JPH0730672Y2 - Gas injector for molten metal degassing device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a gas injector for a molten metal degassing apparatus,
Particularly, it is used for a degassing apparatus for molten aluminum, and particularly in the case of a lower constriction type processing container, it is effective by providing a form convenient for dispersing and jetting a stirring gas near the bottom of the container. The present invention relates to a gas injector devised to allow degassing.

[Background technology]

In recent years, the use of aluminum and its alloy materials has spread to cutting-edge fields such as electronic devices, and with the entry into such fields, the quality required for these materials is becoming more and more stringent. .

In order to meet these demands, efforts are being made to improve the quality of aluminum plates, their mold materials, and cast products, but in order to do so, the quality of the aluminum melt used as the material must be improved, and effective melt treatment is required. Need to do.

The methods of treating the molten aluminum are roughly classified into an in-furnace treatment method (batch treatment method) and an in-line treatment method (continuous treatment method). Of these, if the in-furnace treatment methods are further classified, there are four methods: a chlorine gas treatment method performed in the atmosphere, a nitrogen / chlorine mixed gas treatment method, a flux treatment method, and a vacuum method using vacuum (typically the Horst method). There is a processing method. On the other hand, when the in-line processing method is classified, a method using a ceramic foam filter or the same tube filter, or a method using a glass cloth filter is known.

Each of these processing methods has advantages and disadvantages.
The chlorine gas treatment or flux treatment method for batch processing in the atmosphere, the effect may be greater degassing efficiency of removing H _2, but thin effective in removing non-metallic inclusions, yet in terms of processing environment There was a problem. Further, the vacuum method has a fatal drawback that the initial cost is high. In this respect, the same applies to the case of one of the inline processing methods. Further, the method using a filter has a drawback in that although the inclusions can be removed well, the filter must be replaced frequently.

[Conventional technology]

On the other hand, as a technique for overcoming the drawbacks of the above-mentioned conventional techniques relating to the molten aluminum treatment, the inert gas such as nitrogen or argon is made into small bubbles in the molten metal and uniformly dispersed to remove the degassing. A new method of simultaneously realizing oxide and degassing effect,
As Foseco's GBF process, as Union Carbide's SNIF process, or as Pennecy's ALPUR
Developed as a process.

Among them, the conventional GBF process developed by Foseco is
This is a method of using a device as shown in FIG. In this method, extremely fine bubbles of argon gas are dispersed and ejected from a plurality of injection ports 103 provided on the peripheral side of a rotating body 102 that rotates through a cylindrical rotating shaft 101 that rotates at high speed, and the molten metal is melted. This is a method of homogenizing 104 by stirring and at the same time efficiently adsorbing hydrogen, oxides and non-metallic inclusions into the bubbles of argon gas to float and remove them as dross, and is excellent in degassing effect.

[Problems to be solved by the device]

However, in the case of the GBF processing apparatus as shown in FIG. 3 described above, the apparatus has to be equipped with a driving machine (externally mounted, not shown) for rotating the shaft supporting the rotating shaft 101, so that the apparatus is large. However, there is a drawback that it becomes expensive.

Furthermore, in this GBF processing method, the H ₂ gas is increased by about 0.05cc / 100g · Al each time because it is transferred to the ladle and the holding furnace (hand-held furnace) via the GBF processing furnace. ~ 0.2c
c / 100g · Al H ₂ gas remained. Of course, this H ₂ gas did not hinder the casting of a sound casting with a good level, but it could be said that there was still room for improvement.

The main object of the invention is to propose a gas injector for a degassing device, which can overcome the drawback of being expensive due to the large-scale device construction.

Another object of the present invention is to provide a gas that works particularly effectively when the processing container for storing the molten metal is a crucible-shaped container having a lower conical shape, when the gas injection direction is directed so as to make a centripetal flow. I am proposing an injector.

[Means for Solving the Problems]

In order to overcome the above-mentioned problems that need to be solved, the present invention has a simple structure with less movement of the entire apparatus, and is capable of degassing to the same extent as the GBF processing apparatus described above. It was developed as a convenient gas injector that can also be applied to a ladle), and the main point is to provide an inwardly bent portion facing the lower part of the inner wall of the processing container and providing its tip. A plurality of ceramic gas inlet pipes with porous plugs attached to them, a distributor connected to the upper ends of these gas inlet pipes via a plurality of branch pipes, and a distributor connected to this distributor A gas distribution / injection mechanism (A) composed of a gas introduction pipe, and a support frame (B) composed of a vertical shaft and a horizontal shaft for holding the gas distribution / injection mechanism on the processing container, A gas injector for a molten metal degassing device, comprising:

[Action]

In the present invention, the gas injection pipe for feeding gas into the molten metal to be processed has its tip bent inwardly so as to face it, and the tip of the bent portion; A plug is attached. The upper end of the gas inlet pipe is connected to a distributor via branch pipes that are radially provided. That is, the gas distributed from this distributor into each gas inlet pipe through a plurality of branch pipes passes through the gas inlet pipe and is injected into the molten metal from the porous plug attached to the tip of the gas inlet pipe. Of.

At this time, the gas is injected into the central part of the container, rises in the central part of the container as it is, turns to the vessel wall side, and continues to be a downward flow. Through such circulation flow, degassing and deinclusion effects occur.

As described above, the circulating flow that emerges from the center of the inner side to the outer side is advantageous because the trapped inclusions are not rewound in the molten metal.

