KR20040102748A - Cooling Apparatus for Microstructural Refinement of Cast Material in the Process of Evaporative Pattern Casting - Google Patents

Abstract

PURPOSE: A cooling apparatus is provided to create a microscopic structure by controlling a cooling speed at a wanted local position among casting portions in evaporative pattern casting regardless of casting method and temperature, to installing a lost-form casting apparatus which is not so different from an existing one, to cope with a change of casting item, shape and casting method easily. CONSTITUTION: A microscopic structure among portions of a casting material is installed in the vicinity of a model surface. A cooling mold(240) has a coolant passage therein. A coolant introducing portion(210a) is provided to supply a coolant from the outside of a flask in which casting is performed. An introducing pipe(220a) transfers the coolant introduced from the coolant introducing portion to the cooling mold. A discharging pipe(220b) discharges the coolant which is passed through the cooling mold. A coolant discharging portion discharges the coolant passed through the discharging pipe outside the flask.

Description

Cooling Apparatus for Microstructural Refinement of Cast Material in the Process of Evaporative Pattern Casting}

The present invention relates to a cooling device, and more particularly, to a cooling device for miniaturizing a structure by controlling a cooling rate at a desired local position of a casting part in a burnout model casting method.

Evaporative pattern casting can be used to produce existing sand castings because of its eco-friendly advantages, economical efficiency, and near net shape to the final product, which requires almost no final process such as machining. It is attracting attention as an alternative casting method.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the general burnout model casting method. In the burn-out model casting method, first, a model 100 is formed which is molded into the same shape as a casting product to be manufactured using expanded polystyrene (EPS; Expandable Polystyrene) or polymethyl methacrylate (PMMA), which is a raw material such as styrofoam. If the figure 110 is applied to the surface of the model 100, then buried in a pointless binder (120), which is a casting sand without a binder (binder), and the molten metal 130 is injected, The embedded model 100 is vaporized by the heat of the molten metal 130 and discharged into the sand, and the molten metal injected into the space is filled to obtain a desired casting. In the general casting method, the part where the molten metal is filled is the cavity and the mold is composed of sand with coking force.However, in the vanishing model casting, the part where the molten metal 130 is filled is composed of the model 100. It is filled with the pointless binder 120 which cannot form a mold, ie, no coking force. Therefore, the pointless binder 120 supporting the model 100 has fluidity, and thus has a characteristic of continuously moving until the molding process of the vibration charging method is completed. Because of this characteristic, a technique for installing a device in the mold for controlling the cooling rate of the casting and the like has not yet been implemented.

On the other hand, the molten metal injected by the burn-off model casting method proceeds while decomposing and discharging the model using the thermal energy and replacing the spot. Therefore, while the temperature of the tip of the molten metal drops preferentially, the molten metal is injected in a relatively laminar flow form. In the existing cavity mold, the cooling rate and the solidification form of the molten metal depend on the shape of the casting. In the vanishing model casting method, the cooling rate and the solidification form of the molten metal are greatly influenced by the moving direction of the molten metal and the distance from the inlet. In particular, the effect is more pronounced when the vanishing model casting method is applied to a low melting point alloy such as an aluminum alloy.

In the existing burnout model casting method, when a casting requiring localization of the microstructure is to be produced, the casting method is designed so that the micronized portion is positioned at the final reach of the melt tip, or the thermal conductivity is higher than that of the existing casting sand. A method of replacing with good fillers was used. However, in the former case, there are many problems in the application due to the poor management of the injection temperature, the insufficient filling of the melt due to excessive low temperature injection, the poor surface diameter, and the limitation of the casting box. In the latter case, the overall cooling effect is reduced. It was difficult to solve the problem because of the way to plan.

In the conventional vane casting method, various defects have occurred due to difficulty in controlling the cooling rate and attempts thereof.

Accordingly, the technical problem to be achieved by the present invention is to control the cooling rate at a desired local position in the casting site without being restricted by the casting method and the injection temperature in casting of aluminum alloy using the vanishing model casting method. It is to provide a cooling device for tissue micronization that can achieve the size of the dendrite and finer gap of the dendrite.

Another technical problem of the present invention is to provide a cooling apparatus for tissue miniaturization that can be installed and used without making a large change to the existing burnout model casting apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the general burnout model casting method.

Figure 2 is a schematic diagram showing a cooling apparatus for tissue micronization according to an embodiment of the present invention.

Figure 3 is a view for explaining the process of performing a burn-up model casting process in a flask equipped with a microstructured cooling apparatus according to an embodiment of the present invention.

