Tundish control flow method of small square billet continuous casting stopper rod and tundish water gap

Abstract

A tundish control flow method of a small square billet continuous casting stopper rod belongs to the technical field of steel casting. An upper water gap and a middle water gap are closely abutted with each other and arranged in a tundish nozzle pocket brick from top to bottom, wherein a zirconium core is embedded into the middle water gap; a tundish water gap of a lower water gap, which is closely abutted with the middle water gap, is arranged below the tundish nozzle pocket brick, and a zirconium core is also embedded into the lower water gap; a part of the upper part of the tundish nozzle pocket brick, which is matched with the upper water gap, is in a reverse cone cylinder shape, and a part of the lower part of the tundish nozzle pocket brick, which is matched with the middle water gap, is in a cone cylinder shape with a smaller cone angle; center lines of the upper water gap, the middle water gap and the lower water gap are overlapped; the outside diameter of the zirconium core embedded into the middle water gap is larger than that of the zirconium core embedded into the lower water gap, and the inside diameter of the zirconium core embedded into the middle water gap is larger than or equal to that of the zirconium core embedded into the lower water gap; and the tundish control flow is realized by adjusting a spacing between a stopper rod arranged on the upper water gap and the upper water gap and changing the lower water gap. In the invention, integral stopper rod control flow and diameter fixing water gap control flow are organically combined, therefore, the control flow effect is good.

Description

technical field [0001] The invention belongs to the technical field of steel casting, and in particular relates to a tundish flow control method for a billet continuous casting stopper rod and a tundish nozzle. Background technique [0002] The flow control methods of the billet continuous casting tundish include the flow control of the integral stopper rod and the flow control of the sizing nozzle. The overall stopper rod flow control method relies on the stopper rod to open and close in the tundish, and adjusts the flow of molten steel entering the mold by controlling the position from the head of the stopper rod to the nozzle of the tundish. The sizing nozzle flow control method controls the flow of molten steel entering the mold by changing the inner diameter of the nozzle. Both have their own advantages and disadvantages in terms of service life and pulling speed control. In production, different flow control processes can be selected according to the characteristics ...

AI Technical Summary

Problems solved by technology

The overall stopper rod flow control method has the following problems in production: (1) The quality of the nozzle is unstable

Due to the length of the nozzle (330mm height), it is difficult to make the zirconium core of the nozzle. It is assembled in three parts. During use, the zirconium core is prone to fall off, causing the casting speed to drop, and the nozzle suddenly rushes open, causing shutdown accidents such as swelling and breaking.

(2) When producing low-C, low-Si or high-Mn steel series, the corrosion of stopper and nozzle is particularly serious. When the package age is about 25 furnaces, the stopper often loses control suddenly, resulting in unplanned stoppage of production

(3) The protection effect is not good, and the lower end of the tundish nozzle is easy to corrode

After the tundish is used in the middle and later stages, the length of the lower end of the nozzle protruding from the bottom of the tundish is eroded from the original 45mm to within 25mm, so that the submerged nozzle bowl and the tundish nozzle are not tightly connected, affecting the protection effect and reducing the quality of steel products.

(4) Due to the variety of steel types produced and sudden accidents caused by plug rod flow control, planned production cannot be accurately realized. When changing steel types, it will be forced to adjust the composition of molten steel in LF furnaces and converters, resulting in increased steel costs

(5) When the pouring is stopped, due to the irregularity of the stopper rod and nozzle erosion, it is not easy to block the flow, and it is impossible to achieve clean production

However, in actual production, due to melting loss, in order to ensure a certain flow of molten steel, the opening is gradually reduced. When the melting loss is severe, the steel flow cannot be controlled between the stopper rod and the nozzle.

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