KR20040027265A - Manufacturing method of billet for thixocasting method and manufacturing apparatus thereof - Google Patents

Abstract

PURPOSE: A method and an apparatus for manufacturing billet for thixoforming are provided to obtain more fine and uniformed spheroidized grains, improve energy efficiency, reduce manufacturing cost, improve mechanical properties, simplify casting process, shorten manufacturing period of time and shortly and continuously manufacture a plural thixoforming billets having high quality. CONSTITUTION: The method for manufacturing billet for thixoforming comprises a step of forming a metal slurry by impressing an electromagnetic field to a region formed between the first plunger and second plunger of a sleeve into one end of which first plunger is injected, and into the other end of which second plunger is injected and injecting molten metal into the region of the sleeve; a step of forming billet by pressing and cooling the first plunger in a direction of the second plunger; and a step of discharging the billet by transferring the billet in the direction of the second plunger, wherein the method comprises a step of forming a plural billets between the billet forming step and the billet discharging step by repeating the electromagnetic field impressing step, the metal slurry forming step and the billet forming step after forming a certain region between the first plunger and the billet so that the certain region corresponds to the region formed between the first plunger and the second plunger in the electromagnetic field impressing step.

Description

Manufacturing method and apparatus for manufacturing billet for semi-melting molding {Manufacturing method of billet for thixocasting method and manufacturing apparatus

The present invention relates to a method for producing a billet for semi-molten molding and an apparatus thereof, and more particularly, to a method for producing a billet for semi-molten molding which can be finely and uniformly crystallized.

In addition to the reaction solidification method, the thixoforming method is also called the reaction solid / semi-molding method, in which a solidified metal slurry having a predetermined viscosity is cast or not solidified by rheocasting. Forging is a processing method for producing a billet or a final molded product. The semi-melt molding method is a method in which the billet produced by the reaction molding method is reheated to a slurry in a semi-molten state and then cast or forged to produce the final product. The processing method. Here, the reaction solid metal slurry can be deformed by a small force due to thixotropic properties in the state where the liquid crystal and the spherical crystal grains are mixed at an appropriate ratio at the temperature of the reaction solid region. As described above, it means a metal material which is easily formed and processed.

The reaction solid / semi-molten molding method has various advantages over the general molding method using molten metal such as casting or molten forging. For example, the slurry used in the reaction solid / semi-melt molding method has fluidity at a lower temperature than molten metal, so that the temperature of the die exposed to the slurry can be lower than that of molten metal, resulting in longer die life. Can be long. In addition, turbulence is less generated when the slurry is extruded along the cylinder, thereby reducing the incorporation of air during the casting process, thereby reducing the generation of pores in the final product. In addition, there is little solidification shrinkage, workability is improved, the mechanical properties and corrosion resistance of the product is improved, and the weight of the product is possible. Accordingly, it can be used as a new material in the automotive and aircraft industries, and electrical and electronic information communication equipment.

As described above, in the case of the semi-molten molding method, the billet produced by the reaction solidification molding method is used. In the conventional reaction solidification molding method, when the molten metal is cooled, it is mainly stirred at a temperature below the liquidus line to produce the resin phase ( dendrite was formed into spherical particles suitable for reaction solidification by destroying the crystal structure. Mechanical stirring, electromagnetic stirring, gas bubbling, low frequency, high frequency or Agitation method using electromagnetic vibration or electric shock has been used.

For example, U. S. Patent No. 3,948, 650 discloses a method and apparatus for preparing a liquid-solid mixture, in which the molten metal is cooled with vigorous stirring while solidifying. In addition, the disclosed solid metal slurry production apparatus is stirred by a stir bar while injecting a solid-liquid mixture into a vessel, which stirs the solid-liquid mixture having a predetermined viscosity to flow the resinous structure in the mixture. To crush or disperse the crushed dendritic structure. In the manufacturing method as described above, to obtain spherical crystals by grinding the dendritic crystal form already formed in the cooling process as a crystal nucleus, the cooling rate decreases and the manufacturing time increases due to the latent heat generated by the formation of the initial solidification layer And uneven crystal states due to temperature unevenness in the stirring vessel. In addition, in the case of the manufacturing apparatus, due to the limitations of mechanical agitation, the temperature distribution in the container is non-uniform, and because it operates in the chamber, there is a limit that is very difficult to link to the working time and subsequent processes.

U.S. Patent No. 4,465,118 discloses a method and apparatus for producing a semi-solid alloy slurry, in which a cooling manifold and a mold are sequentially provided inside an electromagnetic field applying means having a coil. The upper side is formed so that molten metal is continuously injected, and cooling water flows to the cooling manifold to cool the mold. In the method for producing a high-temperature alloy slurry, first, molten metal is injected from the upper side of the mold, and the molten metal passes through the mold to first form a solidification zone by a cooling manifold, where The magnetic field is applied by the electromagnetic field applying means, the cooling proceeds while crushing the dendritic tissue, and finally an ingot is formed from the bottom. By the way, also in such a manufacturing method and apparatus, the basic technical idea is that after solidification occurs, vibration is applied to break up the dendritic structure, which also has many problems in the above-described process and structure structure. In addition, in the case of the manufacturing apparatus, it is very difficult to control the state of the metal by forming the ingot continuously as the molten metal proceeds from the top to the bottom, or by continuously growing it, and the overall process control is difficult. In addition, there is a limit in that the temperature difference in the vicinity of the wall of the container and in the vicinity of the center of the container is severe because the container is already water-cooled at the stage before the electromagnetic field is applied.

