JP2010125513A - Centrifugal casting apparatus and centrifugal casting method for amorphous alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal casting apparatus which can produce an amorphous alloy having excellent shape precision, and to provide a centrifugal casting method for an amorphous alloy. <P>SOLUTION: The centrifugal casting apparatus 10 casting an amorphous alloy comprises: a casting mold 15 having a cavity part 17 at the inside and composed of an insulator; a mold rotating means 19 rotating the casting mold; a molten metal feeding means 13 feeding the molten metal of an amorphous alloy material to the casting mold; and an induction heating means 21 arranged in the vicinity of the casting mold. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a centrifugal casting apparatus and an amorphous alloy centrifugal casting method.

2. Description of the Related Art Conventionally, a method of manufacturing an amorphous alloy casting using a centrifugal casting apparatus is known. Such a centrifugal casting apparatus manufactures a molded body of an amorphous alloy having a desired shape by rotating a mold at a predetermined number of revolutions and pouring a melt of the amorphous alloy into a cavity formed in the mold. (See, for example, Patent Document 1). Further, in order to produce a molded body of an amorphous alloy so as not to crystallize, it is necessary to rapidly cool and solidify the molten amorphous alloy material supplied into the cavity.
JP 2008-126313 A

By the way, in a conventional centrifugal casting apparatus such as the centrifugal casting apparatus of Patent Document 1 described above, a temperature control mechanism cannot be provided in the mold in order to rotate the mold at a high speed. Therefore, in order to cool the molten metal of the amorphous alloy material, it is cooled by the mold, but the cooling capacity varies greatly depending on the thermal conductivity of the mold itself.
For this reason, as shown in the above-mentioned Patent Document 1, when a material having high thermal conductivity such as copper is used for the mold, the cooling rate is too high when the molten amorphous alloy is poured into the cavity. Therefore, before filling the entire cavity with the molten amorphous alloy material, the molten metal solidifies, so-called filling failure occurs, and it is impossible to produce an amorphous alloy casting of a desired shape, that is, shape accuracy There is a problem of getting worse. This is particularly noticeable in the production of an amorphous alloy casting having a thin-walled portion.

  Therefore, the present invention has been made in view of the above-described circumstances, and provides a centrifugal casting apparatus and a method for centrifugal casting of an amorphous alloy capable of producing a cast of an amorphous alloy having excellent shape accuracy. To do.

In order to solve the above problems, a centrifugal casting apparatus according to the present invention is a centrifugal casting apparatus for casting an amorphous alloy, a casting mold made of an insulator having a cavity portion therein, and a mold for rotating the casting mold. It is characterized by comprising rotating means, molten metal supply means for supplying a molten metal of the amorphous alloy material to the casting mold, and induction heating means arranged in the vicinity of the casting mold.
Here, the cavity portion refers to a space portion inside the mold in which the molded product is formed, and detailed specific examples will be described in the following embodiments.
According to the present invention, the molten metal of the amorphous alloy material is supplied to the casting mold by the molten metal supply means, and the casting mold is rotated by the mold rotating means. Therefore, the molten metal is directed toward the cavity by centrifugal force. Move. Here, the molten metal of the amorphous alloy material is heated by the magnetic flux generated from the induction heating means, but the casting mold formed of the insulator is not heated. Accordingly, by operating the induction heating means until the melt of the amorphous alloy material is filled in the cavity portion, the melt can be reliably filled in the entire cavity portion. In addition, after the amorphous alloy material melt is filled in the entire cavity, the induction heating means is stopped, so that the heated melt is rapidly cooled by the temperature difference from the casting mold, and the amorphous degree High amorphous alloy molded body can be obtained. That is, it is possible to achieve both a high cooling performance and a high filling property, and it is possible to obtain a molded body of an amorphous alloy that hardly causes crystallization and has excellent shape accuracy.

In the centrifugal casting apparatus of the present invention, it is preferable that the casting mold is made of a low magnetic permeability material.
In this case, by using a material having a low magnetic permeability for the casting mold, the magnetic flux generated from the induction heating means reliably passes through the casting mold and is guided into the casting mold. Therefore, the melt of the amorphous alloy material supplied into the casting mold can be heated, and the filling property of the melt can be improved. The low magnetic permeability material means a material having a relative magnetic permeability of 2 or less, for example.

In the centrifugal casting apparatus of the present invention, the casting mold is preferably made of a high thermal conductivity material.
In this case, by using a material having high thermal conductivity for the casting mold, the molten metal of the amorphous alloy material can be rapidly cooled after induction heating of the molten metal is completed. Therefore, a molded body of an amorphous alloy having a high non-crystallinity can be obtained. The high thermal conductivity material refers to a material having a thermal conductivity of 5 W / m · k or more, for example.

