WO2024079946A1 - Cast shaping method and cast material - Google Patents

Cast shaping method and cast material Download PDF

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Publication number
WO2024079946A1
WO2024079946A1 PCT/JP2023/023577 JP2023023577W WO2024079946A1 WO 2024079946 A1 WO2024079946 A1 WO 2024079946A1 JP 2023023577 W JP2023023577 W JP 2023023577W WO 2024079946 A1 WO2024079946 A1 WO 2024079946A1
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Prior art keywords
mold
sand
binder
weight
aggregate
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PCT/JP2023/023577
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French (fr)
Japanese (ja)
Inventor
知裕 青木
哲司 松井
敏彦 善甫
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新東工業株式会社
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Publication of WO2024079946A1 publication Critical patent/WO2024079946A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
    • B22C1/10—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives for influencing the hardening tendency of the mould material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/18—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of inorganic agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/12—Treating moulds or cores, e.g. drying, hardening

Definitions

  • This disclosure relates to a mold making method and mold material.
  • Patent Document 1 discloses a mold.
  • the mold is produced by binding molded silica sand with a binder.
  • the main component of silica sand is silicon dioxide (SiO 2 ).
  • metal oxides e.g., FeO
  • SiO 2 silicon dioxide
  • Fayalite (2FeO.SiO 2 ) may cause seizure defects on the surface of the casting or cause insertion failure.
  • it is possible to apply a mold coat to the mold In order to reduce the defects, for example, it is possible to apply a mold coat to the mold. However, this increases the number of manufacturing steps, which reduces productivity.
  • the present disclosure provides a technique for suppressing the occurrence of defects without reducing productivity in the molding of molds for manufacturing iron-based castings.
  • a method for making a mold for producing a ferrous casting includes the following steps: (1) A step of producing mixed sand using artificial sand as aggregate and a binder; (2) A step of filling the mixed sand into a mold; and (3) A step of solidifying the mixed sand filled into the mold.
  • the artificial sand contains 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ), and the binder may be either sodium silicate or potassium silicate.
  • the binder may have a molar ratio of 1.8 or more.
  • the mold making method can improve the collapse property of the mold while maintaining the strength of the mold.
  • the binder may be 4 parts by weight or less per 100 parts by weight of aggregate.
  • natural silica sand is used as the aggregate, generally more than 4 parts by weight of binder is added.
  • this mold making method by using artificial sand as the aggregate, it is possible to obtain sufficient strength of the mold even if the amount of binder added is 4 parts by weight or less. Therefore, this mold making method can improve the collapseability of the mold while maintaining the strength of the mold.
  • the artificial sand may be produced by a melting or sintering process.
  • This mold-making method can reduce production costs because artificial sand produced by the melting or sintering process can require less binder than artificial sand produced by other methods.
  • the solidification step may involve solidifying the mixed sand through a dehydration condensation reaction.
  • the filling step may involve blow-filling wet mixed sand into a heated mold, or injecting foamed mixed sand into the mold. This mold-making method allows for the creation of environmentally friendly foundries with little odor.
  • solidification is performed using an ester, an odor specific to organic matter is generated, and when solidification is performed by reacting metal powder with water glass, hydrogen is generated.
  • the solidifying step may solidify the mixed sand using carbon dioxide (CO 2 ) gas.
  • CO 2 carbon dioxide
  • the wet mixed sand can be filled by hand filling, vibration filling, squeezing, or blow filling in the filling step.
  • This mold making method can realize a foundry with less odor and a good environment.
  • ester an odor specific to organic matter is generated, and when solidifying by reacting metal powder with water glass, hydrogen is generated.
  • the mixed sand may be expanded mixed sand containing a surfactant.
  • this mold making method can improve the filling properties of the sand while suppressing the occurrence of defects without reducing productivity.
  • a mold material according to another aspect of the present disclosure is a material for a mold for producing an iron-based casting.
  • the mold material contains artificial sand containing 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ) as an aggregate, and either one of sodium silicate or potassium silicate as a binder.
  • This mold material contains 40% or less silicon dioxide (SiO 2 ) as an aggregate, and the content of silicon dioxide (SiO 2 ) is significantly reduced compared to natural silica sand containing 90% or more silicon dioxide (SiO 2 ).
  • a mold produced using this mold material is less likely to generate fayalite (2FeO.SiO 2 ) compared to a mold produced using natural silica sand as an aggregate. Therefore, this mold material can suppress the occurrence of seizure defects and insertion failures on the surface of the casting compared to a case in which natural silica sand is used as an aggregate. Furthermore, since fayalite (2FeO.SiO 2 ) is unlikely to be generated, there is no need to apply a mold coat, and therefore this mold material can suppress the occurrence of defects without reducing productivity.
  • This disclosure provides a technology that can reduce the occurrence of defects in the molding of molds for producing iron-based castings without reducing productivity.
  • 1 is a flowchart of a mold making method according to one embodiment.
  • 1 is a graph showing the relationship between the amount of binder added and bending strength for each aggregate.
  • 1 is a graph showing the relationship between the amount of each binder added and bending strength.
  • 1 is a graph showing the amount of sand remaining on the casting surface after sand removal for each aggregate.
  • 1 is a graph showing the amount of sand remaining on the casting surface after sand removal for each binder.
  • a mold making method makes a mold.
  • the mold is a main mold or a core for producing an iron-based casting.
  • the iron-based casting is a casting in which the molten metal used for production contains iron oxide (FeO), such as cast iron.
  • FeO iron oxide
  • FIG. 1 is a flow chart of a mold making method according to one embodiment.
  • a kneading process (step S10) is first performed.
  • aggregate and binder are mixed in a kneader.
  • the aggregate is artificial sand having 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ).
  • the percentages used here indicate the average values of the components of one grain of sand.
  • the aggregate is artificial sand having 61% or more and 72% or less aluminum oxide (Al 2 O 3 ) and 20% or more and 36% or less silicon dioxide (SiO 2 ).
  • the artificial sand is in the form of particles, and as an example, spherical particles.
  • the artificial sand is manufactured by, for example, a sintering method or a melting method.
  • the sintering method is a method in which fine particles are granulated using a spray dryer or an agitator mixer, and then sintered in a rotary kiln.
  • the melting method is a method in which fine particles are granulated and then melted, or the material is melted in an arc furnace and then granulated by atomization.
  • Artificial sand produced by the fusion method tends to have a smaller specific surface area than artificial sand produced by the sintering method. For this reason, when molding using artificial sand produced by the fusion method, the amount of binder used to solidify the artificial sand can be reduced compared to when molding using artificial sand produced by the sintering method. This allows this mold-making method to reduce manufacturing costs.
  • the binder is either sodium silicate or potassium silicate.
  • the binder is 4 parts by weight or less per 100 parts by weight of aggregate. In other words, this means that the binder is 4 g or less per 100 g of aggregate. As an example, the binder is 1 part by weight or more and 4 parts by weight or less per 100 parts by weight of aggregate.
  • the binder may have a molar ratio of 1.8 or more.
  • the aggregate and the binder may be foamed while being mixed.
  • a surfactant may be added.
  • An example of the surfactant is an anionic surfactant.
  • the foamed sand is a mixture of solid particles and a foamed liquid.
  • the foamed sand is a mixture of aggregate, binder, and surfactant.
  • the foamed sand may contain not only aggregate, binder, and surfactant, but also other materials.
  • the foamed sand may further contain at least one of poorly water-soluble inorganic compound particles and a lithium salt.
  • “Poorly water-soluble” means that the amount of dissolution is 100 mg or less when dissolved in 1 L of water at 25°C.
  • the inorganic compound particles are, for example, carbonates or hydroxides, and examples are calcium carbonate, magnesium carbonate, magnesium hydroxide, or aluminum hydroxide.
  • Examples of lithium salts are lithium silicate, lithium oxide, lithium hydroxide, lithium carbonate, lithium bromide, lithium chloride, lithium nitrate, or lithium nitrite. Using foamed mixed sand improves the filling properties of the sand.
  • the filling process (step S12) is carried out.
  • the mixed sand an example of a mold material
  • the filling method may be changed depending on the type of solidification method described below. Examples of filling methods include blowing, which uses airflow to fill the mold, injection such as pressing, manual filling, filling by vibration, or squeezing.
  • a solidification process (step S14) is performed.
  • the mixed sand filled in the mold is solidified.
  • the solidification method is not particularly limited.
  • a method using a dehydration condensation reaction a method of hardening a binder with carbon dioxide (CO 2 ) gas, a method of mixing 2 to 4% slag with aggregate and using the slag as a hardener, a method of simultaneously adding an ester and an additive to aggregate and kneading the aggregate to gel, a method of reacting metal powder with an alkali additive to harden the aggregate, and the like can be adopted.
  • the solidification process (step S14) the flow chart shown in FIG. 1 is completed. After the solidification is completed, the main mold or the core is removed from the mold.
  • step S14 When a dehydration condensation reaction is used in the solidification process (step S14), the heated metal mold is filled with the foamed mixed sand in the filling process (step S12).
  • the binder is hardened with carbon dioxide (CO 2 ) gas in the solidification process (step S14)
  • the wooden mold, resin mold, or (heated) metal mold is filled with the mixed sand in the filling process (step S12).
  • solidification by a dehydration condensation reaction is employed, or when solidification using carbon dioxide (CO 2 ) gas is employed, a foundry with less odor and a better environment can be realized compared to other methods.
  • the silicon dioxide (SiO 2 ) contained in the aggregate is 40% or less, and the content of silicon dioxide (SiO 2 ) is significantly reduced compared to natural silica sand containing 90% or more of silicon dioxide (SiO 2 ). Therefore, the mold made by the mold-making method according to the embodiment is less likely to generate fayalite (2FeO.SiO 2 ) compared to a mold made using natural silica sand as aggregate. Therefore, the mold-making method according to the embodiment can suppress the occurrence of seizure defects and insertion defects on the casting surface compared to a mold made using natural silica sand as aggregate. Furthermore, since fayalite (2FeO.SiO 2 ) is less likely to be generated, there is no need to apply a mold coat. Therefore, the mold-making method according to the embodiment can suppress the occurrence of defects without reducing productivity.
