STRUCTURE FOR PRODUCING CASTING

Abstract

A cylindrical structure for producing a casting can comprise: a cylindrical main body having a body part and a female joint consecutively connected to the body part and having an inner diameter larger than an outer diameter of the body part. A body inside cover layer can cover the inner face of the body part and/or an outside cover layer can cover an outer face of the female joint

Description

SUMMARY

The present disclosure may be regarded as relating to a cylindrical structure for producing a casting.

In one embodiment, a cylindrical main body can be provided which has a body part and a female joint consecutively connected to the body part and having an inner diameter equal to or larger than the outer diameter of the body part.

A body inside cover layer can cover the inner face of the body part and/or an outside cover layer can cover the outer face of the female joint.

In one embodiment, a cylindrical main body can be provided which has a body part, and a male joint, which is to be internally joined to the female joint, in one end part of the body part.

In one embodiment, the male joint can have an outer diameter equal to or smaller than the inner diameter of the female joint.

A body inside cover layer can cover the inner face of the body part and/or an outside cover layer can cover the outer face of the male joint.

One or more embodiments of the present disclosure may also be regarded as relating to a method for producing a cylindrical structure for producing a casting.

In one aspect, the structure for producing a casting can have a cylindrical main body having a body part and a female joint consecutively connected to the body part and having an inner diameter equal to or larger than the outer diameter of the body part.

In one aspect, a body part applying step can be implemented where a coating composition is applied to the inner face of the body part to form a body inside cover layer covering the inner face of the body part.

In one aspect, a female joint applying step can be implemented where a coating composition is applied to the outer face of the female joint over the entire circumference of the female joint to form an outside cover layer covering the outer face of the female joint.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view schematically showing a structure for producing a casting according to one or more embodiments of the present disclosure.

FIG. 2 (a) is a IIa-IIa line cross-sectional view of FIG. 1, FIG. 2 (b) is a IIb-IIb line cross-sectional view of FIG. 1, and FIG. 2 (c) is a IIc-IIc line cross-sectional view of FIG. 1.

FIG. 3 is a perspective view schematically showing a state in which the structures for producing a casting shown in FIG. 1 are coupled to each other according to one or more embodiments of the present disclosure.

FIG. 4 is enlarged cross-sectional view of a part of FIG. 3.

FIG. 5 is a schematic cross-sectional view of a mold housing the structure for producing a casting shown in FIG. 1 inside.

FIG. 6 (a) is a cross-sectional view schematically showing another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 2 (a). FIG. 6 (b) is an enlarged cross-sectional view of a part schematically showing a state in which the structures for producing a casting shown in FIG. 6 (a) are coupled to each other, and is a view equivalent to FIG. 4, according to one or more embodiments of the present disclosure.

FIG. 7 (a) is a cross-sectional view schematically showing a yet another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 2 (a). FIG. 7 (b) is an enlarged cross-sectional view of a part schematically showing a state in which the structures for producing a casting shown in FIG. 7 (a) are coupled to each other, and is a view equivalent to FIG. 4, according to one or more embodiments of the present disclosure.

FIG. 8 (a) is a cross-sectional view schematically showing a yet another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 2 (a). FIG. 8 (b) is an enlarged cross-sectional view of a part schematically showing a state in which the structures for producing a casting shown in FIG. 8 (a) are coupled to each other, and is a view equivalent to FIG. 4, according to one or more embodiments of the present disclosure.

FIG. 9 (a) is a cross-sectional view schematically showing a yet another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 2 (a). FIG. 9 (b) is an enlarged cross-sectional view of a principal part schematically showing a state in which the structures for producing a casting shown in FIG. 9 (a) are coupled to each other, and is a view equivalent to FIG. 4, according to one or more embodiments of the present disclosure.

FIG. 10 (a) is a cross-sectional view schematically showing a yet another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 2 (a). FIG. 10 (b) is an enlarged cross-sectional view of a principal part schematically showing a state in which the structures for producing a casting shown in FIG. 9 (a) are coupled to each other, and is a view equivalent to FIG. 4, according to one or more embodiments of the present disclosure.

FIG. 11 is an enlarged cross-sectional view of a part schematically showing another embodiment of the structure for producing a casting according to the present disclosure.

FIG. 12 is a perspective view schematically showing another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 1, according to one or more embodiments of the present disclosure.

FIG. 13 (a) is a XIIIa-XIIIa line cross-sectional view of FIG. 12, and FIG. 13 (b) is a XIIIb-XIIIb line cross-sectional view of FIG. 12.

FIG. 14 is a perspective view schematically showing a state in which the structures for producing a casting shown in FIG. 12 are coupled to each other, and is a view equivalent to FIG. 3, according to one or more embodiments of the present disclosure.

FIG. 15 is an enlarged cross-sectional view of a part of FIG. 14.

FIG. 16 (a) is a cross-sectional view schematically showing a yet another embodiment of the structure for producing a casting according to the present disclosure, and is a view equivalent to FIG. 13 (a). FIG. 16 (b) is an enlarged cross-sectional view of a part schematically showing a state in which the structures for producing a casting shown in FIG. 16 (a) are coupled to each other, and is a view equivalent to FIG. 15, according to one or more embodiments of the present disclosure.

FIGS. 17 (a) to 17 (d) are perspective views schematically showing modifications of the structure for producing a casting according to one or more embodiments of the present disclosure, and is a view equivalent to FIG. 2 (a).

FIGS. 18 (a) to 18 (e) are schematic cross-sectional views explaining one or more aspects of a method for producing a structure for producing a casting according to one or more embodiments of the present disclosure.

FIGS. 19 (a) to 19 (e) are schematic cross-sectional views explaining modifications or variations of one or more aspects and/or one or more embodiments of the method for producing a structure for producing a casting according to the present disclosure.

DESCRIPTION OF EMBODIMENTS

The present disclosure relates to a structure for producing a casting, and systems, devices, and methods thereof.

In the production of castings, generally, a mold having a cavity inside may be formed using casting sand and a receiving port, a sprue, a runner, and a gate for supplying molten metal to the cavity are formed to communicate with the cavity, and further, a gas vent communicating with the outside, a riser, and a strain relief can be formed. Inside the cavity, a core may be arranged.

Convention structures for producing a casting may have room for improvement, for instance, in a possibility that the molten metal leaks to the outside of the structure for producing a casting when the pressure of the molten metal inside the structure for producing a casting is high in the pouring of the molten metal. The leakage of the molten metal may be particularly likely to occur in a portion where the adjacent structures for producing a casting are joined to each other.

Thus, one or more embodiments of present disclosure can be regarded as relating to a structure for producing a casting, and systems and methods thereof, for instance, capable of preventing the leakage of the molten metal in the pouring of the molten metal.

Hereinafter, the present disclosure describes one or more embodiments thereof.

FIG. 1 shows a structure for producing a casting (hereinafter also simply referred to as a “structure”) 1 according to a first embodiment of the structure for producing a casting of the present disclosure.

The structure 1, according to one or more embodiments, may be cylindrical, though embodiments of the present disclosure are not limited to a cylindrical configuration. The term “cylindrical” used herein can include a straight one, such as shown in FIG. 1, one having a bent part 17 in a part in the axial direction, such as shown in FIG. 17 (a), one in which the entirety in the axial direction is curved in an arc shape, such as shown in FIG. 17 (b), one having a cylindrical second part 19 branched from a cylindrical first part 18, such as shown in FIGS. 17 (c) and 17 (d), and/or the like. Further, the term “cylindrical” may include not only a cylindrical shape having a circular cross section, i.e., a circular cylindrical shape, but a cylindrical shape having a polygonal cross section, i.e., a square cylindrical shape. According to one or more embodiments, the cross-sectional shape orthogonal to the axial direction of a circular cylindrical structure may be a circular shape, and may also be an oval shape, as some examples. The cross-sectional shape orthogonal to the axial direction of a square cylindrical structure may be a square shape, and may also be a triangular shape, a rectangular shape, or a polygonal shape of a pentagonal shape or more or may be a shape in which the corners of the polygon are rounded, as additional examples.

The structure 1 can have a cylindrical main body 20. The main body 20 may contain organic fibers, inorganic fibers, inorganic particles, and a binder. The main body 20 can be regarded as a portion constituting a main part of the structure 1.

The main body 20 can have a body part 11 and a female joint 12 consecutively connected to the body part 11 and can have an inner diameter equal to or larger than the outer diameter of the body part 11. The female joint 12 may be formed at one end 1a in the axial direction of the body part 11. This example is shown in FIG. 2. In one example of the structure 1 shown in FIG. 2, the main body 20 can have the inner diameter larger on the one end 1a side in an axial direction Z than on the other end 1b side.

The female joint 12 may be formed to be branched from the body part 11. This example is shown in FIG. 17 (d). In one example of the structure 1 shown in FIG. 17 (d), the inner diameters of end parts 1c and 1d other than the female joint 12 in the structure 1 can be equal to or smaller than the inner diameter of the female joint 12. In one example of the structure 1 shown in FIG. 17 (d), the inner diameter of the end part 1c of the structure 1 and the inner diameter of the end part 1d of the structure 1 may be the same or different from each other. Optionally, only the inner diameter of any of the end part 1c and the end part 1d of the structure 1 may be equal to or smaller than the inner diameter of the female joint 12.

The female joint 12, according to one or more embodiments of the present disclosure, may have both the inner diameter and the outer diameter larger than those of the body part 11. In one example of the structure 1 shown in FIG. 2, an end part on the one end 1a side in the axial direction Z in the body part 11 can be formed with a step part 15 projecting outward in the radial direction of the body part 11, and the female joint 12 can be consecutively connected to the body part 11 via the step part 15.

As the structure 1, according to one or more embodiments, it may be that more than one structure of the same or a similar type can be coupled to each other.

In one example of the structure 1 shown in FIG. 1, both the ends in the axial direction Z in the main body 20 can be in an opened state.

An outer diameter D1 of an end part of the structure 1 other than the female joint 12 can be equal to or smaller than an inner diameter D2 of the female joint 12.

In one example of the structure 1 shown in FIGS. 1 and 2, the end part of the structure 1 other than the female joint 12 can refer to an end part on the other end 1b side opposite to the one end 1a in the axial direction Z in the body part 11.

In one example of the structure 1 shown in FIG. 17 (d), the end part of the structure 1 other than the female joint 12 can refer to the end parts 1c and 1d of a first part 18. When an outer diameter D11 of the end part 1c of the first part 18 is different from an outer diameter D12 of the end part 1d of the first part 18, the outer diameter D1 can be the smaller diameter of the outer diameter D11 and the outer diameter D12. Optionally, only one of the outer diameter D11 of the end part 1c of the first part 18 and the outer diameter D12 of the end part 1d of the first part 18 may be equal to or smaller than the inner diameter D2 of the female joint 12. Both the outer diameter D11 and the outer diameter D12 can be equal to or smaller than the inner diameter D2 of the female joint 12.

In the specification of the present application, the inner diameter and the outer diameter can mean the inner diameter and the outer diameter in the entire structure 1 including both the main body and cover layers covering the surfaces of the main body, unless otherwise particularly specified.

The structure 1 can be configured such that the structures 1 can be coupled to each other by inserting and joining the end part of the structure 1 other than the female joint 12 to the female joint 12 of the other structure 1. By coupling a desired number of the structures 1, a long cylindrical body 10 having a desired length can be formed (see e.g., FIG. 3).

The end part of the structure 1 other than the female joint 12 may serve as a male joint 13 internally joined to the female joint having an inner diameter equal to or larger than the outer diameter of the body part 11. In one example of the structure 1 shown in FIG. 17 (d), only one of the outer diameter D11 of the end part 1c of the first part 18 and the end part 1d of the first part 18 may serve as the male joint 13. Both the end part 1c and the end part 1d may serve as the male joints 13.

