JP7537703B2 - Gas inlet pipe - Google Patents

Description

The present invention relates to a gas injection tube that is immersed in molten metal in a molten metal container and injects gas into it.

Conventionally, gas injection has been performed by injecting an inert gas into the molten metal in order to eliminate gases such as oxygen and hydrogen that have become mixed into the molten metal. For example, a gas injection device for a holding furnace described in Patent Document 1, as a conventional example, is configured by installing a gas injection tube in a molten metal holding furnace and extending the tip of this gas injection tube to the vicinity of the bottom surface of the molten metal holding furnace. A porous blowing tool is connected to the tip of the gas injection tube. The inert gas flows into the holding furnace through the blowing tube and diffuses into the molten metal through the pores of the blowing tool. With this configuration, the inert gas physically adsorbs to the oxygen in the molten metal, rendering the oxygen inactive.

JP 4-200858 A

However, in the conventional example, the blowing tool is connected only to the tip of the gas blowing tube, so there is a risk that the blowing tool will fall off and be damaged by the gas pressure when the gas is blown in. In that case, there is a risk of bumping, in which gas is forcefully blown out from the tip. In addition, if pressure is applied inside the holding furnace, there is a risk of the molten metal flowing back into the gas blowing tube.

The object of the present invention is to provide a gas injection pipe that prevents bumping and prevents the molten metal from flowing back into the gas pipe.

The gas injection pipe according to the present invention is a gas injection pipe that is immersed in the molten metal in a molten metal container to inject gas, and includes a connection member having a first end and a second end, a porous member formed in the connection member, and a gas pipe connected to the second end of the connection member, the connection member having a through hole formed therein, the porous member covering the outer periphery of the first end connected to the first end, blocking the through hole facing the first end, and further formed so as to block at least a part of the inside of the through hole, the gas injection pipe is immersed in the molten metal in the molten metal container, and when the gas is introduced from the gas pipe, the gas is injected into the molten metal container through the porous member.

According to this, the porous member covers the outer periphery of the first end connected to the first end, blocks the through hole portion facing the first end, and is further formed so as to block at least a portion of the interior of the through hole portion. Since the gas blown into the molten metal passes through the porous member, the pressure is reduced and the occurrence of bumping can be prevented. In addition, since at least a portion of the interior of the through hole portion is provided with a porous member, the molten metal can be prevented from flowing back into the gas pipe even if the porous member of the first end portion falls off.

The gas inlet pipe may be configured such that the porous member is made of a first porous member and a second porous member, the first porous member covers the outer periphery of the first end connected to the first end and blocks the through hole portion facing the first end, and the second porous member blocks at least a portion of the inside of the through hole portion.

In this case, the porous member is divided into two components, and each can be easily formed into a connecting member independently. In addition, the first porous member and the second porous member can be formed into independent shapes, which increases the freedom in manufacturing.

The gas injection pipe may have a through hole portion, a space portion formed between the end face of the second porous member on the side of the first end portion and the end face of the first porous member on the side of the second end portion, and the gas injected through the gas pipe may pass through the second porous member, then through the space portion, and then through the first porous member, before being injected into the molten metal.

In this case, a space is formed in the gas injection tube. Since the space is not filled with a porous material, the amount of material equivalent to the volume of the space is reduced compared to when the space is filled with a porous material, and material costs can be reduced.

The first and second porous members of the gas inlet pipe may be made of the same material. In this case, by making the first and second porous members of the same material, material costs can be reduced and they can be manufactured using the same construction method.

The first and second porous members of the gas inlet pipe may be made of different materials. In this case, by making the first and second porous members arranged in series in the gas flow path from different materials, it is possible to take advantage of the characteristics of different porous materials on the downstream side, which is the gas inlet section, and the upstream side.

