JP2021062387A - Apparatus for melt casting - Google Patents

Abstract

To provide an apparatus for melt casting capable of hermetically sealing a mold to prevent the quality degradation of an ingot.SOLUTION: An apparatus for melt casting comprises a lid member 40 that can open/close an upper opening 16a of a mold 16 in which a molten metal is reserved. Within the lid member 40, a gas passage 54 is formed for an inert gas to be supplied from a gas supply source 56. In the lid member 40, a gas ejection port 54a is formed communicating with the gas passage 54 and opening at a lower side. Before closing the upper opening 16a of the mold 16 by the lid member 40, splashes adhered on a seal surface 16b are removed by an inert gas ejected from the gas ejection port 54a toward the seal surface 16b due to the lid member 40 in the mold 16.SELECTED DRAWING: Figure 6

Description

The present invention relates to a melting and casting apparatus that melts and solidifies a metal to produce an ingot.

The vacuum arc melting device disclosed in Patent Document 1, for example, is preferably used as a melting and casting device for producing an ingot by melting and solidifying an active metal such as titanium or a titanium alloy. In the vacuum arc melting device, a consumable electrode made of metal to be melted is suspended in the chamber, and the mold is connected to the lower part of the chamber so as to communicate with each other to maintain the inside of the chamber and the mold in a vacuum atmosphere. , An arc is generated between the consumable electrode and the mold, and the consumable electrode is melted by the arc heat. The melted consumable electrode becomes droplets and drops into the mold, and is sequentially solidified to obtain an ingot. Then, the ingot in the mold is taken out after being cooled to a predetermined temperature.

In the vacuum arc melting device, two molds are arranged apart from each other, a chamber is communicated with one mold to melt a consumable electrode, and a melting step of forming an ingot is performed in the mold, and the melting step is completed. While the upper opening of the mold is closed with a lid member to maintain a vacuum atmosphere inside and cool, the chamber moved above the other mold is communicated with the mold to perform a melting process. Improving capabilities is being done.

Japanese Unexamined Patent Publication No. 5-230559

After the completion of the melting step, if the ingot solidified in the mold is cooled to the atmosphere at a high temperature, it is oxidized and the quality deteriorates. Therefore, the inside of the mold is kept in the air until the temperature is such that the quality of the ingot does not deteriorate even by atmospheric cooling. It is important not to have an atmosphere. However, during the melting process, splashes (splashes of molten metal) scattered from the consumable electrode and the molten metal (molten metal) stored in the mold may adhere to the sealing surface with the lid member in the mold, and the sealing surface may adhere to the sealing surface. Even if the upper opening of the mold is closed by the lid member with the splash attached, it cannot be sealed, the inside of the mold cannot be maintained at a predetermined degree of vacuum, and the ingot is oxidized and the quality deteriorates. There is a problem to do. Further, the lid member and the mold are configured to be sealed by a sealing material such as an O-ring, but if the sealing material comes into contact with the splash and burns out, the degree of sealing is lowered and the ingot is oxidized. Problems are also pointed out.

That is, the present invention has been proposed in view of the above-mentioned problems inherent in the above-mentioned prior art, and has been proposed to preferably solve the above-mentioned problems, and melt casting capable of sealing the mold to prevent deterioration of the quality of the ingot. The purpose is to provide the device.

In order to overcome the above-mentioned problems and achieve the desired object, the melting and casting apparatus according to the invention of claim 1 is used.
The lid includes a mold (16) having an opening (16a) and storing molten metal, and a lid member (40) capable of opening and closing the opening (16a) of the mold (16). The member (40) is a melting and casting apparatus having a sealing material (52) that abuts on the sealing surface (16b) of the mold (16) surrounding the opening (16a) when the opening (16a) is closed. There,
A gas passage (54) formed inside the lid member (40) and
A gas injection hole (54a) formed in the lid member (40) so as to communicate with the gas passage (54) and open on the lower surface side of the lid member (40).
The gas passage (54) is provided with a gas supply source (56) for supplying an inert gas.
When the opening (16a) of the mold (16) is closed by the lid member (40), the sealing material (52) uses the inert gas supplied to the gas passage (54) to seal the surface (16b). ), The gist is that the gas is injected from the gas injection hole (54a) toward the sealing surface (16b).
In the invention of claim 1, the splash adhering to the sealing surface with the lid member in the mold can be removed by the inert gas injected from the lid member, and the mold can be sealed by the lid member. That is, it is possible to prevent the inside of the mold from becoming an atmospheric atmosphere, and it is possible to prevent the quality of the ingot from deteriorating. In addition, it is possible to prevent the sealing material from coming into contact with the splash and burning out, thereby preventing the degree of sealing from being lowered.

