KR102207623B1 - Ultrasonic casting system and manufacturing method of casting alloy using the same - Google Patents

Abstract

According to an aspect of the present invention, there is provided an ultrasonic treatment casting system. The ultrasonic treatment casting system includes a melting furnace capable of melting metal; An ultrasonic treatment device capable of ultrasonicating the molten metal melted by the melting furnace; A supercooling unit capable of subcooling the sonicated molten metal; And a mold into which the supercooled molten metal is injected.

Description

Ultrasonic casting system and manufacturing method of casting alloy using the same {Ultrasonic casting system and manufacturing method of casting alloy using the same}

The present invention relates to an ultrasonic casting system capable of realizing the microstructure of the main alloy by using ultrasonic treatment and a method of manufacturing the main alloy using the same.

In the case of the main alloy, it is known that mechanical properties such as strength and elongation can be improved by miniaturizing the structure. Therefore, various treatments are performed on the molten metal during the casting step to refine the structure of the main alloy.

For example, an additive for micronization may be added to the molten metal to refine the size of the supernormal phase or process phase formed during the solidification process. For example, in an over-eutectic Al-Si-based main alloy that implements an aluminum alloy containing 12.6% by weight or more of silicon by a casting method, a large amount of eutectic Si as well as primary Si is present. Various additives are added to refine the silicon. However, the first additive added to refine the primary silicon and the second additive added to refine the eutectic silicon may cause a chemical reaction with each other, thereby reducing the micronization effect by half. In addition, in order to prevent such a chemical reaction, a double dissolution method has been proposed, but at least two or more dissolution and casting processes are required, resulting in an increase in manufacturing cost.

Another example for the refinement of the main alloy is the ultrasonic treatment of the molten metal. It has been reported that a number of cases in which the microstructure of the main alloy is realized by casting the molten metal directly after ultrasonic treatment is performed. However, depending on the alloy system to be treated, there are cases where the effect of the ultrasonic treatment does not appear unexpectedly, and the cause of this has not yet been clearly identified.

Accordingly, the present invention is to solve a number of problems, including the above problems, and an ultrasonic treatment casting system capable of reliably securing the microstructure of a microstructure when casting an ultrasonically treated molten metal, and a method for manufacturing a cast iron using the same It is for the purpose of providing. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

According to one aspect of the present invention for solving the above problem, an ultrasonic treatment casting system is provided.

The ultrasonic treatment casting system includes a melting furnace capable of melting metal; An ultrasonic treatment device capable of ultrasonicating the molten metal melted by the melting furnace; A supercooling unit capable of subcooling the sonicated molten metal; And a mold into which the supercooled molten metal is injected.

In the ultrasonic casting system, the subcooling unit may be disposed in a path through which the molten metal flows to be introduced into the mold.

In the ultrasonic treatment casting system, a heat insulation part may be formed between the supercooled part and the mold.

In the ultrasonic treatment casting system, a part of the supercooled part may be combined with one surface of the heat insulating part, and a part of the mold may be combined with the other surface of the heat insulating part.

In the ultrasonic treatment casting system, the heat insulating part may include at least one of calcium silicate, rock wool, glass fiber, and ceramic fiber.

In the ultrasonic treatment casting system, the subcooling unit may be configured to radiate thermal energy of the molten metal to the outside by contacting the molten metal.

In the ultrasonic treatment casting system, the subcooling unit may be disposed above the injection hole of the mold, and may be in the shape of a plate inclined at a predetermined angle so that the molten metal can flow to the injection hole of the mold.

In the ultrasonic treatment casting system, a molten metal transfer path through which the molten metal can flow may be formed on one surface of the plate.

In the ultrasonic treatment casting system, the supercooling unit may be disposed to perform a supercooling treatment before the molten metal is injected into the mold by being coupled to an upper portion of the injection port of the mold.

In the ultrasonic treatment casting system, the subcooling unit comprises: a main body; And a molten metal transfer path formed inside the main body and including an inclined surface inclined to allow the molten metal to flow downward and an outlet through which the molten metal is discharged into the mold.

In the ultrasonic treatment casting system, the body may include a seating surface that is seated on one surface of the injection port of the mold, and a heat insulating part is formed between the upper surface of the injection port of the mold and the seating surface of the body. .

In the ultrasonic treatment casting system, a flow path through which a cooling medium can flow may be further included in the body.

