JPH02138425A - Device for degassing molten aluminum - Google Patents

Abstract

PURPOSE:To easily and efficiently degas molten Al at a low cost by arranging the tip of a bubbling pipe close to the peripheral wall in a treating vessel through the plural branches provided to a distributor, and injecting a gas from the tip. CONSTITUTION:Plural branches 2 free to radially oscillate and to be connected to a circular or polygonal box-shaped distributor 1 with a gas inlet pipe 4 connected to the upper surface through a flexible pipe 3 are pivoted on the bottom of the distributor 1. Plural bubbling pipes 11 are respectively fixed to the branches 2 through a connector 8, and a porous plug 12 is attached to the bend 11a at the tip. The device for degassing molten Al consisting of the manifold M and the bubbling pipe P is arranged in the treating vessel contg. molten Al. In this case, the branch 2 is oscillated through the slider 9 and link 10 sliding along a guide shaft 6, and the porous plug 12 is arranged in opposition to and close to the peripheral wall of the vessel. An agitating gas is blown in under such conditions to degas the molten Al.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a degassing device for molten aluminum, and in particular, to an apparatus for effectively degassing by injecting stirring gas close to the vessel wall. This is a proposal for a device that can improve degassing efficiency by guiding a stirring flow.

〔Technology〕

In recent years, the use of aluminum and its alloy materials has expanded to advanced technology fields such as electronic equipment, and the reality is that the quality required of these materials has become increasingly strict as aluminum and its alloys have expanded into such fields. be.

In order to meet these demands, we developed aluminum plates.

Efforts are being made to improve the quality of the shapes and cast products, but in order to do so, it is necessary to improve the quality of the molten aluminum that is the raw material, and it is necessary to carry out effective molten metal processing.

Broadly speaking, processing methods for molten aluminum can be divided into two types: in-furnace processing method (batch processing method) and in-line processing method (continuous processing method).
There are three methods: chlorine gas treatment in the atmosphere, nitrogen/chlorine mixed gas treatment, and flux treatment, and a vacuum method using a vacuum (the Porst method is a typical example). On the other hand, as in-line processing methods, methods using ceramic foam filters, ceramic foam filters, and glass cloth filters are known.

Each of these processing methods has its advantages and disadvantages; for example,
Chlorine gas treatment and flux treatment, which are performed in batches in the atmosphere, are highly effective in removing Na and have good degassing efficiency, but are less effective in removing nonmetallic inclusions and have problems in terms of environmental friendliness. there were. The vacuum method has a fatal drawback of high initial cost. The same thing can be said about in-line processing; methods that use filters remove inclusions well, but are not effective at all in degassing, and require frequent filter replacement. It had the disadvantage of having to do it.

[Conventional technology]

On the other hand, as a technique to overcome the drawbacks of the conventional techniques related to molten aluminum treatment mentioned above,
Foseco's GBF process is a new method that simultaneously achieves deoxidation and degassing effects by creating small bubbles of inert gas such as nitrogen or argon in the molten metal and dispersing them evenly and uniformly. It has been developed as the 5NIF process by the company, or as the ALPUR process by Benesee.

In particular, the GBF process developed by Foseco uses a device as shown in Figure 4 to inject extremely fine argon gas from multiple nozzles 42 installed on the circumferential side of a rotor 41 rotating at high speed. The bubbles are dispersed and ejected to form the molten metal 4.
3 is homogenized by stirring, and at the same time, hydrogen, oxides, and non-metallic inclusions are efficiently adsorbed into argon gas bubbles and floated away as dross, which has an excellent degassing effect.

[Problem to be solved by the invention]

However, in the case of the GBF processing apparatus described above, for example, as shown in FIG. The disadvantage is that it becomes more expensive and more expensive. Furthermore, in this GBF method, 0.05cc/100g of Hz gas is transferred each time to the ladle and further to the holding furnace (hand furnace) via the GBF processing furnace. The level increases, eventually reaching 0.1-0.2 cc/100g.
The H2 gas of A&' was left behind.

Of course, this H2 gas level was not an obstacle to casting sound castings, but it could be said that there was still room for improvement.

