WO2014057903A1 - Mold for precision casting, and method for producing same - Google Patents

Mold for precision casting, and method for producing same Download PDF

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Publication number
WO2014057903A1
WO2014057903A1 PCT/JP2013/077218 JP2013077218W WO2014057903A1 WO 2014057903 A1 WO2014057903 A1 WO 2014057903A1 JP 2013077218 W JP2013077218 W JP 2013077218W WO 2014057903 A1 WO2014057903 A1 WO 2014057903A1
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WO
WIPO (PCT)
Prior art keywords
mold
slurry
layer
precision casting
stucco
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Application number
PCT/JP2013/077218
Other languages
French (fr)
Japanese (ja)
Inventor
英隆 小熊
一剛 森
岡田　郁生
幸郎 下畠
Original Assignee
三菱重工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 三菱重工業株式会社 filed Critical 三菱重工業株式会社
Priority to DE112013004945.7T priority Critical patent/DE112013004945T5/en
Priority to US14/433,056 priority patent/US20150283601A1/en
Publication of WO2014057903A1 publication Critical patent/WO2014057903A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
    • B22C7/02—Lost patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/06—Permanent moulds for shaped castings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/06—Permanent moulds for shaped castings
    • B22C9/061—Materials which make up the mould

Definitions

  • the present invention relates to a precision casting mold and a manufacturing method thereof.
  • a casting method for producing a casting there is a precision casting method used when producing a casting with high accuracy.
  • slurry is applied around a vanishing model (wax mold) having the same shape as the molded part, and then the first layer stucco (flower) is adhered and dried. Let Thereafter, the three steps of slurry application, stucco attachment, and drying are repeated to produce a mold (outer mold) that covers the outside of the casting.
  • a wax mold is attached to a slurry mainly composed of silica sol, and the slurry is attached to the surface of the wax mold and dried. Since only a small amount of slurry adheres to each operation and only a thin slurry can be formed, the thickness is increased by repeating several times to 10 to several times. Also, coarse particles called stucco material are sprinkled on and adhered to the surface of the slurry in order to speed up drying or to ensure a quick wall thickness in order to prevent dry cracking. Therefore, the mold cross-sectional structure is a dense layer and a layer of coarse particles.
  • silica sol is a liquid in which spherical silica particles having a particle diameter of about 20 nm are dispersed.
  • the silica ultrafine particles adhere to the surface of relatively fine particles (several to several tens of microns) and coarse particles (stucco) (several hundred microns to several mm) such as zircon and alumina contained in the slurry during the drying process.
  • a mold using the above-mentioned silica sol (a liquid in which ultrafine particles of silica are dispersed) is sufficient.
  • a molten metal is used to control the crystal precipitation direction. Hold.
  • the holding time at a high temperature for example, about 1550 ° C.
  • silica as a binder is softened and the mold is deformed.
  • the mold is placed in a heater in a vacuum, heated and held at a temperature above the melting point of the molten metal, the molten metal is injected into the mold, and the mold is moved downward from the heater.
  • the molten metal is manufactured by cooling and solidifying from one direction below by pulling out while controlling the pulling down.
  • the present invention has been made in view of the above, and an object thereof is to provide a precision casting mold that does not deform even when kept at a high temperature for a long time, and a method for manufacturing the same.
  • a first invention of the present invention for solving the above-described problems is a precision casting mold used for manufacturing a casting, wherein the core has a shape corresponding to a hollow portion inside the casting, and an outer peripheral surface of the casting.
  • An outer mold corresponding to the shape of the mold, and the outer mold is formed on the inner peripheral surface, and uses a casting slurry for precision casting made of ultra-fine alumina particles having a particle size of 1.0 ⁇ m or less.
  • the present invention provides a precision casting mold comprising a dried backup layer and a multilayer backup layer formed a plurality of times.
  • the precision casting mold slurry includes any one of zircon powder and alumina powder having an average particle size of 50 ⁇ m or less, and the stucco material has an average particle size of 0.5 mm.
  • the present invention provides a precision casting mold characterized by being one of the above zircon stucco grains and alumina stucco grains.
  • a third invention is the precision casting mold according to the first or second invention, wherein the prime layer has a stucco layer in which a stucco material is adhered to a slurry layer made of precision casting mold slurry. .
  • a fourth invention is a method of manufacturing a precision casting mold used for manufacturing a casting, wherein the precision casting wax mold is for precision casting made of ultra-fine alumina particles having a particle size of 1.0 ⁇ m or less.
  • a mold sintering step to obtain a mold, a.
  • a stucco layer is formed by adhering a stucco material to the slurry layer comprising the precision casting mold slurry in the first film forming step, and then drying. It is in the manufacturing method of the mold for precision casting characterized by the above.
  • the sixth invention is the method for producing a precision casting mold according to the fourth or fifth invention, wherein the precision casting mold slurry dispersant is a polycarboxylate.
  • the heat resistant temperature is improved with respect to the conventional use of silica sol. Even when held for a long time, there is an effect that a mold in which deformation is suppressed can be obtained.
  • FIG. 1 is a configuration diagram of a dry molded body serving as an outer mold.
  • FIG. 2 is a configuration diagram of a dry molded body serving as an outer mold.
  • FIG. 3 is a diagram showing the relationship between particle size and strength.
  • FIG. 4 is a diagram showing the particle size distribution of alumina fine particles.
  • FIG. 5 is a flowchart showing an example of the steps of the casting method.
  • FIG. 6 is a flowchart showing an example of the steps of the mold manufacturing method.
  • FIG. 7 is an explanatory view schematically showing a core manufacturing process.
  • FIG. 8 is a perspective view schematically showing a part of the mold.
  • FIG. 9 is an explanatory view schematically showing a wax mold manufacturing process.
  • FIG. 1 is a configuration diagram of a dry molded body serving as an outer mold.
  • FIG. 2 is a configuration diagram of a dry molded body serving as an outer mold.
  • FIG. 3 is a diagram showing the relationship between particle size and strength.
  • FIG. 10 is an explanatory diagram schematically showing a configuration in which slurry is applied to a wax mold.
  • FIG. 11 is an explanatory view schematically showing a manufacturing process of the outer mold.
  • FIG. 12 is an explanatory view schematically showing a part of the mold manufacturing method.
  • FIG. 13 is an explanatory view schematically showing a part of the casting method.
  • FIG. 1 is a configuration diagram of a dry molded body serving as an outer mold.
  • FIG. 2 is a configuration diagram of another dry molded body serving as an outer mold.
  • the precision casting mold is a precision casting mold used for manufacturing a casting, and corresponds to the shape of the core corresponding to the hollow portion inside the casting and the shape of the outer peripheral surface of the casting.
  • a casting slurry for precision casting made of ultra-fine alumina (Al 2 O 3 ) particles formed on the inner peripheral surface and having a particle size of 1.0 ⁇ m or less.
  • a prime layer (first dry film) 101A made of a slurry film dried by using a slurry, and a slurry layer 102 made of the precision casting mold slurry and formed outside the prime layer (first dry film) 101A;
  • a first backup layer (second dry film) 104-1 formed by a stucco layer 103 having a stucco material adhered to the slurry layer 102 and dried; It is made of.
  • the high-purity ultrafine alumina particles which are the binder for forming the slurry in the present invention
  • alumina ultrafine particles which are the binder for forming the slurry in the present invention
  • the term “monodispersed” refers to a state in which, for example, when a slurry is formed using alumina fine particles having a particle diameter of about 0.5 ⁇ m, the result of the dispersion treatment is also monodispersed to 0.5 ⁇ m.
  • the particle diameter of the alumina fine particles is 1.0 ⁇ m or less, more preferably in the range of 0.3 to 0.5 ⁇ m.
  • the reason why the alumina fine particles are preferably 1.0 ⁇ m or less is that if it exceeds 1.0 ⁇ m, the result of the bending test strength is not preferable.
  • FIG. 3 is a diagram showing the relationship between particle size and strength. As shown in FIG. 3, when the particle diameter exceeds 1.0 ⁇ m, the desired strength cannot be ensured, which is not preferable.
  • Zircon powder (for example, 350 mesh) is added as flour to the single dispersed alumina fine particle binder to obtain a precision casting mold slurry. In the present invention, it is acceptable to add no flour.
  • polycarboxylate for example, ammonium salt
  • dispersant for example, ammonium salt
  • dispersing means for example, a ball mill using balls having a diameter of 10 to 20 mm can be exemplified, but the dispersing means is not limited to this as long as it is a single dispersing means.
  • FIG. 4 is a diagram showing the particle size distribution of alumina fine particles.
  • the single dispersion it is necessary that the particle size distribution is narrow, and as shown in FIG. 4, the dispersion is such that the distribution falls within the range of 0.8d to 1.2d from the center particle size (d). Is preferred.
  • the particle size distribution was measured by the following apparatus.
  • a laser scattering / diffraction type particle size distribution measuring device manufactured by Aisin Nano Technologies, Inc., “CILAS 850B type” was used.
  • the mold 30 for precision casting (hereinafter referred to as “slurry”) made of ultrafine alumina particles is used to immerse the wax mold 30 and lift it to drop excess slurry. Thereafter, a slurry film (first dry film) is obtained on the surface of the wax mold 30 by drying. This slurry film becomes a prime layer 101A in contact with the surface of the wax mold 30 in FIG.
  • the same operation as the second film forming step of the first backup layer 104-1 is repeated a plurality of times (for example, 6 to 10 times), and the slurry layer (n + 1 layer) 102 and the stucco layer (n layer) 103 are alternately arranged.
  • a dry molded body 106A serving as an outer mold having a multilayer backup layer 105A having a predetermined thickness laminated on the substrate is obtained.
  • This dried molded body is put into an autoclave at 150 ° C., for example, and the wax constituting the wax mold 30 is melted and discharged. Thereafter, this mold is heat-treated at 1,000 ° C. to obtain a precision casting mold.
  • the obtained mold for precision casting was high in strength without deformation in a 1500 ° C. strength test, as shown in a test example described later. On the other hand, the softening behavior was confirmed using the conventional silica sol.
  • a stucco material may be attached to the prime slurry layer 101a to form the prime stucco layer 101b, and then dried to form the prime layer 101B.
  • the number of times that the slurry layer of the multilayer backup layer 105B is stacked and the number of times that the stucco layer 103 is stacked are the same number (n layers).
  • a dry molded body 106B serving as an outer mold having the layer backup layer 105B is obtained.
  • zircon powder was used as the flour, but in addition to zircon powder, alumina powder was used, and even if alumina stucco particles were used instead of zircon stucco particles, the same precision casting mold was obtained. Can do.
  • the relationship between the flour and the stucco material is not limited, and either zircon powder or alumina powder is used as the flour, and either zircon stucco particle or alumina stucco particle is used as the stucco material. Just do it.
  • the particle size of the flour is 350 mesh, but the present invention is not limited to this.
