JPH0549148U - Gas injector for molten metal degassing equipment - Google Patents

Abstract

(57) [Summary] [Objective] To propose a gas injector for a low-cost degassing device that has excellent degassing efficiency without generating vortices in the molten metal. [Structure] A rotating shaft 1 made of a ceramic pipe having an upper end detachably attached to a rotor portion of a drive unit; and a gas attached through a lower end of the rotating shaft 1 and supplied through the shaft to a molten metal 10 of a processing container 7. An L-shaped, T-shaped, radial-shaped pipe-shaped gas discharger 3 consisting of a ceramic pipe-made joint part 4 and a ceramic pipe-made gas spouting part 5 in an extended position of the joint part 4 for discharging into the inside. Of the metal melt degassing apparatus, and a more preferable embodiment is such that the inner diameter X of the processing container 7 and the swirling diameter of the gas discharger 3 are adjusted according to the size of the gas injector. The ratio with Y is 1: 0.2 to 1: 0.
The ratio of the swirling diameter Y of the gas discharger 3 to the pipe thickness Z of the gas ejection portion 5 is 1: 0.02.
The size is in the range of to 1: 0.2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a gas injector for a molten metal degassing device, and is particularly suitable for being applied to a degassing device for molten aluminum, in which the constituent member of the injector is a ceramic pipe. This is a proposal for an apparatus that can reduce the resistance to molten metal and at the same time increase degassing efficiency.

[0002]

[Prior Art]

 In recent years, the use of aluminum and its alloy materials has spread to advanced technology fields such as electronic devices and automobile parts, and with the entry into such fields, the quality required for these materials is becoming increasingly severe. Is the reality.

In order to meet these demands, efforts are being made to improve the quality of aluminum plates, their shapes, and cast products, but for that purpose, the quality of the aluminum melt used as the raw material must be improved, which is an effect. It is necessary to perform a typical molten metal treatment.

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

Each of these treatment methods has merits and demerits, and the chlorine gas treatment method and the vacuum method have a problem that the initial cost is high. Although the method using a filter removes inclusions well, it is completely effective in degassing. However, there was a problem that the filter replacement was not performed frequently and the filter had to be changed frequently. In addition, the flux processing method had a problem in terms of working environment.

As a technique for overcoming the problems of the above-mentioned conventional techniques related to the treatment of molten aluminum, it is possible to form an inert gas such as nitrogen or argon into small bubbles in the molten metal and evenly disperse the same, thereby deoxidizing A new method of simultaneously achieving the degassing effect has been developed as the GBSE process of Foseco, the SNIF process of Union Carbite or the ALPUR process of Venecy.

Among them, the GBF process developed by Foseco Co., Ltd. uses a device as shown in FIG. 4, and a plurality of grooves 9 provided at the bottom of the rotor 8 rotating at high speed work to make fine argon gas. The bubbles are dispersed and jetted, and the molten metal 10 is stirred, so that hydrogen and non-metallic inclusions are efficiently adsorbed by the bubbles of argon gas and floated off as dross, which is excellent in degassing effect. ..

[0008]

[Problems to be solved by the device]

 However, in the case of the GBF processing apparatus as shown in FIG. 4, for example, the rotation of the disk-shaped rotor 8 causes vortices in the molten metal, which reduces degassing efficiency and promotes oxidation of the molten metal. there were.

As a method of correcting this drawback, as shown in FIG. 5, there is a method of dipping a baffle plate (baffle plate etc.) 11 in a molten metal to prevent swirling and improve degassing efficiency. However, in this method, when the members such as the rotary shaft 1 and the rotor 8 are made of carbon, there is a problem that the members are heavily consumed due to oxidation and abrasion, resulting in a high running cost. However, there is an economic problem that the initial cost is high.

An object of the present invention is an apparatus capable of overcoming the problems of the above-mentioned conventional techniques, and in particular, it is possible to prevent oxidative wear of the molten metal itself without generating vortices in the molten metal and to provide a low degassing efficiency. We are proposing a gas injector for a degassing device at a low price.

[0011]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems that need to be solved, in this invention, the basic structure of the gas injector is a simple ceramic pipe structure with low resistance to molten metal. With such a structure, it is possible to efficiently degas without generating vortices in the molten metal, and to obtain a device that can be applied to any ladle (hand-held furnace). .. Moreover, since the constituent members are made of a simple ceramic pipe structure, it is possible to prevent the members from being consumed due to oxidation and abrasion, and to reduce the running cost.

That is, according to the present invention, a rotary shaft made of a ceramic pipe having an upper end removably attached to a rotor portion of a drive unit; and a gas supplied through the rotary shaft attached to the lower end of the rotary shaft is disposed in a processing container. L-shaped, T-shaped, or radial pipe-shaped gas discharger consisting of a ceramic pipe joint for discharging into the molten metal and a ceramic pipe gas spout at the extended position of this joint, An injector for a molten metal degassing apparatus comprising a more preferable form, in which the ratio between the inner diameter of the processing container and the swirl diameter of the gas discharger is adjusted according to the size of the processing container. , 1: 0.2 to 1: 0.35, and the ratio of the swirl diameter of the gas discharger to the pipe thickness of the gas ejection part is in the range of 1: 0.02 to 1: 0.2. One in which the.

[0013]

[Action]

 A feature of the gas injector of the present invention is that both the rotary shaft and the gas discharge body, which are the constituents, are composed of a simple pipe material, and has a structure as shown in FIG.