The male joint 13 can mean a portion inserted into the female joint 12 when the end part of the structure 1 other than the female joint 12 is internally joined to the female joint 12 of the structure 1 of the same type or a similar type. In detail, a length L1 of the male joint 13 can be the same as a length L2 of the female joint 12. Herein, the “same” can mean not only a case where the length L1 of the male joint 13 and the length L2 of the female joint 12 are the same, but a case where the length L1 and the length L2 are approximated to such an extent that the length L1 and the length L2 are assumed to be substantially equal to each other. Specifically, when a ratio of the length L1 of the male joint 13 to the depth L2 of the female joint 12 can be preferably 80% or more and 120% or less, more preferably 90% or more and 110% or less, and even more preferably 95% or more and 105% or less, the depth L2 and the length L1 can be assumed to be the same. Examples of the length L1 and the depth L2 are shown in FIGS. 2 (a) and 17 (d).

In one example of the structure 1 shown in FIG. 2, the length L1 of the male joint 13 can be the length of the male joint 13 along the axial direction Z of the body part 11. In one example of the structure 1 shown in FIG. 17 (d), the length L1 of the male joint 13 can be the length of the male joint 13 along an axial direction Zx of a first part 18.

In one example of the structure 1 shown in FIG. 2, a length L3 in the axial direction Z of the body part 11 can be longer than the depth L2 of the female joint 12. In one example of the structure 1 shown in FIG. 2, when the length L3 in the axial direction Z of the body part 11 is shorter than the depth L2 of the female joint 12 or when the length L3 of the body part 11 and the depth L2 of the female joint 12 are the same, the entire region of the body part 11 can substantially serve as the male joint 13.

The structure 1 can have a body inside cover layer 31 covering the inner face of the body part 11 and an outside cover layer 32 covering the outer face of the female joint 12 (hereinafter also referred to as the “outside cover layer of the female joint”). This example is shown in FIG. 2 (a).

According to one or more embodiments, the body inside cover layer 31 and the outside cover layer 32 can contain refractory inorganic particles selected from the group consisting of metal oxides and metal silicates, a binder, and clay minerals. Each component contained in both the cover layers 31 and 32 is described later.

The body inside cover layer 31 can be continuous over the entire circumference in the circumferential direction of the structure 1, according to one or more embodiments of the present disclosure. This example is shown in FIG. 2 (b).

Additionally or alternatively, the body inside cover layer 31 can be continuous over the entire region of the body part 11 in the axial direction Z. More specifically, the body inside cover layer 31 can cover the entire region of the inner face of the body part 11. This example is shown in FIG. 2 (a).

Due to the flow of high-temperature molten metal into the structure 1, gas can be generated from casting sand when the organic fibers, the binder, and the like contained in the main body 20 are thermally decomposed. The structure 1 can have the body inside cover layer 31, and therefore can prevent the entry of the gas into the structure 1. This can make it hard for the gas to get mixed into the molten metal flowing in the structure 1.

From the viewpoint of more remarkably exhibiting this effect, the body inside cover layer 31 can be continuous over the entire circumference in the circumferential direction of the structure 1 and optionally can cover the entire region of the inner face of the body part 11.

The outside cover layer 32 of the female joint 12 can be continuous over the entire circumference in the circumferential direction of the structure 1, according to one or more embodiments of the present disclosure. This example is shown in FIG. 2 (c).

Additionally or alternatively, the outside cover layer 32 can be continuous over the entire region of the outer face of the female joint 12 in the axial direction Z. More specifically, the outside cover layer 32 can cover the entire region of the outer face of the female joint 12. This example is shown in FIG. 2 (a).

The structure 1 can be used to produce a casting as follows, for example.

First, the structures 1 can be coupled to each other to form the cylindrical body 10. Then, as shown in FIG. 5, the cylindrical body 10 can be embedded in a predetermined position in casting sand to form a mold 40. In the example shown in FIG. 5, the mold 40 can be regarded as a sand mold. The structure 1 can be embedded leaving a part of opening parts. Specifically, the structure 1, which can be positioned on the most upstream side among the plurality of structures 1 coupled to each other to form the cylindrical body 10, can be embedded in a state where the opening part on the upstream side is exposed to the outside of the casting sand.

There may be no particular limitations on a method for embedding the cylindrical body 10; for example, the casting sand may be arranged after the cylindrical body 10 is arranged at a predetermined position or the cylindrical body 10 may be arranged after casting sand is arranged at a predetermined position.

For the casting sand of the sand mold 40, casting sand that has been conventionally used to produce the casting of this type can be used without limitations.

Then, molten metal can be poured into the mold 40 for casting. Specifically, the molten metal can be poured from a pouring hole 41 provided at one end of the cylindrical body 10, and the molten metal can be supplied into a cavity 42 for casting. At this time, the warm strength can be maintained and the heat shrinkage due to the thermal decomposition can be small in the structure 1. Therefore, cracks in each structure 1 and damage to the structure 1 itself can be suppressed, and the insertion of the molten metal into the structure 1 or the adhesion of the casting sand or the like to the structure 1 may also be hard to occur.

After the casting, the temperature can be reduced to a predetermined temperature, the casting sand can be removed by disassembling a flask, and the structure 1 for producing a casting can be removed through blasting treatment, exposing a casting. Thereafter, the casting can be subjected to post-treatment, such as trimming, as required, to complete the production of the casting.

The structure 1 can be suitably used as a runner or a strain relief runner used for casting, for example.

Further, the structure 1 can be particularly suitably used as a runner or a strain relief runner in the production of cast steel. This can be because the cast steel can have a melting point higher than that of cast iron, and therefore the temperature of the molten metal in the pouring of the molten metal can be high and the kinematic viscosity is likely to be lower.

The structure 1 can have the outside cover layer 32 of the female joint 12, and thus, for example, can prevent the leakage in the pouring of the molten metal. Hereinafter, this point is described in detail.

When the structures 1 are coupled to each other, it may be hard to bring an end face 11e of the end part other than the female joint 12 in one structure 1, i.e., the end face 11e of the male joint 13 of one structure 1, and an end face 12e arranged inside the female joint 12 of the other structure 1 into close contact with each other without any gaps. Therefore, a gap may sometimes be generated between the end face 11e of one structure 1 and the end face 12e of the other structure 1 (see FIG. 4). In the example shown in the figure, the end face 12e of the female joint 12 can be regarded as the upper surface 12e of the step part 15.

In the pouring of the molten metal, the molten metal entering the gap can come into contact with a corner part formed by an inner circumferential surface 12a of the female joint 12 and the upper surface 12e of the step part 15 (hereinafter also referred to as the “corner part of the female joint”). This can sometime damages the corner part, resulting in the generation of a pore passing through the female joint 12. The molten metal flowing in the structure 1 can have a risk of leaking to the outside of the structure 1 through such a pore.

However, by covering the outer face of the female joint 12 with the outside cover layer 32, the molten metal can be prevented from passing through the female joint 12 to leak out to the outside of the structure 1. The outside cover layer 32 can cover the outer face of the female joint 12 as described above, and therefore can pose no risk of peeling when the male joint 13 is joined to the female joint 12. Therefore, the effect of preventing the leakage of the molten metal can be surely exhibited. From the viewpoint of more effectively preventing the leakage of the molten metal, a female joint inside cover layer 33 covering the inner face of the female joint 12 can be provided in addition to the outside cover layer 32. The female joint inside cover layer 33 is described later.

In a case where the molten metal leaks to the outside of the structure 1, the molten metal can come into contact with the casting sand, which may result in metal penetration in which the casting sand is mixed into the molten metal. In general, when the casting is produced, a product portion formed by the solidification of the molten metal in the cavity of the sand mold and a portion other than the product formed by the solidification of the molten metal inside a runner pipe can be obtained. By suppressing the mixing of the casting sand into the molten metal, the portion other than product can be easily re-used. Further, a step for removing the casting sand from the molten metal obtained by remelting the portion other than the product can be omitted, and therefore the cost can be reduced, and the quality of the molten metal obtained by remelting the portion other than product can be stabilized.

The effect of preventing the leakage of the molten metal from the structure 1 in the pouring of the molten metal can be exhibited when an inner diameter D3 of the body part 11 in the structure 1 is large. In general, the leakage of the molten metal in the pouring of the molten metal may be likely to occur when the molten metal of the structure 1 has a high pressure. When the cavity 42 of the mold 40 used for the casting is large, the amount of the molten metal to be poured can become large. To prevent a decrease in the temperature of a large amount of the molten metal during the pouring of the molten metal, one, in which the inner diameter D3 of the body part 11 is large, capable of increasing the flow rate of the molten metal to be poured can be used as the structure 1 constituting the cylindrical body 10 embedded in the mold 40. When the cavity 42 is large, the mold 40 may also become large in connection therewith, and therefore the vertical height of the cylindrical body 10 may be likely to be large. Therefore, when the inner diameter D3 of the body part 11 in the structure 1 is large, the structure 1 can be used under a condition where the pressure of the molten metal is high in many cases. Specifically, when the inner diameter D3 of the other end part on the side opposite to the one end 1a side in the axial direction Z in the body part 11, i.e., the male joint 13, is 45 mm or more, for instance, it can be supposed that the structure 1 can be used under a condition where the molten metal has a high pressure.

The structure 1 according to one or more embodiments of the present disclosure can prevent the leakage of the molten metal in the pouring of the molten metal, even when the inner diameter D3 of the body part 11 in the structure 1 is large and the pressure of the molten metal in the body part 11 is high. From the viewpoint of more remarkably exhibiting the effect of being able to prevent the leakage of the molten metal in the pouring of the molten metal, the inner diameter D3 of the male joint 13 can be preferably 65 mm or more and more preferably 90 mm or more.

Further, from the viewpoint of handling properties, the inner diameter D3 of the male joint 13 can be preferably 700 mm or less, more preferably 550 mm or less, and even more preferably 350 mm or less.

The outside cover layer 32 of the female joint 12 may be discontinuous in the circumferential direction of the structure 1, according to one or more embodiments of the present disclosure. However, from the viewpoint of effectively preventing the leakage of the molten metal, the outside cover layer 32 can be continuous over the entire circumference in the circumferential direction of the structure 1.

Further, additionally or alternatively, the outside cover layer 32 of the female joint 12 may cover only a part of the outer face of the female joint 12 in the axial direction Z. However, from the viewpoint of effectively preventing the leakage of the molten metal, the outside cover layer 32 can cover the entire region of the outer face of the female joint 12 in the axial direction Z.

According to one or more embodiments of the present disclosure, it may be that the outside cover layer 32 is continuous over the entire circumference in the circumferential direction of the structure 1 and covers the entire region of the outer face of the female joint 12 in the axial direction Z. In other words, according to one or more embodiments of the present disclosure, the outside cover layer 32 can cover the entire region of the outer face of the female joint 12.

In the structure 1, the outer diameter D1 of the end part of the structure 1 other than the female joint 12 may be equal to or smaller than the inner diameter D2 of the female joint 12 as described above. This can make it easier to insert the end part of the structure 1 other than the female joint 12 into the female joint 12 of the other structure 1, and thus both the structures can be easily joined to each other.

From the viewpoint of making it much easier to insert the end part 13 of the structure 1 other than the female joint 12, i.e., the male joint 13 of the structure 1, into the female joint 12 of the other structure 1, a ratio D1/D2 of the outer diameter D1 to the inner diameter D2 can be preferably 1 or less, more preferably 0.999 9 or less, and even more preferably 0.999 5 or less.