  • the stucco particles have a particle size of 0.8 mm, but the present invention is not limited to this. For example, particles having a diameter of about 0.4 mm to 2 mm and an average particle size of 0.5 mm or more should be used. Is preferred.
  • FIG. 5 is a flowchart showing an example of the steps of the casting method.
  • the casting method will be described with reference to FIG.
  • the processing shown in FIG. 5 may be executed fully automatically, or may be executed by an operator operating an apparatus that executes each process.
  • the casting method of this embodiment produces a casting mold (step S1).
  • the mold may be produced in advance or may be produced each time casting is performed.
  • FIG. 6 is a flowchart showing an example of the steps of the mold manufacturing method.
  • the process shown in FIG. 6 may be executed fully automatically, or may be executed by an operator operating an apparatus that executes each process.
  • the mold manufacturing method produces a core (core) (step S12).
  • a core is a shape corresponding to the cavity inside the casting produced with a casting_mold
  • FIG. 7 is an explanatory view schematically showing a core manufacturing process.
  • a mold 12 is prepared as shown in FIG. 7 (step S101).
  • the mold 12 has a hollow area corresponding to the core.
  • the portion that becomes the cavity of the core becomes the convex portion 12a.
  • the cross section of the mold 12 is shown.
  • the mold 12 basically covers the entire circumference of the region corresponding to the core except for an opening for injecting material into the space and a hole for extracting air. It is hollow.
  • the ceramic slurry 16 is injected into the mold 12 through an opening for injecting material into the space of the mold 12 as indicated by an arrow 14.
  • the core 18 is produced by so-called injection molding in which the ceramic slurry 16 is injected into the mold 12.
  • the core 18 is produced inside the mold 12, the core 18 is removed from the mold 12, and the removed core 18 is placed in the firing furnace 20 and fired. Thereby, the core 18 made of ceramic is baked and hardened (step S102).
  • the core 18 is produced as described above.
  • the core 18 is formed of a material that can be removed by a decore process such as a chemical process after the casting is solidified.
  • an external mold is manufactured (step S14).
  • the outer mold has a shape in which the inner peripheral surface corresponds to the outer peripheral surface of the casting.
  • the mold may be made of metal or ceramic.
  • FIG. 8 is a perspective view schematically showing a part of the mold. As for the metal mold
  • FIG. 9 is an explanatory view schematically showing a wax mold manufacturing process.
  • the core 18 is installed at a predetermined position of the mold 22a (step S110).
  • a mold 22b corresponding to the mold 22a is placed on the surface of the mold 22a where the recess is formed, the core 18 is surrounded by the molds 22a and 22b, and the core 18 and the molds 22a and 22b are separated.
  • a space 24 is formed therebetween.
  • the mold manufacturing method starts injection of WAX 28 from the pipe connected to the space 24 toward the inside of the space 24 as indicated by an arrow 26 (step S112).
  • WAX 28 is a substance having a relatively low melting point, such as wax, which melts when heated above a predetermined temperature.
  • the entire space 24 is filled with the WAX 28 (step S113).
  • the wax 28 is solidified to form the wax mold 30 in which the WAX 28 surrounds the core 18.
  • the wax mold 30 basically has the same shape as the casting for which the part formed by the WAX 28 is manufactured.
  • the wax mold 30 is separated from the molds 22a and 22b, and the gate 32 is attached (step S114).
  • the gate 32 is a port into which molten metal, which is a metal melted during casting, is charged.
  • the mold manufacturing method produces the wax mold 30 including the core 18 inside and formed of the WAX 28 having the same shape as the casting.
  • FIG. 10 is an explanatory diagram schematically showing a configuration in which slurry is applied to a wax mold.
  • the wax mold 30 is immersed in the storage part 41 in which the slurry 40 is stored, and is taken out and then dried (step S19).
  • the prime layer 101 ⁇ / b> A can be formed on the surface of the wax mold 30.
  • the slurry applied in step S ⁇ b> 18 is a slurry applied directly to the wax mold 30.
  • the slurry 40 a slurry in which alumina ultrafine particles are monodispersed is used.
  • refractory fine particles of about 350 mesh such as zirconia, as flour.
  • polycarboxylate as a dispersing agent.
  • slurry application is performed with the slurry 40, and then the solder mold having the prime layer (first dry film) 101A is further applied with slurry (dipping) (step S20).
  • stuccoing is performed by sprinkling zircon stucco grains (average particle size 0.8 mm) as the stucco material 54 on the surface of the wet slurry (step S21). Thereafter, the slurry layer with the stucco material attached thereto was dried to form the first backup layer (second dry film) 104-1 on the prime layer (first dry film) 101A (step S22).
  • a predetermined number (n) of n-th backup layers 104-n are stacked (step S23: Yes) to obtain a dry molded body 106A that is an outer mold having a thickness of, for example, 10 mm on which the multilayer backup layer 105A is formed.
  • step S24 the dry molded body 106A is subjected to heat treatment (step S24). Specifically, WAX between the outer mold and the core is removed, and the outer mold and the core are further fired.
  • FIG. 12 is an explanatory view schematically showing a part of the mold manufacturing method.
  • a dry molded body 106A serving as an outer mold in which a plurality of layers of the prime layer 101A and the multilayer backup layer 105A is formed is placed in the autoclave 60 and heated.
  • the autoclave 60 heats the wax mold 30 in the dry molded body 106A by filling the interior with pressurized steam. As a result, the WAX constituting the wax mold 30 is melted, and the molten WAX 62 is discharged from the space 64 surrounded by the dry molded body 106A. In the mold manufacturing method, the melted WAX 62 is discharged from the space 64, so that, as shown in step S131, an area filled with WAX between the dry molded body 106A serving as the outer mold and the core 18 is filled with the space 64. A mold 72 in which is formed is produced.
  • step S132 the mold 72 in which the space 64 is formed between the dry molded body 106A serving as the outer mold and the core 18 is heated in the firing furnace 70.
  • the mold 72 removes the water component and unnecessary components contained in the dry molded body 106 ⁇ / b> A serving as the outer mold, and is further cured by firing to form the outer mold 61.
  • the mold 72 is produced as described above.
  • FIG. 13 is an explanatory view schematically showing a part of the casting method.
  • the mold is preheated (step S2).
  • the mold 72 is placed in a furnace (vacuum furnace, firing furnace) and heated to 800 ° C. or higher and 900 ° C. or lower.
  • a furnace vacuum furnace, firing furnace
  • preheating it is possible to prevent the mold from being damaged when molten metal (melted metal) is injected into the mold at the time of casting production.
  • step S3 when the mold is preheated, pouring is performed (step S3). That is, as shown in step S ⁇ b> 140 of FIG. 13, molten metal 80, that is, a molten casting material (for example, steel) is injected between the outer mold 61 and the core 18 from the opening of the mold 72.
  • molten metal 80 that is, a molten casting material (for example, steel) is injected between the outer mold 61 and the core 18 from the opening of the mold 72.
  • step S4 After the molten metal 80 poured into the mold 72 is solidified, the outer mold 61 is removed (step S4). That is, as shown in step S141 in FIG. 13, when the molten metal 80 is solidified into the casting 90 inside the mold 72, the outer mold 61 is crushed and removed from the casting 90 as broken pieces 61a.
  • the core removal process is performed (step S5). That is, as shown in step S142 of FIG. 13, the casting 90 is put into the autoclave 92 and the core removal process is performed by melting the core 18 inside the casting 90, and the melted melting core 94 is converted into the casting 90 of the casting 90. Drain from inside. Specifically, the casting 90 is put into an alkaline solution inside the autoclave 92, and the melting core 94 is discharged from the casting 90 by repeating pressurization and decompression.
  • a finishing process is performed (step S6). That is, a finishing process is performed on the surface and inside of the casting 90. In the casting method, the casting is inspected together with the finishing process. Thereby, as shown to step S143 of FIG. 13, the casting 100 can be manufactured.
  • a casting mold is manufactured by using a lost wax casting method using WAX (wax).
  • the mold manufacturing method, the casting method, and the mold according to the present embodiment include an outer mold that is an outer portion of the mold, and a prime layer (first layer that is the first layer) that forms an inner peripheral surface using alumina ultrafine particles as a slurry.
  • (Dry film) 101A is formed, and a plurality of backup layers 105A are formed outside the prime layer 101A to form a multilayer structure.
  • the prime layer 101B including the slurry layer 101a to which the stucco material is added and the stucco layer 101b may be used as the prime layer (see FIG. 2).
  • the wax mold before the outer mold is formed is a member having a width of 30 mm, a thickness of 8 mm, and a length of 300 mm, and this wax mold has a prime layer (first dry film) made of a slurry layer, A mold was prepared by forming a multilayer backup layer of slurry and stucco material.
  • a slurry of high-purity ultrafine alumina (Al 2 O 3 , specific surface area 10 m 2 / g, particle size of about 0.5 ⁇ m) is kneaded for 24 hours using a polycarboxylate as a dispersant and using a ball mill. An alumina slurry was obtained. The solid content concentration of the obtained alumina slurry is 50 wt%. In this alumina slurry, as a result of the dispersion treatment, it was confirmed that the alumina particles were monodispersed to 0.5 ⁇ m. To this alumina slurry, 350 mesh zircon powder was added as flour to prepare a precision casting mold slurry. At the same time, 0.01% silicon-based antifoaming agent and 0.01% wettability improving agent were added to prepare slurry for use.
  • a wax body with a width of 30 mm, a thickness of 8 mm, and a length of 300 mm, immerse the wax body in the obtained use slurry, pull it up and attach the use slurry to the wax surface, then drop the excess use slurry, By drying, a slurry prime layer (first dry film) was obtained on the surface of the wax body.
  • the wax body having the prime layer was immersed in the use slurry, and then the excess use slurry was dropped.
  • Zircon stucco grains having an average grain size of 0.8 mm were adhered to the wet slurry and then dried to form a second dry film (first backup layer).
  • test A strength test piece of 10 mm ⁇ 50 mm and a thickness of 5 mm was processed from the obtained mold of Example 1 and the comparative mold, and a high-temperature strength test was performed. In the strength test at 1500 ° C., the softening behavior was confirmed using the conventional silica sol. As a result, the test piece of the comparative example was not clearly cut and bent. On the other hand, the test piece using the alumina slurry of this example (zircon grains as the stucco material) was not deformed and was broken at 100 MPa.
  • the strength test was performed according to “Bending strength of ceramics (1981)” according to JIS R 1601.
  • the binder is a slurry of ultrafine alumina with a high heat resistance (melting point 2,070 ° C.) and the stucco material is a zircon grain (melting point 2,715 ° C.), so that the conventional silica sol is used.
  • the heat-resistant temperature was improved, and a mold that did not deform even when kept at a high temperature (1,550 ° C.) for a long time in the production of a unidirectionally solidified blade could be obtained.
