JP2007111741A - Casting method for enabling highly efficient production - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a casting method where, in a gas permeable mold composed of a plurality of product part cavities, molten metal can be filled into required cavity parts such as product parts or product parts and gate-riser parts, a pouring yield is remarkably increased and production efficiency is improved, and further, post-stages such as releasing of a flask and a product separation can be remarkably simplified. <P>SOLUTION: To a mold where the upper part is provided with a pouring basin, and further, a plurality of sprue holes communicating from the bottom face of the pouring basin to the product part cavities and/or gate-riser part cavities are provided, a prescribed amount of molten metal is poured into the pouring basin, and, through the plurality of sprue holes, the required cavity parts among the mold cavities are filled with molten metal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a casting method in which molten metal is poured into a breathable mold from above the mold.

  As the air-permeable mold, a mold formed using sand particles is most common, but a mold formed using ceramic particles or metal particles is also widely used. Further, even a mold that is hardly breathable, such as plaster, can be regarded as a breathable mold if mixed with a breathable material or partially used to impart breathability. Further, even in the case of a mold that does not have air permeability at all, a mold provided with air permeability by providing a vent hole or a vent hole can be regarded as a gas permeable mold. The breathable mold in the present invention includes these breathable molds described above. In the following description, the case of using the most common sand mold will be described.

  In general, in casting, the basic structure of the mold cavity is composed of a gate cavity, a runner cavity, a feeder cavity, and a product cavity. Hereinafter, each cavity portion is referred to as a gate portion, a runner portion, a feeder portion, and a product portion. The gate is a shape that communicates vertically from the upper part of the mold to the parting surface (upper and lower mold dividing surfaces) of the mold. Further, the runner portion is arranged on the parting surface, and acts to distribute and fill the molten metal from the gate into each product portion or hot water portion. In addition, if necessary, a skein part or a vent hole for discharging unnecessary molten metal from the product part may be provided. Suppose that it is comprised from a part, a feeder part, and a product part.

  In any casting method, the pouring is completed by filling all these cavities. After the solidification is completed, only the necessary product parts are separated and taken out from these cavity parts, and finished to obtain the final casting product.

  That is, the sprue part, runner part, and hot water part excluding the product part are finally separated from the product part as unnecessary parts, and again used as a return material for remelting. Of these unnecessary parts, the feeder part is necessary to compensate for the soundness of the product part during the solidification process, but the runner part and the sprue part are necessary only for filling the cavity during pouring. Is something.

  Also, in cast iron castings etc., graphite crystallizes during the solidification process and volume expansion occurs, so it compensates for part of the shrinkage of the molten metal. ing. In this case, there is no need for a feeder part, and only the product part needs to be filled with molten metal.

  As described above, in the casting method of the prior art, in order to obtain the originally intended product, a pouring process in which the molten metal is finally filled in unnecessary sprue portions, runners and feeders is also performed. I'm taking it. The problems are as follows: (1) The injection yield expressed as product part weight / total injection weight is low. Therefore, production efficiency is low and energy cost is high. In addition, as described above, (2) a great amount of man-hours are required for separating and removing unnecessary portions at the time of releasing the frame. Etc.

  This is extremely irrational. On the other hand, if the required cavities of the mold cavities can be filled and solidified by some method, the injection yield will be greatly improved, and post-processes such as unpacking and product separation will occur. Can be greatly simplified.

  In the case of a mold made up of a plurality of product parts, the hot water is poured from one large pouring part, and the molten metal is filled into the plurality of hot water supply parts and product parts while branching the runner part. However, since the branched runners are not necessarily symmetrical, (3) it is difficult to evenly distribute and fill the molten metal into each product part during the pouring process. (4) The filling time of the molten metal into each product part is longer than when the mold is composed of one product part. For this reason, casting defects such as hot water boundaries and non-rotations are likely to occur. In addition, as countermeasures, (5) since hot pouring is performed, defects such as shrinkage and seizure are likely to occur. There are problems such as.

  In addition, (6) a machine-shaped line usually uses a side hot-water feeder that is not open at the top, so that it is difficult to supply hot water from the hot water to an isolated thick-walled portion. (7) Since the product is naturally cooled in the mold after pouring, the solidification rate is slow, so that defects are likely to occur and the material strength is not improved. There are problems such as.

As described above, the casting method in which the molten metal is poured from the upper part of the air-permeable mold has various problems as described in (1) to (7). Among these, (1) and (2) are particularly serious problems in terms of production efficiency and energy cost. This is an important issue related to the amount of CO ₂ that is ultimately the cause of global warming, given that energy consumption is extremely high in casting production.

  Therefore, the prior art has been investigated. In the casting method in which the molten metal is poured from the upper part of the mold of the air-permeable mold, the necessary cavity portion of the mold cavity is filled with the molten metal, and the above (1) to (7). It has not been possible to find a casting method that can solve such problems.

  Therefore, Patent Documents 1 and 2 are listed below as reference examples of the prior art. However, all of them fill the molten metal into all the cavity portions of the sprue portion, the runner portion, the feeder portion and the product portion, and do not solve the above problems.

  Patent Document 1 (Japanese Patent No. 48-21689) states that “an upper mold, a lower mold, at least one sump disposed on the top of the upper mold, a plurality of sprues, and the sump are described above. A groove portion that communicates with a plurality of gates, and the dimension of the previous groove portion is a difference in the amount of molten metal between the supply from the casting ladle and the outflow from the gate during casting. The groove portion has a depth greater than the minimum depth necessary to absorb the difference and to prevent overflow during casting, but is lowered below the highest position of the mold product space. There is disclosed a mold that is positioned at least immediately near the highest position, and the bottom portion of the groove portion is inclined downward toward the gate.