FIG. 2 is a diagram showing a state in which the gas blowing tube 1 of the present invention is immersed in a molten metal container 20. FIG. 1 shows a gas injection pipe 1a (11a, 12a) according to a first embodiment of the present invention, which has a space 6 inside a through hole 9, and (a) and (b) show a case in which the second end side of the through hole is filled with a second porous member, and (c) shows a case in which a recess 16 is formed in a portion of the second end side of the through hole without the second porous member. 1A and 1B are diagrams showing a gas injection pipe 1b (11b) according to a second embodiment of the present invention, in which there is no space 6 in the through-hole portion 9, where (a) shows a case in which the through-hole portion 9 is filled with a second porous member 23, and (b) shows a case in which the first porous member 13 is formed up to the inside of the through-hole portion 9, and the through-hole portion 9 is filled with the second porous member 23 and the first porous member 13. These figures show a gas injection pipe 1c (11c) according to a third embodiment of the present invention, in which the porous member 3 is formed as a single piece, with (a) showing the case in which the porous member 3 is made of a shaped refractory material, and (b) showing the case in which the porous member 3 is made of an unshaped refractory material. These figures show a gas injection pipe 1d (11d) according to a fourth embodiment of the present invention, in which the first porous member 13 and the second porous member 23 are formed of different materials, with (a) showing a case in which the second porous member is made of a molded refractory material and the first porous member is made of an amorphous refractory material, and (b) showing a case in which the second porous member is made of an amorphous refractory material or ceramic fiber and the first porous member is made of a molded refractory material. 3A and 3B are diagrams showing a manufacturing method of the gas inlet tube of the present invention in the cases shown in FIGS. 2(a) and 2(c). 4(a) and 4(b) in the gas inlet tube of the present invention. FIG. FIG. 1 is a diagram showing a conventional gas inlet pipe, in which only a member corresponding to a first porous member 13 is formed.

The gas injection pipe 1 embodying the present invention will be described below with reference to the drawings. The drawings are used to explain the technical features that can be adopted by the present invention. The configuration of the device shown in the drawings is not intended to be limiting, but is merely an illustrative example.

<Configuration common to each embodiment>
A configuration common to each embodiment of the gas blowing pipe 1 according to the present invention will be described with reference to Fig. 1 and Fig. 2. As shown in Fig. 1, the gas blowing pipe 1 according to the present invention is immersed in a molten metal 21 in a molten metal container 20 to blow in a gas 22.

As shown in FIG. 2 etc., the gas injection pipe 1 comprises a connection member 2 having a first end 7 and a second end 8, a porous member 3 formed in the connection member 2, and a gas pipe 4 connected to the second end 8 of the connection member 2. The connection member 2 has a through hole portion 9 formed therein. The porous member 3 covers the first end outer periphery 7a connected to the first end 7, blocks the through hole portion 9 facing the first end 7, and is formed so as to block at least a portion of the interior of the through hole portion 9.

The gas blowing tube 1 is immersed in the molten metal 21 in the molten metal container 20, and when gas 22 is introduced from the gas tube 4, the gas 22 is blown into the molten metal container 20 through the porous member 3. The gas 22 is, for example, argon gas or nitrogen gas. The molten metal 21 is, for example, made of a non-ferrous metal such as aluminum or copper. The porous member 3 may be formed of a single connected member, as described below, or may be formed as multiple separate members. The porous member 3 includes either a fixed refractory material such as ceramic fiber or fixed brick, or an unfixed refractory material such as castable.

Next, referring to FIG. 2 etc., a case where the porous member 3 is composed of a first porous member 13 and a second porous member 23 will be described. The first porous member 13 and the second porous member 23 are independent members. The first porous member 13 is formed so as to cover the first end outer periphery 7a connected to the first end 7 and to block the through hole portion 9 facing the first end 7. The second porous member 23 is formed so as to block at least a part of the inside of the through hole portion 9.

<Problems to be solved and effects common to each embodiment>
The gas blowing pipe 1 described above solves the following problems and has the following effects. In the conventional gas blowing pipe, as shown in Fig. 8, the blowing tool is connected only to the tip of the gas blowing pipe, so there is a risk that the blowing tool will fall off and be damaged by the gas pressure when blowing gas. In that case, there is a risk of bumping, in which gas is blown out forcefully from the tip. In addition, when pressure is applied inside the molten metal container, there is a risk of the molten metal flowing back into the gas blowing pipe.

