KR101529234B1 - Method of casting and apparatus of casting - Google Patents

Abstract

The present invention relates to a casting method capable of minimizing casting defects, minimizing casting defects, and omitting a post-casting process, and a casting apparatus for realizing the casting method. In order to precisely control the position, curvature and liquid fraction of a solid- A method for casting a molten metal capable of filling a space, the method comprising: dividing the molten metal and injecting the molten metal sequentially into the casting space, wherein the molten metal is discontinuously injected a plurality of times with an injection interval, And an upper surface of the non-solidified liquid of the molten metal housed in the mold is set so as to be in contact with the mold without being separated from each other during the injection of the molten metal a plurality of times, and a casting apparatus embodying the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a casting method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method and a casting apparatus embodying the same. More particularly, the present invention relates to a method of casting a sound unit part with a high casting recovery rate and minimized casting defects, and a casting apparatus embodying the same.

In the conventional static shape casting process, the entire molten metal is injected at one time, and after the solidification is completed, the casting is taken out. In the existing casting process, the casting design is used to install shrinkage balls, potholes, runners, etc. in order to induce shrinkage balls, which are essential in the process of solidification from liquid to solid due to density difference between liquid and solid, And a casting having a shape is manufactured through a post-process in which these are separated from the casting. According to this, there is a problem that the casting recovery rate, which is the ratio of the casting to the total casting amount, is as low as about 60%, the additional cost due to the post-processing, and the process time are required.

It is an object of the present invention to provide a casting method and a casting apparatus using the casting method which can solve the various problems including the above problems and can eliminate the post casting process with a high casting recovery rate and minimized casting defects. However, these problems are exemplary and do not limit the scope of the present invention.

A casting method according to one aspect of the present invention is provided. The casting method is a casting method for injecting a molten metal capable of filling a casting space formed in a metal mold to precisely control the position, curvature and liquid fraction of a solid-liquid interface, wherein the molten metal is divided and injected sequentially into the casting space And injecting a plurality of times in a discontinuous manner at an injection interval. The injection interval is set so that the upper surface of the molten metal contained in the mold in the non-solidified liquid phase can be contacted without being separated from the mold while the molten metal is injected a plurality of times.

In the casting method, the step of dividing the molten metal and injecting the molten metal into the casting space sequentially, wherein the step of injecting the molten metal discontinuously a plurality of times with an injection interval is performed by controlling the injection rate, the injection amount, And / or adjusting the injection temperature. At this time, by controlling at least one of the liquid amount of the molten metal charged in the casting space, the position of the solid-liquid interface of the molten metal, and the curvature, it is possible to suppress the occurrence of shrinkage holes in the casting.

In the casting method, the step of dividing the molten metal and injecting the molten metal sequentially into the casting space, wherein the injecting the molten metal a plurality of times in a discontinuous manner with an injection interval, The molten metal may be divided and injected into the casting space sequentially so that the curvature of the solid-liquid interface of the metal gradually decreases.

In the casting method, the step of dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the step of discontinuously injecting the molten metal a plurality of times with an injection interval is performed by dividing the molten metal, wherein at least one of the divided molten metals Dividing the divided molten metal so as to have different capacities from at least one of the other molten metals, and sequentially injecting the divided molten metal into the casting space, wherein the divided molten metal is injected a plurality of times at an interval .

In the casting method, the step of dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the step of discontinuously injecting the molten metal a plurality of times with an injection interval is performed by dividing the molten metal, wherein at least one of the divided molten metals Dividing the divided molten metal so as to have a different capacity from at least one of the other molten metals and sequentially injecting the molten metal having a relatively larger capacity first and injecting the relatively smaller amount of the molten metal later, Injecting a plurality of times in a discontinuous manner at an injection interval.

In the casting method, the step of dividing the molten metal and injecting the molten metal sequentially into the casting space, wherein the molten metal is injected a plurality of times in a discontinuous manner at an injection interval, And injecting a plurality of times at an injection interval discontinuously.

In the casting method, the metal mold may include an adiabatically coated metal mold, and may further include a degassing step before the step of injecting the molten metal.