It is a gist of the invention of claim 2 that a plurality of the gas injection holes (54a) are provided apart from each other in the circumferential direction of the lid member (40).
In the invention of claim 2, the splash adhering to the sealing surface can be effectively removed by the inert gas injected from the plurality of gas injection holes.

According to the third aspect of the present invention, the gas injection hole (54a) is a state in which the opening (16a) of the mold (16) is closed by the lid member (40), and the inert gas is placed in the mold (16). It is provided at a position where it can be sprayed.
The gist is that the inside of the mold (16) is made to have an atmosphere of an inert gas injected from the gas injection hole (54a) so that the ingot in which the molten metal is solidified can be cooled.
In the invention of claim 3, the ingot can be cooled by setting the inside of the mold as an inert gas atmosphere, and the ingot can be prevented from being oxidized.

In the invention of claim 4, the water path (60) is formed inside the lid member (40), and the cooling water circulates between the water path (60) and the cooling water supply source (62). Configured
The water passage (60) is composed of a plurality of chambers (66a, 66b, 66c, 66d, 66e, 66f, 66g) communicating with each other, and the cooling water introduced from the inlet (60a) is composed of a plurality of chambers (66a, 66e, 66f, 66g). The gist is that the entire lid member (40) can be cooled by being discharged from the outlet (60b) around 66a, 66b, 66c, 66d, 66e, 66f, 66g).
In the invention of claim 4, the lid member can be cooled by the cooling water, the lid member can be prevented from being thermally deformed by the radiant heat from the ingot, and the degree of sealing of the mold can be prevented from being lowered. Further, since the cooling water introduced into the lid member is configured to go around the entire lid member, it is possible to suitably prevent the lid member from being partially thermally deformed due to uneven cooling by the cooling water.

According to the melt casting apparatus according to the present invention, the mold can be sealed by the lid member to cool the ingot, and the quality of the ingot can be prevented from deteriorating.

It is the schematic which shows the vacuum arc melting apparatus which concerns on Example. It is the schematic plan view which shows the installation part of the mold which concerns on Example by partially breaking. It is the schematic which shows the lid device which concerns on Example. It is a cross-sectional plan view of the lid member which concerns on embodiment, and shows a gas passage. It is a cross-sectional plan view of the lid member which concerns on an Example, and shows a water path. It is a main part vertical sectional view which shows the state before closing the mold which concerns on Example with a lid member. It is a vertical cross-sectional view of a main part which shows the state which the mold which concerns on Example is closed with a lid member.

Next, the melt casting apparatus according to the present invention will be described below with reference to the accompanying drawings with reference to suitable examples. In the embodiment, as the melting and casting apparatus, a vacuum arc melting apparatus for melting a metal and producing an ingot by using a vacuum arc melting method (VAR method) will be described as an example.

FIG. 1 shows a vacuum arc melting device according to an embodiment, in which the vacuum arc melting device has an upper chamber 10 and a consumable electrode 12 made of a metal such as titanium or a titanium alloy to be melted in the upper chamber 10. A support device 14 that hangs and moves up and down, and a plurality of (two in the embodiment) installation portions 18 and 18 for storing a molten consumable electrode (molten metal) and installing a mold 16 for obtaining an ingot are provided. The upper chamber 10 is a tubular container whose upper part is closed and whose lower part is open, and is supported by a carriage 22 which can move along the rail 20 and is installed in either of the two installation portions 18 and 18. It is configured to be movable above the molded mold 16. Further, the support device 14 includes a stinger rod 26 suspended above the upper chamber 10 so as to be movable up and down via an airtight seal 24, and an elevating device 28 provided on the carriage 22 to move the stinger rod 26 up and down. The consumable electrode 12 is connected to the lower part of the stinger rod 26 via the stub 30.