  The object of Patent Document 1 is to pour the upper mold puddle, the groove portion and the plurality of gates, and the pouring using the runner on the mold dividing surface, with the bottom of the groove portion being at a minimum higher than the highest position of the mold product space The mold is positioned and inclined, and an appropriate amount of molten metal is poured.After the pouring is completed, the molten metal is not filled in the puddle and groove, and only the pouring gate, runner, product, and hot water are filled with molten metal. It is intended to be filled. This significantly improves the injection yield.

  However, in this case, the path for the molten metal to fill the mold cavity is in the order of the puddle, the groove, the sprue, the runner, the hot water, and the product, and the molten metal is filled into the product through the runner and the hot water. Is the same as the casting method of the prior art. Also, it is not intended at all to cast a product without a feeder. Moreover, one hot water pool is used for one product, and it is complicated when applied to a mold of a plurality of product cavities. Therefore, the above problem is not solved.

  In Patent Document 2 (Patent No. 2715682), “a concave shape where molten metal accumulates is formed, and at the bottom of the concave shape, the upper end openings of at least two down sprues are located between the openings, and There is disclosed a mold gate shape that includes a mountain-shaped raised portion that partitions a bottom portion and has a super portion with a height up to the middle of the depth of the concave shape.

  The purpose of Patent Document 2 is to fill molten metal into a plurality of hot water and products by using a concave hot water pool, a plurality of down sprues (pouring gates), and a branch-shaped runway formed along the mating surface. In addition, the two down sprues are divided by a mountain-shaped swell provided with a water sump between the two down sprues.

  However, in this case as well, the path for the molten metal to fill the mold cavity is in the order of the puddle, down sprue, runner, feeder, and product, and the molten metal is filled into the product through the runner and feeder. This is the same as the conventional casting method. Nor is it intended to reduce the volume of the down sprue that is filled or to cast the product without a feeder. Therefore, the above problem is not solved.

  What is disclosed in the above patent documents is “a mold or a mold shape of a mold” and is not a casting method, but can be said to be one suggestion of a method for solving the above problems. However, even if the prior art disclosed in these is regarded as a casting method, the injection yield is still not sufficient, and the subsequent processes such as unpacking and product separation are complicated. Further, it does not solve the problems such as inability to perform uniform distribution and filling of the molten metal, long filling time, easy casting defects, difficult to supply hot water from the hot water, and inability to improve the material strength.

Patent 48-21689 Patent No. 2715682

  The present invention is intended to provide a casting method having the following characteristics in view of the above problems of the prior art.

  (1) The molten metal can be filled in a necessary cavity portion of the mold cavity, and the injection yield is greatly improved. (2) Subsequent processes such as unpacking and product separation are greatly simplified. (3) The molten metal can be uniformly distributed and filled in each product part during the pouring process. (4) The filling time of the molten metal into each product part is shortened. (5) Low temperature pouring is possible. (6) Hot water supply to an isolated thick part is easy. (7) After pouring, a rapid solidification rate is obtained. As a result, shrinkage defects are less likely to occur and the material strength is improved.

The effects of solving the above-mentioned problems are as follows: (1) The injection yield is greatly improved, and post-processes such as unpacking and product separation are greatly simplified, so that production efficiency is improved, energy costs are reduced, CO ₂ and other effects can be obtained. (2) The casting quality is improved by improving the pouring process and the effect of the hot water.

(Means 1)
In a casting method in which molten metal is poured from above into a gas permeable mold having a plurality of product cavities, a puddle is provided at the top of the mold and communicated from the bottom of the puddle to the product cavities and / or feeder cavities. A plurality of sprue holes are provided, and a molten metal having a volume substantially equal to a required cavity portion to be filled in the mold cavity is poured into the puddle, and the necessary cavities are passed through the plurality of sprue holes. This is a casting method characterized by filling molten metal into the molten metal.

  First, the structure of the mold will be described using the most common sand mold as an example. A part of the basic structure of the mold cavity of this means is composed of a product part and a feeder part, or only the product part. Usually, in order to prevent shrinkage, a feeder part is required, and it is composed of a product part and a feeder part. However, in some cases, cast iron or the like does not require a feeder part.

  After casting the upper mold and the lower mold, the mold is provided with a hot water reservoir for receiving the poured molten metal on the upper surface of the upper mold. The size of the hot water pool is set to an appropriate size according to the amount of molten metal to be poured. The hot water pool may be molded by molding, or may be molded by cutting after molding.

  Next, a plurality of gate holes are provided to communicate from the bottom of the hot water reservoir to the product portion and / or the hot water supply portion. The gate hole functions as a gate for filling the product part and / or the feeder part with the molten metal received in the hot water pool. Therefore, this means does not use a large gate from one place as in the conventional casting method, and uses a plurality of small gates corresponding to each product part and / or feeder. Moreover, the runner part on the parting surface for distributing and filling the molten metal in each cavity portion as in the prior art casting method is not used.

  It is efficient in terms of the hot-water effect that the pouring hole position is communicated with the hot-water supply portion when there is a hot water. Moreover, it can be made to communicate with a product part. In this case, in consideration of the product shape, a part where the hot water is desired to be effective or a part where the hot water is difficult to rotate is appropriately selected and communicated.

  The size of the sprue hole is determined in consideration of the volume of the product part and the hot metal part filled with the molten metal and the desired filling time. Further, the shape is arbitrary, but a cylindrical one having a circular cross section is easy to mold. The cross-sectional shape may be a uniform cross-section in the longitudinal direction, or a part of the cross-sectional shape can be enlarged to also serve as a feeder. In the case where the feeder is also used, this is referred to as a gate feeder.

  In summary, in this means, the basic structure of the mold cavity is a puddle, a sprue hole, a feeder part, and a product part. In addition, a cavity portion used in the prior art such as a skein portion or a vent hole may be appropriately used as necessary. However, the large sprue part from one place like the prior art and the runner part for distributing and filling the molten metal are not used.