Further, in the centrifugal casting apparatus of the present invention, the casting mold _{is, SiC, BN, AlN, Si} 3 N 4, Al 2 O is preferably made of at least one ceramic of the _three.
In this case, since the casting mold is made of ceramic, the conductivity is lost, so that it can be reliably prevented from being heated by the magnetic flux emitted from the induction heating means. Moreover, since such ceramics have high thermal conductivity, the molten metal can be rapidly cooled after induction heating of the molten amorphous alloy material is completed. Therefore, a molded body of an amorphous alloy having a high non-crystallinity can be obtained.

Further, in the centrifugal casting apparatus of the present invention, the induction heating means is constituted by a coil, and the moving part that moves the coil or the casting mold and changes the position of the coil with respect to the cavity part in the casting mold. It is preferable to provide.
In this case, the casting mold can be moved so that the cavity portion of the casting mold is located at the place where the magnetic flux density of the magnetic flux generated from the coil is the highest. Therefore, the heating efficiency of the molten metal of the amorphous alloy material is increased, and the molten metal can be prevented from solidifying during induction heating.

In the centrifugal casting apparatus of the present invention, it is preferable that the induction heating means is composed of a plurality of coils having different shapes.
In this case, a plurality of coils can be arranged corresponding to the position and shape of the cavity portion of each casting mold prepared for each product. Therefore, it is possible to select and set a coil to be used for each casting mold so that the cavity portion of the casting mold is located at a location where the magnetic flux density of the magnetic flux generated from the coil is the highest. Therefore, the heating efficiency of the molten metal of the amorphous alloy material is increased, and the molten metal can be prevented from solidifying during induction heating.

Further, in the centrifugal casting apparatus of the present invention, the induction heating means is constituted by a coil surrounding an outer periphery of a casting mold provided in the mold rotating means, and the diameter of the coil is formed so as to increase downward. It is preferable that
In this case, an eddy current is generated in the molten amorphous alloy material supplied into the casting mold by the magnetic field generated from the coil. At this time, since the diameter of the coil increases as it goes vertically downward, the magnetic field due to the eddy current acts in a direction opposite to the magnetic field generated from the coil. That is, a force is received in a direction (a direction away from the coil) in which the molten metal moves in a diagonally downward direction from the coil toward the rotation center. Therefore, since the molten metal receives a force to move downward in the vertical direction, the molten metal can be prevented from scattering out of the casting mold, and the filling property of the molten metal can be improved and the loss of raw materials can be reduced. it can.

The centrifugal casting apparatus according to the present invention further includes a filling confirmation unit capable of confirming that the molten metal is filled in the cavity portion, and stops the output of the induction heating unit after the filling is confirmed. It is preferable that a control unit for controlling is provided.
In this case, since the timing at which the molten metal is filled in the cavity portion can be surely grasped by the filling confirmation means, the induction heating means is then stopped, thereby suppressing the temperature of the molten metal from rising excessively. it can. Therefore, the molten metal can be cooled in a short time, crystallization hardly occurs, and an amorphous alloy molded body having excellent shape accuracy can be obtained.

In the centrifugal casting apparatus of the present invention, it is preferable that the filling confirmation means is an optical detection means for detecting filling of the molten metal through a window provided connected to the cavity portion.
In this case, the state of the molten metal filled in the cavity portion can be reliably grasped by using the optical detection means that is not affected by the strong electromagnetic field generated from the induction heating means. By using such a detection means, it is possible to suppress the temperature of the molten metal from rising excessively. Therefore, the molten metal can be cooled in a short time, crystallization hardly occurs, and an amorphous alloy molded body having excellent shape accuracy can be obtained.

The method for centrifugal casting of an amorphous metal according to the present invention also includes a mold rotating step for rotating a casting mold having a cavity portion therein and an insulator, and a molten amorphous alloy material is supplied to the casting mold. It is characterized by comprising a molten metal supply step and an induction heating step of induction heating the molten metal introduced into the casting mold.
According to the present invention, the melt of the amorphous alloy material is supplied to the casting mold by the melt supplying process, and the casting mold is rotated by the mold rotating process. Therefore, the molten metal is directed toward the cavity by the centrifugal force. Move. Here, the molten metal of the amorphous alloy material is heated by the magnetic flux generated in the induction heating process, but the casting mold formed of the insulator is not heated. Therefore, by performing the induction heating process until the melt of the amorphous alloy material is filled in the cavity portion, the melt can be reliably filled in the entire cavity portion. In addition, after the melt of amorphous alloy material is filled in the entire cavity, the induction heating process is terminated, so that the heated melt is rapidly cooled by the temperature difference from the casting mold, and the amorphous degree High amorphous alloy molded body can be obtained. That is, it is possible to achieve both a high cooling performance and a high filling property, and it is possible to obtain a molded body of an amorphous alloy that hardly causes crystallization and has excellent shape accuracy.

In the method for centrifugally casting an amorphous metal according to the present invention, the casting mold is preferably made of a low magnetic permeability material.
In this case, by using a material having a low magnetic permeability for the casting mold, the magnetic flux generated in the induction heating process is surely passed through the casting mold and guided into the casting mold. Therefore, the melt of the amorphous alloy material supplied into the casting mold can be heated, and the filling property of the melt can be improved.