In general, the hydrogen concentration in molten aluminum or copper can be reduced by injecting an inert gas such as argon or nitrogen into the molten metal. Furthermore, impurities such as oxides in the molten metal can be agglomerated by the gas bubbles and separated from the molten metal as slag, improving the performance of the metal. The equipment used for this degassing process is often a stirring type that injects gas bubbles into the metal from the tip of a rotating blade that rotates at high speed, but this is prone to equipment problems due to high speed rotation, and it is difficult to break down the bubbles when there is a large amount of gas.

The gas injection tube 1 of the present invention solves these problems. The gas 22 injected from the gas injection tube 1 into the molten metal 21 in the molten metal container 20 passes through the porous member 3, which allows the bubbles to be broken down into smaller pieces, improving degassing performance. The gas 22 also causes impurities such as oxides in the molten metal 21 to coagulate with the bubbles of the gas 22, allowing them to be separated as slag. Furthermore, the pressure of the gas 22 is reduced, which prevents bumping from occurring.

In addition, as shown in the example of FIG. 2, etc., at least a part of the through hole portion 9 is provided with a porous member 3 (in the example shown in FIG. 2, the second porous member 23 described later). Therefore, even if the porous member 3 around the first end portion 7 (in the example shown in FIG. 2, the first porous member 13 described later) falls off, the porous member 3 formed inside the through hole portion 9 (in the example shown in FIG. 2, the second porous member 23) acts as a breakwater. This prevents the molten metal 21 from flowing back into the gas pipe 4.

Furthermore, when the porous member 3 is composed of the first porous member 13 and the second porous member 23, the following effect is obtained. That is, since the gas injection pipe 1 has the first porous member 13 and the second porous member 23 formed in series, even if a defect such as falling off occurs in one, the other can compensate for its function. The function is to break down the bubbles of the gas 22 and inject them into the molten metal 21, and to prevent the molten metal 21 from flowing back into the gas pipe 4.

In addition, the gas injection pipe 1 blows the gas 22 from the gas pipe 4 through the second porous member 23, which is the porous member 3, and the first porous member 13 into the molten metal 21, so that the bubbles can be broken down. The gas 22 can improve the degassing performance. In addition, the effect of agglomerating impurities such as oxides in the molten metal 21 by the bubbles and separating them as slag can be further improved.

<Configuration of First Embodiment>
Next, the configuration of the gas blowing pipe 1a of the first embodiment according to the present invention will be described with reference to Fig. 2. Explanation of the common parts already described will be omitted. In the gas blowing pipe 1a, a space 6 is formed between an end face 23a of the through hole portion 9 on the side of the first end 7 of the second porous member 23 and an end face 13a on the side of the second end 8 of the first porous member 13. The gas 22 injected through the gas pipe 4 passes through the second porous member 23, the space 6, and then the first porous member 13 to be blown into the molten metal 21.

2(a) and (b) (gas inlet tube 1a and gas inlet tube 11a, respectively), the second porous member 23 is filled in the through hole portion 9 up to the second end 8 of the connection member 2. In contrast, in the example shown in FIG. 2(c) (gas inlet tube 12a), a recess 16 is formed between the end face 23b on the second end 8 side of the second porous member 23 and the second end 8 of the connection member 2. In the connection member 2 shown in FIG. 2 etc., a step 9a is formed in the through hole portion 9, and a space portion 6 is formed between the step 9a and the first end 7.

As already explained, when the porous member 3 is composed of the first porous member 13 and the second porous member 23, a step 9a is formed. The step 9a serves to hold the second porous member 23. That is, when the gas 22 is sent from the gas pipe 4 and reaches the second porous member 23, the gas 22 exerts a force to push the second porous member 23 toward the first end 7. At that time, if there is no step 9a and the through hole portion 9 is straight, there is no part of the second porous member 23 that receives the pressure of the gas 22, and it is possible that it will be pushed toward the first end 7. The difference between Figure 2(a) and Figure 2(b) will be described later.