A casting apparatus according to another aspect of the present invention is provided. The casting apparatus is an apparatus for implementing the casting method, and is a device for injecting molten metal capable of filling a casting space formed in a mold. The main casting apparatus includes a main chamber capable of accommodating the molten metal, a nozzle communicating directly with a hole formed in the main chamber and protruding from a lower portion of the main chamber to provide a flow path for entering and exiting the molten metal, And the molten metal is divided into a plurality of portions in the casting space by sequentially opening and closing a hole formed in the main chamber, and the molten metal contained in the molten metal, And a controller for controlling the movement of the stopper so that the upper surface of the liquid can be discontinuously injected at an injection interval set so as to be in contact with the mold without being separated.

According to an embodiment of the present invention as described above, a casting method in which a casting recovery rate is high, casting defects are minimized, and a post-casting process can be omitted, and a casting apparatus for implementing the same can be provided. Of course, the scope of the present invention is not limited by these effects.

1 is a flow chart illustrating a casting method according to embodiments of the present invention.
2 is a diagram illustrating a casting apparatus and a mold for implementing a casting method according to embodiments of the present invention.
3 is a schematic diagram illustrating a casting method according to embodiments of the present invention.
4 is a flowchart illustrating a casting method according to an embodiment of the present invention.
5 is a flowchart illustrating a casting method according to another embodiment of the present invention.
FIG. 6 is a graph illustrating the shape of a shrinkage cavity in a cast material implemented according to an experimental example of the present invention. FIG.
7 is a diagram illustrating a cross-section of cast materials implemented in accordance with an experimental example of the present invention.
8 is a graph illustrating an aspect of the casting recovery rate in a cast material implemented according to an experimental example of the present invention.
9 is a graph showing measurement results of dendrite arm spacing (DAS) in a cast material implemented according to an experimental example of the present invention.
10 is a graph illustrating the measurement results of an X-ray fluorescence analyzer (XRF) showing the aspect of silicon content in a cast material implemented according to an experimental example of the present invention.
11 is a graph illustrating the aspect of the hardness in the cast material implemented according to the experimental example of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, The present invention is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thickness and size of each layer are exaggerated for convenience and clarity of explanation.

Like numbers refer to like elements throughout the specification. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention should not be construed as limited to the particular shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing.

FIG. 1 is a flow chart illustrating a casting method according to embodiments of the present invention. FIG. 2 is a diagram illustrating a casting apparatus and a mold for implementing the casting method according to the embodiments of the present invention. Fig. 2 is a diagram schematically illustrating a casting method according to embodiments of the invention.

1 and 2, a casting method according to an embodiment of the present invention is a casting method for casting a molten metal 71 capable of filling a casting space 85 formed in a mold 80 , And the step of dividing molten metal 71 and injecting the molten metal 71 into the casting space 85 sequentially, but discontinuously injecting the molten metal 71 a plurality of times with an injection interval.

A casting method according to an embodiment of the present invention may include, for example, injecting a first molten metal, at least a portion of the first molten metal solidifies without injecting additional molten metal during a first molar filling interval Step, injecting a second molten metal, and at least a portion of the second molten metal solidify without injecting additional molten metal during the second molar injection interval, and in a similar manner steps (N-1) th molten metal is injected without further injection of molten metal during the (N-1) th injection interval, The casting space 85 of the mold 80 can be filled with the cast product by performing the step of at least partly solidifying and the step of injecting the Nth molten metal. Here, N is a positive integer of 2 or more.

The first molten metal to the Nth molten molten metal may have the same capacity. In this case, in the casting method according to an embodiment of the present invention, the molten metal 71 to be filled in the casting space 85 is divided into a predetermined amount and the divided molten metal is sequentially injected into the casting space 85, And a step of discontinuously injecting a plurality of times at intervals. Such a casting method is hereinafter referred to as a casting method of a metering injection method.

At least one of the first molten metal to the Nth molten metal may have at least a different capacity from the other molten metal. In this case, the casting method according to an embodiment of the present invention is characterized in that the molten metal 71 to be filled in the casting space 85 is divided, and at least one of the divided molten metals is divided into at least the other And a step of sequentially injecting the divided molten metal into the casting space 85 at a plurality of intervals while discontinuously injecting the molten metal at an injection interval. Hereinafter, this is referred to as a casting method of a variable injection method.

