JP2000094122A - Device for discharging molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharging device for molten metal, which prevents air from being dragged in from the joint part of a refractory caused by the negative pressure in a molten metal passing-through hole developed with the stream of molten metal and does not develop the lowering of the quality of molten metal and reduces the consumption of inert gas. SOLUTION: This discharging device for molten metal is provided with the refractory forming a slide gate 2 for controlling the stream of molten metal and nozzles 4, 6, 7 fitted to this slide gate 2, and an annular inert gas blowing pipe 14 disposed by concentrically surrounding so as to be faced to the joint part 13 of the refractory. In this inert gas blowing pipe 14, inert gas blowing holes 15 are arranged and positioned in the range so that the angle of elevation from an arbitrary point assumed on the outer periphery of the above joint part becomes 20-70 deg., and so as to be faced to the arbitrary point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal discharging device, and more particularly to a molten metal discharging device in which air is prevented from being entrained from a refractory joint.

[0002]

2. Description of the Related Art Generally, in a continuous casting facility, a molten metal discharging device for adjusting the flow rate of molten metal is provided at the bottom of a container for storing molten metal.

As shown in FIG. 5, a molten metal discharging device 21 generally used in the prior art includes a slide gate 22 for controlling the flow of molten metal, an upper nozzle 24 for attaching the slide gate 22 to a container 23, and a molten metal. Nozzle 26 for discharging the liquid into the mold 25, and the immersion nozzle 26
Are attached to the slide gate 22 and an intermediate nozzle 27 is separately formed. The slide gate 22 has a fixed plate 29 provided with a molten metal passage hole 28 and a slide plate 3 provided with a communication hole 30.
1.

[0004] In such a molten metal discharge device 21, the molten metal passage hole 28 is opened and the molten metal is passed through the upper nozzle 24, the molten metal passage hole 28, the communication hole 30, and the intermediate nozzle 2.
7 and the immersion nozzle 26 and discharge to the mold 25, the molten metal flow causes the molten metal discharge device 21 to have the upper nozzle 28, the molten metal passage hole 22, the communication hole 24, the intermediate nozzle The inside of the flow passage 32 formed by the immersion nozzle 30 and the immersion nozzle 29 becomes negative pressure, and air is drawn in from the joint of each refractory, oxidizing the molten metal and deteriorating the quality in some cases.

Conventionally, as shown in FIG. 6, a ring-shaped inert gas injection pipe 34 concentrically faces a refractory joint such as a joint 33 between the intermediate nozzle 30 and the immersion nozzle 29. From the inert gas blow-in port 35 provided in the inert gas blow-in pipe 34.
To prevent air from being drawn into the flow passage 32 from the joint 33.

[0006]

However, the inert gas inlet 35 of the conventional inert gas inlet pipe 34 has a joint 3
3 is disposed on the outer peripheral side perpendicular to the outer peripheral portion 36 (point P33), so that it is not possible to sufficiently prevent air entrainment. Activated gas was required, which was uneconomical.

The present invention has been made in view of the above circumstances, and prevents air from being entrained from a joint of a refractory due to a negative pressure in a flow passage caused by a flow of a molten metal, thereby improving the quality of the molten metal. It is an object of the present invention to provide a molten metal discharge device that does not decrease and uses less inert gas.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the invention of claim 1 of the present application is directed to a slide gate attached to the bottom of a molten metal container and controlling the flow of molten metal, and attached to the slide gate. And a ring-shaped inert gas injection pipe arranged concentrically around and facing the joint of the refractory, and the inert gas injection pipe has An inert gas inlet is provided, and the inert gas inlet has an elevation angle of 20 to 7 from an assumed point on the outer periphery of the joint.
The gist of the present invention is a molten metal discharging device that is located in a range where the angle is 0 ° and is provided to face the arbitrary point.

According to a second aspect of the present invention, there is provided a molten metal discharging apparatus according to the first aspect, wherein the joint of the refractory is a joint of a slide gate and an upper nozzle. .

According to a third aspect of the present invention, there is provided a molten metal discharging apparatus according to the first aspect, wherein the junction of the refractory is a junction between a slide gate and an intermediate nozzle. .

According to a fourth aspect of the present invention, there is provided a molten metal discharging apparatus according to the first aspect, wherein the joint portion of the refractory is a joint portion of an intermediate nozzle and an immersion nozzle. .