Explanation of reference numbers for the main parts of the drawings

100: Model

110: figure material

120: pointless binder

130: molten metal

200: flask

210a: coolant inlet

210b: coolant outlet

220a: fixed inlet pipe

220b: fixed discharge pipe

230: articulated metal hose

240: cooling mold

250: hole formed in the fixed inlet pipe

310: Model of the casting part that wants the microstructure

In order to achieve the above technical problem, the present invention provides a cooling apparatus for microstructured casting, which is used in the burnout model casting method, and is installed in the vicinity of the model surface of the desired portion of the microstructure among the sites of the casting, and has a coolant therein. A cooling mold having a passage; A coolant inlet for receiving the coolant from the outside of the flask where a casting process is performed; An inlet pipe for transferring the coolant introduced from the coolant inlet to the cooling mold; A discharge pipe for discharging the coolant passing through the cooling mold; And a coolant discharge part for discharging the coolant passing through the discharge pipe to the outside of the flask.

In the present invention, the inlet pipe and the discharge pipe, respectively, the fixed pipe located a predetermined distance away from the cooling mold; One end thereof is connected to the hole of the fixed pipe, and the other end thereof is connected to the coolant passage of the cooling mold to freely move the cooling mold to a desired position of the casting model, and at the same time, fix the position of the cooling mold. It is preferable that the multi-joint metal hose to serve to support the.

Further, in order to more easily adjust the position of the cooling mold, it is more preferable that a plurality of holes of the fixed pipe are formed at different positions, and a sealing means for not being used among the holes.

On the other hand, as long as the cooling mold is to increase the cooling capacity, any material may be used, but as an example, a copper alloy may be used.

The inlet and the outlet, respectively, a fitting device for connecting with a hose for supply and discharge of coolant from the outside; It is preferable to further include a locking device to prevent the coolant remaining in the inlet and outlet pipes when the hose is attached and detached.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

Figure 2 is a schematic diagram showing a cooling apparatus for tissue micronization according to an embodiment of the present invention. For the sake of clarity, the burnout model casting flask 200 is shown by cutting. Referring to Figure 2, the cooling apparatus of the present invention, the cooling die 240 having a coolant passage (not shown) in its own, the coolant inlet for receiving a coolant from the outside of the flask 200 is formed casting process 210a, an inlet pipe 222a for transferring the coolant introduced from the coolant inlet 210a to the cooling mold 240, a discharge pipe 222b for discharging the coolant passing through the cooling mold 240, and discharge It consists of the coolant discharge part 210b for discharging the coolant which passes through the piping 22b to the exterior of the flask 200. The coolant may be used without limitation as long as it is in a fluid form, and cooling water was used in this embodiment. Cooling mold 240 is installed in close proximity to the model surface of the portion of the desired part of the microstructure of the casting (not shown). Inlet pipe 222a, the fixed inlet pipe 220a located near the inner wall of the flask 200 to some extent away from the cooling mold 240, and its one end and the hole 250 of the fixed inlet pipe 220a It is connected and the other end is composed of a multi-joint metal hose 230 is connected to the coolant passage of the cooling mold (240). The discharge pipe 222b also includes a fixed discharge pipe 220b and a multi-joint metal hose 230 in the same manner. Here, "fixed" means that its shape is not deformed or the position is not changed. Since the articulated metal hose 230 included in the inlet and outlet pipes 222a and 222b bends when a force is applied, the cooling mold 240 freely moves to the desired position of the casting model. In addition, since the articulated metal hose 230 is bent by deformation and fixed to a certain position, the multi-joint metal hose 230 may support a cooling mold 240 because it can support a certain weight.

In the present embodiment, the arrangement shape and the number of molds are specified, but the arrangement shape and the number of molds can be modified or deleted depending on the shape of the flask (cuboid or cylindrical) and the arrangement of the model according to the casting method. Of course.

On the other hand, in the apparatus of the present embodiment, the coolant inlet 210a and the coolant outlet 210b have an inner diameter of approximately 20 to 30 mm, and are connected to a fitting device (not shown) to be connected to a hose for supplying and discharging the coolant from the outside. And, when the attachment and detachment of such a hose has a locking device (not shown) so that the coolant remaining in the inlet and outlet pipes (222a, 222b) do not leak. Since the fitting device and the locking device are not so different from those commonly used in the supply and discharge equipment of fluid, a separate description thereof will be omitted.

The fixed inlet and outlet pipes 220a and 220b installed inside the flask 200 use steel pipes for general use. In addition, the fixed inlet and outlet pipes (220a, 220b) is formed with a number of holes 250, which is connected to the articulated metal hose 230, if necessary to install a cooling jig including a cooling mold (240) Done.

On the other hand, the fixed inlet and outlet pipes (220a, 220b) is formed with a plurality of holes 250 in different positions, it is possible to connect the articulated metal hose 230 at various heights. Among the plurality of holes, the other holes except for being connected to the articulated metal hose 230 are sealed by the sealing means. These holes 250 allow the height of the cooling mold 240 to be easily adjusted. If the hole 250 is sealed without connecting the articulated metal hose 230, the flask 200 of FIG. 2 may be used as a general purpose flask.