Effects of the First Embodiment
The gas blowing pipe 1a of the first embodiment described above has the following advantages: The gas blowing pipe 1a can blow the gas 22 into the molten metal 21 at a stable pressure.

In addition to the effects common to each embodiment, the gas injection tube 1a has the effect of reducing material costs by forming the space 6. That is, since the space 6 is not filled with the porous member 3, the material equivalent to the volume of the space 6 is reduced compared to when the space 6 is filled with the porous member 3, and material costs can be reduced.

In addition, when the second porous member 23 is a standard refractory material, forming the space 6 has the effect of facilitating manufacturing. In the case of a standard refractory material, the second porous member 23 is molded in advance to match the internal shape of the through hole portion 9, but unevenness may occur on the end face 23a on the side of the first end portion 7. By forming the space 6, the end face 23a and the end face 13a on the side of the second end portion 8 of the first porous member 13 do not come into contact with each other, so even if unevenness occurs on the end face 23a, it is acceptable.

In addition, the following effect may be expected. The gas 22 passing through the gas pipe 4 enters the space 6 after passing through the second porous member 23, and is then blown into the molten metal 21 through the first porous member 13. The space 6 pools the gas 22 injected through the second porous member 23 and is maintained at a constant pressure. Then, the space 6 produces a damper effect that allows the gas 22 to be sent to the downstream first porous member 13 at a constant pressure even if the pressure of the gas 22 on the upstream side fluctuates. Therefore, the gas blowing pipe 1a can blow the gas 22 into the molten metal 21 at a stable pressure even if the pressure of the supply device that supplies the gas 22 fluctuates. Therefore, bumping that occurs when the pressure fluctuates and the gas 22 is blown in at high pressure can be prevented. The above effects are particularly expected when a large volume of gas 22 is blown in.

<Configuration of gas inlet pipe 1b in the second embodiment>

Next, the configuration of the gas blowing pipe 1b (11b) of the second embodiment according to the present invention will be described with reference to FIG. 3. In FIG. 3, components common to the gas blowing pipe 1a in FIG. 2 are given the same reference numerals or are omitted. Also, descriptions of the common components will be omitted.

At the first end 7 or inside the through hole 9 of the gas blowing pipe 1b, the second porous member 23 and the first porous member 13 come into contact with each other. The gas 22 injected through the gas pipe 4 passes through the second porous member 23 and then the first porous member 13, and is blown into the molten metal container 20. The second porous member 23 and the first porous member 13 may be in a state where the contacting surfaces are in close contact with each other with no gaps, or may be in partial contact with each other with partial gaps.

In the gas blowing tube 1b shown in FIG. 3(a), the through hole portion 9 of the connection member 2 is filled with the second porous member 23. The through hole portion 9 is filled with the second porous member 23 from the first end 7 to the second end 8 of the connection member 2, and contacts the first porous member 13 at the first end 7. In the gas blowing tube 11b shown in FIG. 3(b), the through hole portion 9 of the connection member 2 is filled with the second porous member 23 from the second end 8 to the step portion 9a of the connection member 2, and is filled with the first porous member 13 from the step portion 9a to the first end 7.

<Effects of the Second Embodiment>
The gas blowing pipe 1b of the second embodiment described above solves the following problems and provides the following effects: The gas blowing pipe 1b can blow the gas 22 into the molten metal 21 at a stable pressure, similar to the gas blowing pipe 1a.

The gas blowing pipe 1b (11b) is configured so that the second porous member 23 or the first porous member 13 continues over the entire length of the through hole portion 9 in the connection member 2 and up to the tip of the first end portion 7, which is the blowing portion of the gas 22. Therefore, the flow path of the gas 22 passing through the second porous member 23, which is the porous member 3, and the first porous member 13 becomes longer, and the pressure when blowing becomes more stable.