In addition, as described below, the reaction solid / semi-melt molding method is present in various ways, but all have the same problem as the aforementioned patents based on the technical idea of crushing the already formed dendritic tissue and using it as a crystal nucleus. I have it.

U.S. Patent 4,694,881 discloses a dendritic tissue formed from molten metal which is heated by heating the alloy so that all metal components in the alloy are in a liquid state, then cooling the resulting liquid metal to a temperature between the liquid and solid phase lines and then applying a shear force. Disclosed is a method of making thixotropic materials by fracture.

Japanese Laid-Open Patent Publication No. 11-33692 discloses that molten metal is injected into a container at or near the liquidus temperature or up to 50 ° above the liquidus temperature, and then at least a part of the molten metal is cooled to the liquidus temperature during cooling of the molten metal. At the time of the following, that is, the first time passing through the liquidus temperature, by applying a motion to the molten metal, for example by ultrasonic vibration, and then gradually cooled to prepare a metal slurry for reaction solid casting having a granular crystal metal structure A method is disclosed. However, also in this method, force such as ultrasonic vibration is used to break up the dendritic crystal structure formed in the initial stage of cooling. When the pouring temperature is set higher than the liquidus temperature, it is difficult to obtain a crystalline form of granules, and at the same time, it is difficult to rapidly cool the molten metal. In addition, the structure of the surface portion and the central portion becomes uneven.

In addition, in the method for forming a semi-molten metal disclosed in Japanese Patent Laid-Open No. 10-128516, the molten metal is injected into a container, and the vibration bar is deposited in the molten metal to vibrate in contact with the molten metal to vibrate in the molten metal. To give. Accordingly, the vibration force of the vibration bar is transmitted to the molten metal, thereby forming an alloy in a solid-liquid coexisting state having crystal nuclei below the liquidus temperature, and then cooling the molten metal in the container to a molding temperature indicating a predetermined liquidity rate. By holding for 30 to 60 minutes, the crystal nuclei are grown to obtain a semi-molten metal. However, the size of the crystal nuclei obtained by this method is about 100 mu m, the process time is also long, and there is a problem that it is difficult to apply to a container having a predetermined size or more.

US Pat. No. 6,432,160 discloses a method for producing a semi-molten metal slurry by precisely controlling cooling and stirring simultaneously. Specifically, after injecting molten metal into the mixing vessel, a stator assembly installed around the mixing vessel is operated to generate sufficient magnetomotive force to rapidly stir the molten metal in the vessel. The temperature of the molten metal is rapidly lowered by using a thermal jacket installed around the mixing vessel and precisely controlling the temperature of the container and the molten metal. When the molten metal is cooled, the molten metal is continuously stirred and adjusted in such a way as to provide rapid agitation when the solid fraction is low and to provide increased electromotive force as the solid phase increases.

Conventional reaction / semi-melting methods and apparatuses as described above utilize shear forces to crush the dendritic crystal forms already formed during cooling to form granular metal structures. That is, at least a part of the molten metal is applied only when the temperature drops below the liquidus line to avoid a variety of problems such as a decrease in cooling rate and an increase in manufacturing time due to latent heat generation due to the formation of an initial solidification layer. it's difficult. In addition, it is difficult to obtain a uniform and fine structure as a whole due to the temperature non-uniformity in the container, and the non-uniformity of the tissue due to the temperature difference between the wall portion of the container and the center of the center is not achieved unless the temperature of injection of molten metal into the container is controlled. Will be further increased.

The present invention is to solve the problems as described above, to obtain finer and more uniform spheroidized particles and at the same time can realize the advantages of improved energy efficiency, reduced manufacturing costs, improved mechanical properties, simplified casting process and shorter manufacturing time It is an object of the present invention to provide a method and apparatus for producing a semi-molten billet.

Another object of the present invention is to provide a method and apparatus for producing a semi-melt molding billet which can continuously produce a plurality of high quality semi-melt molding billets in a short time.

1 is a graph showing a method of manufacturing a billet for semi-melting molding of the present invention,

2 to 7 is a configuration diagram sequentially showing the configuration and operation of the apparatus for producing a billet for semi-melting molding according to an embodiment of the present invention,

8 to 10 are configuration diagrams sequentially showing the configuration and operation of the apparatus for producing a billet for half melt molding according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: stirring portion 11: space portion

12,13: coil device for applying electromagnetic field 2: sleeve

21: slurry production area 22: tanggu

25: thermostat 28: outlet

31: first plunger 32: second plunger

4: injection vessel 51: reaction metal slurry

In order to achieve the above object, the present invention provides an electromagnetic field to the region formed between the first plunger and the second plunger of the sleeve, the first plunger is inserted at one end, the second plunger is inserted at the other end, Injecting molten metal into a region to form a metal slurry; compressing and cooling the first plunger in the direction of the second plunger to form a billet; and transferring the billet in the direction of the second plunger. It provides a method for producing a semi-molten billet billet comprising the step of ejecting.

According to another feature of the invention, between the step of forming the billet and the discharge step, between the first plunger and the billet to correspond to the area formed between the first plunger and the second plunger in the electromagnetic field applying step After forming a predetermined region, the method may include forming a plurality of billets by repeating the electromagnetic field applying step, the metal slurry forming step, and the billet forming step.