In the ultrasonic treatment casting system, further comprising a tilt-type ultrasonic treatment furnace, wherein the subcooling part is in the form of a plate, and one end is connected to the inlet of the ultrasonic treatment furnace, and the other end is connected to the upper surface where the injection hole of the mold is formed. I can.

In the ultrasonic treatment casting system, a heat insulation part may be formed in at least one of the supercooling treatment part and the connection part of the ultrasonic treatment furnace, and the supercooling treatment part and the connection part of the mold.

In the ultrasonic treatment casting system, the subcooled part may be made of copper or a copper alloy.

According to another aspect of the present invention for solving the above problem, there is provided a method of manufacturing a main alloy using ultrasonic treatment.

The manufacturing method of the main alloy using the ultrasonic treatment comprises the steps of ultrasonicating the molten metal in which the metal is dissolved; Subcooling the sonicated molten metal; And injecting the supercooled molten metal into a mold and solidifying it.

In the method of manufacturing the main alloy using the ultrasonic treatment, the subcooling may be performed in a path through which the molten metal flows to be introduced into the mold.

In the method of manufacturing the main alloy using the ultrasonic treatment, the subcooling may include direct contact with the subcooling treatment unit disposed in the path to radiate thermal energy of the molten metal to the outside.

In the method of manufacturing the main alloy using the ultrasonic treatment, the subcooling may include cooling the molten metal while flowing along an inclined surface inclined toward the injection port of the mold at a predetermined angle.

In the method for manufacturing the main alloy using the ultrasonic treatment, the metal may include an aluminum alloy.

According to another aspect of the present invention for solving the above problem, a mold assembly for casting an ultrasonically treated molten metal is provided.

The mold assembly for manufacturing the main alloy is a mold into which the ultrasonically treated molten metal is injected; And a subcooling unit disposed above the injection hole of the mold and contacting the molten metal to radiate thermal energy of the molten metal to the outside.

In the mold assembly for manufacturing the main alloy, a heat insulating portion may be formed between the supercooled portion and the mold. For example, a part of the subcooling treatment part may be combined with one surface of the heat insulating part, and a part of the mold may be combined with the other surface of the heat insulating part.

In the mold assembly for manufacturing the main alloy, the heat insulating portion may include at least one of calcium silicate, rock wool, glass fiber, and ceramic fiber.

In the mold assembly for manufacturing the main alloy, the subcooling unit, the main body; And a molten metal transfer path formed inside the main body and including an inclined surface inclined to allow the molten metal to flow downward and an outlet through which the molten metal is discharged into the mold.

In the mold assembly for manufacturing the main alloy, the subcooled part may be made of copper or a copper alloy.

In the case of the ultrasonic treatment casting system of the present invention made as described above, the supercooling of the molten metal significantly increases the effect of the ultrasonic treatment compared to the prior art, and thus can greatly contribute to the microstructure of the main alloy. Of course, the scope of the present invention is not limited by these effects.

1 shows a change in the size of a nucleating agent particle according to the application of ultrasonic waves to a molten metal and a subcooling effect accordingly.
2 to 5 are diagrams schematically illustrating an ultrasonic casting system and a casting method according to the embodiments of the present invention.
6 is a result of observing the microstructure of the alloy samples corresponding to Comparative Examples 1a to 1c and Experimental Example 1 in a cast state.
7 is a graph illustrating the average size and size distribution of primary Si in the alloy samples corresponding to Comparative Examples 1a to 1c and Experimental Example 1. FIG.
8 shows changes in tensile strength (UTS) and elongation (Elongation) after T6 heat treatment of the alloy samples corresponding to Comparative Examples 1a to 1c and Experimental Example 1.
9 is a result of observing the microstructure of the alloy samples corresponding to Comparative Examples 2a to 2c and Experimental Example 2 in a cast state.
10 and 11 are results showing the grain size and size distribution of the alloy samples corresponding to Comparative Examples 2a to 2c and Experimental Example 2.
12 is a measurement of changes in tensile strength, yield strength (YS), and elongation of the alloy samples corresponding to Comparative Examples 2a to 2c and Experimental Example 2 after casting.
13 is a result of observing the microstructure of the alloy samples corresponding to Comparative Examples 3a to 3c and Experimental Example 3 in a cast state.
14 and 15 are results showing the grain size and size distribution of the alloy samples corresponding to Comparative Examples 3a to 3c and Experimental Example 3.
16 is a result of measuring changes in tensile strength, yield strength, and elongation after casting of the alloy samples corresponding to Comparative Examples 3a to 3c and Experimental Example 3.