Particularly, among the casting methods of the variable injection method, the molten metal 71 to be filled in the casting space 85 is divided, and at least one of the divided molten metals is mixed with at least one of the divided molten metals A casting method in which molten metal having a relatively larger capacity is firstly injected and molten metal having a relatively smaller capacity is injected in succession so as to be injected a plurality of times in a discontinuous manner at an injection interval, The generation of shrinkage holes can be suppressed more effectively.

The casting method according to an embodiment of the present invention is a method of casting a casting mold in which the injection speed, the injection amount, the injection interval, and the injection temperature, which are injected into the mold 80 according to the solidification rate of the molten metal 71, Controlling at least one of the liquid amount of the molten metal 71 filled in the casting space 85, the position of the solid-liquid interface of the molten metal 71, and the curvature. In particular, this casting method will be referred to as Interface-controlled Progressive Casting (IPC) hereinafter.

1 to 3, a casting method according to an embodiment of the present invention includes the steps of dividing molten metal 71 and sequentially injecting the molten metal 71 into the casting space 85, The upper surface of the molten metal 71 contained in the mold 80 is not separated from the mold 80 while the molten metal 71 is injected a plurality of times, And can be set to be in contact with each other.

The casting method according to an embodiment of the present invention is characterized in that the curvature of the solid-liquid interface (S / L) of the molten metal 71 contained in the mold 80 is sequentially , The molten metal 71 may be divided and injected into the casting space 85 sequentially, and the casting may be performed discontinuously plural times with an injection interval.

For example, referring to FIG. 3 (a), a first molten metal having a predetermined capacity is injected into the casting space of the mold 80, and at least a part of the first molten metal Can be kept coagulated. In this case, at the point in time when the first injection interval has passed, the first metal for receiving the first metal contained in the metal mold 80 may be divided into a solidified solid phase 71_1S and a liquid phase 71_1L that has not yet solidified, And the solid-liquid interface S / L of the liquid phase 71_1L may have a first curvature.

Referring to FIG. 3 (b), after the first filling interval, a second filling metal having a predetermined capacity is injected into the casting space of the mold 80, and subsequently, At least a part of the secondary-use metal can be kept coagulated. In this case, at the point in time when the second injection interval has elapsed, the first chargeable metal contained in the metal mold 80 exists as a solid phase 71_1S in which all or part of the solidified metal is solidified, Liquid interface 71_2S of the solid phase 71_2S and the solid phase 71_2L of the solid phase 71_2S and the solid-liquid interface S / L of the liquid phase 71_2L may have the second curvature.

Referring to FIG. 3 (c), after the third filling interval, the third filling metal having a predetermined capacity is injected into the casting space of the mold 80, At least a part of the third molten metal can be kept solidified. In this case, at the point of time when the third injection interval has elapsed, the second molten metal contained in the metal mold 80 exists as a solid phase 71_2S in which all or part of the molten metal is solidified, The liquid phase 71_3S of the solid phase 71_3S and the solid phase 71_3L of the solid phase 71_3S and the solid phase interface S / L of the liquid phase 71_3L may have the third curvature.

The inventor of the present invention has found that during the injection of the molten metal 71 a plurality of times, the upper surface of the molten metal 71 contained in the molten metal 71 can be contacted without being separated from the mold 80 3), it was confirmed that the generation of the shrinkage cavity can be suppressed or minimized when the above-mentioned injection interval is set.

For example, the first main injection interval interposed between the step of injecting the first molten metal and the step of injecting the second molten metal may be performed in a state where the first molten metal contained in the mold 80 is not solidified The upper surface of the liquid phase 71_1L can be set so as to be in contact with the mold 80 without being separated from it. If the second molten metal is injected at the time when the first molten metal is injected, the solidified liquid phase 71_1L of the molten first molten metal is injected into the molten metal The upper surface of the non-solidified liquid phase 71_1L and the mold 80 are separated from each other, and solidification progresses in a direction parallel to the horizontal plane of the molten metal, so that shrinkage holes can easily occur.