In FIG. 1, reference numeral 1 is a rotary shaft made of ceramic pipe for feeding an inert gas for degassing, and a drive device (not shown) is provided at the upper end of the rotary shaft 1. Is connected to connector-2. Reference numeral 3 is a pipe-shaped gas discharger that is attached to the lower end of the rotary shaft 1 and discharges the gas supplied through the shaft 1 in the radial or downward direction of the processing container. And a gas injection part 5 also made of a ceramic pipe.

Here, the connector-2 is a connector as disclosed in Japanese Unexamined Patent Publication No. 2-85522, in which a female screw portion formed on a large diameter member and a small diameter screwed to the female screw portion. A connector for connecting a large-diameter member and a small-diameter member having a male screw portion provided on the outer periphery of the member.

Further, the gas discharger 3 has one of an L-shape, a T-shape, and a radial shape as shown in FIG. 2, and a joint portion 4 used by being attached to the rotary shaft 1 is used. And the gas ejection portion 5 provided at the extending position of the joint portion 4. This can be formed integrally or as a separate body. However, when it is formed as a separate body, it is desirable that the gas ejection portion 5 be detachable from the joint portion 4.

The gas ejection part 5 has one or more gas ejection ports 6 for ejecting in the radial direction or the direction toward the bottom part around the tip part thereof, and if this is the joint part. When it is detachably attached to 4, the length should be adjustable.

In use, the gas injector of the present invention configured as described above, as shown in FIG. 3, corresponds to the size of the processing container 7 and the swirl of the inner diameter X of the processing container 7 and the gas discharger 3. The ratio of the diameter Y to the range Y is in the range of 1: 0.2 to 1: 0.35, and the ratio of the swirling diameter Y of the gas discharger 3 to the pipe thickness Z of the gas ejection portion 5 is set to 1 The size is preferably in the range of 0.02 to 1: 0.2.

The reason for 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 inert gas bubbles to be ejected are This is because the dispersion becomes insufficient and the degassing efficiency deteriorates. On the other hand, when X is 1 and Y is larger than 0.35, or when Y is 1 and Z is larger than 0.2, it is against the melt. This is because the resistance increases and vortices are generated in the molten metal during processing, resulting in poor degassing efficiency.

As the ceramics used in the gas injector of the present invention, Si ₃ N _4, sialon, Si ₃ N ₄ group composite ceramics (eg BN + Si ₃ N ₄ or SiC + Si ₃ N ₄ ) are suitable. Is.

As described above, according to the gas injector having the above-described configuration according to the present invention, since the resistance is small, the eddy as shown in FIG. 4 is not generated, and the molten aluminum in the processing container is not generated. It is possible to uniformly and efficiently stir, and by degassing and removing non-metallic inclusions, a so-called clean molten aluminum can be produced.

The gas injector of the present invention can further improve the degassing efficiency by periodically changing the rotation direction by the driving device.

[0023]

【Example】

(Example) Using the gas injector according to the present invention made of Si ₃ N ₄ with the gas discharger at the lower end set at a position about 100 mm away from the bottom of the ladle (inner diameter 750 mmφ, depth 800 mm), 500 kg of molten aluminum contained in a ladle was rotationally bubbled for 5 minutes at 300 rpm, 0.1 to 1 kg / cm ² injection pressure, and 5 to 20 l / min. (0 ° C, 1 atm). It was possible to effectively remove hydrogen and non-metallic inclusions, and especially H ₂ gas could be reduced from 0.38 cc / 100g-Al to 0.10cc / 100g-Al.

Comparative Example A degassing process was carried out in the same manner as in the example except that the processing apparatus shown in FIG. 4 was used, and H ₂ gas was 0.38 cc / 100 g-Al to 0.25 cc / Only 100g-Al can be removed, and after further treatment for 15 minutes, it is reduced to 0.20cc / 100g-Al, and it is clear that the degassing efficiency is poor.

[0025]

[Effect of the device]

 As described above, the present invention enables efficient degassing without generating vortices in the molten metal by adopting a simple device configuration consisting only of ceramic pipes with low resistance to the molten metal. ..

Further, the device of the present invention does not require a dedicated processing container and can be applied to any container (hand-held furnace), and since the portion immersed in the molten metal is only a ceramic pipe, so-called It is far superior to the conventional device in terms of life. And, this device is advantageous in both manufacturing and maintenance in terms of price.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a gas injector of the present invention, (a) when the gas outlet is in a radial direction, and (b) when the gas outlet is oriented in a direction toward the bottom.

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

FIG. 3 is a view showing a usage state of the gas injector of the present invention.

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

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

[Code]

 1 Rotating Shaft 2 Connector 3 Gas Discharger 4 Joint 5 Gas Ejection 6 Gas Ejection 7 Processing Container 8 Rotor 9 Groove 10 Molten Metal 11 Baffle Plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C22B 9/05 (72) Creator Toshinori Matsuda 1-4-3-63 Ohama, Sakata City, Yamagata Prefecture Nippon Heavy Industries Ceramics Development Center Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A ceramic pipe rotary shaft having an upper end removably attached to a rotor portion of a drive unit;
And a ceramic pipe joint part attached to the lower end of the rotary shaft for discharging the gas supplied through the shaft into the molten metal of the processing container and a ceramic pipe gas jet in the extended position of the joint part. And an L-shaped, T-shaped, and radial pipe-shaped gas ejector, and an injector for a molten metal degassing device. 2. The ratio of the inner diameter of the processing container to the swirl diameter of the gas discharge body is set in the range of 1: 0.2 to 1: 0.35, and the swirl diameter of the gas discharge body and the gas ejection portion The injector for a molten metal degassing apparatus according to claim 1, wherein the ratio to the pipe thickness is set to a range of 1: 0.02 to 1: 0.2.