WO2015108217A1

WO2015108217A1 - Casting method and casting device

Info

Publication number: WO2015108217A1
Application number: PCT/KR2014/000524
Authority: WO
Inventors: 김휘준; 이주호; 황규철; 배정찬; 이상목
Original assignee: 한국생산기술연구원
Priority date: 2014-01-17
Filing date: 2014-01-17
Publication date: 2015-07-23
Also published as: DE112014005718B4; DE112014005718T5; JP6246360B2; KR101529234B1; JP2016537202A

Abstract

The present invention relates to a casting method capable of obtaining a high casting yield, minimizing casting defects and eliminating casting post-processing, and a casting device for implementing the same. Provided is: the casting method which is a casting method for injecting a molten metal which is capable of filling a casting space formed in a mold in order to accurately control the position, a curvature and a liquid fraction of a solid-liquid interface, comprising a step for dividing the molten metal and sequentially injecting the molten metal into the casting space, wherein the molten metal is intermittently injected multiple times by spacing the injection intervals, wherein the injection intervals are set such that the top surface of the non-solidified liquid phase of the molten metal received in the mold comes into contact with the mold without being separated while the molten metal is injected multiple times; and the casting device for implementing the same.

Description

Casting method and casting device

The present invention relates to a casting method and a casting apparatus for implementing the same, and more particularly, to a method for casting a healthy unit part with a high casting recovery rate and a minimum casting defect, and a casting apparatus for implementing the same.

In the existing static shape casting process, the molten metal is injected at once, and after the solidification is completed, the casting is taken out. In the existing casting process, in order to guide the shrinkage hole, which is essential in the process of solidifying from liquid to solid due to the density difference between liquid and solid, to a position other than the casting part, a casting design, an inlet, a runner, a runner, etc. A cast product having a shape is manufactured through a post process of separating these from the cast product. According to this, there is a problem in that the casting recovery rate, which is a ratio of the casting to the total casting amount, is about 60%, low, and additional cost and processing time are required according to the post-process, which is the main cause of the increase in the cost of the casting.

Disclosure of Invention The present invention is to solve various problems including the above problems, and an object of the present invention is to provide a casting method and a casting apparatus using the same, which have high casting recovery rate, minimize casting defects, and eliminate post-casting processes. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

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 that can fill the casting space formed in the mold to precisely control the position, curvature and liquid fraction of the solid-liquid interface, the molten metal is divided and injected into the casting space sequentially However, the step of injecting a plurality of discontinuously injecting intervals. The injection interval is set such that the upper surface of the uncondensed liquid phase of the molten metal accommodated in the mold may contact the mold without being spaced apart while injecting the molten metal a plurality of times.

In the casting method, the molten metal is divided and injected into the casting space in sequence, but discontinuously injected a plurality of times with an injection interval, injection rate, injection amount, injection interval and the like depending on the solidification rate of the molten metal It may include the step of adjusting any one or more of the injection temperature. At this time, in the adjusting step, it is possible to suppress the occurrence of shrinkage holes in the casting by controlling any one or more of the amount of liquid phase of the molten metal filled in the casting space, the position and curvature of the solid-liquid interface of the molten metal.

In the casting method, the molten metal is divided and injected into the casting space in sequence, but discontinuously injected a plurality of times at injection intervals, the molten metal contained in the mold each time the molten metal is sequentially injected 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 may be sequentially reduced, but may include discontinuously injecting a plurality of times at injection intervals.

In the casting method, the molten metal is divided and injected into the casting space sequentially, but discontinuously injected a plurality of times at injection intervals, the molten metal is divided, at least one of the divided molten metal And dividing the molten metal so that the capacity is different from at least one of the divided molten metal, and sequentially injecting the divided molten metal into the casting space, respectively, and discontinuously injecting a plurality of injection intervals. Can be.

In the casting method, the molten metal is divided and injected into the casting space sequentially, but discontinuously injected a plurality of times at injection intervals, the molten metal is divided, at least one of the divided molten metal At least one of the divided molten metals is divided so as to have a different capacity from each other, and a relatively larger volume of the molten metal is first injected, and then a relatively smaller volume of the molten metal is sequentially injected, It may include the step of injection discontinuously a plurality of injection intervals.