  The casting method will be described with this mold configuration. First, determine the volume of the part you want to fill with molten metal. When there is no feeder part and only the product part, the sum of the product part volume and the volume of the filling part of the gate hole is taken. When there is a product part and a feeder part, the total volume 1 is the sum of the total volume 2 of the filling part of the gate hole. The portion of the sprue hole where the molten metal is filled is determined so as not to hinder the quality of the product in consideration of the shape, size, arrangement, etc. of the product portion and the hot water supply portion. If there is a skein or a vent hole other than the basic cavity part, add the volume of that part as necessary.

  In other words, in order to pursue a high injection yield in this means, after the filling of the molten metal is completed, the molten metal is filled into the minimum required cavity within the range where there is no problem with the quality and function of the product part and / or the feeder part. . Therefore, in this means, the hot water pool is basically not filled with molten metal. However, the amount of the molten metal is slightly too large, or the molten metal is dispersed and left on the bottom surface of the puddle due to the shape or inclination of the bottom surface of the puddle, which is a variation range of this means.

  After the upper mold and the lower mold are matched, a molten metal having a volume substantially equal to the volume of the cavity portion necessary for filling the molten metal is poured into the hot water pool. The molten metal is filled into each cavity through a plurality of gate holes. Here, the approximately equal volume of molten metal means that the mold cavity expands during pouring or the volume of the cavity part that needs to be filled changes as the upper mold rises. I mean. The amount of molten metal to be poured is set to the minimum necessary amount in order to obtain a high injection yield in consideration of the hot water supply effect from the molten metal in the spout hole after completion of the molten metal filling.

  In pouring hot water, it is desirable to provide a filtering member such as a filter in the upper part of the pouring hole in order to prevent inclusions such as inclusions and sand from the pouring hole.

  The molten metal to be filled is a part of the product part and the pouring hole if there is no pouring part, or a part of the product part, the pouring part and the pouring hole if there is a product part and the pouring part. Basically, molten metal is not filled. It should be noted that all the gate holes may be filled to ensure the quality of the product part. Further, there is no large sprue portion and a runner portion for distributing and filling molten metal as in the prior art casting method. The upper part of the product part and / or the feeder part is filled with molten metal in a part of the sprue hole. This portion is removed by folding with a hammer or cut with a saw or the like. In the case of a normal sprue hole, it can be easily folded with a hammer.

  As a result, the necessary cavity portion of the mold cavity is filled with molten metal, and there is no large sprue portion and runner portion as in the prior art, so it is displayed as product weight / total injection weight. Injection yield is greatly improved. In addition, the man-hours for separating and removing unnecessary portions at the time of releasing the frame are greatly reduced.

  Further, since the filling of the molten metal into each cavity portion is performed through the sprue holes communicated with each cavity portion, the filling process is completed uniformly and in a short time. Therefore, casting defects such as hot water boundaries and non-rotations are unlikely to occur. Moreover, since filling in a short time is possible, it becomes possible to pour a low-temperature molten metal, and defects such as shrinkage and seizure hardly occur.

  In summary, the difference between the conventional casting method and the present means can be summarized as follows. First, the basic structure of the mold cavity is a pouring part, a runner part, a pouring part and a product part in the casting method of the prior art, but in this means, a pouring sump, a pouring hole and a product part, or a sump and pouring hole. The hot water supply section and the product section. In the pouring process, the molten metal is filled in the order of the sprue part, the runner part, the feeder part, and the product part in the casting method of the prior art. It is the order of the order, or the sump, the sprue hole, the feeder part, and the product part, or the order of the sump, the spout hole, the product part, and the feeder part. The cavity portion filled with the molten metal is all the cavity portions in the casting method of the prior art, but in this means, basically the product portion and a part of the sprue hole, or the product portion and the pouring portion and the spout hole. Is part of.

  As described above, the casting method of filling the required cavity portion with the molten metal is not used at all with the large sprue portion and the runner portion in the casting method of the prior art, but using the sump and the plurality of sprue holes on the upper surface of the upper mold. Provided. This casting method can completely solve the problems (1) to (6) of the prior art casting method.

(Means 2)
In a casting method in which molten metal is poured from above into a gas permeable mold having a plurality of product cavities, a puddle is provided at the top of the mold and communicated from the bottom of the puddle to the product cavities and / or feeder cavities. A plurality of sprue holes to be connected, and the plurality of product part cavities and / or feeder cavities are connected by connecting weirs, and the necessary cavity part to be filled with molten metal in the mold cavity in the mold reservoir And a molten metal having substantially the same volume is poured, and the required cavity is filled with the molten metal through the plurality of sprue holes.

  In this means, the mold configuration and the pouring method are almost the same as in means 1, but a mold in which a plurality of product parts and / or hot water parts are connected by a connecting weir is used. The function of the connecting weir is to fill each product part, the hot metal part, and the molten metal hole with the same amount of molten metal, and to make the height of the molten metal remaining in each molten metal hole the same after completion of filling.

  That is, in the means 1, since each product part and the feeder part are separated from each other, there may be a difference in the amount of molten metal filled from the sump through each spout hole, and the height of the molten metal remaining in each spout hole is Not necessarily the same level. Under the worst conditions, an unfilled part may occur in a certain product part and a hot water part.

  By providing a connecting weir like this means, even if there is a difference in the amount of molten metal filled from each spout hole during the pouring process, each product part and the hot water part are connected, so finally each The amount of molten metal filled in can be made the same. That is, the height of the molten metal remaining in each pouring hole is the same level, the molten metal head from the molten metal in the pouring hole acting on each product part and the molten metal part is the same, and replenishment of liquid shrinkage and solidification shrinkage is also the same condition It can be made.

  The shape of the connecting weir may be any shape and size as long as the molten metal flows without solidifying until the pouring is completed and each product part and the hot water part are connected. However, in consideration of the separation process of each product part, the feeder part and the connecting weir after completion of solidification, it is preferable that the shape is as easy as possible to be separated and is small.

  As described above, the filling of each product part and the hot metal part is completed under exactly the same conditions, and the solidification process is a casting method with higher uniformity than that of the means 1 with the same molten metal head made of molten metal in the gate hole.