According to another feature of the invention, the application of the electromagnetic field may be made before injecting molten metal into the region of the sleeve.

According to another feature of the invention, the application of the electromagnetic field may be made at the same time as injecting molten metal into the region of the sleeve.

According to another feature of the invention, the application of the electromagnetic field may be made during the injection of molten metal into the region of the sleeve.

According to another feature of the invention, the application of the electromagnetic field can last until at least the solid phase rate of the molten metal in the region of the sleeve reaches 0.001 to 0.7, preferably it can last until 0.001 to 0.4 More preferably 0.001 to 0.1.

According to another feature of the present invention, the step of cooling the molten metal after injecting the molten metal in the region of the sleeve to which the electromagnetic field is applied.

According to another feature of the invention, the cooling step may include the step of cooling the molten metal until a solid phase rate of 0.1 to 0.7.

According to another feature of the invention, the cooling step may cool the molten metal at a rate of 0.2 ℃ / s to 5.0 ℃ / s.

According to another feature of the invention, the cooling step may cool the molten metal at a rate of 0.2 ℃ / s to 2.0 ℃ / s.

In order to achieve the above object, the present invention also provides a stirring part for providing an electromagnetic field to the space part and having a space part therein, and installed to penetrate the space part, and corresponding to the space part to which the electromagnetic field is applied. A first plunger inserted into one end of the sleeve to insert a molten metal into a region, and forming one wall of the region in which the molten metal is accommodated in the sleeve, and pressurizing the manufactured slurry; Inserted into the other end of the sleeve to form the other wall of the region in which the molten metal is accommodated, and fixed when the first plunger presses the slurry to form a billet of a predetermined size and then retracted It provides a device for producing a billet for semi-melting molding comprising a second plunger.

According to another feature of the invention, the outlet for discharging the billet in the lower portion in the outer side in the direction of the second plunger from the region in which the molten metal of the sleeve is accommodated.

According to another feature of the invention, the stirring unit may apply an electromagnetic field before the molten metal is injected into the sleeve.

According to another feature of the invention, the stirring portion may be applied to the electromagnetic field while the molten metal is injected into the sleeve.

According to another feature of the invention, the stirring unit may apply an electromagnetic field while the molten metal is injected into the sleeve.

According to another feature of the invention, the agitating part may continue to apply the electromagnetic field until at least the solid phase rate of the molten metal in the sleeve reaches 0.001 to 0.7, preferably until it reaches 0.001 to 0.4 It may be, and more preferably may last until 0.001 to 0.1.

According to another feature of the invention, the sleeve may be further added to the temperature control device.

According to another feature of the invention, the temperature control device may be provided with at least one of a cooling device installed in the sleeve and an electric heater provided on the outer wall of the sleeve.

According to another feature of the invention, the temperature control device may cool the molten metal in the sleeve until a solid phase rate of 0.1 to 0.7.

According to another feature of the invention, the temperature control device can cool the molten metal in the sleeve at a rate of 0.2 ℃ / s to 5.0 ℃ / s.

According to another feature of the invention, the temperature control device can cool the molten metal in the sleeve at a rate of 0.2 ℃ / s to 2.0 ℃ / s.

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

The semi-molten billet according to the present invention refers to the billet to be used in the semi-molten molding method, which is produced by the reaction solidification method. Therefore, the method for producing a semi-melt molding billet of the present invention is basically based on a reaction solid-forming method. Hereinafter, a method of making a semi-melt molding billet according to the present invention, that is, a reaction solid-molding method will be described below. This will be described with reference.

Unlike the conventional techniques described above, in the reactive solidification method of the present invention, a molten metal is injected into a sleeve to prepare a slurry, and then press-molded to produce a billet having a predetermined size. At this time, in this invention, stirring by an electromagnetic field is performed before injection of molten metal into the said sleeve is completed. In other words, before the molten metal is injected into the sleeve, the formation of the initial dendritic tissue is blocked by the stirring by the electromagnetic field simultaneously with the molten metal into the sleeve or during the molten metal into the sleeve. In this case, ultrasonic waves may be used instead of the electromagnetic field as the stirring. This will be described in more detail as follows.

That is, an empty sleeve is disposed without molten metal pouring into a predetermined space, and an electromagnetic field is applied to a predetermined region of the empty sleeve. At this time, the application of the electromagnetic field is made of an intensity capable of stirring the molten metal.

Next, as can be seen in Figure 1, the molten metal is injected into the sleeve at the pouring temperature Tp, at this time, the electromagnetic field is applied to the sleeve may be in a state where stirring is made. However, the present invention is not necessarily limited thereto, and the electric field agitation may be performed simultaneously with molten metal pouring, or electromagnetic agitation may be performed while the molten metal is pouring.

As the electromagnetic agitation is performed before the injection of molten metal into the sleeve is completed, the molten metal does not grow from the initial solidification layer in the inner wall of the low temperature sleeve into the dendritic structure, and fine crystal nuclei are formed throughout the sleeve. At the same time, the entire molten metal in the sleeve can be rapidly cooled uniformly below the liquidus temperature to generate a plurality of crystal nuclei simultaneously.