  • Example 2 In Example 1, 350 mesh alumina powder was added as flour instead of zircon powder to obtain a precision casting mold slurry. Further, a mold of Example 2 was obtained in the same manner as in Example 1 except that alumina stucco particles having an average particle diameter of 0.8 mm were used as the stucco material.
  • test A strength test piece of 10 mm ⁇ 50 mm and a thickness of 5 mm was processed from the obtained mold of Example 2 and the mold of Comparative Example, and the same high-temperature strength test as in Example 1 was performed.
  • the test piece using the alumina slurry of this example (alumina particles as the stucco material) was not deformed and was broken at 100 MPa.
  • the binder was made into a slurry of ultrafine alumina (melting point 2,070 ° C.) with high heat resistance, and the stucco material was made into alumina particles (melting point 2,070 ° C.).
  • the heat-resistant temperature was improved, and a mold that could not be deformed even when kept at a high temperature (1,550 ° C.) for a long time in the production of a unidirectionally solidified blade could be obtained.
  • the obtained mold can be obtained as compared with the case where a conventional silica sol is used.
  • the heat resistant temperature of the unidirectional solidified blade was improved, and a mold that did not deform even when kept at a high temperature (1,550 ° C.) for a long time in the production of a unidirectionally solidified blade could be obtained.

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  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Mold Materials And Core Materials (AREA)

Abstract

A mold for precision casting which is used to produce a casting, the mold having a core which has a shape corresponding to the hollow section in the interior of the casting, and an outer mold which has a shape corresponding to the outer circumferential surface of the casting, wherein the outer mold comprises: a prime layer (101A) which is formed on the inner circumferential surface from a slurry film obtained by drying a mold slurry for precision casting comprising monodispersed aluminum superfine particles having a diameter of 1.0 μm or less; and a multi-layered back-up layer (105A) which is formed on the outside of the prime layer (101A) by forming multiple back-up layers (104) obtained by forming and drying slurry layers (102) formed from the mold slurry for precision casting, and stucco layers (103) obtained by attaching a stucco material on the slurry layers (102).

Description

精密鋳造用鋳型及びその製造方法Precision casting mold and manufacturing method thereof
　本発明は、精密鋳造用鋳型及びその製造方法に関するものである。 The present invention relates to a precision casting mold and a manufacturing method thereof.
　鋳物を製造する鋳造方法には、鋳物を高い精度で製造する場合に用いられる精密鋳造方法がある。精密鋳造方法は、特許文献１に記載されているように、成形部品と同一形状の消失性模型（ワックス型）の周囲にスラリーを塗布し、その後、初層スタッコ（フラワー）を付着させ、乾燥させる。その後、スラリーの塗布、スタッコの付着、乾燥の３つの工程を繰返し行い、鋳物の外側を覆う型（外側鋳型）を作製する。 As a casting method for producing a casting, there is a precision casting method used when producing a casting with high accuracy. As described in Patent Document 1, in the precision casting method, slurry is applied around a vanishing model (wax mold) having the same shape as the molded part, and then the first layer stucco (flower) is adhered and dried. Let Thereafter, the three steps of slurry application, stucco attachment, and drying are repeated to produce a mold (outer mold) that covers the outside of the casting.
　ここで、精密鋳造用鋳型はシリカゾルを主体とするスラリーにワックス型を付け込み、ワックス型の表面にスラリーを付着させ乾燥させる。
　１回の操作では付着するスラリーが少なく、薄いものしかできないので、数回～１０数回繰返して厚さを稼いでいる。また、乾燥を早くするため、あるいは、早く肉厚を確保するため、乾燥割れを防止するため、スタッコ材と呼ばれる粗い粒子をスラリー表面にふりかけ、付着させている。そのため、鋳型の断面構造は緻密層、粗い粒子の層の繰り返しとなっている。
　例えばシリカゾルは粒径２０ｎｍ程度の球状シリカ粒子が分散された液である。このシリカ超微粒子が、乾燥の過程でスラリーに含まれるジルコン、アルミナなどの比較的細かい粒子（数ミクロンから数十ミクロン）及び粗い粒子（スタッコ）（数百ミクロン～数ｍｍ）の表面に付着し、乾燥、熱処理により固く結合することにより、鋳型の形状が保たれると同時に強度を保有し、鋳型として利用できるようになっている。 Here, in the precision casting mold, a wax mold is attached to a slurry mainly composed of silica sol, and the slurry is attached to the surface of the wax mold and dried.
Since only a small amount of slurry adheres to each operation and only a thin slurry can be formed, the thickness is increased by repeating several times to 10 to several times. Also, coarse particles called stucco material are sprinkled on and adhered to the surface of the slurry in order to speed up drying or to ensure a quick wall thickness in order to prevent dry cracking. Therefore, the mold cross-sectional structure is a dense layer and a layer of coarse particles.
For example, silica sol is a liquid in which spherical silica particles having a particle diameter of about 20 nm are dispersed. The silica ultrafine particles adhere to the surface of relatively fine particles (several to several tens of microns) and coarse particles (stucco) (several hundred microns to several mm) such as zircon and alumina contained in the slurry during the drying process. By firmly bonding by drying and heat treatment, the shape of the mold is maintained, and at the same time, the strength is maintained and the mold can be used as a mold.
特開２００１－１８０３３号公報JP 2001-18033 A
　ところで、一般的には、前述のシリカゾル（シリカの超微粒子を分散した液）を用いた鋳型で十分であるが、例えば一方向凝固翼製造などでは、結晶の析出方向を制御するため、溶融金属を保持する。この結果、高温（例えば１５５０℃程度）での保持時間が長くなる。この場合、高温で保持されるため、バインダであるシリカが軟化して、鋳型の変形を生じてしまう、という問題がある。 By the way, in general, a mold using the above-mentioned silica sol (a liquid in which ultrafine particles of silica are dispersed) is sufficient. For example, in manufacturing a unidirectional solidified blade, a molten metal is used to control the crystal precipitation direction. Hold. As a result, the holding time at a high temperature (for example, about 1550 ° C.) becomes longer. In this case, since it is held at a high temperature, there is a problem that silica as a binder is softened and the mold is deformed.
　ここで、一方向凝固翼製造などでは、鋳型を真空中のヒーター内に設置し、溶融金属の融点以上の温度に加熱保持して、鋳型中に溶融金属を注入し、鋳型をヒーターから下方へ引き下げを制御しながら引き抜くことにより、溶融金属を下方の一方向から冷却、凝固させることにより製造されるのが一般的である。 Here, in the production of unidirectional solidified blades, the mold is placed in a heater in a vacuum, heated and held at a temperature above the melting point of the molten metal, the molten metal is injected into the mold, and the mold is moved downward from the heater. Generally, the molten metal is manufactured by cooling and solidifying from one direction below by pulling out while controlling the pulling down.
　よって、例えば一方向凝固翼製造等において、高温（例えば１５５０℃程度）での長時間に亙って保持した場合でも変形が抑制される鋳型の出現が切望されている。 Therefore, for example, in the production of unidirectional solidified blades, there is an urgent need for the appearance of a mold capable of suppressing deformation even when held at a high temperature (for example, about 1550 ° C.) for a long time.
　本発明は、上記に鑑みてなされたものであって、高温で長時間保持した場合でも変形が生じない精密鋳造用鋳型及びその製造方法を提供することを目的とする。 The present invention has been made in view of the above, and an object thereof is to provide a precision casting mold that does not deform even when kept at a high temperature for a long time, and a method for manufacturing the same.
　上述した課題を解決するための本発明の第１の発明は、鋳物の製造に用いる精密鋳造用鋳型であって、前記鋳物の内部の空洞部分に対応する形状のコアと、前記鋳物の外周面の形状に対応する外側鋳型と、を有し、前記外側鋳型は、内周面に形成され、粒径１．０μｍ以下の単一分散してなるアルミナ超微粒子からなる精密鋳造用鋳型スラリーを用いて乾燥してなるスラリー膜からなるプライム層と、前記プライム層の外側に形成され、前記精密鋳造用鋳型スラリーからなるスラリー層と、該スラリー層にスタッコ材を付着したスタッコ層とにより形成し、乾燥してなるバックアップ層を、複数回形成してなる複層バックアップ層と、からなることを特徴とする精密鋳造用鋳型にある。 A first invention of the present invention for solving the above-described problems is a precision casting mold used for manufacturing a casting, wherein the core has a shape corresponding to a hollow portion inside the casting, and an outer peripheral surface of the casting. An outer mold corresponding to the shape of the mold, and the outer mold is formed on the inner peripheral surface, and uses a casting slurry for precision casting made of ultra-fine alumina particles having a particle size of 1.0 μm or less. Formed by a prime layer made of a slurry film formed by drying, a slurry layer formed on the outside of the prime layer, made of the mold slurry for precision casting, and a stucco layer with a stucco material attached to the slurry layer, The present invention provides a precision casting mold comprising a dried backup layer and a multilayer backup layer formed a plurality of times.
　第２の発明は、第１の発明において、前記精密鋳造用鋳型スラリーに平均粒径が５０μｍ以下のジルコン粉、アルミナ粉をいずれか一方を含み、前記スタッコ材が、平均粒径が０．５ｍｍ以上のジルコンスタッコ粒、アルミナスタッコ粒のいずれか一方であることを特徴とする精密鋳造用鋳型にある。 According to a second invention, in the first invention, the precision casting mold slurry includes any one of zircon powder and alumina powder having an average particle size of 50 μm or less, and the stucco material has an average particle size of 0.5 mm. The present invention provides a precision casting mold characterized by being one of the above zircon stucco grains and alumina stucco grains.
　第３の発明は、第１又は２の発明において、前記プライム層が、精密鋳造用鋳型スラリーからなるスラリー層に、スタッコ材を付着したスタッコ層を有することを特徴とする精密鋳造用鋳型にある。 A third invention is the precision casting mold according to the first or second invention, wherein the prime layer has a stucco layer in which a stucco material is adhered to a slurry layer made of precision casting mold slurry. .
　第４の発明は、鋳物の製造に用いる精密鋳造用鋳型の製造方法であって、精密鋳造用ろう型を、粒径１．０μｍ以下の単一分散してなるアルミナ超微粒子からなる精密鋳造用鋳型スラリーに浸漬し、引き上げた後乾燥して、ろう型の表面にスラリー膜からなるプライム層を形成する第１成膜工程と、前記プライム層を形成したろう型を、前記精密鋳造用鋳型スラリーに浸漬し、引き上げた後、スラリー表面にスタッコ材を振掛け、その後乾燥してバックアップ層を形成する第２成膜工程と、前記第２成膜工程のバックアップ層を形成する工程を複数回繰り返し、複層バックアップ層を形成した成形体を得る成形体形成工程と、得られた成形体からろう型のワックスを融解・除去する脱ワックス工程と、脱ワックス後の成形体を焼成処理し、鋳型を得る鋳型焼成工程と、を有することを特徴とする精密鋳造用鋳型の製造方法にある。 A fourth invention is a method of manufacturing a precision casting mold used for manufacturing a casting, wherein the precision casting wax mold is for precision casting made of ultra-fine alumina particles having a particle size of 1.0 μm or less. First casting step of forming a prime layer composed of a slurry film on the surface of the wax mold by dipping in the mold slurry, lifting and drying, and the mold casting slurry for forming the prime layer into the mold slurry for precision casting 2nd film forming step in which the stucco material is sprinkled on the slurry surface and then dried to form a backup layer, and the step of forming the backup layer in the second film forming step is repeated a plurality of times. , A molded body forming step for obtaining a molded body in which a multilayer backup layer is formed, a dewaxing step for melting and removing wax-type wax from the obtained molded body, and firing the molded body after dewaxing, In the production method of precision casting mold, characterized in that it comprises a mold sintering step to obtain a mold, a.