In the method for centrifugal casting of amorphous metal according to the present invention, the casting mold is preferably made of a high thermal conductivity material.
In this case, by using a material having high thermal conductivity for the casting mold, the molten metal of the amorphous alloy material can be rapidly cooled after the molten metal induction heating step is completed. Therefore, a molded body of an amorphous alloy having a high non-crystallinity can be obtained.

In the amorphous metal centrifugal casting method of the present invention, it is preferable that the casting mold is made of at least one ceramic of SiC, BN, AlN, Si ₃ N ₄ , and Al ₂ O ₃ .
In this case, since the casting mold is made of ceramics, the conductivity is lost, so that it can be reliably prevented from being heated by the magnetic flux generated in the induction heating process. Moreover, since such ceramics have high thermal conductivity, the molten metal can be rapidly cooled after the induction heating process of the molten amorphous alloy material is completed. Therefore, a molded body of an amorphous alloy having a high non-crystallinity can be obtained.

Further, the amorphous metal centrifugal casting method of the present invention further includes a filling confirmation step for confirming that the molten metal is filled in the cavity portion after the molten metal supply step, and after the filling is confirmed, It is preferable to control so that the said induction heating process is complete | finished.
In this case, since the timing at which the molten metal is filled in the cavity portion can be reliably grasped in the filling confirmation process, it is possible to suppress the temperature of the molten metal from rising excessively by ending the induction heating process thereafter. it can. Therefore, the molten metal can be cooled in a short time, crystallization hardly occurs, and an amorphous alloy molded body having excellent shape accuracy can be obtained.

In the method for centrifugal casting of amorphous metal according to the present invention, it is preferable that the filling confirmation step optically confirms the filling of the molten metal through a window connected to the cavity portion.
In this case, the state of filling the molten metal can be reliably grasped by checking the state of filling of the molten metal in the cavity by an optical method that is not affected by the strong electromagnetic field generated in the induction heating process. By using such a method, it is possible to suppress the temperature of the molten metal from rising excessively. Therefore, the molten metal can be cooled in a short time, crystallization hardly occurs, and an amorphous alloy molded body having excellent shape accuracy can be obtained.

  According to the centrifugal casting apparatus of the present invention, the melt of the amorphous alloy material is supplied to the casting mold by the molten metal supply means, and the casting mold is rotated by the mold rotating means. Move toward the cavity. Here, the molten metal of the amorphous alloy material is heated by the magnetic flux generated from the induction heating means, but the casting mold formed of the insulator is not heated. Accordingly, by operating the induction heating means until the melt of the amorphous alloy material is filled in the cavity portion, the melt can be reliably filled in the entire cavity portion. Also, after the melt of the amorphous alloy material is filled in the entire cavity, the induction heating means is stopped, so that the heated melt is rapidly cooled by the temperature difference from the casting mold, and the amorphous degree High amorphous alloy molded body can be obtained. That is, it is possible to achieve both a high cooling performance and a high filling property, and it is possible to obtain a molded body of an amorphous alloy that hardly causes crystallization and has excellent shape accuracy.

(First embodiment)
Next, a first embodiment of the centrifugal casting apparatus of the present invention will be described with reference to FIGS. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

  FIG. 1 shows a cross-sectional view of a cylindrical centrifugal casting apparatus 10. A casing 11 that functions as a vacuum chamber, and a melting heater 13 (melt supply means) that is disposed in the casing 11 and melts the amorphous alloy material to generate a molten metal and supplies the molten metal to the casting mold 15. And a cavity portion (in this embodiment, the cavity portion 27 (see FIG. 3, later) that accepts the molten metal supplied from the melting heater 13 and can produce a molded body of an amorphous alloy in the cavity portion 17 formed inside. The casting mold 15 provided with the above)), a rotating shaft portion 19 (mold rotating means) configured to be able to rotate the casting mold 15 at a predetermined rotational speed, and a predetermined length along the outer peripheral surface of the casting mold 15 And an induction heating coil 21 (induction heating means) arranged at a distance from each other.

  As shown in FIGS. 2 and 3, the casting mold 15 is made of a non-conductive material having a low relative permeability, for example, AlN (aluminum nitride). Here, the case where the cylindrical molded body 23 as shown in FIG. The casting mold 15 includes a mold holder 31 formed in a circular shape in plan view, and a connection part 32 provided on the bottom surface 31 a of the mold holder 31 and connected to the rotary shaft part 19. In addition, the type | mold holder 31 is comprised so that it can divide into up and down (it can be divided | segmented with the broken line B of FIG. 3).