This is due to active initial agitation by applying an electromagnetic field before or at the same time as injecting the molten metal into the sleeve, so that the inner molten metal and the molten metal on the surface are well stirred, so that heat transfer in the molten metal occurs quickly. This is because initial solidification layer formation is suppressed. In addition, convective heat transfer between the well-stirred molten metal and the low temperature inner sleeve wall increases, thereby rapidly cooling the temperature of the entire molten metal. That is, the injected molten metal is dispersed into the dispersed particles by electromagnetic field stirring at the same time as the injection, and the dispersed particles are evenly distributed in the sleeve as crystal nuclei, so that a temperature difference does not occur throughout the sleeve. On the other hand, according to the prior arts, the injected molten metal is brought into contact with the inner sleeve of the low temperature sleeve and grows into dendritic crystals in the initial solidification layer in the inner sleeve wall by rapid convective heat transfer.

This principle may be explained with reference to the latent heat of solidification, that is, no initial solidification of the molten metal at the wall surface of the sleeve occurs, so that no latent heat of solidification occurs, so that cooling of the molten metal is only performed by the molten metal. It is possible to release only the amount of heat corresponding to the specific heat (only about 1/400 of the latent heat of coagulation). Therefore, the molten metal in the sleeve exhibits a uniform and rapid temperature drop throughout the center from the wall surface of the sleeve without forming dendritic crystals, which are initial solidification layers generated on the inner wall surface of the sleeve as in the prior art. The time it takes is only a short time of about 1 to 10 seconds after the injection of molten metal. As a result, a large number of crystal nuclei are uniformly generated throughout the molten metal in the sleeve, and the distance between the crystal nuclei becomes very short due to an increase in the nucleation density of the nuclei. Thus, dendritic crystals do not form and grow independently to form spherical particles Will form.

The same is true when an electromagnetic field is applied while molten metal is being poured. In the case where an electromagnetic field is applied while molten metal is being poured, although the initial solidification layer is formed on the inner wall of the sleeve, the initial solidification layer no longer grows into the dendritic structure by stirring the electromagnetic field during the injection process. You will not lose. The effects thereafter are as described above.

At this time, the pouring temperature Tp (pouring temperature) of the molten metal is preferably maintained at a temperature between the liquidus temperature to the liquidus + 100 ℃ (melt superheat degree, melt superheat = 0 ~ 100 ℃). As described above, since the entire inside of the sleeve containing molten metal is uniformly cooled, there is no need to cool the liquidus temperature near the liquidus temperature before injecting the molten metal into the sleeve, and the temperature may be maintained at about 100 ° C above the liquidus temperature. Because On the other hand, in the conventional method of applying the electromagnetic field to the container when the molten metal is injected into the slurry production vessel and a part of the molten metal is below the liquidus line, the initial solidification layer is formed on the wall of the container, and the latent heat of solidification is generated. Since the latent heat of coagulation is about 400 times the specific heat, it takes a lot of time for the temperature of the molten metal of the entire container to drop. Therefore, in this conventional method, it was common to cool the temperature of the molten metal to a temperature of about 50 ° C. above the liquidus level or to inject it into a container. However, at this time, it is necessary to wait until the temperature of the molten metal to be injected reaches an appropriate temperature, which is very difficult in the actual process.

In addition, in the present invention, when the magnetic field agitation is finished, as shown in FIG. 1, even when at least a portion of the molten metal in the sleeve is lowered below the liquidus temperature T ₁ , that is, the solid phase If the rate is set to about 0.001 or even predetermined crystal nuclei, there is no big problem even if the electromagnetic agitation is terminated at any time. That is, the electromagnetic field agitation may be applied until the molten metal is injected into the sleeve, the molten metal is cooled, and / or the formation of the billet according to subsequent pressurization. This is because the magnetic field agitation at the stage of crystal grain growth around the crystal nuclei does not affect the properties of the metal slurry to be produced because the nuclei are evenly distributed throughout the slurry manufacturing region of the sleeve.

However, the above-mentioned electromagnetic field stirring may be applied only during the manufacture of the metal slurry in the sleeve, and thus, at least until the solid phase rate of the molten metal reaches any time of 0.001 to 0.7, and in terms of energy efficiency, It can last at least until the solid phase rate of the molten metal in the slurry production zone is 0.001 to 0.4, more preferably until the solid phase rate of the molten metal is 0.001 to 0.1.

On the other hand, after the molten metal is injected into the slurry production region of the sleeve to form crystal nuclei with a uniform distribution, the slurry production region is cooled to accelerate the growth of the generated crystal nuclei. Therefore, this cooling step may be performed when the molten metal is injected into the slurry production region. As described above, the electromagnetic field may be continuously applied even during this cooling step.

On the other hand, such a cooling step may be continued until the billet forming process according to the pressurization, which is a subsequent process, according to a preferred embodiment of the present invention, the cooling step to the point (t2) until the molten metal reaches a solid phase rate of 0.1 to 0.7 You can also keep it. At this time, the cooling rate of the molten metal may be about 0.2 ℃ / sec to 5.0 ℃ / sec, which may also be 0.2 ℃ / sec to 2.0 ℃ / sec depending on the distribution of crystal nuclei and fineness of the particles. .

According to this method, a metal slurry in a solid state of a solid state having a predetermined solid phase rate can be prepared, and it is immediately pressurized and cooled to prepare a billet for semi-molding molding.

According to the method as described above, it is possible to significantly shorten the time to prepare the metal slurry in the reaction solid state, from the time of injection of the molten metal into the sleeve into a metal material in the form of a metal slurry with a solid phase of 0.1 to 0.7 The time required to form is only 30 seconds to 60 seconds. When the billet is formed by using the prepared metal slurry, a uniform and dense spherical crystal structure can be obtained.

