JP2015134377A - Melting continuous casting apparatus for high purity ingot and melting continuous casting method for high purity ingot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melting continuous casting apparatus for a high purity ingot capable of producing the high purity ingot which has uniform composition and shape, and can produce a hollow billet having surface roughness of which is preferably suppressed.SOLUTION: A melting continuous casting apparatus for a high purity ingot is a facility for producing an ingot of metal or of an inorganic compound. In the melting continuous casting apparatus, a continuous casting part is connected to a lower part of a part 1 where raw material is heated and melted, and a metal melting/holding part 14 having a function of heating/melting the raw material and a function of holding melted molten metal and a casting outer peripheral part 7 are integrated into an integral structure.

Description

  The present invention relates to a high-purity ingot melting continuous casting apparatus and a high-purity ingot melting continuous casting method.

  In recent years, the demand for photovoltaic power generation has increased rapidly, and the development of constituent materials for photovoltaic power generation has been actively promoted. A solar cell used for photovoltaic power generation generally has a structure in which a back electrode layer, a light absorption layer, a resistance buffer layer, and a transparent conductive layer are formed in this order on a substrate. It is preferable that the light absorption layer of the solar cell has a large light absorption capability, and various materials have been developed from such a viewpoint.

  As a material for a light absorption layer of a solar cell, a CIS alloy that is a quinary alloy of Cu (Group I), In / Ga (Group III), and Se / S (Group VI) is known. CIS alloys cover a wide spectrum range of sunlight and have a high light absorption capability. The light absorption layer is formed on a base material such as a glass substrate by sputtering using a CIS alloy as a target material.

  The target material is usually formed in a plate shape for reasons such as ease of production. However, when a plate-like target material is used, there is a problem that the surface of the target material is used in a donut shape and the use efficiency of the target material is low.

  On the other hand, a sputtering technique using a rotary target has been put into practical use in which sputtering is performed while rotating the target by using a hollow billet as the target material, thereby improving the use efficiency of the target material.

  As such a technique, for example, in Patent Document 1, a core is disposed in a hollow part that is open vertically in a hollow or other hollow water-cooled mold having a cross section, and is formed between the water-cooled mold and the core. While the molten metal is continuously supplied into the annular casting path, the cradle is initially lowered so as to seal the lower end of the casting path, and the supplied molten metal is solidified in the casting path. In an apparatus for producing a hollow billet by continuously pulling out an annular ingot while maintaining a solidification start point to be substantially constant, the core (a) temporarily supplies a molten metal to be supplied into the casting path. (B) a core side of a heat receiving part made of a heat receiving material and a heat receiving material integrally formed at an upper part thereof with a molten metal receiving tank for receiving the molten metal from the molten metal receiving tank into the casting path. Including the solidification start point A casting part made of graphite or carbonaceous material for forming a core-side casting surface having a taper-shaped taper having a small diameter on the lower side in an appropriate length range in the vertical direction is fixed. A featured continuous billet casting apparatus is disclosed.

  Patent Document 2 discloses a refractory material in a hot top casting method in which a molten metal receiving tank made of a heat-insulating material refractory for holding a molten metal on a mold is fed from a casting furnace to a mold through a launder. In a method of casting a hollow billet by a continuous casting method with a core made concentrically installed inside a water-cooled mold, the temperature of a coolant flow tube and a temperature detection device for circulating a coolant through the core A method for casting a hollow billet, characterized by providing a detection end and controlling the temperature of the core by adjusting the flow rate or temperature of the coolant in the coolant flow tube in accordance with the temperature detected by the temperature detection device. Is disclosed.

  Further, in Patent Document 3, an asynchronous external mold having a cooling structure on the outside or the outer periphery is installed, and an asynchronous internal mold having a cooling structure on the inside or the inner periphery is formed in the internal space formed by the external mold. The mold is inserted between the inner mold and the outer mold so as to constitute a mold space for allowing molten metal to flow from the hot water nozzle, and the inner mold is directed from the molten metal meniscus toward the casting direction and the outer shape of the inner mold. There is disclosed a continuous casting mold for hollow round slab characterized by continuously reducing the size of the hollow round slab.