In the casting method, the molten metal is divided and injected into the casting space sequentially, but discontinuously injected a plurality of times at injection intervals to quantitatively divide the molten metal into the casting space, respectively. Injecting sequentially, it may include the step of injection discontinuously a plurality of injection intervals.

In the casting method, the mold may include an insulation coated mold, and may further include a degassing treatment before the injecting the molten metal.

According to another aspect of the present invention, a casting apparatus is provided. The casting device is a device for implementing the casting method, and is a device for injecting molten metal that can fill the casting space formed in the mold. The casting apparatus may include 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 an access passage for the molten metal, the main chamber. The molten metal is divided and injected into the casting space a plurality of times by opening and closing a stopper provided to open and close the hole formed in the main chamber, and the molten metal contained in the mold is not solidified. It includes a control unit for controlling the movement of the stopper so that the upper surface of the liquid can be discontinuously injected with the injection interval set to be in contact with the mold without being spaced apart.

According to one embodiment of the present invention made as described above, it is possible to provide a casting method and a casting apparatus for implementing the same, the casting recovery rate is high, the casting defect is minimized, and the post-casting process can be omitted. 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 view illustrating a casting apparatus and a mold for implementing a casting method according to embodiments of the present invention.

3 is a view schematically illustrating a casting method according to embodiments of the present invention.

4 is a flow chart illustrating a casting method according to an embodiment of the present invention.

5 is a flow chart illustrating a casting method according to another embodiment of the present invention.

6 is a graph illustrating aspects of shrinkage holes in a cast material implemented according to an experimental example of the present invention.

7 is a view illustrating a cross section of the cast material implemented according to the experimental example of the present invention.

8 is a graph illustrating aspects of the casting recovery rate in the cast material implemented according to the experimental example of the present invention.

9 is a graph showing a measurement result of a dendrite arm spacing (DAS) in a cast material implemented according to an experimental example of the present invention.

10 is a graph illustrating a measurement result of an X-ray fluorescence analyzer (XRF) showing the aspect of the silicon content in the cast material implemented according to the experimental example of the present invention.

11 is a graph illustrating the aspect of hardness in the cast material implemented according to the experimental example of the present invention.

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

The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, and the following examples can be modified in various other forms, and the scope of the present invention is It is not limited to an Example. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of description.

Like numbers refer to like elements throughout. 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" may include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, "comprise" and / or "comprising" specifies the presence of the mentioned shapes, numbers, steps, actions, members, elements and / or groups of these. It is not intended to exclude the presence or the addition of one or more other shapes, numbers, acts, members, 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, embodiments of the inventive concept should not be construed as limited to the specific shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing.

1 is a flow chart illustrating a casting method according to embodiments of the present invention, Figure 2 is a view illustrating a casting apparatus and a mold for implementing a casting method according to embodiments of the present invention, Figure 3 A diagram schematically illustrating a casting method according to embodiments of the present invention.

1 and 2, a casting method according to an embodiment of the present invention is a casting method for injecting a molten metal 71 capable of filling a casting space 85 formed in a mold 80. Splitting the molten metal 71 and injecting the molten metal 71 sequentially into the casting space 85, the step of injecting a plurality of discontinuous injection intervals.

In the casting method according to an embodiment of the present invention, for example, injecting a first molten metal, at least a portion of the first molten metal is solidified without injecting additional molten metal during the first injection interval. Step, injecting the secondary molten metal, solidifying at least a portion of the secondary molten metal without injecting additional molten metal during the secondary injection interval, may be performed in a similar manner. To perform the step of finally injecting the (N-1) th molten metal, without injecting additional molten metal during the (N-1) th injection interval. By casting at least a portion and injecting the N-th molten metal, the casting space 85 of the mold 80 may be filled to form a cast product. Wherein N is a positive integer of 2 or greater.

The first molten metal to the Nth molten metal may have the same capacity. In this case, in the casting method according to an embodiment of the present invention, a molten metal 71 to be filled in the casting space 85 is quantitatively divided, and the molten metal is sequentially injected into each of the casting space 85, but is injected. It may include the step of injecting a plurality of discontinuously at intervals, such a casting method is referred to as a casting method of the metering injection method below.