Further, from the viewpoint of preventing the gap between the outer face of the male joint 13 and the inner face of the female joint 12 from becoming excessively large and further stabilizing the joined state therebetween when the male joint 13 of the structure 1 and the female joint 12 of the other structure 1 are joined to each other, the ratio D1/D2 can be preferably 0.9 or more, more preferably 0.95 or more, and even more preferably 0.99 or more.

From the viewpoint of achieving both of these, the ratio D2/D1 can be preferably 0.9 or more and less than 1, more preferably 0.95 or more and 0.999 9 or less, and even more preferably 0.99 or more and 0.999 5 or less.

In the structure 1, an outer diameter D4 of the female joint 12 can be the largest among the outer diameters of the structure 1. Thus, when the molten metal is poured in the state where the plurality of structures 1 are coupled to each other, the flow of the molten metal can be made smooth.

Further, in the structure 1, the inner diameter D2 of the female joint 12 can be the largest among the inner diameters of the structure 1. Thus, when the molten metal is poured in the state where the plurality of structures 1 are coupled to each other, the flow of the molten metal can be made smooth.

Next, the structures 1 of example second to ninth embodiments of the present disclosure are described. The second to ninth embodiments are described in the points different from the first embodiment, and the description of the first embodiment is applied as appropriate to the points that are not particularly described.

FIG. 6 shows the structure 1 of the second embodiment.

The structure 1 can have the female joint inside cover layer 33 covering the inner face of the female joint 12. The inner face of the female joint 12 can include the inner circumferential surface 12a of the female joint 12 and the upper surface 12e of the step part 15.

The female joint inside cover layer 33 can cover both the inner circumferential surface 12a and the upper surface 12e. In other words, the female joint inside cover layer 33 can cover the entire region of the inner face of the female joint 12. This example is shown in FIG. 6.

The structure 1 can have the female joint inside cover layer 33, and therefore can effectively prevent the leakage of the molten metal in the pouring of the molten metal. Hereinafter, this point is described in detail.

When the structures 1 are coupled to each other, the gap may be sometimes generated between the end face 11e of one structure 1 and the end face 12e arranged inside the other structure 1 as described above. Since the female joint inside cover layer 33 can be provided, the gap can be made smaller and can be made hard to generate.

Further, even when the gap is generated and the molten metal enters the gap, the female joint 12 can be protected. This can be because the inner face of the female joint 12, particularly the inner face of the corner part of the female joint, can be covered with the female joint inside cover layer 33. This example is shown in FIG. 6.

The molten metal entering the gap may pose a risk of entering between the outer circumferential surface of the male joint 13 of one structure 1 and the inner circumferential surface 12a of the female joint 12 of the other structure 1. However, the inner circumferential surface 12a of the female joint 12 can also be covered with the female joint inside cover layer 33, and therefore this entry can also be prevented. This can be because the female joint inside cover layer 33 can be arranged between the outer circumferential surface of the male joint 13 of one structure 1 and the inner circumferential surface 12a of the female joint 12 of the other structure 1.

Even when the molten metal enters between both the surfaces, the female joint 12 can be protected. This can be because the inner circumferential surface 12a of the female joint 12 can be covered with the female joint inside cover layer 33. This example is shown in FIG. 6.

The structure 1 may have not only the female joint inside cover layer 33 but the outside cover layer 32 of the female joint 12, according to one or more embodiments of the present disclosure. More specifically, both the inner face and the outer face of the female joint 12 can be covered. This can also contribute to more effectively preventing the leakage of the molten metal to the outside of the structure 1 in the pouring of the molten metal.

From the viewpoint of exhibiting the effect of protecting the female joint 12, the female joint inside cover layer 33 can be continuous over the entire circumference in the circumferential direction of the structure 1 and more preferably can cover the entire region of the inner face of the female joint 12.

The female joint inside cover layer 33 and the body inside cover layer 31 can be continuous according to one or more embodiments of the present disclosure. This can make it possible to protect the inner faces of the female joint 12 and the body part 11 without any gap.

The female joint inside cover layer 33 and the body inside cover layer 31 may be discontinuous according to one or more embodiments of the present disclosure. For example, the female joint inside cover layer 33 and the body inside cover layer 31 may be separate bodies.

According to one or more embodiments of the present disclosure, the entire region of the inner face of the main body 20 can be covered with the female joint inside cover layer 33 and the body inside cover layer 31. This can make it possible to protect the entire region of the inner face of the main body 20, and therefore the leakage of the molten metal in the pouring of the molten metal can be more effectively prevented.

FIG. 7 shows the structure 1 of the third embodiment.

The structure 1 can have an end face cover part 34 covering the outermost end face of the structure 1 in the female joint 12 (hereinafter also referred to as the “end face cover part of the female joint”).

The end face cover part 34 may cover only a part of the end face of the female joint 12 or may cover the entire region of the end face.

The end face cover part 34 of the female joint 12 can be provided, and therefore the leakage of the molten metal from the structure 1 in the pouring of the molten metal can be prevented. Hereinafter, this point is described in detail.

When the structures 1 are coupled to each other, the molten metal may sometimes enter the gap that may be generated between the end face 11e of one structure 1 and the end face 12e of the other structure 1 as described above. Thereafter, the molten metal may sometimes enter between the inner face of the female joint 12 of one structure 1 and the outer face of the male joint 13 of the other structure 1. Then, the molten metal may pose a risk of leaking to the outside of the structure 1 from the one end 1a side of one structure 1, i.e., the end face side of the female joint 12 of one structure 1. However, the leakage of the molten metal from the end face side of the female joint 12 of the structure 1 to the outside of the structure 1 can be prevented by covering the end face of the female joint 12 by the end face cover part 34.

From the viewpoint of exhibiting this effect, the end face cover part 34 can be continuous over the entire circumference in the circumferential direction of the structure 1, and more preferably can cover the entire region of the end face of the female joint 12.

In the structure 1 having the outside cover layer 32 of the female joint 12, the outside cover layer 32 and the end face cover part 34 of the female joint 12 may be discontinuous. However, from the viewpoint of more effectively preventing the leakage of the molten metal in the pouring of the molten metal, the outside cover layer 32 and the end face cover part 34 may be continuous, and preferably integrally molded.

FIG. 8 shows the structure 1 of the fourth embodiment.

The structure 1 can have a body outside cover layer 35 covering the outside of the body part 11.

Further, additionally or alternatively, the structure 1 can have the body inside cover layer 31.

In the structure 1, both the inner face and the outer face of the body part 11 may be covered. This example is shown in FIG. 8.

Since the structure 1 can have the body inside cover layer 31 and the body outside cover layer 35, the leakage of the molten metal in the pouring of the molten metal, particularly the leakage of the molten metal through the body part 11, can be effectively prevented. For example, even when the molten metal in the structure 1 has a high pressure, the leakage of the molten metal can be prevented.

From the viewpoint of exhibiting this effect, the body outside cover layer 35 can be continuous over the entire circumference in the circumferential direction of the structure 1.

In the structure 1 having the female joint inside cover layer 33, the female joint inside cover layer 33 and the body inside cover layer 31 can be continuous, and both can be integrally molded from the viewpoint of protecting the female joint 12 and the inner face of the body part 11 without any gap.

The outside cover layer 32 can extend to the inner face of the body part 11 through the end face of the female joint 12, according to one or more embodiments of the present disclosure. In other words, the outside cover layer 32 of the female joint 12, the end face cover part 34 of the female joint 12, the female joint inside cover layer 33, and the body inside cover layer 31 may be continuous.

The body outside cover layer 35 may also extend to the inner face of the body part 11 through the outer face and the end face of the female joint 12. In other words, the structure 1 of the fourth embodiment can have the body outside cover layer 35, the outside cover layer 32 of the female joint 12, the end face cover part 34 of the female joint 12, the female joint inside cover layer 33, and the body inside cover layer 31, and that these can be continuous.

The body inside cover layer 31 and the female joint inside cover layer 33 may be formed as separate bodies. In this case, it may be that the female joint inside cover layer 33 can extend to the inner face of the body part 11, and can partially overlap with the body inside cover layer 31. The female joint inside cover layer 33 can partially overlap with the body inside cover layer 31, and therefore the leakage of the molten metal from the interface between the body inside cover layer 31 and the female joint inside cover layer 33, which are formed as separate bodies, can be suppressed. This example is shown in FIG. 9.

When the female joint inside cover layer 33 partially overlaps with the body inside cover layer 31, either may be positioned on the inner side in the radial direction of the structure 1. However, according to one or more embodiments, the female joint inside cover layer 33 can be positioned on the inner side in the radial direction of the structure 1 relative to the body inside cover layer 31. By setting the positional relationship between the female joint inside cover layer 33 and the body inside cover layer 31 to such a positional relationship, the molten metal flowing in the structure 1 from the one end 1a side to the other end 1b side can be prevented from colliding with the end part on the one end 1a side in the body inside cover layer 31, which can make it possible to prevent the body inside cover layer 31 from peeling with the end part on the one end 1a side as the starting point in the pouring of the molten metal.

Under a case where the female joint inside cover layer 33 partially overlaps with the body inside cover layer 31, a thickness T1 of a portion where both overlap with each other can be larger than both the thickness of a portion having the largest thickness in the female joint inside cover layer 33 (hereinafter also referred to as a “maximum thickness of the female joint inside cover layer”) T2 and the thickness of a portion having the largest thickness in the body inside cover layer 31 (hereinafter also referred to as a “maximum thickness of the body inside cover layer”) T3. FIG. 9 shows examples of T1 to T3.

The body inside cover layer 31 and the female joint inside cover layer 33 may have a fixed thickness. Herein, the “fixed thickness” can include a case where unintended slight changes in thickness occur, such as changes in thickness that are inevitable during production.

One advantage of the thickness T1 being larger than the thickness T2 can be as follows. When the plurality of structures 1 are coupled to each other and the molten metal is poured, the flow of the molten metal may be disturbed in connection parts between the structures 1. However, the thickness T1 can be larger than the thickness T2, and therefore the flow of the molten metal can be prevented from being disturbed and the molten metal can be suppressed from colliding with the corner part of the female joint 12, and therefore the corner part of the female joint 12 can be protected.

One advantage of the thickness T1 being larger than the thickness T3 can be as follows. In general, when the molten metal is poured, the molten metal can be made to flow from the one end 1a side of the structure 1 where the female joint 12 is arranged toward the other end 1b side. The thickness T1 can be larger than the thickness T3, and therefore the molten metal flowing in the structure 1 can be prevented from colliding with the end part on the one end 1a side in the body inside cover layer 31. This can protect the body inside cover layer 31 in the pouring of the molten metal.

A ratio T1/T2 of the thickness T1 to the thickness T2 can be preferably more than 1, more preferably 1.5 or more, and even more preferably 2 or more, for instance, from the viewpoint of protecting the corner part of the female joint 12.

The ratio T1/T2 can be preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less, for instance, from the viewpoint of protecting the female joint inside cover layer 33 from friction when the structures 1 are connected to each other.

From the viewpoint of achieving both of these, for instance, the ratio T1/T2 can be preferably more than 1 and 15 or less, more preferably 1.5 or more and 10 or less, and even more preferably 2 or more and 5 or less.

A ratio T1/T3 of the thickness T1 to the thickness T3 can be preferably more than 1, more preferably 1.1 or more, and even more preferably 1.2 or more, for instance, from the viewpoint of protecting the body inside cover layer 31 in the pouring of the molten metal.

The ratio T1/T3 can be preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less, for instance, from the viewpoint of smoothing the flow of the molten metal in the connection parts between the structures 1 in the pouring of the molten metal.

