Method for producing high-magnetic-induction oriented silicon steel by continuous casting and rolling of thin slab

Abstract

The invention relates to a method for producing high-magnetic-induction oriented silicon steel by continuous casting and rolling of a thin slab. The method comprises the following steps of: smelting and performing continuous casting and rolling of the thin slab; dephosphorizing the casting blank by using high-pressure water for the first time; performing soaking; dephosphorizing for the second time; performing finish rolling; normalizing and then cooling to below 100 DEG C; performing cold rolling to reach the thickness of finished products; continuously decarburizing and annealing; permeating N2; coating a magnesium oxide parting agent and annealing at high temperature; and stretching flatly and coating an insulating layer. By the method, manufacturing cost is low; the defects that the surface of a steel plate is mixed with impurities and overlapped with skin and the like can be overcome; magnetic performance is stable; and the continuous casting process is loose.

Description

technical field [0001] The invention relates to a production method of an oriented silicon steel plate, in particular to a method for producing a high magnetic induction oriented silicon steel by a thin slab continuous casting and rolling process. Background technique [0002] Generally, the main production process of oriented silicon steel is as follows: molten steel is continuously cast or die-cast to form a billet, and the billet is reheated and then hot-rolled. High-temperature annealing, stretching, leveling annealing and insulating coating to obtain the finished product. [0003] In the production of grain-oriented silicon steel, the so-called secondary recrystallization principle is used. The so-called secondary recrystallization means that under certain conditions, some grains annex the surrounding grains and grow into very large grains. The secondary recrystallization of grain-oriented silicon steel occurs during the high-temperature annealing process, and the gra...

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Problems solved by technology

[0007] 1) The heating furnace has high energy consumption, shortened life, and low output: due to the high heating temperature, the fuel consumption of the heating furnace is large

Moreover, due to the long-term high-temperature thermal load, the lining refractory material in the high-temperature zone of the heating furnace is seriously peeled off, and the service life is shortened, which increases the maintenance cost

Due to the formation of 2FeO~SiO on the surface of the slab 2 Oxide and other oxides, the melting point of the oxide layer is low, the oxide layer melts in the high-temperature heating furnace and flows to the bottom of the furnace, requiring a lot of manpower and material resources to clean the slag, the working conditions of the furnace repair are extremely poor, and the operating rate of the heating furnace is greatly reduced

[0008] 2) Low yield: due to the high heating temperature of the casting slab, the burning loss increases; and the coarsening of the casting slab grains and the oxidation of the grain boundary at the edge, the hot-rolled sheet is prone to edge cracking, and a large amount of edge trimming is required in the subsequent process. The overall yield is reduced and the manufacturing cost is increased;

[0009] 3) Instable magnetic properties: It is difficult to ensure the final rolling temperature at the end of the slab during the hot rolling process, which makes the distribution of the inhibitor uneven, resulting in magnetic fluctuations of the steel coil; due to the coarsening of the slab grains, the product is prone to linear thin crystal, also degrades the magnetic properties

The main disadvantage of this patent is that the slab soaking time is too long, which takes more than two hours. In actual large-scale production, the buffer time of the tunnel furnace (soaking furnace) for continuous casting and rolling of thin slabs is limited, and it is difficult to meet the requirements of long-term soaking. hot request

[0022] In addition, in the thin slab continuous casting and rolling process, the continuous casting machine and the rolling mill are rigidly connected. , it is very easy to form inclusions, heavy skin and other defects on the surface of the hot-rolled plate, and finally inherit it to the finished product. Therefore, compared with the conventional thick slab continuous casting, the surface quality of the finished product of the thin slab continuous casting and rolling process is poor, and there is no market competition This also restricts thin slab continuous casting and rolling to produce high-end products

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