  • the mold-making method according to the embodiment can improve the collapseability of the mold while maintaining its strength.
  • Test 1 Mold strength evaluation
  • Examples and comparative examples were produced by varying the type of aggregate and the amount of binder added, and the mold strength was evaluated.
  • the binder was No. 1 water glass (manufactured by Fuji Chemical Co., Ltd.), and the surfactant was an anionic surfactant.
  • Example 1 Artificial sand 1 was used as aggregate. 100 parts by weight of artificial sand 1, 1 part by weight of binder, and 0.25 parts by weight of surfactant were mixed and foamed for about 5 minutes using a kneader (tabletop mixer: manufactured by Aikosha Seisakusho) at about 200 rpm to prepare foamed mixed sand. Next, this foamed mixed sand was filled into a mold heated to 250°C using an injection filling device. The mold was a mold for preparing bending strength test pieces and had a cavity with a capacity of about 80 cm3 . It was filled at a gate speed of about 1 m/sec and a cylinder surface pressure of 0.4 MPa. The foamed mixed sand filled into this heated mold was left for 2 minutes, and the foamed mixed sand was solidified by a dehydration condensation reaction due to the heat of the mold. After solidification was completed, the core was removed from the mold.
  • a kneader tablette: manufactured by Aiko
  • Example 2 (Examples 2 to 6)
  • the binder was 2 parts by weight.
  • the rest was the same as Example 1.
  • the binder was 4 parts by weight.
  • the rest was the same as Example 1.
  • artificial sand 2 was used as the aggregate.
  • the rest was the same as Example 1.
  • artificial sand 2 was used as the aggregate.
  • the rest was the same as Example 2.
  • artificial sand 2 was used as the aggregate.
  • the rest was the same as Example 3.
  • Sand test pieces measuring 10 mm x 10 mm x 140 mm were prepared from Examples 1 to 6 and Comparative Examples 1 to 6, and their bending strength was measured. The bending strength was measured in accordance with JACT test method SM-1, bending strength test method. The results are shown in Figure 2.
  • Figure 2 is a graph showing the relationship between the amount of binder added for each aggregate and bending strength.
  • the horizontal axis is the amount of binder added (parts by weight) and the vertical axis is bending strength (MPa). Cores used in casting are required to be strong enough not to break during transportation or when the cores are placed in place. For this reason, a bending strength of 3 MPa or more was set as the required strength, and the measurement results were evaluated.
  • the dashed line in the figure is a regression curve. As shown in Figure 2, in the case of artificial sand 1 in Examples 1 to 3, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 1 part by weight.
  • the natural silica sand 2 of Comparative Examples 4 to 6 it is considered that 5.0 parts by weight of the binder is required to achieve a bending strength of 3 MPa or more, based on the estimation from the regression curve. In this way, it was confirmed that by using artificial sand as aggregate, strength can be ensured with a smaller amount of binder than natural silica sand. It is considered that such a difference in the measurement results is influenced by the difference in shape and specific surface area between the artificial sand and the natural silica sand. Since the artificial sand has a smooth surface and the natural silica sand has many irregularities on the surface, the artificial sand has a smaller specific surface area, and it is considered that the desired strength can be obtained even with a smaller amount of binder used.
  • the aggregate was artificial sand 1 in Table 1, and the surfactant was an anionic surfactant.
  • Example 7 The aggregate used was artificial sand 1.
  • the artificial sand 1 was 100 parts by weight, the binder 1 was 1 part by weight, and the surfactant was 0.25 parts by weight.
  • the preparation conditions were the same as those in Example 1.
  • Example 8 In Examples 8 and 9, the amount of binder 1 was 2 parts by weight and 4 parts by weight. The rest was the same as Example 7. In Examples 10 to 12, the amount of binder 2 was 1, 2, and 4 parts by weight. The rest was the same as Example 7. In Examples 13 to 15, the amount of binder 3 was 1, 2, and 4 parts by weight. The rest was the same as Example 7. In Examples 16 to 18, the amount of binder 4 was 1, 2, and 4 parts by weight. The rest was the same as Example 7.
  • Sand test pieces measuring 10 mm x 10 mm x 140 mm were prepared from Examples 7 to 18, and their bending strength was measured. The bending strength was measured in accordance with JACT test method SM-1, bending strength test method. The results are shown in Figure 3.
  • Figure 3 is a graph showing the relationship between the amount of each binder added and the bending strength.
  • the horizontal axis is the amount of binder added (parts by weight) and the vertical axis is the bending strength (MPa).
  • MPa bending strength
  • a bending strength of 3 MPa or more was set as the required strength, and the measurement results were evaluated.
  • the dashed line in the figure is a regression curve.
  • FIG 3 in the case of binder 1 in Examples 7 to 9 (Examples 1 to 3), it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 1 part by weight.
  • binder 2 in Examples 10 to 12 it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 4 parts by weight (approximately 2.5 parts by weight estimated from the regression curve).
  • binder 3 in Examples 13 to 15 it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 2 parts by weight (approximately 1.5 parts by weight estimated from the regression curve).
  • binder 4 in Examples 16 to 18 it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 4 parts by weight. In this way, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 1 to 4 parts by weight. Furthermore, it was confirmed that with any binder, a bending strength of 3 MPa or more was achieved with at least 4 parts by weight.
  • Example 19 a core was prepared from 100 parts by weight of artificial sand 1, 1 part by weight of binder 1, and 0.25 parts by weight of anionic surfactant.
  • Example 20 a core was prepared from 100 parts by weight of artificial sand 2, 2.5 parts by weight of binder 1, and 0.25 parts by weight of anionic surfactant.
  • Comparative Example 7 a core was prepared from 100 parts by weight of natural silica sand 1, 3.5 parts by weight of binder 1, and 0.25 parts by weight of anionic surfactant.
  • Comparative Example 8 a core was prepared from 100 parts by weight of natural silica sand 2, 5.0 parts by weight of binder 1, and 0.25 parts by weight of anionic surfactant.
  • the preparation conditions for Examples 19 and 20 and Comparative Examples 7 and 8 were the same as those for Example 1, and a core measuring 10 mm x 10 mm x 140 mm was obtained.
  • Example 21 100 parts by weight of artificial sand 1 and 1 part by weight of binder 1 were mixed for about 5 minutes at about 200 rpm using a mixer (tabletop mixer: Aikosha Seisakusho) to prepare wet mixed sand. This mixed sand was then manually filled into a wooden mold. A wooden mold capable of casting a 30 mm x 30 mm x 100 mm casting and molding a master mold capable of housing a 10 mm x 10 mm x 140 mm core was used. Carbon dioxide ( CO2 ) was blown into the mixed sand filled into the wooden mold for 30 seconds to solidify it. After solidification was complete, the master mold was removed from the wooden mold.
  • a mixer tabletop mixer: Aikosha Seisakusho
  • Example 22 Comparative Examples 9 and 10
  • the master mold was made with 100 parts by weight of artificial sand 2 and 2.5 parts by weight of binder 1.
  • the master mold was made with 100 parts by weight of natural silica sand 1 and 3.5 parts by weight of binder 1.
  • the master mold was made with 100 parts by weight of natural silica sand 2 and 5.0 parts by weight of binder 1.
  • the production conditions for Example 22 and Comparative Examples 9 and 10 are the same as those for Example 21.
  • Cast iron FC200 was cast using the core and main mold in casting number 1. Casting was performed without coating the core and main mold. After casting, the sprue was struck 10 times with a hammer to remove sand from the casting, and the core was visually inspected for collapse and the weight of sand adhering to the casting was measured. For casting numbers 2 to 4, the core was visually inspected for collapse under the same conditions and the weight of sand adhering to the casting was measured.
  • FIG. 4 is a graph showing the amount of sand remaining on the casting surface after sand removal for each aggregate.
  • the horizontal axis is the casting number, and the vertical axis is the amount of remaining sand.
  • the amount of remaining sand was about 2 g in casting No. 1, where the aggregate was artificial sand, and about 6 g in casting No. 2, where the aggregate was artificial sand.
  • the amount of remaining sand was about 36 g in casting No. 3, where the aggregate was natural silica sand, and about 32 g in casting No. 4, where the aggregate was natural silica sand.
  • the natural silica sand was hardened to surround the casting. Since the natural silica sand caused a seizure defect, the weight of the natural silica sand that could be removed from the casting with a metal file was measured. Thus, it was confirmed that it is difficult to achieve both strength and collapsibility of the main mold when natural silica sand is used as the aggregate. It was also confirmed that it is possible to achieve both strength and collapsibility of the main mold by using artificial sand as the aggregate.
  • Table 7 shows the parts by weight of each binder required to achieve a bending strength of 3 MPa or more in artificial sand 1, which was estimated from the results of Test 2.
  • Example 23 a core was made with 100 parts by weight of artificial sand 1, 1 part by weight of binder 1, and 0.25 parts by weight of anionic surfactant.
  • Example 24 a core was made with 100 parts by weight of artificial sand 1, 2.5 parts by weight of binder 2, and 0.25 parts by weight of anionic surfactant.
  • Example 25 a core was made with 100 parts by weight of artificial sand 1, 1.5 parts by weight of binder 3, and 0.25 parts by weight of anionic surfactant.
  • Example 26 a core was made with 100 parts by weight of artificial sand 1, 4.0 parts by weight of binder 4, and 0.25 parts by weight of anionic surfactant.
  • the preparation conditions for Examples 23 to 26 were the same as those for Example 1.
  • Example 27 the master mold was made with 100 parts by weight of artificial sand 1 and 1 part by weight of binder 1.
  • the master mold was made with 100 parts by weight of artificial sand 1 and 2.5 parts by weight of binder 2.
  • the master mold was made with 100 parts by weight of artificial sand 1 and 1.5 parts by weight of binder 3.
  • the master mold was made with 100 parts by weight of artificial sand 1 and 4.0 parts by weight of binder 4.
  • the production conditions for Examples 27 to 30 were the same as those for Example 21.
  • Cast iron FC200 was cast using the core and main mold in casting number 5. Casting was performed without coating the core and main mold. After casting, the sprue was struck 10 times with a hammer to remove sand from the casting, and the core was visually inspected for collapse and the weight of sand adhering to the casting was measured. For casting numbers 6 to 8, the core was visually inspected for collapse under the same conditions and the weight of sand adhering to the casting was measured.