Hereinafter, various 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 completely describe the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, and the scope of the present invention is as follows. It is not limited to the examples. Rather, these embodiments are provided to make the present disclosure more faithful and complete, and to completely convey the spirit of the present invention to those skilled in the art.

1 is a graph for explaining a change in the size of a nucleating agent and a subcooling effect according to the application of ultrasonic waves according to an embodiment of the present invention.

In general, when ultrasonic waves are applied to the molten metal, cavitation occurs inside the molten metal. At this time, non-uniform nucleation is induced by cavitation, so that the super-normal phase (mainly crystal grains, primary Si, primary intermetallic compounds, etc.) at the time of solidification becomes fine. Several hypotheses have been proposed regarding the mechanism of heterogeneous nucleation by cavitation, but one of the most supported hypotheses is the wetting mechanism of non-wetting particles. Various kinds of non-metallic particles exist in trace amounts in the molten metal. The non-metallic particles include, for example, oxide-based fine impurity particles and those intentionally added as a refiner. The non-metallic particles can potentially become nucleants of coagulation nuclei that can contribute to actual coagulation during a phase transformation in which the liquid molten metal is coagulated. However, most of these impurity particles show low wettability in the molten metal due to poor wettability. Therefore, it cannot play a role as a non-uniform nucleus that contributes to the solidification of the actual liquid in such a bath, and eventually, it cannot contribute to the microstructure of the main cooperative gold. On the other hand, when the ultrasonic treatment is performed, since the above-described impurity particles are wetted to serve as a nucleating agent, it is possible to contribute to miniaturization.

However, in some cases, even after the ultrasonic treatment is performed, the micronization effect may not appear, or may appear insignificant, unexpectedly. This is interpreted as because the ultrasonic effect did not appear due to other reasons that cannot be explained only by the wetting effect of the ultrasonic treatment.

The present inventors analyzed this phenomenon in terms of the theory of non-uniform nucleation and growth occurring during the process of solidification from liquid to solid, and as a result of this analysis, in order to maximize the effect of ultrasonic treatment, supercooling treatment during the process of tapping the molten metal into a mold. Found that may be needed.

That is, as shown in (a) of FIG. 1, the nucleating agents mainly composed of non-metal particles in the molten metal are more than when ultrasonic waves are not applied (No UST) by the ultrasonic energy applied during ultrasonic treatment (UST). It can be broken into smaller sizes, resulting in fine particles. When coagulation occurs due to heterogeneous nucleation in the liquid phase, the size of the nucleating agent must be greater than or equal to the critical value in order to overcome the barrier energy of the transition from the liquid phase to the solid phase. If the size of the nucleating agent is smaller than the critical size, the nucleating agent cannot play a role as a coagulation nucleus that grows a liquid phase and changes it into a solidified phase. This means that nucleating agents smaller than the critical size will not substantially contribute to the solidification of the liquid phase.

In the process of sonicating the molten metal, when the nucleating agent in the molten metal is split by ultrasonic waves and the particle size decreases than the critical size for coagulation nuclei, the number of nucleating agents that can substantially contribute to coagulation is rather reduced. Eventually, it will not be able to contribute to the miniaturization of the main cooperative funds.

The present inventors recognize the problem of such ultrasonic treatment, and as a result of continuing research to solve this problem, the effect of ultrasonic treatment will be maximized if the molten metal is supercooled during the process of tapping into a mold after ultrasonic treatment. I found that I can.

Some degree of subcooling is required in order to solidify due to heterogeneous nucleation in the liquid phase. Here, the subcooling is the degree of cooling below the melting point (ΔT ₁ , ΔT ₂ ). Referring to (b) of FIG. 1, when appropriate subcooling occurs in the molten metal, the number of activated nucleating agents (that is, the number of nucleating agents that can actually contribute to coagulation, No. of nucleation events) can be maximized. have. Referring to FIG. 1(b), the optimal subcooling before ultrasonic treatment was △T _1, but as the size of impurities became finer due to the ultrasonic treatment, the number of activated nucleating agents decreased in the same subcooling △T ₁ And the number of inactivated nucleating agents increases.

