JPH0238055B2 - SUICHOKUIKOMIHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a vertical casting method, and particularly to a vertical casting method that advantageously removes metal oxides, non-metallic inclusions, etc. in the molten metal that is flowed into the casting cavity of a mold. The present invention relates to a method that allows casting products of excellent quality to be cast with good workability.

(Background technology/problems to be solved) Traditionally, when casting products such as cast iron products, an upper mold and a lower mold are used as molds.
The horizontal casting method has been adopted in which a specified amount of molten metal is introduced into a casting cavity formed by stacking them one on top of the other, and casting is performed. One method, known as the vertical casting method or the so-called disamatic molding method, involves stacking vertical molds horizontally to form a predetermined casting cavity between the molds, while pouring the metal from above. A method of introducing a molten metal into the casting cavity to form a desired cast product has been attracting attention.

More specifically, in such a vertical casting method, first, molding sand 4 supplied from a sand hopper 2 is compressed in a molding chamber 8 of a molding machine 6, as shown in FIGS. A high-density mold 10 is formed. In addition,
This mold 10 is generally shaped so that casting cavities 12 for producing a predetermined cast product are formed on both sides thereof, and as shown in FIG. 1c, these molds 10 are stacked horizontally. Mold 1 that fits next to
A predetermined casting cavity 12 is formed between 0 and 10. In other words, mold 1
The molds 10 are stacked horizontally so that the mating surfaces (parting lines) of 0 are substantially vertical, and a predetermined casting cavity 12 is formed between them.
0 are successively stacked on top of each other, casting cavities 1 are formed on both sides of one mold 10, respectively.
2 and 12 are formed. Then, the molten metal 16 in the ladle 14 is poured from above into the casting cavity 12 formed between the molds 10, 10, and the desired cast products 18 are successively cast. .

Therefore, in such a vertical casting method,
Since casting cavities are formed continuously on both sides of horizontally stacked molds, the amount of casting sand required for the number of products obtained is smaller than in horizontal casting methods, which reduces manufacturing costs. In addition, when overlapping molds to form a casting cavity, there is no need to invert the molds as in the horizontal casting method, but it is done by overlapping them horizontally. , the molding speed is fast,
This makes it possible to manufacture cast products with good productivity.

However, in such a vertical casting method, the molten metal 16 poured from above flows through the metal passage formed on the mating surfaces of the mold 10.
Since it is caused to flow down and is guided into the casting cavity 12, it is easy to entrain various foreign substances such as slag and foundry sand, thereby reducing the quality of the product or deteriorating the product yield. There are inherent problems such as nuisance.

However, in the case of the conventional horizontal casting method, it is relatively difficult to remove such foreign substances, such as metal oxides and non-metallic inclusions, by applying various measures inside the mold. Although easy, in the vertical casting method described above, it was extremely difficult to take such removal measures and clean the molten metal, and as a matter of course,
In order to modify the molten metal to be poured, it is not possible to carry out in-mold inoculation or in-mold graphite spheroidization methods in which an inoculant or a graphite spheroidizing agent is placed in the mold and inoculated into the molten metal. , is said to be extremely difficult.

On the other hand, the present inventor previously disclosed in Japanese Patent Application No. 60-59073 and No. 60-71845 that a ceramic porous body having a three-dimensional network skeleton structure having continuous pores was used, and the poured molten metal was After being brought into contact with an inoculant and a graphite spheroidizing agent, the porous ceramic body is guided into a casting cavity.
They have proposed an instant inoculation casting method or an instant spheroidization treatment method in a mold, and the ceramic porous body disclosed therein is set in the molten metal channel in the mold in the vertical casting method described above, and the molten metal is poured into a mold. By allowing it to pass through, it is possible to effectively prevent foreign substances such as slag and sand from being mixed into the resulting cast product, as well as undissolved inoculant and graphite nodularizing agent.

However, such a ceramic porous body having a three-dimensional network skeleton structure having continuous pores is partitioned into a molten metal passage formed on the mating surfaces of horizontally overlapping molds in the vertical casting method. When setting the ceramic porous body, the entire surface of the ceramic porous body has a porous structure, and therefore the surface has a jagged uneven surface. The molding sand constituting the mold is easily scraped off, so it is necessary to pay close attention to the setting of the ceramic porous body. This is because the foundry sand dropped during setting of the ceramic porous body is directly introduced into the casting cavity along with the molten metal, significantly reducing the quality of the resulting cast product.