The through hole portion 9 of the gas injection pipe 1b (11b) may be filled with the second porous member 23, or with the second porous member 23 and the first porous member 13. In this case, the gas 22 passing through the through hole portion 9 always passes through either the first porous member 13 or the second porous member 23, so that the pressure when blown into the molten metal 21 in the molten metal container 20 becomes more stable.

<Configuration of Third Embodiment>
Next, the configuration of a gas blowing pipe 1c (11c) according to a third embodiment of the present invention will be described with reference to Fig. 4. The gas blowing pipe 1c (11c) differs from the gas blowing pipes 1a and 1b in that the porous member 3 is made of a single connected member.

In the example shown in FIG. 4(a), the porous member 3 is made of a molded refractory material, and mortar 14 is poured between the connecting member 2 and the porous member 3 to fix them without any gaps. In the example shown in FIG. 4(b), the porous member 3 is made of an unformed refractory material, and the connecting member 2 is set in a mold and the material is poured in to form it.

The gas injection tube 1c shown in FIG. 4(a) and the gas injection tube 11c shown in FIG. 4(b) are both formed so that the porous member 3 covers the outer periphery 7a of the first end portion connected to the first end portion 7, blocks the through hole portion 9 facing the first end portion 7, and further blocks the entire inside of the through hole portion 9.

The gas 22 blown into the molten metal 21 in the molten metal container 20 from the gas blowing pipe 1c and the gas blowing pipe 11c passes through the porous member 3, so the bubbles can be broken down and the degassing performance can be improved. In addition, impurities such as oxides in the molten metal 21 can be agglomerated by the gas 22 bubbles and separated as slag. Furthermore, the pressure of the gas 22 is reduced, so the occurrence of bumping can be prevented. In addition, since the porous member 3 is provided in the through hole portion 9, even if the porous member 3 around the first end portion 7 falls off due to a crack, the porous member 3 formed inside the through hole portion 9 acts as a breakwater. Therefore, the molten metal 21 can be prevented from flowing back.

<Effects of the First Porous Member and the Second Porous Member Made of the Same Material>
Next, a configuration and a manufacturing method in the case where the first porous member 13 and the second porous member 23 are made of the same material will be described. The examples shown in Fig. 2(a) and Fig. 2(c) show a case where the first porous member 13 and the second porous member 23 are both made of a fixed refractory material. In this case, the first porous member 13 and the second porous member 23 are made of the same material. Here, the same material indicates that the first porous member 13 and the second porous member 23 are both made of a fixed refractory material whose shape is fixed in advance, or both made of an unshaped refractory material. This also includes the case where they are made of the same raw material.

The examples shown in Figures 2(b) and 3 show the case where the second porous member 23 is formed of ceramic fiber or an unshaped refractory. When the first porous member 13 is formed of an unshaped refractory and the second porous member 23 is formed of an unshaped refractory, the first porous member 13 and the second porous member 23 are formed of the same material.

Next, referring to Figures 6 and 7, a manufacturing method for the gas injection pipe 1 when the first porous member 13 and the second porous member 23 are made of the same material will be described. As shown in Figure 6, when the first porous member 13 is a standard refractory material and the second porous member 23 is a standard refractory material, they are molded or processed in advance to match the shape of the portion to be formed in the connecting member 2, and then attached to the connecting member 2. At that time, mortar 14 is filled in the connecting portion between the connecting member 2 and the second porous member 23 and the first porous member 13 to bond them without gaps.

2, etc., the connecting member 2 uses a nipple or the like having male threads 7b, 8b formed on the first end 7 and second end 8, respectively. A female thread is formed in the gas pipe 4 in advance, and is screwed into the male thread 8b formed on the second end 8 of the connecting member 2. The connecting member 2 is not limited to a nipple shape, and any shape is acceptable as long as it is a member with a through hole portion 9. For example, a simple cylindrical member may be used, in which case the connection to the gas pipe 4 can be made by gluing, welding, or other methods. However, as already explained, when the porous member 3 is made of a first porous member 13 and a second porous member 23, a step portion 9a is formed in the through hole portion 9.