In order to activate the deactivated nucleating agent, it is necessary to further increase the degree of subcooling as shown in (b) of FIG. 1. That is, as the subcooling increases, the critical size of the coagulation nuclei tends to decrease, which means that as the subcooling increases, the size of the nucleating agent that can contribute as a nucleus for solidifying the liquid phase becomes smaller. Therefore, as shown in Fig. 1(b), when the size of the nucleating agent in the molten metal is further refined by ultrasonic treatment, if the supercooling degree of the sonicated molten metal is increased (△T ₂ ), the refined nucleating agent As it is activated as a coagulation nucleus, the number of nucleating agents that can actually contribute to coagulation is greatly increased. As the number of solidification nuclei in the molten metal increases, the cast alloy can implement a remarkably fine metal structure.

Based on this metal phase transformation theory, in the present invention, after applying ultrasonic waves, a subcooling effect is added to obtain a larger structure refinement effect.

The ultrasonic treatment casting system according to an embodiment of the present invention can actually implement the theory proposed by the present inventors, a melting furnace capable of dissolving metal, an ultrasonic treatment capable of performing ultrasonic treatment on the molten metal dissolved in the melting furnace. An apparatus, a mold into which the sonicated molten metal is injected, and a supercooling unit capable of supercooling the molten metal during a process of introducing the sonicated molten metal into the mold.

The subcooling unit is disposed in a path through which the molten metal is flowed to be introduced into the mold, and before the sonicated molten metal is introduced into the mold, heat energy of the molten metal is radiated to the outside to reduce the temperature of the molten metal. To this end, a metal having high thermal conductivity, for example, copper or a copper alloy may be used in the subcooling unit.

For example, in the gravity casting method, the subcooling unit is disposed above an injection port of a mold into which the molten metal is injected, and may include an inclined portion inclined at a predetermined angle so that the molten metal can flow to the injection port of the mold. The sonicated molten metal is first tapped into the supercooling unit, and the molten metal is cooled by the supercooling unit while flowing to the injection port of the mold along the inclined surface of the subcooling unit, thereby reducing the temperature. The supercooled molten metal while flowing through the subcooling treatment unit is introduced into a mold and then solidified to become a main alloy.

The subcooling unit and the mold may be connected by direct contact. In this case, optionally, a heat insulating portion may be formed between the mold and the subcooled portion to block heat transfer between the mold and the subcooled portion.

The supercooling unit serves to reduce the temperature of the molten metal before the molten metal is introduced into the mold, and therefore, it is necessary to maintain the temperature at a low temperature so that the molten metal can be sufficiently subcooled before being introduced into the mold. On the other hand, in the case of a mold, it may be necessary to heat the mold to a predetermined temperature before injection of the molten metal in order to secure the injection property and fluidity of the molten metal. For example, in the case of injecting an aluminum alloy molten metal, the supercooling unit is maintained in the range of 20 to 50°C, which is lower than that of the mold, while the mold can be maintained in the range of 100 to 300°C.

When the subcooling unit and the mold are directly connected, heat is transferred from the high-temperature mold to the low-temperature subcooling unit, thereby increasing the temperature of the subcooling unit. When the temperature of the subcooling unit increases due to the heat transferred from the mold, subcooling of the molten metal for the purpose of installing the supercooling unit may not be sufficiently performed. In particular, when casting is continuously performed multiple times, the temperature of the subcooling unit continues to increase as the casting proceeds, so that the effect of the subcooling of the actual molten metal gradually decreases depending on the number of castings.

In order to solve this problem, a heat insulating part for blocking heat transfer from the mold to the subcooled part may be installed at a portion where the mold and the subcooled part directly contact each other. For example, the heat insulating part may have a shape in which one surface is coupled to a part of the supercooled part and the other surface is in contact with a part of the mold between the supercooled part and the mold. Heat transfer from the mold having a high temperature to the subcooling unit having a low temperature is blocked by the heat insulation unit, and thus, an increase in the temperature of the subcooling unit can be suppressed.

The material of this heat insulating part may be any one of calcium silicate (Lumiboard), rock wool, glass fiber, and ceramic fiber.

2 to 5 are diagrams schematically illustrating an ultrasonic processing address system and a casting method using the same according to embodiments of the present invention.

Referring to FIG. 2, the ultrasonic treatment casting system 200 according to the first embodiment includes an ultrasonic treatment device 210, a melting furnace 220, a subcooling unit 240, and a mold 250. Optionally, it may further include a molten metal collecting unit 230.

The ultrasonic processing apparatus 210 includes a power facility for generating ultrasonic waves and a horn capable of radiating ultrasonic waves in the molten metal by receiving power from the power facility. The horn may be made of a heat-resistant metal, for example, a metal material such as Ti or Mo, or a ceramic material such as Sialon.