  • Figure 5 is a graph showing the amount of sand remaining on the casting surface after sand removal for each binder.
  • the horizontal axis is the casting number, and the vertical axis is the amount of remaining sand.
  • the amount of remaining sand was 4g or less for casting numbers 5 to 8, in which the aggregate was artificial sand, and it was confirmed that, regardless of the type of binder, when the aggregate was artificial sand, only a small amount of sand adhered to the casting. It was also confirmed that, regardless of the type of binder, by using artificial sand as the aggregate, it was possible to achieve both strength and collapsibility of the main mold.
  • a mold making method for making a mold for producing an iron-based casting comprising the steps of: A step of producing mixed sand using artificial sand as aggregate and a binder; Filling the mixed sand into a mold; A step of solidifying the mixed sand filled in the mold; A mold making method comprising: [Clause 2] 2.
  • Al 2 O 3 aluminum oxide
  • SiO 2 silicon dioxide
  • a mold material for a mold for producing iron-based castings comprising artificial sand containing 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ) as aggregate, and containing either sodium silicate or potassium silicate as a binder.

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Abstract

This cast shaping method is for shaping a cast for manufacturing an iron-based cast object, the method including: a step for producing kneading sand by using a binder and artificial sand which is the aggregate; a step for filling the kneading sand into a mold; and a step for solidifying the kneading sand filled into the mold.

Description

鋳型造型方法及び鋳型材料Mold making method and mold material
　本開示は、鋳型造型方法及び鋳型材料に関する。 This disclosure relates to a mold making method and mold material.
　特許文献１は、鋳型を開示する。鋳型は、成型された珪砂を、バインダーを用いて粘結させることで製造される。珪砂の主成分は、二酸化ケイ素（ＳｉＯ２）である。 Patent Document 1 discloses a mold. The mold is produced by binding molded silica sand with a binder. The main component of silica sand is silicon dioxide (SiO 2 ).
特表２０１４－５２７９１５号公報JP 2014-527915 A
　特許文献１記載の鋳型を鉄系鋳物の製造に用いる場合、溶湯中の金属酸化物（例えばＦｅＯ）が鋳型の骨材である珪砂に含まれる二酸化ケイ素（ＳｉＯ２）と反応し、ファイアライト（２ＦｅＯ・ＳｉＯ２）が生成される場合がある。ファイアライト（２ＦｅＯ・ＳｉＯ２）は、鋳物表面の焼付き欠陥を引き起こしたり、差し込み不良を発生させたりするおそれがある。不良を低減するために、例えば鋳型に塗型を塗ることが考えられる。しかしながら、製造工程が増えるため、生産性が低下する。本開示は、鉄系鋳物を製造する鋳型の造型において、生産性を低下させることなく不良の発生を抑える技術を提供する。 When the mold described in Patent Document 1 is used to manufacture iron-based castings, metal oxides (e.g., FeO) in the molten metal may react with silicon dioxide (SiO 2 ) contained in silica sand, which is the aggregate of the mold, to generate fayalite (2FeO.SiO 2 ). Fayalite (2FeO.SiO 2 ) may cause seizure defects on the surface of the casting or cause insertion failure. In order to reduce the defects, for example, it is possible to apply a mold coat to the mold. However, this increases the number of manufacturing steps, which reduces productivity. The present disclosure provides a technique for suppressing the occurrence of defects without reducing productivity in the molding of molds for manufacturing iron-based castings.
　本開示の一側面に係る鋳型造型方法は、鉄系鋳物を製造する鋳型を造型する方法である。方法は、以下ステップを含む。
（１）骨材である人工砂と粘結剤とを用いて混練砂を生成するステップ
（２）混練砂を型に充填するステップ
（３）型に充填された混練砂を固化させるステップ A method for making a mold for producing a ferrous casting according to one aspect of the present disclosure includes the following steps:
(1) A step of producing mixed sand using artificial sand as aggregate and a binder; (2) A step of filling the mixed sand into a mold; and (3) A step of solidifying the mixed sand filled into the mold.
　この鋳型造型方法では、人工砂を骨材とするため、二酸化ケイ素（ＳｉＯ２）を９０％以上含む天然珪砂と比べて、二酸化ケイ素（ＳｉＯ２）の含有量が大きく抑えられる。このため、この鋳型造型方法によって製造された鋳型は、天然珪砂を骨材として製造された鋳型と比べて、ファイアライト（２ＦｅＯ・ＳｉＯ２）が発生しにくい。よって、この鋳型造型方法は、天然珪砂を骨材とした場合と比べて、鋳物表面の焼付き欠陥及び差し込み不良の発生を抑制できる。さらに、ファイアライト（２ＦｅＯ・ＳｉＯ２）が発生しにくいことから、塗型を塗る必要もない。このため、この鋳型造型方法は、生産性を低下させることなく不良の発生を抑えることができる。 In this mold-making method, since artificial sand is used as aggregate, the content of silicon dioxide (SiO 2 ) is significantly reduced compared to natural silica sand, which contains 90% or more of silicon dioxide (SiO 2 ). Therefore, the mold made by this mold-making method is less likely to generate fayalite (2FeO.SiO 2 ) compared to molds made using natural silica sand as aggregate. Therefore, this mold-making method can suppress the occurrence of seizure defects and insertion defects on the casting surface compared to when natural silica sand is used as aggregate. Furthermore, since fayalite (2FeO.SiO 2 ) is less likely to be generated, there is no need to apply a mold coat. Therefore, this mold-making method can suppress the occurrence of defects without reducing productivity.
　一実施形態においては、人工砂は、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下であり、粘結剤は、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方であってもよい。 In one embodiment, the artificial sand contains 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ), and the binder may be either sodium silicate or potassium silicate.
　一実施形態においては、粘結剤はモル比が１．８以上であってもよい。この場合、鋳型造型方法は、鋳型の強度を保ちつつ鋳型の崩壊性を改善できる。 In one embodiment, the binder may have a molar ratio of 1.8 or more. In this case, the mold making method can improve the collapse property of the mold while maintaining the strength of the mold.
　一実施形態においては、粘結剤は骨材１００重量部に対して４重量部以下であってもよい。鋳型の強度を確保するためには粘結剤を多めに添加する必要がある。天然珪砂を骨材とする場合には、一般的に粘結剤は４重量部よりも多く添加される。しかしながら、粘結剤を多めに添加した場合、鋳型の崩壊性が悪化する。この鋳型造型方法では、骨材に人工砂を採用することにより、粘結剤の添加量が４重量部以下であっても鋳型の強度を十分に得ることができる。よって、この鋳型造型方法は、鋳型の強度を保ちつつ鋳型の崩壊性を改善できる。 In one embodiment, the binder may be 4 parts by weight or less per 100 parts by weight of aggregate. In order to ensure the strength of the mold, it is necessary to add a larger amount of binder. When natural silica sand is used as the aggregate, generally more than 4 parts by weight of binder is added. However, if too much binder is added, the collapseability of the mold deteriorates. In this mold making method, by using artificial sand as the aggregate, it is possible to obtain sufficient strength of the mold even if the amount of binder added is 4 parts by weight or less. Therefore, this mold making method can improve the collapseability of the mold while maintaining the strength of the mold.
　一実施形態においては、人工砂は溶融法又は焼結法により製造されてもよい。溶融法又は焼結法により製造された人工砂は、他の方法で製造された人工砂と比べて粘結剤の量を少なくできるので、この鋳型造型方法は製造コストを削減できる。 In one embodiment, the artificial sand may be produced by a melting or sintering process. This mold-making method can reduce production costs because artificial sand produced by the melting or sintering process can require less binder than artificial sand produced by other methods.
　一実施形態においては、固化させるステップでは、脱水縮合反応によって混練砂を固化させてもよい。脱水縮合反応による固化を採用した場合、充填するステップでは、加熱された金型に、湿態の混練砂をブロー充填したり、発泡混練砂を射出充填したりできる。この鋳型造型方法は、臭いが少なく環境の良い鋳造工場が実現できる。一方で、エステルを用いて固化させる場合には、有機物特有の臭いが発生し、金属粉と水ガラスとを反応させて固化させる場合には、水素が発生する。 In one embodiment, the solidification step may involve solidifying the mixed sand through a dehydration condensation reaction. When solidification through a dehydration condensation reaction is used, the filling step may involve blow-filling wet mixed sand into a heated mold, or injecting foamed mixed sand into the mold. This mold-making method allows for the creation of environmentally friendly foundries with little odor. On the other hand, when solidification is performed using an ester, an odor specific to organic matter is generated, and when solidification is performed by reacting metal powder with water glass, hydrogen is generated.
　一実施形態においては、固化させるステップでは、二酸化炭素（ＣＯ２）ガスを用いて混練砂を固化させてもよい。二酸化炭素（ＣＯ２）ガスを用いた固化を採用した場合、充填するステップでは、湿態の混練砂を手込め、振動充填、スクイズ、又はブロー充填によって充填できる。この鋳型造型方法は、臭いが少なく環境の良い鋳造工場が実現できる。一方で、エステルを用いて固化させる場合には、有機物特有の臭いが発生し、金属粉と水ガラスとを反応させて固化させる場合には、水素が発生する。 In one embodiment, the solidifying step may solidify the mixed sand using carbon dioxide (CO 2 ) gas. When solidifying using carbon dioxide (CO 2 ) gas is adopted, the wet mixed sand can be filled by hand filling, vibration filling, squeezing, or blow filling in the filling step. This mold making method can realize a foundry with less odor and a good environment. On the other hand, when solidifying using ester, an odor specific to organic matter is generated, and when solidifying by reacting metal powder with water glass, hydrogen is generated.
　一実施形態においては、混練砂は界面活性剤を含む発泡混練砂であってもよい。この鋳型造型方法は、人工砂を骨材とする発泡混練砂を用いることで、砂の充填性を向上させつつ、生産性を低下させることなく不良の発生を抑えることができる。 In one embodiment, the mixed sand may be expanded mixed sand containing a surfactant. By using expanded mixed sand with artificial sand as aggregate, this mold making method can improve the filling properties of the sand while suppressing the occurrence of defects without reducing productivity.
