JPH01236A - Method for manufacturing fluid permeable castings - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for manufacturing a fluid-permeable cast product, and in particular, the present invention relates to a method for producing a fluid-permeable cast product, and in particular, a method for manufacturing a cast product that has continuous pores and has the property of allowing fluid to permeate through a metallurgical or mechanical process. The present invention relates to an improvement in a manufacturing method that can be advantageously produced without additional treatment.

(Background Art) The applicant has previously proposed a method for advantageously manufacturing a cast product having continuous pores and the property of allowing fluid to pass therethrough without adding any metallurgical or mechanical treatment. , Japanese Patent Application No. 61-246360, Japanese Patent Application No. 62-6925, etc., a ceramic material attached around the skeleton of a structure such as a three-dimensional network structure is sintered, and such a skeleton structure is While the three-dimensional network structure is maintained by sintering the adhered ceramic material, which is obtained by eliminating the material constituting the Using a ceramic porous body in which pores are formed in the skeleton,
With this ceramic porous body placed in the casting cavity of a predetermined mold, a predetermined molten metal is poured as a matrix material, penetrates into the gaps in the three-dimensional network structure, solidifies, and forms an integral part. We have clarified a method for manufacturing a cast product that allows fluid to pass through by making use of the pores formed in the skeleton of the three-dimensional mesh structure of the ceramic porous body.

By the way, in the manufacturing method of such a fluid-permeable cast product, the flow of the molten metal poured into the three-dimensional network structure of the ceramic porous body placed in the casting cavity of the mold is poor ( In particular, this problem becomes more pronounced when a porous ceramic body with a small network structure is used, and as a result, the problem arises that the molten metal does not spread throughout the porous ceramic body, reducing the quality of the intended cast product. Further studies by the present inventors have revealed that, at the very least, the product yield is lowered or the product cannot be used for its intended purpose.

The reason for this is that the wettability between the ceramic porous body and the molten metal is not good.2) When the distance between the skeletons of the three-dimensional network structure becomes narrower, the clogging of the three-dimensional network structure increases when the ceramic material is attached. This leads to increased clogging of the porous ceramic body, resulting in poor flow of the metal. In a fluid-permeable cast product, the proportion of the porous ceramic body that provides fluid permeability properties is too large. Casting Examples include that the plan is inappropriate.

Countermeasures against these causes include (a) improving wettability for molten metal by changing the ceramic material that makes up the ceramic porous body, and (b) creating a uniform ceramic network by changing the ceramic material. (C) to form a structural skeleton; (C)
Ideas include raising the temperature of the porous ceramic body before casting, (d) changing the casting method by installing a riser, and (e) improving the fluidity of the molten metal. It will be done.

However, none of these measures can fully achieve their objectives, such as (a) and (a) above.
It is difficult to expect a clear effect from the measure (b), and the measure (c) also causes a new problem of heat cracking in the porous ceramic body itself, and (d) In this countermeasure, the proportion of the ceramic porous material that provides fluid permeability in the cast product inevitably decreases, resulting in a cast product that is inefficient in terms of its intended use.

Furthermore, in order to improve the fluidity of the molten metal in the countermeasure (e), it is possible to raise the molten metal temperature or use additives, but this may be done by increasing the heat resistance and brittleness of the porous ceramic body. The problem is that

(Object of the Invention) The present invention has been made against the background of the above-mentioned circumstances, and its object is to provide a cast product having continuous pores and having the property of being able to permeate fluid. The purpose is to provide an improved method that can advantageously produce ceramics without metallurgical or mechanical processing, and other purposes include improving the quality of ceramic materials, casting methods, etc. Even if a small ceramic porous body is used between the skeletons without changing the structure, or even if the proportion of the ceramic porous body portion in the cast product is increased, it is not necessary to adopt measures such as a riser. The objective is to improve the flow of hot water into the three-dimensional network structure of a ceramic porous body.

