JPH0233780B2 - YOJUKINZOKUNOFUJUNBUTSUJOKYOYOKAITENNOZURU - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotary nozzle for removing impurities from molten metal, and more particularly to a rotary nozzle frequently used for degassing and removing inclusions from molten aluminum.

(Prior Art) In recent years, as the scope of use of aluminum products has expanded, there has been a demand for improved quality. In order to improve the quality of aluminum products, it is important to improve the quality of the ingot that is the raw material for the product, and high-quality ingots are made by removing hydrogen gas and inclusions from the molten metal during the melting and casting process. obtained by That is, by performing molten metal treatment for the purpose of degassing and removing inclusions, a high quality ingot can be obtained.

In other words, molten aluminum contains impurities such as hydrogen gas and inclusions such as oxides, which are generated during the melting process of raw materials, and when these impurities mix into the ingot, pinholes occur in the casting. In addition, surface defects such as blisters occur during hot working and intermediate annealing, resulting in poor mechanical properties and formability.
Characteristics such as processability and surface treatability will be deteriorated. Therefore, impurities are removed by the molten metal treatment.

Conventionally, as a method for treating molten aluminum, as shown in FIG. A gas bubbling method using a rotating nozzle is known in which, for example, inert gas is blown into the molten metal A in the form of fine bubbles D through an air supply passage (not shown) in which hydrogen gas and inclusions are floated and separated.

According to this molten metal processing method, inert gas bubbles D as fine as possible are dispersed and released into the molten aluminum metal A, and the molten metal A is appropriately stirred to actively bring the molten metal A and the bubbles D into contact with each other.
Removes impurities. Therefore, it is a major challenge in molten metal processing to disperse and release as fine inert gas bubbles D as possible into the molten metal A, and the impurity removal rotary nozzle B is suitable for dispersing and releasing the fine inert gas bubbles D. Various proposals have been made.

For example, as disclosed in Japanese Patent Publication No. 60-53092, a nozzle B made of a ceramic porous body attached to the lower surface of a disc-shaped main body has also been proposed. In addition, as shown in FIGS. 6 and 7, many of the current markets have shaft portion B1 and shaft portion B.
The rotor part B2 is provided at the lower part of the rotor part B2, and is made of carbon. and,
The inert gas sent from the air supply passage b1 formed along the axis of the shaft part B1 is transmitted to the rotor part B2.
It is emitted from the outlet b2 formed in the middle part of the radially formed grooves b3 and the outer circumferential notches b4 continuous to the outer ends of these grooves b3, and is pulverized and dispersed. The molten metal is stirred by the part b4.

(Problem to be solved by the invention) However, the conventional rotary nozzle B for removing impurities
For example, in the case of porous ceramics made of cordierite, they are easily damaged due to their low thermal shock strength, and in the case of porous ceramics made of cordierite,
Although there is no problem in heat resistance when used by immersing it in molten aluminum at temperatures exceeding 700°C, it has poor wear resistance and oxidation resistance and is short-lived. That is, even if a carbon rotary nozzle that has been subjected to oxidation-resistant treatment such as impregnated with phosphoric acid is used, the oxidation reaction continues and causes a large amount of wear, and the friction with the molten metal also causes a relatively large amount of wear. As a result, the rotating nozzle must be replaced more frequently, which not only reduces processing efficiency but also poses an economical disadvantage.

Therefore, it may be possible to form the rotating nozzle for removing impurities from dense ceramics (dense cordierite or dense zirconia) that have excellent wear resistance and oxidation resistance, but dense ceramics have extremely poor machinability and are difficult to shaft. It is quite difficult to process not only the external shapes of the portion B1 and the rotor portion B2, but also the air supply passage b1, the outlet b2, the radial groove b3, the outer peripheral notch b4, etc., and the cost is high.