Each of the installation portions 18 is provided with a lower chamber 32 having an open upper portion, and the lower chamber 32 is connected to the vacuum pump 38 via an exhaust pipe 34 and an electromagnetic control valve 36 as shown in FIG. By operating the vacuum pump 38 in a state where the upper chamber 10 and the lower chamber 32 are communicated with each other and sealed, the insides of both chambers 10 and 32 can be created as a vacuum atmosphere. As shown in FIGS. 1 and 3, the mold 16 is configured so that the upper portion is open, and the upper opening (opening) 16a of the mold 16 is located in the lower chamber 32 in the installation portion 18. It is installed detachably. That is, the mold 16 is configured to communicate with the upper and lower chambers 10 and 32 via the upper opening 16a, and the inside of the mold 16 can be created as a vacuum atmosphere by operating the vacuum pump 38. .. The consumable electrode 12 is connected to the − terminal of the power supply device (not shown) via the stinger rod 26 and the elevating device 28, and the mold 16 is connected to the + terminal of the power supply device. Then, by supplying a predetermined voltage and a predetermined current between the consumable electrode 12 and the mold 16 from the power supply device, the consumable electrode 12 is melted by the arc heat generated between the consumable electrode 12 and the mold 16. The consumable electrodes melted in the mold 16 form a pool, and are sequentially cooled and solidified from the surroundings to obtain a predetermined ingot. The stinger rod 26 is moved up and down by the elevating device 28, and the consumable electrode 12 and the mold 16 are generated so that an arc is stably generated between the consumable electrode 12 and the mold 16 or the molten metal stored in the mold 16. Alternatively, it is configured to maintain a distance from the molten metal.

As shown in FIGS. 2 and 3, a lid device 42 provided with a lid member 40 capable of opening and closing the upper opening 16a of the mold 16 installed in each of the installation portions 18 is provided. The lid device 42 has a lid member 40 at an upper position of the upper opening 16a of the mold 16 (two-dot chain line position in FIG. 3) and a retracted position (the installation portion 18 on the left side of FIG. 2) that separates the lid member 40 laterally from the upper position. The moving means 44 that moves between the moving means 44 and the lid member 40, and the raising and lowering means 46 that moves the lid member 40 up and down between the upper position and the lower closed position (solid line position in FIG. 3) above the mold 16. By lowering the lid member 40 at the upper position to the closing position, the lid member 40 is configured to close the upper opening 16a of the mold 16. The lid member 40 is configured to move the retracted position, the upper position, and the closed position inside the lower chamber 32, and the mold 16 is formed in a state where the upper chamber 10 and the lower chamber 32 are communicated with each other. The upper opening 16a can be closed without opening to the atmosphere.

As shown in FIGS. 6 and 7, a tapered seal surface 16b whose diameter decreases upward is formed on the upper outer circumference of the mold 16 so as to surround the upper opening 16a, and the seal surface 16b is said to have a tapered seal surface 16b. It is configured to be sealed by the lid member 40. Further, the lid member 40 is provided with an annular projecting portion 50 projecting downward on the lower surface of the main body 48 formed in a substantially disk shape, and a taper of the sealing surface 16b of the mold 16 is provided on the inner circumference of the projecting portion 50. A tapered surface 50a corresponding to the above is formed. Further, a sealing material 52 such as an O-ring is provided on the tapered surface 50a of the protruding portion 50 over the entire circumference. Then, by bringing the lid member 40 close to the mold 16 so that the sealing surface 16b of the mold 16 and the tapered surface 50a of the protruding portion 50 face each other, the sealing material 52 covers the entire circumference of the sealing surface 16b of the mold 16. It is configured so that the mold 16 can be sealed by contacting the mold 16. In a state where the sealing material 52 is in contact with the sealing surface 16b of the mold 16, a gap is formed between the tapered surface 50a and the sealing surface 16b inside the arrangement position of the sealing material 52. Has been done.