　第５の発明は、第４の発明において、前記第１成膜工程の際、前記精密鋳造用鋳型スラリーからなるスラリー層に、スタッコ材を付着してスタッコ層を形成し、その後乾燥することを特徴とする精密鋳造用鋳型の製造方法にある。 According to a fifth invention, in the fourth invention, a stucco layer is formed by adhering a stucco material to the slurry layer comprising the precision casting mold slurry in the first film forming step, and then drying. It is in the manufacturing method of the mold for precision casting characterized by the above.
　第６の発明は、第４又は５の発明において、前記精密鋳造用鋳型スラリーの分散剤がポリカルボン酸塩であることを特徴とする精密鋳造用鋳型の製造方法にある。 The sixth invention is the method for producing a precision casting mold according to the fourth or fifth invention, wherein the precision casting mold slurry dispersant is a polycarboxylate.
　本発明は、耐熱性が高いアルミナ超微粒子を用いてスラリーとすることで、従来のシリカゾル使用に対して耐熱温度が向上し、例えば一方向凝固翼製造等における高温（例えば１５５０℃）で長時間に亙って保持した場合でも変形が抑制される鋳型が得られる、という効果を奏する。 In the present invention, by using an ultrafine alumina particle having high heat resistance as a slurry, the heat resistant temperature is improved with respect to the conventional use of silica sol. Even when held for a long time, there is an effect that a mold in which deformation is suppressed can be obtained.
図１は、外側鋳型となる乾燥成形体の構成図である。FIG. 1 is a configuration diagram of a dry molded body serving as an outer mold. 図２は、外側鋳型となる乾燥成形体の構成図である。FIG. 2 is a configuration diagram of a dry molded body serving as an outer mold. 図３は、粒径と強度との関係を示す図である。FIG. 3 is a diagram showing the relationship between particle size and strength. 図４は、アルミナ微粒子の粒度分布を示す図である。FIG. 4 is a diagram showing the particle size distribution of alumina fine particles. 図５は、鋳造方法の工程の一例を示すフローチャートである。FIG. 5 is a flowchart showing an example of the steps of the casting method. 図６は、鋳型製造方法の工程の一例を示すフローチャートである。FIG. 6 is a flowchart showing an example of the steps of the mold manufacturing method. 図７は、コアの製造工程を模式的に示す説明図である。FIG. 7 is an explanatory view schematically showing a core manufacturing process. 図８は、金型の一部を模式的に示す斜視図である。FIG. 8 is a perspective view schematically showing a part of the mold. 図９は、ろう型の製造工程を模式的に示す説明図である。FIG. 9 is an explanatory view schematically showing a wax mold manufacturing process. 図１０は、ろう型にスラリーを塗布する構成を模式的に示す説明図である。FIG. 10 is an explanatory diagram schematically showing a configuration in which slurry is applied to a wax mold. 図１１は、外側鋳型の製造工程を模式的に示す説明図である。FIG. 11 is an explanatory view schematically showing a manufacturing process of the outer mold. 図１２は、鋳型製造方法の一部工程を模式的に示す説明図である。FIG. 12 is an explanatory view schematically showing a part of the mold manufacturing method. 図１３は、鋳造方法の一部工程を模式的に示す説明図である。FIG. 13 is an explanatory view schematically showing a part of the casting method.
　以下、本発明につき図面を参照しつつ詳細に説明する。なお、以下の説明により本発明が限定されるものではない。また、以下の説明における構成要素には、当業者が容易に想定できるもの、実質的に同一のもの、いわゆる均等の範囲のものが含まれる。 Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. In addition, constituent elements in the following description include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range.
　図１は、外側鋳型となる乾燥成形体の構成図である。図２は、外側鋳型となる他の乾燥成形体の構成図である。
　図１に示すように、精密鋳造用鋳型は、鋳物の製造に用いる精密鋳造用鋳型であって、前記鋳物の内部の空洞部分に対応する形状のコアと、前記鋳物の外周面の形状に対応する外側鋳型と、を有し、前記外側鋳型は、内周面に形成され、粒径１．０μｍ以下の単一分散してなるアルミナ（Ａｌ2Ｏ3）超微粒子からなる精密鋳造用鋳型スラリーを用いて乾燥してなるスラリー膜からなるプライム層（第１乾燥膜）１０１Ａと、前記プライム層（第１乾燥膜）１０１Ａの外側に形成され、前記精密鋳造用鋳型スラリーからなるスラリー層１０２と、該スラリー層１０２にスタッコ材を付着したスタッコ層１０３とにより形成し、乾燥してなる第１バックアップ層（第２乾燥膜）１０４－１を、複数回形成してなる複層バックアップ層１０５Ａと、からなるものである。 FIG. 1 is a configuration diagram of a dry molded body serving as an outer mold. FIG. 2 is a configuration diagram of another dry molded body serving as an outer mold.
As shown in FIG. 1, the precision casting mold is a precision casting mold used for manufacturing a casting, and corresponds to the shape of the core corresponding to the hollow portion inside the casting and the shape of the outer peripheral surface of the casting. A casting slurry for precision casting made of ultra-fine alumina (Al 2 O 3 ) particles formed on the inner peripheral surface and having a particle size of 1.0 μm or less. A prime layer (first dry film) 101A made of a slurry film dried by using a slurry, and a slurry layer 102 made of the precision casting mold slurry and formed outside the prime layer (first dry film) 101A; A first backup layer (second dry film) 104-1 formed by a stucco layer 103 having a stucco material adhered to the slurry layer 102 and dried; It is made of.
　ここで、本発明でスラリーを形成するバインダである高純度超微粒のアルミナ微粒子（アルミナ超微粒子）は、分散手段である例えばボールミルを用いて、単一分散されているものを用いる。
　単一分散されているとは、例えば粒径が約０．５μｍのアルミナ微粒子を用いてスラリーを形成する場合、分散処理をした結果においても、０．５μｍに単一分散されている状態をいう。
　ここで、アルミナ微粒子の粒径としては、１．０μｍ以下、より好ましくは０．３～０．５μｍの範囲とするのが良い。 Here, the high-purity ultrafine alumina particles (alumina ultrafine particles), which are the binder for forming the slurry in the present invention, are monodispersed using, for example, a ball mill as a dispersing means.
The term “monodispersed” refers to a state in which, for example, when a slurry is formed using alumina fine particles having a particle diameter of about 0.5 μm, the result of the dispersion treatment is also monodispersed to 0.5 μm. .
Here, the particle diameter of the alumina fine particles is 1.0 μm or less, more preferably in the range of 0.3 to 0.5 μm.
　本発明では、アルミナ微粒子が１．０μｍ以下が好ましいのは、１．０μｍを超えると、曲げ試験強度の結果が好ましくないことによる。
　図３は、粒径と強度との関係を示す図である。
　図３に示すように、粒径が１．０μｍを超える場合、所望の強度を確保できず、好ましくないこととなる。 In the present invention, the reason why the alumina fine particles are preferably 1.0 μm or less is that if it exceeds 1.0 μm, the result of the bending test strength is not preferable.
FIG. 3 is a diagram showing the relationship between particle size and strength.
As shown in FIG. 3, when the particle diameter exceeds 1.0 μm, the desired strength cannot be ensured, which is not preferable.
　この単一分散されたアルミナ微粒子のバインダに、フラワーとして、ジルコン粉（例えば３５０メッシュ）を添加して精密鋳造用鋳型スラリーを得る。
　なお、本発明では、フラワーを添加しない場合も許容されうる。 Zircon powder (for example, 350 mesh) is added as flour to the single dispersed alumina fine particle binder to obtain a precision casting mold slurry.
In the present invention, it is acceptable to add no flour.
　ここで、単一分散させるための分散剤として、例えばポリカルボン酸塩（例えばアンモニウム塩）を用いて、分散させるようにしている。 Here, for example, polycarboxylate (for example, ammonium salt) is used as a dispersant for monodispersing, and the dispersion is performed.
　また、分散手段としては、例えば直径１０～２０ｍｍボールを用いたボールミルを例示することができるが、単一分散する手段であれば、これに限定されるものではない。 Further, as the dispersing means, for example, a ball mill using balls having a diameter of 10 to 20 mm can be exemplified, but the dispersing means is not limited to this as long as it is a single dispersing means.
　本発明では、バインダであるアルミナ微粒子を単一分散させた良好なスラリーとすることが肝要となる。
　図４は、アルミナ微粒子の粒度分布を示す図である。
　単一分散としては、粒径分布が狭いことが必要となり、図４に示すように、中心粒径（ｄ）から、０．８ｄ～１．２ｄの範囲に分布がおさまるような分散とするのが好ましい。 In the present invention, it is important to obtain a good slurry in which alumina fine particles as a binder are monodispersed.
FIG. 4 is a diagram showing the particle size distribution of alumina fine particles.
As the single dispersion, it is necessary that the particle size distribution is narrow, and as shown in FIG. 4, the dispersion is such that the distribution falls within the range of 0.8d to 1.2d from the center particle size (d). Is preferred.
　ここで、粒度分布の計測は、下記装置によった。
　株式会社アイシンナノテクノロジーズ製、「ＣＩＬＡＳ　８５０Ｂ型」のレーザー散乱・回折式粒度分布測定装置を用いた。 Here, the particle size distribution was measured by the following apparatus.
A laser scattering / diffraction type particle size distribution measuring device manufactured by Aisin Nano Technologies, Inc., “CILAS 850B type” was used.
　次に、精密鋳造用鋳型の製造方法を図１、図２により説明する。
（第１成膜工程）
　先ず、この第１成膜工程では、このアルミナ超微粒子からなる精密鋳造用鋳型スラリー（以下「スラリー」という）を用いて、ろう型３０を浸漬させ、引き上げ、余分なスラリーを落下させる。その後、乾燥させることで、ろう型３０表面に、スラリー膜（第１乾燥膜）を得る。
　このスラリー膜が、図１において、ろう型３０の表面と接するプライム層１０１Ａとなる。 Next, a method for manufacturing a precision casting mold will be described with reference to FIGS.