Furthermore, the nozzle had various drawbacks in terms of its structure and stirring performance. In other words, in terms of structure, in the conventional rotary nozzle B for removing impurities, inert gas bubbles are pulverized by using the radial grooves b3 and the outer peripheral notch b4 formed in the rotor part B2. Therefore, the impurity removing rotary nozzle B must be rotated at a relatively high speed.

However, when the nozzle is rotated at high speed, it not only involves the oxide film on the hot water surface, but also disturbs the hot water surface and causes an increase in the amount of oxidation, and also causes the disadvantage that frictional force increases and wear increases. To this end, conventionally, the nozzle is rotated at a low speed to increase the flow rate of the inert gas to compensate for the miniaturization of the inert gas bubbles. Naturally, therefore, there is a problem in that the amount of gas consumed increases and the economic burden increases.

The present invention was developed in view of the above circumstances.Firstly, the material has excellent wear resistance and oxidation resistance, which extends the service life of the material.As a result, the frequency of replacement is significantly reduced and processing efficiency is improved. In addition to the development of materials that can improve the process, the structure of the nozzle has improved the ability to reduce purification gas under low-speed rotation by having excellent workability and dispersing and releasing fine purification gas (inert gas, etc.) bubbles. It is an object of the present invention to provide a rotary nozzle for removing impurities from molten metal, which has a structure capable of reducing consumption and can be realized at a low price.

(Means for Solving the Problem) In order to achieve the above object, the first aspect of the present invention
In the present invention, a rotary nozzle for removing impurities from molten metal is formed of porous silicon carbide and includes a shaft part and a rotor part, and a plurality of radially extending grooves are formed in the bottom wall of the rotor part. A plurality of small holes are provided through the bottom wall.

Further, in order to achieve the above object, a second invention according to the present invention is such that a rotary nozzle for removing impurities from molten metal is formed of porous silicon carbide and includes a shaft part and a rotor part, and The purification gas discharge portion is formed with a pore diameter larger than the pore diameter formed in the shaft portion and the rotor portion, respectively.
It is made of porous silicon carbide with a pore diameter in the 100 μm range.

(Function) According to the first invention, since wear resistance and oxidation resistance are improved, wear caused by friction with molten metal and wear caused by oxidation reaction with molten metal are suppressed, and life is extended. This greatly reduces the frequency of replacement, which improves the workability of removing impurities from molten metal.In addition, a plurality of radially extending grooves are formed on the bottom wall of the rotor section. Since the groove has a plurality of small holes penetrating the bottom wall, the molten metal can be stirred and dispersed evenly, reducing the amount of purifying gas consumed under low-speed rotation and efficiently removing impurities.

Further, according to the second invention, since wear resistance and oxidation resistance are improved, wear caused by friction with molten metal and wear caused by oxidation reaction with molten metal are suppressed, and life is extended. This has been achieved, significantly reducing the frequency of replacement, thereby improving the workability of impurity removal treatment of molten metal, and making it possible to improve the workability of removing impurities from molten metal. Since fine purifying gas bubbles can be dispersed and discharged from the purifying gas discharge part formed of high quality silicon carbide, the state of contact between the molten metal and the purifying gas bubbles is improved. Therefore, even when rotating at a low speed, the amount of purified gas consumed can be reduced.

In addition, if the pore diameter of the gas release part is less than 10 μm,
The function as the main release of inert gas bubbles is reduced,
On the other hand, if the pore diameter exceeds 100 μm, an excessive amount of inert gas will be generated and the amount consumed as purification gas will be excessive.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a partially sectional front view of a first embodiment of the present invention, and FIG. 2 is an enlarged bottom view. portion 10, and a large-diameter disk-shaped rotor portion 2 provided at the bottom of this shaft portion 10.
Each of them is made of SiC, that is, silicon carbide, and is formed of porous silicon carbide having air bubbles with a pore diameter of 0.1 to 100 μm.