As shown in FIGS. 4, 6 and 7, a gas passage 54 is formed inside the main body 48 of the lid member 40, and the main body 48 communicates with the gas passage 54 and opens on the lower surface side. The injection hole 54a is formed. A plurality of gas injection holes 54a (10 in the embodiment) are formed at regular intervals in the circumferential direction of the main body 48, and the gas injection holes 54a are formed of the sealing material 52 provided on the tapered surface 50a. It is opened by a tapered surface 50a on the inner side in the radial direction from the arrangement position. Specifically, as shown in FIG. 6, the gas injection hole 54a faces the seal surface 16b of the mold 16 with the tapered surface 50a of the lid member 40 facing away from the seal surface 16b of the mold 16. In addition, with the lid member 40 closing the upper opening 16a of the mold 16, the lid member 40 is provided at a position where a gap S is formed between the sealing surface 16b and the tapered surface 50a, as shown in FIG. Further, a gas supply source 56 for an inert gas such as argon gas or nitrogen gas is connected to the gas passage 54 via a gas supply pipe 57 and an electromagnetic control valve 58. The gas passage 54 is formed in a radial direction extending radially from the connection port 54b with the gas supply source 56, and the outlet of each radial passage is a gas injection hole 54a, which is supplied from the gas supply source 56. The inert gas is injected downward from the plurality of gas injection holes 54a. When the upper opening 16a of the mold 16 is closed by the lid member 40, the electromagnetic control valve 58 is opened before the sealing material 52 abuts on the sealing surface 16b of the mold 16 to reach the sealing surface 16b. The inert gas is configured to be injected toward the gas injection hole 54a. Further, the electromagnetic control valve 58 is closed when the lid member 40 is moved from the closed position to the upper position to open the upper opening 16a of the mold 16 to stop the injection of the inert gas.

As shown in FIGS. 5 and 6, a water path 60 for circulating cooling water is formed inside the main body 48 of the lid member 40 above the gas passage 54. A water supply source 62, which is a supply source of cooling water, is connected to the cooling water inlet 60a in the water path 60 via a circulation pump 64, and a cooling water outlet 60b in the water path 60 is connected to the water supply source 62. By operating the circulation pump 64, the cooling water is configured to circulate between the water supply source 62 and the water path 60. The circulation pump 64 is always operated during the operation of the vacuum arc melting device, and is configured to circulate the cooling water at any of the retracted position, the upper position, and the closed position of the lid member 40.

As shown in FIG. 5, the water path 60 is composed of a plurality of chambers 66a, 66b, 66c, 66d, 66e, 66f, 66g communicating with each other so that the inlet 60a communicates with one of the chambers 66a. At the same time, the outlet 60b is formed so as to communicate with the other one chamber 66g. In the embodiment, the water path 60 is composed of seven chambers 66a, 66b, 66c, 66d, 66e, 66f, 66g, from the first chamber 66a with which the inlet 60a communicates to the seventh chamber 66g with which the outlet 60b communicates. The cooling water introduced into the first room 66a circulates in the order of the second room 66b → the third room 66c → the fourth room 66d → the fifth room 66e → the sixth room 66f → the seventh room 66g and exits. It is configured to return from 60b to the water supply source 62. More specifically, each of the chambers 66a, 66b, 66c, 66d, 66e, 66f, 66g extends in the radial direction of the main body 48 and partitions the first chamber 66a and the seventh chamber 66g so as not to directly communicate with each other. It is defined by the first partition member 68 and a plurality of second partition members 70 extending in a direction intersecting the first partition member 68, and is introduced into the first chamber 66a from the entrance 60a. The communication part of each room 66a, 66b, 66c, 66d, 66e, 66f, 66g is connected so that the cooling water meanders and circulates through each room 66b, 66c, 66d, 66e, 66f in order to reach the seventh room 66g. It is set so that the cooling water introduced from the inlet 60a goes around the entire main body 48 (lid member 40) and then is discharged from the outlet 60b.

As shown in FIG. 6, on the lower surface of the main body 48 of the lid member 40, a heat shield plate 72 is provided inward in the radial direction from the protrusion 50, separated downward, and the lid member 40 is the upper portion of the mold 16. With the opening 16a closed, the heat shield plate 72 is configured to prevent the radiant heat from the ingot from directly acting on the main body 48.

[Action of Example]
Next, the operation of the vacuum arc melting device of the embodiment configured as described above will be described.

In the vacuum arc melting device, the trolley 22 is moved to position the upper chamber 10 above one lower chamber 32, and the upper chamber 10 and the lower chamber 32 are communicatively connected and sealed, and then the vacuum is formed. The pump 38 is operated to create a vacuum atmosphere inside the lower chamber 32, the upper chamber 10 and the mold 16. By supplying a predetermined voltage and current to the consumable electrode 12 from the power supply device, an arc is generated between the consumable electrode 12 and the mold 16 or the molten metal, and the consumable electrode 12 is melted by the arc heat to form the mold 16. The stored molten metal gradually solidifies.