(First film formation step)
First, in the first film formation step, the mold 30 for precision casting (hereinafter referred to as “slurry”) made of ultrafine alumina particles is used to immerse the wax mold 30 and lift it to drop excess slurry. Thereafter, a slurry film (first dry film) is obtained on the surface of the wax mold 30 by drying.
This slurry film becomes a prime layer 101A in contact with the surface of the wax mold 30 in FIG.
（第２成膜工程）
　次いで、このプライム層１０１Ａを有するろう型３０を、スラリーに浸漬させた後、引上げ、余分なスラリーを落下させ、スラリー層（２層目）１０２を形成する。この濡れているスラリー層（２層目）１０２にスタッコ材としてジルコンスタッコ粒（平均粒径０．８ｍｍ）を振掛けて（スタッコイングして）、スタッコ材を付着させたスタッコ層（１層目）１０３を形成する。このスラリー層１０２とスタッコ層（１層目）１０３との積層体を乾燥して、プライム層（第１乾燥膜）１０１の上に第１バックアップ層（第２乾燥膜）１０４－１を形成する。 (Second film formation step)
Next, after the wax mold 30 having the prime layer 101A is immersed in the slurry, it is pulled up and the excess slurry is dropped to form the slurry layer (second layer) 102. The wet slurry layer (second layer) 102 is sprinkled (stuccoed) with zircon stucco grains (average particle size 0.8 mm) as a stucco material, and the stucco layer (first layer) is attached. ) 103 is formed. The laminate of the slurry layer 102 and the stucco layer (first layer) 103 is dried to form the first backup layer (second dry film) 104-1 on the prime layer (first dry film) 101. .
（成形体形成工程）
　この第１バックアップ層１０４－１の第２成膜工程と同様の操作を複数回（例えば６～１０回）繰り返し、スラリー層（ｎ＋１層目）１０２とスタッコ層（ｎ層目）１０３とが交互に積層された所定厚みの複層バックアップ層１０５Ａを有する外側鋳型となる乾燥成形体１０６Ａを得る。 (Molded body forming process)
The same operation as the second film forming step of the first backup layer 104-1 is repeated a plurality of times (for example, 6 to 10 times), and the slurry layer (n + 1 layer) 102 and the stucco layer (n layer) 103 are alternately arranged. A dry molded body 106A serving as an outer mold having a multilayer backup layer 105A having a predetermined thickness laminated on the substrate is obtained.
　この乾燥成形体を例えば１５０℃のオートクレーブに入れて、ろう型３０を構成するワックスを融解し、排出させる。
　その後、この型を１，０００℃で熱処理し、精密鋳造用鋳型を得る。 This dried molded body is put into an autoclave at 150 ° C., for example, and the wax constituting the wax mold 30 is melted and discharged.
Thereafter, this mold is heat-treated at 1,000 ° C. to obtain a precision casting mold.
　この得られた精密鋳造用鋳型は、後述する試験例に示すように、１５００℃の強度試験においても変形はなく、強度が高いものであった。これに対し、従来のシリカゾルを使用したものでは軟化の挙動が確認された。 The obtained mold for precision casting was high in strength without deformation in a 1500 ° C. strength test, as shown in a test example described later. On the other hand, the softening behavior was confirmed using the conventional silica sol.
　また、図２に示すように、プライム層において、プライムスラリー層１０１ａに、スタッコ材を付着させてプライムスタッコ層１０１ｂを形成し、その後乾燥して、プライム層１０１Ｂとするようにしても良い。
　なお、このプライム層１０１Ｂのように、スタッコ材を付着させた場合には、複層バックアップ層１０５Ｂのスラリー層の積層回数と、スタッコ層１０３の積層回数とは共に同数（ｎ層）からなる複層バックアップ層１０５Ｂを有する外側鋳型となる乾燥成形体１０６Ｂを得ることとなる。 Further, as shown in FIG. 2, in the prime layer, a stucco material may be attached to the prime slurry layer 101a to form the prime stucco layer 101b, and then dried to form the prime layer 101B.
When a stucco material is attached as in the prime layer 101B, the number of times that the slurry layer of the multilayer backup layer 105B is stacked and the number of times that the stucco layer 103 is stacked are the same number (n layers). A dry molded body 106B serving as an outer mold having the layer backup layer 105B is obtained.
　本発明では、フラワーとしてジルコン粉を用いたが、ジルコン粉以外に、アルミナ粉を用いると共に、スタッコ材としてジルコンスタッコ粒の代わりにアルミナスタッコ粒を用いても、同様な精密鋳造用鋳型を得ることができる。
　なお、フラワーとスタッコ材との関係は、限定されるものではなく、フラワーとしてジルコン粉、アルミナ粉のいずれかを用いると共に、スタッコ材として、ジルコンスタッコ粒、アルミナスタッコ粒のいずれかを用いるようにすれば良い。 In the present invention, zircon powder was used as the flour, but in addition to zircon powder, alumina powder was used, and even if alumina stucco particles were used instead of zircon stucco particles, the same precision casting mold was obtained. Can do.
The relationship between the flour and the stucco material is not limited, and either zircon powder or alumina powder is used as the flour, and either zircon stucco particle or alumina stucco particle is used as the stucco material. Just do it.
　このフラワーの粒径は、３５０メッシュとしているが、本発明ではこれに限定されず、例えば５～８０μｍ程度の粒子、平均粒径としては、例えば５０μｍ以下のものを使用することが好ましい。 The particle size of the flour is 350 mesh, but the present invention is not limited to this. For example, it is preferable to use particles having a size of about 5 to 80 μm and an average particle size of, for example, 50 μm or less.
　このスタッコ粒の粒径は、０．８ｍｍとしているが、本発明ではこれに限定されず、例えば０．４ｍｍ～２ｍｍ位の粒子、平均粒径としては例えば０．５ｍｍ以上のものを使用することが好ましい。 The stucco particles have a particle size of 0.8 mm, but the present invention is not limited to this. For example, particles having a diameter of about 0.4 mm to 2 mm and an average particle size of 0.5 mm or more should be used. Is preferred.
　以下、本発明の精密鋳造用鋳型を用いた鋳造方法について説明する。 Hereinafter, a casting method using the precision casting mold of the present invention will be described.
　図５は、鋳造方法の工程の一例を示すフローチャートである。以下、図５を用いて、鋳造方法について説明する。ここで、図５に示す処理は、全自動で実行しても良いし、オペレータが各工程を実行する装置を操作して実行しても良い。本実施形態の鋳造方法は、鋳型を作製する（ステップＳ１）。鋳型は、予め作製しておいても良いし、鋳造を実行する毎に作製しても良い。 FIG. 5 is a flowchart showing an example of the steps of the casting method. Hereinafter, the casting method will be described with reference to FIG. Here, the processing shown in FIG. 5 may be executed fully automatically, or may be executed by an operator operating an apparatus that executes each process. The casting method of this embodiment produces a casting mold (step S1). The mold may be produced in advance or may be produced each time casting is performed.
　以下、図６から図１２を用いて、ステップＳ１の工程で実行する本実施形態の鋳型製造方法について説明する。図６は、鋳型製造方法の工程の一例を示すフローチャートである。ここで、図６に示す処理は、全自動で実行しても良いし、オペレータが各工程を実行する装置を操作して実行しても良い。 Hereinafter, the mold manufacturing method of the present embodiment executed in the step S1 will be described with reference to FIGS. FIG. 6 is a flowchart showing an example of the steps of the mold manufacturing method. Here, the process shown in FIG. 6 may be executed fully automatically, or may be executed by an operator operating an apparatus that executes each process.
　鋳型製造方法は、コア（中子）を作製する（ステップＳ１２）。コアは、鋳型で作製する鋳物の内部の空洞に対応する形状である。つまり、コアは、鋳物の内部の空洞に対応する部分に配置されることで、鋳造時に鋳物となる金属が流れ込むことを抑制する。以下、図７を用いて、コアの製造工程について説明する。図７は、コアの製造工程を模式的に示す説明図である。鋳型製造方法は、図７に示すように金型１２を準備する（ステップＳ１０１）。金型１２は、コアに対応する領域が空洞となっている。コアの空洞となる部分が凸部１２ａとなる。なお、図７では、金型１２の断面で示しているが、金型１２は、空間に材料を注入する開口や空気を抜く穴以外は、基本的にコアに対応する領域の全周を覆う空洞となっている。鋳型鋳造方法は、矢印１４に示すようにセラミックスラリー１６を、金型１２の空間に材料を注入する開口から金型１２の内部に注入する。具体的には、セラミックスラリー１６を金型１２の内部に噴射する、いわゆる射出成形でコア１８を作製する。鋳型製造方法は、金型１２の内部にコア１８を作製したら、金型１２からコア１８を取り外し、取り外したコア１８を焼成炉２０に設置し、焼成させる。これにより、セラミックで形成されたコア１８を焼き固める（ステップＳ１０２）。鋳型鋳造方法は、以上のようにしてコア１８を作製する。なお、コア１８は、鋳物が固まった後に化学処理等の脱コア処理で取り除ける材料で形成される。 The mold manufacturing method produces a core (core) (step S12). A core is a shape corresponding to the cavity inside the casting produced with a casting_mold | template. That is, the core is arranged in a portion corresponding to the cavity inside the casting, thereby suppressing the metal that becomes the casting from flowing in at the time of casting. Hereinafter, the manufacturing process of the core will be described with reference to FIG. FIG. 7 is an explanatory view schematically showing a core manufacturing process. In the mold manufacturing method, a mold 12 is prepared as shown in FIG. 7 (step S101). The mold 12 has a hollow area corresponding to the core. The portion that becomes the cavity of the core becomes the convex portion 12a. In FIG. 7, the cross section of the mold 12 is shown. However, the mold 12 basically covers the entire circumference of the region corresponding to the core except for an opening for injecting material into the space and a hole for extracting air. It is hollow. In the mold casting method, the ceramic slurry 16 is injected into the mold 12 through an opening for injecting material into the space of the mold 12 as indicated by an arrow 14. Specifically, the core 18 is produced by so-called injection molding in which the ceramic slurry 16 is injected into the mold 12. In the mold manufacturing method, when the core 18 is produced inside the mold 12, the core 18 is removed from the mold 12, and the removed core 18 is placed in the firing furnace 20 and fired. Thereby, the core 18 made of ceramic is baked and hardened (step S102). In the mold casting method, the core 18 is produced as described above. The core 18 is formed of a material that can be removed by a decore process such as a chemical process after the casting is solidified.
