High grade non-oriented silicon steel produced by continuous casting and rolling of sheet billet and production method thereof

Abstract

High grade non-oriented silicon steel produced by continuous casting and rolling of sheet billet comprises the following components, by weight: no more than 0.003% of C, 2.20-3.20% of Si, 0.25-1% of Al, no more than 0.002% of S, no more than 0.002% of N, no more than 0.02% of Cu, 0.20-0.50% of Mn, and the balance of Fe and unavoidable impurities; besides, contents of the components satisfy the following relations: Si+Al<=4.2%, [Al]*[N]: 5+10<-8>-1.5*10<-7>, and [Mn]*[S]: 2*10 <-8>-1*10<-7>. The manufacture method comprises the steps of: smelting and vacuum treatment; continuous casting with liquid core reduction; billet heating; hot continuous rolling; flattening; normalizing treatment; conventional acid pickling; cold rolling; and finished product annealing. The steel plate provided by the invention has advantages of good surface quality, low iron loss, excellent magnetic, and no corrugated defects.

Description

technical field [0001] The invention relates to non-oriented silicon steel and a manufacturing method thereof, in particular to high-grade non-oriented silicon steel produced by continuous casting and rolling of thin slabs and a manufacturing method thereof. Background technique [0002] High-grade non-oriented silicon steel is used as the iron core material of large motors or high-efficiency motors, and its iron loss and surface quality affect the loss and efficiency of the motor. In the production of high-grade non-oriented silicon steel by traditional long-flow process, the temperature drop in the hot rolling process is large, rolling is difficult, the control of hot-rolled plate shape is difficult, and the yield is low. The high-grade non-oriented silicon steel produced by thin slab continuous casting and rolling has a small temperature drop during the process, which can realize high-temperature rolling and obtain hot-rolled steel strips with good shape. However, high-g...

AI Technical Summary

Problems solved by technology

The C content is high, and the recrystallization process of the finished product must be decarburized for a long time, which affects the running speed of the steel strip, reduces the production efficiency, and increases the production cost.

In addition, the oxidizing atmosphere in the decarburization process causes the oxide layer in the steel strip to thicken and the iron loss increases

[0005] 2. Increase the equiaxed crystal ratio of the slab by adding electromagnetic stirring equipment to solve the problem of corrugated defects in the finished steel strip. Due to the narrow section of the slab produced in thin slab continuous casting and rolling, the cooling speed is fast, and the electromagnetic stirring is equivalent. The effect of increasing the axial crystal ratio is not good

[0006] 3. Corrugated defects can be reduced and eliminated by adopting secondary cold rolling and secondary annealing, resulting in a great increase in cost, which cannot reflect the cost advantage of thin slab continuous casting and rolling

However, there is no solution to the corrugated defects of high-grade non-oriented silicon steel produced by thin slab continuous casting and rolling

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