JPH0343227Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a light alloy melting furnace for melting light metals such as aluminum alloys and magnesium alloys. This invention relates to a light alloy melting furnace that is used to supply molten metal with a low hydrogen gas content in order to cast cast products.

[Prior art]

Conventionally, this type of light alloy melting furnace has mainly been a reverberatory furnace that melts light alloy materials using radiant heat from a heavy oil burner or a gas burner. In this reverberatory furnace, it is customary to perform no degassing and refining inside the melting furnace, but only a sludge removal process using flux. The degassing refining process, which is essential for obtaining high-quality molten metal with low hydrogen gas content and high purity, is configured to be carried out in a forehearth or holding furnace connected to a reverberatory furnace. The molten metal transferred from the reverberatory furnace was degassed and refined in a forehearth or holding furnace, and then fed to molds, casting machines, etc.

In addition, in recent years, as shown in FIG. 5, instead of using radiant heat to heat the material, the material A charged into the melting chamber 30 is heated with direct flame by the burner 31 to shorten the melting time. , an energy-saving melting furnace 32 in which the material charging part into the melting chamber 30 is also used as a flue, and material A is preheated by exhaust gas.
has come to be generally adopted. Even in this type of melting furnace 32, although the melting speed is fast, it is difficult to adjust the amount of hot metal and refine it, so the fact is that it is equipped with a forehearth 33 and a holding furnace (not shown) in addition to the melting furnace 32. It is.

When refining aluminum alloys, the following procedure is usually used.

(1) De-slag treatment This treatment is performed inside the holding chamber 34 of the melting furnace 32. After the material has melted down, basic fluxes such as Nac, Kc, NaF, etc. are added to the molten metal at a relatively low temperature of around 700°C, and about 1% of the molten metal is added, and the molten metal B is refined while stirring, and the floating slag is removed. It is done by folding.

(2) Degassing treatment This degassing treatment is usually carried out in the forehearth 33 or a holding furnace (not shown), and the treatment methods can be roughly divided into: treatment by adding a degassing flux containing hexachloroethane, treatment by adding a degassing flux containing hexachloroethane, chlorine gas Treatment by blowing in nitrogen gas. Treatment by blowing in nitrogen gas, etc. In large melting furnaces, lances are often used for processing using the above method or the method described above. Although the above treatment methods have a large degassing effect, they generate chlorine gas that is toxic to the human body, and are therefore undesirable from the viewpoint of pollution prevention, and are currently no longer being used. Furthermore, since the above treatment method is a method of mechanically degassing hydrogen gas in the molten metal by adsorbing it to nitrogen gas bubbles, it is important to disperse as many bubbles as possible into the molten metal in a finer manner. .

[Purpose of invention]

The present invention has been made in consideration of the above-mentioned conventional problems, and is configured so that after melting, not only the de-slag treatment but also the degassing treatment can be performed in the holding chamber of the melting furnace, unlike the conventional forefurnace. The object of the present invention is to provide a light alloy melting furnace which eliminates the need for a holding furnace and enables direct supply of hot water from the melting furnace to a mold or casting machine, and which also has a sufficient degassing effect.

[Structure of the idea]

In order to achieve the above object, the light alloy melting furnace of the present invention is a melting furnace in which a holding chamber is formed in communication with the melting chamber and has a sump at the bottom of the furnace. An inert gas supply device connected to an inert gas supply source is installed, and the inert gas supply section at the lower end of the inert gas supply device is provided so as to be movable up and down so that it can be immersed in the molten metal in the holding chamber. At the same time, a porous plug that can come into contact with the molten metal in the sump is provided at the sending end of the gas supply path in the inert gas supply section, so that descaling and degassing can be carried out in the holding chamber. It is characterized by being configured so that it can be refined.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

The melting furnace 1 includes a melting chamber 3 formed inside thereof on the side of the material charging port 2, and a melting chamber 3 communicating with the melting chamber 3,
A holding chamber 5 formed on the outlet 4 side is provided. A melting chamber burner 6 is provided in the melting chamber 3, a holding chamber burner 7 is provided in the holding chamber 5, and a sump 8 is formed at the bottom of the holding chamber 5.

The material charging port 2 formed in the melting chamber 3 is connected to a flue 9.
The exhaust heat generated from the holding chamber 5 etc. is guided to the flue 9 through the melting chamber 3,
This allows the material charged in the melting chamber 3 to be preheated.

On the other hand, an inert gas supply device 10 is mounted on the ceiling of the holding chamber 5. As shown in FIG. 4, this inert gas supply device 10 includes an inert gas introduction pipe 11 connected to an inert gas supply source such as nitrogen gas, and a heat-resistant and It is equipped with an inert gas supply section 12 that is immersable. The introduction pipe 11 and the supply part 12 are formed with a gas supply passage 13 communicating therein, and the gas supply passage 13 formed on the supply part 12 side has a gas supply passage 13 at the feeding end of the gas supply passage 13 in the tundish part 8. A porous plug 14 is buried so as to be in contact with the molten metal B. The inert gas supply device 10 described above is mounted on the ceiling of the holding chamber 5, and the inert gas supply section 12 is normally on standby above the holding chamber 5, and the inert gas supply section 12 is turned on during degassing processing. It is configured to be movable up and down so that it can be lowered and immersed in the molten metal B in the holding chamber 5.

Further, the melting furnace 1 described above is provided so as to be tiltable by the cylinder 15, while the melting furnace 1 has a tap opening 4.
A rotating waterway 16 equipped with a toy preheating burner 21 and a toy heat-insulating cover 22 is installed adjacent to the toy preheating burner 21 and a toy heat-insulating cover 22 .
Three receiving ports 18 of No. 7 are formed.