The molten metal collecting unit 230 is a means for collecting at least a portion of the molten metal in the melting furnace 220 and then moving it to the mold 250, and may repeatedly move back and forth between the melting furnace 220 and the mold 250.

The ultrasonic treatment may be performed in the melting furnace 220 or may be performed in the molten metal collecting unit 230. For example, when the ultrasonic treatment in the melting furnace 220 is completed, the hot water may be immediately tapped from the melting furnace 220 to the mold 250. As another example, when using the molten metal collecting unit 230, the molten metal collecting unit 230 collects a part of the molten metal from the melting furnace 220 and then moves to the mold 250, and then moves the horn to the molten metal collecting unit 230. After the ultrasonic treatment is completed by inputting, it may be immediately tapped into the mold 250.

The subcooling unit 240 may be in the shape of a plate inclined at a predetermined angle so that the molten metal can flow into the injection hole of the mold 250. At this time, a molten metal transfer path (not shown) through which molten metal can stably flow may be formed in a groove shape on one surface of the plate. The molten metal, which has been subjected to ultrasonic treatment in the melting furnace 220, is partially moved by the molten metal collecting unit 230 and then injected into the subcooling unit 240. The molten metal injected into the subcooling unit 240 is subjected to subcooling while flowing down the molten metal moving path by gravity, and is finally introduced into the mold 250.

Optionally, a heat insulating part 260 may be formed in a region of the end of the subcooling part 240 in direct contact with the upper surface of the mold 250. Through this, heat transfer from the mold 250 to the subcooling unit 240 in the casting process is suppressed.

3 shows an ultrasonic treatment casting system 300 according to a second embodiment of the present invention. Referring to FIG. 3, the second embodiment is the same as the first embodiment except that the shape of the subcooling unit 340 is different. According to the second embodiment, the supercooling treatment unit 340 may be designed to perform a supercooling treatment before the molten metal is injected into the mold 350 by being coupled to the injection port of the mold 350. Optionally, a heat insulating part 360 may be formed between the mold 350 and the subcooling part 340.

4 is a cross-sectional view of the subcooling unit 340 in a form capable of being coupled to an injection port of a mold. 4A and 4B are cross-sectional views and plan views of the subcooling unit 340, and (c) is a cross-sectional view in a state in which the mold 350 is coupled.

4A and 4B, the subcooling unit 340 is formed in the main body 341 and the main body 341, and an inclined surface 342a inclined to allow the molten metal to flow downward, and It is provided with a molten metal transfer path 342 including an outlet (342b). Optionally, the main body 341 may further include a seating surface 344 that allows the main body 341 to be seated on the upper surface of the mold 350 when combined with the injection hole of the mold 350.

Referring to FIG. 4C, when molten metal is injected into the supercooling unit 340 coupled to the upper portion of the mold 350, the molten metal is formed of the mold 350 along the inclined surface 342a of the molten metal transfer path 342. After flowing inward, it is introduced into the mold 350 through the outlet 342b. By controlling the angle of the slope of the molten metal moving path 342 of the subcooling treatment unit 350, the total moving distance of the molten metal, and the like, optimization of the degree of subcooling according to the type of alloy may be implemented.

Optionally, the heat insulating part 360 is formed between the upper surface of the mold 350 and the seating surface 344 of the body 341, so that heat transfer from the mold 350 to the body 341 may be suppressed.

Optionally, the subcooling unit 340 may include a cooling passage 345 through which a cooling medium can flow inside the main body, as shown in FIG. 3. It is possible to control the degree of subcooling more effectively and precisely through the cooling passage 345.

5 shows an ultrasonic treatment casting system 500 according to a third embodiment of the present invention. Referring to FIG. 5, the ultrasonic treatment casting system 500 includes an ultrasonic treatment device 510, a melting furnace 520, a tilting ultrasonic treatment furnace 530, a subcooling treatment unit 540, and a mold 550.

The subcooling unit 540 has a plate shape connecting the ultrasonic treatment furnace 530 and the mold 550 to each other. Specifically, one end of the plate-shaped subcooling unit 540 is connected to the inlet of the ultrasonic treatment furnace 530, and the other end is connected to the upper surface of the mold 550 in which the injection hole is formed. After the ultrasonic treatment in the melting furnace 520 is completed, a part of the molten metal from the melting furnace 520 is injected into the ultrasonic treatment furnace 530. Since the ultrasonic treatment furnace 530 is a tilt type, it can be tilted at a predetermined angle. When the ultrasonic treatment furnace 530 is tilted after a predetermined molten metal is injected into the ultrasonic treatment furnace 530, the subcooling treatment unit 540 and the mold 550 connected thereto are also interlocked and tilted. The molten metal flows down along the plate-shaped subcooling unit 540 and is introduced into the mold 550, and subcooling occurs while flowing along the subcooling unit 540. The mold 550 may be detachably connected to the subcooling unit 540. Therefore, after the casting is completed, the mold 550 may be detached from the subcooled treatment unit 540 and then the main alloy may be obtained.