(Structure of the invention) In order to achieve such an object, the present invention has the following features:
The attached ceramic material is obtained by sintering the ceramic material attached around the skeleton of the skeletal structure of the three-dimensional network structure made of the fugitive material, and at the same time causing the fugitive material constituting the skeletal structure to disappear. While the three-dimensional network structure is maintained by sintering, the skeleton of the three-dimensional network structure itself is hollow, and continuous pores are formed in the skeleton as a whole. By injecting a predetermined molten metal as a matrix into the gaps of the three-dimensional network structure and solidifying it to form an integral structure, the voids formed within the skeleton of the three-dimensional network structure of the ceramic porous body are When manufacturing a cast product that allows fluid to pass through using holes,
Prior to casting the molten metal, a metal coating layer of a predetermined thickness is formed around the skeleton of the three-dimensional network structure in the porous ceramic body, so that the surface of the skeleton does not come into direct contact with the molten metal. I made it.

(Specific Structure/Example) By the way, when manufacturing a desired fluid-permeable cast product according to the method of the present invention, for example, as shown in FIG. in place, the second
By pouring a predetermined molten metal into a ceramic porous body having a specific structure as shown in the figure, a three-dimensional continuous structure as shown in Figures 3 to 5 is created. The desired cast product is manufactured, which has pores (voids) and has the property of being able to permeate fluid.

In FIG. 1, reference numeral 10 denotes a mold composed of an upper mold 12 and a lower mold 14. Generally, self-hardening mold making using green sand or resin as a hardening medium is a permanent mold (metallic mold). It was manufactured using a mold (type) etc. Further, a casting cavity 20 having a predetermined shape is formed in the mold 10, and a ceramic porous body 22 according to the present invention having a predetermined three-dimensional network structure is set in the cavity 20. be.

A pool 24 is provided around the ceramic porous body 22 set in the cavity 20, and a predetermined molten metal 26 is fed from a ladle 28 to a molten metal inlet 3.
The hot water will be poured through 0.

Further, in FIG. 1, the porous ceramic body 22 is placed on the bottom surface of the casting cavity 20 in order to obtain a cast product in which the surface of the porous ceramic body 2205 in the shape of a rectangular parallelepiped is surrounded by cast metal of a predetermined thickness. Furthermore, as shown in FIG.
When obtaining a product in which the ceramic porous body 22 is cast, the ceramic porous body 22 is placed and set so as to cover the entire inside of the casting cavity 20, and in this way, the ceramic porous body 22 in the cast product is The arrangement position of the body 22 and its shape are not limited to the number of ships;
It is determined as appropriate depending on the intended product.
For example, if the ceramic porous body 22 is to be inserted with some of its outer circumferential surfaces floating above the inner surface of the casting cavity 20, a suitable fastener such as a keren will be used in accordance with a conventional method.

Here, the ceramic porous body 22 having a three-dimensional network structure according to the present invention, which is placed and fixed in the cavity 20, is first constructed using a skeletal structure of a three-dimensional network structure made of a predetermined fugitive material such as a synthetic resin. A predetermined ceramic material is attached around the skeleton and sintered, and the fugitive material constituting the skeletal structure is made to disappear at the same time as sintering or separately with a solvent, etc., thereby eliminating the adhesion. While the three-dimensional network structure is maintained by sintering the ceramic material, the skeleton of the three-dimensional network structure itself is hollow, and continuous pores are formed within the skeleton as a whole. This can then be obtained by further forming a metal coating layer of a predetermined thickness around the skeleton of the three-dimensional network structure of the porous ceramic material, as described below.

The ceramic material to be attached to the surface of the skeleton of the three-dimensional network structure made of such a predetermined fugitive material may include cordierite, alumina, Known materials such as alumina cordierite, silicon carbide, mullite, and zirconia are appropriately selected and employed.