Here, the material of the casting mold 15 will be described in detail. The casting mold 15 is desirably an insulator and has a relative permeability of 2 or less so as not to be affected by the induction heating coil 21.
Since the casting mold 15 is formed of an insulator, it is not heated by the magnetic flux generated from the induction heating coil 21. Therefore, since the molten metal can be rapidly cooled after the induction heating of the molten metal is completed, crystallization of the amorphous alloy can be prevented. On the other hand, when the casting mold 15 is not an insulator, since the mold itself is heated, the cooling rate of the molten metal becomes slow, and the amorphous alloy is crystallized.
Further, when the relative permeability of the casting mold 15 is 2 or less, the magnetic flux generated from the induction heating coil 21 is surely passed through the casting mold 15 and guided into the casting mold 15. Therefore, the melt of the amorphous alloy material supplied into the casting mold 15 can be heated, and the filling property of the melt can be improved. On the other hand, when the relative permeability of the casting mold 15 is larger than 2, the magnetic flux is not guided into the casting mold 15, so that the molten metal is not heated and the filling property is not improved.
Furthermore, it is desirable that the material of the casting mold 15 has a thermal conductivity of 5 W / m · k or more. When the thermal conductivity of the casting mold 15 is as high as 5 W / m · k or higher, the molten amorphous alloy material can be rapidly cooled after induction heating of the molten metal is completed. Therefore, a molded body 23 of an amorphous alloy having a high degree of non-crystallinity can be obtained. On the other hand, when the thermal conductivity of the casting mold 15 is less than 5 W / m · k, after the induction heating of the molten metal is stopped, the cooling rate of the molten metal is slow and the amorphous alloy is crystallized.
As the material of the casting mold 15 adapted to the above-mentioned conditions, as shown in Table 1 below, SiC, BN, AlN, Si ₃ N ₄ , Al ₂ O _{3 and the} like can be considered.

  In addition, when a material having low thermal conductivity such as Macerite (registered trademark) was adopted for the casting mold 15, the filling property was good, but the cooling rate was insufficient and crystallization was observed in the cast product. In addition, when a conductive material is used for the casting mold 15, the casting mold itself generates heat, and the molded product does not become amorphous. Furthermore, when a material having a high relative magnetic permeability was adopted for the casting mold 15, the molten metal was not heated at all, so that the molten metal was quickly solidified and could not be filled sufficiently.

  Further, a melt introduction port 33 into which a melt of an amorphous alloy material is introduced is formed on the upper surface 31 b of the mold holder 31. The molten metal inlet 33 is formed in a substantially circular shape in the central portion of the mold holder 31 in a plan view (a position corresponding to the rotation center of the rotary shaft 19). A hole 34 is formed vertically downward from the molten metal inlet 33, a substantially tunnel-shaped runner portion 36 is formed radially outward from the bottom surface 35 of the hole 34, and a cavity portion is provided at the tip of the runner portion 36. 27 is formed.

  As shown in FIGS. 3 and 5, in the present embodiment, in the cavity portion 17, an outer mold 25 disposed so as to contact the outer peripheral surface 17 a of the cavity portion 17, and a middle portion disposed in the outer mold 25. And a child 26. Thereby, a complicated molded body 23 as shown in FIG. 4 is manufactured. Instead of providing the outer mold 25 and the core 26, the shape of the cavity portion 17 may be processed in accordance with the shape of the molded body to be manufactured to constitute the cavity portion. When the outer mold 25 and the core 26 are combined, a cavity portion 27 corresponding to the shape of the molded body 23 is formed. The outer mold 25 is configured so as to be divided into two in the vertical direction, like the mold holder 31. The outer mold 25 and the core 26 are detachable from the mold holder 31, and a molded body having a different shape is manufactured by arranging the outer mold and the core in which a cavity portion having a different shape is formed. be able to. Since the molten metal is cooled by being absorbed by the casting mold 15, the thickness of the wall of the casting mold 15 in the region where the molten metal is in contact with the thickness of the cavity portion 27 (that is, the thickness of the molded body 23). It is useful to increase the heat capacity by sufficiently increasing the thickness, for example, a thickness of 10 times or more is suitable. The outer mold 25 and the core 26 are also part of the casting mold 15, and it is appropriate to use the same material.

  The induction heating coils 21 are spaced apart from each other along the outer peripheral surface 31 c of the mold holder 31 of the casting mold 15. The induction heating coil 21 has a length (height) in the axial direction so that the outer peripheral surface 31c can be covered almost entirely. Moreover, the coil holding member 28 (moving part) which can adjust the position of the vertical direction of the induction heating coil 21 is provided. The induction heating coil 21 may be supported so as to be suspended from the upper surface of the housing 11 or may be supported from the side surface of the housing 11. That is, it is only necessary that the induction heating coil 21 can be moved up and down along the axial direction by the coil holding member 28.

  For example, as shown in FIG. 6, both ends of the coil wire constituting the induction heating coil 21 are supported and fixed to the upper surface of the housing 11, and a bent portion 41 is formed in the middle of the coil wire, thereby the coil holding member 28. When the induction heating coil 21 is moved up and down, it can be moved smoothly.