Further, in the present invention, the support frame can be moved up and down through an elevator such as a screw or a cylinder, as will be described later, and the position of the porous plug can be adjusted to the bottom or the wall by fine adjustment. On the other hand, it can be kept constant at all times, and is therefore effective in further assuring the above-mentioned actions and effects. The support frame is installed on the processing container by suspending and holding it with a crane or the like.

〔Example〕

In the present invention, the degassing device shown in FIG. 1 is composed of a gas distribution / injection mechanism part and a support mechanism part.

In FIG. 1, reference numeral A in the drawing denotes a gas distribution / injection mechanism portion, and B denotes a support mechanism portion thereof.

First, the gas distribution / injection mechanism is mainly composed of a distributor 1, a branch pipe 3, ... And a gas inlet pipe 5.

The distributor 1 is a box-shaped stainless steel container typified by a circle or a quadrangle to an octagon (any one of the quadrangle to the octagon is determined by the number of branch pipes), and a gas is provided on the upper surface of the container. A gas introduction pipe 2 connected to a generator (not shown) is connected, while a proper number of branch pipes 3 ... Radially project horizontally from the side of the distributor 1 via an adapter. I am doing it. .. are connected downward to the free ends of the branch pipes 3 through tubular connecting fittings 4. The so-called bubbling gas distributed through the distributor 1 is
It is injected into the molten metal 8 in the processing container 7 from the porous plug 6 attached to the tip of the gas feed pipe 5 through the branch pipe 3, the coupling fitting 4, and the gas feed pipe 5.

The gas inlet pipe 5 is made of a ceramic such as a silicon nitride sintered body, and its lower end portion is bent so that the plurality of pipes are inwardly facing each other. This is an important point of the construction of the present invention, and it is possible to obtain a degassing device that forms an upward flow at the center part and a downward flow at the vessel wall side. Therefore, the tip of the pipe is bent so that the injected gas is discharged slightly above the center of the container.
The porous plug 6 is detachably fixed to the end of the bent portion 5a by a method of fitting or fitting. Further, the bending angle of the bent portion 5a and the shape / fixing method of the porous plug 6 are not limited to the illustrated example and the above-described method.

Next, the support mechanism; that is, the support frame B that supports the gas distribution / injection mechanism A supports the horizontal joint 9a that connects the gas introduction pipe 2 and suspends and holds the mechanism A, and the horizontal joint 9a. The vertical shaft 9b includes an elevator 10 that uses hydraulic pressure or a screw. Therefore, the support frame B can be moved in the vertical direction as a whole, and the level of the gas distribution / injection mechanism A can be finely adjusted in the vertical direction. This is the mechanism A
It leads to variably adjusting the level of the porous plug 6 located at the lower end of the, and always works effectively to compensate for the desired gas injection.

Next, the embodiment shown in FIG. 2 shows an example in which the gas injector of the present invention is applied to a rectangular processing container 11, and in this case as well, the same injection as in the case of the lower constriction processing container 7 described above is performed. The gas flow circulates in such a way that it becomes an upflow at the center and a downflow near the wall.

In each of the above-described embodiments, the number of gas inlet pipes 5 is arbitrary, and as shown in FIG. 1, the gas inlet pipes 5 do not protrude radially from the side portion of the distributor 1 but from the bottom surface of the distributor 1. An appropriate number of branch pipes 3 ′ ...
May be connected to the upper end of.

The gas inlet pipe 5 is composed of a silicon nitride atmospheric pressure sintered body or the like, and the porous plug attached to the lower end thereof is
Materials such as Si ₃ N ₄ , SiC, C, and Al ₂ O ₃ are used, but it is preferable to select and use materials having substantially the same thermal expansion coefficient as the gas inlet pipe 5.

[Effect of device]

As described above, according to this invention, instead of the rotary drive mechanism for bubbling as in the conventional device, the porous plug is arranged near the bottom wall of the processing container, and the gas is ejected toward the center. Is performed, the damage to the vessel wall due to the jetted gas flow is small, and a dedicated processing container and processing furnace are not required. For example, a crucible-shaped processing container having a lower constriction may be used. Moreover, since the portion to be immersed in the molten metal consists only of the ceramic pipe and the porous plug, not only the size and weight can be reduced, but also the life is far superior to that of the conventional device. Therefore, this device is excellent in terms of price, production, and maintenance, and has not only the effect of degassing but also the effect of removing impurities such as non-metallic inclusions.

[Brief description of drawings]

1 and 2 are cross-sectional views showing the usage state of the gas injector according to the present invention, and FIGS. 3 (a) and 3 (b) are schematic diagrams of a conventional device. A: Gas distribution / injection mechanism B: Support frame 1 ... Distributor 2 ... Gas introduction pipe 3,3 '... Plunge pipe 4 ... Connection fitting 5 ... Gas inlet pipe 6 ... Porous plug 7 …… Processing container (bottom-bottom type) 8 …… Melted metal 9a …… Horizontal shaft, 9b …… Vertical shaft, 10 …… Elevator, 11 …… Processing container (square bottom type)

Claims (1)

[Scope of utility model registration request] 1. A plurality of ceramics gas inlet pipes each having an inwardly curved bent portion facing the lower part of the inner wall of a processing container and having a porous plug attached to the tip thereof, and the gases thereof. A distributor connected to the upper end of the inlet pipe via multiple branch pipes,
A gas distribution / injection mechanism (A) consisting of a gas introduction pipe connected to this distributor, and for holding this gas distribution / injection mechanism on the processing container,
A gas injector for a molten metal degassing device, comprising a supporting frame (B) composed of a vertical shaft and a horizontal shaft.