By the way, the three-dimensional network structure made of synthetic resin, which provides the material for the basic three-dimensional network structure of the ceramic porous body 22, is generally made by foaming a synthetic resin such as ester-based polyurethane, and then forming its skeleton. The film-like substance (foamed PL; 4) remaining around the is removed according to a known method.
A synthetic/synthetic resin foam having a three-dimensional network structure obtained by removal using compressed air or the like will be advantageously used. In addition, foaming in resin foams such as polyurethane foam is performed by the action of gas such as carbon dioxide gas generated by chemical reaction and/or evaporated gas of a volatile blowing agent, thereby forming a foam of a specified resin material. A large number of spherical bubbles are formed inside the foam, and the resin portions between these bubbles form a three-dimensional network skeleton structure in the shape of a dodecahedron. Because a thin film of material such as polyurethane is attached around the skeleton, the thin film other than the skeleton must be removed using known methods such as heat treatment, dissolution with a solvent, and removal using water pressure (water jet). becomes.

Next, the thus obtained three-dimensional network structure is further impregnated and adhered with a predetermined ceramic material in a slurry state according to a known method, and the excess slurry is removed and further dried. After sintering, a firing operation corresponding to the deposited ceramic material is performed, so that the skeleton made of fugitive material such as synthetic resin is burned out or removed, either simultaneously with the sintering of the ceramic material or separately. As a result, pores 36 corresponding to the shape are formed in the three-dimensional network structure skeleton 34 made of the sintered ceramic material, as shown in FIG. It will become.

In the present invention, the ceramic porous material having such a three-dimensional network structure is prepared in the manner shown in FIGS. 6(a) and (
As shown in b), a metal coating layer 35 of a predetermined thickness is formed on the surface of the skeleton 34, and the molten metal 26 is poured.
The metal coating layer 35 is coated around the skeleton 34 of the porous ceramic material according to various known methods, so that the surface of the skeleton 34 is coated with molten metal. Although the metal coating layer 35 is formed so as not to come into direct contact with the metal coating layer 26, preferably, such a metal coating layer 35 is composed of a plating layer formed according to a normal electroless plating method. .

As is well known, in this electroless plating method, the ceramic porous material is degreased with caustic soda, etc., then conditioned, and then subjected to a catalytic process and an activation process, and then the desired plating process is performed. It can be easily carried out by depositing metals (including alloys) on the surface of the skeleton of the skeletal structure of the porous ceramic material by electroless plating, and thereby metals such as nickel, cobalt, palladium, etc. A plating layer of a predetermined thickness made of metals, alloys based on them, or metals such as copper, silver, and gold is formed as a metal coating layer 35 so as to cover the skeleton 34 of the porous ceramic material. It is.

Further, the thickness of the metal coating layer 35 formed around the skeleton 34 of the porous ceramic material is selected depending on the purpose, but generally, the thickness is at least 0.5 mm. It is desirable to have a thickness of 5 μm; for example, in the above-mentioned electroless plating method, a plated layer with a thickness of 0.5 μm to 2 μm is formed on the surface of the skeleton. Furthermore, by using a normal electrolytic plating method in combination with such an electroless plating method, it is possible to further increase the thickness of the metal film layer 35, for example, a thickness of several tens of μm. A metallization layer can be formed. The metals to be electroplated include various known metals such as nickel, chromium, zinc, cadmium, tin, lead, iron, copper, silver, gold, and alloys thereof, depending on the purpose. It will be selected as appropriate. In particular, if the thickness of the metal coating layer 35 is increased so that its surface layer penetrates into the molten metal, it becomes possible to modify the matrix metal.

As described above, the ceramic porous body 22 in which the metal coating layer 35 of a predetermined thickness is formed around the skeleton 34 is placed in the casting cavity 20 to form a cast product. A molten metal 26 having chemical components controlled according to the physical properties required for the process is poured. Although the molten metal 26 is generally made of cast iron or cast steel, the present invention can also be advantageously applied to the casting of various metal products such as copper alloys and aluminum alloys. Therefore, it goes without saying that the molten metal 26 is appropriately selected depending on the raw material for the product.