Meanwhile, at least one of the first molten metal and the Nth molten metal may have a different capacity from at least one of the other. In this case, the casting method according to an embodiment of the present invention divides the molten metal 71 to be filled in the casting space 85, wherein at least one of the divided molten metals is at least one of the divided molten metals. It is divided into one and the capacity different from each other, and each of the molten metal is sequentially injected into the casting space (85), it may include the step of injecting a plurality of discontinuously injected injection intervals, such a casting method Hereinafter 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 has a capacity equal to at least one of the divided molten metals. The casting method is divided into different parts, in which molten metal of a relatively larger capacity is first injected, and then molten metal of a relatively smaller capacity is sequentially injected so as to be injected later. The generation of shrinkage pores can be suppressed more effectively.

Casting method according to an embodiment of the present invention, the injection rate, injection amount, injection interval and injection temperature of the injection into the mold 80 in accordance with the solidification rate of the molten metal 71 to suppress the generation of shrinkage holes in the casting Controlling any one or more may include controlling any one or more of the amount of liquid phase of the molten metal 71 filled in the casting space 85, the position and curvature of the solid-liquid interface of the molten metal 71. In particular, such a casting method is hereinafter referred to as an interface-controlled progressive casting process (IPC).

1 to 3, in the casting method according to an embodiment of the present invention, the molten metal 71 is divided and sequentially injected into the casting space 85, but a plurality of injections are discontinuously injected at intervals of injection intervals. Wherein, the injection interval, while the molten metal 71 is injected a plurality of times, the upper surface of the uncondensed liquid phase of the molten metal 71 accommodated in the mold 80 is not spaced apart from the mold 80 Can be set to encounter.

In addition, in the casting method according to an embodiment of the present invention, whenever the molten metal 71 is sequentially injected, the curvature of the solid-liquid interface S / L of the molten metal 71 accommodated in the mold 80 is sequentially In order to be smaller, the molten metal 71 may be divided and injected into the casting space 85 sequentially, but may include discontinuously injecting a plurality of times at injection intervals.

For example, referring to FIG. 3A, a primary molten metal having a predetermined capacity is injected into a casting space of a mold 80 and at least a portion of the primary molten metal during a first injection interval. Can remain solidified. In this case, at the time when the first injection interval passes, the primary molten metal accommodated in the mold 80 may be divided into a solidified solid phase 71_1S and an unsolidified liquid phase 71_1L, and a solid phase 71_1S. ) And the liquid-liquid interface S / L of the liquid phase 71_1L may have a first curvature.

Referring to FIG. 3B, after the first injection interval, a second molten metal having a predetermined capacity is injected into the casting space of the mold 80, and subsequently, the second injection interval is applied during the second injection interval. At least a portion of the secondary molten metal can be kept solidified. In this case, at the time when the second injection interval passes, the primary molten metal contained in the mold 80 is present as a solid phase (71_1S) in which all or a part is solidified, and the secondary molten metal is in the solidified solid phase. The liquid crystal surface S / L of the liquid phase 71_2S and the liquid phase 71_2L may have a second curvature.

Referring to FIG. 3C, after the second injection interval, a third molten metal having a predetermined capacity is injected into the casting space of the mold 80, and subsequently, the third injection interval is injected during the third injection interval. At least a portion of the tertiary molten metal can be kept solidified. In this case, at the time when the third injection interval passes, the secondary molten metal contained in the mold 80 is present as a solid phase 71_2S in which all or a part is solidified, and the third molten metal is in the solidified solid phase. 71_3S and the still uncondensed liquid 71_3L, and the solid-liquid interface S / L of the solid phase 71_3S and the liquid phase 71_3L may have a third curvature.

The inventors of the present invention allow the upper surface of the uncondensed liquid phase of the molten metal 71 accommodated in the mold 80 to be in contact with the mold 80 without being spaced apart while injecting the molten metal 71 a plurality of times (Fig. In the case of setting the injection interval, it was confirmed that the occurrence of shrinkage holes can be suppressed or minimized.

