JP2571364Y2 - Gas injector for metal degassing equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas injector for a degassing apparatus for molten metal, and particularly to a gas injector for degassing apparatus for molten aluminum. This is a proposal for an apparatus that can reduce the resistance to the molten metal and increase the degassing efficiency at the same time by forming a ceramic pipe.

[0002]

2. Description of the Related Art In recent years, the use of aluminum and its alloy materials has been expanding to advanced technology fields such as electronic equipment and automobile parts, and by entering such fields, the quality required for these materials has been increasingly increased. The fact is that things are getting tougher.

[0003] In order to meet such demands, efforts have been made to improve the quality of aluminum plates, their shapes and cast products, but for this purpose, the quality of the aluminum melt used as the raw material must be improved. It is necessary to perform a typical molten metal treatment.

[0004] The purpose of treating molten aluminum is classified into two types: degassing (hydrogen) and removal of nonmetallic inclusions. First, as a first treatment method for degassing, there are a chlorine gas treatment method, a nitrogen / chlorine mixed gas treatment method, a flux treatment method, and a vacuum method using vacuum. On the other hand, as a processing method for removing the second nonmetallic inclusion, there are a method using a ceramic foam filter, the same tube filter, a glass cloth filter, a flux processing method, and the like.

[0005] Each of these treatment methods has advantages and disadvantages. The chlorine gas treatment method and the vacuum method have a problem that the initial cost is high. The method using a filter can remove inclusions well, but has no effect on degassing. There was a problem that the filter did not work and the filter had to be replaced frequently. Further, the flux treatment method has a problem in terms of working environment.

As a technique for overcoming the problems of the conventional techniques relating to the treatment of molten aluminum described above, deoxidation is achieved by uniformly dispersing an inert gas such as nitrogen or argon into small bubbles in the molten metal uniformly. New methods for simultaneously realizing the degassing effect have been developed as Foseco's GBF process, Union Carbide's SNIF process, or Benesse's ALPUR process.

[0007] In particular, the above GB developed by Foseco
In the F process, the apparatus shown in FIG. 4 is used to disperse and eject fine bubbles of argon gas by the action of a plurality of grooves 9 provided at the bottom of the rotor 8 rotating at high speed to stir the molten metal 10. This is a method in which hydrogen and nonmetallic inclusions are efficiently adsorbed by bubbles of argon gas and floated and removed as dross, and have an excellent degassing effect.

[0008]

However, in the case of the above-described GBF processing apparatus, for example, as shown in FIG. 4, a vortex is generated in the molten metal due to the rotation of the disk-shaped rotor 8, and the degassing efficiency is reduced. However, there is a disadvantage that the oxidation of the molten metal proceeds.

As a method for correcting this defect, as shown in FIG. 5, there is a method in which a baffle plate (baffle plate or the like) 11 is immersed in a molten metal to prevent eddy currents and increase degassing efficiency. However, in this method, the rotating shaft 1
When the members such as the rotor 8 and the rotor 8 are made of carbon, there is a problem that the members are greatly consumed due to oxidation and abrasion and the running cost is increased. On the other hand, when the above members are made of ceramics, the initial cost is high and the economy is high. There was a problem.

An object of the present invention is to provide a device capable of overcoming the problems of the above-mentioned prior art, and in particular, a device capable of preventing oxidative abrasion of the molten metal itself without generating a vortex in the molten metal and having excellent degassing efficiency. The idea is to propose a gas injector for a degassing device at a low price.

[0011]

In order to solve the above-mentioned problems that require the above-mentioned solution, in the present invention, the basic structure of the gas injector is changed to a simple ceramic pipe structure having low resistance to molten metal. did. With such a configuration, degassing can be performed efficiently without generating a vortex in the molten metal, and a device applicable to any ladle (handheld furnace) can be obtained. . Moreover, since the constituent members have a simple pipe structure made of ceramics, it is possible to prevent the members from being worn out due to oxidation and wear, and to reduce running costs.

That is, the present invention provides a rotating shaft made of a ceramic pipe whose upper end is detachably attached to a rotor portion of a driving device; and a gas which is attached to a lower end of the rotating shaft and is supplied through the shaft to a processing vessel. Finger the bottom in the molten metal
And a downwardly opening gasket at a position where the joint portion extends to discharge the gasket in a downward direction.
L-shaped, T-shaped, and radial pipe-shaped gas discharger composed of a ceramic pipe gas discharge section having a gas discharge port, and the inner diameter of the processing vessel and the swirl diameter of the gas discharger are large.
The ratio of the magnitude to 1: 0.2 to 1: 0.35, and
The size of the turning diameter of this gas discharge body and the pipe of the gas ejection part
The ratio with the thickness is in the range of 1: 0.02 to 1: 0.2.
An injector for a degassing apparatus for molten metal .

[0013]

The gas injector according to the present invention is characterized in that the rotary shaft and the gas discharger, both of which are composed of simple pipes, are configured as shown in FIG. .

In FIG. 1, reference numeral 1 denotes a rotating shaft made of a ceramic pipe for supplying an inert gas for degassing, and a connector connected to a driving device (not shown) is provided at an upper end of the rotating shaft 1. 2 is connected. Reference numeral 3 denotes a pipe-shaped gas discharger attached to the lower end of the rotary shaft 1 for discharging gas supplied through the shaft 1 downward into the molten metal in the processing vessel , and is made of a ceramic pipe. It comprises a joint portion 4 and a gas ejection portion 5 also made of a ceramic pipe.

Here, the connector-2 is disclosed in
A connector as disclosed in Japanese Patent No. 85522, comprising a female thread formed in a large diameter member, and a large diameter member comprising a male thread provided on an outer periphery of a small diameter member screwed to the female thread. It is a connector for connecting to a small diameter member.