A method for manufacturing the molded body 23 using the centrifugal casting apparatus 10 described above will be described.
First, an amorphous alloy material is disposed at a predetermined position of the melting heater 13, and the inside of the housing 11 is brought into a vacuum state or an inert gas environment.

  Next, the temperature of the melting heater 13 is raised, and the amorphous alloy material is melted to generate a molten metal of the amorphous alloy material. Further, the rotating shaft portion 19 is rotated at a predetermined rotational speed, and a high frequency current is supplied to the induction heating coil 21 to generate a magnetic field from the induction heating coil 21.

  The molten amorphous alloy material generated by the melting heater 13 is dropped and supplied to the molten metal inlet 33 of the rotating casting mold 15. The molten metal supplied to the molten metal inlet 33 is dropped onto the bottom surface 35 of the hole 34 and is guided from the runner 36 to the cavity 27 by the centrifugal force of the casting mold 15.

The introduced molten metal flows into a cavity portion 27 formed between the outer mold 25 and the core 26.
At this time, since the melt of the amorphous alloy material is heated by the magnetic field (magnetic flux) generated from the induction heating coil 21, it is reliably guided to the cavity 27 without being cooled and solidified by the heat of the casting mold 15. It is burned.

After the molten metal is completely filled in the cavity 27, the flow of the high-frequency current to the induction heating coil 21 is stopped by an instruction from a control unit (not shown).
At this time, only the molten metal is heated by the magnetic flux generated from the induction heating coil 21, and the casting mold 15 is not heated. Therefore, when the supply of the high-frequency current to the induction heating coil 21 is stopped, the molten metal immediately begins to be cooled, and the molten metal is rapidly solidified.

  Then, the mold holder 31 of the casting mold 15 is divided into two parts, the outer mold 25 and the core 26 are taken out from the cavity portion 17, the outer mold 25 is divided into two parts and the molded body 23 is taken out, so that a desired cast product ( A shaped body 23) can be obtained.

  According to the present embodiment, the centrifugal casting apparatus 10 for casting the amorphous alloy material has the configuration including the induction heating coil 21 along the outer peripheral surface of the casting mold 15, and therefore the magnetic flux generated from the induction heating coil 21. As a result, the melt of the amorphous alloy material is heated, but the casting mold 15 formed of an insulator is not heated. Therefore, by operating the induction heating coil 21 until the melt of the amorphous alloy material is filled in the cavity portion 27, it is possible to suppress cooling and solidification until the melt is filled in the cavity portion 27, The molten metal can be reliably filled in the entire cavity portion 27. Further, after the melt of the amorphous alloy material is filled in the entire cavity portion 27, by stopping the supply of the high-frequency current to the induction heating coil 21, the heated melt is caused by the temperature difference from the casting mold 15. The amorphous alloy compact 23 having a high degree of amorphousness can be obtained by being rapidly cooled. That is, it is possible to obtain both the high cooling performance and the high filling property, the crystallization hardly occurs, and the amorphous alloy molded body 23 having excellent shape accuracy.

  Further, since the material having the relative permeability of 2 or less is adopted as the material of the casting mold 15, the magnetic flux generated from the induction heating coil 21 is surely passed through the casting mold 15 and guided into the casting mold 15. Therefore, the melt of the amorphous alloy material supplied into the casting mold 15 can be heated, and the filling property of the melt can be improved.

  Further, since the material of the casting mold 15 has a thermal conductivity of 5 W / m · k or more, the molten amorphous alloy material can be rapidly cooled after induction heating of the molten metal is completed. Therefore, a molded body 23 of an amorphous alloy having a high degree of non-crystallinity can be obtained.

  In addition, since ceramic AlN is used for the casting mold 15, there is no electrical conductivity, and it can be reliably prevented from being heated by the magnetic flux emitted from the induction heating coil 21. Moreover, since such ceramics have high thermal conductivity, the molten metal can be rapidly cooled after induction heating of the molten amorphous alloy material is completed. Accordingly, it is possible to obtain an amorphous alloy compact 23 having a high degree of non-crystallinity.

  Furthermore, since the induction heating coil 21 is held by the coil holding member 28 and the induction heating coil 21 is configured to be movable in the vertical vertical direction, a casting mold is formed at a location where the magnetic flux density of the magnetic flux generated from the induction heating coil 21 is highest. The 15 cavity portions 27 can be moved. Therefore, the heating efficiency of the molten metal of the amorphous alloy material is increased, and the molten metal can be prevented from solidifying during induction heating.

