Apparatus for continuous casting a aluminium alloy billet and manufacturing method thereof

Abstract

The present invention relates to a continuous casting apparatus for aluminum alloy billets and a casting method thereof. An aluminum alloy billet continuous casting device according to one embodiment may include a cooling water inlet provided on one side of a mold; a cooling water channel formed in a jacket shape inside the mold; and a cooling water outlet connected to the cooling water channel and provided at the bottom of the mold.

Description

Technology Field

[0001] The present embodiments relate to a continuous casting apparatus for solid solution aluminum alloy billets, and more specifically, to a continuous casting apparatus and a structural method thereof capable of producing a solid solution aluminum alloy billet having a sound surface and no internal cracks, while ensuring uniform cooling capacity. Background Technology

[0002] With the lightweighting of materials for transportation equipment becoming essential due to global warming and the increased use of electric energy, the application of aluminum materials is continuously increasing. To meet required characteristics such as high strength, formability, and corrosion resistance, the amount of various alloying elements added to aluminum alloys is on the rise. In particular, the application scope of wrought aluminum, which offers superior reliability and properties, is growing day by day. Billets and slabs in the form of semi-finished materials for extrusion or rolling are mostly manufactured by continuous casting. However, as the amount of alloying elements added to wrought aluminum increases, a wide solid-liquid coexistence range is required. Consequently, this leads to problems such as solidification cracks and solute segregation during casting. Since these defects prolong the homogenization process of the continuously cast material and cause surface and internal defects during the extrusion process, it is crucial to manufacture sound billets during continuous casting.

[0003] The Direct Chill and Air Slip processes are utilized for the continuous casting of aluminum alloy billets. While such conventional continuous casting methods are suitable for (6000) series alloy billets, they cause surface and internal structure non-uniformity issues, such as cracks occurring during continuous casting, in the case of high-strength alloys containing solid solution alloys.

[0004] The air-slip casting method (Korean registered patent 10-0904506) is a continuous casting method in which gas and oil are supplied into the mold to solidify the molten metal while simultaneously controlling cooling and lubrication with a porous graphite ring. Although it minimizes friction with the mold by supplying gas at a constant pressure into the mold, it is not suitable for the continuous casting of solid solution alloy billets with a diameter greater than a certain amount. Another method is a technology (Japanese registered patent JP (5612881)) which involves horizontally continuous casting of a molten magnesium alloy by cooling it in a cylindrical insulated mold while spraying a cooling liquid onto the surface of the billet. However, this process involves controlling quality by supplying ignition gas into the gap between the billet and the mold while performing horizontal continuous casting, which has limitations in terms of the need for atmosphere control and productivity. Furthermore, as previously explained, while it is suitable for continuous casting of alloys that do not contain many alloying elements, it is not suitable for the continuous casting of solid solution aluminum alloy billets.

[0005] In other words, when using conventional continuous casting equipment, it is particularly difficult to maintain the integrity of solid solution-containing aluminum alloy billets with high amounts of various alloy additives; therefore, the development of an important mold system and a method for continuous casting thereof is required to manufacture solid solution-containing aluminum alloy billets soundly. The problem to be solved

[0006] In this embodiment, we intend to provide technology for a continuous casting apparatus and a casting method for securing uniform cooling capacity during continuous casting while simultaneously controlling thermal shock to the material caused by excessive cooling capacity. means of solving the problem

[0007] An aluminum alloy billet continuous casting apparatus according to one embodiment may include: a cooling water inlet provided inside a mold and provided on one side of the mold; a cooling water channel provided penetrating the interior of the mold and formed along the shape of the outer surface of the mold; and a cooling water outlet connected to the cooling water channel and provided at the bottom end of the mold.

[0008] An aluminum alloy billet continuous casting apparatus according to one embodiment may be formed along a second surface connected to one surface of a mold having a cooling water inlet, a third surface connected to the second surface, and a fourth surface connected to the third surface. Effects of the invention

[0009] According to the present invention, an aluminum alloy billet having a sound surface and no internal cracks can be easily manufactured by ensuring uniform cooling capacity within the mold during the continuous casting process of an aluminum alloy billet with a large amount of alloying elements.

[0010] In addition, sound billets can be manufactured by controlling cooling deformation through the blocking of the cooling water. Brief explanation of the drawing

[0011] FIG. 1 illustrates an aluminum alloy billet continuous casting apparatus according to one embodiment. Figure 2 shows the results of observing the cross-section of a billet according to the amount of cooling water. Figure 3 is the result of comparing the cross-sections of a billet manufactured by blocking the cooling water with a cooling water supply blocking part of an aluminum alloy billet continuous casting device according to one embodiment and a billet manufactured without blocking the cooling water. FIGS. 4 and FIGS. 5 illustrate an aluminum alloy billet casting method according to one embodiment. Specific details for implementing the invention

[0012] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0013] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0014] When it is stated that one part is "on" or "on" another part, it may be directly on or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly on" another part, no other part is interposed in between.