Japanese Patent Laid-Open No. 61-134542 Japanese Patent Publication No. 1-31971 JP-A-5-293597

  In the vertical continuous casting as disclosed in the above patent document, the shape of the hollow billet is obtained by pouring the molten metal into the hollow space formed by the outer mold and the inner mold, cooling it, and continuously pulling it out while solidifying. The resulting ingot is produced. Depending on the atmosphere (air), refractory materials, etc., to supply the molten metal to the molten metal receiving tank made of heat-insulating refractory through a launder made of heat-insulating material, or from the hot water nozzle. Contamination of the molten metal occurs. Oxidation of active elements in the molten metal, oxidation of the molten metal with water and associated hydrogen intrusion into the molten metal, generation of pinholes in the ingot due to hydrogen gas, reaction with the refractory member during the transfer of the molten metal, or removal of the refractory material Degradation of purity occurs due to mixing into the molten metal due to. Also, in the vertical continuous casting, if the position where the molten metal begins to solidify and the state of solidification in the mold vary between continuous castings, the configuration of the target material of the produced hollow billet becomes non-uniform, Further, the surface (casting surface) becomes rough, the frictional resistance between the hollow billet, the mold and the core is large, making continuous casting difficult, and various adverse effects on sputtering may occur. In particular, when producing a hollow billet containing copper as a main component, the thermal conductivity of copper is very high, so that it is difficult to control the heat during casting. In addition, when using a Cu—Ga alloy in which gallium is added to copper, the difference in melting point between copper and gallium is large, so it is very difficult to obtain a uniform composition and shape by continuous casting. It was.

  Accordingly, one of the objects of the present invention is to provide a high-purity ingot melting continuous casting apparatus capable of producing a hollow billet having a uniform composition and shape and whose surface roughness is satisfactorily suppressed. To do. Another object of the present invention is to provide a high-purity ingot melting continuous casting method using such a mold.

  As a result of intensive research to solve the above problems, the present inventor has found that a high-purity ingot free from pinhole defects can be produced by connecting a continuous casting portion to the lower portion. It was. Also, to create a hollow billet that has a uniform composition and shape by well controlling the conditions for cooling the casting space of the continuous casting part from the outside and the inside, and the surface roughness of the ingot is well controlled I found out that I can.

  The present invention completed on the basis of the above knowledge is, in one aspect, a facility for producing an ingot of a metal or an inorganic compound, and is a high-purity ingot in which a continuous casting portion is connected to a lower portion of a portion where a raw material is heated and melted. It is a melting continuous casting device.

  In another aspect of the present invention, the molten continuous casting according to the present invention includes a step of cooling the molten metal that has flowed into the casting space from a metal melting / holding portion having a function of retaining the molten metal by melting the raw material by heating and melting. This is a continuous casting method for high-purity ingots using an apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the melt | dissolution continuous casting apparatus of the high purity ingot which can produce the hollow billet which has a uniform composition and shape and the surface roughness was suppressed favorably can be provided.

The cross-sectional schematic diagram of the melt | dissolution continuous casting apparatus of the high purity ingot which concerns on embodiment of this invention is shown. The upper surface schematic diagram of the melt | dissolution continuous casting apparatus of the high purity ingot which concerns on embodiment of this invention is shown. The expansion schematic diagram of the lower left part of the melt | dissolution continuous casting apparatus of the high purity ingot which concerns on embodiment of this invention is shown. The enlarged schematic diagram of the lower left part of the melt | dissolution continuous casting apparatus of the high purity ingot which concerns on other embodiment of this invention is shown. The expansion schematic diagram of the lower part of the melt | dissolution continuous casting apparatus of the high purity ingot which concerns on other embodiment of this invention is shown. The schematic diagram of the core for demonstrating the inclination of the taper of the core which concerns on embodiment of this invention is shown. The cross-sectional schematic diagram of the melt | dissolution continuous casting apparatus of the high purity ingot which concerns on embodiment of this invention is shown.

  Hereinafter, embodiments of the present invention will be described in detail.

(Configuration of high-purity ingot melting continuous casting equipment)
A schematic cross-sectional view of the high-purity ingot melting continuous casting apparatus of the present invention is shown in FIG. FIG. 2 is a schematic top view of a high-purity ingot melting continuous casting apparatus. FIG. 3 is an enlarged schematic diagram of the lower left portion of the high-purity ingot melting continuous casting apparatus.

  The high-purity ingot melting and continuous casting apparatus of the present invention is a crucible 1 having a columnar core 2 and a metal melting / holding portion 14 having a function of melting a metal located above the core 2 and holding the molten metal. With. That is, in the continuous melting casting apparatus, the continuous casting part is connected to the lower part of the part where the raw material is heated and melted.