(Means 3)
The casting method according to means 2, wherein the cross-sectional area of the connecting weir is 10 mm ² or more and 150 mm ² or less.

  The function of the connecting weir is to finally make the amount of molten metal filled in each cavity portion equal, and make the height of the molten metal in the portion of each gate hole the same level. Therefore, it is completely different from the function of the runner part in the casting method of the prior art, that is, to distribute and fill the molten metal from the pouring part into the feeder part or the product part.

  Therefore, the connecting weir does not require a large cross-sectional area as in the prior art gate. It suffices that the function of connecting the respective cavity portions without solidifying until the filling of the molten metal is completed so that the amount of the molten metal filled in each of the cavity portions is the same can be achieved. And after filling is completed and it solidifies, it is better that separation of a product part, a feeder part, and a connection weir is easy.

Therefore, in this means, the cross-sectional area of the connection weir is 10 mm ² or more and 150 mm ² or less. If it is smaller than 10 mm ² , solidification may occur during filling, and if it exceeds 150 mm ² , separation of the product part, the feeder part and the connecting weir after solidification becomes complicated.

(Means 4)
In the casting method according to means 1, the basic structure of the mold cavity is a casting part characterized by comprising a product part, a sump and a sprue hole, or a product part, a hot water part, a sump and a sprue hole. It should be noted that additional cavities such as skein and degassing may be provided as necessary.

(Means 5)
In the casting method according to any one of the means 2 and 3, the basic structure of the mold cavity is a product part, a sump, a sprue hole and a connecting weir, or a product part, a hot water part, a sump, a sprue hole and a connecting weir. It is the casting method characterized by becoming. It should be noted that additional cavities such as skein and degassing may be provided as necessary.

(Means 6)
6. The casting method according to any one of means 1 to 5, wherein the molten metal is filled while the mold is decompressed.

  In this means, the molten metal is filled while the mold is depressurized by the structure of the mold cavity and the pouring method described in any one of means 1 to 5. The action of depressurization is to allow the molten metal poured into the hot water pool to be filled in each product part cavity and the hot-water supply part cavity as uniformly as possible and promptly through each hole. The depressurization may be started before pouring the molten metal into the puddle, or may be started after pouring.

  It is efficient to perform the pressure reduction from the lower part of the mold in accordance with the filling direction of the molten metal, but the pressure can also be reduced from the side surface or the corner of the frame. Moreover, the filling speed | rate of the molten metal from each gate hole can also be controlled by adjusting arrangement | positioning etc. of the decompression hole for decompressing. It is also effective to cover or surround the mold when it is desired to increase the degree of vacuum.

(Means 7)
6. The casting method according to any one of means 1 to 5, wherein the molten metal is filled while the mold is decompressed, and the decompression is continued after filling to promote solidification.

  In this means, the molten metal is filled while reducing the pressure by the mold cavity pouring method and the pouring method described in any one of means 1 to 5, and the pressure reduction is continued thereafter. The pressure reduction for filling the molten metal may be started before pouring the molten metal into the hot water pool or may be started after pouring, as in the means 6. The effect is the same as that of the means 6. The action of decompression after filling is to promote solidification by sucking and discharging the amount of heat of the molten metal by the flow of air in the mold. As is generally known, the metal structure and mechanical properties are improved if the solidification rate of the metal is increased. Therefore, for this purpose, the decompression is continued after the pouring is completed. In this case, it is not necessary to apply a high degree of decompression, and it is efficient to flow a large amount of air into the mold with a low degree of decompression. As a result, the problem (7) of the prior art can be solved.

  The present invention provides a casting method capable of obtaining the following effects.

(1) Molten metal can be filled only in the product portion or in the necessary cavity portions such as the product portion and the hot water supply portion, and the injection yield is greatly improved. (2) Subsequent processes such as unpacking and product separation have been greatly simplified. (3) The molten metal was uniformly distributed and filled into each product part during the pouring process. (4) The filling time of the molten metal into each product part was shortened. (5) Low temperature pouring became possible. (6) Hot water supply to the isolated thick part became easy. (7) After pouring, a rapid solidification rate can be obtained. As a result, defects are hardly generated and the material strength is improved.

The effects of solving the above problems are as follows: (1) The injection yield is greatly improved, and post-processes such as unpacking and product separation are greatly simplified, improving the production efficiency, reducing the energy cost, A reduction of ₂ was obtained. (2) Product quality has been improved by improving the pouring process and the effect of the hot water.

  The best mode for carrying out the invention is obtained by means 7. That is, in a casting method in which molten metal is poured from above into a gas-permeable mold made up of a plurality of product cavities, a hot water puddle is provided on the upper part of the mold, and the product cavity and / or the hot water feeder cavity are formed from the bottom of the hot water puddle. And a plurality of product part cavities and / or feeder part cavities are connected by connecting weirs, and the molten metal having the same volume as the required cavity portion to be filled with the molten metal is provided. It is a casting method in which molten metal is poured into a required cavity through a plurality of sprue holes while the mold is depressurized while the mold is depressurized, and solidification is promoted by continuing depressurization after the completion of filling.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

  A first embodiment is shown in FIGS. FIG. 1 shows the state of the mold cavity, FIG. 2 shows the state during pouring, and FIG. 3 shows the state after pouring. In this embodiment, means 1 and 4 are used to provide a hot water puddle on the upper part of the mold, and to provide a plurality of sprue holes communicating from the bottom surface of the hot water puddle to the product part cavity and / or the hot water part cavity, Explains the casting method in which the molten metal of the same volume as the required cavity portion of the mold cavity to be filled with molten metal is poured into the puddle, and the molten metal is filled into the necessary cavity through the plurality of sprue holes. To do.

  First, a conventional casting method will be described with reference to FIGS. 4 shows the state of the mold cavity 1, and FIG. 5 shows the state after pouring. The mold 2 is a sand mold, and the upper mold 3 and the lower mold 4 are formed on the upper frame 5 and the lower frame 6, respectively, and are placed on the surface plate 7.