As shown in FIG. 2, the gas discharge body 3 has any one of an L shape, a T shape, and a radial shape, and has a joint portion 4 attached to the rotary shaft 1 for use. A gas ejection portion 5 provided at an extending position of the joint portion 4
It consists of: This can be formed integrally or separately, but when it is formed separately, it is desirable that the gas jetting part 5 has a structure detachable from the joint part 4.

The gas jetting portion 5 has a gas jetting port 6 around a tip end thereof for discharging in one or a plurality of directions directed to a bottom portion. When it is attached detachably, it is desirable that the length can be adjusted.

When the gas injector of the present invention having such a configuration is used, as shown in FIG. 3, the inner diameter X of the processing container 7 and the rotation of the gas discharger 3 are adjusted according to the size of the processing container 7 as shown in FIG. The ratio of the diameter Y to the diameter Y is in the range of 1: 0.2 to 1: 0.35, and the ratio of the swirling diameter Y of the gas discharge body 3 to the pipe thickness Z of the gas ejection portion 5 is 1 : 0.02 to 1: 0.2
Is preferable.

The reason for setting such dimensions is that when X is 1 and Y is smaller than 0.2, or when Y is 1 and Z is smaller than 0.1, the dispersion of the injected inert gas bubbles is reduced. On the other hand, when X is 1 and Y is greater than 0.35, or when Y is 1 and Z is greater than 0.2, the resistance to the molten metal increases. This is because a vortex is generated in the molten metal during the treatment, and as a result, the degassing efficiency deteriorates.

The ceramics used in the gas injector of the present invention include Si ₃ N ₄ , Sialon, and Si ₃ N ₄ -based composite ceramics (for example, BN + Si ₃ N ₄ and SiC + Si ₃ N _4).
Etc.) are preferable.

As described above, according to the gas injector having the above-mentioned structure according to the present invention, since the resistance is small, the vortex shown in FIG. 4 is not generated, and the molten aluminum in the processing vessel is not generated. Can be uniformly and efficiently stirred, and as a result, a so-called clean aluminum melt can be produced by degassing and removing nonmetallic inclusions.

The degassing efficiency of the gas injector according to the present invention can be further improved by periodically changing the rotation direction of the gas injector by a driving device.

[0023]

[Embodiment] (Embodiment) A gas discharge body at the lower end is placed in a ladle (inner diameter 750 mmφ, depth 800 mm).
) Using a gas injector made of Si ₃ N _{4 according} to the present invention set at a position about 100 mm away from the bottom, 500 kg of aluminum melt contained in the ladle is rotated at 300 rpm for 5 minutes, 0.1 to 1 kg. / cm ² injection pressure, 5-20 l / min. (0
(℃ ° C, 1 atm conversion), hydrogen and nonmetallic inclusions can be removed effectively, especially H ₂
The gas could be reduced from 0.38cc / 100g-Al to 0.10cc / 100g-Al.

Comparative Example A degassing process was performed in the same manner as in the example except that the processing apparatus shown in FIG. 4 was used, and the H ₂ gas was 0.38 cc.
/ 100g-Al to only 0.25cc / 100g-Al can be removed.
Furthermore, it can be seen that by performing the treatment for 15 minutes, the pressure is reduced to 0.20 cc / 100 g-Al, and the degassing efficiency is poor.

[0025]

As described above, the present invention employs a simple apparatus configuration consisting only of ceramic pipes having low resistance to the molten metal, thereby achieving efficient degassing without generating vortices in the molten metal. Can be.

Further, the apparatus of the present invention does not require a dedicated processing vessel, and can be applied to any vessel (hand-held furnace). In addition, since the part immersed in the molten metal is only a ceramic pipe, the so-called service life is reduced. In this respect, it is far superior to the conventional device. This device is advantageous in terms of cost both for production and maintenance.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of a gas injector according to the present invention in a case where a gas ejection port is directed to a bottom.

FIG. 2 shows an example of a joint shape of the gas injector of the present invention, (a) L
FIG. 4 is a perspective view showing a shape, (b) T shape, and (c) radial shape.

FIG. 3 is a view illustrating a usage state of the gas injector according to the present invention;

FIG. 4 is a diagram showing one use state of a conventional device.

FIG. 5 is a diagram showing another usage state of the conventional device.

[Sign]

 DESCRIPTION OF SYMBOLS 1 Rotary shaft 2 Connector 3 Gas discharge body 4 Joint part 5 Gas ejection part 6 Gas ejection port 7 Processing vessel 8 Rotor 9 Groove 10 Melt 11 Baffle plate

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshisho Matsuda 1-4-63 Ohama, Sakata-shi, Yamagata Japan Ceramics Development Center (56) References JP-A-63-86825 (JP) , A) Jikgyo 2-7868 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B22D 1/00 C21C 7/072 C22B 9/05 C04B 35/58

Claims (1)

(57) [Scope of request for utility model registration] 1. A rotating shaft made of a ceramic pipe whose upper end is detachably attached to a rotor part of a driving device;
And the gas supplied through the shaft attached to the lower end of the rotating shaft is directed to the bottom of the molten metal in the processing vessel .
And a downwardly opening gasket at a position where the joint portion extends to discharge the gasket in a downward direction.
L-shaped, T-shaped, and radial pipe-shaped gas dischargers comprising a ceramic pipe gas discharge portion having a gas discharge port, and the ratio of the inner diameter of the processing vessel to the size of the swirl diameter of the gas discharger.
In the range of 1: 0.2 to 1: 0.35, and
Ratio between the diameter of the turning diameter of the projectile and the thickness of the pipe at the gas outlet
In the range of 1: 0.02 to 1: 0.2.
Gas injector molten metal degassing apparatus according to symptoms.