JP2004298950A - Strainer for removing foreign matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a strainer which has high rigidity, has difficulty in deformation, is easy to manufacture and is high in the removability of foreign matters. <P>SOLUTION: This strainer for removing the foreign matters, which can separate or segment the foreign matters in molten material, is configured of a metallic thin plate having many opened holes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strainer for separating, separating and removing foreign matters in a molten metal to improve casting quality.
[0002]
2. Description of the Related Art Casting is a method in which a molten metal in which a metal is melted is filled in a mold, cooled and solidified to obtain a cast product having a desired shape, and a product having a complicated shape can be formed in one step. For this reason, it is widely used as a molding means for various industrial products such as parts for vehicles. In the case of casting, the inclusion of foreign matter (oxide film, etc.) in the molten metal causes internal defects and appearance defects, which lowers the mechanical strength and yield of the cast product. Therefore, it is important to increase the cleanliness of the molten metal. is there. Degassing treatment, deoxidation treatment, filtration treatment and the like are known as means for cleaning molten metal.
[0003] As a preferable means for purifying the molten metal, a method is used in which a strainer is attached to a gate of a mold at the final stage of the casting process. Foreign substances such as oxide films can be generated not only due to the metal raw material itself and its melting process, but also during the casting process. Therefore, even if the above-described cleaning means such as degassing is performed, foreign substances generated thereafter are removed. Can not. The strainer attached to the gate is useful in that foreign substances in the molten metal can be physically, mechanically separated, separated, and removed immediately before the molten metal is filled into the mold cavity.
However, since the conventional strainer is formed by processing a metal net formed by knitting a metal wire into a mesh shape into a predetermined shape, the strainer is inferior in rigidity and easily deformed, and a gap between the strainer and, for example, a sprue in a sprue system. As a result, there has been a problem that foreign matter is mixed into the molten metal filled in the cavity of the mold.
[0005] It seems that no proposal has hitherto been made for such a problem. Patent Document 1 is disclosed as a proposal for improving a filter used for a gate.
A method of fixing the strainer to, for example, a sprue by means of fitting, bonding or the like to prevent the generation of a gap is also conceivable. However, since the strainer is filled every casting, fixing the strainer complicates the work and increases the production efficiency. It is not preferable because it causes a decrease in temperature and a trouble such as a decrease in mold temperature.
In order to increase the rigidity, a method of manufacturing a strainer by processing a thicker metal wire or a metal wire having a higher rigidity may be considered. It is difficult to manufacture using a machine that is generally distributed. Therefore, it is difficult to adopt as a consumable item in consideration of cost and delivery time.
[0008]
[Patent Document 1]
JP-A-6-2699898
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide high rigidity, non-deformability, easy manufacture, and low foreign matter removal capability. It is to provide a high strainer. As a result of repeated studies, it was understood that in the conventional improvement of the wire mesh structure in which the metal wire was knitted, there was a problem that the wire mesh was custom-made, and the design flexibility was poor. On the other hand, it was considered that the conventional screen separating mechanism using a mesh has a simpler structure and a higher removal effect than other mechanisms. Therefore, as a result of researches for realizing almost the same form by taking a completely different approach, it was found that the above object can be achieved by the following means.
[0010]
That is, according to the present invention, there is provided a strainer for separating or separating foreign matter in a molten metal, the strainer comprising a thin metal plate having a large number of holes. Is provided. In the present invention, the holes are preferably arranged in a staggered manner. The holes may have the same or different center distances in the long and short directions.
Further, according to the present invention, there is provided a mold used for casting of a cast product and provided with a plurality of gates for filling a cavity with a molten metal, wherein the foreign material removing strainer is mounted on the gate. Is done. In addition, the strainer for removing foreign matter according to the present invention can be suitably used for a multi-gate mold, and the multi-gate mold equipped with the strainer for removing foreign matter according to the present invention improves the casting quality by utilizing the features of the multi-gate. However, the foreign matter removing strainer according to the present invention is not limited to a multi-gate mold, but can be used for a center gate low-pressure casting mold and other molds.
Further, according to the present invention, there is provided a filter for separating or separating foreign matter in a molten metal, the filter comprising a thin metal plate having a large number of holes. .
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described mainly with respect to a foreign matter removing strainer, but the present invention should not be construed as being limited to the following description, and the scope of the present invention is not limited to the following description. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the present invention.
