JPS63264256A - Flow rate control device for continuous casting - Google Patents

Abstract

PURPOSE:To make the direct contacting area with molten steel small and to prevent impossibility of sliding caused by sticking of the molten steel, etc., by fitting a valve for flow rate control rod in the molten steel flowing hole of a nozzle and executing opening/closing of the valve and a flowing inlet by rotating the flow rate control rod. CONSTITUTION:An extension part 12 projecting in the tundish 22 is arranged at the upper end part of the nozzle 10 and the tip of the extension part 12 becomes flat as the horizontal sliding face 11. At the wall part of the extension part 12, the flowing inlet 13 communicating to the molten metal flowing hole 14 is arranged. In the upper part of the nozzle 10, the flow rate control rod 16 having the valve 20 projecting to the horizontal sliding face 18 and core part 19 at outer edge of shoulder part 17 is fitted. The valve 20 of the flow rate control tod 16 is projected below the opening position of the flowing inlet 13 in the nozzle 10 and by providing a cutout part 21 at a part thereof, the opening/closing of the flowing inlet 13 is controlled by rotating the flow rate control rod 16. Then, the molten steel in a tundish 22 is supplied into a mold 23 from the flowing inlet 13 and the molten steel flowing hole 14 through a discharging hole 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a flow rate control device for continuous casting that can prevent outside air from being drawn in and accurately control the flow rate.

(Prior technology) Conventional flow rate control devices for continuous casting include: ■ An open nozzle type that is often used in billet continuous casting machines and controls the flow rate only by the nozzle diameter; and ■ A stopper at the top of the nozzle. , a nozzle stopper type that controls the flow rate by opening and closing the fitting of the nozzle stopper, and a slide valve type that controls the flow rate by opening and closing each outlet of a fixed plate and a slide plate, each of which has been adopted to take advantage of its advantages. There is. However, these methods also had the following drawbacks. That is, with the open nozzle method (■), the initial flow rate cannot be obtained if the nozzle diameter expands due to melting damage or is blocked by nonmetallic inclusions in the steel. Accurate flow control becomes difficult if the mating surface of is eroded, and the flow rate may become uncontrollable depending on the blockage phenomenon of non-metallic inclusions.
Even if the diameter of the refractory increases due to melting, the flow rate can be controlled accurately by opening and closing operations, but since the device is located outside the tundish and the structure has many sliding surfaces or joints in the refractory, outside air may be drawn in. It was easy to clean and was inferior to cleaning steel. Therefore, in order to compensate for these drawbacks, it has been awaited to develop a flow rate control device for continuous casting that can prevent outside air from being drawn in and accurately control the flow rate. Conventionally, a method has been proposed in Japanese Patent Application Laid-open No. 182857/1983 with this aim in mind. This system has an extension at the top of the nozzle that projects into the tundish, and a flow control port is opened in the side wall of this extension. The flow rate is controlled in combination with a sliding control tool that opens and closes this opening by moving it up and down.

In addition, in the same spirit, there is a dome nozzle in which the upper end surface has a convex spherical inner surface and an opening communicating with the nozzle's flow hole is provided on that surface, and the lower end surface corresponds to the convex spherical inner surface of the upper end surface of the dome nozzle. It has a concave spherical surface, and consists of a rotary with an opening that penetrates this surface and the side wall.The rotation of this rotor, that is, the sliding of the uneven surface, controls the flow rate by opening and closing the opening of the rotor and the opening of the nozzle. A rotary valve system is known.

(Problems to be Solved by the Invention) Among these conventional systems, the flow rate control device disclosed in Japanese Patent Application Laid-Open No. 182857/1983 slides inside the nozzle molten metal flow hole when opening and closing the extension opening at the top of the nozzle. This is done by vertical movement of the rod-shaped body or the sliding outer cylinder that surrounds the nozzle extension, but in both cases, most of the sliding surface of the rod-shaped body or the outer cylinder, which is the nozzle and sliding control device, is moved up and down. is exposed to contact with molten steel. As a result, molten steel or non-metallic inclusions tend to adhere, and once they have adhered, they may become unable to slide.