　本開示の他の側面に係る鋳型材料は、鉄系鋳物を製造する鋳型の材料である。鋳型材料は、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下である人工砂を骨材とし、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方を粘結剤として含む。この鋳型材料は、骨材に含まれる、二酸化ケイ素（ＳｉＯ２）が４０％以下であり、二酸化ケイ素（ＳｉＯ２）を９０％以上含む天然珪砂と比べて、二酸化ケイ素（ＳｉＯ２）の含有量が大きく抑えられる。このため、この鋳型材料を用いて製造された鋳型は、天然珪砂を骨材として製造された鋳型と比べて、ファイアライト（２ＦｅＯ・ＳｉＯ２）が発生しにくい。よって、この鋳型材料は、天然珪砂を骨材とした場合と比べて、鋳物表面の焼付き欠陥及び差し込み不良の発生を抑制できる。さらに、ファイアライト（２ＦｅＯ・ＳｉＯ２）が発生しにくいことから、塗型を塗る必要もない。このため、この鋳型材料は、生産性を低下させることなく不良の発生を抑えることができる。 A mold material according to another aspect of the present disclosure is a material for a mold for producing an iron-based casting. The mold material contains artificial sand containing 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ) as an aggregate, and either one of sodium silicate or potassium silicate as a binder. This mold material contains 40% or less silicon dioxide (SiO 2 ) as an aggregate, and the content of silicon dioxide (SiO 2 ) is significantly reduced compared to natural silica sand containing 90% or more silicon dioxide (SiO 2 ). Therefore, a mold produced using this mold material is less likely to generate fayalite (2FeO.SiO 2 ) compared to a mold produced using natural silica sand as an aggregate. Therefore, this mold material can suppress the occurrence of seizure defects and insertion failures on the surface of the casting compared to a case in which natural silica sand is used as an aggregate. Furthermore, since fayalite (2FeO.SiO 2 ) is unlikely to be generated, there is no need to apply a mold coat, and therefore this mold material can suppress the occurrence of defects without reducing productivity.
　本開示によれば、鉄系鋳物を製造する鋳型の造型において、生産性を低下させることなく不良の発生を抑えることができる技術が提供される。 This disclosure provides a technology that can reduce the occurrence of defects in the molding of molds for producing iron-based castings without reducing productivity.
一実施形態に係る鋳型造型方法のフローチャートである。1 is a flowchart of a mold making method according to one embodiment. 各骨材における粘結剤の添加量と曲げ強度との関係を示すグラフである。1 is a graph showing the relationship between the amount of binder added and bending strength for each aggregate. 各粘結剤の添加量と曲げ強度との関係を示すグラフである。1 is a graph showing the relationship between the amount of each binder added and bending strength. 各骨材における砂落とし後の鋳肌への砂残量を示すグラフである。1 is a graph showing the amount of sand remaining on the casting surface after sand removal for each aggregate. 各粘結剤における砂落とし後の鋳肌への砂残量を示すグラフである。1 is a graph showing the amount of sand remaining on the casting surface after sand removal for each binder.
　以下、本発明の実施形態について図面を参照して説明する。各図面において同一又は相当の部分に対しては同一の符号を附す。 Below, an embodiment of the present invention will be described with reference to the drawings. The same or equivalent parts in each drawing are given the same reference numerals.
（鋳型造型方法の概要）
　一実施形態に係る鋳型造型方法は、鋳型を造型する。鋳型は、鉄系鋳物を製造する主型又は中子である。鉄系鋳物とは、製造に用いられる溶湯に酸化鉄（ＦｅＯ）が含有されている鋳物であり、鋳鉄などである。 (Outline of the casting method)
A mold making method according to one embodiment makes a mold. The mold is a main mold or a core for producing an iron-based casting. The iron-based casting is a casting in which the molten metal used for production contains iron oxide (FeO), such as cast iron.
　図１は、一実施形態に係る鋳型造型方法のフローチャートである。図１に示されるように、鋳型造型方法においては、最初に混練処理（ステップＳ１０）が実行される。混練処理（ステップＳ１０）では、混練機で骨材と粘結剤とが混合される。 FIG. 1 is a flow chart of a mold making method according to one embodiment. As shown in FIG. 1, in the mold making method, a kneading process (step S10) is first performed. In the kneading process (step S10), aggregate and binder are mixed in a kneader.
　骨材は、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下である人工砂である。ここでの％表記は、砂一粒の成分の平均値についての表示である。より具体的な一例としては、骨材は、酸化アルミニウム（Ａｌ２Ｏ３）が６１％以上かつ７２％以下であって、二酸化ケイ素（ＳｉＯ２）が２０％以上かつ３６％以下である人工砂である。人工砂は、粒子であり、一例として球状粒子である。人工砂は、例えば、焼結法又は溶融法により製造される。 The aggregate is artificial sand having 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ). The percentages used here indicate the average values of the components of one grain of sand. As a more specific example, the aggregate is artificial sand having 61% or more and 72% or less aluminum oxide (Al 2 O 3 ) and 20% or more and 36% or less silicon dioxide (SiO 2 ). The artificial sand is in the form of particles, and as an example, spherical particles. The artificial sand is manufactured by, for example, a sintering method or a melting method.
　焼結法は、スプレードライヤ又はアジテータミキサで微粒子を造粒した後に、ロータリーキルンで微粒子を焼結する方法である。溶融法は、微粒子を造粒した後に、微粒子を溶融させる方法、又は、アーク炉で材料を溶融させた後にアトマイジングにより粒子化する方法である。 The sintering method is a method in which fine particles are granulated using a spray dryer or an agitator mixer, and then sintered in a rotary kiln. The melting method is a method in which fine particles are granulated and then melted, or the material is melted in an arc furnace and then granulated by atomization.
　溶融法により製造された人工砂は、焼結法で製造された人工砂と比べて比表面積が小さくなる傾向にある。このため、溶融法により製造された人工砂を用いて造型した場合、焼結法で製造された人工砂を用いて造型した場合と比べて、人工砂を固化させる粘結剤の量を少なくできる。これにより、この鋳型造型方法は、製造コストを削減できる。 Artificial sand produced by the fusion method tends to have a smaller specific surface area than artificial sand produced by the sintering method. For this reason, when molding using artificial sand produced by the fusion method, the amount of binder used to solidify the artificial sand can be reduced compared to when molding using artificial sand produced by the sintering method. This allows this mold-making method to reduce manufacturing costs.
　粘結剤は、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方である。粘結剤は、骨材１００重量部に対して４重量部以下である。つまり、骨材１００ｇに対して粘結剤は４ｇ以下という意味である。粘結剤は、一例として骨材１００重量部に対して１重量部以上４重量部以下である。粘結剤は、モル比が１．８以上であってもよい。 The binder is either sodium silicate or potassium silicate. The binder is 4 parts by weight or less per 100 parts by weight of aggregate. In other words, this means that the binder is 4 g or less per 100 g of aggregate. As an example, the binder is 1 part by weight or more and 4 parts by weight or less per 100 parts by weight of aggregate. The binder may have a molar ratio of 1.8 or more.
　混練処理（ステップＳ１０）では、骨材と粘結剤とを混合させながら発泡させてもよい。この場合、界面活性剤が添加され得る。界面活性剤は、一例としてアニオン界面活性剤である。これにより、ホイップクリーム状の発泡混練砂が得られる。発泡混練砂とは、固体粒子と発泡した液体との混練砂である。発泡混練砂は、骨材、粘結剤、及び、界面活性剤を混合させたものである。発泡混練砂は、骨材、粘結剤、及び、界面活性剤だけでなく、他の材料を含んでもよい。例えば、発泡混練砂は、難水溶性の無機化合物粒子、及び、リチウム塩の少なくとも一方をさらに含んでもよい。「難水溶性」とは、２５℃の水１Ｌ中に溶解させたときにその溶解量が１００ｍｇ以下であることである。無機化合物粒子は、例えば炭酸塩又は水酸化物であり、一例として炭酸カルシウム、炭酸マグネシウム、水酸化マグネシウム、又は水酸化アルミニウムである。リチウム塩の一例は、珪酸リチウム、酸化リチウム、水酸化リチウム、炭酸リチウム、臭化リチウム、塩化リチウム、硝酸リチウム、又は、亜硝酸リチウムである。発泡混練砂を用いることで、砂の充填性が向上する。 In the kneading process (step S10), the aggregate and the binder may be foamed while being mixed. In this case, a surfactant may be added. An example of the surfactant is an anionic surfactant. This results in a whipped cream-like foamed sand. The foamed sand is a mixture of solid particles and a foamed liquid. The foamed sand is a mixture of aggregate, binder, and surfactant. The foamed sand may contain not only aggregate, binder, and surfactant, but also other materials. For example, the foamed sand may further contain at least one of poorly water-soluble inorganic compound particles and a lithium salt. "Poorly water-soluble" means that the amount of dissolution is 100 mg or less when dissolved in 1 L of water at 25°C. The inorganic compound particles are, for example, carbonates or hydroxides, and examples are calcium carbonate, magnesium carbonate, magnesium hydroxide, or aluminum hydroxide. Examples of lithium salts are lithium silicate, lithium oxide, lithium hydroxide, lithium carbonate, lithium bromide, lithium chloride, lithium nitrate, or lithium nitrite. Using foamed mixed sand improves the filling properties of the sand.
　混練処理（ステップＳ１０）にて混練砂の調整が終了すると、充填処理（ステップＳ１２）が実行される。充填処理（ステップＳ１２）では、混練砂（鋳型材料の一例）を型に充填する。充填の方法は特に限定されない。充填方法は、後述の固化方法の種類に応じて変更してもよい。充填の方法は、一例として、空気流によって充填させるブロー、圧入などの射出、手作業による手込め、振動による充填、又は、スクイズである。 Once the preparation of the mixed sand in the mixing process (step S10) is completed, the filling process (step S12) is carried out. In the filling process (step S12), the mixed sand (an example of a mold material) is filled into the mold. There are no particular limitations on the filling method. The filling method may be changed depending on the type of solidification method described below. Examples of filling methods include blowing, which uses airflow to fill the mold, injection such as pressing, manual filling, filling by vibration, or squeezing.