  The crucible 1 forms a casting space of the hollow billet 9 into which the molten metal (molten metal 8) flows from the metal melting / holding portion 14 having the function of melting the metal and the function of retaining the molten metal with the outer peripheral surface of the core 2. It has a casting outer peripheral portion 7 to be configured, and includes cooling portions 3 and 15 for cooling the casting space by dividing it into a plurality of portions in the depth direction from the outer peripheral side and the inner peripheral side, respectively. As described above, the cooling units 3 and 15 divide the casting space into a plurality of portions in the depth direction from the outer peripheral side and the inner peripheral side, respectively, and cool it, so that the solidified state of the molten metal 8 in the casting space is good in the depth direction. Can be controlled. The metal melting / holding unit 14 having a function of melting a metal and a function of holding a molten metal is provided with an inert gas introducing unit 12 for introducing an inert gas, thereby reducing the oxygen partial pressure in the molten metal 8. ing. As the heating method of the molten metal 8 of the metal melting / holding unit 14 having the function of melting the metal and holding the molten metal, resistance heating, high-frequency induction heating, or the like can be used.

  The cooling part 3 for cooling the casting space from the outer peripheral side is provided on the outer peripheral side of the casting outer peripheral part 7 of the crucible 1. As the cooling part 3 provided on the outer peripheral side of the casting outer peripheral part 7 of the crucible 1, a refrigerant jacket such as a water-cooled copper jacket provided with a plurality of small cooling parts divided in the depth direction can be provided. Each of the plurality of small cooling units may have a structure including a path through which a coolant such as water passes. The temperature control of each small cooling unit can be performed by adjusting the flow rate, flow rate, temperature, and the like of the refrigerant flowing through the refrigerant jacket. With such a configuration, the molten metal 8 can be efficiently cooled by simple means. In addition, since the refrigerant does not directly contact the molten metal 8, there is no risk of a steam explosion even if a hot water leak occurs.

  The cooling section used in the high-purity ingot melting continuous casting apparatus of the present invention is not configured to cool by dividing the casting space into a plurality of portions in the depth direction from the outer peripheral side and the inner peripheral side as described above. May be. For example, as shown in FIG. 4, the cooling unit 3 ′ may not be divided. With such a configuration, the molten metal 8 can be efficiently cooled by simple means. In addition, since the refrigerant does not directly contact the molten metal 8, there is no risk of a steam explosion even if a hot water leak occurs.

  As shown in FIG. 5, each of the cooling units 3, 3 ′ used in the high-purity ingot melting and continuous casting apparatus of the present invention may include a flow path 21 that moves up and down in the depth direction. The flow path 21 is configured so that the refrigerant passes through it. As shown in FIG. 5, the flow path 21 may be configured such that the refrigerant continuously flows in the circumferential direction in the casting space while moving up and down in the depth direction of the cooling units 3 and 3 ′. With such a configuration, the molten metal 8 can be cooled more efficiently by simple means. In addition, since the refrigerant does not directly contact the molten metal 8, there is no risk of a steam explosion even if a hot water leak occurs.

It is preferable that the metal melting / holding portion 14 having a function of melting the metal of the crucible 1 and holding the molten metal and the casting outer peripheral portion 7 are integrally formed. According to such a configuration, manufacturing efficiency is improved. Further, the metal melting / holding portion 14 and the cast outer peripheral portion 7 may be formed of a plurality of constituent pieces and / or a plurality of materials. The metal dissolving / holding portion 14 can be formed of fine ceramics such as alumina (Al ₂ O ₃ ), mullite (3Al ₂ O ₃ .2SiO ₂ ) zirconia (ZrO ₂ ), graphite, etc. Preferably it is formed. Graphite is a material rich in lubricity with respect to metals, particularly copper alloys, and can produce a hollow billet 9 rich in surface quality in which surface roughness is well suppressed. Moreover, since it becomes possible to perform precise temperature control over the entire material when it is formed of graphite, the degree of freedom of temperature control of the entire material is increased. Furthermore, the mixing of impurities into the molten metal 8 is suppressed satisfactorily. The casting outer peripheral portion 7 is plated with chromium or the like on the surface thereof such as iron, iron alloy, copper, copper alloy for reasons such as thermal expansion and contraction characteristics, lubricity (reactivity with graphite), and heat removal. It is preferable to use a material in contact with the molten metal and use graphite in a portion where cooling has progressed after casting.