(Solution/Operation) Here, the present invention has been made against the background of the above-mentioned circumstances, and its feature is that vertical molds are superimposed in the horizontal direction, and there is a gap between the molds. A ceramic porous body with a three-dimensional network skeleton structure having continuous pores is used to form a predetermined casting cavity, while guiding molten metal poured from above into the casting cavity to form the desired cast product. of,
One of the molds is housed in a bottomed cylindrical body that covers at least its side surfaces, has a molten metal passage hole at the bottom, and is provided with a flange-like protrusion projecting laterally, and forms a molten metal passage on the mating surface of the mold. After setting and holding the bottomed cylindrical body containing the ceramic porous body in the passage forming part of the mold in the cylindrical body part including the protrusion, the other mold is superimposed and the cylindrical body is placed between the two molds. A predetermined casting cavity and molten metal passage are formed, and the molten metal passage is partitioned by a ceramic porous body housed in the bottomed cylinder, so that the poured molten metal is It passes through the ceramic porous body and is guided into the casting cavity.

That is, in the present invention, a ceramic porous body having a three-dimensional network skeleton structure having continuous pores is not directly set in the molten metal passage of a mold, but such a ceramic porous body is set in a flange shape that projects laterally. In other words, when the ceramic porous body is accommodated in a bottomed cylinder provided with a protrusion, the jagged uneven portion on the circumferential surface of the ceramic porous body is covered with the bottomed cylinder so that it does not come into contact with the mold surface. The bottomed cylindrical body is set in one mold through its smooth surface, and the bottomed cylindrical body is well held in a predetermined position by a flange-like protrusion provided thereon. It is a thing,
This makes it possible to effectively prevent molding sand from being scraped off when setting the molds or overlapping the molds.

(Specific Description/Examples of Configuration) Hereinafter, the configuration of the present invention will be explained in more detail with reference to the embodiments shown in the drawings.

First, FIG. 2 is a partial view of the surface of a vertical mold 20 molded by a conventional method, on the casting cavity forming side, seen from the front, and there is a predetermined amount of metal poured from above. A sprue forming recess 22 is formed to form an upwardly opened sprue to receive the molten metal, and a runner is formed following the sprue forming recess 22 to guide the molten metal to be poured. A runner forming recess 24 is provided for forming the runner, and furthermore, casting cavity forming recesses 26 are provided on both sides of the runner forming recess 24 for forming the desired casting product. It is formed in a state connected to the path forming recess 24.

As is well known, such a mold 20 has a sprue forming recess 22 and a runner forming recess 24.
and another mold 20 that cooperates with the casting cavity forming recess 26 to form a predetermined sprue, runner, and casting cavity, as shown in FIG. , a sprue, a runner, and a casting cavity are placed on their mating surfaces.
Each will be formed. Also,
By this superposition, the mating surface (parting line) 2
8 is formed in a substantially vertical direction. Note that the sprues, runners, and casting cavities are usually formed on both sides of the mold 20, as shown in FIG. 1C.

In addition, in such a mold structure, the lower part of the runner forming recess 24, in other words, the runner forming recess 2
Both casting cavity forming recesses 26, 26 in 4
A shell accommodating recess 30 having a substantially semicircular cross section is formed in each mold 20 near the top of the branching point in the direction. A bottomed cylindrical shell 36 containing a predetermined ceramic porous body 32 and having a molten metal passage hole 34 at the bottom is fitted into the shell accommodating recess 30 to form a molten metal passage as shown in FIG. It has come to be possible to set the rules by dividing the

By the way, the ceramic porous body 32 accommodated in such a shell 36 is as shown in FIG.
It consists of a three-dimensional network skeleton structure with continuous pores, such as cordierite, alumina,
Alternatively, it is a ceramic foam composed mainly of SiC, etc., with a high porosity (for example, about 80 to 90%) and continuous pores like a sponge, and has a jagged shape on its entire surface. It is something. This ceramic porous body 32
In addition to the disk-like or cylindrical shape shown in the drawings, various shapes such as rectangular (rectangular parallelepiped) and polygonal shapes are used.