The strainer for removing foreign matter according to the present invention is a strainer for treating a molten metal as a molten metal and separating or separating foreign matter in the molten metal. The foreign matter removing strainer of the present invention is characterized in that it is formed of a metal sheet having a large number of holes.
Since the basic structure is different from the conventional wire mesh in which a plurality of metal wires are knitted, a large number of holes are formed in an integrated thin metal plate, so that it has high rigidity and is bent or distorted by the passage of the molten metal. Nothing. Therefore, for example, when installed at the gate of the mold, without deformation during the passage of the molten metal to create a gap between the gate and the strainer, in the final stage of the casting process to reliably separate foreign matter in the molten metal, It can be separated and removed to improve casting quality. Further, in this case, since it is not necessary to fix the strainer to the gate of the mold, the loading operation for each casting is easy, the production efficiency does not decrease, and troubles such as a decrease in the mold temperature do not occur.
In the present specification, the metal sheet refers to a metal sheet or sheet, and the thickness is not limited, but a sheet having a thickness of about 0.2 to 0.5 mm is often used. . These are generally distributed in the market and there are many types. The means for forming a large number of holes in a thin metal plate is not limited, and a punching method, an expanding method (a method of making a cut and expanding it), and the like can be employed. Can be carried out by using a generally available machine. That is, the foreign matter removing strainer of the present invention can be obtained by subjecting a generally distributed workpiece to processing by generally used processing means. Of course, since it is a thin metal plate, a means for processing into a predetermined strainer shape after or before drilling a large number of holes can employ a commonly-used bending process, cutting process, etc., and the process is easy.
Further, since the strainer for removing foreign matter according to the present invention has flexibility in design, it can be obtained by using a generally available processing means using a workpiece to which a variety of types are circulated. For example, it is easy to change the material and thickness of the thin metal plate. Further, the ratio of the area of the metal sheet to the area of the hole (opening) (referred to as an aperture ratio) can be easily changed by changing the number and size of the holes to be formed in the metal sheet.
By making these design changes, the location of the strainer, the condition of the molten metal to be processed (whether it is assumed that there are many foreign substances or whether it has been cleaned to some extent), etc. Thus, a strainer having optimum rigidity, aperture ratio, material and the like can be obtained.
This design flexibility is also an effect that could not be realized with a conventional wire mesh structure strainer. In the case of a wire mesh structure, a machine for knitting a metal wire is not generally distributed and is a special machine. Since a metal wire to be knitted is limited, the range of rigidity and material selection becomes extremely narrow. In addition, the method of knitting is also limited, and it is difficult to change the thickness and mesh density of the metal wire, and the changeable range of the ratio of the area occupied by the metal wire to the mesh (opening) area (corresponding to the opening ratio) is extremely narrow. This is not the case with the present invention.
In the strainer for removing foreign matter according to the present invention, the object to be treated is a molten metal. If the molten metal is a molten metal that may contain foreign matter and is finally solidified, it is used as a raw material for casting. It is not limited to those used.
The foreign matter contained in the molten metal refers to one that causes a decrease in mechanical strength or a decrease in yield, irrespective of metal or nonmetal. Specifically, in the case of a molten metal used for casting, for example, an oxide (dross) such as an oxide film, a slag (slurry), an unintended intermetallic compound, and the like are exemplified.
As described above, the metal sheet refers to a metal sheet or sheet. The thickness is not limited as long as a certain rigidity can be maintained, and may be determined depending on the purpose of using the strainer, the state of the molten metal to be processed, the installation location, and the like. Specifically, for example, when the object to be processed is a molten metal used for casting, it is usually preferable that the thickness is not large in terms of its function, and it is on the order of several μm to several mm. The material of the metal sheet is not limited as long as the melting point is higher than the temperature of the molten metal and the material has a certain rigidity. Specifically, iron, titanium, nickel, aluminum, copper, or alloys thereof including various stainless steels can be used.
In the strainer for removing foreign substances according to the present invention, the shape, size, density, etc. of the holes formed in the metal sheet are not limited. These may be determined depending on the purpose of the strainer, the state of the molten metal to be processed, the installation location, and the like. Although holes having different shapes and sizes may be mixed, a mode in which generally the same holes are arranged at a constant pitch is preferable in order to normally exert a function as a strainer.