In the conventional centrifugal casting apparatus in which the molten metal is filled in the casting mold 15 using centrifugal force, if the dropping temperature of the molten metal is too low, the molten metal is cooled and solidified quickly in the cavity portion 27 due to heat conduction with the casting mold 15. Risk increases. However, if the dropping temperature of the molten metal is increased in order to avoid such cooling and solidification, the temperature of the casting mold 15 is increased by heat exchange with the casting mold 15 after being filled in the cavity portion 27, so that the cooling capacity Decreases and the risk of crystallization increases. Further, when the melting temperature is high, the load on the apparatus is large, and the material such as the casting mold 15 in contact with the molten metal can withstand the influence of the high temperature itself and the thermal shock, thermal crack, and seizure generated thereby. Limited. Furthermore, when the temperature is extremely increased beyond the melting point, a highly volatile alloy composition starts to volatilize, and there is a problem that the alloy composition collapses or crystallizes. According to the centrifugal casting apparatus 10 of the present embodiment, the filling property to the cavity 27 can be improved while maintaining the cooling capacity of the casting mold 15 without extremely increasing the dropping temperature of the molten metal.
As described above, the present embodiment has a special effect that it is possible to solve a problem that has been difficult with the prior art.

(Second embodiment)
Next, a second embodiment of the centrifugal casting apparatus of the present invention will be described based on FIGS. Note that this embodiment is different from the first embodiment only in the configuration of the induction heating coil, and other configurations are substantially the same as those in the first embodiment. Is omitted. In the present embodiment, the outer mold 25 and the core 26 are not provided in the cavity portion 17, and the shape of the cavity portion 17 is processed according to the shape of the molded body to be manufactured. The cavity portion 17 is configured (the same applies to the following embodiments).

  As shown in FIG. 7, the induction heating coil 121 is disposed so as to cover substantially the entire outer peripheral surface 31 c of the mold holder 31 of the casting mold 15. In addition, the induction heating coil 121 is configured such that the coil diameter increases as it goes vertically downward (downward in the axial direction). The induction heating coil 121 can be moved up and down along the axial direction by the coil holding member 28.

  With this configuration, as shown in FIG. 8, when a high-frequency current is passed through the induction heating coil 121 when the molten alloy G is dropped onto the casting mold 15, the magnetic field generated in the induction heating coil 121 causes Eddy current I is generated in the molten metal G supplied into the casting mold 15, and the molten metal itself generates heat due to the electric resistance of the molten metal.

  At this time, since the magnetic field due to the eddy current I generated in the molten metal G is generated so as to repel the magnetic field generated in the induction heating coil 121, the induction heating coil 121 and the molten metal are moved away from the line of the induction heating coils 121. In the meantime, repulsive force in the direction of arrow A1 is generated.

  Moreover, since the centrifugal force (arrow A2) by the casting mold 15 rotating also arises in the molten metal G, the external force of the arrow A3 direction is applied to the molten metal G as a result.

  Since the external force A3 is directed obliquely downward, the molten metal that normally overflows from the molten metal inlet 33 of the casting mold 15 due to the centrifugal force A2 caused by the rotation of the casting mold 15 is overflowed by the downward external force A3. Can be suppressed, and the filling property to the cavity portion 17 can be further enhanced. As a result, it is possible to reduce the loss of raw materials due to the molten metal splashing out of the casting mold 15 and the maintenance frequency of the casing 11 that houses the casting mold 15.

(Third embodiment)
Next, a third embodiment of the centrifugal casting apparatus of the present invention will be described based on FIG. Note that this embodiment is different from the first embodiment only in the configuration of the induction heating coil, and other configurations are substantially the same as those in the first embodiment. Is omitted.

  As shown in FIG. 9, the induction heating coil 221 is disposed so as to cover substantially the entire outer peripheral surface 31 c of the mold holder 31 of the casting mold 15. The induction heating coil 221 has a plurality of coils 221a to 221c having different coil diameters. The induction heating coil 221 is configured to move up and down along the axial direction by the coil holding member 28.

If comprised in this way, according to the magnitude | size (diameter) of the casting mold 15, the optimal thing can be selected in the coils 221a-221c. Therefore, it can set for every casting mold 15 so that the cavity part 17 of the casting mold 15 may be located in the location where the magnetic flux density of the magnetic flux generated from the induction heating coil 221 is the highest. Therefore, the heating efficiency of the molten metal of the amorphous alloy material is increased, and the molten metal can be prevented from solidifying during induction heating.
In the present embodiment, the induction heating coil 221 is configured to be moved and selected. However, the coil 221a to 221c to be used by moving the rotary shaft portion 19 up and down is selected, or the connection portion of the mold holder 31 is used. Even if the shape of 32 is changed according to the coil to be used, the same effect is obtained.

(Fourth embodiment)
Next, a fourth embodiment of the centrifugal casting apparatus of the present invention will be described with reference to FIG. Note that this embodiment is different from the first embodiment only in the configuration of the casting mold, and the other configurations are substantially the same as those in the first embodiment. Omitted.

  As shown in FIG. 10, the casting mold 115 includes a mold holder 131 formed in a circular shape in plan view, and a connection portion 132 provided on the bottom surface of the mold holder 131 and connected to the rotary shaft portion 19. In addition, the type | mold holder 131 is comprised so that it can divide into two in the up-down direction.