　鋳型製造方法は、コア１８を作製したら、外部金型の作製を行う（ステップＳ１４）。外部金型は、内周面が鋳物の外周面に対応した形状となる。金型は、金属で形成しても良いし、セラミックで形成しても良い。図８は、金型の一部を模式的に示す斜視図である。図８に示す金型２２ａは、内周面に形成された凹部が鋳物の外周面に対応している。なお、図８では、金型２２ａのみを示したが、金型２２ａに対応し、内周面に形成された凹部を塞ぐ向きに金型２２ａに対応する金型も作製する。鋳型製造方法は、２つの金型を合わせることで、内周面が鋳物の外周面に対応した型となる。 In the mold manufacturing method, after the core 18 is manufactured, an external mold is manufactured (step S14). The outer mold has a shape in which the inner peripheral surface corresponds to the outer peripheral surface of the casting. The mold may be made of metal or ceramic. FIG. 8 is a perspective view schematically showing a part of the mold. As for the metal mold | die 22a shown in FIG. 8, the recessed part formed in the internal peripheral surface respond | corresponds to the outer peripheral surface of a casting. In FIG. 8, only the mold 22a is shown, but a mold corresponding to the mold 22a is also produced corresponding to the mold 22a so as to close the recess formed on the inner peripheral surface. In the mold manufacturing method, two molds are combined to form a mold whose inner peripheral surface corresponds to the outer peripheral surface of the casting.
　鋳型製造方法は、外部金型を作製したら、ろう型（ワックス型）の作製を行う（ステップＳ１６）。以下、図９を用いて説明する。図９は、ろう型の製造工程を模式的に示す説明図である。鋳型製造方法は、金型２２ａの所定位置にコア１８を設置する（ステップＳ１１０）。その後、金型２２ａに対応する金型２２ｂを、金型２２ａの凹部が形成されている面に被せ、コア１８の周囲を金型２２ａ、２２ｂで囲み、コア１８と金型２２ａ、２２ｂとの間に空間２４を形成する。鋳型製造方法は、矢印２６に示すように、空間２４と連結された配管から空間２４の内部に向けてＷＡＸ２８の注入を開始する（ステップＳ１１２）。ＷＡＸ２８は、所定の温度以上に加熱されると溶けるような、融点が比較的低温の物質、例えばろうである。鋳型製造方法は、空間２４の全域にＷＡＸ２８を充填させる（ステップＳ１１３）。その後、ＷＡＸ２８を固化させることで、コア１８の周囲をＷＡＸ２８が囲んだろう型３０を形成する。ろう型３０は、基本的にＷＡＸ２８で形成される部分が製造する目的の鋳物と同じ形状となる。その後、鋳物製造方法は、ろう型３０を金型２２ａ、２２ｂから分離し、湯口３２を取り付ける（ステップＳ１１４）。湯口３２は、鋳造時に溶けた金属である溶湯が投入される口である。鋳型製造方法は、以上のようにして、内部にコア１８を含み、鋳物と同一の形状のＷＡＸ２８で形成されたろう型３０を作製する。 In the mold manufacturing method, when an external mold is manufactured, a wax mold is manufactured (step S16). Hereinafter, a description will be given with reference to FIG. FIG. 9 is an explanatory view schematically showing a wax mold manufacturing process. In the mold manufacturing method, the core 18 is installed at a predetermined position of the mold 22a (step S110). Thereafter, a mold 22b corresponding to the mold 22a is placed on the surface of the mold 22a where the recess is formed, the core 18 is surrounded by the molds 22a and 22b, and the core 18 and the molds 22a and 22b are separated. A space 24 is formed therebetween. The mold manufacturing method starts injection of WAX 28 from the pipe connected to the space 24 toward the inside of the space 24 as indicated by an arrow 26 (step S112). WAX 28 is a substance having a relatively low melting point, such as wax, which melts when heated above a predetermined temperature. In the mold manufacturing method, the entire space 24 is filled with the WAX 28 (step S113). Thereafter, the wax 28 is solidified to form the wax mold 30 in which the WAX 28 surrounds the core 18. The wax mold 30 basically has the same shape as the casting for which the part formed by the WAX 28 is manufactured. Thereafter, in the casting manufacturing method, the wax mold 30 is separated from the molds 22a and 22b, and the gate 32 is attached (step S114). The gate 32 is a port into which molten metal, which is a metal melted during casting, is charged. As described above, the mold manufacturing method produces the wax mold 30 including the core 18 inside and formed of the WAX 28 having the same shape as the casting.
　鋳型製造方法は、ろう型３０を作製したら、スラリー塗布（ディッピング）を行う（ステップＳ１８）。図１０は、ろう型にスラリーを塗布する構成を模式的に示す説明図である。鋳型製造方法は、図１０に示すように、スラリー４０が貯留された貯留部４１にろう型３０を浸漬させ、取り出した後、乾燥を行う（ステップＳ１９）。これにより、ろう型３０の表面にプライム層１０１Ａを形成することができる。
　ここで、ステップＳ１８で塗布するスラリーは、ろう型３０に直接塗布されるスラリーである。このスラリー４０は、アルミナ超微粒子が単一分散されたスラリーを用いる。このスラリー４０には、フラワーとして３５０メッシュ程度の耐火性の微粒子、例えばジルコニアを用いることが好ましい。また、分散剤としてポリカルボン酸塩を用いることが好ましい。また、スラリー４０には、消泡剤（シリコン系の物質）や、濡れ性改善剤を微量、例えば０．０１％添加することが好ましい。濡れ性改善剤を添加することで、スラリー４０のろう型３０への付着性を向上させることができる。 In the mold manufacturing method, when the wax mold 30 is produced, slurry application (dipping) is performed (step S18). FIG. 10 is an explanatory diagram schematically showing a configuration in which slurry is applied to a wax mold. In the mold manufacturing method, as shown in FIG. 10, the wax mold 30 is immersed in the storage part 41 in which the slurry 40 is stored, and is taken out and then dried (step S19). Thereby, the prime layer 101 </ b> A can be formed on the surface of the wax mold 30.
Here, the slurry applied in step S <b> 18 is a slurry applied directly to the wax mold 30. As the slurry 40, a slurry in which alumina ultrafine particles are monodispersed is used. In the slurry 40, it is preferable to use refractory fine particles of about 350 mesh, such as zirconia, as flour. Moreover, it is preferable to use polycarboxylate as a dispersing agent. Further, it is preferable to add a small amount, for example, 0.01%, of an antifoaming agent (silicon-based substance) or a wettability improving agent to the slurry 40. By adding the wettability improving agent, the adhesion of the slurry 40 to the wax mold 30 can be improved.
　鋳型製造方法は、図１０に示すように、スラリー４０でスラリー塗布を行って、乾燥しプライム層（第１乾燥膜）１０１Ａを有するろう型を、さらにスラリー塗布（ディッピング）を行う（ステップＳ２０）。図１１に示すように、この濡れているスラリーの表面にスタッコ材５４としてジルコンスタッコ粒（平均粒径０．８ｍｍ）を振掛けるスタッコイングを行う（ステップＳ２１）。その後スラリー層の表面にスタッコ材が付着されたものを乾燥し、プライム層（第１乾燥膜）１０１Ａの上に第１バックアップ層（第２乾燥膜）１０４－１を形成した（ステップＳ２２）。
　この第１バックアップ層（第２乾燥膜）１０４－１の形成工程と同様の操作を複数回（例えばｎ：６～１０回）繰り返す判断を行う（ステップＳ２３）。所定回数（ｎ）の第ｎバックアップ層１０４－ｎを積層させ（ステップＳ２３：Ｙｅｓ）、複層バックアップ層１０５Ａが形成された厚みが例えば１０ｍｍの外側鋳型となる乾燥成形体１０６Ａを得る。 In the mold manufacturing method, as shown in FIG. 10, slurry application is performed with the slurry 40, and then the solder mold having the prime layer (first dry film) 101A is further applied with slurry (dipping) (step S20). . As shown in FIG. 11, stuccoing is performed by sprinkling zircon stucco grains (average particle size 0.8 mm) as the stucco material 54 on the surface of the wet slurry (step S21). Thereafter, the slurry layer with the stucco material attached thereto was dried to form the first backup layer (second dry film) 104-1 on the prime layer (first dry film) 101A (step S22).
A determination is made to repeat the same operation as that for forming the first backup layer (second dry film) 104-1 a plurality of times (for example, n: 6 to 10 times) (step S23). A predetermined number (n) of n-th backup layers 104-n are stacked (step S23: Yes) to obtain a dry molded body 106A that is an outer mold having a thickness of, for example, 10 mm on which the multilayer backup layer 105A is formed.
　鋳型製造方法は、プライム層１０１Ａと複層バックアップ層１０５Ａの複数層が形成された乾燥成形体１０６Ａを得たら、当該乾燥成形体１０６Ａに対して熱処理を行う（ステップＳ２４）。具体的には、外側鋳型とコアとの間にあるＷＡＸを除去し、さらに外側鋳型とコアとを焼成させる。以下、図１２を用いて説明する。図１２は、鋳型製造方法の一部工程を模式的に示す説明図である。鋳型製造方法は、ステップＳ１３０に示すように、プライム層１０１Ａと複層バックアップ層１０５Ａの複数層が形成された外側鋳型となる乾燥成形体１０６Ａをオートクレーブ６０の内部に入れ、加熱する。オートクレーブ６０は、内部を加圧蒸気で満たすことで、乾燥成形体１０６Ａ内のろう型３０を加熱する。これにより、ろう型３０を構成するＷＡＸが溶け、溶融ＷＡＸ６２が乾燥成形体１０６Ａで囲まれた空間６４から排出される。
　鋳型製造方法は、溶けたＷＡＸ６２を空間６４から排出することで、ステップＳ１３１に示すように、外側鋳型となる乾燥成形体１０６Ａと、コア１８との間のＷＡＸが充填されていた領域に空間６４が形成された鋳型７２が作製される。その後、鋳型製造方法は、ステップＳ１３２に示すように、外側鋳型となる乾燥成形体１０６Ａとコア１８との間に空間６４が形成された鋳型７２を、焼成炉７０で加熱する。これにより、鋳型７２は、外側鋳型となる乾燥成形体１０６Ａに含まれる水成分や不要な成分が除去され、さらに、焼成されることで硬化され、外側鋳型６１が形成される。鋳物製造方法は、以上のようにして鋳型７２を作製する。 In the mold manufacturing method, after obtaining the dry molded body 106A on which a plurality of layers of the prime layer 101A and the multilayer backup layer 105A are obtained, the dry molded body 106A is subjected to heat treatment (step S24). Specifically, WAX between the outer mold and the core is removed, and the outer mold and the core are further fired. Hereinafter, a description will be given with reference to FIG. FIG. 12 is an explanatory view schematically showing a part of the mold manufacturing method. In the mold manufacturing method, as shown in step S130, a dry molded body 106A serving as an outer mold in which a plurality of layers of the prime layer 101A and the multilayer backup layer 105A is formed is placed in the autoclave 60 and heated. The autoclave 60 heats the wax mold 30 in the dry molded body 106A by filling the interior with pressurized steam. As a result, the WAX constituting the wax mold 30 is melted, and the molten WAX 62 is discharged from the space 64 surrounded by the dry molded body 106A.