The inventor of the present invention has found that when the molten metal 71 is sequentially injected, it is defined by the solid phase 71_1S and the liquid phase 71_1L of the first molten metal held in the mold 80 The second curvature of the solid-liquid interface (S / L) defined by the solid phase (71_2S) and the liquid phase (71_2L) of the second molten metal is smaller than the first curvature of the solid-liquid interface (S / L) The molten metal 71 is divided into the casting space 85 (S / L) so that the third curvature of the solid-liquid interface (S / L) defined by the solid phase 71_3S and the liquid phase 71_3L of the molten metal becomes smaller than the second curvature ), It was confirmed that the generation of shrinkage holes can be suppressed or minimized. Here, the curvature is an inverse number of the radius of curvature, and the radius of curvature means the radius of the arc when a part of the curve (solid-liquid interface) is regarded as an arc.

A casting apparatus 1 for implementing a casting method according to an embodiment of the present invention is a device for injecting a molten metal 71 capable of filling a casting space 85 formed in a mold 80. The casting apparatus 1 has a main chamber 40 capable of receiving the molten metal 71 and a hole 40a formed in the main chamber 40. The casting apparatus 1 is provided so as to protrude from the lower portion of the main chamber 40, A stopper 41 provided so as to open and close a hole 40a formed in the main chamber 40 and a hole 40a formed in the main chamber 40, The upper surface of the molten metal 71 contained in the mold 80 in the non-solidified liquid phase is divided into the mold 80 and the molten metal 71. The molten metal 71 is injected into the casting space 85, And a control unit (90) for controlling the movement of the stopper (41) so that injection can be performed discontinuously at an injection interval set so as to be able to contact without being spaced apart.

The stopper 41 is configured to open and close the hole 40a of the main chamber 40. [ In one embodiment, the stopper 41 may be formed in a bar shape extending through the heater portion as well as the main chamber 40. A pneumatic cylinder 45 is provided on the upper portion of the case 30 to allow the stopper 41 to move up and down. The portion where the stopper 41 contacts the hole 40a of the main chamber 40 may be configured to be tapered to gradually open and close the inner opening of the nozzle 34. [

The control unit 90 can control the movement of the stopper 41 through the pneumatic cylinder 45. [ The control unit 90 may measure the weight and / or the pressure of the molten metal 71 accommodated in the main chamber 40 so that the molten metal 71 having a predetermined capacity is transferred to the main chamber 40, The rising and falling time of the stopper 41 can be determined so that it can flow out to the nozzle 34 through the hole 40a of the stopper 41. [

The casting apparatus 1 including the above-described components can be realized in various forms, and therefore, it is understood that the constitution shown in Fig. 2 is not limited to the technical idea of the present invention, The configuration will be described.

The casting apparatus 1 includes a case 30, a refractory heater 31 provided inside the case 30, a heater heating wire 32 embedded in the inner wall surface of the main chamber side of the heater 31, And further comprises a pipe 51 and a vacuum forming pipe 61.

The case 30 has a cylindrical shape hermetically sealed from the outside. The heater unit 31 installed in the case 30 is made of refractory material to insulate the heat of the molten metal 71 contained therein from being released to the outside to minimize the temperature drop of the molten metal 71. Further, the heater wire 32 embedded in the heater 31 is composed of an electric heater connected to a power source 33. The power supply 33 is formed by a power supply and an electric wire configured to apply an external power to the heater 32. The electric power is supplied from the heater 32 installed in the wall of the main chamber 40 to the main chamber 40, 30 extending outwardly.

The gas injection pipe 51 is provided so as to inject nitrogen or an inert gas into the main chamber 40. The vacuum forming pipe 61 is constituted by a pipe connected to the outside through the case 30 like the gas injection pipe 51 so as to discharge gas and air existing in the main chamber 40 to the outside . The gas tank 50 and the vacuum tank 60 are connected to the gas injection pipe 51 and the vacuum forming pipe 61, respectively. The vacuum tank 60 is constituted by a tank connected to a vacuum forming pipe 61 protruded to the outside of the case 30. The vacuum tank 60 is connected to the vacuum tank 60 by the operation of a vacuum pump coupled to the vacuum tank 60 Pneumatic is formed.