  Here, a filling sensor 150 (filling confirmation means) is provided on the outer peripheral surface 131 a side of the cavity portion 17 of the mold holder 131. The filling sensor 150 has, for example, two terminals (not shown) at the tip facing the cavity portion 17. When the molten metal of the amorphous alloy material comes into contact with the terminals, the filling sensor 150 is short-circuited and has an electric resistance. It has come to decline significantly. That is, by detecting a change in the electric resistance value of the filling sensor 150, it is possible to detect whether or not the molten metal is filled in the cavity portion 17.

  According to this embodiment, since the filling sensor 150 is provided in the cavity portion 17 of the casting mold 115, it is possible to more reliably grasp the timing when the cavity portion 17 is filled with the molten metal. Therefore, immediately after the cavity portion 17 is filled with the molten metal, by stopping the supply of the high-frequency current to the induction heating coil 21, the temperature of the molten metal is excessively increased or the temperature of the casting mold 115 is increased. Can be suppressed. Therefore, the molten metal can be cooled in a short time, crystallization hardly occurs, and an amorphous alloy molded body having excellent shape accuracy can be obtained.

(Fifth embodiment)
Next, a fifth embodiment of the centrifugal casting apparatus of the present invention will be described based on FIG. Note that this embodiment is different from the first embodiment only in the configuration of the casting mold, and the other configurations are substantially the same as those in the first embodiment. Omitted.

  As shown in FIG. 11, the casting mold 215 includes a mold holder 231 formed in a circular shape in plan view, and a connection portion 232 provided on the bottom surface of the mold holder 231 and connected to the rotary shaft portion 19. In addition, the type | mold holder 231 is comprised so that it can divide into two in the up-down direction.

  Here, an optical window 250 is provided on the upper surface 231a corresponding to the position where the cavity portion 17 of the mold holder 231 is formed. A laser light source 251 capable of emitting laser light toward the optical window 250 is provided vertically above the position corresponding to the position where the optical window 250 is disposed, and a lens 252 capable of condensing the laser light emitted from the laser light source 251. An optical detection device 255 including a beam splitter 253 that converts the direction of reflected light from the optical window 250 direction toward the light receiving element 254 and a light receiving element 254 that receives light from the beam splitter 253. It is arranged inside.

  Laser light emitted from the laser light source 251 and transmitted through the optical window 250 is applied to the cavity portion 17. In the state where the melt is not filled in the cavity portion 17, the laser light is scattered in the cavity portion 17, so that the amount of light that can be detected by the light receiving element 254 is small. When the melt of the amorphous alloy material is filled in the cavity portion 17 and is filled to the position where it comes into contact with the optical window 250, the laser light is reflected by the melt, and the reflected light is further partially reflected by the beam splitter 253. Then, it reaches the light receiving element 254. In the light receiving element 254, the received laser beam is detected more strongly as an electric signal. That is, it is possible to detect whether or not the molten metal is filled in the cavity portion 17 based on a change in the electrical signal detected by the optical detection device 255.

  According to the present embodiment, the optical window 250 is provided in the cavity portion 17 of the casting mold 215, and the optical detection device 255 is disposed in the housing 11 together with the optical window 250. That is, by using an optical detection means (optical detection device 255) that is not affected by the strong electromagnetic field generated from the induction heating coil 21, the state of the molten metal filled in the cavity portion 17 can be reliably grasped. it can. Further, by using the optical detection device 255, it is possible to suppress the temperature rise of the molten metal or the mold in contact with the molten metal. Therefore, the molten metal can be cooled in a short time, crystallization hardly occurs, and an amorphous alloy molded body having excellent shape accuracy can be obtained.

  Next, the result of having measured the filling degree and crystallinity degree of the melt of an amorphous alloy using the centrifugal casting apparatus 10 mentioned above is demonstrated.

The amorphous alloy _material, with metallic glass material _{Zr 55 Cu 30 Al 10 Ni 5} . In addition, although the rotation speed of the casting mold 15 changes with kinds of the amorphous alloy and metal used as the material to cast, and the shape of the casting mold 15, it is preferable to set it as the range of 1000-5000 rpm normally. In this embodiment, it was 3000 rpm.
The evaluation method and evaluation criteria are as follows.
<Amorphous degree> The degree of crystallinity is determined by using a fluorescent X-ray apparatus (XRD) and setting several places on the surface of the molded body 23 to determine whether or not there is a peak indicating the crystalline state of the place. evaluated. Regarding the non-crystallinity, it was considered that crystallization was not progressing when no peak was present in the XRD measurement result, and it was judged as ◯ (passed), and when there was no peak, it was marked as x (failed).
<Filling property> The filling rate of the molten metal into the cavity portion 17 is obtained by comparing the ideal weight obtained from the volume of the cavity portion 17 and the specific gravity of the material of the molten metal with the actual weight of the molded body 23. is there. When this filling rate was 95% or more, it was set as “◯” (passed), and when it was less than 95%, it was set as “x” (failed).
<Comprehensive judgment> ○: When the degree of amorphousness and fillability are both ○
X: When at least one of amorphousness and filling property is x