In the mold manufacturing method, the melted WAX 62 is discharged from the space 64, so that, as shown in step S131, an area filled with WAX between the dry molded body 106A serving as the outer mold and the core 18 is filled with the space 64. A mold 72 in which is formed is produced. Thereafter, in the mold manufacturing method, as shown in step S132, the mold 72 in which the space 64 is formed between the dry molded body 106A serving as the outer mold and the core 18 is heated in the firing furnace 70. As a result, the mold 72 removes the water component and unnecessary components contained in the dry molded body 106 </ b> A serving as the outer mold, and is further cured by firing to form the outer mold 61. In the casting manufacturing method, the mold 72 is produced as described above.
　図５と図１３を用いて、鋳造方法の説明を続ける。図１３は、鋳造方法の一部工程を模式的に示す説明図である。鋳造方法は、ステップＳ１で鋳型を作製したら、鋳型の予熱を行う（ステップＳ２）。例えば、鋳型７２を炉（真空炉、焼成炉）内に配置し、８００℃以上９００℃以下まで加熱する。予熱を行うことで、鋳物の製造時に鋳型に溶湯（溶けた金属）を注入した際に鋳型が損傷することを抑制することができる。 The explanation of the casting method will be continued using FIG. 5 and FIG. FIG. 13 is an explanatory view schematically showing a part of the casting method. In the casting method, when the mold is produced in step S1, the mold is preheated (step S2). For example, the mold 72 is placed in a furnace (vacuum furnace, firing furnace) and heated to 800 ° C. or higher and 900 ° C. or lower. By performing preheating, it is possible to prevent the mold from being damaged when molten metal (melted metal) is injected into the mold at the time of casting production.
　鋳造方法は、鋳型を予熱したら、注湯を行う（ステップＳ３）。つまり、図１３のステップＳ１４０に示すように、溶湯８０、つまり溶解した鋳物の原料（例えば鋼）を鋳型７２の開口から外側鋳型６１とコア１８との間に注入する。 In the casting method, when the mold is preheated, pouring is performed (step S3). That is, as shown in step S <b> 140 of FIG. 13, molten metal 80, that is, a molten casting material (for example, steel) is injected between the outer mold 61 and the core 18 from the opening of the mold 72.
　鋳造方法は、鋳型７２に注いだ溶湯８０を固化させたら、外側鋳型６１を除去する（ステップＳ４）。つまり、図１３のステップＳ１４１に示すように、鋳型７２の内部で溶湯８０が固まって鋳物９０となったら、外側鋳型６１を粉砕して破片６１ａとして、鋳物９０から取り外す。 In the casting method, after the molten metal 80 poured into the mold 72 is solidified, the outer mold 61 is removed (step S4). That is, as shown in step S141 in FIG. 13, when the molten metal 80 is solidified into the casting 90 inside the mold 72, the outer mold 61 is crushed and removed from the casting 90 as broken pieces 61a.
　鋳造方法は、外側鋳型６１を鋳物９０から除去したら、脱コア処理を行う（ステップＳ５）。つまり、図１３のステップＳ１４２に示すように、オートクレーブ９２の内部に鋳物９０を入れ、脱コア処理を行うことで、鋳物９０の内部のコア１８を溶解し、溶解した溶解コア９４を鋳物９０の内部から排出する。具体的にはオートクレーブ９２の内部で鋳物９０をアルカリ溶液に投入し、加圧、減圧を繰り返すことで、鋳物９０から溶解コア９４を排出する。 In the casting method, when the outer mold 61 is removed from the casting 90, the core removal process is performed (step S5). That is, as shown in step S142 of FIG. 13, the casting 90 is put into the autoclave 92 and the core removal process is performed by melting the core 18 inside the casting 90, and the melted melting core 94 is converted into the casting 90 of the casting 90. Drain from inside. Specifically, the casting 90 is put into an alkaline solution inside the autoclave 92, and the melting core 94 is discharged from the casting 90 by repeating pressurization and decompression.
　鋳造方法は、脱コア処理を行ったら、仕上げ処理を行う（ステップＳ６）。つまり、鋳物９０の表面や内部に仕上げ処理を行う。また、鋳造方法では、仕上げ処理と共に鋳物の検品を行う。これにより、図１３のステップＳ１４３に示すように、鋳物１００を製造することができる。 As for the casting method, after the de-core process is performed, a finishing process is performed (step S6). That is, a finishing process is performed on the surface and inside of the casting 90. In the casting method, the casting is inspected together with the finishing process. Thereby, as shown to step S143 of FIG. 13, the casting 100 can be manufactured.
　本実施形態の鋳造方法は、以上のように、ＷＡＸ（ワックス）を用いたロストワックス鋳造法を用いて鋳型を作製し、鋳物を作製する。ここで、本実施形態の鋳型製造方法、鋳造方法及び鋳型は、鋳型の外側の部分である外側鋳型を、スラリーとしてアルミナ超微粒子を用いて内周面となるプライム層（初層である第１乾燥膜）１０１Ａを形成し、このプライム層１０１Ａの外部に複数層のバックアップ層１０５Ａを形成しての多層構造としている。
　なお、前述したように、プライム層として、スタッコ材を添加したスラリー層１０１ａとスタッコ層１０１ｂとからなるプライム層１０１Ｂとしてもよい（図２参照）。 As described above, in the casting method of the present embodiment, a casting mold is manufactured by using a lost wax casting method using WAX (wax). Here, the mold manufacturing method, the casting method, and the mold according to the present embodiment include an outer mold that is an outer portion of the mold, and a prime layer (first layer that is the first layer) that forms an inner peripheral surface using alumina ultrafine particles as a slurry. (Dry film) 101A is formed, and a plurality of backup layers 105A are formed outside the prime layer 101A to form a multilayer structure.
As described above, the prime layer 101B including the slurry layer 101a to which the stucco material is added and the stucco layer 101b may be used as the prime layer (see FIG. 2).
　（実施例１）
　以下、実施例を用いて、本実施形態の鋳型製造方法及び鋳造方法について説明する。なお、以下の実施例では、外側鋳型が形成される前のろう型を幅３０ｍｍ、厚さ８ｍｍ、長さ３００ｍｍの部材とし、このろう型にスラリー層からなるプライム層（第１乾燥膜）、スラリーとスタッコ材による複層のバックアップ層を形成して鋳型を作製した。 (Example 1)
Hereinafter, the mold manufacturing method and the casting method of the present embodiment will be described using examples. In the following examples, the wax mold before the outer mold is formed is a member having a width of 30 mm, a thickness of 8 mm, and a length of 300 mm, and this wax mold has a prime layer (first dry film) made of a slurry layer, A mold was prepared by forming a multilayer backup layer of slurry and stucco material.
　高純度超微粒のアルミナ（Ａｌ2Ｏ3、比表面積１０ｍ2／ｇ、粒径約０．５μｍ）のスラリーを、分散剤としてポリカルボン酸塩を用い、ボールミルを用いて２４時間混練してスラリー化し、アルミナスラリーを得た。得られたアルミナスラリーの固形分濃度は５０ｗｔ％である。
　このアルミナスラリーでは、分散処理の結果アルミナ粒子は０．５μｍに単一分散されていることが確認された。
　このアルミナスラリーに、フラワーとして３５０メッシュのジルコン粉を添加して、精密鋳造用鋳型スラリーとした。
　また、同時に、消泡剤としてシリコン系のものを０．０１％、濡れ性改善剤を０．０１％添加して、使用スラリーとした。 A slurry of high-purity ultrafine alumina (Al 2 O 3 , specific surface area 10 m 2 / g, particle size of about 0.5 μm) is kneaded for 24 hours using a polycarboxylate as a dispersant and using a ball mill. An alumina slurry was obtained. The solid content concentration of the obtained alumina slurry is 50 wt%.
In this alumina slurry, as a result of the dispersion treatment, it was confirmed that the alumina particles were monodispersed to 0.5 μm.
To this alumina slurry, 350 mesh zircon powder was added as flour to prepare a precision casting mold slurry.
At the same time, 0.01% silicon-based antifoaming agent and 0.01% wettability improving agent were added to prepare slurry for use.
　幅３０ｍｍ、厚さ８ｍｍ、長さ３００ｍｍのワックス体を準備し、得られた使用スラリーにワックス体を浸漬し、引き上げてワックス表面に使用スラリーを付着させた後、余分な使用スラリーを落下させ、乾燥することによりワックス体の表面にスラリーのプライム層（第１乾燥膜）を得た。 Prepare a wax body with a width of 30 mm, a thickness of 8 mm, and a length of 300 mm, immerse the wax body in the obtained use slurry, pull it up and attach the use slurry to the wax surface, then drop the excess use slurry, By drying, a slurry prime layer (first dry film) was obtained on the surface of the wax body.
　次に、第２乾燥膜を得るため、プライム層を有するワックス体を使用スラリーに浸漬した後、引き上げ余分な使用スラリーを落下させた。
　濡れているスラリーに、平均粒系０．８ｍｍのジルコンスタッコ粒を付着させた後乾燥し、第２乾燥膜（第１バックアップ層）を形成した。 Next, in order to obtain the second dry film, the wax body having the prime layer was immersed in the use slurry, and then the excess use slurry was dropped.
Zircon stucco grains having an average grain size of 0.8 mm were adhered to the wet slurry and then dried to form a second dry film (first backup layer).
　この第２乾燥膜（第１バックアップ層）の形成と同等の操作を６回繰り返して複層のバックアップ層を有する、厚み約１０ｍｍの成形体を得た。
　この得られた乾燥成形体を１５０℃のオートクレーブに入れて、ワックスを融解し、排出した。
　次いで、この型を１０００℃で熱処理し、実施例１の鋳型を得た。 An operation equivalent to the formation of the second dry film (first backup layer) was repeated 6 times to obtain a molded body having a thickness of about 10 mm having a multilayer backup layer.
The obtained dried molded body was put in an autoclave at 150 ° C. to melt and discharge the wax.
Next, this mold was heat-treated at 1000 ° C. to obtain a mold of Example 1.
［比較例］
　比較のため、従来と同様のシリカゾル（粒径２０ｎｍ程度の球状シリカ粒子が分散された液）を使用したスラリーを用い、実施例と同様の操作を行い比較例の鋳型も同時に試作した。 [Comparative example]
For comparison, a slurry using a conventional silica sol (a liquid in which spherical silica particles having a particle diameter of about 20 nm are dispersed) was used, and the same procedure as in the example was performed, and a template of a comparative example was also prototyped.
［試験］
　得られた実施例１の鋳型及び比較例の鋳型から、１０ｍｍ×５０ｍｍ、厚さ５ｍｍの強度試験片を加工し、高温強度試験を実施した。
　１５００℃の強度試験では、従来のシリカゾルを使用したものでは軟化の挙動が確認された。
　また、その結果、比較例の試験片の切断は明瞭でなく、曲がってしまった。
　これに対し、本実施例のアルミナスラリー（スタッコ材としてジルコン粒）を使用した試験片は変形もなく、１００ＭＰａでの破断であった。
　ここで、強度試験は、ＪＩＳ　Ｒ　１６０１による「セラミックスの曲げ強さ（１９８１）」に準拠しておこなった。 [test]
A strength test piece of 10 mm × 50 mm and a thickness of 5 mm was processed from the obtained mold of Example 1 and the comparative mold, and a high-temperature strength test was performed.