Based on the reaction solidification method as described above, it is possible to produce a semi-molten billet by the apparatus for producing a semi-molten billet according to a preferred embodiment of the present invention according to Figs.

As shown in FIG. 2, the apparatus for manufacturing a billet for semi-melting molding according to an exemplary embodiment of the present invention includes a space part 11 therein, and coil devices 12 and 13 for applying an electromagnetic field are described above. Stirring part 1 provided to surround the space part 11, a sleeve 2 installed to penetrate the space part 11, and a first plunger 31 inserted into one end of the sleeve 2; ) And a second plunger 32 inserted into the other end of the sleeve 2.

The stirring section 1 includes a space 11 inside, and coil devices 12 and 13 for applying electromagnetic fields are disposed to surround the space 11. The space 11 and the electromagnetic field applying coil devices 12 and 13 are fixed by a separate frame structure (not shown). The coil device 12 and 13 for applying an electromagnetic field are provided to emit an electromagnetic field having a predetermined intensity toward the space 11, and the molten metal injected into the sleeve 2 penetrating through the space 11. Electromagnetic agitation, and electrically connected to a control unit (not shown) to adjust the strength and operating time. Coil device 12, 13 for applying the electromagnetic field as described above may be applied to any coil device that can be used for conventional electromagnetic stirring, in addition to the ultrasonic stirring device may be used.

On the other hand, the coil device 12, 13 for applying the electromagnetic field is, as can be seen in Figure 2, inside the sleeve 2, in particular, the slurry manufacturing area 21 formed in the sleeve 2 and the mouth of the sleeve ( An electromagnetic field is applied to the pouring tool 23 extending from 22). The upper coil device 12 may be formed so as to cover the entire pouring jig 23 unlike FIG. 2. Accordingly, the molten metal injected into the sleeve 2 is to be thoroughly stirred from the stage of injection. The application of this electromagnetic field, i.e., electromagnetic agitation by the stirring unit, may be continued until the reaction solid metal slurry produced is compressed, as described above. In other words, the electromagnetic field does not have to be terminated. However, since the electromagnetic agitation can be performed until the manufacturing process of the sleeve 2 in terms of energy efficiency, the electromagnetic agitation can be continued until at least the solid phase ratio is 0.001 to 0.7, and preferably the solid phase ratio is at least 0.001 to 0.4. It can last until it becomes about, More preferably, it can last at least until the solid phase rate is about 0.001 to 0.1. The time to become such a solid phase rate can be found beforehand by experiment.

The sleeve 2 according to the present invention combines the function of a slurry manufacturing vessel for reacting molten metal into a slurry by electromagnetic field stirring and as a forming mold when producing the prepared slurry into a billet. Thus, as described above, the sleeve 2 must be subjected to electromagnetic stirring before the injection of the molten metal is completed.

The first plunger 31 is inserted into one end of the sleeve 2, and the second plunger 32 is inserted into the other end. The first plunger 31 and the second plunger 32 are spaced apart from each other by a predetermined distance to form a predetermined region therebetween. This area becomes the slurry production area 21, the first plunger 31 forms one wall of the slurry production area 21, and the second plunger 32 forms the other wall. An electromagnetic field is applied to the slurry manufacturing region 21 by the stirring unit 1, and liquid molten metal is transferred to the slurry manufacturing region by an injection vessel 4 such as a ladle. 21) is pouring. A spout 22 is formed in the upper portion of the sleeve 2 so that molten metal can be injected therein, and the spout 22 is provided with a funnel-shaped jig for easy pouring from the spout container 4. It extends out of the stirring part 1.

The sleeve 2 may be provided with a metal material, or may be provided with an insulating material such as alumina or aluminum nitride. When provided with a metal material, it is preferable to use the thing whose temperature is higher than the temperature of the molten metal accommodated. Although not shown in the drawings, a separate thermocouple may be embedded, and the thermocouple may be connected to a controller (not shown) to transmit temperature information to the controller.

In a preferred embodiment of the invention as seen in FIG. 2, the sleeve 2 may further comprise a temperature control device 25. The temperature control device 24 may be applied alone or in combination with a cooling device and a heating device. In a preferred embodiment of the present invention as shown in FIG. 2, a cooling device, such as a cooling water pipe 26, may be Like a jacket, it is built in a separate fixing block 27 so as to surround the outside of the sleeve 2, but a heating device (not shown) such as an electric heater may be additionally installed therein. At this time, the electric heater may be a coiled electric heater formed on the outer wall of the sleeve. And of course the thermocouple can be embedded in the sleeve. As shown in FIG. 2, the thermostat device 25 may be installed throughout the sleeve 2, but may be intensively installed only around the sleeve manufacturing area 21.

The molten metal contained in the sleeve 2 is cooled by the thermostat 25 until it reaches a solid phase rate of 0.1 to 0.7. In addition, the cooling rate is also adjusted to cool at a rate of 0.2 to 5.0 ° C./s, preferably at a rate of 0.2 to 2.0 ° C./s. At this time, such cooling may be performed after the stirring of the electromagnetic field is completed, as described above, and may be performed irrespective of the stirring of the electromagnetic field, that is, while the application of the electromagnetic field is continued. It may also be performed from the pouring step of the molten metal. In addition, the temperature control device 25 pressurizes the slurry prepared after the cooling step so that it can be cooled at a higher speed when molding the billet.