For example, the first injection interval interposed between the step of injecting the primary molten metal and the step of injecting the secondary molten metal is uncoagulated of the primary molten metal contained in the mold 80. The upper surface of the liquid phase 71_1L may be set to be in contact with the mold 80 without being spaced apart. If the secondary molten metal is injected at the time when the primary injection interval is exceeded, solidification of the unsolidified liquid phase 71_1L of the primary molten metal is performed before the secondary molten metal is injected. Further progresses, while the upper surface and the mold 80 of the non-coagulated liquid (71_1L) is spaced apart as the solidification proceeds in parallel with the horizontal surface of the molten metal, shrinkage holes can easily occur.

In addition, the inventor of the present invention is defined by the solid phase 71_1S and the liquid phase 71_1L of the primary molten metal contained in the mold 80 each time the molten metal 71 is sequentially injected. 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, and is the third order. The molten metal 71 is divided into a casting space 85 such 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 is smaller than the second curvature. When sequentially injected into), it was confirmed that the occurrence of shrinkage pores can be suppressed or minimized. Here, the curvature is the inverse of the radius of curvature, the radius of curvature refers to the radius of the arc when a portion of the curve (solid-liquid interface) is considered as an arc.

On the other hand, the casting apparatus 1 implementing the casting method according to an embodiment of the present invention is a device for injecting a molten metal 71 that can fill the casting space 85 formed in the mold (80). The casting apparatus 1 is in direct communication with the main chamber 40 capable of accommodating the molten metal 71 and the hole 40a formed in the main chamber 40, and is protruded from the lower portion of the main chamber 40 to be melted. A nozzle 34 that provides an access flow path for the metal 71, a stopper 41 installed to open and close the hole 40a formed in the main chamber 40, and a hole 40a formed in the main chamber 40. The molten metal 71 is divided and injected into the casting space 85 in a plurality of times by opening and closing the molten metal 71, and the upper surface of the uncondensed liquid phase of the molten metal 71 accommodated in the mold 80 is separated from the mold 80. It includes a control unit 90 for controlling the movement of the stopper 41 so as to discontinuously inject the injection interval set so as 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 have a rod shape extending through the heater unit as well as the outside of the case as well as the main chamber 40. The pneumatic cylinder 45 is installed on the case 30 to enable the stopper 41 to move up and down. The portion where the stopper 41 is in contact with the hole 40a of the main chamber 40 may be configured to taper to gradually open and close the inner opening of the nozzle 34.

The controller 90 may control the movement of the stopper 41 through the pneumatic cylinder 45. Further, the controller 90 measures the weight and / or pressure of the molten metal 71 accommodated in the main chamber 40, for example, so that the molten metal 71 having a predetermined capacity is supplied to the main chamber 40. The rise and fall time of the stopper 41 can be determined so as to flow out to the nozzle 34 through the hole 40a of the.

Since the casting apparatus 1 including the above-described components may be implemented in various forms, the rest of the casting apparatus 1 may be understood while not being limited to the technical idea of the present invention by the configuration shown in FIG. 2. The configuration will be described.

The casting device 1 includes a case 30, a refractory heater unit 31 installed inside the case 30, a heater heating wire 32 embedded in an inner wall surface of the main chamber side of the heater unit 31, and a gas injection unit. The pipe 51 and the vacuum forming pipe 61 may be further included.

The case 30 has a cylindrical shape sealed from the outside. The heater unit 31 installed in the case 30 is made of refractory to insulate that heat of the molten metal 71 accommodated therein is released to the outside, thereby minimizing the temperature drop of the molten metal 71. In addition, the heater heating wire 32 embedded in the heater 31 is composed of a heat transfer heater to which the power source 33 is connected. The power source 33 is formed of a power source and an electric line configured to apply an external power source to the heater 32, and the electric line is formed by the main chamber 40 and the case (to be described later) in the heater 32 installed inside the wall of the main chamber 40. 30 may extend through the outside.

The gas injection pipe 51 is provided to inject nitrogen or an inert gas into the main chamber 40. The vacuum forming pipe 61 is composed of a pipe connected to the outside through the case 30 in the same manner as the gas injection pipe 51 so as to discharge the gas and air existing inside 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 composed of a tank connected to the vacuum forming pipe 61 protruding to the outside of the case 30, the vacuum tank 60 by the operation of the vacuum pump coupled to the vacuum tank 60 Pneumatic pressure is formed.