FIGS. 1 (a) to 1 (c) are top views of metal sheets with holes. FIG. 1A shows a substantially rectangular metal thin plate 24 having a large number of substantially circular holes 21 formed therein. FIG. 1B shows a substantially rectangular metal thin plate 24 in which a large number of substantially rectangular holes 22 are opened. FIG. 1C shows a substantially circular metal thin plate 20 in which a large number of generally rhombic holes 23 are opened. These can be processed by a punching method.
In the embodiment shown in FIG. 1 (c), as shown in FIG. 1 (d) in which the hole is enlarged, the center distance L in the long direction and the center distance S in the short direction are different from each other. Are arranged in a zigzag pattern. This embodiment is easy to produce by expanding. In the present invention, the center distance L in the long direction and the center distance S in the short direction may be the same. Regarding the shape and size of the hole, specifically, for example, when a molten metal used for casting is to be processed, when the hole 23 having the shape shown in FIG. The center distance L can be about 50 μm to 3 mm, and the center distance S in the shorter direction can be about 50 μm to 3 mm.
In the foreign matter removing strainer according to the present invention, the shape of the strainer is not limited, and is determined by the purpose of use, installation location, and the like. For example, it can be in the form of a hat, which is the form of a normal strainer, a bowl with a flat or curved bottom, or an inverted cone.
Next, the multi-gate mold according to the present invention will be described by way of an example, and in that example, the shape and installation method of the foreign matter removing strainer according to the present invention will be described. The multi-gate mold according to the present invention is a mold in which the foreign matter removing strainer according to the present invention is mounted on a gate. The multi-gate mold refers to a mold that is used for casting of a casting product and has a plurality of gates for filling a cavity with a molten metal. In the multi-gate mold, since the molten metal is poured into the mold from a plurality of gates, the flow distance of the molten metal in the mold is short, and the temperature of the molten metal is small, so the flow of the molten metal in the mold is small. It is a mold having the advantage that it has good casting defects and can handle thin products. A multi-gate mold in which a strainer is provided at each gate is capable of separating, separating, and removing foreign matters in the molten metal immediately before filling into the cavity, and thus is useful for improving the yield of casting products.
In a conventional strainer, for example, when it is installed at a gate, as a result of forming a gap between the gate and the strainer, foreign matter may be mixed into the molten metal filled in the cavity of the mold. As a result, the features of the multi-gate mold could not be fully utilized. According to the multi-gate mold provided by the present invention, it is possible to obtain a thinner cast product at a high yield without such a problem.
FIG. 3 is a perspective view showing a vehicle wheel, which is an example of a casting product, with the design surface facing downward in the figure. FIG. 2 is an embodiment of a multi-gate mold according to the present invention. FIG. 4 is a sectional view of a mold for casting and molding the vehicle wheel 41 shown in FIG. 3. The vehicle wheel 41 includes a cylindrical rim as a thin portion and a spoke 44 as a thick portion connecting the rim. The rim includes an outer rim 43 on the spoke 44 side and an inner rim on an opposite end. It consists of a rim 42. In order to reduce the thickness of the rim, which is a thin portion, and secure the strength, it is necessary to perform good casting with no defects, and foreign matter is not allowed to enter the cavity.
The multi-gate mold 11 shown in FIG. 2 is a mold used for a low-pressure casting method, and comprises an upper mold 1 forming a cavity 4 which is a molding space, a horizontal mold 2 and a lower mold 3. It is connected to a stalk 5 which is a flow path when the molten metal is pushed up from a holding furnace (not shown) to a mold (cavity 4). The multi-gate mold 11 includes a plurality of gate systems including an intermediate stalk 17 and a weir 19 for supplying molten metal to the cavity 4, and a strainer 18 is provided at a gate located between the intermediate stalk 17 and the weir 19 in each gating system. is set up.
In general, the molten metal is cleaned in the process of reaching the holding furnace, but even so, the molten metal that has not been filled in the cavity 4 in the low-pressure casting method repeats returning to the holding furnace. It is not always possible to completely prevent the generation of foreign substances such as slag in the molten metal and the formation of an oxide film on the walls of the stalk in the lower mold 3 and the lower mold 3. In the multi-gate mold 11, the strainer 18 that is hardly deformed and does not generate a gap is provided immediately before the cavity 4 that is a molded body space. The mechanical strength of the wheel 41 and the reduction in yield can be prevented.