In the case of the present embodiment, one end of the plate-shaped subcooling unit 540 is connected to the ultrasonic treatment furnace 530 and the other end is connected to the mold 550. Accordingly, insulation portions 560a and 560b are formed at the connection portion between the ultrasonic treatment furnace 530 and the subcooling unit 540 and the connection between the subcooling unit 540 and the mold 550. As a modification, only one of the heat insulating portions 560a and 560b may be formed.

Hereinafter, embodiments for aiding understanding of the present invention will be described. However, the following experimental examples are only to aid understanding of the present invention, and the present invention is not limited to the following examples.

<Experimental Example>

For the experiment, aluminum cast alloy samples were prepared under various conditions. The composition of the aluminum alloy sample was designed into three types as shown in Table 1. 5 kg of the alloy corresponding to each composition was dissolved and degassed with GBF. The ultrasonic treatment was performed for 60 seconds after putting a ceramic horn into the melting furnace. A hollow cooling plate having an inclined cooling plate inside was used for the subcooling of the molten metal. The cooling plate was manufactured using copper having high thermal conductivity. The tapping was performed by injecting 1.5 kg into a mold made of copper. Table 2 shows step-by-step process conditions corresponding to the experimental examples and comparative examples. In the present specification and drawings, “UST” and “CP” mean ultrasonic treatment and subcooling treatment using a cooling plate, respectively. Also, “UST+CP” means that both processes have been performed, and “untreated” means that both processes have not been performed.

Composition (wt.%) Si Mg Cu Fe Mn Ti Zn P Al Composition 1 17.95 0.50 4.22 0.25 0.02 0.093 0.026 0.001 Bal. Composition 2 6.96 0.34 0.018 0.10 0.01 0.031 - - Bal. Composition 3 6.07 0.97 2.06 0.11 - 0.027 - - Bal.

Sample Alloy composition CP UST Experimental Example 1 Composition 1 O O Comparative Example 1a Composition 1 X X Comparative Example 1b Composition 1 O X Comparative Example 1c Composition 1 X O Experimental Example 2 Composition 2 O O Comparative Example 2a Composition 2 X X Comparative Example 2b Composition 2 O X Comparative Example 2c Composition 2 X O Experimental Example 3 Composition 3 O O Comparative Example 3a Composition 3 X X Comparative Example 3b Composition 3 O X Comparative Example 3c Composition 3 X O

6 is a result of observing the microstructure of the alloy samples corresponding to Comparative Examples 1a to 1c and Experimental Example 1 in the cast state, and FIG. 7 is an average size and distribution of primary Si (Primary Si) of the samples. It is a graph illustrating

The alloy corresponding to composition 1 is a hypereutectic Al-Si alloy, and in general, primary Si is generated inside the structure during casting. 6 and 7, it can be seen that the particle size of the primary Si (arrow in FIG. 5) of the sample of Comparative Example 1a is 36 μm. However, it can be seen that the particle size of the primary Si was micronized due to the supercooling and ultrasonic treatment to 28 μm for the sample of Comparative Example 1b and 21 μm for the sample of Comparative Example 1c. In the case of Experimental Example 1 sample in which both processes were applied, The size of the particles was 18 μm, and it was confirmed that the particles were finest when compared with the comparative examples. In addition, referring to (b) of FIG. 7, it can be seen that the size distribution of the Si primary crystal is the most uniform in Experimental Example 1.

8 shows changes in tensile strength (UTS) and elongation (Elongation) after T6 heat treatment of the alloy samples corresponding to Comparative Examples 1a to 1c and Experimental Example 1. T6 heat treatment conditions were subjected to solution treatment at a temperature of 495°C for 8 hours, followed by water cooling to a temperature range of 60°C to 80°C, and aging treatment was performed at a temperature of 175°C for 8 hours.

Referring to FIG. 8, in the case of Experimental Example 1, it was confirmed that the tensile strength and elongation characteristics after T6 heat treatment were the most excellent as the size of the primary Si particles became finer compared to Comparative Examples 1a to 1c.