  The crucible 1 has a molten metal temperature measuring thermocouple 13 for measuring the molten metal temperature at the molten metal supply portion that supplies the molten metal 8 from the metal melting / holding portion 14 having the function of melting the metal and holding the molten metal to the casting space. In a state where it is accommodated in a predetermined protective tube, it passes through the thermocouple protective tube insertion port 4 formed so as to penetrate the upper surface of the core 2 and is provided so as to reach the molten metal supply site. Only one thermocouple 13 may be provided, or a plurality of thermocouples 13 may be provided at equal intervals in the circumferential direction. By providing a plurality, it becomes possible to measure the melt temperature at the melt supply site more accurately.

  A tubular hole portion 17 extending in the depth direction is formed in the casting outer peripheral portion 7 of the crucible 1, and the cast hole outer peripheral thermocouple 10 is provided in the tubular hole portion 17. Only one thermocouple 10 may be provided, or a plurality of thermocouples 10 may be provided at equal intervals in the circumferential direction of the casting outer peripheral portion 7. By providing a plurality, it becomes possible to measure the melt temperature at the melt supply site more accurately. Further, the thermocouple 10 has a plurality of temperature measurement points as a unit in the depth direction. According to such a configuration, the solidification state of the molten metal 8 in the casting space cooled by the refrigerant jacket provided with a plurality of small cooling portions divided in the depth direction can be controlled better in the depth direction. It becomes possible. For this reason, the position at which the molten metal 8 starts to solidify and the solidification state in the mold are controlled without variation during continuous casting, thereby making the composition and shape of the target material of the hollow billet 9 produced uniform. In addition, surface roughness can be satisfactorily suppressed. In particular, when producing a hollow billet 9 containing copper as a main component, the thermal conductivity of copper is very high, and thus it has been difficult to control the heat during casting. In addition, when using a Cu—Ga alloy in which gallium is added to copper, the difference in melting point between copper and gallium is large, so it is very difficult to obtain a uniform composition and shape by continuous casting. It was. On the other hand, according to the present invention, since the heat control during casting can be finely performed as described above, even if the Cu-Ga alloy is a material, it has a uniform composition and shape, and the surface is rough. It is possible to produce a hollow billet 9 in which is suppressed satisfactorily.

  Inside the core 2, a cooling unit is provided for cooling the casting space from the inner peripheral side. The cooling part 15 provided inside the core 2 is disposed concentrically and is inserted into the tubular hole part 16 from the refrigerant probe insertion port 6 into the tubular hole part 16 formed so as to extend in the depth direction. It is comprised with the refrigerant | coolant probe using refrigerant | coolants, such as water. A plurality of tubular holes 16 are formed at equal intervals along the circumferential direction, and the material can be cooled uniformly along the circumferential direction. The refrigerant probe is inserted into the tubular hole portion 16. By adjusting the insertion depth at this time, cooling can be performed by dividing into a plurality of portions in the depth direction from the inner peripheral side of the casting space. In addition, since the refrigerant does not directly contact the molten metal 8, there is no risk of a steam explosion even if a hot water leak occurs.

  The core 2 enters the metal melting / holding part 14 having a function of melting the metal of the crucible 1 and holding the molten metal by a predetermined height, and the upper part is enlarged in diameter. A thermocouple protective tube insertion port 4 is formed so as to penetrate the enlarged diameter portion in the vertical direction. Moreover, the edge part of this enlarged diameter part is bent below, and a wall part is formed, and the lower end of the said wall part is contacting the crucible. A molten metal supply port 5 is formed so as to penetrate the wall portion in the lateral direction, and the molten metal 8 in the metal melting / holding unit 14 has a function of melting the metal through the molten metal supply port 5 and holding the molten metal. Flows into the casting space.

  The core 2 is formed in a taper shape with an inclination that the diameter decreases in accordance with the gradient of heat removal as it goes downward. The molten metal 8 in the casting space is cooled and solidified as it progresses downward, and is thermally contracted by the subsequent cooling, and at this time, the diameter is gradually reduced. For this reason, the hollow billet 9 and the core 2 that are produced by forming the core 2 into a taper shape with an inclination that decreases in diameter as the core 2 is moved downward according to the degree of diameter reduction. Suppresses the friction between the two. Therefore, the hollow billet 9 can be continuously and satisfactorily pulled out from the mold 20. Here, FIG. 6 shows a schematic diagram of a core for explaining the inclination of the taper. In FIG. 6, the length of the core is x, and the diameter is y. In this case, the diameter is reduced as it goes from the upper end to the lower end, and if the inclination of the taper is a and the length (diameter) of the upper end is b, the equation y = ax + b holds. When the taper inclination a is more than 0.01, the cast piece is easily pulled out in continuous casting.