FIG. 4 is a perspective view of the strainer 18. The strainer 18 is manufactured by adopting the thin metal plate 20 having the hole 23 shown in FIG. 1C, and has a substantially hat-like shape including a flange portion 48 and a cylindrical portion 47 as shown. Present. The material constituting the metal thin plate 20 is SS, and its thickness is 500 μm. The center distance L in the long direction of the hole 23 is 500 μm, and the center distance S in the short direction is 250 μm.
Hereinafter, an embodiment of a method for manufacturing a foreign matter removing strainer according to the present invention will be described with reference to an example of manufacturing the strainer 18 shown in FIG. First, a thin metal plate made of SS and having a thickness of 500 μm is prepared. It is available as a roll of constant width.
Next, the rolled metal sheet is expanded to form holes. Specifically, for example, a number of cuts of 500 μm perpendicular to the longitudinal direction are formed in a zigzag pattern on the thin metal sheet of the wound body, and the cuts are spread and spread in the longitudinal direction. After a hole having a distance of 250 μm is formed and rolled, it is washed.
Next, the rolled metal sheet having a hole is cut, and a hole 23 shown in FIG. 1 (c) is opened, and a substantially circular metal sheet 20 having a predetermined size is formed. obtain. Then, the flange portion 48 and the cylindrical portion 47 are formed by press working and bending, and the strainer 18 is obtained.
As described above, the foreign matter removing strainer according to the present invention, the manufacturing method thereof, and the multi-gate mold have been described. The features of the foreign matter removing strainer according to the present invention, which are formed of a thin metal plate having a large number of holes, are as follows. It has almost the same function of separating, separating, and removing foreign substances such as slag, and has almost the same function, and can be applied as a filter including a screen, a filter, or the like, which is used in a different place, used, or used. The foreign matter removing filter according to the present invention refers to these, and has substantially the same purpose and substantially the same function as described above, and the operation and effect are substantially similar to the foreign matter removing strainer according to the present invention. Since there is, do not repeat. In general, for example, in a casting process, a screen refers to a filter placed in the middle of a runner, and a filter is installed together with or incorporated with a degassing device or the like, or a filter that removes foreign substances more actively. Refers to what is installed as a vessel.
[0037]
According to the present invention, there is provided a strainer which has high rigidity, has difficulty in deforming, is easy to manufacture, and has a high foreign matter removing ability. This strainer, for example, when installed in the mold gate, does not cause a gap between the gate and the strainer even after long-term use, and is used for filling the molten metal filled in the mold cavity in the final stage. It prevents foreign substances from being mixed and does not cause a decrease in mechanical strength and yield of the cast product.
[Brief description of the drawings]
FIGS. 1 (a) to 1 (d) are top views showing an embodiment of a thin metal plate having holes formed therein, which constitutes a foreign matter removing strainer according to the present invention, and FIG. FIG. 1 (b) shows a generally rectangular metal sheet having a large number of substantially rectangular holes, and FIG. 1 (c) shows a substantially rectangular metal sheet having a large number of substantially rectangular holes. FIG. 1 (d) is an enlarged view of the holes of the metal sheet shown in FIG. 1 (c), showing a substantially circular metal sheet having many holes.
FIG. 2 is a cross-sectional view illustrating an embodiment of a multi-gate mold according to the present invention.
FIG. 3 is a perspective view showing an example of a casting product.
FIG. 4 is a perspective view showing an embodiment of a foreign matter removing strainer according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Upper mold, 2 ... Horizontal mold, 3 ... Lower mold, 4 ... Cavity, 5 ... Stoke, 11 ... Multi-gate mold, 17 ... Intermediate stalk, 18 ... Strainer, 19 ... Weir, 20, 24 ... Metal thin plate, 21 , 22, 23 ... hole, 41 ... vehicle wheel, 42 ... inner rim, 43 ... outer rim, 44 ... spoke, 47 ... cylinder part, 48 ... flange part.

Claims (4)

What is claimed is: 1. A strainer for separating or separating foreign matter in a molten metal, comprising a thin metal plate having a large number of holes. 2. The foreign matter removing strainer according to claim 1, wherein the holes are arranged in a staggered manner. 3. A multi-gate mold having a plurality of gates used for casting of a casting product and for filling a cavity with a molten metal, wherein the foreign matter removing strainer according to claim 1 or 2 is mounted on the gate. What is claimed is: 1. A filter for separating or separating foreign matter in a molten metal, comprising a thin metal plate having a large number of holes.

Images