　充填処理（ステップＳ１２）にて混練砂の充填が終了すると、固化処理（ステップＳ１４）が実行される。固化処理（ステップＳ１４）では、型に充填された混練砂を固化させる。固化の方法は特に限定されない。固化の方法は、一例として、脱水縮合反応を利用する方法、二酸化炭素（ＣＯ２）ガスで粘結剤を硬化させる方法、骨材に２～４％ほどスラグを混ぜておき、スラグを硬化剤とする方法、骨材にエステルと添加剤とを同時に添加して混練することでゲル化させる方法、金属粉と添加剤のアルカリとを反応させて硬化させる方法などを採用できる。固化処理（ステップＳ１４）が終了すると、図１に示されるフローチャートは終了する。固化終了後、型から主型又は中子が取り出される。 When the filling of the mixed sand is completed in the filling process (step S12), a solidification process (step S14) is performed. In the solidification process (step S14), the mixed sand filled in the mold is solidified. The solidification method is not particularly limited. As an example of the solidification method, a method using a dehydration condensation reaction, a method of hardening a binder with carbon dioxide (CO 2 ) gas, a method of mixing 2 to 4% slag with aggregate and using the slag as a hardener, a method of simultaneously adding an ester and an additive to aggregate and kneading the aggregate to gel, a method of reacting metal powder with an alkali additive to harden the aggregate, and the like can be adopted. When the solidification process (step S14) is completed, the flow chart shown in FIG. 1 is completed. After the solidification is completed, the main mold or the core is removed from the mold.
　なお、固化処理（ステップＳ１４）において脱水縮合反応を利用する場合には、充填処理（ステップＳ１２）では、加熱された金型に発泡混練砂を充填させる。固化処理（ステップＳ１４）において二酸化炭素（ＣＯ２）ガスで粘結剤を硬化させる場合には、充填処理（ステップＳ１２）では、木型、樹脂型または（加熱）金型に混練砂を充填させる。脱水縮合反応による固化を採用した場合、及び、二酸化炭素（ＣＯ２）ガスを用いた固化を採用した場合には、他の方法と比べて、臭いが少なく環境の良い鋳造工場が実現できる。 When a dehydration condensation reaction is used in the solidification process (step S14), the heated metal mold is filled with the foamed mixed sand in the filling process (step S12). When the binder is hardened with carbon dioxide (CO 2 ) gas in the solidification process (step S14), the wooden mold, resin mold, or (heated) metal mold is filled with the mixed sand in the filling process (step S12). When solidification by a dehydration condensation reaction is employed, or when solidification using carbon dioxide (CO 2 ) gas is employed, a foundry with less odor and a better environment can be realized compared to other methods.
（実施形態のまとめ）
　実施形態に係る鋳型造型方法では、骨材に含まれる二酸化ケイ素（ＳｉＯ２）が４０％以下であり、二酸化ケイ素（ＳｉＯ２）を９０％以上含む天然珪砂と比べて、二酸化ケイ素（ＳｉＯ２）の含有量が大きく抑えられる。このため、実施形態に係る鋳型造型方法によって製造された鋳型は、天然珪砂を骨材として製造された鋳型と比べて、ファイアライト（２ＦｅＯ・ＳｉＯ２）が発生しにくい。よって、実施形態に係る鋳型造型方法は、天然珪砂を骨材とした場合と比べて、鋳物表面の焼付き欠陥及び差し込み不良の発生を抑制できる。さらに、ファイアライト（２ＦｅＯ・ＳｉＯ２）が発生しにくいことから、塗型を塗る必要もない。このため、実施形態に係る鋳型造型方法は、生産性を低下させることなく不良の発生を抑えることができる。 (Summary of the embodiment)
In the mold-making method according to the embodiment, the silicon dioxide (SiO 2 ) contained in the aggregate is 40% or less, and the content of silicon dioxide (SiO 2 ) is significantly reduced compared to natural silica sand containing 90% or more of silicon dioxide (SiO 2 ). Therefore, the mold made by the mold-making method according to the embodiment is less likely to generate fayalite (2FeO.SiO 2 ) compared to a mold made using natural silica sand as aggregate. Therefore, the mold-making method according to the embodiment can suppress the occurrence of seizure defects and insertion defects on the casting surface compared to a mold made using natural silica sand as aggregate. Furthermore, since fayalite (2FeO.SiO 2 ) is less likely to be generated, there is no need to apply a mold coat. Therefore, the mold-making method according to the embodiment can suppress the occurrence of defects without reducing productivity.
　また、鋳型の強度を確保するためには粘結剤を多めに添加する必要がある。天然珪砂を骨材とする場合には、一般的に粘結剤は４重量部よりも多く添加される。しかしながら、粘結剤を多めに添加した場合、鋳型の崩壊性が悪化する。実施形態に係る鋳型造型方法では、骨材に人工砂を採用することにより、粘結剤の添加量が４重量部以下であっても鋳型の強度を十分に得ることができる。よって、実施形態に係る鋳型造型方法は、鋳型の強度を保ちつつ鋳型の崩壊性を改善できる。 Furthermore, to ensure the strength of the mold, it is necessary to add a large amount of binder. When natural silica sand is used as the aggregate, generally more than 4 parts by weight of binder is added. However, adding too much binder deteriorates the collapseability of the mold. In the mold-making method according to the embodiment, by using artificial sand as the aggregate, it is possible to obtain sufficient strength for the mold even if the amount of binder added is 4 parts by weight or less. Therefore, the mold-making method according to the embodiment can improve the collapseability of the mold while maintaining its strength.
　以下、本開示の効果を確認すべく本発明者等が実施した実施例及び比較例について説明される。 Below, examples and comparative examples carried out by the inventors to confirm the effects of this disclosure are described.
［試験１：鋳型強度評価］
　骨材の種類、及び、粘結剤の添加量を変化させた実施例及び比較例を製造し、鋳型強度を評価した。 [Test 1: Mold strength evaluation]
Examples and comparative examples were produced by varying the type of aggregate and the amount of binder added, and the mold strength was evaluated.
（骨材の種類）
　骨材として人工砂を２種類、天然珪砂を２種類用意した。
Figure JPOXMLDOC01-appb-T000001
 (Type of aggregate)
Two types of artificial sand and two types of natural silica sand were prepared as aggregates.
Figure JPOXMLDOC01-appb-T000001
（粘結剤、界面活性剤）
　粘結剤は１号水ガラス（富士化学株式会社製）とし、界面活性剤はアニオン界面活性剤とした。 (Binding agent, surfactant)
The binder was No. 1 water glass (manufactured by Fuji Chemical Co., Ltd.), and the surfactant was an anionic surfactant.
（実施例１）
　骨材として人工砂１を用いた。人工砂１を１００重量部、粘結剤を１重量部、界面活性剤を０．２５重量部とした材料を、混練機（卓上ミキサ：愛工舎製作所製）を用いて約２００ｒｐｍで約５分間、混合・発泡させて、発泡混練砂を調整した。次いで、この発泡混練砂を射出充填装置にて２５０℃に加熱した金型に充填した。金型は曲げ強度試験片作製用の金型で、容量約８０ｃｍ３のキャビティを有する。ゲート速度約１ｍ／ｓｅｃ、シリンダ面圧０．４ＭＰａで充填した。この加熱された金型に充填された発泡混練砂を２分間、放置して、金型の熱による脱水縮合反応によって発泡混練砂を固化させた。固化完了後、金型から中子を取り出した。 Example 1
Artificial sand 1 was used as aggregate. 100 parts by weight of artificial sand 1, 1 part by weight of binder, and 0.25 parts by weight of surfactant were mixed and foamed for about 5 minutes using a kneader (tabletop mixer: manufactured by Aikosha Seisakusho) at about 200 rpm to prepare foamed mixed sand. Next, this foamed mixed sand was filled into a mold heated to 250°C using an injection filling device. The mold was a mold for preparing bending strength test pieces and had a cavity with a capacity of about 80 cm3 . It was filled at a gate speed of about 1 m/sec and a cylinder surface pressure of 0.4 MPa. The foamed mixed sand filled into this heated mold was left for 2 minutes, and the foamed mixed sand was solidified by a dehydration condensation reaction due to the heat of the mold. After solidification was completed, the core was removed from the mold.
（実施例２～６）
　実施例２は、粘結剤を２重量部とした。その他は実施例１と同一である。実施例３は、粘結剤を４重量部とした。その他は実施例１と同一である。実施例４は、骨材として人工砂２を用いた。その他は実施例１と同一である。実施例５は、骨材として人工砂２を用いた。その他は実施例２と同一である。実施例６は、骨材として人工砂２を用いた。その他は実施例３と同一である。 (Examples 2 to 6)
In Example 2, the binder was 2 parts by weight. The rest was the same as Example 1. In Example 3, the binder was 4 parts by weight. The rest was the same as Example 1. In Example 4, artificial sand 2 was used as the aggregate. The rest was the same as Example 1. In Example 5, artificial sand 2 was used as the aggregate. The rest was the same as Example 2. In Example 6, artificial sand 2 was used as the aggregate. The rest was the same as Example 3.
（比較例１～６）
　比較例１は、骨材として天然珪砂１を用いた。その他は実施例１と同一である。比較例２は、骨材として天然珪砂１を用いた。その他は実施例２と同一である。比較例３は、骨材として天然珪砂１を用いた。その他は実施例３と同一である。比較例４は、骨材として天然珪砂２を用いた。その他は実施例１と同一である。比較例５は、骨材として天然珪砂２を用いた。その他は実施例２と同一である。比較例６は、骨材として天然珪砂２を用いた。その他は実施例３と同一である。 (Comparative Examples 1 to 6)
In Comparative Example 1, natural silica sand 1 was used as the aggregate. The rest was the same as in Example 1. In Comparative Example 2, natural silica sand 1 was used as the aggregate. The rest was the same as in Example 2. In Comparative Example 3, natural silica sand 1 was used as the aggregate. The rest was the same as in Example 3. In Comparative Example 4, natural silica sand 2 was used as the aggregate. The rest was the same as in Example 1. In Comparative Example 5, natural silica sand 2 was used as the aggregate. The rest was the same as in Example 2. In Comparative Example 6, natural silica sand 2 was used as the aggregate. The rest was the same as in Example 3.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１～６及び比較例１～６から１０ｍｍ×１０ｍｍ×１４０ｍｍの砂試験片を作製し、曲げ強度を測定した。曲げ強度の測定はＪＡＣＴ試験法ＳＭ－１、曲げ強さ試験法に準拠して行った。結果を図２に示す。 Sand test pieces measuring 10 mm x 10 mm x 140 mm were prepared from Examples 1 to 6 and Comparative Examples 1 to 6, and their bending strength was measured. The bending strength was measured in accordance with JACT test method SM-1, bending strength test method. The results are shown in Figure 2.