In the above configuration, the procedure for melting and casting using the light alloy melting furnace of the present invention is as follows.

First, ingots and return material made of light alloy materials such as aluminum alloy are placed in the top bucket 19, and the hoist 20 equipped with an electric traverse mechanism is driven to transport the materials from the material charging port 2 of the melting furnace 1 into the melting chamber 3. At this point in time when the holding chamber 5 is charged, the inert gas supply section 12 provided in the holding chamber 5 is on standby at the rising end near the ceiling side of the holding chamber 5.

Next, when the material in the melting chamber 3 is melted down and melted by heating by the melting chamber burner 6, all the melting chamber burners 6 and holding chamber burners 7 are stopped.
The slag removal process is performed by flux refining at a molten metal temperature of approximately 700°C, and is performed in the same manner as in the conventional example described above.

When the slag removal process is completed, the holding chamber burner 7 is ignited to raise the temperature of the molten metal B collected in the sump 8 of the holding chamber 5 to approximately 750 to 760°C. Thereafter, the holding chamber burner 7 is stopped, and the supply section 12 of the inert gas supply device 10 is lowered to the hearth of the holding chamber 5, and immersed in the molten metal B. Porous plug 14 at this time
The immersion depth from the top surface to the molten metal surface is h, 450mm.
It is desirable to set the value above. In addition, in this type of light alloy melting furnace, the depth of the molten metal is usually 400 mm.
However, in the present invention, considering the amount of immersion of the inert gas supply device 10, the depth H of the holding chamber 5 is adjusted so that the depth H of the molten metal is 550 to 600 mm or more. It is preferable to set the depth to 8. As the depth H of the molten metal increases, for example, 600
mm depth, the upper part of the molten metal becomes about 20 to 30°C hotter than the lower part, causing an imbalance in the temperature distribution.This is because the molten metal is stirred by nitrogen gas bubbling, which will be described later. is equalized.

The supply section 12 of the inert gas supply device 10 is connected to the molten metal B.
After being immersed in the liquid and set at a predetermined position on the hearth, nitrogen gas is blown through the inert gas introduction pipe 11. This nitrogen gas is guided to the porous plug 14 by the gas supply path 13, and countless fine bubbles of nitrogen gas are generated from the porous plug 14. Since the bubbles stir the molten metal B, the temperature distribution of the molten metal B becomes uniform. In addition, the porous plug 14
The bubbles generated from the molten metal B adsorb hydrogen gas in the molten metal B before reaching the surface of the molten metal B, thereby performing a degassing process. By performing this degassing treatment for about 20 minutes, the hydrogen gas content in the molten metal B is reduced to about 0.12 cc/100g, and a clean molten metal with a low hydrogen gas content is obtained.

After the degassing process is completed, the residue floating on the surface of the molten metal B is removed, while the inert gas supply section 12 is raised to its original standby position. This prevents the porous plug 14 from clogging and facilitates maintenance. After that, the cylinder 15 tilts the furnace body to a predetermined angle of inclination, and the outlet 4
From there, the hot water is discharged to the swirling hot water path 16. This molten metal flows from the upstream end to the downstream end of the swirling channel 16, and is supplied to each inlet 18 that is set at the top of the sand casting machine 17 and serves as a sump.By pulling out a stopper (not shown), the mold cavity is closed. Hot water is poured into the water.

[Effect of idea]

As described above, the light alloy melting furnace according to the present invention is a melting furnace in which a holding chamber is formed that communicates with the melting chamber and has a sump at the bottom of the furnace, and an inert gas is provided in the ceiling of the holding chamber. An inert gas supply device connected to a supply source is installed, and the inert gas supply section at the lower end of the inert gas supply device is provided to be movable up and down so that it can be immersed in the molten metal in the holding chamber, Since the inert gas supply section has a structure in which a porous plug that can come into contact with the molten metal in the sump section is provided at the sending end of the gas supply path, degassing refining within the melting furnace becomes possible. As a result, the forehearth and holding furnace that were previously required are no longer necessary.
This significantly reduces manufacturing costs, downsizes the
In addition to reducing the installation space, it also becomes possible to supply hot water directly from the melting furnace to the mold or casting machine. In addition, since the porous plug is deeply immersed in the molten metal and generates fine inert gas bubbles, hydrogen gas in the molten metal can be efficiently adsorbed and degassed. It produces various effects.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view of the main part showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional front view of the main part, Fig. 3 is a plan view of the same, and Fig. 4 is an inert material forming a component of the invention. FIG. 5 is a longitudinal cross-sectional view of a conventional example, which is an explanatory diagram of the usage state in which the main part of the gas supply device is longitudinally cut. 1 is a melting furnace, 2 is a material charging port, 3 is a melting chamber, 5
1 is a holding chamber, 6 is a melting chamber burner, 7 is a holding chamber burner, 8 is a water reservoir, 9 is a flue, 10 is an inert gas supply device, 11 is an inert gas introduction pipe, 12 is an inert gas supply section , 13 is a gas supply path, and 14 is a porous plug.

Claims (1)

[Scope of utility model registration request] In a melting furnace in which a holding chamber is formed that communicates with the melting chamber and has a sump at the bottom of the furnace, an inert gas supply device connected to an inert gas supply source is attached to the ceiling of the holding chamber. , the inert gas supply section at the lower end of the inert gas supply device is provided so as to be movable up and down so as to be immersed in the molten metal in the holding chamber, and the sending end of the gas supply path in the inert gas supply section A light alloy melting furnace characterized in that a porous plug is provided that can come into contact with the molten metal in the sump.