The shaft portion 10 has a first passage 11 along the axis.
is formed through it, and the upper end connecting portion 12 is connected to the rotational drive system and the like through a coupling (not shown) or the like.
It is connected to a purification gas supply source (both not shown) made of an inert gas such as Ar, _N2 , He, or a mixed gas with chlorine.

A fitting recess 21 is formed in the upper part of the rotor part 20, into which the lower end of the shaft part 10 is press-fitted,
A female threaded portion 22 with a slightly smaller diameter is formed at a concentric position below this fitting recess 21, and a space portion 23 with a larger diameter is formed below the female threaded portion 22. A plurality of (for example, 8
A plurality of grooves 25 are formed on the lower surface of the bottom wall 23a of the space 23, and each groove 25 extends radially from the vicinity of the center and is continuous with the notch 24. Compatible bottom wall 23
By forming a plurality of small holes 26 at predetermined intervals in a, the space 23 and the groove 25 are communicated with each other. Air supply passage 2 with small hole 26
is formed. Further, the shaft portion 10 has a male threaded portion 13 formed at its lower end, and by screwing the male threaded portion 13 into the female threaded portion 22 of the rotor portion 20, the rotor portion can be integrated with the lower portion of the shaft portion 10. It has a specially designed structure.

That is, the purifying gas is released into the radial grooves 25 from the outlet of the air supply passage 2, that is, the plurality of small holes 26, and is pulverized by these grooves 25 and the notches 24 continuous to the outer ends of each groove 25. , it is dispersed and released into the molten metal as fine purified gas bubbles and floats to the surface. Then, by appropriately stirring the molten metal through the notch 24, the molten metal and purified gas bubbles are brought into active contact, and hydrogen gas and
Molten metal treatment is performed to remove inclusions such as oxides as impurities.

The rotary nozzle 1 for removing impurities has excellent wear resistance and oxidation resistance, and is inert to molten aluminum. Therefore, wear caused by friction with the molten metal and wear caused by oxidation reactions are suppressed, and life extension can be achieved. Therefore, the frequency of replacing the rotary nozzle 1 for removing impurities is significantly reduced, and maintenance can be omitted, which reduces the economic burden and improves molten metal processing workability.

In addition, since it has superior machinability compared to conventional dense ceramics, the shaft section 10 and rotor section 20 can be easily machined in accordance with desired design conditions, and it is extremely low cost. It has economic advantages.

A rotary nozzle 1 for removing impurities according to the present invention (external diameter of shaft part 60 mmφ) is installed in the processing apparatus shown in FIG.
The temperature of the molten aluminum when the conventional carbon rotary nozzle B for impurity removal (external diameter of the shaft part is 70 mmφ) is installed.
As a result of a comparative test under arbitrarily set conditions of 680 to 750℃, rotation speed 180 to 900r, p, m, and Ar gas flow rate 0 to 80/min, we found that carbon impurity removal rotation Nozzle B is 5mm after 17 hours of operation.
However, the rotary nozzle 1 for removing impurities according to the present invention did not show any wear during 50 hours of operation.

FIG. 3 is a partially sectional front view showing a second embodiment of the present invention, and FIG. 4 is a bottom view thereof. Note that the same or equivalent parts as those in the first invention will be described with the same reference numerals.

3 and 4, the rotary nozzle 1 for removing impurities has a shaft portion 10 made of porous silicon carbide similar to the first invention.
and a large-diameter disc-shaped rotor part 20 provided at the lower part of the shaft part 10. A first passage 11 is formed through the shaft portion 10 along the axis, and an upper end connecting portion 12 is connected to a rotational drive system and a purification gas supply source (both not shown) via a coupling (not shown) or the like. Ru.