　図２は、各骨材における粘結剤の添加量と曲げ強度との関係を示すグラフである。図２は、横軸が粘結剤の添加量（重量部）であり、縦軸が曲げ強度（ＭＰａ）である。鋳造に用いられる中子は、輸送時や中子納め時に破損しない程度の強度が要求される。このため、曲げ強度３ＭＰａ以上を必要な強度として設定し、測定結果を評価した。図中の破線は回帰曲線である。図２に示されるように、実施例１～３の人工砂１の場合には、粘結剤が１重量部のときに曲げ強度３ＭＰａ以上を達成していることが確認された。実施例４～６の人工砂２の場合には、粘結剤が４重量部のときに曲げ強度３ＭＰａ以上を達成していることが確認された（回帰曲線から見積もると約２．５重量部）。これに対して、比較例１～３の天然珪砂１の場合には、粘結剤が４重量部（回帰曲線から見積もると約３．５重量部）のときに曲げ強度３ＭＰａ以上を達成しているものの、実施例４～６の人工砂２よりも曲げ強度が小さいことが確認された。比較例４～６の天然珪砂２の場合には、粘結剤が４重量部のときでも曲げ強度３ＭＰａ以上を達成できなかった。比較例４～６の天然珪砂２においては、曲げ強度３ＭＰａ以上を達成するためには、回帰曲線から見積もると粘結剤が５．０重量部必要と考えられる。このように、骨材として人工砂を採用することにより、天然珪砂と比べて少ない量の粘結剤で強度を確保できることが確認された。このような測定結果の差は、人工砂と天然珪砂との形状の違い、比表面積の違いが影響していると考えられる。人工砂は表面が滑らかで、天然珪砂は表面に凹凸が多いため、人工砂の方が比表面積は小さく、使用する粘結剤の量が少なくても所望の強度を得ることができると考えられる。 Figure 2 is a graph showing the relationship between the amount of binder added for each aggregate and bending strength. In Figure 2, the horizontal axis is the amount of binder added (parts by weight) and the vertical axis is bending strength (MPa). Cores used in casting are required to be strong enough not to break during transportation or when the cores are placed in place. For this reason, a bending strength of 3 MPa or more was set as the required strength, and the measurement results were evaluated. The dashed line in the figure is a regression curve. As shown in Figure 2, in the case of artificial sand 1 in Examples 1 to 3, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 1 part by weight. In the case of artificial sand 2 in Examples 4 to 6, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 4 parts by weight (approximately 2.5 parts by weight estimated from the regression curve). In contrast, in the case of the natural silica sand 1 of Comparative Examples 1 to 3, a bending strength of 3 MPa or more was achieved when the binder was 4 parts by weight (approximately 3.5 parts by weight estimated from the regression curve), but it was confirmed that the bending strength was smaller than that of the artificial sand 2 of Examples 4 to 6. In the case of the natural silica sand 2 of Comparative Examples 4 to 6, a bending strength of 3 MPa or more could not be achieved even when the binder was 4 parts by weight. In the case of the natural silica sand 2 of Comparative Examples 4 to 6, it is considered that 5.0 parts by weight of the binder is required to achieve a bending strength of 3 MPa or more, based on the estimation from the regression curve. In this way, it was confirmed that by using artificial sand as aggregate, strength can be ensured with a smaller amount of binder than natural silica sand. It is considered that such a difference in the measurement results is influenced by the difference in shape and specific surface area between the artificial sand and the natural silica sand. Since the artificial sand has a smooth surface and the natural silica sand has many irregularities on the surface, the artificial sand has a smaller specific surface area, and it is considered that the desired strength can be obtained even with a smaller amount of binder used.
［試験２：鋳型強度評価］
　粘結剤の種類、及び、粘結剤の添加量を変化させた実施例を製造し、鋳型強度を評価した。 [Test 2: Mold strength evaluation]
Examples were produced in which the type of binder and the amount of binder added were changed, and the mold strength was evaluated.
（粘結剤の種類）
　粘結剤としてモル比の異なるケイ酸ナトリウム及びケイ酸カリウムを用意した。
Figure JPOXMLDOC01-appb-T000003
 (Type of binder)
As a binder, sodium silicate and potassium silicate having different molar ratios were prepared.
Figure JPOXMLDOC01-appb-T000003
（骨材、界面活性剤）
　骨材は表１の人工砂１とし、界面活性剤はアニオン界面活性剤とした。 (aggregate, surfactant)
The aggregate was artificial sand 1 in Table 1, and the surfactant was an anionic surfactant.
（実施例７）
　骨材として人工砂１を用いた。人工砂１を１００重量部、粘結剤１を１重量部、界面活性剤を０．２５重量部とした。作製条件は実施例１と同一である。 (Example 7)
The aggregate used was artificial sand 1. The artificial sand 1 was 100 parts by weight, the binder 1 was 1 part by weight, and the surfactant was 0.25 parts by weight. The preparation conditions were the same as those in Example 1.
（実施例８～１８）
　実施例８、９は、粘結剤１を２重量部、４重量部とした。その他は実施例７と同一である。実施例１０～１２は、粘結剤２を１、２、４重量部とした。その他は実施例７と同一である。実施例１３～１５は、粘結剤３を１、２、４重量部とした。その他は実施例７と同一である。実施例１６～１８は、粘結剤４を１、２、４重量部とした。その他は実施例７と同一である。
Figure JPOXMLDOC01-appb-T000004
 (Examples 8 to 18)
In Examples 8 and 9, the amount of binder 1 was 2 parts by weight and 4 parts by weight. The rest was the same as Example 7. In Examples 10 to 12, the amount of binder 2 was 1, 2, and 4 parts by weight. The rest was the same as Example 7. In Examples 13 to 15, the amount of binder 3 was 1, 2, and 4 parts by weight. The rest was the same as Example 7. In Examples 16 to 18, the amount of binder 4 was 1, 2, and 4 parts by weight. The rest was the same as Example 7.
Figure JPOXMLDOC01-appb-T000004
　実施例７～１８から１０ｍｍ×１０ｍｍ×１４０ｍｍの砂試験片を作製し、曲げ強度を測定した。曲げ強度の測定はＪＡＣＴ試験法ＳＭ－１、曲げ強さ試験法に準拠して行った。結果を図３に示す。 Sand test pieces measuring 10 mm x 10 mm x 140 mm were prepared from Examples 7 to 18, and their bending strength was measured. The bending strength was measured in accordance with JACT test method SM-1, bending strength test method. The results are shown in Figure 3.
　図３は、各粘結剤の添加量と曲げ強度との関係を示すグラフである。図３は、横軸が粘結剤の添加量（重量部）であり、縦軸が曲げ強度（ＭＰａ）である。試験１と同様に、曲げ強度３ＭＰａ以上を必要な強度として設定し、測定結果を評価した。図中の破線は回帰曲線である。図３に示されるように、実施例７～９（実施例１～３）の粘結剤１の場合には、粘結剤が１重量部のときに曲げ強度３ＭＰａ以上を達成していることが確認された。実施例１０～１２の粘結剤２の場合には、粘結剤が４重量部（回帰曲線から見積もると約２．５重量部）のときに曲げ強度３ＭＰａ以上を達成していることが確認された。実施例１３～１５の粘結剤３の場合には、粘結剤が２重量部（回帰曲線から見積もると約１．５重量部）のときに曲げ強度３ＭＰａ以上を達成していることが確認された。実施例１６～１８の粘結剤４の場合には、粘結剤が４重量部のときに曲げ強度３ＭＰａ以上を達成していることが確認された。このように、粘結剤が１～４重量部のときに、曲げ強度３ＭＰａ以上を達成していることが確認された。さらに、何れの粘結剤においても、少なくとも４重量部あれば曲げ強度３ＭＰａ以上を達成することが確認された。 Figure 3 is a graph showing the relationship between the amount of each binder added and the bending strength. In Figure 3, the horizontal axis is the amount of binder added (parts by weight) and the vertical axis is the bending strength (MPa). As in Test 1, a bending strength of 3 MPa or more was set as the required strength, and the measurement results were evaluated. The dashed line in the figure is a regression curve. As shown in Figure 3, in the case of binder 1 in Examples 7 to 9 (Examples 1 to 3), it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 1 part by weight. In the case of binder 2 in Examples 10 to 12, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 4 parts by weight (approximately 2.5 parts by weight estimated from the regression curve). In the case of binder 3 in Examples 13 to 15, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 2 parts by weight (approximately 1.5 parts by weight estimated from the regression curve). In the case of binder 4 in Examples 16 to 18, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 4 parts by weight. In this way, it was confirmed that a bending strength of 3 MPa or more was achieved when the binder was 1 to 4 parts by weight. Furthermore, it was confirmed that with any binder, a bending strength of 3 MPa or more was achieved with at least 4 parts by weight.
［試験３：崩壊性評価］
　各骨材を用いて作製された鋳型（中子、主型）の崩壊性を評価した。 [Test 3: Evaluation of disintegration]
The collapsibility of the molds (core, main mold) made using each aggregate was evaluated.
　試験１の結果から見積もられた、曲げ強度３ＭＰａ以上を達成するために必要な粘結剤１の重量部を表５に示す。
Figure JPOXMLDOC01-appb-T000005
 The parts by weight of binder 1 required to achieve a bending strength of 3 MPa or more, estimated from the results of Test 1, is shown in Table 5.