The casting device 1 may have the form of a ladle, in some cases, the ladle being lifted up and down by a lifting equipment such as a hoist installed on the rail 10 installed on the ceiling of the workshop and simultaneously lifting the rail 10. May be moved accordingly. In this case, the case 30 is formed to accommodate the heater 31 and the main chamber 40 to be wrapped therein, the upper ring member 12 is formed on the rail 10 by using a separate wire, etc. It is lifted and lowered by the lifting equipment installed at the same time can move along the rail (10). On the other hand, the casting device 1 may be disposed on the main frame fixed to the ground, not in the form of the ladle.

Hereinafter, experimental examples including the case where the above-described technical spirit is applied to help the understanding of the present invention will be described. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited to the following experimental examples.

Table 1 shows experimental examples of implementing the Al-7 wt% Si alloy by various casting methods. In the present test examples, the mold 80 was made of SKD61 material, and the size of the mold 80 was 60 mm in inner diameter and 350 mm in length, and after preheating the mold 80 at a temperature of 573 K, a molten metal injection temperature of 1023 K was obtained. It was performed while maintaining.

Table 1

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

In Experimental Example 1, as a conventional casting method, a method of injecting all of the molten metal into the casting space 85 of the mold 80 at once was applied.

Experimental Examples 2 to 4 are the above-described quantitative injection method of casting, wherein the molten metal 71 to be filled in the casting space 85 of the mold 80 is quantitatively divided and the molten metal divided into casting spaces, respectively. Injected sequentially to (85), but the casting method consisting of the step of injecting a plurality of discontinuously with an injection interval was applied.

For example, as shown in Figure 4, the casting method according to Experimental Example 2 is a step of injecting the first molten metal of 540g capacity (S101), without injecting additional molten metal during the first injection interval of 7.5 seconds Maintaining step (S102), injecting the second molten metal of 540g capacity (S103), maintaining without injecting additional molten metal during the second injection interval of 7.5 seconds (S104), the third of the 540g capacity Injecting the primary molten metal (S105), maintaining without injecting additional molten metal during the third injection interval of 7.5 seconds (S106), injecting a fourth molten metal of 540g capacity (S107), 7.5 Maintaining without injecting additional molten metal during the fourth injection interval of seconds (S108) and injecting a fifth molten metal of 540g capacity (S109).

Experimental Example 5 to Experimental Example 7 is a casting method of the above-described variable injection method, wherein 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 is divided. Is divided so as to have a different capacity from at least one other of the divided molten metal, and sequentially injecting the divided molten metal into the casting space 85, respectively, discontinuously injecting a plurality of injection intervals. A casting method consisting of was applied. Particularly, in Experimental Examples 5 to 7, the injection amount, injection time, injection interval, and the like 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 is divided, and at least one of the divided molten metals has a capacity equal to at least one of the divided molten metals. It is divided into different parts, and a molten metal of a relatively larger capacity is first injected, and then a molten metal of a relatively smaller capacity is sequentially injected so as to be injected later. It was.

For example, as shown in Figure 5, the casting method according to Experimental Example 5 is a step of injecting the first molten metal of 1200g capacity (S201), during the first injection interval of 4 seconds to 10 seconds additional molten metal Maintaining without injecting (S202), injecting a second molten metal of 300g capacity (S203), maintaining without injecting additional molten metal during the second injection interval of 4 seconds to 10 seconds (S204) Injecting the third molten metal of 300g capacity (S205), maintaining without injecting additional molten metal during the third injection interval of 4 seconds to 10 seconds (S206), the fourth molten metal of 300g capacity Injecting step (S207), the step of maintaining without injecting additional molten metal during the fourth injection interval of 4 seconds to 10 seconds (S208), injecting the fifth molten metal of 300g capacity (S209), 4 Additional use during the fifth infusion interval of seconds to 10 seconds And a step (S211) of injecting the molten metal of the 6th step (S210) and a 300g capacity for holding without injecting metal.

In this experimental example, the effect of the pouring cycle (pouring cycle, pouring quantity per one cycle, pouring interval (pouring interval time between pouring cycle) on the shrinkage cavity will be examined.

6 is a graph illustrating an aspect of the shrinkage hole in the cast material implemented according to the experimental example of the present invention, Figure 7 is a diagram illustrating a cross section of the cast material implemented according to the experimental example of the present invention.