In addition, since the shell 36 that accommodates the ceramic porous body 32 is in contact with the molten metal that is being poured, it should be made of a material that has excellent fire resistance and does not adversely affect the quality of the molten metal. A material with a smooth surface, such as a shell molded product or a ceramic product, is preferably used. As shown in FIGS. 4 and 5, this shell 36 has a bottomed cylindrical shape with a substantially hexagonal planar outline, and at least the ceramic porous body 32 accommodated therein. The ceramic porous body 32 is formed at a height such that it covers the side surface, and has an inner surface shape that minimizes the gap between the porous ceramic body 32 and the side surface of the ceramic porous body 32 to be accommodated. A molten metal passage hole 34 of a predetermined size is formed in order to guide the molten metal passed through to the casting cavity side in the mold. Further, on the outer circumferential surface of the shell 36, a claw portion 38 having a rectangular cross section and serving as a flange-like protrusion is provided at an upper end thereof and protruding laterally.

As described above, the shell 36 containing such a porous ceramic body 32 is placed between the molds 20 and 20 so as to partition the molten metal passage (gate or runner) formed by overlapping the molds 20, 20.
It is fitted into the shell housing recess 30 of No. 0 and set. Therefore, in this setting operation, since the ceramic porous body 32 does not come into direct contact with the mold 20 (more specifically, the shell accommodation recess 30), the The problem that the foundry sand is scraped off the jagged surface of the ceramic porous body 32 does not occur at all.

Further, as described above, the shell 36 in this embodiment has a flange-like claw portion 38 on its outer peripheral surface, and as shown in FIG. 3, when it is set in the mold 20, The claw portion 38 is fitted into the accommodating portion 30 in such a state that it protrudes into the mold 20, thereby effectively preventing the shell 36 from falling out of the set mold 20, and Since the shell 36 can be well held in a predetermined position by the action of the claw portion 38 and the tilting of the shell 36 can be effectively prevented, when the molds 20 are stacked, Scraping off of the molding sand by the shell 36 can be effectively prevented.

By the way, in this embodiment, the core setter (core loading device) used in the conventional vertical casting method can be suitably used for the setting work of the shell. can be done more quickly and efficiently.

That is, as shown in FIGS. 3 and 6, the resin layer 4 covering the front surface of the core setter 40
A fitting part 44 having a shape corresponding to the shell 36 is provided at a predetermined position of No. 2, and at a rotating position of the core setter 40 as shown in FIG.
The shell 36 is fitted into the fitting portion 44 and held by the suction force of air applied through the resin layer 42. And the core setter 40
After rotating around the axis of the rotation shaft 46,
As shown in FIGS. 3 and 7, the shell 36 is fitted into the shell receiving recess 30 formed in the mold 20 by moving relatively close to and abutting against the mold 20. Then, the air suction force of the core setter 40 is released and the core setter 40 is held in the recess 30. By repeating such operations and sequentially overlapping the molds 20 in the horizontal direction as shown in FIG. 7, a shell 36 that accommodates the ceramic porous body 32 is disposed within the runner. This results in the formation of a cast cavity.

Note that, as described above, the shell 36 in this embodiment has the flange-like claw portion 38 on its outer peripheral surface, so that when it is set in the mold 20, it has directionality, in other words, it It is necessary to fit the claw part 38 into the claw part accommodation recess of the housing part 30, but this shell 36 has a substantially hexagonal planar outline as shown in FIG. As shown in FIG. 6, the core setter 40 is fitted into the fitting portion 44 in a directional manner, and the mold 20 is fitted into the shell accommodation recess 30. Settings can be made easily and accurately.

Furthermore, as shown in FIG. 5, the shell 36 in this embodiment is centered on a portion located on the mating surface 28 of the mold 20 on the upper and lower surfaces of the main body 36 and the upper and lower surfaces of the claw portion 38. In other words, the upper and lower surfaces of each shell 36 are inclined surfaces that approach each other as they move away from the center plane (the mating surface 28). Fitting into core setter 40 and mold 20
This makes it easier and more convenient to set up. The angle of inclination of each surface with respect to the horizontal plane (α in Fig. 5) is set appropriately depending on the shape and size of the shell, but usually the angle of inclination is about 1° to 5°. It will be formed by

Therefore, by using the core setter 40, the mold 2 of the shell 36 can be
The setting to 0 can be performed accurately and with good workability, and thereby the scraping of molding sand when setting the shell 36 can be more effectively prevented.