  In FIG. 4, C <b> 1 to C <b> 6 indicate the product part 8, and R <b> 1 to R <b> 3 indicate the feeder part 9. That is, six products are included in one frame, and one hot water supply is provided for two products. The mold 2 is provided with a gate 10 and a runner 11 for casting a molten metal 12. Usually, the pouring gate 10 has a large cross-sectional area in order to pour molten metal from all cavities from one place. Further, the runner portion 11 is disposed at the joint of the upper mold 3 and the lower mold 4, that is, at the parting surface 13.

  First, the prior art casting method and its problems will be described with reference to FIGS. The mold is composed of a product part 8, a feeder part 9, a sprue part 10, and a runner part 11, and the molten metal 12 is poured from the sprue part 10 and filled into each product part 8 through the runner part 11. After completion of filling, the frame is released after waiting for solidification by natural cooling. Thereafter, the unnecessary hot-water supply portion 9, the pouring gate portion 10, and the pushway portion 11 other than the necessary product portion 8 are removed and sent to the remelting as a return material, and only the product portion 8 is finished to become a product.

  Such conventional casting methods have the following problems. (1) The injection yield expressed as product part weight / total injection weight is low. In other words, productivity is low and energy costs are high. (2) A great amount of man-hours are required for separating and removing unnecessary portions at the time of releasing the frame. In addition, since the molten metal is filled into a plurality of product cavities while pouring from one spout and branching the runner, (3) even distribution and filling of the molten metal into each product cavities during the pouring process. difficult. (4) The filling time of the molten metal into each product part is long. For this reason, defects such as hot water boundaries and inoperables are likely to occur. In addition, as countermeasures, (5) since hot pouring is performed, defects such as shrinkage and seizure are likely to occur.

  Next, this embodiment will be described. In the mold cavity 1 of FIG. 1, the product parts 8 of C1 to C6 and the feeder parts 9 of R1 to R3 are the same as the mold cavity of the prior art. However, in the present embodiment, the prior art gate 10 and runner 11 are not provided. Instead, a hot water sump 14 is provided at the upper part of the mold 2, and a plurality of sprue holes 15 communicating from the bottom surface of the hot water sump 14 to the respective hot water supply portions 9 are provided. In the present embodiment, an example in which the gate hole 15 communicates with the feeder part 9 will be described. However, even if the gate hole 15 communicates with the product part 8 or the product part 8 and the feeder part 9, the operational effect is almost the same. The same. Moreover, the hot water reservoir 14 and the sprue hole 15 may be molded by molding, or may be molded by cutting or the like after molding. The shape of the hot water reservoir 14 may be a size and an arbitrary shape capable of receiving the molten metal to be poured. Further, the shape of the bottom surface of the hot water reservoir 14 does not need to be a flat surface, and can be a preferable shape for filling the molten metal, such as a gradient toward the pouring hole 15.

  The casting method will be described with this mold configuration. FIG. 2 shows a state during pouring. Total volume 1 including the total volume 1 of the plurality of product parts 8 and the hot water supply parts 9 that are the cavity portions to be filled, and the total volume 2 of the plurality of gate holes 15 up to the height at which the molten metal 12 is finally desired to be filled. Then, the molten metal 12 having substantially the same volume is poured into the water reservoir. The poured molten metal 12 is filled into each feeder 9 through a plurality of gate holes 15 and further filled into the product portion 8.

  FIG. 3 shows the state after pouring. After completion of filling, the molten metal 12 is filled up to a certain height in each gate hole 15. In the present embodiment, since the gate holes 15 are formed in the same cross-sectional area, the height of the molten metal 12 in each gate hole 15 is substantially the same level, but there is a possibility that a slight difference may occur. In the worst case, there is a possibility that unfilling occurs in a certain hot water supply section 9 and product section 8. This can be prevented by keeping the measurement accuracy of the molten metal 12 to be poured into a certain level of accuracy, and taking into account the expansion of the mold 2 and the lifting of the upper mold. Moreover, it can prevent by adjusting arrangement | positioning and cross-sectional area of the gate hole 15, and making the molten metal amount filled from each gate hole 15 as uniform as possible.

  As a result, in the present embodiment, after filling is completed, there is no large sprue portion 10 and runner portion 12 as in the prior art, and only the product portion 8, the feeder portion 9 and the spout hole 15 are part. In addition, each product part 8, the feeder part 9, and the gate hole 15 are separated from each other. Since the cross-sectional area of the plurality of gate holes 15 is small, the total volume of the molten metal 12 is smaller than the volume of the large gate portion + runner portion of the prior art. Therefore, the implantation yield was greatly improved.

  Moreover, since each product part 8, the hot-water supply part 9, and the sprue hole 15 are separated and are made into three blocks, the disassembly after the completion of solidification and the product part 8 can be easily separated and taken out. In addition, since the molten metal 12 is filled into each product part 8 and / or the feeder part 9 through the plurality of sprue holes 15, the molten metal 12 can be uniformly distributed and filled into each product part 8 during the pouring process. The filling time of the molten metal 12 into each product part 8 is shortened. For this reason, it is difficult for casting defects such as hot water boundaries and non-rotations to occur. It is also possible to perform low temperature pouring. The effects such as were obtained.

  It should be noted that it is not preferable for the molten metal to remain on the bottom surface of the puddle so that the amount of pouring is too much to connect the respective sprue holes, both in terms of the injection yield and in terms of the release frame and product part separation. However, it is within the range of variation of the present invention that it remains in the sump beyond the upper surface of each sprue hole when it is slightly too much. Further, it is within the range of variations of the present invention to remain dispersed on the bottom of the hot water pool.

  Next, regarding the casting method of the prior art and the casting method of the first embodiment, a comparison of the injection yield, the injection time and the molding efficiency will be specifically shown.