The consumable electrode 12 is moved up and down by the elevating device 28 so that an appropriate arc is generated between the consumable electrode 12 that melts from the lower end and the mold 16 or the molten metal. To end the melting process.

In the vacuum arc melting device of the embodiment, the lid member 40 located in the lower chamber 32 is moved from the retracted position to the upper position by the moving means 44 of the lid device 42 while maintaining the inside of the lower chamber 32 in a vacuum atmosphere. After that, the lid member 40 is lowered by the elevating means 46, and the electromagnetic control valve 58 is opened to supply the inert gas from the gas supply source 56 to the gas passage 54. That is, as shown in FIG. 6, at a position where the tapered surface 50a of the lid member 40 is separated upward from the sealing surface 16b of the mold 16, the inert gas injected downward from each of the gas injection holes 54a is emitted. The splash that is sprayed on the sealing surface 16b of the mold 16 and adheres to the sealing surface 16b in the melting step is blown off and removed. Then, when the lid member 40 is lowered to the closed position by the elevating means 46, the sealing material 52 provided on the tapered surface 50a of the lid member 40 is brought into contact with the sealing surface 16b of the mold 16 from which the splash has been removed. , The mold 16 is sealed (see FIG. 7).

Here, when the injection pressure of the inert gas injected from the gas injection hole 54a is, for example, 4.0 to 5.0 kg / cm ² , the circumference of the lid member 40 having a diameter of 670 mm is about 650 mm. If a gas injection hole 54a having a diameter of 4.5 mm is formed in the gas injection hole 54a and the distance between the gas injection holes 54a adjacent to each other in the circumferential direction is 200 mm, the height from the gas injection hole 54a to the sealing surface 16b of the mold 16 is 250 mm. It has been confirmed that all the splashes adhering to the sealing surface 16b can be removed by starting the injection of the inert gas from the position of.

As shown in FIG. 7, the gas injection hole 54a is configured so as not to be blocked by the sealing surface 16b of the mold 16 at the closed position of the lid member 40, so that the supply of the inert gas from the gas supply source 56 is continued. By doing so, the inside of the mold 16 becomes an inert gas atmosphere. Further, cooling water circulates in the water path 60 of the lid member 40, and the lid member 40 is cooled.

After sealing the mold 16 with the lid member 40, the connection between the upper chamber 10 and the lower chamber 32 is released, and a new consumable electrode 12 is connected to the stinger rod 26 via the stub 30. Then, the carriage 22 is moved to connect the upper chamber 10 to the mold 16 installed in the other installation portion 18, and the insides of the upper chamber 10, the lower chamber 32, and the mold 16 are maintained in a vacuum atmosphere as described above. Then, a new melting step of the consumable electrode 12 is performed.

In the vacuum arc melting device of the embodiment, the splash adhering to the seal surface 16b of the mold 16 can be removed by the inert gas injected from the gas injection hole 54a of the lid member 40, so that the mold 16 is removed by the lid member 40. Can be sealed. That is, it is possible to prevent oxidation of the ingot solidified in the mold 16 and improve the quality of the ingot. Further, since a plurality of gas injection holes 54a are provided apart from each other in the circumferential direction of the lid member 40, the splash adhering to the seal surface 16b of the mold 16 is effectively removed by the inert gas injected from the gas injection holes 54a. can do. Further, since the mold 16 is configured to cool the ingot by maintaining the inside of the mold 16 in an inert gas atmosphere by using the inert gas that removes the splash, the surface oxidation of the ingot can be further suppressed.

Since the vacuum arc melting device of the embodiment is configured to cool the lid member 40 with cooling water, it is possible to prevent the lid member 40 from being thermally deformed by radiant heat from the ingot and maintain a high degree of sealing of the mold 16. Can be done. Further, the water path 60 of the lid member 40 is configured so that the cooling water introduced from the inlet 60a circulates around the entire main body 48 (lid member 40) and is discharged from the outlet 60b. It is possible to preferably prevent the main body 48 (lid member 40) from being partially thermally deformed due to the uneven cooling. In the vacuum arc melting device of the embodiment, cooling water is constantly circulated and cooled in the lid member 40 located inside the lower chamber 32, so that the lid member 40 is heated by radiant heat from the ingot or the molten metal in the melting step. Can also be suppressed from thermal deformation.

