EP-4737029-A1 - UPPER-NOZZLE/UPPER-PLATE INTEGRATED OBJECT

Abstract

Provided is a combination upper nozzle and upper plate capable of preventing alumina in molten steel from adhering to a lower portion of an upper nozzle where the alumina adheres heavily. A combination upper nozzle and upper plate (1) used for a slide gate, the combination upper nozzle and upper plate (1) including gas blowing portions (21 and 22) in two places, in which one gas blowing portion (21) is capable of blowing a gas to at least an upper portion of an upper nozzle (1-1), and the other gas blowing portion (22) is capable of blowing the gas simultaneously to a lower portion of the upper nozzle (1-1) and a sliding surface of an upper plate (1-2).

Inventors

• HATTANDA, HIROKATSU

Assignees

• Tokyo Yogyo Kabushiki Kaisha

Dates

Publication Date

20260506

Application Date

20240430

Claims (4)

1. A combination upper nozzle and upper plate used for a slide gate, the combination upper nozzle and upper plate comprising gas blowing portions in two places, wherein one gas blowing portion is capable of blowing a gas to at least an upper portion of an upper nozzle, and the other gas blowing portion is capable of blowing the gas simultaneously to a lower portion of the upper nozzle and a sliding surface of an upper plate.
2. The combination upper nozzle and upper plate according to claim 1, wherein the other gas blowing portion includes a branch portion inside the upper nozzle.
3. The combination upper nozzle and upper plate according to claim 1 or 2, wherein the upper nozzle includes an upper porous refractory, a middle refractory, and a lower porous refractory, the one gas blowing portion is capable of blowing the gas to the upper porous refractory, and the other gas blowing portion is capable of blowing the gas to the lower porous refractory.
4. The combination upper nozzle and upper plate according to claim 3, wherein the other gas blowing portion is connected to a ring-shaped slit formed in the lower porous refractory.

Description

Technical Field The present invention relates to a combination upper nozzle and upper plate used for a slide gate. Background Art A slide gate (also referred to as a slide nozzle) is placed in the bottom of a tundish to regulate the flow of molten steel. The slide gate includes an upper nozzle, an upper plate, a lower plate, and a submerged entry nozzle. In a case of continuous casting for a long time, the submerged entry nozzle needs to be frequently replaced during continuous casting. In this case, the upper nozzle and the upper plate are integrated into a combination upper nozzle and upper plate, the lower plate and the submerged entry nozzle are integrated into a combination lower plate and submerged entry nozzle, and it is configured in such a manner that the combination lower plate and submerged entry nozzle is slid relative to the combination upper nozzle and upper plate to control the outflow of molten steel and the submerged entry nozzle can be replaced quickly. Even if continuous casting is not performed for a long time, the upper nozzle and the upper plate are still integrated into the combination upper nozzle and upper plate. In the known combination upper nozzle and upper plate, a gas such as an inert gas is blown to the upper nozzle to prevent alumina from adhering to an inner surface of a hole of the upper nozzle. Moreover, the gas such as an inert gas is blown to a sliding surface of the upper plate to prevent entraining air into the molten steel (refer to Patent Literature 1). In order to blow the gas to the upper nozzle and blow the gas to the sliding surface of the upper plate, gas blowing portions are provided in two places to the combination upper nozzle and upper plate. One gas blowing portion blows the gas to the upper nozzle, and the other gas blowing portion blows the gas to the sliding surface of the upper plate. Citation List Patent Literature Patent Literature 1: Description of U.S. Patent No. 5431374 Summary of Invention Technical Problem However, the combination upper nozzle and upper plate has the gas blowing portion for blowing the gas to the upper nozzle in only one place, and therefore, has a problem that alumina in molten steel is likely to adhere particularly to a lower portion of the upper nozzle. If the lower portion of the upper nozzle is clogged with alumina, there arise problems that operation needs to be stopped, the tundish needs to be replaced due to the reduced casting cycle time, and the replacement frequency of a refractory such as the submerged entry nozzle increases further. The present invention has been made in view of the above problems, and an object thereof is to provide a combination upper nozzle and upper plate capable of preventing alumina in molten steel from adhering to a lower portion of an upper nozzle where the alumina adheres heavily. Solution to Problem In order to solve the above problems, one aspect of the present invention is a combination upper nozzle and upper plate used for a slide gate, the combination upper nozzle and upper plate including gas blowing portions in two places, in which one gas blowing portion is capable of blowing a gas to at least an upper portion of an upper nozzle, and the other gas blowing portion is capable of blowing the gas simultaneously to a lower portion of the upper nozzle and a sliding surface of an upper plate. Advantageous Effects of Invention According to the present invention, the other of the gas blowing portions in the two places is capable of blowing the gas simultaneously to the lower portion of the upper nozzle and the sliding surface of the upper plate. Therefore, when a groove in the sliding surface of the upper plate is filled with the gas, the gas is preferentially supplied to the lower portion of the upper nozzle. Since a gas film can be stably formed in the lower portion of the upper nozzle, it is possible to prevent alumina from adhering to the lower portion of the upper nozzle. As a result, the casting cycle time is increased, the replacement of a tundish becomes less frequent, the replacement of a refractory such as a submerged entry nozzle becomes less frequent, and the economic effect is increased. Brief Description of Drawings Fig. 1 is a vertical cross-sectional view of a slide gate using a combination upper nozzle and upper plate of one embodiment of the present invention.Fig. 2 is a vertical cross-sectional view of one gas blowing portion of the combination upper nozzle and upper plate of the embodiment.Fig. 3 is a vertical cross-sectional view of the other gas blowing portion of the combination upper nozzle and upper plate of the embodiment.Fig. 4 is a plan view of the combination upper nozzle and upper plate of the embodiment. Description of Embodiment A combination upper nozzle and upper plate of an embodiment of the present invention is described in detail hereinafter with reference to the accompanying drawings. However, the combination upper nozzle and upper plate of the present in