From the viewpoint of achieving both of these, the ratio T1/T3 can be preferably more than 1 and 5 or less, more preferably 1.1 or more and 3 or less, and even more preferably 1.2 or more and 2 or less.

The maximum thickness T2 of the female joint inside cover layer 33 can be smaller than the maximum thickness T3 of the body inside cover layer 31. Thus, the end part on the other end 1b side of the other structure 1 can be easily inserted and joined to the female joint 12 of the structure 1.

From the viewpoint of making it easy to join the end part on the other end 1b side of the other structure 1 to the female joint 12 of the structure 1, for instance, a ratio T2/T3 of the thickness T2 to the thickness T3 can be preferably less than 1, more preferably 0.8 or less, and even more preferably 0.5 or less.

Further, from the viewpoint of protecting the main body 20 in the female joint 12, for instance, the ratio T2/T3 can be preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more.

From the viewpoint of achieving both of these, the ratio T2/T3 can be preferably 0.01 or more and less than 1, more preferably 0.05 or more and 0.8 or less, and even more preferably 0.1 or more and 0.5 or less.

According to one or more embodiments of the present disclosure, the thicknesses of the body inside cover layer 31 and the female joint inside cover layer 33 do not have to be fixed. FIG. 10 shows an example of the structure 1 in which the thickness of the body inside cover layer 31 is not fixed.

When the thickness of the body inside cover layer 31 is not fixed, the body inside cover layer 31 can have a portion having a thickness larger than that of a portion 31a arranged in the end part on the one end 1a side in the axial direction Z of the body part 11 in the body inside cover layer 31. Thus, when the molten metal flowing inside the cylindrical body 10 obtained by coupling the structures 1 passes through the inside of the body part 11 of the structure 1 on the upstream side in a direction Z1 in which the molten metal flows to enter the body part 11 of the structure 1 on the downstream side in the direction Z1, the flow of the molten metal may find it hard to directly collide with the surface of the body inside cover layer 31 covering the inner face of the end part on the one end 1a side of the body part 11 in the structure 1 on the downstream side. This can prevent the application of impact to the end part on the one end 1a side of the body part 11 of the structure 1 on the downstream side, and thus the body inside cover layer 31 can be protected. From the viewpoint of exhibiting this effect, the portion 31a can have the smallest thickness in the body inside cover layer 31.

The thickness of the body inside cover layer 31 can gradually increase from the one end 1a side toward the other end 1b side in the axial direction Z. This example is shown in FIG. 10.

When the body inside cover layer 31 and the female joint inside cover layer 33 are formed as separate bodies, the position of an edge on the proximal end side in a consecutively connecting direction Y of the female joint 12 of the female joint inside cover layer 33 may or may not coincide with the position of an edge on a proximal end side in the consecutively connecting direction Y of the female joint 12 of the outside cover layer 32. From the viewpoint that the structure 1 having the female joint inside cover layer 33 and the outside cover layer 32 can be simply produced, the position of an edge 33b on the proximal end side in the female joint inside cover layer 33 and the position of an edge 32b on the proximal end side in the outside cover layer 32 can coincide with each other.

Herein, the description “the position of the edge 33b of the female joint inside cover layer 33 and the position of the edge 32b of the outside cover layer 32 coincide with each other” can include not only a case where both the positions in the consecutively connecting direction Y of the female joint 12 completely coincide with each other but a case where both the positions are approximated to such an extent that the positions are assumed to substantially coincide with each other. Specifically, when a ratio of a distance L5 in the consecutively connecting direction Y between the edge 33b of the female joint inside cover layer 33 and the edge 32b of the outside cover layer 32 to a length L4 in the consecutively connecting direction Y of the outer face of the female joint 12 is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less, as examples, the position of the edge 33b of the female joint inside cover layer 33 and the position of the edge 32b of the outside cover layer 32 can be assumed to coincide with each other. Examples of the length L4 and the distance L5 are shown in FIG. 11.

In the structure 1, according to one or more embodiments of the present disclosure, the thickness of the female joint inside cover layer 33 can be the smallest among the cover layers covering the surfaces of the main body 20. In other words, the thickness of the female joint inside cover layer 33 can be smaller than the thicknesses of the cover layers other than the female joint inside cover layer 33. Thus, the end part of the structure 1 other than the female joint 12 can be easily inserted into the female joint 12, and both can be easily joined to each other. Even in a case where the cover layers are peeled when the male joint 13 is joined to the female joint 12, the peeling amount can be reduced and influence on the product quality can be reduced.

FIG. 12 shows a structure 1B of the fifth embodiment.

The structure 1B can be provided with the cylindrical main body 20.

The main body 20 can have the male joint 13 in one end part of the body part 11.

The male joint 13 can be internally joined to the female joint 12. The male joint 13 can have an outer diameter equal to or smaller than the inner diameter of the female joint 12.

In the structure 1B, the female joint 12 having the inner diameter equal to or larger than the outer diameter of the body part 11 can be coupled to the other end part of the body part 11.

The female joint 12 can have the inner diameter and the outer diameter larger than those of the body part 11. The end part on the female joint 12 side in the body part 11 can be formed with the step part 15 projecting outward in the radial direction of the body part 11, and the female joint 12 can be consecutively connected to the body part 11 via the step part 15.

As the structure 1B, according to one or more embodiments of the present disclosure, more than one structure of the same or a similar type can be coupled to each other.

In the structure 1B of the example shown in FIG. 12, both the ends in the axial direction Z in the main body 20 can be regarded as being in an open state.

The inner diameter of the female joint 12 can be equal to or larger than the outer diameter on the male joint 13 side of the body part 11.

The structure 1B can be configured such that the structures 1B can be coupled to each other by inserting and joining the male joint 13 of the structure 1B to the female joint 12 of the other structure 1B. By coupling a desired number of the structures 1B, a long cylindrical body 10 having a desired length can be formed. This example is shown in FIG. 14.

The structure 1B can have the body inside cover layer 31 and an outside cover layer 36 covering the outer face of the male joint 13 (hereinafter also referred to as the “outside cover layer of the male joint”).

The outside cover layer 36 of the male joint 13 can contain refractory inorganic particles, for instance, selected from the group consisting of metal oxides and metal silicates, a binder, and clay minerals. Each component contained in the outside cover layer 36 is described later.

The body inside cover layer 31 can be continuous over the entire circumference in the circumferential direction of the structure 1B. This example is shown in FIG. 13 (b).

Additionally or alternatively, the body inside cover layer 31 can be continuous over the entire region of the body part 11 in the axial direction Z. More specifically, the body inside cover layer 31 can cover the entire region of the inner face of the body part 11 also in the structure 1B. This example is shown in FIG. 13 (a).

The structure 1B can have the body inside cover layer 31, and therefore gas may be hard to get mixed into the molten metal flowing in the structure 1B. From the viewpoint of exhibiting this effect, the body inside cover layer 31 can be continuous over the entire circumference in the circumferential direction of the structure 1B and more preferably can cover the entire region of the inner face of the body part 11.

The outside cover layer 36 can cover the entire region of the outer face of the male joint 13.

The structure 1B of the fifth embodiment can also be used to produce a casting in the same manner as the structure 1 of the first embodiment.

The structure 1B can have the outside cover layer 36 of the male joint 13, and therefore can prevent the leakage from the structure 1B in the pouring of the molten metal. Hereinafter, this point is described in detail.

When the structures 1B are coupled to each other, a gap may sometimes be generated between end face 11e of the male joint 13 of one structure 1B and the end face 12e arranged inside the female joint 12 of the other structure 1B. The molten metal entering the gap may pose a risk of entering between the outer circumferential surface 11b of the male joint 13 of one structure 1B and the inner circumferential surface 12a of the female joint 12 of the other structure 1B. However, the structure 1B can prevent the molten metal from entering between the outer circumferential surface 11b and the inner circumferential surface 12a. This can be because the outer circumferential surface 11b of the male joint 13 can also be covered with the outside cover layer 36. Further, this can be because the outside cover layer 36 of the male joint 13 can be arranged between the outer circumferential surface 11b of the male joint 13 of one structure 1B and the inner circumferential surface 12a of the female joint 12 of the other structure 1B.

Further, according to one or more embodiments, the structure 1B having the outside cover layer 36 of the male joint 13 and the body inside cover layer 31, and the outer face and the inner face of the male joint 13 can be covered. This can make it possible to effectively prevent the leakage of the molten metal through the male joint 13 in the pouring of the molten metal.

The outside cover layer 36 of the male joint 13 may be discontinuous in the circumferential direction of the structure 1B, according to one or more embodiments, but alternatively can be continuous over the entire circumference in the circumferential direction of the structure 1B, for instance, from the viewpoint of effectively preventing the leakage of the molten metal.

In the fifth embodiment, the body inside cover layer 31 can cover the entire region of the inner face of the body part 11 as described above. This can make it possible to protect the entire region of the inner face of the main body 20, and therefore the leakage of the molten metal in the pouring of the molten metal can be prevented.

Also in the structure 1B of the fifth embodiment, the effect that the leakage of the molten metal in the pouring of the molten metal can be prevented may be exhibited when the inner diameter D3 of the body part 11 in the structure 1 is large as with the structure 1 of the first embodiment.

An example of a numerical range of the inner diameter D3 of the male joint 13 according to the fifth embodiment can be the same as that of the first embodiment.

FIG. 16 shows the structure 1B of the sixth embodiment.

The structure 1B can have the outside cover layer 36 of the male joint 13 and an end face cover part 37 covering the end face 11e of the male joint 13 (hereinafter also referred to as the “end face cover part of the male joint”). The end face cover part 37 may cover only a part of the end face of the male joint 13 or may cover the entire region of the end face.

The end face cover part 37 of the male joint 13 can be provided, and therefore the leakage of the molten metal from in the pouring of the molten metal can be effectively prevented. Hereinafter, this point is described in detail.

When the structures 1B are coupled to each other, a gap may sometimes be generated between the end face 11e of the male joint 13 of one structure 1B and the end face 12e arranged inside the female joint 12 of the other structure 1B. The structure 1B can have the end face cover part 37 of the male joint 13, and thus can reduce the gap to make it hard to form the gap. This example is shown in FIG. 16.

When the structure 1B has the outside cover layer 36 of the male joint 13, the outside cover layer 36 and the end face cover part 37 of the male joint 13 may be discontinuous. However, from the viewpoint of more effectively preventing the leakage of the molten metal in the pouring of the molten metal, for instance, the outside cover layer 36 and the end face cover part 37 can be continuous, and preferably integrally molded.

When the structure 1B has the body inside cover layer 31, the end face cover part 37 of the male joint 13 can be continuous with the body inside cover layer 31, and these can be preferably integrally molded.

The outside cover layer 36 of the male joint 13 can extend to the inner face of the body part 11 through the end face of the male joint 13.

The outer diameter D1 of the male joint 13 can be equal to or smaller than the inner diameter D2 of the end part on the other end side opposite to one end in the axial direction Z in the body part 11, i.e., the female joint 12. Thus, the male joint 13 of the structure 1B can be easily inserted into the female joint 12 of the other structure 1B, and both can be easily joined to each other.

An example of a numerical range of the ratio D1/D2 of the outer diameter D1 to the inner diameter D2 can be the same as the numerical range of the ratio D1/D2 in the first embodiment.

The body inside cover layer 31 can be arranged on the innermost side in the radial direction of each of the structures 1 and 1B in the portion where the body inside cover layer 31 is arranged. Thus, the body inside cover layer 31 in each of the structures 1 and 1B can come into contact with the molten metal passing through the inside of each of the structures 1 and 1B, and therefore the main body 20 in each of the structures 1 and 1B can be easily protected.