SUMMARY OF THE INVENTION An object of the present invention is to propose a degassing device that can overcome the drawbacks of the prior art, that is, the GBF processing device, which is expensive due to its large-scale device configuration.

[Means to solve the problem]

In order to solve the above-mentioned problem, the overall structure of the device should be simple with less movement, while still being able to achieve at least the same level of degassing as the BGF treatment device mentioned above. ), the present invention provides a circular or polygonal box-shaped distributor having an inlet pipe connected to the upper surface and a guide shaft protruding from the lower surface, and a distributor having a circular or polygonal box shape at the bottom of the distributor. A manifold consisting of a plurality of branches that are pivotally controlled in a swingable manner, and a plurality of flexible tubes for communicating between the disk, tripulator, and each branch; A degassing device for molten aluminum is proposed, comprising: a plurality of bubbling pipes that can be attached to each other, and in which a porous plug attached to the lower end, particularly the tip thereof, is held facing near the peripheral wall in the processing vessel; .

That is, the present invention is mainly composed of a manifold and a bubbling pipe, and has a configuration as shown in FIG.

In FIG. 1, the illustrated symbol M is a manifold,
P refers to bubbling pipe.

First, the manifold M is composed of a distributor 1, branches 2..., and flexible tubes 3....

The distributor 1 is a box-shaped container that is typically circular, square, or hexagonal (the square or hexagonal shape is determined by the number of branches and pipes), and a gas generator (not shown) is mounted on the top of the container. An inlet pipe 4 is connected thereto, an appropriate number of adapters 5 are protruded from the sides thereof, and a guide shaft 6 is protruded from the center of the bottom surface. Further, lug plates 7 corresponding to the number of branches are protruded from one bottom of the distributor.

The branch 2 has a short tubular shape that connects the distributor 1 and the bubbling pipe P, and has an adapter 5 protruding from its side for connecting the flexible tube 3, Furthermore, a connector 8 for connecting a bubbling pipe is screw-fitted at the lower open end. The branch 2 is swingably supported in suspension by pivotally connecting the tongue piece 2a provided at the top thereof to the lug plate portion 7 of the distributor 1. That is, this branch 2 is pivotally connected to a slider 9 that is loosely fitted to the guide shaft 6 through links 10 provided on its inward side, and the slider 9 is connected to the guide shaft 6. As the branch 2 moves up and down along the guide shaft 6, the i-end of the branch 2 is brought closer to or moved away from the guide shaft 6, thereby swinging.

The flexible tube 3 is made of metal and has a shape of a herringbone that is flexible so that it can follow the movement of the movable branch 2, and connects the distributor 1 and the branch 2 via adapters 5, 5>. It is something to do.

Next, the bubbling pipe P includes a pipe main body 11 having a bent portion 11a at the distal end on the gas release side, and the bent portion 11a.
It consists of a porous plug 12 made of ceramics such as silicon nitride or alumina fitted into the bent part 1.
The ends opposite to 1a are removably attached to the open ends of the branches 2 through connectors 8, thereby connecting them to the manifold M.

[For production]

The above-described degassing device according to the present invention does not have a rotating nozzle like the GBF processing device shown in FIG. By stirring the molten aluminum evenly and efficiently, it is degassed and purified, producing what is called a clean molten aluminum.

For this purpose, in the apparatus of the present invention, the porous plug 12 attached to the tip of the bubbling pipe P is opened to face near the inner peripheral wall of the processing container 13, as shown in FIG. It was designed to quickly rise along the wall. That is, a plurality of bubbling pipes P... extending from the manifold M are supported so as to be spread downward in a downwardly extending manner, and the extent (angle) of the legs may be adjusted and swingable. By providing a bent portion 11a at the tip of the bubbling pipe P, the porous plug 12 is configured to correctly face the wall surface.

As a result, the molten aluminum 14 in the processing container 13 undergoes wall surface flow due to the action of the jet gas and is agitated. At that time, the blown gas entrains residual gas and nonmetallic inclusions such as 112 to promote degassing,
At the same time, it promotes cleanliness.