A fitting recess 21 is formed in the upper part of the rotor part 20, into which the lower end of the shaft part 10 is press-fitted,
A female threaded portion 22 of a slightly smaller diameter is formed at a concentric position on the lower side of this fitting recess 21, and the lower side of the female threaded portion 22 is largely opened downward. A purified gas discharge section 3 is press-fitted into the lower end of this opening. The purified gas discharge section 3 is made of porous silicon carbide having pores 3a (10 to 100 μm) with a larger pore diameter than the shaft section 10 and the rotor section 20. This suppresses the release of purified gas from the center. Further, a space 23 is formed in the upper part of the purified gas discharge part 3, and the air supply passage 2 is formed by the first passage 11 of the shaft part 10, the space 23, and the large pores of the purified gas discharge part 3. . Similarly to the first invention, the shaft portion 10 has a male threaded portion 13 formed at its lower end.
The rotor part 20 is provided at the lower part of the shaft part 10 by screwing into the female thread part 22 of the rotor part 20, and a plurality of notches 24 are formed on the outer periphery of the rotor part 20. There is.

In the above configuration, the rotary nozzle 1 for removing impurities
is installed in the molten aluminum processing apparatus in the same manner as the first invention, and is immersed and rotated in the molten aluminum, and purifying gas is blown into the molten aluminum to disperse and release it into the molten aluminum.

That is, the purified gas is dispersed and released as fine purified gas bubbles from the purified gas discharge part 3 constituting the outlet of the air supply passage 2 and floats to the surface. Then, by appropriately stirring the molten metal through the cut holes 24, a swirling flow is given to the molten metal, and the purified gas microbubbles are mixed into this flow, and the purified gas bubbles remain there until they are discharged from the surface of the molten metal. A molten metal treatment is performed in which the purified gas bubbles are brought into active contact with the molten aluminum over time to remove inclusions such as hydrogen gas and oxides as impurities.

The rotary nozzle 1 for removing impurities has excellent wear resistance and oxidation resistance, and is inert to molten aluminum. Therefore, wear caused by friction with the molten metal and wear caused by oxidation reactions are suppressed, and life extension can be achieved. Therefore, the frequency of replacing the rotary nozzle 1 for removing impurities is significantly reduced, and maintenance can be omitted, which reduces the economic burden and improves processing efficiency.

Further, from the purified gas discharge part 3 formed of porous silicon carbide having pores 3a having a larger pore diameter than the shaft part 10 and the rotor part 20,
Since the purified gas can be dispersed and released as fine purified gas bubbles, the state of contact between the molten metal and the purified gas bubbles is good. Therefore, even if the rotary nozzle 1 for removing impurities is rotated at a low speed, there is no need to increase the flow rate of the purifying gas, so that the consumption amount of the purifying gas can be reduced.

Furthermore, since it has superior machinability compared to conventional dense ceramics, it is possible to easily process the shaft section 10 and rotor section 20 according to desired design conditions, and it is extremely low cost. It has economic advantages.

When the processing apparatus shown in FIG. 5 is equipped with the rotary nozzle 1 for removing impurities according to the present invention and when the rotary nozzle B for removing impurities made of conventional carbon is installed, the temperature of molten aluminum is 680 to 750.
℃, rotation speed 180~900r, p, m, Ar gas flow rate 0~
As a result of a comparative test under arbitrarily set conditions of 80/min, it was found that conventional impurity removal rotary nozzles require a rotation speed of 600r, p, m in order to obtain uniform and fine dispersion of Ar gas. , gas flow rate 8/
Although the impurity removal rotary nozzle 1 according to the second invention requires a rotation speed of 400 r,
Equivalent results could be obtained with p, m, and gas flow rate of 6/min.

In addition, although each of the above-mentioned Examples describes the removal of impurities from molten aluminum, the first and second inventions according to the present invention are not limited to the above-mentioned Examples, and may be applied to molten metals other than aluminum. Needless to say, this method can be applied to removing contaminated impurities.