The casting apparatus 1 may have a ladle shape in some cases. The ladle may be raised and lowered by lifting equipment such as a hoist provided on a rail 10 installed on a ceiling of a work site, Or may be moved along. In this case, the case 30 is formed so as to house and enclose the heater unit 31 and the main chamber 40, and a ring member 12 is formed at an upper portion of the case 30, And can move along the rails 10 at the same time. On the other hand, the casting apparatus 1 may not be in the form of the ladle but may be disposed on a main frame fixed on the ground.

In order to facilitate the understanding of the present invention, experimental examples including cases where the above-described technical ideas are applied will be described below. It should be understood, however, that the following examples are for the purpose of promoting understanding of the present invention and are not intended to limit the scope of the present invention.

Table 1 shows experimental examples in which Al-7 wt% Si alloy was implemented by various casting methods. In this experiment, the mold 80 was made of SKD61, and the mold 80 had an inner diameter of 60 mm and a length of 350 mm. The mold 80 was preheated at a temperature of 573 K and then a molten metal injection temperature of 1023 K Respectively.

The total capacity of the molten metal 71 for filling the casting space 85 in Experimental Examples 1 to 7 is commonly 2700 g.

In Experimental Example 1, as a typical casting method, a method of injecting the entire molten metal at one time into the casting space 85 of the mold 80 was applied.

The molten metal 71 to be filled in the casting space 85 of the mold 80 is divided into a predetermined amount and the molten metal is divided into the casting space 85, (85), and injecting a plurality of times in a discontinuous manner at an injection interval.

For example, as shown in FIG. 4, the casting method according to Experimental Example 2 includes a step of injecting a first molten metal having a capacity of 540 g (S101), a step of injecting additional molten metal during the first injection interval of 7.5 seconds (S103); injecting a second molten metal having a capacity of 540 g (S103); maintaining the molten metal (S104) without injecting additional molten metal during the second injection interval of 7.5 seconds; (S106); injecting a fourth molten metal having a capacity of 540 g (S107); (S103) injecting a molten metal of 540 g; (S108) of holding additional molten metal during the fourth injecting interval of seconds (S108) and injecting a fifth molten metal of 540 g capacity (S109).

In Experimental Examples 5 to 7, as the casting method of the above-described variable injection method, the molten metal 71 to be filled in the casting space 85 of the mold 80 is divided, and at least one of the divided molten metals Dividing the molten metal so as to have different capacities from at least one of the divided molten metals, and sequentially injecting the divided molten metal into the casting space 85, Casting method was applied. Particularly, in Experimental Examples 5 to 7, one injection amount, injection time, and injection interval were adjusted according to the solidification rate based on the data obtained through computer simulation.

Further, in Experimental Examples 5 to 7, the molten metal 71 to be filled in the casting space 85 was divided, and at least one of the divided molten metals was divided into at least one of the divided molten metals A casting method in which molten metal of a relatively larger capacity is firstly injected and molten metal of a relatively smaller capacity is injected in succession to be injected later, Respectively.

For example, as shown in FIG. 5, the casting method according to Experimental Example 5 includes a step (S201) of injecting a first molten metal having a capacity of 1200 g, an additional molten metal during a first injection interval of 4 seconds to 10 seconds (S203) of injecting a second molten metal having a capacity of 300 g (S203); maintaining the molten metal (S204) without injecting additional molten metal during a second injection interval of 4 seconds to 10 seconds; (S205) of injecting a third molten metal having a capacity of 300 g, maintaining (S206) without injecting additional molten metal during a third injection interval of 4 seconds to 10 seconds, (S207), a step (S208) of maintaining additional molten metal in the fourth injection interval of 4 seconds to 10 seconds (S208), a step (S209) of injecting a fifth molten metal having a capacity of 300 g During the fifth injection interval of < RTI ID = 0.0 > And a step (S211) of injecting the molten metal of the 6th step (S210) and a 300g capacity for holding without injecting metal.

The effect of pouring cycle, pouring quantity per one cycle, and pouring interval time between pouring cycle on shrinkage cavity is examined in this experiment.

FIG. 6 is a graph illustrating the shape of a shrinkage cavity in a cast material implemented according to an experimental example of the present invention, and FIG. 7 is a diagram illustrating a cross section of cast materials implemented in accordance with an experimental example of the present invention.