Meanwhile, the first and second plungers 31 and 32 respectively inserted into one end and the other end of the sleeve 2 are connected to a separate cylinder device (not shown) to reciprocate the piston in the sleeve 2. Do it. The first plunger 31 forms one wall of the slurry production zone 21 during the application of the electromagnetic field and cooling, that is, during slurry production, and pressurizes the slurry after the slurry production is completed. Is driven to. The second plunger 32 forms the other wall of the slurry production zone 21 during slurry production, and is fixed while the first plunger 31 pressurizes the slurry to form billets of a predetermined size. After that, the billet produced after being retracted forms the slurry manufacturing region 21 again with the first plunger 31.

Next, with reference to Figures 1 to 7 will be described a method for producing a billet for half melt molding of the present invention by the apparatus for producing a billet for half melt molding according to a preferred embodiment of the present invention configured as described above.

First, as shown in FIG. 2, the electromagnetic field is applied at a predetermined frequency and intensity into the space 11 by the coil device 12 and 13 for applying an electromagnetic field in the stirring unit 1. According to a preferred embodiment of the present invention, the electromagnetic field applying coil device may apply an electromagnetic field at 250V, 60Hz, 500Gauss, but is not necessarily limited thereto. Applicable

In this state, the molten metal melted in a separate furnace is transported by an injection vessel 5 such as a ladle and injected into the sleeve 2 under the influence of the electromagnetic field. At this time, the furnace and the sleeve may be directly connected to allow molten liquid molten metal to be directly injected into the sleeve. In addition, the said molten metal at this time may be liquidus temperature + 100 degreeC temperature as mentioned above. In the sleeve 2 into which the molten metal is injected, a predetermined region is formed by the first plunger 31 and the second plunger 32, and this region becomes the slurry manufacturing region 21. In addition, inert gas such as N ₂ or Ar is injected through a separate gas supply pipe 24 in order to prevent oxidation of molten metal, that is, molten metal, before the molten metal is injected into the slurry manufacturing region 21.

As such, when the molten metal, which is completely melted and liquid, is injected into the slurry manufacturing region 21 of the sleeve 2 where electromagnetic stirring is in progress, fine recrystallized particles are distributed throughout the slurry manufacturing region 21, and the recrystallization is performed. The particles grow quickly so that no dendritic structure is produced.

As described above, the electromagnetic field may be applied at the same time as the injection of the molten metal or may be applied during the injection of the molten metal.

In addition, the application of the electromagnetic field may be performed until the billet is formed, as described above, but at least until the solid phase ratio is about 0.001 to 0.7, preferably when the solid phase ratio is about 0.001 to 0.4. And more preferably at least until its solid phase rate is about 0.001 to 0.1. This time can be determined by experiment in advance, and thus applying the electromagnetic field for a fixed time.

After the application of the electromagnetic field is terminated or while the application of the electromagnetic field is continued, the reaction metal is subjected to a cooling step of cooling the molten metal in the slurry production zone 21 at a predetermined rate until a solid phase rate of 0.1 to 0.7 is reached. The slurry 51 is prepared. At this time, the cooling rate may be controlled by the temperature control device 25 installed outside the sleeve 2, that is, the cooling water flowing through the cooling water pipe 26 to be a rate of 0.2 ℃ / sec to 5.0 ℃ / sec. More preferably, it may be a rate of 0.2 ℃ / sec to 2.0 ℃ / sec. The time t2 at which the solid phase ratio reaches 0.1 to 0.7 can be known through experiments in advance.

After the reaction solid metal slurry is manufactured in this way, as shown in FIG. 3, the first plunger 31 is pressed in the direction of the second plunger 32 in a state where the second plunger 32 is fixed. The first billet 52 is formed. Subsequently, the cooling speed can be further increased by the cooling water to rapidly quench.

After the first billet 52 is formed, as shown in FIG. 4, the second plunger 32 and the first billet 52 are further urged by pressing the first plunger 31 in the direction of the second plunger 32. Is transferred in the direction of the second plunger 32. At this time, the transfer of the second plunger 32 may depend on the pressing force of the first plunger 31, but the second plunger 32 may be operated separately.

The transfer distance between the second plunger 32 and the first billet 52 is such that the end portion of the first billet 52 in the direction of the first plunger 31 is the end portion of the second plunger 32 in the direction of the first plunger 31. Make sure you are as far as you can be. As can be seen in FIG. 5, the slurry production zone 21 is again formed by the first plunger 31 and the transferred first billet 52.

Such a step may proceed directly to the step according to FIG. 4 after the step according to FIG. 2. That is, after the slurry is manufactured in the slurry manufacturing region 21, the first plunger 31 pressurizes the slurry while both the second plunger 32 and the first plunger 31 are moved, and thus the first billet as shown in FIG. 4. To form (52). At this time, the first billet 52 is already out of the application region of the electromagnetic field.

After the transfer of the second plunger 32 and the first billet 52 is finished, as shown in FIG. 5, the first plunger 31 and the first billet are returned to their original positions. The slurry manufacturing region 21 is formed by the 52. And the slurry mentioned above is repeated in the slurry manufacturing area 21 formed in this way, and a slurry is manufactured. That is, the reaction solid metal slurry is prepared through the stirring step (S) and the cooling step (C) as shown in FIG. 1. As shown in FIG. 6, the slurry 51 is formed into a second billet 53 having a predetermined size by pressurization of the first plunger 31. Next, after the second plunger 32, the first billet 52 and the second billet 53 are transferred, the first plunger 31 is returned and as shown in FIG. To form. After this, the third and fourth billets are sequentially manufactured by the above-described method.