In the example of the structure 1 shown in FIG. 1, the radial direction of the structure 1 in the portion where the body inside cover layer 31 is arranged can be regarded as the radial direction in the transverse cross section orthogonal to the axial direction Z of the structure 1. In the example of the structure 1 shown in FIG. 17 (d), the radial direction of the structure 1 in the portion where the body inside cover layer 31 is arranged can be regarded as the radial direction in the transverse cross section orthogonal to the axial direction Zx of the first part 18 in the case of the body inside cover layer 31 arranged in the first part 18 and can be the radial direction in the transverse cross section orthogonal to an axial direction Zy of the second part 19, i.e., the consecutively connecting direction Y of the female joint 12, in the case of the body inside cover layer 31 arranged in the female joint 12.

The outside cover layer 32 of the female joint 12 can be arranged on the outermost side in the radial direction in the transverse cross section orthogonal to the axial direction Z of the structure 1, according to one or more embodiments of the present disclosure. Thus, both the simplicity of the production and the protection of the main body 20 can be achieved.

The main body 20 may have a laminated structure in which two or more layers are laminated. However, from the viewpoint of simple production, for instance, the main body 20 can have or be in the form of a single layer structure.

The main body 20 can be integrally molded in the circumferential direction. Thus, the main body 20 can become continuous over the entire circumference in the circumferential direction, and therefore the formation of gaps or holes in the main body 20 can be prevented, and the leakage of the molten metal in the pouring of the molten metal can be effectively prevented.

The structures 1 and 1B can have portions not covered with the cover layers 32, 35 and 36 in parts of the outer face of the main body 20. In the pouring of the molten metal, gas may be generated when the organic fibers, the binder, and the like contained in the main body 20 are thermally decomposed due to the flow of the molten metal into the structure 1. Since parts of the outer face of the main body 20 may not be covered with the cover layers 32, 35, and 36, the gas can be discharged from the parts to the casting sand side, i.e., the outside of the structures 1 and 1B.

The outer face of any of the body part 11, the male joint 13, and the female joint 12 in the main body 20 may have portions not covered with the cover layers 32, 35 and 36. From the viewpoint of exhibiting the effect of discharging the gas to the outside of the structures 1 and 1B, a portion not covered with the body outside cover layer 35 can be present in the outer face of the body part 11 in the main body 20.

An uncovered area ratio that is a ratio of the area of the portion not covered with the body outside cover layer 35 to an entire area SI of the outer face of the body part 11 can be preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more, for instance, from the viewpoint of preferentially discharging the gas to the outside of the structures 1 and 1B.

The uncovered area ratio can be preferably 100% or less, more preferably 95% or less, and even more preferably 90% or less, for instance, from the viewpoint of preventing the leakage of the molten metal to the outside of the structure 1 in the pouring of the molten metal.

From the viewpoint of achieving both of these, for instance, the uncovered area ratio can be preferably 30% or more and 100% or less, more preferably 50% or more and 95% or less, and even more preferably 70% or more and 90% or less.

Next, examples of constituent materials of the structures 1 and 1B are described.

The main body 20, according to one or more embodiments, can contain, comprise, or consist of organic fibers, inorganic fibers, inorganic particles (hereinafter also referred to as first inorganic particles), and a binder (hereinafter also referred to as a first binder).

Such a main body 20 may be produced by the following method, as but one example. First, a slurry composition containing organic fibers, inorganic fibers, the first inorganic particles, the first binder, and a dispersion medium (hereinafter referred to as a raw material slurry) can be prepared. Subsequently, an intermediate molded body of the main body 20, e.g., a main body in a water-containing state, can be made into a sheet using a mold for sheet-making and dehydration molding. Next, by heating and drying the intermediate molded body using the mold, the main body 20 can be formed.

The organic fibers can be entangled with the inorganic fibers, the inorganic particles before being used for casting in the main body 20 and can exhibit the effect of maintaining the shapes of the structures 1 and 1B. In casting, some or all of the organic fibers burn by the heat of the molten metal.

For the organic fibers, one type or two or more types selected from pulp fibers, synthetic fibers, regenerated fibers (for example, rayon fibers), and the like can be used.

Among the above, pulp fibers can be preferably contained. A reason therefor can be that the pulp fibers can be molded into various shapes by sheet-making, the dehydrated and dried molded product has excellent strength characteristics, and the pulp fibers may be easily available, stable, and economical.

For the pulp fibers, one type or two or more types selected from wood pulp, cotton pulp, linter pulp, bamboo, straw, and other non-wood pulp can be used. Further, one type or two or more types selected from virgin pulp or waste paper pulp (recycled product) can be used.

In the respects of easy availability, environmental protection, and reduction in production cost, waste paper pulp, such as waste newspaper, may be preferably contained.

The inorganic fibers can improve the strength of the structures 1 and 1B, for instance, before being used for casting in the main body 20. The inorganic fibers can maintain the shape without burning even by the heat of the molten metal in casting. In particular, when organic binders described later are used, the inorganic fibers can suppress the heat shrinkage caused by the burning of the organic fibers by the heat of the molten metal and the thermal decomposition of the organic binder.

For the inorganic fibers, one type or two or more types selected from carbon fibers, artificial mineral fibers, such as rock wool, ceramic fibers, glass fibers, and natural mineral fibers can be used.

Among the above, carbon fibers may be preferably contained, which can have high strength even at high temperatures where metal melts, for instance, from the viewpoint of suppressing the above-described heat shrinkage.

In the respect of reducing the production cost, one type or two or more types selected from rock wool and glass fibers may be contained.

As the first inorganic particles, one type or two or more types selected from refractory aggregate particles, such as mullite, graphite, mica, silica, hollow ceramics, and fly ash, can be used.

From the viewpoint of improving the air permeability of the main body 20, for instance, the average particle size of the first inorganic particles can be preferably 10 μm or more and more preferably 15 μm or more.

The average particle size of the first inorganic particles can be preferably 100 μm or less, for instance, from the viewpoint of improving the moldability of the main body 20.

When the average particle size of the first inorganic particles is equal to or larger than the lower limits above, the permeability of the main body 20 can be improved, and the gas pressure in the mold in casting can moderately decrease. Further, the improvement of the permeability of the main body 20 can increase gaps between the materials of the main body 20, can improve the permeability of a coating composition described later into the main body 20, and/or can makes it hard for the cover layers to peel from the main body 20.

When the average particle size of the first inorganic particles is equal to or larger than the upper limits above, the inorganic particles may be hard to fall off from the surface of the main body 20, and the moldability can be improved.

From the viewpoint of raw material dispersibility, for instance, the apparent specific gravity of the first inorganic particles can be preferably 0.5 or more and more preferably 2.8 or more.

From the viewpoint of weight reduction, for instance, the apparent specific gravity of the first inorganic particles can be preferably 3 or less, more preferably 2.8 or less, and even more preferably 2.5 or less.

The apparent specific gravity can be regarded as the specific gravity of hollow particles supposing that the volume of the hollow portion inside the hollow particle can be a part of the volume of the hollow particle, and can coincide with the true specific gravity in the case of solid particles having no internal hollow portion.

The apparent specific gravity of the first inorganic particles can be in the range above, and therefore the raw material dispersibility in a sheet-making step when water is used as a dispersion medium can be improved. Further, the mass of the main body 20 obtained by molding can be reduced, and therefore the handleability can be improved.

The composition of the main body 20 can be determined considering the bulk specific gravity together with the apparent specific gravity of the first inorganic particles. The bulk specific gravity may be obtained by measuring the amount of particles that a container with a fixed volume can hold when the particles are placed in the container in a fixed state and determining the mass per unit volume.

The first inorganic particles may be hollow. The use of the hollow particles can reduce the apparent specific gravity of the first inorganic particles.

In one or more embodiments of the present disclosure, one type or two or more types selected from organic binders and inorganic binders can be used as the first binder.

The organic binder can be contained, for instance, from the viewpoint of excellent removability after casting.

As the organic binder, one type or two or more types selected from thermosetting resins, such as a phenol resin, an epoxy resin, and a furan resin, can be used.

Among the above, the phenol resin can be contained, for instance, because the phenol resin may hardly generate flammable gas, can have a combustion suppressing effect, and can have a high residual coal ratio after thermal decomposition (carbonization).

As the phenol resin, one type or two or more types selected from phenol resins, such as a novolak phenol resin and a resol type, and modified phenol resins modified with urea, melamine, epoxy, and the like, for example, can be used.

Among the above, the resol-type phenol resin can be contained, for instance, because the odor in molding of the main body 20 and casting defects when the main body 20 is used as a mold can be reduced without requiring curing agents, such as acids and amines.

When the novolac phenol resin is used, the curing agent can be used in combination. The curing agent may be easily soluble in water, and therefore can be applied to the surface of the main body 20 after dehydration. For the curing agent, hexamethylenetetramine and the like can be used.

As the inorganic binder, one type or two or more types selected from a phosphoric acid binder, water glass, such as silicate, gypsum, sulfate, a silica binder, and a silicon binder can be used.

As the dispersion medium used for the raw material slurry, one type or two or more types selected from solvents, such as water, ethanol, methanol, dichloromethane, acetone, and xylene, can be used.

Among the above, water can be contained, for instance, from the viewpoint of ease of handling.

According to one or more embodiments, the main body 20 may contain, comprise, or consist of paper strengthening materials in addition to the organic fibers, the inorganic fibers, the first inorganic particles, and the first binder. The paper strengthening materials can act on maintaining the shape of the intermediate molded body.

As the paper strengthening materials, one type or two or more types selected from latex, an acrylic emulsion, polyvinyl alcohol, carboxymethyl cellulose, a polyacrylamide resin, a polyamide epichlorohydrin resin, and the like can be used.

The body inside cover layer 31, the outside cover layer 32 of the female joint 12, the female joint inside cover layer 33, the end face cover part 34 of the female joint 12, the body outside cover layer 35, the outside cover layer 36 of the male joint 13, and the end face cover part 37 of the male joint 13 (hereinafter, these are sometimes collectively referred to as “cover layers”) can be formed, as an example, by applying, to the surface of the main body 20, a coating composition containing refractory inorganic particles, for instance, having an average particle size of 1 μm or more and 100 μm or less selected from the group consisting of metal oxides and metal silicates (hereinafter also referred to as second inorganic particles), a binder (hereinafter also referred to as a second binder), and clay minerals.

With respect to the refractory inorganic particles, the “refractory” can mean that the melting point is 1 500° C. or more, preferably 1 600° C. or more, and more preferably 1 700° C. or more, as examples.

For the second inorganic particles, one type or two or more types selected from the group consisting of metal oxides and metal silicates can be used.

Specifically, one type or two or more types selected from mullite, zircon, zirconia, alumina, olivine, spinel, magnesia, chromite, and the like can be used.

From the viewpoint of improving gas defects of castings, zircon can be contained.

According to one or more embodiments, steel having a carbon content smaller than that of cast iron can contain aggregate particles other than carbonaceous substances and more preferably can contain zircon having a high melting point and low wettability with molten metal.

From the viewpoint of the sealing properties of the surface of the main body 20 and the adhesion between the main body 20 and the cover layers, for instance, the average particle size of the second inorganic particles can be preferably 1 μm or more and more preferably 3 μm or more.

The average particle size of the second inorganic particles can be preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 40 μm or less.

In the structures 1 and 1B, the ratio between the average particle size of the first inorganic particles contained in the main body 20 and the average particle size of the second inorganic particles contained in the cover layers can be preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 0.8 or more in terms of [Average particle size of first inorganic particles]/[Average particle size of second inorganic particles], for instance, from the viewpoint of the sealing properties of the surface of the main body 20.