Figure JPOXMLDOC01-appb-T000005
＜中子＞
（実施例１９，２０、比較例７，８）
　実施例１９においては、人工砂１を１００重量部、粘結剤１を１重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。実施例２０においては、人工砂２を１００重量部、粘結剤１を２．５重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。比較例７においては、天然珪砂１を１００重量部、粘結剤１を３．５重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。比較例８においては、天然珪砂２を１００重量部、粘結剤１を５．０重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。実施例１９，２０及び比較例７，８の作製条件は実施例１と同一であり、１０ｍｍ×１０ｍｍ×１４０ｍｍの中子が得られた。 <Middle part>
(Examples 19 and 20, Comparative Examples 7 and 8)
In Example 19, a core was prepared from 100 parts by weight of artificial sand 1, 1 part by weight of binder 1, and 0.25 parts by weight of anionic surfactant. In Example 20, a core was prepared from 100 parts by weight of artificial sand 2, 2.5 parts by weight of binder 1, and 0.25 parts by weight of anionic surfactant. In Comparative Example 7, a core was prepared from 100 parts by weight of natural silica sand 1, 3.5 parts by weight of binder 1, and 0.25 parts by weight of anionic surfactant. In Comparative Example 8, a core was prepared from 100 parts by weight of natural silica sand 2, 5.0 parts by weight of binder 1, and 0.25 parts by weight of anionic surfactant. The preparation conditions for Examples 19 and 20 and Comparative Examples 7 and 8 were the same as those for Example 1, and a core measuring 10 mm x 10 mm x 140 mm was obtained.
＜主型＞
（実施例２１）
　人工砂１を１００重量部、粘結剤１を１重量部とした材料を、混練機（卓上ミキサ：愛工舎製作所）を用いて約２００ｒｐｍで約５分間混合させて、湿態の混練砂を調整した。次いで、この混練砂を木型に手込めで充填した。３０ｍｍ×３０ｍｍ×１００ｍｍの鋳物を鋳造でき、１０ｍｍ×１０ｍｍ×１４０ｍｍの中子を収められる主型を造型できる木型を使用した。この木型に充填した混練砂に二酸化炭素（ＣＯ２）を３０秒間吹き込み、固化させた。固化完了後、木型から主型を取り出した。 <Main type>
(Example 21)
100 parts by weight of artificial sand 1 and 1 part by weight of binder 1 were mixed for about 5 minutes at about 200 rpm using a mixer (tabletop mixer: Aikosha Seisakusho) to prepare wet mixed sand. This mixed sand was then manually filled into a wooden mold. A wooden mold capable of casting a 30 mm x 30 mm x 100 mm casting and molding a master mold capable of housing a 10 mm x 10 mm x 140 mm core was used. Carbon dioxide ( CO2 ) was blown into the mixed sand filled into the wooden mold for 30 seconds to solidify it. After solidification was complete, the master mold was removed from the wooden mold.
（実施例２２、比較例９，１０）
　実施例２２においては、人工砂２を１００重量部、粘結剤１を２．５重量部で主型を作製した。比較例９においては、天然珪砂１を１００重量部、粘結剤１を３．５重量部で主型を作製した。比較例１０においては、天然珪砂２を１００重量部、粘結剤１を５．０重量部で主型を作製した。実施例２２及び比較例９，１０の作製条件は実施例２１と同一である。 (Example 22, Comparative Examples 9 and 10)
In Example 22, the master mold was made with 100 parts by weight of artificial sand 2 and 2.5 parts by weight of binder 1. In Comparative Example 9, the master mold was made with 100 parts by weight of natural silica sand 1 and 3.5 parts by weight of binder 1. In Comparative Example 10, the master mold was made with 100 parts by weight of natural silica sand 2 and 5.0 parts by weight of binder 1. The production conditions for Example 22 and Comparative Examples 9 and 10 are the same as those for Example 21.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　鋳造番号１における中子及び主型を用いて鋳鉄ＦＣ２００を鋳造した。中子及び主型への塗型をすることなく鋳造した。鋳造後、鋳物からの砂落としのために、湯口部をハンマーで１０回叩き、中子の崩壊の有無を目視で確認するとともに、鋳物に付着した砂の重量を測定した。鋳造番号２～４についても同一条件で中子の崩壊の有無を目視で確認するとともに、鋳物に付着した砂の重量を測定した。 Cast iron FC200 was cast using the core and main mold in casting number 1. Casting was performed without coating the core and main mold. After casting, the sprue was struck 10 times with a hammer to remove sand from the casting, and the core was visually inspected for collapse and the weight of sand adhering to the casting was measured. For casting numbers 2 to 4, the core was visually inspected for collapse under the same conditions and the weight of sand adhering to the casting was measured.
＜中子の崩壊性の目視結果＞
　鋳造番号１，２の人工砂では中子が崩壊し、中子の部分が貫通穴となった。これに対して、鋳造番号３，４の天然珪砂では中子が崩壊せず、鋳物の中に残った。このように、天然珪砂を骨材とした場合、中子の強度と崩壊性とを両立させることが困難であることが確認された。また、人工砂を骨材とすることで、中子の強度と崩壊性とを両立できることが確認された。 <Visual inspection results of core collapse>
In the artificial sand castings Nos. 1 and 2, the core collapsed, leaving a through hole in the core area. In contrast, in the natural silica sand castings Nos. 3 and 4, the core did not collapse and remained in the casting. Thus, it was confirmed that it is difficult to achieve both strength and collapsibility of the core when natural silica sand is used as aggregate. It was also confirmed that it is possible to achieve both strength and collapsibility of the core by using artificial sand as aggregate.
＜鋳物に付着した砂＞
　図４は、各骨材における砂落とし後の鋳肌への砂残量を示すグラフである。横軸は鋳造番号、縦軸は砂残量である。図４に示されるように、骨材が人工砂である鋳造番号１では砂残量は２ｇ程度であり、同じく骨材が人工砂である鋳造番号２では砂残量は６ｇ程度であった。このように、骨材が人工砂である場合には、砂は鋳物にわずかに付着する程度であった。これに対して、骨材が天然珪砂である鋳造番号３では砂残量は３６ｇ程度であり、同じく骨材が天然珪砂である鋳造番号４では砂残量は３２ｇ程度であった。そして、鋳物を取り囲むように天然珪砂が固まっていた。なお、天然珪砂は焼付き欠陥が生じたため、金属やすりで鋳物から除去できた天然珪砂の重量を計測した。このように、天然珪砂を骨材とした場合、主型の強度と崩壊性とを両立させることが困難であることが確認された。また、人工砂を骨材とすることで、主型の強度と崩壊性とを両立できることが確認された。 <Sand adhering to castings>
FIG. 4 is a graph showing the amount of sand remaining on the casting surface after sand removal for each aggregate. The horizontal axis is the casting number, and the vertical axis is the amount of remaining sand. As shown in FIG. 4, the amount of remaining sand was about 2 g in casting No. 1, where the aggregate was artificial sand, and about 6 g in casting No. 2, where the aggregate was artificial sand. Thus, when the aggregate was artificial sand, the sand only adhered slightly to the casting. In contrast, the amount of remaining sand was about 36 g in casting No. 3, where the aggregate was natural silica sand, and about 32 g in casting No. 4, where the aggregate was natural silica sand. The natural silica sand was hardened to surround the casting. Since the natural silica sand caused a seizure defect, the weight of the natural silica sand that could be removed from the casting with a metal file was measured. Thus, it was confirmed that it is difficult to achieve both strength and collapsibility of the main mold when natural silica sand is used as the aggregate. It was also confirmed that it is possible to achieve both strength and collapsibility of the main mold by using artificial sand as the aggregate.
［試験４：崩壊性評価］
　各粘結剤を用いて作製された中子及び主型の崩壊性を評価した。 [Test 4: Evaluation of disintegration]
The collapsibility of the core and the main mold made using each binder was evaluated.
　試験２の結果から見積もられた、人工砂１における曲げ強度３ＭＰａ以上を達成するために必要な各粘結剤の重量部を表７に示す。
Figure JPOXMLDOC01-appb-T000007
 Table 7 shows the parts by weight of each binder required to achieve a bending strength of 3 MPa or more in artificial sand 1, which was estimated from the results of Test 2.
Figure JPOXMLDOC01-appb-T000007
＜中子＞
（実施例２３～２６）
　実施例２３においては、人工砂１を１００重量部、粘結剤１を１重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。実施例２４においては、人工砂１を１００重量部、粘結剤２を２．５重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。実施例２５においては、人工砂１を１００重量部、粘結剤３を１．５重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。実施例２６においては、人工砂１を１００重量部、粘結剤４を４．０重量部、アニオン界面活性剤を０．２５重量部で中子を作製した。実施例２３～２６の作製条件は実施例１と同一である。 <Middle part>
(Examples 23 to 26)
In Example 23, a core was made with 100 parts by weight of artificial sand 1, 1 part by weight of binder 1, and 0.25 parts by weight of anionic surfactant. In Example 24, a core was made with 100 parts by weight of artificial sand 1, 2.5 parts by weight of binder 2, and 0.25 parts by weight of anionic surfactant. In Example 25, a core was made with 100 parts by weight of artificial sand 1, 1.5 parts by weight of binder 3, and 0.25 parts by weight of anionic surfactant. In Example 26, a core was made with 100 parts by weight of artificial sand 1, 4.0 parts by weight of binder 4, and 0.25 parts by weight of anionic surfactant. The preparation conditions for Examples 23 to 26 were the same as those for Example 1.