Moreover, the molten metal 26 poured in this way is generally
As shown in FIG. 1, it is introduced into the casting cavity 20 through the inlet 30 and the runner 16, and fills the gap between the three-dimensional network structure skeleton 34 of the ceramic porous body 22 set therein. However, in that case,
On the surface of the skeleton 34 of the ceramic porous body 22,
As shown in FIG. 6(b), a metal coating layer 35 of a predetermined thickness is formed, and the surface of the skeleton 34 is covered with the molten metal 2.
In other words, the affinity (wettability) between the porous ceramic body 22 and the molten metal 26 is improved due to the presence of the metal coating layer 35. The vortex flow is good, and therefore the molten metal 26 can be effectively circulated throughout the porous ceramic body 22, thereby effectively resolving the problem of reduced product yield due to poor molten metal circulation. I ended up getting it.

As mentioned above, this molten metal 26 is not limited to non-ferrous or ferrous metals, but when it is introduced into the casting cavity 20, a drop in temperature due to contact with the inner wall surface of the mold 10 is unavoidable. By installing the ceramic porous body 22,
Since this tendency will be exacerbated, it is desirable to set the molten metal temperature at the time of pouring to be higher than normal. Further, according to the present invention, the metal coating layer 3
5, the molten metal 26 can be advantageously introduced between the skeletal structures (inside the cells) of the porous ceramic body 22,
Although it is possible to solidify the molten metal, if necessary, an appropriate amount of feeder may be set to provide an appropriate molten metal head, but in the present invention, such a molten metal head can be effectively It can be done as low as possible.

After the pouring of the molten metal 26 is completed, the molten metal 26 is solidified, and the solidified cast product is as shown in FIGS. 3 and 4. Then, the cast metal 40 enters into the cell constituted by the skeleton 34 having a three-dimensional network structure of the ceramic porous body 22, and the cast metal 40 enters the ceramic porous body 22.
The result is an integrated structure consisting of a matrix for the elements.

Furthermore, after the solidification of such cast products is completed,
The desired finished cast product 32 is obtained through the same processes as in normal casting work, such as cracking, cooling, cleaning by shot blasting, etc., and finishing with a grinder. In this case, since the openings of the holes 36 in the exposed surface 38 of the skeleton 34 of the ceramic porous body 22 buried therein are closed with the cast metal 40, the exposed surface 38 is not subjected to cutting or other processing. By performing the polishing process, the holes 36 are opened to the outside, and as a result, a fine three-dimensional network structure is formed inside as shown in FIGS. 3 to 5. The desired cast product 32 can be obtained, which has continuous pores and has the property of being able to permeate fluid.

The above is based on a specific example of manufacturing a fluid-permeable cast product.
Although the present invention has been described in detail, it goes without saying that the present invention is not to be construed as being limited only to the description of such specific examples and specific configurations related thereto.

For example, in clay figurines, a synthetic resin foam from which the foam membrane has been removed, to which the present invention can be advantageously applied, is used as a three-dimensional network structure of synthetic resin that provides a ceramic porous body, in particular polyurecne foam. However, any number of three-dimensional network structures manufactured by other methods and made of suitable fugitive materials such as synthetic resins may be used.

In addition, although not listed, the present invention can be implemented in embodiments with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and such embodiments include: It should be understood that any such modifications are included within the scope of the present invention as long as they do not depart from the spirit of the present invention.

(Effects of the Invention) As is clear from the above description, according to the present invention, when manufacturing a fluid-permeable cast product that integrally incorporates a porous ceramic body with a three-dimensional network structure, the structure of the porous ceramic body Since a metal coating layer of a predetermined thickness is formed around the tissue skeleton, the poured molten metal does not come into direct contact with the ceramics, and the metal coating layer increases the affinity with the molten metal ( Therefore, the vortex flow is good, and therefore the water circulation can be improved, and the water can effectively penetrate between the skeletal structures of the entire porous ceramic body, thereby achieving the purpose. This enabled us to advantageously improve the quality of fluid-permeable cast products and, in turn, improve the yield.Also, by improving the flow of the molten metal, we were able to advantageously adopt a method with a lower molten metal head. It is.