In the strength test at 1500 ° C., the softening behavior was confirmed using the conventional silica sol.
As a result, the test piece of the comparative example was not clearly cut and bent.
On the other hand, the test piece using the alumina slurry of this example (zircon grains as the stucco material) was not deformed and was broken at 100 MPa.
Here, the strength test was performed according to “Bending strength of ceramics (1981)” according to JIS R 1601.
　本試験結果より、バインダを、耐熱性が高い超微粒子アルミナ（融点２，０７０℃）のスラリーとし、スタッコ材をジルコン粒（融点２，７１５℃）とすることで、従来のシリカゾル使用に対して耐熱温度が向上し、一方向凝固翼製造における高温（１，５５０℃）で長時間保持した場合でも変形が生じない鋳型が得ることができた。 From this test result, the binder is a slurry of ultrafine alumina with a high heat resistance (melting point 2,070 ° C.) and the stucco material is a zircon grain (melting point 2,715 ° C.), so that the conventional silica sol is used. The heat-resistant temperature was improved, and a mold that did not deform even when kept at a high temperature (1,550 ° C.) for a long time in the production of a unidirectionally solidified blade could be obtained.
　（実施例２）
　実施例１において、フラワーとして、ジルコン粉の代わりに、３５０メッシュのアルミナ粉を添加して、精密鋳造用鋳型スラリーとした。
　また、スタッコ材として、平均粒径０．８ｍｍのアルミナスタッコ粒を用いた以外は、実施例１と同様に操作して、実施例２の鋳型を得た。 (Example 2)
In Example 1, 350 mesh alumina powder was added as flour instead of zircon powder to obtain a precision casting mold slurry.
Further, a mold of Example 2 was obtained in the same manner as in Example 1 except that alumina stucco particles having an average particle diameter of 0.8 mm were used as the stucco material.
［試験］
　得られた実施例２の鋳型及び比較例の鋳型から、１０ｍｍ×５０ｍｍ、厚さ５ｍｍの強度試験片を加工し、実施例１と同様の高温強度試験を実施した。
　本実施例のアルミナスラリー（スタッコ材としてアルミナ粒）を使用した試験片は変形もなく、１００ＭＰａでの破断であった。 [test]
A strength test piece of 10 mm × 50 mm and a thickness of 5 mm was processed from the obtained mold of Example 2 and the mold of Comparative Example, and the same high-temperature strength test as in Example 1 was performed.
The test piece using the alumina slurry of this example (alumina particles as the stucco material) was not deformed and was broken at 100 MPa.
　本試験結果より、バインダを、耐熱性が高い超微粒子アルミナ（融点２，０７０℃）のスラリーとし、スタッコ材をアルミナ粒（融点２，０７０℃）とすることで、従来のシリカゾル使用に対して耐熱温度が向上し、一方向凝固翼製造における高温（１，５５０℃）長時間保持でも変形が生じない鋳型が得られることができた。 From this test result, the binder was made into a slurry of ultrafine alumina (melting point 2,070 ° C.) with high heat resistance, and the stucco material was made into alumina particles (melting point 2,070 ° C.). The heat-resistant temperature was improved, and a mold that could not be deformed even when kept at a high temperature (1,550 ° C.) for a long time in the production of a unidirectionally solidified blade could be obtained.
　以上より、バインダを、耐熱性が高いアルミナ超微粒子スラリーの単一分散物をスラリーとし、ジルコン粉またはアルミナ粉のスタッコ材とすることで、従来のシリカゾルを使用した場合よりも、得られた鋳型の耐熱温度が向上し、一方向凝固翼製造における高温（１，５５０℃）で長時間保持した場合でも変形が生じない鋳型が得ることができた。 From the above, by using a binder, a single dispersion of highly heat-resistant alumina ultrafine particle slurry as a slurry, and using a stucco material of zircon powder or alumina powder, the obtained mold can be obtained as compared with the case where a conventional silica sol is used. The heat resistant temperature of the unidirectional solidified blade was improved, and a mold that did not deform even when kept at a high temperature (1,550 ° C.) for a long time in the production of a unidirectionally solidified blade could be obtained.
　１２、２２ａ、２２ｂ　金型
　１２ａ　凸部
　１４、２６　矢印
　１６　セラミックスラリー
　１８　コア（中子）
　２０、７０　焼成炉
　２４、６４　空間
　２８　ＷＡＸ（ろう）
　３０　ろう型
　３２　湯口
　４０　スラリー
　６０、９２　オートクレーブ
　６１　外側鋳型
　６１ａ　破片
　６２　溶融ＷＡＸ
　７２　鋳型
　８０　溶湯
　９０、１００　鋳物
　９４　溶解コア
　１０１Ａ、１０１Ｂ　プライム層
　１０２　スラリー層
　１０３　スタッコ層
　１０４－１　第１バックアップ層
　１０４－ｎ　第ｎバックアップ層
　１０５Ａ、１０５Ｂ　複層バックアップ層 12, 22a, 22b Mold 12a Convex 14, 26 Arrow 16 Ceramic slurry 18 Core (core)
20, 70 Firing furnace 24, 64 Space 28 WAX
30 Wax mold 32 Gate 40 Slurry 60, 92 Autoclave 61 Outer mold 61a Debris 62 Molten WAX
72 Mold 80 Melt 90, 100 Casting 94 Melting core 101A, 101B Prime layer 102 Slurry layer 103 Stucco layer 104-1 First backup layer 104-n nth backup layer 105A, 105B Multi-layer backup layer

Claims (6)

  1. 　鋳物の製造に用いる精密鋳造用鋳型であって、
    　前記鋳物の内部の空洞部分に対応する形状のコアと、
    　前記鋳物の外周面の形状に対応する外側鋳型と、を有し、
    　前記外側鋳型は、内周面に形成され、粒径１．０μｍ以下の単一分散してなるアルミナ超微粒子からなる精密鋳造用鋳型スラリーを用いて乾燥してなるスラリー膜からなるプライム層と、
    　前記プライム層の外側に形成され、前記精密鋳造用鋳型スラリーからなるスラリー層と、該スラリー層にスタッコ材を付着したスタッコ層とにより形成し、乾燥してなるバックアップ層を、複数回形成してなる複層バックアップ層と、からなることを特徴とする精密鋳造用鋳型。     A mold for precision casting used in the manufacture of castings,
    A core having a shape corresponding to a hollow portion inside the casting,
    An outer mold corresponding to the shape of the outer peripheral surface of the casting,
    The outer mold is formed on the inner peripheral surface, a prime layer made of a slurry film formed by drying using a precision casting mold slurry made of alumina ultrafine particles having a particle size of 1.0 μm or less, and
    A backup layer formed by drying a slurry layer formed of the precision casting mold slurry and a stucco layer having a stucco material attached to the slurry layer and dried, is formed a plurality of times. A precision casting mold comprising: a multilayer backup layer.
  2. 　請求項１において、
    　前記精密鋳造用鋳型スラリーに平均粒径が５０μｍ以下のジルコン粉、アルミナ粉をいずれか一方を含み、
    　前記スタッコ材が、平均粒径が０．５ｍｍ以上のジルコンスタッコ粒、アルミナスタッコ粒のいずれか一方であることを特徴とする精密鋳造用鋳型。     In claim 1,
    The precision casting mold slurry contains either one of zircon powder and alumina powder having an average particle size of 50 μm or less,
    The precision casting mold, wherein the stucco material is any one of zircon stucco grains having an average particle diameter of 0.5 mm or more and alumina stucco grains.
  3. 　請求項１又は２において、
    　前記プライム層が、精密鋳造用鋳型スラリーからなるスラリー層に、スタッコ材を付着したスタッコ層を有することを特徴とする精密鋳造用鋳型。     In claim 1 or 2,
    The precision casting mold, wherein the prime layer has a stucco layer in which a stucco material is attached to a slurry layer made of a precision casting mold slurry.
  4. 　鋳物の製造に用いる精密鋳造用鋳型の製造方法であって、
    　精密鋳造用ろう型を、粒径１．０μｍ以下の単一分散してなるアルミナ超微粒子からなる精密鋳造用鋳型スラリーに浸漬し、引き上げた後乾燥して、ろう型の表面にスラリー膜からなるプライム層を形成する第１成膜工程と、
    　前記プライム層を形成したろう型を、前記精密鋳造用鋳型スラリーに浸漬し、引き上げた後、スラリー表面にスタッコ材を振掛け、その後乾燥してバックアップ層を形成する第２成膜工程と、
    　前記第２成膜工程のバックアップ層を形成する工程を複数回繰り返し、複層バックアップ層を形成した成形体を得る成形体形成工程と、
    　得られた成形体からろう型のワックスを融解・除去する脱ワックス工程と、
    　脱ワックス後の成形体を焼成処理し、鋳型を得る鋳型焼成工程と、を有することを特徴とする精密鋳造用鋳型の製造方法。     A method for manufacturing a precision casting mold used for manufacturing a casting,
    The precision casting wax mold is immersed in a precision casting mold slurry made of ultra-fine alumina particles having a particle size of 1.0 μm or less, pulled up, and then dried to form a slurry film on the surface of the wax mold. A first film forming step for forming a prime layer;
    A second film forming step in which the wax mold in which the prime layer is formed is dipped in the precision casting mold slurry, pulled up, sprinkled with a stucco material on the slurry surface, and then dried to form a backup layer;
    The step of forming the backup layer of the second film formation step is repeated a plurality of times, and a molded body forming step for obtaining a molded body in which the multilayer backup layer is formed,
    A dewaxing step of melting and removing wax-type wax from the obtained molded body,
    And a mold firing step of firing the dewaxed molded body to obtain a mold, and a method for producing a precision casting mold.
  5. 　請求項４において、
    　前記第１成膜工程の際、前記精密鋳造用鋳型スラリーからなるスラリー層に、スタッコ材を付着してスタッコ層を形成し、その後乾燥することを特徴とする精密鋳造用鋳型の製造方法。     In claim 4,
    A method for producing a precision casting mold, wherein a stucco layer is formed by adhering a stucco material to a slurry layer made of the precision casting mold slurry during the first film forming step, followed by drying.
  6. 　請求項４又は５において、
    　前記精密鋳造用鋳型スラリーの分散剤がポリカルボン酸塩であることを特徴とする精密鋳造用鋳型の製造方法。     In claim 4 or 5,
    A precision casting mold manufacturing method, wherein the precision casting mold slurry dispersant is a polycarboxylate.
PCT/JP2013/077218 2012-10-09 2013-10-07 Mold for precision casting, and method for producing same WO2014057903A1 (en)

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JP2014076456A (en) 2014-05-01
US20150283601A1 (en) 2015-10-08

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