Looking at the cross section of the cast material 100 implemented according to the experimental example of the present invention can be seen that the shrinkage hole (S; Shrinkage), the shrinkage hole (S) is a heat shrink from the injection temperature to the liquid temperature, solid state at the liquid temperature It is caused by heat shrinkage to temperature, phase change from liquid state to solid state. In particular, since the internal defects of the casting material 100 are generated by the shrinkage hole S generated by the difference in density between the liquid phase and the solid phase during solidification of the molten metal 71, casting which suppresses the occurrence of such shrinkage holes S is performed. 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 shrinkage holes with respect to the entire cast material. According to this, referring to Experimental Example 1 (# 1) to Experimental Example 4 (# 4), in the case of subdividing the number of injections while maintaining a constant injection amount per injection number, the volume of the shrinkage hole S increases as the number of injections increases. Decreased from 7 vol.% To 1.6 vol.%.

In addition, 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 hole S decreased as the number of injections increased. In addition, in Experimental Example 7 (# 7) to which the interfacial controlled gradual casting process was applied, the degassing treatment was further performed prior to the step of injecting the molten metal 71 into the insulation-coated mold 80. In this case, the shrinkage hole The volume of (S) drastically decreased to 0.3 vol.%.

Figure 7 (a) is a cross-sectional view observed in the casting material 100 implemented by Experimental Example 1 applying the conventional casting method, Figure 7 (b) is the casting method of the above-described metered injection method Figure 7 shows a cross-sectional view observed in the cast material 100 implemented by Experimental Example 2 to Experimental Example 4, Figure 7 (c) is the Experimental Example 5 to Experimental Example to which the above-described interface controlled progressive casting process is applied. Figure 7 shows the cross-sectional view observed in the cast material 100 implemented by.

According to this, in the casting material 100 implemented by Experimental Example 2 to Experimental Example 4 applying the casting method of the above-described quantitative injection method observed than the casting material 100 implemented by Experimental Example 1 applying the conventional casting method The pores (H) was significantly reduced, it was confirmed that the pores (H) is hardly found in the cast material 100 implemented by Experimental Example 5 to Experimental Example 7 applying the above-described interface-controlled progressive casting process.

In particular, in Experimental Example 7 in which the die 80 was adiabatic coated and degassed, and then subjected to an interfacial controlled gradual casting process, the coarse yield was 99.7%, and the entire microstructure without casting defects was observed.

Hereinafter, the casting recovery rate in the cast material implemented according to the experimental example of the present invention with reference to FIG. 8, and the dendritic distance (DAS) measured in the cast material implemented according to the experimental example of the present invention with reference to FIG. 9. Spacing), the measurement results of the X-ray fluorescence analyzer (XRF) showing the aspect of the silicon content in the cast material implemented according to the experimental example of the present invention with reference to FIG. 10 and implemented according to the experimental example of the present invention with reference to FIG. The hardness of the castings.

8 to 11 (a) relates to a casting material implemented by a conventional static shape casting process in which all of the molten metal is injected all at once, and FIGS. 8 to 11 (b) It relates to a cast material implemented by performing the injection frequency 5 times in the interface controlled gradual casting process according to the present invention, Figures 8 to 11 (c) is 10 times the injection frequency in the interface controlled gradual casting process according to the present invention It relates to a casting material implemented by performing.

Meanwhile, the horizontal axis disclosed in FIGS. 9 to 11 represents P 1, P 2, and P 3, which are distances from the surface of the cast material 100, as shown in FIG. 7, and as a legend of the graph shown in FIGS. 9 to 11. Each disclosed item represents a 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 rather than a casting material implemented by a conventional static shape casting process in which all of the molten metal is injected at once. It can be seen that the casting recovery (Recovery) in the implemented cast material is significantly high. Furthermore, it can be seen that the number of injection times of the interface controlled gradual casting process is higher than that of the case of five injection times.

9, the uniformity of the dendrite arm spacing in the cast material implemented by performing the interface controlled gradual casting process rather than the casting material implemented by the conventional static casting process injecting all of the molten metal all at once You can see that (uniformity) is higher. Furthermore, it can be seen that the uniformity of the dendritic distance is higher when the injection frequency of the interface controlled gradual casting process is 10 times than when the injection frequency is 5 times.