In addition, in the apparatus of the present invention, in order to effectively perform degassing as described above, the bubbling pipe P is
In addition to the porous plug 12 that injects gas that opens near the inner bottom of the processing container 13, there are also
As shown in bl, it is preferable to provide a short container 14 that opens at the middle of the processing container 13. Moreover,
This shortened pipe 14 does not need to be uniformly opened near the wall surface like the long pipe main body 11, but can be set at any angle suitable for changing the swinging angle and promoting bubbling. It is desirable to expand the effective bubbling area by fixing the bubbling surface to

Note that there is no limit to the number of these pipes 11 and 14,
The number can be any number of branches, but this number is the same as the branch 2...
The number corresponds to the number of adapters 5 protruding from the distributor 1.

As explained above, the device of the present invention has the inlet pipe 4
The gas introduced into the distributor 1 through the distributor 1 is distributed evenly in this distributor 1 section, and then passed through the flexible tubes 3... to each branch 2...
The molten metal is sent through the pipes 11 and 14, and is injected into the molten metal in the container through the porous plug 12 at the tip.

Of course, this device does not require a special container and uses a ladle called a hand furnace, so it is necessary to adjust the position of the porous plug 12 facing the wall depending on the size of the furnace. Therefore, by raising and lowering the slider 9 attached to the guide shaft 6, the opening angle of the pipe 11 is adjusted.

Also, if the size of the container (furnace or ladle to be treated) is determined, a pipe angle adjustment mechanism is not necessary.
The distributor may be directly connected to each pipe without using a flexible tube.

〔Example〕

The distributor, flexible tube and branch are all made of stainless steel, and four 5iJ
Using a degassing device equipped with a 4-made bubbling pipe (inner diameter 2 inches φ) and a porous plug attached to the tip, 5
00 kg of molten aluminum for 15 minutes, 3-4
kg/cm” injection pressure, 30~40J/min,
Bubbling at 0°C (1 atm) can effectively remove hydrogen and nonmetallic inclusions, especially H,
Gas is 0.2cc/100g-Aj! was able to reduce it to.

〔Effect of the invention〕

As explained above, the present invention has a simple device configuration consisting only of a manifold and pipes without including a drive mechanism for bubbling as in the past, and does not require a dedicated processing container. ), and because the only parts that are immersed in the molten metal are the ceramic pipe and plug, it far exceeds conventional equipment in terms of so-called service life. This device is advantageous in both production and maintenance in terms of cost, and is naturally excellent not only in degassing effects but also in removing impurities such as nonmetallic inclusions.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of the degassing device of the present invention, Fig. 2 is a cross-sectional view showing how the device of the present invention is used, and Fig. 3 is a diagram showing other uses of the degassing device of the present invention. Figure 4 (al is a route map from the top, route map from the side, FIG. 4 (al is a route map of the conventional device, and FIG. 4(b) is a plan view of the rotor. Yes. M...Manifold, P...Bubbling pipe, 1
...Distributor, 2...Branch, 3...
・Flexible tube, 4...In left pipe, 5...Adapter 6...
・Guide shaft, 7... Lug plate, 8... Connector, 9... Slider, 10... Link, 1
1...bubbling pipe body, lla...bending part,
12... Porous plug, 13... Processing container, 14
...shortened pipe. Patent applicant: Japan Heavy and Chemical Industry Co., Ltd. Agent Patent attorney: Jun Ogawa Patent attorney: Morio Nakamura No. 4 (Q) 7Aγ N (No. 2 No. 3 (G) (b)

Claims (1)

[Claims] 1. A circular or polygonal box-shaped distributor having an inlet pipe connected to the upper surface and a guide shaft protruding from the lower surface, and a rotatably supported and rotatably mounted distributor at the bottom of the distributor. a manifold consisting of a plurality of branches installed in the manifold, and a plurality of flexible tubes for communicating between the distributor and each branch; In particular, a degassing device for molten aluminum comprising: a plurality of bubbling pipes, each of which has a porous plug attached to its tip and is held facing near a peripheral wall in a processing container; 2. The apparatus according to claim 1, wherein the branches of the manifold and the bubbling pipe are mounted radially around the distributor. 3. The bubbling pipes have tip portions facing the inner wall of the processing container arranged in two stages, some of which are located at the bottom of the container and some of which are located in the middle of the container. 2. The device according to claim 1.