The ratio between the average particle size of the first inorganic particles contained in the main body 20 and the average particle size of the second inorganic particles contained in the cover layers can be preferably 35 or less, more preferably 30 or less, even more preferably 20 or less, and yet even more preferably 6 or less in terms of [Average particle size of first inorganic particles]/[Average particle size of second inorganic particles], for instance, from the viewpoint of the sealing properties of the surface of the main body 20.

In the structures 1 and 1B, the proportion of the second inorganic particles in the cover layer can be preferably 50% by mass or more and less than 100% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, and yet even more preferably 90% by mass or more.

The cover layers may contain clay minerals, for instance, from the viewpoint of improving the hot strength and imparting viscosity in application. By compounding clay minerals in a dispersion liquid (coating composition) for obtaining the cover layers, appropriate viscosity can be imparted to the dispersion liquid, and the prevention of sedimentation of the raw materials in the dispersion liquid and the raw material dispersibility can be improved.

As the clay minerals, one type or two or more types selected from layered silicate minerals, double chain structure minerals, and the like can be used. These substances may be natural or synthetic.

As the layered silicate minerals, one type or two or more types selected from clay minerals belonging to the smectite group, the genus kaolin, and the genus illite, e.g., bentonite, smectite, hectorite, activated clay, kibushi clay, zeolite, and the like, can be used.

As the double chain structure minerals, one type or two or more types selected from attapulgite, sepiolite, palygorskite, and the like can be used.

From the viewpoint of improving the hot strength and ensuring viscosity in application, for instance, one type or two or more types selected from attapulgite, sepiolite, bentonite, and smectite can be used, and one type or two or more types selected from attapulgite and sepiolite may be more preferably used.

The clay minerals can be distinguished in that the clay minerals have a layered structure or a double chain structure from the refractory inorganic particles mainly containing a hexagonal close-packed structure and generally may not have the layered structure or the double chain structure, for example.

The clay minerals can be contained in a proportion of preferably 0.5 parts by mass or more and more preferably 1 part by mass or more based on 100 parts by mass of the refractory inorganic particles.

The clay minerals can be contained in a proportion of preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 2 parts by mass or less based on 100 parts by mass of the refractory inorganic particles.

When the proportion of the clay minerals is equal to or larger than the lower limits above in the proportions above, appropriate viscosity can be imparted to the dispersion liquid, and sedimentation and floating of the raw materials in the dispersion liquid can be prevented.

The cover layers can further contain the second binder, for instance, from the viewpoint of improving the hot strength. The use of the second binder in the formation of the cover layers may be preferable, for instance, from the viewpoint of improving the normal temperature strength and the heat resistance of the structure for producing a casting.

As the second binder, one type or two or more types selected from the organic binders and the inorganic binders are usable, and the inorganic binders can be contained.

As the organic binder, one type or two or more types selected from a phenol resin, an epoxy resin, a furan resin, a water-soluble alkyd resin, a water-soluble butyral resin, polyvinyl alcohol, a water-soluble acrylic resin, water-soluble polysaccharide, a vinyl acetate resin or a copolymer thereof, and the like can be used, for example.

As the inorganic binder, one type or two or more types selected from various sols, such as sulfate, silicate, phosphate, lithium silicate, zirconia sol, colloidal silica, and alumina sol, and the like can be used, and one type or two or more types selected from the group consisting of colloidal silica and aluminum phosphate can be used, and colloidal silica may be preferably contained according to one or more embodiments of the present disclosure.

The second binder can be contained in a proportion of preferably 1 part by mass or more and more preferably 3 parts by mass or more in terms of the effective component based on 100 parts by mass of the second inorganic particles.

The second binder can be contained in a proportion of preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 7 parts by mass or less in terms of the effective component based on 100 parts by mass of the second inorganic particles.

One aspect of a method for producing a structure for producing a casting according to one or more embodiments of the present disclosure is described using a method for producing the structure 1 shown in FIG. 18 as an example.

The production method of this aspect can include a body part applying step of forming the body inside cover layer 31 and a female joint applying step of forming the female joint outside cover layer 32.

In the female joint applying step according to this aspect, the female joint inside cover layer 33 and the female joint end face cover part 34 may also be formed in addition to the female joint outside cover layer 32.

In the body part applying step, the body inside cover layer 31 can be formed by applying a coating composition to the inner face of the body part 11 of the main body 20. Specifically, the forming can involve pouring a coating composition 70 into the body part 11 and filling the coating composition 70 into the body part 11 (see, e.g., FIGS. 18 (a) and 18 (b)).

In detail, a lid 60 can be arranged at an opening end of the male joint 13. Then, the coating composition 70 can be filled into the body part 11. When the upper surface of the coating composition 70 reaches the desired height, the filling with the coating composition 70 may be regarded as finished. Then, after a certain period of time has elapsed, the lid 60 can be opened. Then, the coating composition 70 can be discharged leaving the coating composition 70 remaining on the inner face of the body part 11.

Then, optionally, the body part 11 on which the coating composition 70 remains can be left to stand in a state where the axial direction Z of the body part 11 is set to be substantially parallel to the vertical direction Z1, and the coating composition 70 remaining on the inner face of the body part 11 can be dried and solidified to form the body inside cover layer 31 on the inner face of the body part 11 (see, e.g., FIG. 18 (c)).

The female joint applying step can be performed after the body part applying step. In the female joint applying step, the coating composition can be applied to the inner face, the outer face, and the end face of the female joint 12 in the main body 20 over the entire circumference of the female joint 12.

In detail, the female joint 12 in the main body 20 can be dipped in a coating composition 71. Then, the coating composition 71 can be spread to the inner face, the outer face, and the end face of the female joint 12 (see, e.g., FIG. 18 (d)). Thereafter, after a certain period of time has elapsed, the female joint 12 can be taken out from the coating composition 71. Then, the coating film, i.e., the coating composition 71 remaining on the inner face, the outer face, and the end face of the female joint 12, can be dried and solidified to form the female joint inside cover layer 33, the female joint outside cover layer 32, and the female joint end face cover part 34, respectively.

Thus, the structure 1 can be produced which can have the body inside cover layer 31, the female joint inside cover layer 33, the female joint outside cover layer 32, and the female joint end face cover part 34.

According to the production method of this aspect, the structure 1 can be efficiently produced.

In the body part applying step, the coating composition 70 to be filled into the body part 11 may reach the upper surface 12e of the step part 15 (see, e.g., FIG. 18 (b)) or may not reach the upper surface 12e (see, e.g., FIG. 19 (a)). The coating composition 70 to be filled into the body part 11 may reach up to the female joint 12 (see, e.g., FIGS. 19 (b) and 19 (c)). When the coating composition 70 reaches the female joint 12, the coating composition 70 may reach the opening end of the female joint 12 (see, e.g., FIG. 19 (b)) or may not reach the opening end of the female joint 12 (see, e.g., FIG. 19 (c)).

In the body part applying step, the coating composition 70 may be applied to the inner face of the body part 11 by applying the coating composition 70 to the inner face of the body part 11 with a brush or the like, for example, in place of filling the coating composition 70 into the body part 11.

From the viewpoint of making it possible to easily form the body inside cover layer 31 to more efficiently produce the structure 1, for instance, the coating composition 70 can be applied by filling the coating composition 70 into the body part 11.

In the female joint applying step, the female joint 12 may be dipped in the coating composition 71 to a lower surface 15a of the step part 15 in the main body 20 (see, e.g., FIG. 18 (d)), only a portion on the one end 1a side relative to the lower surface 15a of the step part 15 in the female joint 12 may be dipped in the coating composition 71 (see, e.g., FIG. 19 (d)), or the female joint 12 may be dipped in the coating composition 71 to a position on the other end 1b side relative to the lower surface 15a of the step part 15 in the main body 20 (see, e.g., FIG. 19 (e)).

In the female joint applying step of this aspect, the female joint inside cover layer 33, the female joint outside cover layer 32, and the female joint end face cover part 34 can be formed. However, in the female joint applying step, only the female joint outside cover layer 32 may be formed. The coating composition 71 may be applied to the outer face of the female joint 12 by applying the coating composition 71 to the outer face of the female joint 12 with a brush or the like, for example.

From the viewpoint of making it possible to easily form the female joint inside cover layer 33, the female joint outside cover layer 32, and the female joint end face cover part 34 to more efficiently produce the structure 1, for instance, the coating composition 71 can be applied by dipping the female joint 12 in the main body 20 in the coating composition 71 (see, e.g., FIG. 18 (d)).

The order of performing the female joint applying step and the body part applying step may not be particularly limited. For example, the body part applying step may be performed after the female joint applying step, or the female joint applying step and the body part applying step may be simultaneously performed.

The coating composition 70 in the body part applying step and the coating composition 71 in the female joint applying step may be the same or different from each other.

The main body 20 can be produced by the following method, for example.

<Method for Producing Main Body 20>

The main body 20 can be produced by a molding method having a sheet-making step.

Specifically, first, a raw material slurry can be prepared, which can contain the organic fibers, the inorganic fibers, the first inorganic particles, and the first binder in a predetermined proportion. The raw material slurry can be prepared by dispersing the organic fibers, the inorganic fibers, the first inorganic particles, and the first binder in a predetermined dispersion medium. The first binder may be compounded in the main body 20 by impregnation instead of being compounded in the raw material slurry.

As the dispersion medium, one type or two or more types selected from solvents, such as ethanol, methanol, dichloromethane, acetone, and xylene, can be used, in addition to water. Among the above, water can be contained from the viewpoint of ease of handling, for example.

As the content ratio of the organic fibers, the inorganic fibers, the first inorganic particles, and the first binder in the raw material slurry, the ratio of each component can be appropriately adjusted to achieve the composition of the target main body 20.

The raw material slurry can be added with additives, such as paper strengthening agents, flocculants, and antiseptics, as desired.

Next, the intermediate molded body of the main body 20 can be made into a sheet using the raw material slurry.

In the sheet-making step of the intermediate molded body, a sheet-making and dehydration molding mold can be used inside which a cavity having a shape corresponding to the outer shape of the intermediate molded body is formed by butting two split molds forming one pair to each other, for example. Then, a predetermined amount of the raw material slurry can be poured under pressure from an upper opening part into the cavity of the mold. This can pressurize the inside of the cavity to a predetermined pressure. Each split mold can be provided with a plurality of communication holes bringing the outside of each split mold and the cavity into communication with each other, and the inner face of each split mold can be covered with a net having meshes of a predetermined size. For the pouring under pressure of the raw material slurry, a pressure pump may be used, for example. The pressure of the pouring under pressure of the raw material slurry can be preferably 0.01 MPa or more and 5 MPa or less, more preferably 0.01 MPa or more and 3 MPa or less, and even more preferably 0.1 MPa or more and 0.5 MPa or less, according to one or more embodiments of the present disclosure.

As described above, the inside of the cavity can be pressurized, and therefore the dispersion medium in the raw material slurry can be discharged to the outside of the mold from the communication holes. The solid content in the raw material slurry may be deposited on the net covering the cavity, and a fiber laminate can be uniformly formed on the net. The fiber laminate thus obtained can be a laminate in which the organic fibers and the inorganic fibers are complicatedly entangled and the binder is present between the fibers. Therefore, high shape retention properties can be obtained even when the shape is complicated or even after drying and molding. Further, the inside of the cavity can be pressurized, and therefore, the raw material slurry can flow inside the cavity and the raw material slurry can be stirred even when a hollow intermediate molded body is molded. Therefore, the slurry concentration in the cavity can be made uniform, and the fiber laminate can be uniformly deposited on the net.