Referring to FIG. 10, the uniformity of the silicon concentration distribution in the cast material implemented by performing the interface controlled gradual casting process rather than the cast material implemented by the conventional static casting process injecting all of the molten metal all at once You can see that it is higher. Furthermore, it can be seen that the uniformity of the silicon concentration distribution is higher when the injection frequency of the interface controlled gradual casting process is 10 times than when the injection frequency is 5 times.

Referring to FIG. 11, the uniformity of the strength distribution is higher in the cast material implemented by performing the interface controlled gradual casting process than the cast material implemented by the conventional static casting process in which all of the molten metal is injected all at once. You can see the high. Furthermore, it can be seen that the uniformity of the intensity distribution is higher when the injection frequency of the interface controlled gradual casting process is 10 times than when the injection frequency is 5 times.

In the interface controlled gradual casting process according to an embodiment of the present invention, in the 3-D near-net shape casting of a unit part having a shape, an injection rate, an injection amount, By controlling the injection interval and injection temperature, the solid liquid interface (S / L) of molten metal is controlled to be moved to the final solidification position, and the curvature of the solid-liquid interface, the amount of liquid in front of the solid-liquid interface, etc. By controlling precisely at the same time to suppress the occurrence of shrinkage holes in the cast product 100 is a process that can produce a cast product with a recovery rate of 99% or more.

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

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims

A casting method for injecting molten metal capable of filling a casting space formed in a mold,

Splitting the molten metal and sequentially injecting the molten metal into the casting space, and discontinuously injecting a plurality of times at intervals of injection;

The injection interval is set so that the upper surface of the uncondensed liquid phase of the molten metal accommodated in the mold can contact the mold without being spaced apart during the injection of the molten metal a plurality of times.
The method of claim 1,

Splitting the molten metal and injecting the molten metal sequentially into the casting space, the step of injecting a plurality of discontinuously injecting intervals,

In order to control the position, curvature and the liquid fraction of the solid-liquid interface, the method comprising the step of adjusting any one or more of the injection speed, injection amount, injection interval and injection temperature according to the solidification rate of the molten metal.
The method of claim 1,

Splitting the molten metal and injecting the molten metal sequentially into the casting space, the step of injecting a plurality of discontinuously injecting intervals,

Whenever the molten metal is sequentially injected, 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 mold is sequentially decreased, but the injection interval is discontinuously. Injecting a plurality of times, the casting method.
The method of claim 1,

Splitting the molten metal and injecting the molten metal sequentially into the casting space, the step of injecting a plurality of discontinuous injection intervals

The molten metal is divided, wherein 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 the divided molten metals are sequentially injected into the casting space, respectively. However, the injection method comprising the step of injection discontinuously a plurality of injection intervals.
The method of claim 1,

Splitting the molten metal and injecting the molten metal sequentially into the casting space, the step of injecting a plurality of discontinuous injection intervals

Splitting the molten metal, wherein 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 a relatively larger volume of the molten metal is first injected and then And sequentially injecting molten metal of a smaller capacity into later injections, but discontinuously injecting a plurality of times at injection intervals.
The method of claim 1,

Splitting the molten metal and injecting the molten metal sequentially into the casting space, the step of injecting a plurality of discontinuous injection intervals

Injecting the molten metal divided by the quantitative splitting of the molten metal sequentially into the casting space, respectively, the injection method comprising the step of discontinuously injecting a plurality of injection intervals.
The method of claim 1,

The mold includes a heat-insulated mold,

Further comprising the step of degassing prior to the step of injecting the molten metal.
A casting apparatus for injecting molten metal that can fill the casting space formed in the mold,

A main chamber capable of receiving the molten metal;

A nozzle in direct communication with a hole formed in the main chamber and protruding from a lower portion of the main chamber to provide an access passage for the molten metal;

A stopper installed to open and close a hole formed in the main chamber; And

The molten metal is divided and injected into the casting space in a plurality of times by opening and closing a hole formed in the main chamber, and the upper surface of the uncondensed liquid phase of the molten metal accommodated in the mold may be contacted without being spaced apart from the mold. A control unit for controlling the movement of the stopper so as to discontinuously inject at an injection interval set to allow discontinuous injection;

Including, casting apparatus.