Shrinkage may occur in the casting material 100 according to the experimental example of the present invention. The shrinkage hole S may be formed by heat shrinkage from the injection temperature to the liquid temperature, Heat shrinkage to the temperature, phase change from the liquid state to the solid state, and the like. Particularly when the molten metal 71 is solidified, internal defects of the cast material 100 are generated by the shrinkage holes S generated by the density difference between the liquid phase and the solid phase, A method is required.

In the graph shown in Fig. 6, the horizontal axis represents Experimental Example 1 (# 1) to Experimental Example 7 (# 7), and the vertical axis represents the ratio of the shrinkage cavity to the entire cast material. According to Experimental Example 1 (# 1) to Experimental Example 4 (# 4), when the number of injections is subdivided while maintaining the injection amount per injection number, the volume of the syringe S Decreased from 7 vol.% To 1.6 vol.%.

Also, referring to Experimental Example 5 (# 5) to Experimental Example 6 (# 6) to which the interface controlled gradual casting process was applied, the volume of the shrinkage cavity S decreased as the number of injections increased. In Experimental Example 7 (# 7) in which the interface controlled gradual casting process was applied, a degassing process was further performed before the molten metal 71 was injected into the heat-coated metal mold 80. In this case, (S) decreased rapidly to 0.3 vol.%.

7 (a) shows a cross-sectional view observed in the cast material 100 realized by Experimental Example 1 using a conventional casting method, and FIG. 7 (b) shows a casting method of the above- FIG. 7 (c) is a cross-sectional view of the casting member 100 according to Experimental Examples 5 to 7 in which the interface controlled gradual casting process is applied. 7 shows a cross-sectional view observed in the casting material 100 realized by the present invention.

According to the above, in the casting material 100 realized by Experimental Examples 2 to 4, in which the above-described casting method of the dosing method is applied, the casting material 100, which is implemented by Experimental Example 1 using a conventional casting method, And the pores H were hardly found in the cast material 100 realized in Experimental Examples 5 to 7 using the interfacial control type gradual casting process described above.

Particularly, in Experimental Example 7, in which the mold 80 was adhered by thermal coating, and after the degassing treatment and the interfacial control type gradual casting process was applied, the recovery rate was 99.7%, and a healthy microstructure without casting defects was observed throughout the casting material.

Hereinafter, with reference to FIG. 8, the casting recovery rate in the cast material realized according to the experimental example of the present invention and the dendrite arm (DAS) measured in the cast material implemented according to the experimental example of the present invention, 10, measurement results of an X-ray fluorescence spectrometer (XRF) showing the aspect of silicon content in the cast material implemented according to the experimental example of the present invention and the results of measurement according to the experimental example of the present invention Consider the aspect of hardness in the cast material.

Figs. 8 to 11 (a) relate to a cast material realized by a typical static shape casting process in which the entire molten metal is injected at once, and Figs. 8 to 11 (b) 8 to 11 (c) are graphs showing the relationship between the number of injections in the interfacial control type gradual casting process and the number of injections in the interfacial control gradual casting process according to the present invention, The present invention relates to a casting material which is implemented by being carried out.

9 to 11, P1, P2, and P3, which are distances from the surface of the cast material 100 as shown in Fig. 7, are shown as a legend of the graphs shown in Figs. 9 to 11 The items disclosed respectively represent the top, middle, and bottom of the cast material 100, as shown in Fig.

Referring to FIG. 8, an interface-controlled progressive casting (IPC) process is performed instead of a cast material implemented by a conventional static shape casting process in which the entire molten metal is injected at one time It can be seen that the casting recovery is remarkably high in the cast material. Further, it can be confirmed that the casting recovery rate is higher than that in the case where the number of injections in the interface controlled gradual casting process is 10 times that in the case where the number of injections is 5 times.

9, the uniformity of the dendrite arm spacing in the cast material realized by performing the interface controlled gradual casting process rather than the casting material realized by the conventional static casting process in which the entire molten metal is injected at once (uniformity) is higher. Furthermore, it can be seen that the uniformity of the dendritic distance is higher when the number of injections in the interface controlled gradual casting process is 10 times than when the number of injections is 5 times.