According to the method and apparatus for producing a semi-molten billet according to the present invention, it is possible to manufacture a plurality of semi-molten billets having excellent quality in succession. The plurality of billets thus prepared may be joined by melting billets adjacent to each other, but the bonding strength is very low so that it can be easily separated when used. The manufactured plurality of continuous billets may be discharged after separating the second plunger 32 in the sleeve 2 or may be discharged through a separate outlet formed in the sleeve 2.

8 to 10 sequentially show a manufacturing apparatus and method for a semi-melt molding billet according to another preferred embodiment of the present invention, the difference from the above-described embodiment is formed by continuously forming a plurality of billets Instead of discharging this, one billet is manufactured in the sleeve and then discharged, and the billet manufacturing process is repeated again. Hereinafter, description will be made mainly on the parts that are distinguished from the above-described embodiment.

As shown in FIG. 8, the apparatus for manufacturing a billet for semi-molding molding according to another exemplary embodiment of the present invention has the same basic structure as the above-described manufacturing apparatus, except that the slurry manufacturing region 21 is second from the slurry manufacturing region 21. The outlet 28 is further provided at a position spaced a predetermined distance in the direction of the plunger 32 to discharge the manufactured billet out of the sleeve 2. The outlet 28 may be formed in a size corresponding to the size of the billet to be formed, but preferably formed larger than the billet so as to manufacture and discharge the billets of various sizes. At this time, the outlet 28 is formed so that the temperature control device 25 at least as much as the portion corresponding to the outlet 28 should be excluded so as not to affect the discharge of the billet.

The apparatus for producing a billet for semi-molten molding according to another preferred embodiment of the present invention configured as described above performs the method for producing a billet for semi-molten molding according to the present invention.

First, as shown in FIG. 8, the molten metal is injected into the injection vessel 5 such as a ladle in a state where electromagnetic stirring is performed in the space 11 by the coil device 12 and 13 for applying an electromagnetic field in the stirring unit 1. Is injected into the sleeve 2 where stirring is carried out. At this time, as described above, the furnace and the sleeve may be directly connected to allow molten liquid molten metal to be directly injected into the sleeve. In addition, the said molten metal at this time may be liquidus temperature + 100 degreeC temperature as mentioned above. The region into which the molten metal is injected is the slurry manufacturing region 21 formed by the first plunger 31 and the second plunger 32. In this slurry production region 21, an inert gas such as N ₂ or Ar is injected through the gas supply pipe 24.

As described above, the electromagnetic field may be applied at the same time as the injection of the molten metal or may be applied during the injection of the molten metal.

After injecting the molten metal, the reaction solid metal slurry 51 is prepared through a cooling step of cooling at a predetermined rate until reaching a solid phase rate of 0.1 to 0.7. At this time, the cooling rate is controlled by the temperature control device 25 installed outside the sleeve 2, that is, the cooling water flowing through the cooling water pipe 26 may be a rate of 0.2 ℃ / sec to 5.0 ℃ / sec. More preferably, it may be a rate of 0.2 ℃ / sec to 2.0 ℃ / sec. On the other hand, the application of the electromagnetic field may be continuously applied as described above, at least until the solid phase rate of the molten metal is about 0.001 to 0.7, preferably lasts until about 0.001 to 0.4. It may be, and more preferably may last until about 0.001 to 0.1.

After preparing the reaction solid metal slurry, as shown in FIG. 9, the first plunger 31 is pressed in the direction of the second plunger 32 while the second plunger 32 is fixed, and then cooled. To form a billet 54 of a predetermined size.

After the billet 54 is formed, as shown in FIG. 10, the first plunger 31 is further pressed in the direction of the second plunger 32 so that the second plunger 32 and the billet 54 are discharged 28. The billet (54) is discharged through the outlet 28 to the direction of the (). At this time, the transfer of the second plunger 32 may be dependent on the pressing force of the first plunger 31, but it is as described above that the second plunger 32 may be operated separately.

After discharging the billet 28 in this manner, the first plunger 31 and the second plunger 32 are returned to their original positions to form the slurry manufacturing region 21, and then the processes of FIGS. 8 to 9 are performed. Repeat this. According to this repetition process, the billet having a fine and uniform tissue can be continuously discharged through the outlet. In addition, unlike the above-described embodiment can be used immediately without cutting the billet manufactured can further increase the efficiency of the process.

As described above, the method and apparatus for producing a semi-melt forming billet of the present invention may be a variety of metals / alloys such as aluminum or alloys thereof, magnesium or alloys thereof, zinc or alloys thereof, copper or alloys thereof, or iron or It is a matter of course that the present invention can be universally applied to reaction solid / semi-melt molding methods of the alloy.

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

First, an alloy having a uniform, fine spherical structure as a whole can be obtained.

Second, the spheroidization of the particles can be realized by remarkably increasing the nucleation density on the wall of the container with only a short time of stirring at a temperature higher than the liquidus.

Third, the improvement of the mechanical properties of the produced alloy can be realized.

Fourth, since the electromagnetic stirring time can be greatly shortened, less energy is required for stirring.

Fifth, the overall process can be simplified, and the product molding time can be shortened, thereby improving productivity.

Sixth, since a plurality of billets can be produced continuously, the mass production applicability is excellent.