  The core 2 can be formed of a metal (iron, copper alloy), graphite, or the like, but is particularly preferably formed of graphite. Graphite is a material rich in lubricity with respect to metals, particularly copper alloys, and can produce a hollow billet 9 rich in surface quality in which surface roughness is well suppressed. Moreover, since it becomes possible to perform precise temperature control over the entire material when it is formed of graphite, the degree of freedom of temperature control of the entire material is increased. Furthermore, the mixing of impurities into the molten metal 8 is suppressed satisfactorily.

  The core 2 is formed with a tubular hole 16 that extends in the depth direction. The tubular hole 16 is provided with a core thermocouple 11. It is preferable to form a plurality of tubular holes 16 at equal intervals along the outer circumferential direction of the core 2. According to such a configuration, the core thermocouple 11 can be provided at one or more locations along the outer circumferential direction of the core 2, and the material can be measured at a plurality of locations along the outer circumferential direction of the core 2. it can. Moreover, it is preferable that the core thermocouple 11 has a plurality of temperature measurement points as a unit in the depth direction. According to such a configuration, the solidification state of the molten metal 8 in the casting space whose cooling state is adjusted in the depth direction by the above-described refrigerant probe can be controlled better in the depth direction. For this reason, the position at which the molten metal 8 starts to solidify and the solidification state in the mold 20 are controlled without variation during continuous casting, thereby making the composition and shape of the target material of the hollow billet 9 produced uniform. Further, surface roughness can be satisfactorily suppressed.

  It is preferable that the temperature measurement points of the casting outer peripheral thermocouple 10 and the core inner thermocouple 11 are formed at the same position in the depth direction of the mold 20. According to such a configuration, it is possible to uniformly control the solidification state of the material in the mold 20 on the outside and the inside in the depth direction, and it has a more uniform composition and shape, and the surface is roughened. A hollow billet 9 that is well suppressed can be produced.

(Configuration of high-purity ingot melting continuous casting apparatus 30)
In FIG. 7, the cross-sectional schematic diagram of the melt | dissolution continuous casting apparatus 30 of the high purity ingot which concerns on embodiment of this invention is shown. The high-purity ingot melting continuous casting apparatus 30 forms a hollow billet 39 by cooling and solidifying a molten metal supplied directly from a metal melting furnace between a mold and a core disposed inside the mold. The continuous casting apparatus continuously casts the hollow billet by pulling out the hollow billet 39 from the mold and the core. The vertical continuous casting apparatus 30 includes a columnar core 32 and a metal melting / holding portion having a function of melting a metal located above the core 32 and a function of holding a molten metal. A continuous casting mold 20 is provided.

  A water-cooled copper jacket 33 that is a cooling unit that cools the casting space from the outer peripheral side is provided on the outer peripheral side of the crucible 31. At this time, since the refrigerant does not directly contact the molten metal 38, there is no risk of a steam explosion even if a hot water leak occurs. The crucible 31 is provided with an inert gas introduction part 42 for introducing an inert gas, and the oxygen partial pressure in the molten metal 38 is reduced.

  A heater 45 is provided on the outer periphery of the crucible 31. A crucible temperature control thermocouple 44 is provided on the wall of the crucible 31. A molten metal temperature measurement thermocouple 43 for measuring the molten metal temperature at the molten metal supply portion that supplies the molten metal 38 from the crucible 31 to the casting space is inserted into the predetermined protective tube so as to penetrate the upper surface of the core 32. It passes through the formed thermocouple protective tube insertion port and is provided so as to reach the molten metal supply site. Inside the core 32, a water-cooling probe 46 that cools the casting space from the inner peripheral side is concentrically arranged, and is inserted into the inside through a refrigerant probe insertion port 36. The vertical continuous casting apparatus 30 of the hollow billet cools and solidifies the molten metal supplied between the mold 20 and the core 32 disposed inside the mold 20 directly from the metal melting furnace, thereby solidifying the hollow billet 39. Then, the hollow billet 39 is continuously drawn by pulling the hollow billet 39 from the mold 20 and the core 32 by the pulling mechanism 47.