On the other hand, in a rotary valve type flow control device, the rotor must be thoroughly suppressed and supported on the sliding surface between the rotor and the dome nozzle.In other words, if the rotor moves even slightly upward, it will immediately affect the entire sliding surface. Molten steel infiltrated the structure, making it impossible to slide. It is an object of the present invention to provide a flow rate control device for continuous casting that can eliminate the above-mentioned conventional problems, prevent outside air from being drawn in, and accurately control the flow rate.

(Means for Solving the Problems) In order to achieve this object, the present invention has the following configuration. This inventive device will be explained below with reference to drawings and embodiments.

First, reference numeral 10 denotes a nozzle (in this drawing, a mold submerged nozzle is shown as an example, but a tundish nozzle with a submerged nozzle at the bottom also falls under the scope of the present invention).

), and a tundish 22 is provided at the upper end of the nozzle 10.
An inwardly protruding extension 12 is provided, the extension 12
The tip is flat as a horizontal sliding surface 11. Further, an inlet 13 communicating with the molten steel flow hole 14 is provided in the wall of the extension 12 . Note that 15 is a discharge port at the lower end of the nozzle 10. A shoulder portion 17 is provided at the top of the nozzle 10.
A flow control rod 16 having a horizontal sliding surface 18 and a valve 20 protruding from a core 19 is fitted to the outer edge of the rod. At this time, the horizontal sliding surface 11 of the nozzle 10 and the horizontal sliding surface 18 of the flow control rod 16 have a corresponding sliding relationship, and the valve 20 of the flow control rod 16 is located at the opening position of the inlet 13 of the nozzle 10. By protruding as far as below and providing a notch 21 in a part, gJ closing of the inlet 13 is controlled by rotation of the flow rate control rod 16, and the molten steel M in the tundish 22 is transferred to the inlet 13. Molten steel is supplied from the flow hole 14 to the mold 23 through the discharge port 15.

(Effects of the Invention) Due to the above-described configuration, the present invention provides the following effects.

(1) When opening and closing the valve of the flow control rod and the inlet of the nozzle, the area that comes into direct contact with molten steel is extremely small, which eliminates the problem of inability to slide due to adhesion of molten steel or nonmetallic inclusions.

(2) There are few joints between refractories that have many opportunities for outside air to be drawn in, and especially the sliding surfaces are inside the tundish, so it is possible to prevent outside air from being drawn in.

(3) The diameter of the inlet or the shape and size of the valve notch can be freely selected. Furthermore, even if the diameter of the inlet port is enlarged due to melting damage, a desired inflow area can be secured by overlapping the valve and the inlet port depending on the degree of rotation of the valve section, that is, by squeezing injection method, and accurate flow rate control can be achieved.

[Brief explanation of drawings]

The drawings show an embodiment of the device according to the present invention, and FIG. 1 is a vertical cross-sectional view showing a state in which the notch of the valve is open and communicates with the inlet, FIG. 2 is a cross-sectional plan view of the same, and FIG. The figure is a longitudinal cross-sectional view of the main part with the inlet closed by a valve, and FIG. 4 is a cross-sectional plan view of the same. 10... Nozzle, 11... Horizontal sliding surface, 12...
Extension part, 13... Inflow port, 14... Molten steel distribution hole, 1
5...Discharge port, 16...Flow rate control rod, 17...
・Shoulder part, 18... Horizontal sliding surface, 19... Core part, 20
... Valve, 21 ... Notch, 22 ... Tundish, 23 ... Mold 1M ... Molten steel, Fig. 1 Fig. 2 Z Fig. 3 Fig. 40

Claims (1)

[Claims] The nozzle 10 has an extension part 12 protruding into the tundish 22 and has a horizontal sliding surface 11 at its tip, an inlet 13 communicating with a molten steel flow hole 14 on the side wall, and a shoulder part 17 as a tip fitting part. The flow control rod 16 has a horizontal sliding surface 18 on its outer edge and a valve 20 on its core 19 that protrudes into the molten steel flow hole 14 of the nozzle 10.
is fitted into a molten steel flow hole 14 of a nozzle 10, and a flow control device for continuous casting supplies molten steel M from a tundish 22 to a mold 23 by opening and closing a valve 20 and an inlet 13 by rotating a flow rate control rod 16.