In the present specification, the present invention has been described with reference to limited embodiments, but various embodiments are possible within the spirit of the present invention. In addition, although not described, equivalent means will also be referred to as incorporated in the present invention. Therefore, the true scope of the present invention will be defined by the claims.

Claims (25)

An electromagnetic field is applied to an area formed between the first plunger and the second plunger of the sleeve having the first plunger inserted at one end and the second plunger inserted at the other end, and molten metal is injected into the area of the sleeve to form a metal slurry. Forming; Compressing and cooling the first plunger in the direction of the second plunger to form a billet; And And transporting the billet in the direction of the second plunger and discharging the billet. The method of claim 1, Between the step of forming the billet and the discharging step, After forming a predetermined region between the first plunger and the billet to correspond to the region formed between the first plunger and the second plunger in the electromagnetic field applying step, the electromagnetic field applying step, the metal slurry forming step and the Forming a plurality of billets by repeating the billet forming step. The method according to claim 1 or 2, The application of the electromagnetic field is made before the injection of molten metal into the region of the sleeve manufacturing method of the semi-molten billet. The method according to claim 1 or 2, The application of the electromagnetic field is a method of manufacturing a billet for semi-melting molding, characterized in that at the same time as the molten metal is injected into the region of the sleeve. The method according to claim 1 or 2, The application of the electromagnetic field is made in the middle of injecting molten metal into the region of the sleeve manufacturing method of the semi-molten billet. The method according to claim 1 or 2, The application of the electromagnetic field lasts at least until the solid phase rate of the molten metal in the region of the sleeve reaches 0.001 to 0.7. The method of claim 6, The application of the electromagnetic field lasts at least until the solid phase rate of the molten metal in the region of the sleeve reaches 0.001 to 0.4. The method of claim 7, wherein The application of the electromagnetic field lasts at least until the solid phase rate of the molten metal in the region of the sleeve reaches 0.001 to 0.1. The method according to claim 1 or 2, And cooling the molten metal after injecting the molten metal into a region of the sleeve to which the electromagnetic field is applied. The method of claim 9, The cooling step is the manufacturing method of the semi-molten billet for billing comprising the step of cooling the molten metal until a solid phase rate of 0.1 to 0.7. The method of claim 9, The cooling step is a method for producing a billet for semi-melting molding, characterized in that the molten metal is cooled at a rate of 0.2 ℃ / s to 5.0 ℃ / s. The method of claim 9, The cooling step is a method for producing a billet for semi-melting molding, characterized in that the molten metal is cooled at a rate of 0.2 ℃ / 2.0 to 2.0 ℃ / s. A stirring unit having a space inside and applying an electromagnetic field to the space; A sleeve installed to penetrate the space part, the molten metal being injected into a predetermined area corresponding to the space part to which the electromagnetic field is applied; A first plunger inserted into one end of the sleeve to form one side wall of the region in which the molten metal is accommodated and pressurize the prepared slurry; And Inserted into the other end of the sleeve, forming the other wall of the region in which the molten metal is accommodated, and fixed when the first plunger presses the slurry to form a billet of a predetermined size and then retracts Apparatus for manufacturing a billet for semi-melting molding comprising a; 2nd plunger. The method of claim 13, And an outlet for discharging the billet at a lower side of the sleeve from the region in which the molten metal is accommodated in the sleeve toward the second plunger. The method according to claim 13 or 14, The stirring unit is an apparatus for producing a billet for semi-melting molding, characterized in that for applying an electromagnetic field before the molten metal is injected into the sleeve. The method according to claim 13 or 14, The stirring unit is a molten metal is injected into the sleeve and at the same time the apparatus for producing a billet for semi-melting molding characterized in that the application of an electromagnetic field. The method according to claim 13 or 14, The stirring unit is a device for manufacturing a billet for semi-melting molding, characterized in that for applying an electromagnetic field while the molten metal is injected into the sleeve. The method according to claim 13 or 14, The stirring unit is an apparatus for producing a billet for semi-melting molding, characterized in that the application of the electromagnetic field until at least the solid phase rate of the molten metal in the sleeve reaches 0.001 to 0.7. The method of claim 18, The stirring unit is an apparatus for producing a billet for semi-melting molding, characterized in that the application of the electromagnetic field until at least the solid phase rate of the molten metal in the sleeve reaches 0.001 to 0.4. The method of claim 19, The stirring unit is an apparatus for producing a billet for semi-melting molding, characterized in that the application of the electromagnetic field until at least the solid phase rate of the molten metal in the sleeve reaches 0.001 to 0.1. The method according to claim 13 or 14, The apparatus for manufacturing a billet for semi-melt molding, characterized in that the temperature control device is further added to the sleeve. The method of claim 20, The temperature control device is an apparatus for producing a billet for half melt molding, characterized in that provided with at least one of a cooling device installed in the sleeve and an electric heater installed on the outer wall of the sleeve. The method of claim 20, The temperature control device is an apparatus for producing a billet for semi-melting molding, characterized in that the molten metal in the sleeve is cooled to reach a solid phase rate of 0.1 to 0.7. The method of claim 20, The temperature control device is a device for producing a billet for semi-melting molding, characterized in that for cooling the molten metal in the sleeve at a rate of 0.2 ℃ / s to 5.0 ℃ / s. The method of claim 24, The temperature control device is a device for producing a billet for semi-melting molding, characterized in that for cooling the molten metal in the sleeve at a rate of 0.2 ℃ / 2.0 to 2.0 ℃ / s.