(Vertical continuous casting method for hollow billet 9)
Next, the vertical continuous casting method of the hollow billet 9 of the present invention will be described in detail. The casting method is performed using the vertical continuous casting mold 20 of the hollow billet 9 of the present invention.
First, a metal melt 8 of a sputtering target material such as a copper alloy is provided in a metal melting / holding portion 14 having a function of melting the metal of the crucible 1 and a function of holding the molten metal. An inert gas such as nitrogen, argon, or helium from the inert gas introduction unit 12 is continuously supplied to the molten metal 8 of the metal melting / holding unit 14 having a function of melting the metal and holding the molten metal.
Next, the molten metal 8 is caused to flow into the casting space from the metal melting / holding portion 14 having a function of melting the metal and holding the molten metal. In the casting space, a cast piece (metal (pure copper, Cu—Ga alloy) piece) or a graphite piece for continuously drawing the solidified molten metal 8 from the mold 20 is inserted in advance from the bottom surface direction. The molten metal 8 that has flowed into the casting space is divided into a plurality of portions in the depth direction from the outer peripheral side and the inner peripheral side, cooled, and solidified on the previously inserted cast piece. The hollow billet 9 is continuously produced by continuously pulling out the cast piece at a predetermined speed while continuously flowing in and cooling the molten metal 8. The cast piece can be pulled out in a continuous pattern in which the time of advance, stop, retreat, etc. is set as in the conventional case.

Cooling of the outer peripheral side of the casting space is performed by adjusting individually at a depth position by a refrigerant jacket provided on the outer peripheral side of the casting outer peripheral portion 7 of the crucible 1 and having a plurality of small cooling portions. In addition, the materials at the positions divided into a plurality are adjusted in the cooling state while being measured by the thermocouple 10 in the outer periphery of the casting.
Cooling of the inner circumferential side of the casting space is performed by individually adjusting the depth position according to the degree of insertion of the refrigerant probe provided inside the core 2. In particular, the adjustment of the solidification start position is important, and there is a possibility that the surface of the hollow billet 9 is roughened even if it is hardened too early in the casting space, and if it is hardened too late, the molten metal 8 is a vertical mold. There is a risk of leaking under the casting space.
The management of the cooling temperature is basically adjusted so that the material of the casting space is changed from strong to weak as it goes from the upper direction to the lower direction, but the measured values of the thermocouples 10 and 11 are confirmed. However, it is preferable to finely control the temperature in the depth direction so that the temperature is appropriate for each alloy. Thereby, since the solidification start position of the molten metal 8 and the solidification form in the depth direction can be adjusted satisfactorily, a hollow billet 9 having a uniform composition and shape and having a sufficiently suppressed surface roughness is produced. can do.
Further, the cooling on the outer peripheral side of the casting space is performed by the speed of the refrigerant flowing in the flow path 21 that goes up and down in the depth direction inside the cooling part as shown in FIG. 5 provided on the outer peripheral side of the casting outer peripheral part 7 of the crucible 1. You may adjust by.
Further, by forming the temperature measurement points of the thermocouple 10 provided on the outer periphery 7 of the crucible 1 and the thermocouple 11 provided on the core 2 at the same position in the mold depth direction, The solidified state of the inner material can be uniformly controlled in the depth direction between the outside and the inside, and a hollow billet 9 having a more uniform composition and shape and having excellent surface roughness suppressed is produced. be able to.
In addition, a hollow billet for a rotary sputter target made of a Cu—Ga alloy can be produced in this manner.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

Example 1
A high-purity ingot melting continuous casting apparatus having the same configuration as that described in FIGS. In the metal melting / holding portion having the function of melting the metal and holding the molten metal, a molten Cu-29 at% Ga alloy maintained at 960 ° C. was provided, and nitrogen gas was continuously introduced. The crucible and core were each formed of graphite. The casting space was 129 mm in inner diameter, 160 mm in outer diameter, and 200 mm in height. The outer diameter of the upper end of the core was 129 mm, and the outer diameter of the lower end of the core was 123 mm.
Next, the molten metal of the metal melting / holding part, which has the function of melting the metal and holding the molten metal, is poured into the casting space, and the cooling part divided into a plurality at the depth position provided in the crucible and the core, the While adjusting the cooling state of the position, the cast piece was pulled out and the hollow billet was continuously cast. The crucible and core cooling sections are divided into five sections at equal intervals in the depth direction (section A, section B, section C, section D, section E from the top to the bottom), and each cooling section has thermoelectric power. A pair of measurement points was provided. In each of the crucible and core cooling sections, the cooling temperature of section A is 850 ° C., the cooling temperature of section B is 400 ° C., the cooling temperature of section C is 250 ° C., the cooling temperature of section D is 200 ° C., The cooling temperature of section E was 150 ° C.
The drawing pattern of the cast piece was set by appropriately combining drawing, stopping, and retreating at a drawing speed of 70 mm / min.
The hollow billet thus produced had a uniform composition and shape throughout, and the surface roughness was well suppressed.

