JPS6174766A - Packing material for nozzle hole - Google Patents

Abstract

PURPOSE:To obtain the rate of perforation of a nozzle hole higher than with the conventional packing material, to eliminate substantially the need for using dangerous oxygen and to improve the quality of a metallic product by using spherical particles in the stage of packing the output flow port of the nozzle provided to a vessel for a molten metal. CONSTITUTION:The spherical particles of alumina, magnesia, zirconia and carbon, etc. are clasified and adjusted and are then packed into the outflow port A. The molten metal of a high temp. is poured through such port into the vessel 5. The spherical particles have excellent fluidity and prevent the tendency to difficulty in outflow and clogging of the outflow port owing to the bringing which arises with the conventional packing material.

Description

[Detailed description of the invention] Industrial field of application: The invention relates to a filling material for a nozzle hole for controlling the flow rate of molten metal attached to a container for molten metal such as a ladle or a tundish (hereinafter referred to as a container). It is something.

Prior Art: Control of the flow rate of molten metal drawn from a vessel includes
Usually a sliding nozzle is used. An example of this sliding nozzle is shown in the figure 1, in which two sliding nozzle plates are usually installed under the upper nozzle (2) attached to the container (5), and the upper part is fixed. Opening/closing or flow rate control is performed by positioning the sliding plate (4) on the lower side with respect to the plate (3).When receiving steel using this D sliding nozzle, after receiving the steel, the molten metal flows into the container. Since the molten metal is injected into the outlet (5), the temperature of the molten metal in this part decreases, solidifies, flows, and hits the sliding plate (4) of the sliding nozzle. The problem was that the molten species did not flow out even if the holes were opened. Once the molten metal has solidified, the molten metal is often flushed out by the chlorine gas. However, such means are extremely difficult to work with, and furthermore, the molten metal is oxidized, resulting in poor quality.

It has also been proposed that the outlet (5) be filled with various filler materials (1) in advance and then filled with steel to prevent the molten metal from penetrating into the outlet (5) and solidifying at the tip. However, it is not possible to obtain a material that is sufficient as a filler material to achieve the purpose, and the current situation is that molten metal flows out by relying on the oxygen gas mentioned above.

Purpose of the invention: The present invention has been developed in view of the current situation, and is designed to prevent molten metal D from entering into the filling area when the nozzle hole, which is the outlet, is filled, and to prevent the molten metal from entering the nozzle hole of the present invention. The material and ゛ζ will be explained in detail.

Conventional filling materials use crushed products such as silica stone, waxite, and alumina, and these are so-called non-spherical particles with sharp corners and edges. When used as a material, the friction between the particles and the friction between the particles and the nozzle: between the refractory holes J and D becomes a dog, and the fluidity is extremely poor. The particles do not flow and discharge, and the entanglement effect between particles increases due to the load pressure caused by the molten metal, resulting in a bridging phenomenon? Induced filling made the outflow of the family even more difficult.

The filling material of the present invention has a particle shape that does not cause such outflow obstruction, and uses spherical and so-called spherical particles close to spherical.The material is mainly composed of alumina, magnesia, zircon, zirconia, etc. The oxides of (1) and (3) and (3) are preferred, and these can be obtained singly or in appropriate combinations.

Such spherical particles are suitable for the spherical particles of the present invention, as shown in the graph shown in FIG. 2 showing the relationship between the friction angle between the particles and the iron plate, and the graph shown in FIG. 3 showing the IA yarn between the particles and the angle of repose. Although it has excellent i-dynamics, it is difficult to flow out of the nozzle hole while it is filled, as seen in conventional examples. In reality, there is no tendency to become obstructed.

That is, by using spherical particles, the fluidity is improved and the effect as a filling material for the nozzle hole is improved, and the material R is preferably alumina, magnesia, zircon, zirconia, or carbon. Among them, carbonaceous spherical particles have a remarkable improvement in fluidity due to the lubricity of the carbon itself, and their poor wettability to molten metal makes it easier to prevent molten metal from penetrating into the filling material. Contribute to achievement.

In the present invention, it is possible to use spherical particles to which 20 g of alkalis such as Na2O, CaO, etc. and 20 g of Fe are added as sintering modifiers to each spherical particle other than carbonaceous particles. The effect of this sintering and conditioning agent on the nozzle hole filling material is that only the surface portion of the filling aggregate of filling material (1) is properly sintered by the molten metal, which contributes to preventing the intrusion of molten metal. That's true. If the additive of this sintering modifier is less than 1wt, sintering assistance and young fruits cannot be obtained, and if it exceeds IQwt, a large amount of low melting point substances will be produced, and the packed aggregate itself will become thick and long. This will make it difficult to leak, so the above range should be set.

The present invention achieves the requirements for ensuring the fluidity of the filling material and preventing the intrusion of molten metal by using essentially carbonaceous spherical particles as a filling material, or by using spherical oxide particles and adjusting the particle size. is fully achievable. In addition, by using carbon-contributing spherical particles and oxidizing substance spherical particles together, and furthermore, by intensively coordinating and filling the carbonaceous spherical particles in the contact area with the molten metal, the effect of maintaining all the above requirements becomes even more difficult. .

Example 1: Alumina, magnesia, having the composition shown in Table 1
Zirconia-based carbonaceous spherical particles with a particle size of 3 to 0.2
300 tons of molten metal at 1660°C was injected into the outlet shown in Fig. 1, and the molten metal was allowed to stay there for about 457 days. 4) After seven cycles of excitation, the effective diameter t of the nozzle hole was evaluated as the ratio of the diameter before the start and the total shoulder porosity, and the results are also shown in Table 1. :4.

In addition, conventionally used silica sand filler (particle size 2 to 0.5
H) The same procedure was carried out for K, and it was shown as Comparative Example Chu9.

Example 2: Table 2 shows the fruit set using alumina spherical particles prepared in the same manner as in Example 1, in which feldspar was mixed with the alumina raw material and the amount of alkali was adjusted to various levels. Regarding Inventive Seed 13, the total residence time of the molten n metal was lengthened, but tt! ! The results were spectacular.

Effects of the invention: As is clear from the results of the examples shown in Tables 1 and 2, by using spherical particles, a higher opening ratio of the nozzle hole can be obtained than with conventional fillers, and at the same time, extremely dangerous work can be avoided. There are 11
? The filling material of the present invention has great utility in the production of beams, since there is almost no need for operations using diatomic gas, and the quality of the steel has been further improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram when the filling material of the present invention is applied to the nozzle hole of a molten metal container, Fig. 2 is a graph showing the ratio of the friction angle between the i particle and the wall surface, and Fig. 3 is the particle This is a graph of diameter and angle of repose shown by a person concerned. (1)...Filling material for the nozzle hole (2)...Upper nozzle (3)--Fixed plate (4)...Sliding plate (5)...Container (G)...Flow Exit Jinini''

Claims (1)

[Scope of Claims] 1. Refractory powder that is filled in advance into the outlet of a nozzle attached to a molten metal container in order to prevent blockage due to solidification of molten metal at the outlet of the nozzle, which contains alumina, magnesia, zircon, zirconia, etc. A filling material for a nozzle hole characterized by using spherical particles and/or carbonaceous spherical particles containing an oxide as a main component. 2. In the spherical particles mainly composed of an oxide according to claim 1, the alkali and iron oxide are contained in an amount of 1 to 10 w.
A filling material for a nozzle hole, characterized by comprising spherical particles containing t%.