＜主型＞
（実施例２７～３０）
　実施例２７においては、人工砂１を１００重量部、粘結剤１を１重量部で主型を作製した。実施例２８においては、人工砂１を１００重量部、粘結剤２を２．５重量部で主型を作製した。実施例２９においては、人工砂１を１００重量部、粘結剤３を１．５重量部で主型を作製した。実施例３０においては、人工砂１を１００重量部、粘結剤４を４．０重量部で主型を作製した。実施例２７～３０の作製条件は実施例２１と同一である。 <Main type>
(Examples 27 to 30)
In Example 27, the master mold was made with 100 parts by weight of artificial sand 1 and 1 part by weight of binder 1. In Example 28, the master mold was made with 100 parts by weight of artificial sand 1 and 2.5 parts by weight of binder 2. In Example 29, the master mold was made with 100 parts by weight of artificial sand 1 and 1.5 parts by weight of binder 3. In Example 30, the master mold was made with 100 parts by weight of artificial sand 1 and 4.0 parts by weight of binder 4. The production conditions for Examples 27 to 30 were the same as those for Example 21.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　鋳造番号５における中子及び主型を用いて鋳鉄ＦＣ２００を鋳造した。中子及び主型への塗型をすることなく鋳造した。鋳造後、鋳物からの砂落としのために、湯口部をハンマーで１０回叩き、中子の崩壊の有無を目視で確認するとともに、鋳物に付着した砂の重量を測定した。鋳造番号６～８についても同一条件で中子の崩壊の有無を目視で確認するとともに、鋳物に付着した砂の重量を測定した。 Cast iron FC200 was cast using the core and main mold in casting number 5. Casting was performed without coating the core and main mold. After casting, the sprue was struck 10 times with a hammer to remove sand from the casting, and the core was visually inspected for collapse and the weight of sand adhering to the casting was measured. For casting numbers 6 to 8, the core was visually inspected for collapse under the same conditions and the weight of sand adhering to the casting was measured.
＜中子の崩壊性の目視結果＞
　鋳造番号５～８の人工砂では中子が崩壊し、中子の部分が貫通穴となった。このように、粘結剤の種類に関わらず、人工砂を骨材とすることで、中子の強度と崩壊性とを両立できることが確認された。 <Visual inspection results of core collapse>
The core collapsed and a through hole was formed in the artificial sand of casting numbers 5 to 8. In this way, it was confirmed that by using artificial sand as aggregate, regardless of the type of binder, it is possible to achieve both strength and collapse property of the core.
＜鋳物に付着した砂＞
　図５は、各粘結剤における砂落とし後の鋳肌への砂残量を示すグラフである。横軸は鋳造番号、縦軸は砂残量である。図５に示されるように、骨材が人工砂である鋳造番号５～８では砂残量は何れも４ｇ以下であり、粘結剤の種類に関わらず、骨材が人工砂である場合には、砂は鋳物にわずかに付着する程度であることが確認された。また、粘結剤の種類に関わらず、人工砂を骨材とすることで、主型の強度と崩壊性とを両立できることが確認された。 <Sand adhering to castings>
Figure 5 is a graph showing the amount of sand remaining on the casting surface after sand removal for each binder. The horizontal axis is the casting number, and the vertical axis is the amount of remaining sand. As shown in Figure 5, the amount of remaining sand was 4g or less for casting numbers 5 to 8, in which the aggregate was artificial sand, and it was confirmed that, regardless of the type of binder, when the aggregate was artificial sand, only a small amount of sand adhered to the casting. It was also confirmed that, regardless of the type of binder, by using artificial sand as the aggregate, it was possible to achieve both strength and collapsibility of the main mold.
　以上、例示的実施形態について説明してきたが、上述した例示的実施形態に限定されることなく、様々な省略、置換、及び変更がなされてもよい。 Although exemplary embodiments have been described above, various omissions, substitutions, and modifications may be made without being limited to the exemplary embodiments described above.
　本開示に含まれる種々の例示的実施形態は以下の条項を含む。
［条項１］
　鉄系鋳物を製造する鋳型を造型する鋳型造型方法であって、
　骨材である人工砂と粘結剤とを用いて混練砂を生成するステップと、
　前記混練砂を型に充填するステップと、
　前記型に充填された前記混練砂を固化させるステップと、
を含む鋳型造型方法。
［条項２］
　前記人工砂は、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下であり、前記粘結剤は、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方である、条項１に記載の鋳型造型方法。
［条項３］
　前記粘結剤はモル比が１．８以上である、条項１又は２に記載の鋳型造型方法。
［条項４］
　前記粘結剤は前記骨材１００重量部に対して４重量部以下である、条項１～３の何れか一項に記載の鋳型造型方法。
［条項５］
　前記人工砂は、溶融法又は焼結法により製造される、条項１～４の何れか一項に記載の鋳型造型方法。
［条項６］
　前記固化させるステップでは、脱水縮合反応によって前記混練砂を固化させる、条項１～５の何れか一項に記載の鋳型造型方法。
［条項７］
　前記固化させるステップでは、二酸化炭素（ＣＯ２）ガスを用いて前記混練砂を固化させる、条項１～６の何れか一項に記載の鋳型造型方法。
［条項８］
　　前記混練砂は、界面活性剤を含む発泡混練砂である、条項１～７の何れか一項に記載の鋳型造型方法。
［条項９］
　鉄系鋳物を製造する鋳型の鋳型材料であって、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下である人工砂を骨材とし、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方を粘結剤として含む、鋳型材料。 Various exemplary embodiments included in this disclosure include the following provisions:
[Clause 1]
A mold making method for making a mold for producing an iron-based casting, comprising the steps of:
A step of producing mixed sand using artificial sand as aggregate and a binder;
Filling the mixed sand into a mold;
A step of solidifying the mixed sand filled in the mold;
A mold making method comprising:
[Clause 2]
2. The mold-making method according to claim 1, wherein the artificial sand contains 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ), and the binder is one of sodium silicate and potassium silicate.
[Clause 3]
3. The method for making a mold according to claim 1 or 2, wherein the binder has a molar ratio of 1.8 or more.
[Clause 4]
The mold-making method according to any one of claims 1 to 3, wherein the binder is 4 parts by weight or less per 100 parts by weight of the aggregate.
[Clause 5]
5. The mold-making method according to any one of claims 1 to 4, wherein the artificial sand is produced by a melting method or a sintering method.
[Clause 6]
The mold making method according to any one of clauses 1 to 5, wherein in the solidifying step, the mixed sand is solidified by a dehydration condensation reaction.
[Clause 7]
7. The mold making method according to any one of clauses 1 to 6, wherein in the solidifying step, the mixed sand is solidified using carbon dioxide (CO 2 ) gas.
[Clause 8]
8. The mold-making method according to any one of claims 1 to 7, wherein the mixed sand is a foamed mixed sand containing a surfactant.
[Clause 9]
A mold material for a mold for producing iron-based castings, comprising artificial sand containing 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ) as aggregate, and containing either sodium silicate or potassium silicate as a binder.

Claims (9)

  1. 　鉄系鋳物を製造する鋳型を造型する鋳型造型方法であって、
    　骨材である人工砂と粘結剤とを用いて混練砂を生成するステップと、
    　前記混練砂を型に充填するステップと、
    　前記型に充填された前記混練砂を固化させるステップと、
    を含む鋳型造型方法。     A mold making method for making a mold for producing an iron-based casting, comprising the steps of:
    A step of producing mixed sand using artificial sand as aggregate and a binder;
    Filling the mixed sand into a mold;
    A step of solidifying the mixed sand filled in the mold;
    A mold making method comprising:
  2. 　前記人工砂は、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下であり、
    　前記粘結剤は、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方である、請求項１に記載の鋳型造型方法。     The artificial sand contains 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 );
    2. The method for making a mold according to claim 1, wherein the binder is one of sodium silicate and potassium silicate.
  3. 　前記粘結剤はモル比が１．８以上である、請求項１又は２に記載の鋳型造型方法。 The mold making method according to claim 1 or 2, wherein the binder has a molar ratio of 1.8 or more.
  4. 　前記粘結剤は前記骨材１００重量部に対して４重量部以下である、請求項１又は２に記載の鋳型造型方法。 The mold making method according to claim 1 or 2, wherein the binder is 4 parts by weight or less per 100 parts by weight of the aggregate.
  5. 　前記人工砂は、溶融法又は焼結法により製造される、請求項１又は２に記載の鋳型造型方法。 The mold-making method according to claim 1 or 2, wherein the artificial sand is produced by a melting method or a sintering method.
  6. 　前記固化させるステップでは、脱水縮合反応によって前記混練砂を固化させる、請求項１又は２に記載の鋳型造型方法。 The mold making method according to claim 1 or 2, wherein in the solidifying step, the mixed sand is solidified by a dehydration condensation reaction.
  7. 　前記固化させるステップでは、二酸化炭素（ＣＯ２）ガスを用いて前記混練砂を固化させる、請求項１又は２に記載の鋳型造型方法。 The mold making method according to claim 1 or 2, wherein the mixed sand is solidified using carbon dioxide (CO 2 ) gas in the solidifying step.
  8. 　前記混練砂は、少なくとも界面活性剤を含む発泡混練砂である、請求項１又は２に記載の鋳型造型方法。 The mold-making method according to claim 1 or 2, wherein the mixed sand is expanded mixed sand containing at least a surfactant.
  9. 　鉄系鋳物を製造する鋳型の鋳型材料であって、酸化アルミニウム（Ａｌ２Ｏ３）が６０％以上、かつ、二酸化ケイ素（ＳｉＯ２）が４０％以下である人工砂を骨材とし、ケイ酸ナトリウム及びケイ酸カリウムの何れか一方を粘結剤として含む、鋳型材料。 A mold material for a mold for producing iron-based castings, comprising artificial sand containing 60% or more aluminum oxide (Al 2 O 3 ) and 40% or less silicon dioxide (SiO 2 ) as aggregate, and containing either sodium silicate or potassium silicate as a binder.
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JP2014527915A (en) * 2011-09-30 2014-10-23 エーエスケー ケミカルズ ゲゼルシャフト ミット ベシュレンクテル ハフツング COATING COMPOSITION FOR INORGANIC MOLD AND CORE AND METHOD OF USING THE SAME
JP2018047493A (en) * 2016-09-23 2018-03-29 トヨタ自動車株式会社 Molding method of core
JP2019111577A (en) * 2017-12-26 2019-07-11 花王株式会社 Particle for molding mold
JP2020011296A (en) * 2018-07-09 2020-01-23 花王株式会社 Inorganic coated sand

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WO2014098129A1 (en) * 2012-12-19 2014-06-26 旭有機材工業株式会社 Coated sand, manufacturing method for same, and manufacturing method for mold
JP2018047493A (en) * 2016-09-23 2018-03-29 トヨタ自動車株式会社 Molding method of core
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