According to a fifth aspect of the present invention, there is provided a molten metal discharging apparatus according to the first aspect, wherein the joint of the refractory is a joint of a slide gate and an immersion nozzle. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a molten metal discharging device according to the present invention will be described below with reference to the accompanying drawings.

A molten metal discharging apparatus 1 according to the present invention as shown in FIG. 1 includes a slide gate 2 for controlling the flow of molten metal, an upper nozzle 4 for attaching the slide gate 2 to a container 3, and a molding of molten metal. The immersion nozzle 6 for discharging the immersion nozzle 5 and the intermediate nozzle 7 for attaching the immersion nozzle 6 to the slide gate 2 are separately assembled by joining refractories. The slide gate 2 includes a fixed plate 9 provided with a molten metal passage hole 8 and a slide plate 11 provided with a communication hole 10.

Therefore, a flow passage 12 is formed in the molten metal discharge device 1 by the upper nozzle 4, the molten metal passage hole 8, the communication hole 10, the intermediate nozzle 7, and the immersion nozzle 6.

On the outer peripheral side of the joint portion of the refractory formed separately, for example, the joint portion 13 between the immersion nozzle 6 and the intermediate nozzle 7, a ring shape which concentrically surrounds the joint portion 13 facing the joint portion 13 is provided. The inert gas injection pipe 14 is disposed. The inert gas injection pipe 14 has a pipe thickness of, for example, 3.2 m in order to regulate the flow of the inert gas.
m or more, but if it is thinner than 3.2 mm, a guide piece may be attached to the inert gas inlet 15. The inert gas injection pipe 14 is attached and detached by detaching the immersion nozzle 6 and the intermediate nozzle 7.

As shown in FIG. 2, the inert gas blowing pipe 14 is provided with a plurality of inert gas blowing ports 15 at an equal interval of 45 °, for example. For example, the joint 13
The inert gas inlet 15a corresponding to an assumed point P1 on the outer peripheral portion 16 of the outer peripheral portion 16 has a range such that the elevation angle from the arbitrary point P1 indicated by the straight lines L1 and L2 is 20 to 70 degrees, for example, 22. It is provided at a position where the angle is 5 °, and an arbitrary point P1
Facing. The other inert gas inlets 15 are also located at points P2 to P which are assumed to be at equal intervals of 45 ° from an arbitrary point P1.
8 are provided with a similar elevation angle of 22.5 °.

If the elevation angle is smaller than 20 °, the swirling flow of the inert gas does not effectively occur near an arbitrary point P 1,
If the angle is larger than °, the inert gas collides with the outer peripheral portion 16 of the joining portion 13 to generate a turbulent flow of the inert gas, and the effect of preventing the entrainment of air is reduced.

The number of the inert gas inlets 15 is not limited to eight, but may be nine to eighteen at equal intervals. When the inert gas inlet 15 is formed in a slit shape extending in the inner circumferential direction of the inert gas inlet pipe 14, the number may be eight or less.

Since the molten metal discharging device according to the present invention has the above-described structure, the sliding plate 11 is slid in the state shown in FIG. And the molten metal passage hole 8 is opened, and the flow path 1
2. Flow molten metal through 2. In addition, the inert gas injection pipe 14
And an inert gas is blown from the inert gas inlet 15 to the joint 13. Due to the flow of the molten metal, the inside of the flow passage 12 has a negative pressure, and air is easily taken in from the outside via the joint 13, but since the inert gas is blown from the inert gas inlet 15 to the joint 13. ,
The entrainment of air into the flow passage 12 is reduced.

In particular, the inert gas inlet 15a is located at an arbitrary point P1 on the outer peripheral portion 16 of the joint 13 with respect to the assumed point P1.
Since the angle of elevation from 1 is set at a position of 20 to 70 °, for example, 22.5 °, a swirling flow having an excellent air shielding effect can be generated in the vicinity of an arbitrary point P1. The amount of the active gas can effectively prevent air from being trapped in the flow passage 12.

In the above-described embodiment, the inert gas injection pipe is provided so as to face the joint 13 between the immersion nozzle 6 and the intermediate nozzle 7. However, the joint between the slide gate 2 and the upper nozzle 7, and the slide gate 2 The joint may be provided at any joint of the refractory, such as the joint with the intermediate nozzle 7, and the effect of the present invention can be obtained even if the joint is provided at all joints.