  As shown in Table 2, in Examples 1 to 5 according to the first embodiment to the fifth embodiment, both the filling rate and the degree of crystallinity have passed, and the metallic glass has excellent shape accuracy. It was confirmed that the molded body 23 can be manufactured. On the other hand, in the comparative example, when the casting mold 15 formed of copper was used and the heating process by the induction heating coil 21 was not performed, it was confirmed that the filling rate was not satisfied. Therefore, it was confirmed that the filling rate into the cavity portion 17 can be increased by heating the melt of the amorphous alloy (metal glass) material by the induction heating coil 21.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific materials, configurations, and the like given in the embodiment are merely examples, and can be changed as appropriate.
For example, in this embodiment, the induction heating coil is configured to be moved vertically in the vertical direction by the coil holding member. However, the induction heating coil is fixed and the casting mold (and the rotating shaft portion) can be moved up and down. May be.

It is a schematic block diagram of the centrifugal casting apparatus in 1st embodiment of this invention. It is a top view of the casting mold in the first embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. It is a perspective view of the molded object in embodiment of this invention. It is a perspective view which shows the structural member of the cavity part in embodiment of this invention. It is a schematic block diagram of the induction heating coil in embodiment of this invention. It is a schematic block diagram of the centrifugal casting apparatus in 2nd embodiment of this invention. It is explanatory drawing explaining the force which acts on the molten metal of the amorphous alloy in 2nd embodiment of this invention. It is a schematic block diagram of the centrifugal casting apparatus in 3rd embodiment of this invention. It is a schematic block diagram of the casting die in 4th embodiment of this invention. It is a schematic block diagram of the centrifugal casting apparatus in 5th embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Centrifugal casting apparatus 13 ... Melting heater (molten supply means) 15, 115, 215 ... Casting die 17, 27 ... Cavity part 19 ... Rotating shaft part (mold | rotation means) 21, 121, 221 ... Induction heating coil 28 ... Coil Holding member (moving part) 150... Filling sensor (filling confirmation means) 250... Optical window (window) 255... Optical detection device (optical detection means) G.

Claims (15)

In a centrifugal casting apparatus for casting an amorphous alloy,
A casting mold made of an insulator having a cavity inside;
Mold rotating means for rotating the casting mold;
A molten metal supply means for supplying the molten metal of the amorphous alloy material to the casting mold;
And an induction heating means disposed in the vicinity of the casting mold.   The centrifugal casting apparatus according to claim 1, wherein the casting mold is made of a low magnetic permeability material.   The centrifugal casting apparatus according to claim 1 or 2, wherein the casting mold is made of a high thermal conductivity material. The centrifugal casting apparatus according to claim 1, wherein the casting mold is made of at least one ceramic among SiC, BN, AlN, Si ₃ N ₄ , and Al ₂ O ₃ . The induction heating means comprises a coil;
The moving part which moves this coil or the said casting mold, and changes the position with respect to the cavity part in the said casting mold is provided. Centrifugal casting equipment.   The centrifugal casting apparatus according to claim 1, wherein the induction heating unit includes a plurality of coils having different shapes. The induction heating means is composed of a coil surrounding the outer periphery of a casting mold provided in the mold rotating means,
The centrifugal casting apparatus according to any one of claims 1 to 6, wherein the diameter of the coil is formed so as to increase in the vertical direction. A filling confirmation means capable of confirming that the molten metal is filled in the cavity portion;
The centrifugal casting apparatus according to any one of claims 1 to 7, further comprising a control unit that controls to stop the output of the induction heating unit after the filling is confirmed.   The centrifugal casting apparatus according to claim 8, wherein the filling confirmation unit is an optical detection unit that detects filling of the molten metal through a window connected to the cavity portion. A method for centrifugal casting of an amorphous alloy for casting an amorphous alloy,
A mold rotating step of rotating a casting mold made of an insulator having a cavity inside;
A melt supply step for supplying a melt of an amorphous alloy material to the casting mold;
And an induction heating step of induction heating the molten metal introduced into the casting mold.   The method for centrifugal casting of an amorphous alloy according to claim 10, wherein the casting mold is made of a low magnetic permeability material.   The method for centrifugal casting of an amorphous alloy according to claim 10 or 11, wherein the casting mold is made of a high thermal conductivity material. The casting mold is, SiC, _{BN, AlN,} the Si 3 N _4, Al 2 _O amorphous alloy according to any one of claims 10 to 12, characterized in that it consists of at least one ceramic of the _three centrifugation Casting method. After the molten metal supply step, further comprising a filling confirmation step for confirming that the molten metal is filled in the cavity portion,
The method for centrifugal casting of an amorphous alloy according to any one of claims 10 to 13, wherein the induction heating step is controlled after filling is confirmed.   The method for centrifugal casting of an amorphous alloy according to claim 14, wherein the filling confirmation step optically confirms the filling of the molten metal through a window provided in connection with the cavity portion.

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