Furthermore, according to the present invention, by improving the flow of hot water, it is possible to set a large proportion of the ceramic porous body in the cast product, and thereby, when the entire surface of the cast product is made fluid permeable, There is also the advantage of being able to lower the machining ratio, and even if a fine ceramic porous body is used, it is difficult to cause poor molten metal circulation (furthermore, aluminum castings and bronze castings, which were considered difficult to circulate, etc.) It has become possible to obtain sound cast products even in

Furthermore, according to the present invention, since a metal coating layer of a predetermined thickness is formed around the skeleton of the porous ceramic body, the strength of the porous ceramic body itself is improved, making it easier to handle during casting work. On the other hand, problems such as skeleton defects can be effectively prevented, and the quality of the obtained fluid-permeable cast product can be advantageously improved.Furthermore, by forming such a metal coating layer, ceramic porous The problem is that the quality of the molten metal, which is a matrix component, deteriorates due to the elution of components from the body. Problems such as performance deterioration can be advantageously resolved.

In addition, the fluid-permeable cast product obtained according to the method of the present invention as described above has fine continuous pores having a three-dimensional network structure inside, and has the property of being able to permeate fluid. Products with such characteristics have not been seen in the past, and depending on the purpose of use, fluids such as air, gas, water, hot water, or oil can freely pass through the pores. Since it can be used in a wide variety of materials that take advantage of its properties.

Further, according to the method of the present invention, the desired fluid-permeable product can be advantageously manufactured with good productivity without adding any metallurgical or mechanical treatment and according to the same conventional method. It goes without saying that it is possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing one step of the manufacturing method according to the present invention, FIG. 2 is an enlarged cross-sectional view of the main part showing the ceramic porous body used therein, and FIG. FIG. 4 is an enlarged sectional explanatory view of a main part showing a cast product obtained by such a manufacturing method, FIG. 4 is an enlarged explanatory view of the cast product in FIG. 3, and FIG. 5 is an overall perspective view of the cast product. It is. Further, FIG. 6(a) is an explanatory cross-sectional view showing an enlarged part of the skeleton of the porous ceramic material on which the metal coating layer is formed with a predetermined thickness, and FIG. 6(b) is
It is an explanatory enlarged cross-sectional view of a main part showing a state in which a predetermined metal coating layer is formed around such a skeleton. 10: Mold 20: Casting cavity 22: Porous ceramic body 26: Molten metal 34: Skeleton 35: Metal coating layer 36: Hole 40: Casting metal Applicant Subeya Co., Ltd. No. 3121 Figure 4 Figure 5 (a) Figure 3(b)

Claims (5)

[Claims] (1) The above-mentioned method obtained by sintering a ceramic material attached around the skeleton of a skeletal structure of a three-dimensional network structure made of a fugitive material and causing the fugitive material constituting the skeletal structure to disappear. While the three-dimensional network structure is maintained by sintering the adhered ceramic material, the skeleton of the three-dimensional network structure itself is made hollow, and continuous pores as a whole form the ceramic porous body formed within the skeleton. By injecting a predetermined molten metal as a matrix into the gaps in the three-dimensional network structure and solidifying it to form an integral structure, the voids formed within the skeleton of the three-dimensional network structure of the ceramic porous body are When manufacturing a cast product that allows fluid to pass through using pores, prior to casting the molten metal, a metal of a predetermined thickness is placed around the skeleton of the three-dimensional network structure in the porous ceramic body. 1. A method for manufacturing a fluid-permeable cast product, characterized in that a coating layer is formed so that the surface of the skeleton does not come into direct contact with the molten metal. (2) The manufacturing method according to claim 1, wherein the metal coating layer is a plating layer formed by at least electroless plating. (3) The manufacturing method according to claim 1 or 2, wherein the metal coating layer has a thickness of at least 0.5 μm. (4) The manufacturing method according to any one of claims 1 to 3, wherein the three-dimensional network structure is a polyurethane foam obtained by removing a foam membrane. (5) The manufacturing method according to any one of claims 1 to 4, wherein the molten metal is a molten cast iron or cast steel.