In this way, the shell 36 containing the predetermined ceramic porous body 32 is placed in the mold 2.
When a predetermined casting operation is performed in a state where the molten metal passage formed between 0 and 20 is partitioned and set, the molten metal poured from above flows from the sprue 22 into the molds 20 and 20. It will be guided inside and flow down the runner 24,
A ceramic porous body 32 supported by a shell 36 is disposed therein, and the molten metal is passed through the porous ceramic body 32, passes through the molten metal passage hole 34 at the bottom of the shell 36, and then passes through the runner. 24 and into the respective casting cavities 26, metal oxides and non-metallic inclusions such as slag and foundry sand mixed in during the molten metal pouring operation are removed from the ceramic porous body 3.
The molten metal is effectively filtered by the filter effect of No. 2, and the cleaned molten metal is introduced into the casting cavity 26. Therefore, even if you do not pay close attention to the pouring process of molten metal, the quality of the resulting cast products is significantly improved, and problems such as reduced product yield due to sand encroachment can be effectively solved. This can be suppressed by

Moreover, in the present invention, since the loading operation of the ceramic porous body 32 into the mold 20 is performed via the shell 36,
It is possible to effectively prevent dust from falling off the mold 20 due to contact with the jagged surface of the ceramic porous body 32, and furthermore, when the shell 36 is loaded into the mold 20, the dust inside the shell housing recess 30 can be effectively prevented. The shell 36 can be held well by the action of the claws 38, and the shell 36 can be effectively prevented from tilting. Scraping can also be effectively prevented, and as a result, the ceramic porous body 32
This makes the loading operation extremely easy, and also effectively eliminates the reduction in product quality or yield caused by the entrainment of dropped foundry sand into the molten metal.

Furthermore, in the present invention, since the porous ceramic body 32 is loaded into the mold 20 while being housed in the shell 36, the porous ceramic body 32 is held in the runner 24 substantially in the same manner as the shell 36. This is done by the shell 36, and therefore the size of the expensive ceramic porous body 32 can be set to the minimum necessary for the amount of molten metal passing through, which is economical. It also has the advantage of being superior.

The embodiments according to the present invention have been described in detail above, but the present invention can be realized by the description of such embodiments.
This should not be construed in any restrictive manner.
It goes without saying.

For example, in the method according to the present invention, an inoculant or a graphite spheroidizing agent is placed on the ceramic porous body 32 set in the molten metal passage formed between the molds 20, 20 in the above embodiment. This makes it possible to improve the molten metal (molten cast iron) that is poured into the mold. That is, according to the present invention, when manufacturing a desired cast product according to the vertical casting method, it is also possible to perform instant inoculation or instant spheroidization treatment within the mold. If such a method is followed, the poured molten metal will pass through the porous ceramic body while inoculating the inoculant, and will be introduced into the casting cavity in an over-inoculated state and solidified. This makes it possible to produce cast products that are sound on both the inside and outside while fully demonstrating the effect of normal in-mold inoculation.For example, (a) the amount added is about 1/3 compared to ladle inoculation. Demonstrates the additive effect in
(b) It exhibits characteristics such as no loss of inoculation effect over time.

In addition, the shell 3 used in the above embodiment
The claw portion 38, which is formed to protrude laterally on the outer circumferential surface of the shell 36, has a substantially rectangular cross section at the upper end in the axial direction of the shell 36, but its formation position is limited. Not a thing,
In addition, even if it has such a shape, it is sufficient that the shape is protruding so that it can be inserted into the mold 20 to be fitted. You can leave it there.

Further, the planar outer shape of the shell 36 is approximately hexagonal, but this is to facilitate fitting of the shell 36 into the core setter 40 in a predetermined direction.
In addition, there are various ways in which the shell 36 can be fitted into the core setter 40 in a directional manner, such as by providing a protrusion or fitting a protrusion on the core setter 40 side into a recess on the side surface of the shell 36. It is possible to form it in any shape or structure, and even when it is formed in a shape without directionality such as a cylindrical shape, the effects of the present invention as described above can be fully achieved. It's something you get. However, since the directionality of the shell 36 is such that the claw portion 38 of the shell 36 is accurately fitted into a predetermined position in the shell accommodation recess 30 of the mold 20, for example, the orientation of the shell 36 is
Of course, when the hole is formed in the shape of a hat having a through hole at the bottom as described above, its directionality does not matter.