After the fiber laminate is formed, the pouring under pressure of the raw material slurry can be stopped, and air can be press-injected into the cavity to pressurize and dehydrate the fiber laminate. Thereafter, the press-injection of the air can be stopped, the inside of the cavity can be sucked through the communication holes, and an elastic, expandable, and hollow core (elastic core) can be inserted into the cavity. The core may be formed of urethane, fluororubber, silicone rubber, elastomer, or the like having excellent tensile strength, impact resilience, elasticity, and the like.

Next, a pressurized fluid can be supplied into the elastic core inserted into the cavity to expand the elastic core, and the expanded elastic core can press the fiber laminate against the inner face of the cavity. Thus, the fiber laminate can be pressed against the inner face of the cavity, and the inner face shape of the cavity can be transferred to the outer face of the fiber laminate and the dehydration of the fiber laminate proceeds.

For the pressurized fluid used to expand the elastic core, compressed air (heated air), oil (heated oil), or the other various types of liquids can be used, for example. The supply pressure of the pressurized fluid can be preferably 0.01 MPa or more and 5 MPa or less considering the production efficiency of the molded body, and is more preferably 0.1 MPa or more and 3 MPa or less and even more preferably 0.1 MPa or more and 0.5 MPa or less from the viewpoint of efficient production. When the supply pressure is 0.01 MPa or more, the drying efficiency of the fiber laminate may be regarded as good, and the surface properties and the transferability may also be regarded as sufficient. When the supply pressure is 5 MPa or less, a good effect can be obtained and the device can be downsized.

As described above, the fiber laminate can be pressed against the inner face of the cavity from the inside thereof, and therefore, the inner face shape can be accurately transferred to the outer face of the fiber laminate even when the inner face shape of the cavity is complicated. Further, even when a molded product to be produced has a complicated shape, there may be no need for a sticking step of each portion, and therefore the finally obtained part can be free from joints or thick portions caused by sticking. More specifically, the main body 20 to be finally obtained can be a product integrally molded in the circumferential direction of the main body 20.

When the inner face shape of the cavity is sufficiently transferred to the outer face of the fiber laminate and the fiber laminate can be dehydrated to have a predetermined moisture content, the pressurized fluid in the elastic core can be removed and the elastic core can be automatically shrunk to its original size. Then, the shrunk elastic core can be taken out from the inside of the cavity. Further, the mold can be opened and the fiber laminate in a wet state having a predetermined moisture content can be taken out. According to one or more embodiments, the fiber laminate can also be dehydrated and molded only by the pressurization and dehydration by the press-injection of the air into the cavity without the above-described pressing and dehydration of the fiber laminate using the elastic core.

The dehydrated and molded fiber laminate can then be transferred to a heating and drying step.

In the heating and drying step, a mold for drying and molding can be used in which a cavity having a shape corresponding to the outer shape of the intermediate molded body can be formed. Then, the mold can be heated to a predetermined temperature, and the dehydrated and molded fiber laminate in a wet state can be charged into the mold.

Next, an elastic core similar to the elastic core used in the sheet-making step can be inserted into the fiber laminate, a pressurized fluid can be supplied into the elastic core to expand the elastic core, and the expanded elastic core can press the fiber laminate against the inner face of the cavity. An elastic core surface-modified with a fluororesin, a silicone resin, or the like may be used. The supply pressure of the pressurized fluid can be the same as that of the dehydration step. Under this condition, the fiber laminate can be heated and dried, and the intermediate molded body can be dried and molded.

The heating temperature (mold temperature) of the mold for drying and molding can be preferably 100° C. or more and 300° C. or less, more preferably 150° C. or more and 250° C. or less, and even more preferably 190° C. or more and 240° C. or less, for instance, from the viewpoint of improving the surface properties and/or the viewpoint of shortening drying time. The heat treatment time may not be able to be generalized because the heat treatment time can vary depending on the heating temperature. From the viewpoint of improving the quality and the productivity, for instance, the heat treatment time can be preferably 0.5 minutes or more and 30 minutes or less and more preferably 1 minute or more and 10 minutes or less. When the heating temperature is 300° C. or less, the surface properties of the intermediate molded body can be regarded as good. When the heating temperature is 100° C. or more, the drying time of the intermediate molded body can also be shortened.

When the fiber laminate is sufficiently dried, the pressurized fluid in the elastic core can be taken out, and the core can be shrunk and taken out from the fiber laminate. Then, the mold can be opened, and the intermediate molded body can be taken out. The intermediate molded body can be used as the main body 20 by the curing of a thermosetting resin by the heat treatment.

The main body 20 thus obtained can be pressed by the elastic core, and therefore the inner face and the outer face can have high smoothness. Therefore, the molding accuracy can be regarded as high, and thus a structure having high accuracy can be obtained even when the structure has joints or threaded parts. Accordingly, the structures coupled with the joints or the threaded parts can enable the molten metal to smoothly flow through the inside of the structures. Further, the heat shrinkage ratio of the main body 20 in casting can be less than 5%, and therefore the leakage of the molten metal due to cracks, deformation, and the like of the structures can be prevented without any problem.

The obtained intermediate molded body can be further partially or entirely impregnated with the first binder. On the other hand, when the intermediate molded body is impregnated with the first binder and is not dipped in the raw material slurry, the treatment of the raw material slurry or white water may be simplified. When a thermosetting binder is used as the first binder, the thermosetting binder can be thermally cured by heating and drying the intermediate molded body at a predetermined temperature, completing the production of the main body 20.

Although the present disclosure describes preferable embodiments and aspects thereof, the present disclosure is not limited to the above-described embodiments and aspects. The above-described embodiments and modifications thereof can be combined insofar as their contents do not contradict each other. For example, the structure for producing a casting of one or more embodiments the present disclosure may have both the outside cover layer 32 of the female joint 12 and the outside cover layer 36 of the male joint 13.

Hereinafter, one or more embodiments of the present disclosure are detailed in more detail based on Examples, but the present disclosure is not limited to Examples below.

Example 1

The structure 1 shown in FIG. 9 was produced by the above-described production method, and was used as a structure for producing a casting of Example 1. The composition of the structure for producing a casting of Example 1 is as shown in Table 1 and is as described below. Specifically, the cover layer contained 1.25 parts by mass of attapulgite and 5 parts by mass of colloidal silica based on 100 parts by mass of zircon. The main body contained 10.2 parts by mass of waste newspaper, 8.5 parts by mass of carbon fibers, 66 parts by mass of spherical silica, and 15.3 parts by mass of phenol resin when the total of all the components was set to 100 parts by mass.

• • Zircon: Zircosil No. 1 manufactured by HAKUSUI TECH.
  • Attapulgite: Attagel 50 manufactured by Hayashi Kasei Co., Ltd.
  • Colloidal silica: Snowtex 50 manufactured by Nissan Chemical Corporation
  • Carbon fibers: TORAYCA chopped fibers manufactured by Toray Industries, Inc.
  • Spherical silica: S85-P manufactured by Micron Co., Ltd.
  • Phenol resin: Bell Pearl S890 manufactured by AIR WATER PERFORMANCE CHEMICAL INC.

The male joint had an inner diameter of 99.4 mm and an outer diameter of 102.4 mm. The thickness T2 of the female joint inside cover layer was 0.1 mm, the thickness T3 of the body inside cover layer was 0.3 mm, and the thickness T1 of the portion where the female joint inside cover layer and the body inside cover layer overlapped with each other was 0.4 mm.

Example 2

The structure 1 shown in FIG. 1 was produced by the above-described production method, and was used as a structure for producing a casting of Example 2. In the female joint applying step, the coating composition 70 was applied to the outer face of the female joint 12 by applying the coating composition 70 to the outer face of the female joint 12 with a brush or the like. The composition of the structure for producing a casting of Example 2 is the same as that of the structure for producing a casting of Example 1.

Comparative Example 1

A structure for producing a casting was produced in the same manner as Example 1, except that the female joint applying step was not performed.

TABLE 1
				Comp.
		Ex. 1	Ex. 2	Ex. 1
Presence or absence of female joint inside cover layer	Presence	Presence	Absence
Presence or absence of female joint end face cover part	Presence	Absence	Absence
Presence or absence of female joint outside cover layer	Presence	Presence	Absence
Female joint	Inner diameter (mm)	102.5	102.5	102.7
	Outer diameter (mm)	105.3	105.3	105.1
Presence or absence of leakage	Absence	—	Presence

[Evaluation of Presence or Absence of Leakage of Molten Metal in the Pouring of Molten Metal]

With respect to each of the structures for producing a casting of Example 1 and Comparative Example 1, the cylindrical bodies for producing a casting were coupled to produce cylindrical bodies. Then, molten metal was poured into a sand mold having each cylindrical body as a runner pipe to produce a casting. For the molten metal, 5 tons of carbon steel casting SC450 (JIS classification) was used. Then, the surface of each cylindrical body remaining after the solidification of the molten metal was visually observed, and the cut surfaces of the joints were observed. A case where the sand mold and the metal inside the cylindrical body were able to be separated without the leakage of the molten metal from the cylindrical body was evaluated as “No leakage.” A case where the molten metal leaked out from the cylindrical body and the casting sand of the sand mold partially causes metal penetration was evaluated as “Leakage occurred”.

As shown in Table 1, the leakage of the molten metal occurred in Comparative Example 1. In contrast thereto, the leakage of the molten metal did not occur in Example 1. Therefore, it is found that the structure for producing a casting according to one or more embodiments of the present disclosure can suppress the metal penetration caused by the leakage from the joints.

INDUSTRIAL APPLICABILITY

The structure for producing a casting according to one or more embodiments of the present disclosure can prevent the leakage of molten metal in the pouring of the molten metal.

The method for producing a structure for producing a casting according to one or more embodiments of the present disclosure can efficiently produce a structure for producing a casting capable of preventing the leakage of molten metal in the pouring of the molten metal

Embodiments of the disclosed subject matter can also be as set forth according to the following parentheticals.