(Example 2)
As shown in FIGS. 4 and 5, the outer peripheral cooling section is not divided, and the cooling section has the same configuration as that of the first embodiment except that the cooling section includes a flow path that goes up and down in the depth direction. Using the mold, vertical continuous casting was performed in the same manner as in the example. Cooling was adjusted by the speed of the refrigerant flowing through the flow path that went up and down in the depth direction inside the cooling section, and the flow rate of the cooling water was adjusted so that the upper temperature (corresponding to section A) was 850 ° C.
The drawing pattern of the cast piece was set by appropriately combining drawing, stopping, and retreating at a drawing speed of 70 mm / min.
As compared with Example 1, the hollow billet thus produced showed a difference in composition between the inner side and the outer side, but was not at a problematic level.

(Comparative Example 1)
As Comparative Example 1, the outer diameter of the upper end of the core is set to 129 mm and the outer diameter of the lower end of the core is set to 127 mm. However, the pull-out resistance was larger than 1 kN, and the pull-out could not be performed. Here, the shape of the core of Comparative Example 1 and Example 1 will be examined. Both are formed in a taper shape whose diameter decreases in accordance with the gradient of heat removal as it progresses from the upper end to the lower end of the core. Let the length of the core be x and the diameter be y. In Example 1, since the outer diameter of the upper end portion of the core is 129 mm and the outer diameter of the lower end portion of the core is 123 mm, the equation y = −0.03x + 129 is established. That is, the taper size of the core of Example 1 was 0.03. On the other hand, in Comparative Example 1, since the outer diameter of the upper end portion of the core is 129 mm and the outer diameter of the lower end portion of the core is 127 mm, the equation y = −0.01x + 129 is established. That is, the taper size of the core of Comparative Example 1 was 0.01. Thus, it was confirmed that when the size of the taper of the core is larger than 0.01, the cast piece is pulled out satisfactorily.

1, 31 Crucible 2, 32 Core 3, 3 ′ Outer cooling side 4, 34 Thermocouple protection tube insertion port 5, 35 Molten metal supply port 6, 36 Refrigerant probe insertion port 7 Casting outer peripheral unit 8, 38 Molten metal 9, 39 hollow billet 10 casting outer thermocouple 11 inner core thermocouple 12, 42 inert gas introduction part 13, 43 molten metal temperature measuring thermocouple 14 metal melting / holding part 15 core cooling part (inner side cooling) Part)
16, 17 Tubular hole 20 Vertical continuous casting mold 21 Channel 30 Hollow billet vertical continuous casting apparatus 33 Water-cooled copper jacket 44 Crucible temperature control thermocouple 45 Heater 46 Water-cooled probe 47 Pull-out mechanism

Claims (26)

