JPH0744363Y2 - Inner coating injection pipe for tundish - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tundish injection pipe, and more particularly to a tundish inner surface coating injection pipe having a refractory coating as an inner surface release agent applied to the inner peripheral surface of the injection pipe.

[0002]

2. Description of the Related Art As a tundish injection pipe, a large-diameter straight pipe made of graphite-alumina, fused silica, or alumina castable refractory has been used.

Further, as disclosed in Japanese Utility Model Publication No. 2-17734, there is proposed a tundish pot having a tapered lower wide shape (Fig. 4 of the publication).

[0004]

In the conventional straight tube type injection pipe, for example, as shown in FIG. 2, metal adhesion occurs on the inner peripheral surface of the injection pipe, and finally the injection pipe is closed and the injection pipe is closed. It has been scrapped due to use, and as a result, the basic unit has been increased. Although such metal adhesion can be removed by an oxygen cleaning agent, this type of removal operation is complicated and dangerous and is not generally adopted.

Further, in the example described in the above publication, the metal adhesion is slightly reduced, but there is a defect such as melting loss in the molten metal immersion portion of the injection pipe.

[0006]

The inventors of the present invention succeeded in developing the injection tube of the present invention as a result of various examinations and experiments in order to solve the above-mentioned defects of the prior art. Technically, the injection pipe used for non-oxidizing injection of molten metal into a tundish has an inner surface whose inner surface taper angle (α) is 0.5 ° with respect to the axis of the injection pipe.
In an inner surface coated injection pipe for a tundish, which is inclined outwardly by 3.0 ° and has a refractory coating as an inner surface release agent having a thickness of 2 to 15 mm applied to the inner peripheral surface of the injection pipe. A detailed description will be given with reference to the accompanying drawings showing a specific example of the present invention.

FIG. 1 is a vertical cross-sectional view of the injection pipe of the present invention, and FIGS. 2 and 3 are schematic vertical cross-sectional views showing a state where the metal is attached and a state where the metal is peeled off.

As shown in the figure, the injection pipe (1) of the present invention has an inner surface inclined outward with an inner taper angle (α) of 0.5 ° to 3.0 ° with respect to the axis of the injection pipe. In addition, the inner surface of the injection pipe (1) is coated with an inner surface release agent.
The refractory coating (2) is applied, and the thickness of this coating layer is 2 to 15 mm.

In relation to the refractory coating, the inner taper angle is 0.5 ° to 3.0 ° in view of the peeling condition of the adhered metal and the thickness of the injection pipe wall.
If the angle is less than 0.5 °, the metal will not naturally fall due to cooling, and 3.
When the angle exceeds 0 °, peeling of the metal is good, but the thickness of the wall of the injection pipe becomes thin at the lower portion, the strength of the injection pipe itself becomes weak, and recoating-reuse becomes impossible.

The material of the injection pipe is mainly graphite-alumina refractory as in the conventional products, but fused silica refractory, alumina castable refractory, etc. can be used.

By using a refractory coating as an inner surface peeling agent applied to the inner peripheral surface of the injection pipe , which has a large linear thermal expansion change rate, the metal adhered to the inner surface falls during use and the amount of adhered metal is suppressed. The refractory coating shrinks and cracks by cooling the injection pipe after use, and the adherent metal peels off from the inner peripheral surface of the injection pipe together with the coating and spontaneously falls. Is illustrated in Table 1.

[0012]

The thickness of the refractory coating, which is the inner surface release agent, is 2 to 15 m in consideration of construction and adhesive strength to the inner surface of the injection pipe.
m is sufficient, and if it is less than 2 mm, uniform construction is difficult, and a thickness exceeding 15 mm is not necessary.

Iron coating and spraying are suitable for the coating of the refractory material, but other construction means can be used as long as they satisfy the above conditions.

When pouring a ladle into a tundish using the injection pipe of the present invention, the metal (3) adheres to the inner peripheral surface of the injection pipe through the coating layer (2) as shown in FIG. When the molten metal is completed and the injection pipe is removed and cooled, cracks are generated due to shrinkage of the coating as shown in FIG. Then, it was dropped naturally and the injection tube itself was in a state where it could be reused.

Therefore, such an injection pipe can be used repeatedly by re-applying the refractory coating.

[0017]

EFFECTS OF THE INVENTION (1) Since the injection pipe of the present invention is coated with a refractory material which is an inner surface release agent, the metal can be easily dropped and the injection pipe can be repeatedly used.

(2) By applying the refractory material coating as the inner surface release agent, the adhesion of the metal to the inner surface of the injection pipe is reduced, and the number of times the injection pipe is used is greatly extended.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of the injection pipe of the present invention.

FIG. 2 is a schematic vertical cross-sectional view showing the adhered state and the peeled state of the metal.

FIG. 3 is a schematic vertical cross-sectional view showing the adhered state and the peeled state of the metal.

[Explanation of symbols]

 1 Injection pipe 2 Refractory coating 3 Bare metal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Ote 7-1, 1-1 Aoyamadai, Tarumi-ku, Kobe-shi, Hyogo Prefecture (72) Inventor Katsumi Iwanaga 591-9, Fukudome, Kamino-cho, Kakogawa, Hyogo Prefecture (72) Inventor Kenichi Okuma 1426-6 Yoda, Onoue-cho, Kakogawa-shi, Hyogo (56) Reference JP-A-61-235049 (JP, A) Jikkouhei 2-17734 (JP, Y2)

Claims (1)

[Scope of utility model registration request] 1. An injection pipe used for non-oxidizing injection of a molten metal into a tundish, wherein the inner surface has an inner surface taper angle (α) of 0. 1 with respect to the axis of the injection pipe (1).
An inner surface for a tundish, which is inclined at 5 ° to 3.0 ° to the outside and has a refractory coating (2) as an inner surface peeling agent having a thickness of 2 to 15 mm applied to the inner peripheral surface of the injection pipe. Coated injection tube.