Cooling mold 240 is made of a copper alloy to increase the cooling capacity, to create a circulation path (not shown) of the coolant therein to exhibit a cooling effect as the coolant is introduced and discharged. The cooling mold 240 is manufactured in various forms according to the cooling portion of the casting.

Figure 3 is a view for explaining the process of performing a burn-up model casting process in a flask equipped with a microstructured cooling apparatus according to an embodiment of the present invention. For clarity of illustration, a portion of the flask 200 is shown cut away. 3, only one cooling mold 240 is shown on the assumption that only one place of the casting is cooled. First, the cooling mold 240 is installed in close proximity to the surface of the model 310 of the casting portion for which the microstructure is desired. At this time, care should be taken so that the cooling mold 240 does not come into close contact with the surface of the model 310. If the cooling mold 240 is in close contact with the surface of the mold 310 of the casting part, fusion occurs between the casting and the cooling mold 240 during casting, or the cooling mold 240 affects the discharge of the model decomposition gas. This can be caused by a problem of casting failure. Subsequently, after the molding is completed using the pointless binder 120, the coolant inlet 210a and the coolant outlet 210b are externally provided so that the coolant can circulate through the cool mold 240 before casting is injected. Connect to coolant supply and discharge hoses respectively. When the coolant is circulated, the coolant is connected to the coolant inlet 210a, the fixed inlet pipe 220a, the articulated metal hose 230 for the fixed inlet pipe, the coolant passage in the cooling die 240, and the articulated metal hose for the fixed discharge pipe. 230, the fixed discharge pipe 220b and the coolant discharge part 210b are sequentially passed. Thus, when the molten metal is injected in a state where the preparation for cooling is completed, the solidification speed of the portion in contact with the cooling mold 240 among the unsolidified castings after injection is increased. Therefore, in the case of aluminum alloy, the structure fineness of a desired part can be realized, such as the Dendrite Arm Space (DAS) is reduced.

The microstructured cooling device of the present invention as described above can be configured to be detachably attached to each of the parts, it can also be mounted variably according to the working conditions.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

According to the present invention as described above, the following effects can be obtained.

First, there is an effect that can achieve a refinement of the tissue by controlling the cooling rate of the desired portion in the casting without being limited by the casting method and injection temperature. In practice, in the case of a cylinder header, which is one of automobile castings, the area in contact with the cylinder is required to be dense and finely structured, so that the management of the Dendrite Arm Space (DAS) is an important factor. The reality is that it is difficult to access easily.

Second, the device of the present invention can be installed without major changes in the existing burnout model casting apparatus, and can also be used and not used as needed, and can be applied to various processes.

Third, it is easy to cope with changes in casting items, shapes and casting methods. In this case, it is possible to easily cope with the deformation of the articulated metal hose and the use of holes formed at various positions of the pipe pipe.

Claims (5)

In the cooling apparatus for microstructure of the casting in the vanishing model casting method, A cooling mold installed near the model surface of a desired portion of the microstructure among the portions of the casting, and having a coolant passage therein; A coolant inlet for receiving the coolant from the outside of the flask where a casting process is performed; An inlet pipe for transferring the coolant introduced from the coolant inlet to the cooling mold; A discharge pipe for discharging the coolant passing through the cooling mold; A coolant discharge part for discharging the coolant passing through the discharge pipe to the outside of the flask; Cooling apparatus for microstructure of the casting having a. The method of claim 1, wherein the inlet and outlet pipes, respectively: A fixed pipe spaced apart from the cooling mold by a predetermined distance; One end thereof is connected to the hole of the fixed pipe, and the other end thereof is connected to the coolant passage of the cooling mold to freely move the cooling mold to a desired position of the casting model, and at the same time, fix the position of the cooling mold. Multi-joint metal hose to serve to support the; Cooling apparatus for microstructure of the casting, characterized in that consisting of. The method according to claim 2, wherein the plurality of holes of the fixed pipe is formed in a different position, so as to more easily adjust the position of the cooling mold, characterized in that it further comprises a sealing means for not using among the holes. , Chiller for microstructure of castings. The cooling apparatus for microstructure of the casting according to claim 1, wherein the cooling mold is made of copper alloy to increase the cooling ability. The method of claim 1 wherein the inlet and outlet are respectively: A fitting device for connecting with a hose for supplying and discharging the coolant from the outside; Locking device to prevent the coolant remaining in the inlet and outlet pipes when the hose is attached and detached; Cooling apparatus for microstructure of the casting, characterized in that it further comprises.