  First, in the casting method of the prior art, the product weight = 4.5 kg, the number of fillings = 6, the total product weight 27.0 kg, the feeder weight 4.3 kg, the number of feeders = 3, the feeder total weight = 12.9 kg. The gate weight was 4.8 kg, the runner weight was 2.8 kg, and the total injection weight was 47.5 kg. Therefore, the injection yield = 27.0 / 47.5 × 100 = 56.8%. The injection time was 7.6 seconds using an injection gate with a diameter of 4 cm. The molding efficiency is 6 per frame, and this is taken as index 100.

  Next, in Example 1, the product weight = 4.5 kg, the number of fillings = 6, the total product weight 27.0 kg, the feeder weight 4.3 kg, the number of feeders = 3, and the feeder total weight = 12.9 kg. Is the same as the conventional casting method. With 3 spout holes with a diameter of 2.5 cm, the spout hole total weight was 0.41 kg, and the total injection weight was 40.3 kg. Therefore, the injection yield = 27.0 / 40.3 × 100 = 67.0%. The injection time was 5.9 seconds. The index of molding efficiency is 100 because the number of inserts is the same.

  As described above, in Example 1, compared with the casting method of the prior art, the injection yield was improved by about 10.2%, and the injection time was shortened by 1.7 seconds.

  FIG. 6 shows the state of the second embodiment after pouring. In this embodiment, a casting method using means 2, 3 and 5 will be described. The mold cavity 1 has a product part 8 and a hot water supply part 9, and a hot water reservoir 14 and a pouring hole 15 for pouring are provided in the same manner as in the first embodiment. In this embodiment, a mold in which the product parts 8 or the hot water supply parts 9 are connected by the connecting weirs 16 is used. The pouring method is exactly the same as in Example 1.

As can be seen from FIG. 6, after filling the molten metal 12, the product parts 8 or the feeder parts 9 are connected by the connecting weirs 16, so the height of the molten metal in the gate holes 15 is the same. That is, due to the action of the connecting weir 16, the difference in the height of the molten metal 12 in each of the sprue holes 15 that was a slight problem in Example 1 was completely eliminated. As a result, more stable filling than in Example 1 was possible. Note that the connecting weir 16 has a minimum size that allows the molten metal 12 to flow during the filling process, and has a size that allows easy disassembly and product separation after solidification. The size of the connecting weir 16 is optimal when the cross-sectional area is 10 mm ² or more and 150 mm ² or less. If it is smaller than 10 mm ² , solidification may occur in the filling process, and if it exceeds 150 mm ² , product separation becomes complicated. In this embodiment, the thickness is 3 mm × width 20 mm. With this size, product separation when the frame is released is easy.

  In this embodiment, the pouring hole 15 is communicated with the feeder 9 and the molten metal 12 is filled. However, the pouring hole 15 can be communicated with the product part 8 and filled directly from the product part 8 as necessary. . The effect at that time is the same.

  Next, regarding the casting method of the prior art and the casting method of the second embodiment, a comparison of the injection yield, the injection time and the molding efficiency will be specifically shown. The numerical values of the prior art casting method are as described above.

  In the second embodiment, the product weight = 4.5 kg, the number of containers = 6, the total product weight 27.0 kg, the feeder weight 4.3 kg, the number of feeders = 3, and the total feeder weight = 12.9 kg. Same as technology casting. Three sprue holes with a diameter of 2.5 cm, the total spout hole weight = 0.41 kg, the connecting weir is 3 mm thick x 20 mm wide x 150 mm long x 3, the total weir weight = 0.19 kg, total injection weight = 40.5 Kg. Therefore, the injection yield = 27.0 / 40.5 × 100 = 66.7%. The injection time was 5.9 seconds. The index of molding efficiency is 100 because the number of inserts is the same.

  As described above, the second embodiment is almost the same as the first embodiment, and the injection yield is improved by about 9.9% and the injection time is shortened by 1.7 seconds compared with the casting method of the prior art.

  The state after pouring of Example 3 is shown in FIG. In the present embodiment, the casting method using the hot water reservoir 14 and the plurality of sprue holes 15 will be described using the means 2, 3 and 5 in the mold cavity configuration and the pouring method almost the same as in the second embodiment. In this example, the number of fillings per frame was increased to pursue a higher injection yield.

  In FIG. 7, the product parts 8 are C1 to C8. In other words, in the case of Example 2, the number of products contained in the product was increased by 2 to 8 products. Since the large gate part 10 and the runner part 11 used in the prior art in Example 2 can be omitted, the product parts C7 and C8 are added using the space, and the feeder arrangement is changed. is there. The sprue hole 15 is also communicated with the feeder 9 and filled with the molten metal 12 therefrom. Since each feeder 9 is connected by the communication weir 16, the molten metal height of each filling hole 15 after filling is also at the same level. As a result, the number of product parts 8 increased by two, and the injection yield was further improved.

  Next, regarding the casting method of the prior art and the casting method of the third embodiment, the comparison of the injection yield, the injection time and the molding efficiency will be shown. The numerical values of the prior art casting method are as described above.

  In Example 3, the product weight = 4.5 kg, the number of fillings = 8, the total product weight 36.0 kg, the feeder weight 4.3 kg, the number of feeders = 4, the feeder weight = 17.2 kg, the diameter. The total weight of the sprue hole is 0.56 kg with four 2.5 cm sprue holes, the connecting weir is 3 mm thick x 20 mm wide x 150 mm long, the total weight of the connecting weir = 0.19 kg, the total injection weight = It was 53.8 kg. Therefore, implantation yield = 36.0 / 53.8 × 100 = 66.9%. The injection time was 5.9 seconds. The index of molding efficiency is 125 because the number of inserts has increased by two.

  As described above, in this third embodiment, the injection yield was improved by 10.1%, the injection time was shortened by 1.7 seconds, and the molding efficiency was improved by 25% compared with the casting method of the prior art.