• • (1) A cylindrical structure for producing a casting comprising a cylindrical main body, wherein the cylindrical main body comprises a body part, and
  • a female joint consecutively connected to the body part and having an inner diameter equal to or larger than an outer diameter of the body part, and the cylindrical structure comprises a body inside cover layer covering an inner face of the body part, and
  • an outside cover layer covering an outer face of the female joint.
  • (2) The structure for producing a casting according to (1), wherein the outside cover layer covers an entire region of the outer face of the female joint.
  • (3) The structure for producing a casting according to (1) or (2), comprising: a female joint inside cover layer covering an inner face of the female joint.
  • (4) The structure for producing a casting according to any one of (1) to (3), wherein the female joint inside cover layer and the body inside cover layer are continuous.
  • (5) The structure for producing a casting according to any one of (1) to (4), wherein the female joint inside cover layer extends to the inner face of the body part, and partially overlaps with the body inside cover layer.
  • (6) The structure for producing a casting according to any one of (1) to (5), wherein the female joint inside cover layer is arranged on an inner side relative to the body inside cover layer, in a radial direction of the structure for producing a casting in a portion where the female joint inside cover layer and the body inside cover layer overlap with each other.
  • (7) The structure for producing a casting according to any one of (1) to (6), wherein the portion, where the female joint inside cover layer and the body inside cover layer overlap with each other, has a thickness larger than both thicknesses of a portion having a largest thickness in the female joint inside cover layer and a portion having a largest thickness in the body inside cover layer.
  • (8) The structure for producing a casting according to any one of (1) to (7), wherein the female joint inside cover layer covers an entire region of the inner face of the female joint, and the body inside cover layer covers an entire region of the inner face of the body part.
  • (9) The structure for producing a casting according to any one of (1) to (8), wherein a position of an edge of the female joint inside cover layer on a proximal end side in a consecutively connecting direction of the female joint coincides with a position of an edge of the outside cover layer on a proximal side in the consecutively connecting direction of the female joint.
  • (10) The structure for producing a casting according to any one of (1) to (9), comprising: an end face cover part covering an end face of the female joint.
  • (11) The structure for producing a casting according to any one of (1) to (10), comprising: a female joint inside cover layer covering an inner face of the female joint; and an end face cover part covering an end face of the female joint, wherein the end face cover part and the female joint inside cover layer are continuous.
  • (12) The structure for producing a casting according to any one of (1) to (11), wherein the outside cover layer extends to the inner face of the body part through an end face of the female joint.
  • (13) The structure for producing a casting according to any one of (1) to (12), comprising a female joint inside cover layer covering an inner face of the female joint, wherein the female joint inside cover layer has a thickness smaller than thicknesses of the cover layers other than the female joint inside cover layer.
  • (14) The structure for producing a casting according to any one of (1) to (13), wherein an end part of the structure for producing a casting other than the female joint has an outer diameter equal to or smaller than the inner diameter of the female joint.
  • (15) The structure for producing a casting according to any one of (1) to (14), wherein
    • an outer diameter of the female joint is the largest among outer diameters of the structure for producing a casting, and
    • the inner diameter of the female joint is the largest among inner diameters of the structure for producing a casting.
  • (16) The structure for producing a casting according to any one of (1) to (15), wherein an inner diameter of an end part of the structure for producing a casting other than the female joint is 100 mm or more.
  • (17) A cylindrical structure for producing a casting comprising a cylindrical main body, wherein the cylindrical main body comprises a body part, and a male joint in one end part of the body part, the male joint is to be internally joined to a female joint, the male joint has an outer diameter equal to or smaller than an inner diameter of the female joint, and the cylindrical structure comprises a body inside cover layer covering an inner face of the body part, and an outside cover layer covering an outer face of the male joint.
  • (18) The structure for producing a casting according to (17), comprising an end face cover part covering an end face of the male joint.
  • (19) The structure for producing a casting according to (17) or (18), wherein the end face cover part and the outside cover layer are continuous.
  • (20) The structure for producing a casting according to any one of (17) to (19), wherein
    • the main body has a female joint consecutively connected to the body part and having an inner diameter equal to or larger than an outer diameter of the body part, and
    • the outer diameter of the male joint is equal to or smaller than the inner diameter of the female joint consecutively connected to the body part.
  • (21) The structure for producing a casting according to any one of (17) to (20), wherein an outer diameter of the female joint is the largest among outer diameters of the structure for producing a casting, and the inner diameter of the female joint is the largest among inner diameters of the structure for producing a casting.
  • (22) The structure for producing a casting according to any one of (17) to (21), wherein the body inside cover layer covers an entire region of the inner face of the body part.
  • (23) The structure for producing a casting according to any one of (17) to (22), wherein the male joint has an inner diameter of 45 mm or more and 700 mm or less, preferably 65 mm or more and 550 mm or less, and even more preferably 90 mm or more and 350 mm or less.
  • (24) The structure for producing a casting according to any one of (17) to (23), wherein the body inside cover layer is arranged on an innermost side in the radial direction of the structure for producing a casting in a portion where the body inside cover layer is arranged.
  • (25) The structure for producing a casting according to any any one of (17) to (24), wherein the outside cover layer is arranged on an outermost side in the radial direction of the structure for producing a casting.
  • (26) The structure for producing a casting according to any one of (17) to (25), wherein the main body has a single layer structure.
  • (27) The structure for producing a casting according to any one of (17) to (26), wherein the main body is integrally molded in a circumferential direction of the main body.
  • (28) The structure for producing a casting according to any one of (17) to (27), comprising a body outside cover layer covering an outer face of the body part.
  • (29) The structure for producing a casting according to any one of (17) to (28), wherein the body outside cover layer is continuous over an entire circumference in the circumferential direction of the structure for producing a casting.
  • (30) A method for producing a cylindrical structure for producing a casting, wherein the structure for producing a casting comprises a cylindrical main body, the cylindrical main body comprises a body part, and a female joint consecutively connected to the body part in axial direction, the female joint has an inner diameter equal to or larger than an outer diameter of the body part, and the method comprises: a body part applying step where a coating composition is applied to an inner face of the body part to form a body inside cover layer covering the inner face of the body part; and a female joint applying step where a coating composition is applied to an outer face of the female joint over an entire circumference of the female joint to form an outside cover layer covering the outer face of the female joint.
  • (31) The method for producing a structure for producing a casting according to (30), wherein, in the body part applying step, the coating composition is applied by pouring the coating composition into the body part from an end part side of the body part other than an end part on a side of the female joint.
  • (32) The method for producing a structure for producing a casting according to (30) or (31), wherein, in the female joint applying step, the coating composition is applied to an inner face of the female joint over the entire circumference of the female joint to form a female joint inside cover layer covering the inner face of the female joint.
  • (33) The method for producing a structure for producing a casting according to any one of (30) to (32), wherein, in the female joint applying step, the coating composition is applied by dipping the female joint in the coating.
  • (34) The method for producing a structure for producing a casting according to any one of (30) to (33), wherein the female joint applying step is performed after the body part applying step.
  • (35) A method for using a structure for producing a casting, comprising using the structure for producing a casting according to any one of (1) to (34) as a runner or a strain relief runner in casting of cast steel.
  • (36) A method for producing a mold for cast steel, comprising embedding the structure for producing a casting according to any one of (1) to (35) in casting sand leaving a part of opening parts of the structure for producing a casting.
  • (37) A method for producing a cast steel casting, comprising: a mold production step of producing a mold by embedding the structure for producing a casting according to any one of claims 1 to 29 in casting sand leaving a part of opening parts of the structure for producing a casting; and a casting step of pouring molten metal into the mold.

It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. That is, unless clearly specified otherwise, as used herein the words “a” and “an” and the like carry the meaning of “one or more.” The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B” or one or more of A and B″) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B; A, A and B; A, B and B), unless otherwise indicated herein or clearly contradicted by context. Similarly, as used herein, the word “or” refers to any possible permutation of a set of items. For example, the phrase “A, B, or C” refers to at least one of A, B, C, or any combination thereof, such as any of: A; B; C; A and B; A and C; B and C; A, B, and C; or multiple of any item such as A and A; B, B, and C; A, A, B, C, and C; etc.

Additionally, it is to be understood that terms such as “left,” “right,” “top,” “bottom,” “front,” “rear,” “side,” “height,” “length,” “width,” “upper,” “lower,” “interior,” “exterior,” “inner,” “outer,” and the like that may be used herein, merely describe points of reference and do not necessarily limit embodiments of the disclosed subject matter to any particular orientation or configuration. Furthermore, terms such as “first,” “second,” “third,” etc., merely identify one of a number of portions, components, points of reference, operations and/or functions as described herein, and likewise do not necessarily limit embodiments of the disclosed subject matter to any particular configuration or orientation.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, assemblies, systems, and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

1. A cylindrical structure for producing a casting comprising a cylindrical main body, wherein the cylindrical main body includes: a body part, anda female joint consecutively connected to the body part and having an inner diameter equal to or larger than an outer diameter of the body part, andthe cylindrical structure comprises: a body inside cover layer covering an inner face of the body part of the cylindrical main body, andan outside cover layer covering an outer face of the female joint of the cylindrical main body.

2. The structure for producing a casting according to claim 1, wherein the outside cover layer covers an entire region of the outer face of the female joint.

3. The structure for producing a casting according to claim 1, further comprising: a female joint inside cover layer covering an inner face of the female joint.

4. The structure for producing a casting according to claim 3, wherein the female joint inside cover layer and the body inside cover layer are continuous.

5. The structure for producing a casting according to claim 3, wherein the female joint inside cover layer extends to the inner face of the body part, and partially overlaps with the body inside cover layer.

6. The structure for producing a casting according to claim 5, wherein the female joint inside cover layer is arranged on an inner side relative to the body inside cover layer, in a radial direction of the structure for producing a casting in a portion where the female joint inside cover layer and the body inside cover layer overlap with each other, and/orthe portion, where the female joint inside cover layer and the body inside cover layer overlap with each other, has a thickness larger than both thicknesses of a portion having a largest thickness in the female joint inside cover layer and a portion having a largest thickness in the body inside cover layer.

7. The structure for producing a casting according to claim 3, wherein the female joint inside cover layer covers an entire region of the inner face of the female joint, andthe body inside cover layer covers an entire region of the inner face of the body part.

8. The structure for producing a casting according to claim 1, further comprising: an end face cover covering an end face of the female joint.

9. The structure for producing a casting according to claim 1, further comprising: a female joint inside cover layer covering an inner face of the female joint; andan end face cover covering an end face of the female joint,wherein the end face cover and the female joint inside cover layer are continuous.

10. The structure for producing a casting according to claim 1, wherein the outside cover layer extends to the inner face of the body part through an end face of the female joint.

11. The structure for producing a casting according to claim 1, wherein an end part of the structure for producing a casting other than the female joint has an outer diameter equal to or smaller than the inner diameter of the female joint,an outer diameter of the female joint is the largest among outer diameters of the structure for producing the casting, and the inner diameter of the female joint is the largest among inner diameters of the structure for producing the casting.

12. A cylindrical structure for producing a casting comprising a cylindrical main body, wherein the cylindrical main body includes: a body part, anda male joint in one end part of the body part,the male joint is to be internally joined to a female joint,the male joint has an outer diameter equal to or smaller than an inner diameter of the female joint, and the cylindrical structure comprises:a body inside cover layer covering an inner face of the body part of the cylindrical main body, andan outside cover layer covering an outer face of the male joint of the cylindrical body.

13. The structure for producing a casting according to claim 12, further comprising an end face cover covering an end face of the male joint.

14. The structure for producing a casting according to claim 13, wherein the end face cover and the outside cover layer are continuous.

15. The structure for producing a casting according to claim 13, wherein the main body has a female joint consecutively connected to the body part and having an inner diameter equal to or larger than an outer diameter of the body part,the outer diameter of the male joint is equal to or smaller than the inner diameter of the female joint consecutively connected to the body part,an outer diameter of the female joint is the largest among outer diameters of the structure for producing the casting, and the inner diameter of the female joint is the largest among inner diameters of the structure for producing the casting.

16. The structure for producing a casting according to claim 13, wherein the body inside cover layer covers an entire region of the inner face of the body part.

17. A method for producing a cylindrical structure for producing a casting, wherein the structure for producing a casting comprises a cylindrical main body,the cylindrical main body includes: a body part, anda female joint consecutively connected to the body part in an axial direction,the female joint has an inner diameter equal to or larger than an outer diameter of the body part, andthe method comprises: applying a first coating composition to an inner face of the body part to form a body inside cover layer covering the inner face of the body part; andapplying a second coating composition to an outer face of the female joint over an entire circumference of the female joint to form an outside cover layer covering the outer face of the female joint.

18. The method for producing a structure for producing a casting according to claim 17, wherein the first coating composition is applied by pouring the first coating composition into the body part from an end part side of the body part other than an end part on a side of the female joint, andthe second coating composition is applied to an inner face of the female joint over the entire circumference of the female joint to form a female joint inside cover layer covering the inner face of the female joint.

19. The method for producing a structure for producing a casting according to claim 18, wherein the second coating composition is applied by dipping the female joint in the second coating composition.

20. The method for producing a structure for producing a casting according to claim 17, wherein the second coating composition is applied after the application of the first coating composition.