9 is a result of observing the microstructure in the cast state of the alloy samples corresponding to Comparative Examples 2a to 2c and Experimental Example 2 of the present invention, and FIGS. 10 and 11 show the size and size distribution of crystal grains of the samples. It is the result. The alloy corresponding to the composition 2 is a subeutectic Al-Si alloy, and eutectic Si is generally formed inside the structure during casting. Process Si is indicated by an arrow in FIG. 8.

Referring to FIG. 9, it can be seen that the particle size of the process Si of the sample of Comparative Example 2a is the largest as 28 μm, the sample of Comparative Example 2b is 21 μm, and the sample of Comparative Example 2c is 20 μm. , In the case of the sample of Experimental Example 2, it was confirmed that the size of the process Si particles was 19 μm, which was the most micronized.

10 and 11, the grain size of the sample of Comparative Example 2a was the largest as 426 μm, the size of the grain of the sample of Comparative Example 2b was 343 μm, and the size of the grain of the sample of Comparative Example 2c was It was 293 μm, and it was confirmed that the size of the crystal grains of the sample in Experimental Example 2 was the smallest as 258 μm. The distribution of grain size was also the highest in the proportion of refined grains in the sample of Experimental Example 2.

12 is a measurement of changes in tensile strength, yield strength (YS), and elongation of the alloy samples corresponding to Comparative Examples 2a to 2c and Experimental Example 2 after casting.

Referring to FIG. 12, in the case of the sample of Experimental Example 2, it was confirmed that the tensile strength, yield strength, and elongation characteristics were all excellent in the casting state as the size of the process Si particles became finer compared to Comparative Examples 2a to 2c.

13 is a result of observing the microstructure in the cast state of the alloy samples corresponding to Comparative Examples 3a to 3c and Experimental Example 3 of the present invention, and FIGS. 14 and 15 show the size and size distribution of crystal grains of the samples. It is the result. The alloy corresponding to the composition 3 is a subeutectic Al-Si alloy containing Cu and Mg, and a secondary resin phase (SDAS) is generated inside the structure during casting.

13, the size of the secondary resin phase (SDAS) of the sample of Comparative Example 3a was the largest at 26 μm, the size of the secondary resin phase was further refined to 24 μm in Comparative Example 3b, and 22 μm in Comparative Example 3c. However, in the case of the sample of Experimental Example 3, it was confirmed that the size of the secondary resin phase was 20 μm, which was the most micronized.

14 and 15, in this case, in the case of the sonicated comparative example 3c sample, the crystal grain size was 233 μm, which was almost similar to that of the comparative example 3a sample to which no process was applied. Example 2b It exhibited a higher value than the grain size of the sample 210㎛. From this, it can be seen that depending on the alloy system, it may be difficult to realize the refinement of the cast alloy simply by performing ultrasonic treatment.

However, in the case of the sample of Experimental Example 3 in which both the ultrasonic treatment and the subcooling treatment were performed, the size of the crystal grains was 179 μm, which was the smallest compared to the samples of other comparative examples. The distribution of grain size was also the highest in the proportion of refined grains in the sample of Experimental Example 3. From this, it can be seen that the best alloy properties can be obtained when both the ultrasonic treatment and the subcooling treatment are performed.

16 is a measurement of changes in tensile strength, yield strength, and elongation after casting of the alloy samples corresponding to Comparative Examples 3a to 3c and Experimental Example 3.

Referring to FIG. 16, it can be seen that in the case of Experimental Example 3, the elongation was slightly reduced compared to Comparative Example 3a, but the tensile strength and yield strength exhibited the best values.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those of ordinary skill in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

200, 300, 500: Ultrasonic treatment casting system
210, 310, 510: ultrasonic processing device
220, 320, 520: melting furnace
230, 330: molten metal collection
240, 340, 540: subcooling processing unit
260, 360, 560a, 560b: insulation
250, 350, 550: mold
341: main body
342: Yongtang Transfer Road
342a: slope
342b: exit
344: seating surface
345: cooling flow path
530: ultrasonic treatment furnace

Claims (27)