  The state after pouring of Example 4 is shown in FIG. In this embodiment, the casting method using the hot water reservoir 14 and the plurality of gate holes 15 will be described using the means 2, 3 and 5 with the mold cavity configuration and the pouring method almost the same as in the third embodiment.

  In this embodiment, there is no feeder part 9 as in the third embodiment, and only the product part 8 is used. Since the hot water supply section 9 has disappeared, the arrangement of the product sections 8 was changed so that the number of packs was 12. The mold 2 allows the hot water reservoir 14 and each product part 8 to communicate with each other through a plurality of sprue holes 15, and the molten metal 12 is filled there from there. However, in order to give the pouring hole 15 the function of the pouring hot water, the upper cross-sectional area of the pouring hole 15 is increased to form the pouring pouring hot water 17. The pouring hot water 17 is used to supply hot water to the product part 8 directly to prevent shrinkage from the upper part. A filter 18 is provided above each gate hole 15 in order to prevent inclusions and the like from entering.

  An effect is demonstrated by this structure. When the molten metal 12 is weighed and poured into the hot water reservoir 14, the molten metal 12 is filled into the product portion 8 through the gate hole 15. In addition to the volume of the product portion 8, the amount of molten metal to be poured is approximately the same as the volume obtained by adding the amount by which the pouring gate 17 is formed above the pouring hole 15. Since each product part 8 is connected by the connection weir 16, the molten metal height of each pouring hole 15 after filling is the same level. Thereafter, hot water supply for preventing the shrinkage nest of the product portion 8 is performed by the pouring gate 17 at the upper part of the pouring hole 15.

  In addition, the pouring hot water supply 17 of the upper part of the pouring hole 15 is provided in direct communication with the upper part of the product part 8 compared with the pouring hot water part 9 in the case of FIG. Therefore, a small volume is sufficient. Moreover, since the pouring gate 17 can be provided in the part with the highest pouring effect according to the shape of the product part 8, it is efficient. Further, it is not always necessary for the connecting weirs 16 to connect all the product parts 8 as shown in FIG. 8. All the product parts 8 are connected by the minimum connecting weirs 16, and the molten metal height of each sprue hole 15 after filling is completed. Should be at the same level.

  As a result of the above, the conventional technique had 6 inserts, but in the present example, 12 inserts, and the implantation yield was greatly improved. Further, the increase in the number of inserts reduces the number of casting frames necessary for obtaining a predetermined product, resulting in a significant reduction in man-hours.

  Next, regarding the casting method of the prior art and the casting method of the fourth embodiment, the comparison of the injection yield, the injection time and the molding efficiency will be specifically shown. The numerical values of the prior art casting method are as described above.

  In this Example 4, the product weight = 4.5 kg, the number of fillings = 12, the total product weight 54.0 kg, the pouring hole pouring hot water into four pouring holes having a diameter of 2.5 cm, and the pouring hole total weight = 8. 24 Kg, the connecting weirs were 3 mm thick × 20 mm wide × 20 mm long × 17, the total weight of the connecting weir = 0.14 kg, and the total injection weight = 62.4 kg. Therefore, implantation yield = 54.0 / 62.4 × 100 = 86.6%. The injection time was 4.2 seconds. The index of molding efficiency is 200 because the number of inserts has increased by six.

  As described above, in Example 4, the injection yield was improved by 29.8%, the injection time was shortened by 3.4 seconds, and the molding efficiency was improved by 100% as compared with the casting method of the prior art.

  FIG. 9 shows a state after pouring of Example 5. In this embodiment, the casting method using the hot water reservoir 14 and the plurality of gate holes 15 with the configuration of the mold cavity and the pouring method almost the same as those of the embodiment 4 will be described using the means 2, 3 and 5.

  In the present embodiment, description will be made by taking an example of casting of spheroidal graphite cast iron, which is a typical material of cast iron. In the case of cast iron, since expansion occurs due to graphite precipitation during solidification, it is possible to compensate for liquid shrinkage and solidification shrinkage by the expansion, and it may be possible to cast a casting without a shrinkage defect without a feeder. . In particular, by pouring at a low temperature, liquid shrinkage is reduced and the possibility is increased. In this example, the molten metal was poured at 1300 ° C., which is 100 ° C. lower than the normal pouring temperature of about 1400 ° C. Such low-temperature pouring is possible because a casting method in which the hot water reservoir 14 and the sprue hole 15 are provided in the present invention and the product portion 8 is directly filled with the molten metal becomes possible. As a result, the shrinkage defect does not occur even without a feeder.

  As a result, it is possible to cast 16 product parts 8 without providing the gate 17 in the gate hole 15 as in the fourth embodiment. The injection yield was further improved because the feeder 9 and the feeder 17 were eliminated.

  Next, regarding the casting method of the prior art and the casting method of the fifth embodiment, the comparison of the injection yield, the injection time and the molding efficiency will be shown specifically. The numerical values of the prior art casting method are as described above.

  In this Example 5, the product weight = 4.5 kg, the number of fillings = 12, the total product weight 54.0 kg, the diameter of the 4 cm gate hole, the total gate hole weight = 1.65 kg, and the connecting weir is thick. The length was 3 mm × width 20 mm × length 20 mm × 17. The total weight of the connecting weirs was 0.14 kg and the total injection weight was 55.8 kg. Therefore, implantation yield = 54.0 / 55.8 × 100 = 96.8%. The injection time was 3.9 seconds. The index of molding efficiency is 200 because the number of inserts has increased by six.

  As described above, in Example 5, the injection yield was improved by 40.0%, the injection time was shortened by 3.7 seconds, and the molding efficiency was improved by 100% as compared with the casting method of the prior art.

  FIG. 10 shows the state of the sixth embodiment after pouring. In this embodiment, the means 6 and 7 are used, and the mold cavity configuration and the pouring method similar to those of the embodiment 5 are used. A casting method will be described in which decompression is continued after filling is completed to promote solidification.