Further, since the lid member 40 is provided with the heat shield plate 72 separated from the lower surface of the main body 48, it is more preferable that the main body 48 is thermally deformed by blocking the radiant heat from the ingot by the heat shield plate 72. Can be prevented. Since the heat shield plate 72 is a member that has nothing to do with the structure that seals the mold 16, even if the heat shield plate 72 is thermally deformed, the degree of sealing of the mold 16 does not decrease. Further, the heat shield plate 72 can be attached to and detached from the main body 48, and when the heat shield plate 72 is thermally deformed, it can be dealt with by replacing only the heat shield plate 72.

[Change example]
The present application is not limited to the configuration of the above-described embodiment, and other configurations may be appropriately adopted.
1. 1. In the embodiment, the case of a vacuum arc melting device in which the consumable electrode is melted by an arc generated between the consumable electrode made of metal and the mold or the molten metal as the melting and casting device has been described. It may be a vacuum induction melting apparatus which heats and melts by induction and casts the molten metal into a mold. In the vacuum induction melting device, if a crucible and a mold are installed in a casting chamber that can create a vacuum atmosphere, and the upper opening of the mold in which the molten metal is cast is closed by a lid member in the casting chamber, the casting chamber can be formed. Even if the crucible is opened to the atmosphere and a new metal raw material is supplied to the crucible, it is possible to prevent the ingot in the mold from being oxidized. Further, the splash adhering to the sealing surface of the mold in the step of casting the molten metal from the crucible to the mold can be removed by the inert gas injected from the lid member, and the mold can be sealed.
2. In the embodiment, two molds are used to alternately produce ingots, but if one mold is used and the molds are sealed with a lid member, the ingots can be cooled to a temperature at which the quality does not deteriorate even by atmospheric cooling. Before the temperature is lowered, the consumable electrode can be set on the upper chamber, and the cycle time can be shortened.
3. 3. The number, diameter, circumferential spacing, etc. of the gas injection holes formed in the lid member are not limited to the examples, and may be set according to the size of the lid member, and the sealing surface of the mold may be used. It suffices if the number, diameter and interval are such that the inert gas can be sprayed all around the circumference to remove all the splashes.
4. The number of chambers forming the water path formed in the lid member is not limited to seven, and the entire lid member is efficiently used until the cooling water introduced from the inlet is discharged from the outlet. Any number may be used as long as it can be cooled.

16 mold, 16a upper opening (opening), 16b sealing surface, 40 lid member 52 sealing material, 54 gas passage, 54a gas injection hole, 56 gas supply source 60 water path, 60a inlet, 60b outlet, 62 water supply source (supply source)

Claims (4)

A mold having an opening and storing molten metal and a lid member capable of opening and closing the opening of the mold are provided, and the lid member has the opening when the opening is closed. A melt casting device having a sealing material that comes into contact with the sealing surface of the mold surrounding the mold.
A gas passage formed inside the lid member and
A gas injection hole formed in the lid member so as to communicate with the gas passage and open on the lower surface side of the lid member.
The gas passage is provided with a gas supply source for supplying an inert gas.
When the opening of the mold is closed by the lid member, the inert gas supplied to the gas passage is injected from the gas injection hole toward the sealing surface before the sealing material comes into contact with the sealing surface. A melt casting apparatus characterized in that it is configured as The melting and casting apparatus according to claim 1, wherein a plurality of the gas injection holes are provided apart from each other in the circumferential direction of the lid member. The gas injection hole is provided at a position where the inert gas can be injected into the mold with the opening of the mold closed by the lid member.
The melting and casting apparatus according to claim 1 or 2, wherein the inside of the mold is made into an atmosphere of an inert gas injected from the gas injection hole so that the ingot in which the molten metal is solidified can be cooled. A water path is formed inside the lid member, and the cooling water is configured to circulate between the water path and the cooling water supply source.
The water path is composed of a plurality of chambers communicating with each other, and the cooling water introduced from the inlet is discharged from the outlet through the plurality of chambers so as to be able to cool the entire lid member. The melt casting apparatus according to any one of claims 1 to 3.

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