Next, as shown in FIG. 7, a case will be described in which the first porous member 13 is formed of an amorphous refractory material, and the second porous member 23 is formed of an amorphous refractory material or ceramic fiber. The second porous member 23 is formed by injecting amorphous refractory material or ceramic fiber into the through hole portion 9 of the connection member 2. On the other hand, the first porous member 13 is formed by producing a mold corresponding to the first end portion 7 of the connection member 2, and injecting amorphous refractory material with the first end portion 7 side of the connection member 2 attached to the mold. The connection between the connection member 2 and the gas pipe 4 is similar. Note that when the porous member 3 has the form shown in FIG. 4(a), it is formed in the same way as in the case shown in FIG. 7.

As explained above, when the first porous member 13 and the second porous member 23 are made of the same material, the costs of managing and arranging the materials can be reduced. In addition, when it is possible to mold it into a fixed shape in advance, such as with a standardized refractory material, it can be molded or processed into the required shape in advance and bonded to the connecting member 2 to form it. When ceramic fiber is used as a standardized material, it is handled in the same way as a standardized refractory material.

<The case where the first porous member and the second porous member are made of different materials and the effect thereof>
Next, a description will be given of a configuration and a manufacturing method in the case where the first porous member 13 and the second porous member 23 are made of different materials. As shown in Fig. 5, a gas blowing pipe 1d (11d) of the fourth embodiment shows a case where the first porous member 13 and the second porous member 23 are made of different materials. Here, the different materials indicate a case where one is a so-called fixed refractory material whose shape can be fixed in advance, and the other is an unshaped refractory material or ceramic fiber, but also includes a case where they are formed from different raw materials.

The gas injection pipe 1d shown in FIG. 5(a) shows a case where the second porous member 23 is made of a shaped refractory material and the first porous member 13 is made of an unshaped refractory material. The gas injection pipe 11d shown in FIG. 5(b) shows a case where the second porous member 23 is made of an unshaped refractory material or ceramic fiber and the first porous member 13 is made of a shaped refractory material. The manufacturing method for each has already been described.

When the first porous member 13 and the second porous member 23 are made of different materials, their respective properties can be made different. For example, the strength, weight, density, and even porosity of each member can be easily made different.

1, 1a, 1b, 1c, 1d, 11a, 11b, 11c, 11d, 12a Gas blowing tube 2 Connection member 3 Porous member 4 Gas tube 6 Space portion 7 First end portion 7a First end portion outer periphery 8 Second end portion 9 Through hole portion 13 First porous member 13a End surface 20 Molten metal container 21 Molten metal 22 Gas 23 Second porous member 23a End surface

Claims (5)

A gas injection pipe that is immersed in the molten metal in the molten metal container and injects gas into the molten metal,
a connecting member having a first end and a second end;
A porous member formed on the connection member;
a gas pipe connected to the second end of the connecting member;
The connection member has a through hole formed therein,
The porous member is
The first end portion is covered with a first end outer periphery connected to the first end portion, the through hole portion facing the first end portion is closed, and the through hole portion is further formed to close at least a part of the inside thereof,
a gas blowing pipe that is immersed in the molten metal in the molten metal container and blows the gas into the molten metal container through the porous member when the gas is introduced from the gas pipe; The porous member includes a first porous member and a second porous member,
The first porous member covers an outer circumferential portion of the first end portion connected to the first end portion and closes the through-hole portion facing the first end portion,
The gas blowing pipe according to claim 1 , wherein the second porous member blocks at least a part of the inside of the through hole portion. The through-hole portion has a space formed between an end face of the second porous member on the side of the first end portion and an end face of the first porous member on the side of the second end portion,
3. The gas injection pipe according to claim 2, wherein the gas injected through the gas pipe passes through the second porous member, the space, and the first porous member before being injected into the molten metal. The gas injection pipe according to claim 2 or 3, wherein the first porous member and the second porous member are made of the same material. 4. The gas injector pipe according to claim 2, wherein the first porous member and the second porous member are made of different materials.

Images