(Effects of the Invention) As explained above, according to the first aspect of the present invention, the rotary nozzle for removing impurities from molten metal, which has a shaft part and a rotor part at the lower part of the shaft part, is made of porous silicon carbide. Since it is made of aluminum, wear resistance and oxidation resistance are improved. Therefore, wear caused by friction with the molten metal and wear caused by oxidation reaction with the molten metal can be suppressed, so the frequency of replacement of the impurity removing rotary nozzle is significantly reduced. Therefore, maintenance can be omitted, the economic burden can be reduced, and processing efficiency can be improved.

Furthermore, since it has superior machinability compared to dense ceramics, it can be easily processed to meet desired design conditions, and it has an economical advantage of being extremely low cost.

According to a second aspect of the present invention, a rotary nozzle for removing impurities from molten metal is formed of porous silicon carbide and has a shaft portion and a rotor portion provided at a lower part of the shaft portion, and The purifying gas discharge part is made of porous silicon carbide with pores having a pore diameter in the range of 10 to 100 μm, which is larger than the shaft part and the rotor part, so it has excellent wear resistance and oxidation resistance. Improves sex. Therefore, wear caused by friction with the molten metal and wear caused by oxidation reaction with the molten metal can be suppressed, and the frequency of replacement of the impurity removing rotary nozzle is significantly reduced. Therefore, maintenance can be omitted, the economic burden can be reduced, and processing efficiency can be improved.

In addition, the purified gas can be dispersed and released as fine purified gas bubbles from the purified gas discharge part formed of porous silicon carbide having pores larger than those of the shaft and rotor parts. Good contact between the molten metal and the purified gas bubbles is achieved. Therefore, even if the rotary nozzle for removing impurities is rotated at a low speed, there is no need to increase the flow rate of the purification gas, so the amount of purification gas consumed can be reduced.

Moreover, compared to dense ceramics, it has excellent machinability, so it can be easily processed to meet desired design conditions, and it is economically advantageous at an extremely low price. .

[Brief explanation of drawings]

FIG. 1 is a partially cross-sectional front view of a first embodiment of the present invention, FIG. 2 is an enlarged bottom view of the same,
Fig. 3 is a partially sectional front view of an embodiment of the second invention, Fig. 4 is an enlarged bottom view of the same, Fig. 5 is a schematic perspective view of a molten metal processing apparatus, and Fig. 6 is a conventional example. A front view partially shown in section, and FIG. 7 is an enlarged bottom view of the same. DESCRIPTION OF SYMBOLS 1...Rotary nozzle for impurity removal, 2...Air supply passage, 3...Purified gas discharge part, 3a...Bubble, 10
...Shaft part, 20...Rotor part.

Claims (1)

[Scope of Claims] 1. A shaft part and a rotor part provided at the lower part of the shaft part, which is immersed in molten metal and rotated to stir the molten metal, and an air supply formed in the shaft part and the rotor part. In a rotary nozzle for removing impurities from molten metal, in which purifying gas is blown into the molten metal through a passage and released in a dispersed manner, the shaft part and the rotor part are formed of porous silicon carbide, and the bottom wall of the rotor part has radial grooves. 1. A rotary nozzle for removing impurities from molten metal, characterized in that a plurality of elongated grooves are formed, and the grooves are provided with a plurality of small holes penetrating a bottom wall. 2. It is equipped with a shaft part and a rotor part provided at the lower part of the shaft part, and is immersed in molten metal and rotated to stir the molten metal, and at the same time blows purifying gas through an air supply passage formed in the shaft part and the rotor part. In a rotary nozzle for removing impurities from molten metal that is dispersed and discharged into molten metal, the shaft portion and the rotor portion are formed of porous silicon carbide, and a purified gas discharge portion on the lower surface of the rotor is connected to the shaft portion and the rotor portion, respectively. 1. A rotary nozzle for removing impurities from molten metal, characterized in that it is made of porous silicon carbide having pores with a pore diameter of 10 to 100 μm larger than the formed pore diameter.