Furthermore, the shell 36 used in the above embodiment has a slope at a predetermined angle in the opening surface, the bottom surface, and the claw portion in a direction that approaches each other as the distance from the center increases.
As a result, fitting into the mold 20 can be done easily and satisfactorily; however,
When carrying out the present invention, for the shell,
It is not necessary to set such a gradient.

In addition, in the present invention, the position of such a shell within the molten metal passage is not limited. However, compared to arranging such a shell in the molten metal passage near the sprue, in the case where it is arranged near the branching point of the molten metal passage as in the above embodiment, the casting process starts from the position where the shell 36 is disposed. The distance of the runner leading to the cavity is shortened, thereby making it possible to more effectively prevent molding sand from being scraped off by the molten metal from entering the casting cavity, and the molten metal head becomes higher. This brings about advantages such as shortening the pouring time and further improving productivity.

(Effects of the Invention) As is clear from the above description, the present invention provides a ceramic porous body having a cylindrical shape with a bottom and a flange-like protrusion projecting laterally. When the molten metal is housed in the shell, it is set in the molten metal passage formed between the molds, and by cleaning the molten metal poured into the mold, Reduces the need for careful demolition work,
It also prevents foreign matter such as slag and sand from getting mixed in, allows unskilled workers to perform pouring work, and simplifies automatic pouring equipment. It is possible to prevent the shell from falling off after being set in one of the molds, thereby facilitating the work of setting the ceramic porous body and automating the work, and at the same time, at the time of setting or overlapping the molds. This has completely solved the problem of scraping off the foundry sand.
This is where the great industrial significance of the present invention lies.

[Brief explanation of drawings]

Figures 1a, b and c are cross-sectional explanatory views showing each step of the vertical casting method, respectively, and Figure 2 shows the cavity forming side of one of the molds used in an embodiment of the present invention. FIG. 3 is a cross-sectional explanatory view showing a state in which such molds are stacked, and FIG. 4 is a ceramic porous body used in the embodiment shown in FIG. FIG. 5 is a longitudinal cross-sectional view of the shell, FIG. 6 is a partial cross-sectional view showing the shell fitted into the core setter, and FIG. 7 is a perspective view of the core setter. It is a perspective explanatory view for explaining an operating state. 20: Mold, 22: Gate forming recess, 24:
Runway forming recess, 26: Casting cavity accommodation recess,
28: mating surface, 30: shell forming recess, 32:
Ceramic porous body, 34: Molten metal through hole, 36: Shell, 38: Claw portion.

Claims (1)

[Claims] 1. Vertical molds are stacked horizontally,
A predetermined casting cavity is formed between these molds, and molten metal poured from above is guided into the casting cavity to form the desired cast product. A porous ceramic body is housed in a bottomed cylinder that covers at least its side surfaces, has a molten metal passage hole at the bottom, and is provided with a flange-like protrusion projecting laterally, and a molten metal passage is formed on the mating surface of the mold. A bottomed cylindrical body containing the ceramic porous body is set and held in the passage forming part of one of the molds forming the cylindrical body in the cylindrical body portion including the protrusion, and then the other mold is placed on top of the other mold, The predetermined casting cavity and molten metal passage are formed between these molds, and the molten metal passage is partitioned off by a ceramic porous body housed in the bottomed cylinder. A vertical casting method characterized in that the molten metal is guided into the casting cavity through the ceramic porous body. 2. A patent in which the bottomed cylindrical body housing the ceramic porous body has at least a slope at a predetermined angle on its opening surface and bottom surface in a direction from the center toward the tip of the protrusion toward each other. A vertical casting method according to claim 1. 3. The method according to claim 1 or 2, wherein the bottomed cylindrical body housing the ceramic porous body has a structure that provides a rectangular cross-sectional external shape on a side surface opposite to the protrusion. Vertical casting method.