10, the uniformity of the silicon concentration distribution in the cast material realized by performing the interfacial control type gradual casting process rather than the cast material realized by the general static casting process in which the entire molten metal is injected at once Higher. Furthermore, it can be seen that the uniformity of the silicon concentration distribution is higher than that in the case where the implantation frequency is 10 times in the interfacial control type gradual casting process.

11, the uniformity of the intensity distribution is more improved in the cast material realized by performing the interface controlled gradual casting process than the cast material realized in the general static casting process in which the entire molten metal is completely injected at one time High. Furthermore, it can be seen that the uniformity of the intensity distribution is higher when the number of injections in the interface controlled gradual casting process is 10 than in the case of 5 injections.

 In the interfacial control type gradual casting process according to an embodiment of the present invention, in the 3-D near-net shape casting of a unit component having a shape, the molten metal injection rate, (S / L) of the molten metal to the final solidification position by controlling the injection interval and the injection temperature, as well as controlling the curvature of the solid-liquid interface and the amount of liquid in the liquid interface front Can be precisely controlled at the same time, thereby suppressing the generation of shrinkage holes in the cast product 100, whereby a cast product having a cast recovery rate of 99% or more can be produced.

The interfacial control type gradual casting process according to an embodiment of the present invention has a higher cast recovery rate than a conventional casting process and does not require a post-process for removing sprue, runner, side riser, gate, top riser, The unit price can be reduced.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (8)

A casting method for casting a molten metal capable of filling a casting space formed in a mold,
Dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the molten metal is discontinuously injected a plurality of times with an injection interval,
Wherein the injection gap is set such that the upper surface of the molten metal contained in the mold while not being in contact with the mold is in contact with the mold while the molten metal is injected a plurality of times. The method according to claim 1,
Dividing the molten metal and sequentially injecting the molten metal into the casting space,
Adjusting at least one of an injection rate, an injection amount, an injection interval, and an injection temperature according to a solidification rate of the molten metal to control a position, a curvature and a liquid fraction of the solid-liquid interface. The method according to claim 1,
Dividing the molten metal and sequentially injecting the molten metal into the casting space,
The molten metal is divided and injected into the casting space sequentially so that the curvature of the solid-liquid interface of the molten metal contained in the metal is sequentially decreased every time the molten metal is sequentially injected, Casting a plurality of times. The method according to claim 1,
Dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the step of discontinuously injecting the molten metal a plurality of times with an injection interval
Dividing the molten metal so that at least one of the divided molten metals differs in capacity from at least one of the other divided molten metals, and sequentially injecting the divided molten metal into the casting space Wherein the step of casting comprises a step of discontinuously injecting a plurality of times with an injection interval. The method according to claim 1,
Dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the step of discontinuously injecting the molten metal a plurality of times with an injection interval
Dividing the molten metal such that at least one of the divided molten metals is divided so as to have a different capacity from at least one other of the divided molten metals, And sequentially injecting the molten metal with a smaller capacity at a later time in order to inject the molten metal at a later time, and injecting the molten metal in a plurality of times at an injection interval discontinuously. The method according to claim 1,
Dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the step of discontinuously injecting the molten metal a plurality of times with an injection interval
Wherein the molten metal is injected into the casting space one after another by injecting the molten metal in a plurality of times at an injection interval. The method according to claim 1,
Wherein the mold comprises an adiabatically coated mold,
And degassing the molten metal before the step of injecting the molten metal. A casting apparatus for injecting molten metal capable of filling a casting space formed in a mold,
A main chamber capable of receiving the molten metal;
A nozzle communicating directly with a hole formed in the main chamber and protruding from a lower portion of the main chamber to provide a flow path for entering and exiting the molten metal;
A stopper installed to open and close a hole formed in the main chamber; And
Wherein the molten metal is divided into a plurality of portions and the molten metal is sequentially injected into the casting space a plurality of times by opening and closing a hole formed in the main chamber, wherein an upper surface of the molten metal contained in the mold is not in contact with the mold A control unit for controlling the movement of the stopper so that injection can be performed discontinuously at a predetermined injection interval;
. ≪ / RTI >

Images