  In this example, a decompression box 19 was disposed below the lower mold 4, and the molten metal was filled while the mold 2 was decompressed by the decompression device 20. Depressurization was started after pouring the molten metal 12 into the hot water reservoir 14. The molten metal 12 poured into the hot water reservoir 14 is filled into the product portion 8 through the gate hole 15. At this time, since the pressure is reduced from the lower part of the mold 2, the molten metal 12 is filled more rapidly than in the case where there is no pressure reduction. By changing the arrangement and cross-sectional area of the plurality of decompression holes 21 of the decompression box 19, the filling speed from the plurality of gate holes 15 can be made uniform.

  The degree of decompression is effective in increasing the filling speed even at a low value excluding the back pressure in the mold during pouring. In this example, the pressure was set to 0.01 MPa. In reducing the pressure, covering the open portion of the mold with some non-venting member (not shown) is also effective in obtaining a stable degree of pressure reduction.

  After filling the molten metal, continue to reduce the pressure. In this case, the product part is actively cooled by flowing air into the mold rather than the degree of decompression. Further, the size and arrangement of the decompression holes 21 of the decompression box 19 can be adjusted so that the cooling rates of the product parts 8 do not become uneven.

  As a result, the product portion 8 has a high solidification rate, and a hard solidified skin is formed at an early stage. Therefore, in this material, high solidification expansion force generated when solidification progresses and graphite begins to precipitate from the inside can be received and used by this hard solidification skin, and the effect of preventing the occurrence of shrinkage can be enhanced. it can. With this effect, it is possible to establish a casting method that does not have a feeder more reliably than in the fifth embodiment. As is generally known, the metal structure was improved by increasing the cooling rate, and an excellent material strength was obtained.

  Next, regarding the casting method of the prior art and the casting method of Example 6, the comparison of the injection yield, injection time and molding efficiency will be shown. The numerical values of the prior art casting method are as described above.

  In this Example 6, the product weight = 4.5 kg, the number of fillings = 12, the total product weight 54.0 kg, the diameter of the spout holes of 2.5 cm, the total diameter of the sprue hole = 1.65 kg, and the connecting weir is thick. The length was 3 mm × width 20 mm × length 20 mm × 17. The total weight of the connecting weirs was 0.14 kg and the total injection weight was 55.8 kg. Therefore, implantation yield = 54.0 / 55.8 × 100 = 96.8%. The injection time was 3.3 seconds. The index of molding efficiency is 200 because the number of inserts has increased by six.

  As described above, the sixth embodiment is the same as the fifth embodiment, and the injection yield is improved by 40.0%, the injection time is reduced by 4.3 seconds, and the molding efficiency is improved by 100%, compared with the casting method of the prior art. did.

In addition, since the product portion was cooled at a high speed by the reduced pressure, shrinkage defects were reduced with a hard solidified skin, and the structure became dense, so that the mechanical properties were also improved. Specifically, a tensile test was performed on a test piece cut out from the product, and the following results were obtained. That is, the tensile strength = 52.6 kg / mm ² and the elongation = 11.4% according to the casting method of the prior art, but in this example, the tensile strength = 61.5 kg / mm ² and the elongation = 13.3. 4%.

It is a figure which shows the state of the mold cavity of Example 1 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the state in the pouring of Example 1 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the state after the pouring of Example 1 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the mold cavity of a prior art. (A) is a plan view and (B) is a side view. It is a figure which shows the state after pouring of a prior art. (A) is a plan view and (B) is a side view. It is a figure which shows the state after the pouring of Example 2 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the state after the pouring of Example 3 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the state after the pouring of Example 4 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the state after the pouring of Example 5 of this invention. (A) is a plan view and (B) is a side view. It is a figure which shows the state after the pouring of Example 6 of this invention. (A) is a plan view and (B) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold cavity 2 Mold 3 Upper mold 4 Lower mold 5 Upper frame 6 Lower frame 7 Surface plate 8 Product part cavity or product part 9 Feeder part cavity or feeder part 10 Suction part cavity or feeder part 11 Runway Cavity or pouring part 12 Molten metal 13 Parting surface 14 Pouring pool 15 Pouring hole 16 Connecting weir 17 Pouring hot water 18 Filter 19 Decompression box 20 Depressurizing device 21 Depressurizing hole

Claims (7)

  In a casting method in which molten metal is poured from above into a gas permeable mold having a plurality of product cavities, a puddle is provided at the top of the mold and communicated from the bottom of the puddle to the product cavities and / or feeder cavities. A plurality of sprue holes are provided, and a molten metal having a volume substantially equal to a required cavity portion to be filled in the mold cavity is poured into the puddle, and the necessary cavities are passed through the plurality of sprue holes. A casting method characterized by filling molten metal into a metal.   In a casting method in which molten metal is poured from above into a gas permeable mold having a plurality of product cavities, a puddle is provided at the top of the mold and communicated from the bottom of the puddle to the product cavities and / or feeder cavities. A plurality of sprue holes to be connected, and the plurality of product part cavities and / or feeder cavities are connected by connecting weirs, and the necessary cavity part to be filled with molten metal in the mold cavity in the mold reservoir A casting method characterized by pouring a molten metal having substantially the same volume as that of the molten metal and filling the required cavity through the plurality of gate holes. The casting method according to claim 2, wherein a cross-sectional area of the connection weir is 10 mm ² or more and 150 mm ² or less.   2. The casting method according to claim 1, wherein the basic structure of the mold cavity comprises a product part, a sump and a sprue hole, or a product part, a hot water part, a sump and a sprue hole.   4. The casting method according to claim 2, wherein the basic structure of the mold cavity is a product part, a sump, a sprue hole and a connecting weir, or a product part, a hot water part, a sump, a sprue hole and a connecting weir. A casting method characterized by   6. The casting method according to claim 1, wherein the molten metal is filled while the mold is decompressed. 6. The casting method according to claim 1, wherein the molten metal is filled while the mold is decompressed, and the decompression is continued after the filling is completed to promote solidification.