[0023]

EXAMPLES [1] Entrained gas amount measurement test (1) Test purpose: The position of the inert gas inlet is changed and the entrained gas amount is measured.

(2) Test device: As shown in FIG. 3, two deep dish-shaped containers are joined via a ventilation sheet simulating a joint portion to form a cylindrical container simulating a molten metal discharging device. Inert gas simulating molten metal can be introduced into the cylindrical container. The cylindrical container is provided with an oxygen concentration measurement sensor.

(3) Preparation of samples: The samples have elevation values as shown in Table 1, and as shown in FIG. 4, O1 (Example 1), O2
(Example 2) Five kinds of gas blowing pipes having eight inert gas blowing ports at positions corresponding to O3 (Example 3), O4 (comparative example) and O5 (conventional example) are produced.

(4) Measuring method: The sample is attached to the device (2), oxygen gas blown from the inert gas inlet of the gas blowing pipe is applied to the vicinity of the ventilation sheet, and the oxygen concentration measuring sensor puts the sample in the cylindrical container. Measure the concentration of entrained oxygen.

(5) Measurement results: Table 1 shows the measurement results.

[0028]

[Table 1] In the first to third embodiments, when the oxygen concentration value is 4 to 8%,
This is lower than that of the comparative example of 〜9% and that of the conventional example of 9〜１０10%, and it is found that the amount of the oxygen gas that is caught from the outside into the cylindrical container is small.

Example 1 was found to be the smallest at 4 to 5%, which was 50% of the conventional example.

[0030]

The molten metal discharging apparatus according to the present invention is provided with an inert gas inlet at a predetermined position of an inert gas injection pipe surrounding the outer peripheral portion of the joint, so that the molten metal discharging device is provided near the outer peripheral portion of the joint. A swirling flow having an excellent air shielding effect can be generated, and it is possible to effectively prevent air from being trapped in the flow passage with the same amount of inert gas as in the related art.

In particular, the inert gas injection pipe surrounds the refractory joint such as the joint between the slide gate and the upper nozzle, the joint between the slide gate and the intermediate nozzle, and the joint between the intermediate nozzle and the immersion nozzle. When provided, a remarkable effect of preventing air from getting into the flow passage can be expected.

[Brief description of the drawings]

FIG. 1 is a sectional view of a molten metal discharging device according to the present invention.

FIG. 2 is a molten metal discharging device according to the present invention,
Sectional drawing which follows the A line.

FIG. 3 is an explanatory view of a test apparatus used for a measurement test of an entrained gas amount.

FIG. 4 is an explanatory view of a gas injection pipe used for a test for measuring the amount of entrained gas.

FIG. 5 is an explanatory view of a commonly used molten metal discharging device.

FIG. 6 is a sectional view of a conventional molten metal discharging device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 molten metal discharge device 2 slide gate 3 container 4 upper nozzle 5 mold molten metal 6 immersion nozzle 7 intermediate nozzle 8 molten metal passage hole 9 fixed plate 10 communication hole 11 slide plate 12 flow passage 13 joint 14 inert gas blowing Pipe 15 Inert gas inlet 16 Outer periphery

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomoyuki Sugiyama 1 Minami Fuji, Ogakie-cho, Kariya-shi, Aichi F-term (reference) in Toshiba Ceramics Co., Ltd. Kariya Works 4E004 FB10 HA10 4E014 DB03 LA03 LA18 MA01 MA08 MA20

Claims (5)

[Claims] 1. A refractory formed at a bottom of a molten metal container and configured to form a slide gate for controlling a flow of the molten metal and a nozzle attached to the slide gate.
A ring-shaped inert gas injection pipe arranged concentrically around and facing the joint of the refractory; the inert gas injection pipe is provided with an inert gas injection port; The active gas injection port is located in a range such that an elevation angle from an assumed arbitrary point on the outer periphery of the joint becomes 20 to 70 °, and is provided to face the arbitrary point. And molten metal discharger. 2. The molten metal discharging device according to claim 1, wherein the joint of the refractory is a joint of a slide gate and an upper nozzle. 3. The joint of the refractory is a joint of a slide gate and an intermediate nozzle.
2. The molten metal discharging device according to claim 1. 4. The molten metal discharging apparatus according to claim 1, wherein the joint of the refractory is a joint of an intermediate nozzle and an immersion nozzle. 5. The joint of the refractory is a joint of a slide gate and an immersion nozzle.
2. The molten metal discharging device according to claim 1.