprises the following ingredients (by weight): 4.5-7.0% of Si, C being less than or equal to 0.1%, 0.005-0.05% of Als, 0.003-0.01% of N, 0.03-0.3% of Mn, Cu being less than or equal to 0.5%, 0.003-0.035% of S, 0.02-0.4%of Nb, 0.005-0.1% of V, and the balance Fe and impurities. The method comprises the following steps: casting according to the composition design to obtain a slab, hot-rolling, carrying out acid pickling, cold-rolling after acid pickling, carrying out decarburizing annealing on the slab, carrying out nitriding treatment, and finally carrying out secondary recrystallization annealing. By controlling an inhibitor system, the rolling technology and the annealing technology, short-process annealing-mode preparation of the oriented high silicon steel is realized, production efficiency is raised, production cost is reduced, and the product has excellent comprehensive performance and is thinner in thickness.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a preparation method of an oriented high-silicon steel strip and a high-efficiency annealing mode thereof. Background technique [0002] Oriented silicon steel is mainly used in the iron core of power electronic devices such as transformers and ballasts, and is characterized by high magnetic induction along the rolling direction of the steel plate. High-silicon steel generally refers to iron-silicon alloys with a Si content greater than 4.5wt%. As the Si content increases, the magnetic permeability of oriented high-silicon steel increases, and the electrical conductivity and magnetostriction coefficient decrease, especially when the Si content is 6.5wt%. The hysteresis expansion coefficient tends to zero, so the grain-oriented high-silicon steel has significant advantages of low iron loss and low noise at high frequencies. Therefore, oriented high-silicon steel ha...

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Problems solved by technology

[0004] Japanese patents (Shao 63-069917, 63-089622) have obtained oriented high-silicon steel strips with a thickness of 0.2-0.3 mm by means of hot rolling-warm rolling-cold rolling, using MnS, AIN, TiC or VC as inhibitors, B 8 =1.65T,P 10 / 50 ≈0.15W / kg; Japanese patents (Ping 4-080321, 224625, 362134) adopt low-temperature heating AlN scheme and later nitriding treatment method, magnetic performance B 8 =1.62~1.67T; Chinese patent (CN104911322 A) also uses nitriding treatment to add inhibitors to enhance the inhibitory force, magnetic performance B 8 =1.55~1.61T; Chinese patent (CN104372238 A) uses a special thin strip continuous casting process to optimize structure-texture-inhibitor, but there are problems such as unstable cast strip quality, serious surface oxidation of cast strip, and complicated equipment maintenance

[0005] The above secondary recrystallization annealing process for oriented high-silicon steel adopts the traditional slow heating and coiling process, which has the following problems: ①The temperature difference between the inside and outside of the coiled annealing steel ring is large, and the secondary recrystallization is uneven; ②The annealing cycle is as long as dozens Hours, high energy consumption and high preparation cost; ③ cannot dynamically monitor product performance during the secondary recrystallization process, etc.

Although Terni Company (US.6488784B1) increased the silicon content to 5.5wt.%, it is still mainly aimed at ordinary grain-oriented silicon steel with a Si content of ~3.2wt.%, which has the following problems: ①The inhibition is mainly strengthened by nitriding treatment , the primary recrystallized grain size is very sensitive to temperature and the short-term nitriding treatment and continuous annealing lead to uneven diffusion of N atoms, so the final magnetic properties are very sensitive to the nitriding process; ②The preparation process is limited to thickness specifications above 0.23mm The product

[0007] Compared with ordinary grain-oriented silicon steel, grain-oriented high-silicon steel has problems such as insufficient precipitation of traditional inherent inhibitors (MnS, MnSe, AlN, etc.) and limited addition of grain boundary segregation elements (such as Sn and Sb, etc.), resulting in microstructure- The matching of texture-inhibitor is more difficult, and there is no report on the preparation of grain-oriented high-silicon steel by short-flow annealing process

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