Melting furnace;
An ultrasonic treatment device capable of ultrasonicating the molten metal melted by the melting furnace;
A supercooling unit capable of subcooling the sonicated molten metal; And
Including; a mold into which the supercooled molten metal is added,
The subcooling treatment unit,
The molten metal is disposed in the flow path to be introduced into the mold,
Sonication casting system. delete The method of claim 1,
A heat insulation part is formed between the subcooling part and the mold,
Sonication casting system. The method of claim 3,
Part of the subcooling treatment unit is coupled to one surface of the heat insulating unit, and a part of the mold is coupled to the other surface of the insulating unit,
Sonication casting system. The method of claim 3,
The heat insulating portion includes any one or more of calcium silicate, rock wool, glass fiber and ceramic fiber,
Sonication casting system. The method of claim 1,
The subcooling treatment unit,
In contact with the molten metal to radiate heat energy of the molten metal to the outside,
Sonication casting system. The method of claim 1,
The subcooling treatment unit,
It is disposed above the injection port of the mold, and has a plate shape inclined with a predetermined angle so that the molten metal can flow to the injection port of the mold,
Sonication casting system. The method of claim 7,
A molten metal transfer path through which the molten metal can flow is formed on one side of the plate,
Sonication casting system. The method of claim 1,
The subcooling treatment unit,
Combined with the top of the injection port of the mold and arranged to perform a subcooling treatment before the molten metal is introduced into the mold,
Sonication casting system. The method of claim 9,
The subcooling treatment unit,
main body; And
A molten metal transfer path formed inside the main body and including an inclined surface inclined to allow the molten metal to flow downward and an outlet through which the molten metal is discharged into the mold;
Containing,
Sonication casting system. The method of claim 10,
The main body includes a seating surface that is seated on one surface of an upper portion of the injection hole of the mold,
A heat insulating portion is formed between the top surface of the injection port of the mold and the seating surface of the body,
Sonication casting system. The method of claim 10,
Further comprising a cooling passage through which the cooling medium can flow inside the body,
Sonication casting system. The method of claim 1,
It further includes a tilt-type ultrasonic treatment furnace,
The subcooling unit is in the form of a plate, one end is connected to the ultrasonic treatment furnace, the other end is connected to the mold,
Sonication casting system. The method of claim 13,
A heat insulation part is formed in at least one of the connection part of the subcooling treatment part and the ultrasonic treatment furnace, and the connection part of the subcooling treatment part and the mold,
Sonication casting system. The method according to any one of claims 1, 3 to 14,
The subcooling treatment unit is made of copper or a copper alloy,
Sonication casting system. Ultrasonicating the molten metal;
Subcooling the sonicated molten metal; And
Injecting the supercooled molten metal into a mold and solidifying;
Including,
The step of subcooling treatment,
Performed in a path through which the molten metal flows to be introduced into the mold,
Manufacturing method of the main cooperative gold using ultrasonic treatment. delete The method of claim 16,
The step of subcooling treatment,
Including the step of direct contact with the subcooling treatment portion disposed in the path to radiate thermal energy of the molten metal to the outside,
Manufacturing method of the main cooperative gold using ultrasonic treatment. The method of claim 16,
The step of subcooling treatment,
Comprising the step of cooling the molten metal while flowing along an inclined surface inclined to the injection port of the mold at a predetermined angle,
Manufacturing method of the main cooperative gold using ultrasonic treatment. The method of any one of claims 16, 18 and 19,
The molten metal contains an aluminum alloy,
Manufacturing method of the main cooperative gold using ultrasonic treatment. As a mold assembly for casting ultrasonically treated molten metal,
A mold into which the sonicated molten metal is injected; And
Including; is disposed above the injection hole of the mold, and in contact with the molten metal to heat the heat energy of the molten metal to the outside;
Mold assembly for the manufacture of main alloy. The method of claim 21,
A heat insulation part is formed between the subcooling part and the mold,
Mold assembly for the manufacture of main alloy. The method of claim 22,
Part of the subcooling treatment unit is coupled to one surface of the heat insulating unit, and a part of the mold is coupled to the other surface of the insulating unit,
Mold assembly for the manufacture of main alloy. The method of claim 22,
The heat insulating portion includes any one or more of calcium silicate, rock wool, glass fiber and ceramic fiber,
Mold assembly for the manufacture of main alloy. The method of claim 21,
The subcooling treatment unit,
main body; And
A molten metal transfer path formed inside the main body and including an inclined surface inclined to allow the molten metal to flow downward and an outlet through which the molten metal is discharged into the mold;
Containing,
Mold assembly for the manufacture of main alloy. delete The method of claim 21,
The subcooling treatment unit,
Made of copper or copper alloy,
Mold assembly for the manufacture of main alloy.

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