  This is a facility for producing ingots of metal or inorganic compounds, where the continuous casting part is connected to the lower part of the part where the raw material is heated and melted, and the metal melting has the function of holding the molten metal obtained by melting and melting the raw material. -A continuous casting device for high-purity ingots in which the holding part and the outer peripheral part of the casting are integrated.   2. The high-purity ingot melting continuous casting apparatus according to claim 1, wherein the ingot has a hollow structure.   The high-purity ingot melting continuous casting apparatus according to claim 1 or 2, wherein the high-purity ingot is for a sputtering target.   The metal melting / holding portion having a function of holding the molten metal obtained by heating and melting the raw material and the casting outer peripheral portion are formed of a plurality of constituent pieces and / or a plurality of materials. Continuous casting equipment for purity ingots.   A core that is columnar and has a taper shape with a diameter exceeding 0.01 that decreases in accordance with the gradient of heat removal as it progresses downward, and the raw material located above the core is heated and melted. The molten metal from the metal melting / holding part having the function of melting the metal and holding the molten metal with the metal melting / holding part having a function of holding the molten metal and the outer peripheral surface of the core directly connected thereto The casting part which has a casting outer periphery which comprises the casting space which flows in, and has a casting part provided with the cooling part which cools the said casting space from the outer peripheral side and the inner peripheral side. A melting continuous casting apparatus for high-purity ingots according to claim 1.   The high-purity ingot melting and continuous casting apparatus according to claim 5, further comprising a cooling unit in the casting space from an outer peripheral side and an inner peripheral side.   The melt continuous casting of the high-purity ingot according to claim 6, wherein the cooling section is provided so as to cool the casting space by dividing it into a plurality of portions in the depth direction from the outer peripheral side and the inner peripheral side, respectively. apparatus.   The melting continuous casting apparatus for high-purity ingots according to claim 6 or 7, wherein the cooling section includes a flow path that moves up and down in the depth direction.   The cooling part which cools the said casting space from the outer peripheral side is provided in the outer peripheral side of the casting outer peripheral part of the metal melting | dissolving and holding | maintenance part which has the function to hold | maintain the molten metal which melt | dissolved and melt | dissolved the raw material. The high-purity ingot melting continuous casting apparatus according to any one of the above.   Refrigerant jacket provided with a plurality of small cooling parts in which the cooling part provided on the outer peripheral side of the casting outer peripheral part of the metal melting / holding part having a function of holding the molten metal obtained by heating and melting the raw material is divided in the depth direction The high-purity ingot melting continuous casting apparatus according to claim 9.   The high-purity ingot melting continuous casting apparatus according to claim 10, wherein each of the small cooling portions includes a path through which a refrigerant passes.   The high-purity ingot melting continuous casting apparatus according to claim 11, wherein the refrigerant is water.   The high-purity ingot melting continuous casting apparatus according to any one of claims 5 to 12, wherein a cooling unit for cooling the casting space from the inside is provided inside the core.   The cooling part provided in the inside of the core is configured by a concentric circle-shaped tubular hole part formed to extend in the depth direction, and a refrigerant probe inserted into the tubular hole part. The high-purity ingot melting continuous casting apparatus according to 13.   The high-purity ingot melting continuous casting apparatus according to claim 14, wherein the refrigerant used in the refrigerant probe is water.   The continuous melting of the high-purity ingot according to any one of claims 5 to 15, wherein the metal melting / holding portion and the core having a function of holding the molten material obtained by heating and melting the raw material are each formed of graphite. Casting equipment.   The thermocouple which measures the molten metal temperature of the molten metal supply site | part which supplies a molten metal to the said casting space from the metal melting | dissolving and holding | maintenance part which has the function to hold | maintain the molten metal which melt | dissolved the said raw material by heating is provided. The high-purity ingot melting continuous casting apparatus according to any one of the above.   A tubular hole extending in the depth direction is formed on the outer periphery of the casting of the metal melting / holding part having the function of holding the molten metal obtained by heating and melting the raw material, and a thermocouple is provided in the tubular hole. The high-purity ingot melting continuous casting apparatus according to any one of claims 5 to 17.   The thermocouple provided on the outer periphery of the casting of the metal melting / holding portion having the function of holding the molten metal obtained by heating and melting the raw material integrally has a plurality of temperature measurement points in the depth direction. The high-purity ingot melting continuous casting apparatus described.   20. The high-purity casting according to claim 18 or 19, wherein a plurality of the thermocouples are provided along a circumferential direction of a casting outer peripheral portion of a metal melting / holding portion having a function of holding the molten metal obtained by heating and melting the raw material. Mass melting continuous casting equipment.   The molten continuous casting of the high purity ingot according to any one of claims 5 to 20, wherein a tubular hole extending in the depth direction is formed in the core, and a thermocouple is provided in the tubular hole. apparatus.   The melting and continuous casting apparatus for high-purity ingots according to claim 21, wherein the thermocouple provided in the core has a plurality of temperature measurement points integrally in the depth direction.   23. The high-purity ingot melting continuous casting apparatus according to claim 21 or 22, wherein the thermocouple is provided at one or more locations along an outer peripheral direction of the core.   Each temperature measurement point of the thermocouple provided on the outer periphery of the casting of the metal melting / holding part having the function of holding the molten material obtained by heating and melting the raw material, and the thermocouple provided on the core is a mold. The melt continuous casting apparatus for high-purity ingots according to any one of claims 21 to 23, which is formed at the same position in the depth direction.   The high purity according to any one of claims 5 to 24, wherein an inert gas introduction part for introducing an inert gas is provided in a metal dissolving / holding part having a function of holding the molten material obtained by heating and melting the raw material. Ingot melting continuous casting equipment.   The melting continuous casting apparatus according to any one of claims 1 to 25, further comprising a step of cooling the molten metal that has flowed into the casting space from a metal melting / holding unit having a function of retaining the molten metal by melting the raw material by heating. Melting continuous casting method of high purity ingot using