[0015] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0016] FIG. 1 illustrates an aluminum alloy billet continuous casting apparatus according to one embodiment.

[0017] Referring to FIG. 1, an aluminum alloy billet continuous casting apparatus according to one embodiment may include a cooling water inlet provided on one side of a mold; a cooling water channel formed in a jacket shape inside the mold; and a cooling water outlet connected to the cooling water channel and provided at the bottom of the mold. The cooling water channel may be formed along a second surface connected to one side of the mold where the cooling water inlet is provided, a third surface connected to the second surface, and a fourth surface connected to the third surface, which penetrates the interior of the mold. That is, it may be formed in a 'U' shape inside a rectangular prism-shaped mold, and the cooling water flowing into the cooling water channel passes through the interior of the mold to uniformly cool the mold.

[0018] The cooling of the molten aluminum alloy within the mold relies solely on indirect cooling by the mold cooled by cooling water. In other words, the indirect cooling of the molten metal according to the continuous casting apparatus proposed in this invention involves supplying cooling water at a constant temperature to the mold, and the mold absorbing heat from the molten metal to solidify it into a specific shape for casting. In a jacket-type mold that directly cools the mold, cooling water is supplied from within the metal—specifically, water supplied from the bottom in a "U" shape—enabling consistent cooling of the mold, and the cooling water is discharged from the bottom of the mold. Thus, the cooling water supplied consistently from the bottom makes it possible to uniformly cool the entire mold in an indirect manner.

[0019] At the cooling water outlet, cooling water that has passed through the cooling water path can be sprayed onto the billet at a predetermined angle. Preferably, the cooling water sprayed from the cooling water outlet can be sprayed at an angle of (30) to (45) degrees in the direction in which the billet is formed. The cooling water outlet provided at the bottom of the mold allows cooling water to be supplied directly and obliquely to the billet from the bottom of the mold to ensure cooling of the unsolidified area inside the aluminum billet and a sound surface.

[0020] An aluminum alloy billet continuous casting apparatus according to one embodiment may further include a cooling water supply blocking unit that controls the supply of cooling water sprayed from a cooling water outlet. The cooling water supply blocking unit may be a shutter that prevents the supply of cooling water after the billet has completely solidified. By installing a shutter to prevent cooling water from being directly supplied to the billet through the bottom of the mold after the billet has completely solidified, the aim is to control cracks generated during the cooling process after solidification. This provides the advantage of easily manufacturing sound aluminum alloy billets without surface or internal cracks.

[0021] Additionally, it may further include an oil supply unit that supplies vegetable oil at a flow rate of 10cc / min to 30cc / mm, and the cooling water inlet may introduce liters of cooling water (30) to (60) at (15) to (25) degrees into the cooling water.

[0022] Meanwhile, by using the aluminum alloy billet continuous casting device according to the present invention, billets can be cast at a rate of 50 mm / min to 80 mm / min per minute, and solid solution aluminum alloy billets with a total solute alloy content of 7% or more can be manufactured to have a sound surface without internal cracks.

[0023] FIGS. 4 and FIGS. 5 illustrate an aluminum alloy billet casting method according to one embodiment. A method for casting an aluminum alloy billet according to one embodiment may include the steps of: supplying a solid solution aluminum alloy raw material, having a total solute alloy content of 7% or more, to a heated crucible ((100)); raising the temperature of the solid solution aluminum alloy raw material supplied to the crucible to (700)°C or (800)°C ((200)); bubbling gas ((300)); injecting the bubbling molten alloy into a mold ((400)); introducing cooling water into the mold to indirectly cool the molten alloy ((500)); and spraying the cooling water onto a billet formed by cooling while discharging it to the bottom of the mold ((600)). Preferably, the cooling water may pass through a jacket-shaped cooling water channel inside the mold to uniformly cool the entire mold ((500)'), and the cooling water is sprayed onto the billet at an angle of (30)°C or (34)°C when discharged to the bottom of the mold ((600)'), and when the billet is completely solidified, the cooling water The discharge of cooling water to the bottom of the mold can be blocked by the supply blocking unit ((700).

[0024] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention, and the present invention is defined only by the scope of the claims set forth below.

[0025] Example 1

[0026] Aluminum alloy in the form of an ingot or scrap, with a total of approximately 7% Zn and Mg components, approximately 2% Cu, and a total solute alloy amount of approximately 10%, was loaded into a crucible heated by an electric resistance heating method and heated to approximately 750°C. After securing a certain amount of molten metal, a rotor capable of applying gas bubbles was loaded into the molten metal, and Ar gas was bubbled for (15) minutes to degas it. Afterward, the sound molten metal maintained at approximately 710°C was injected into the mold of Fig. 1 through a filter box and a runner. The molten metal supplied to the mold while maintaining a constant water level in the runner is supplied to the mold while the molten metal surface is maintained at a constant temperature. The aluminum molten metal injected into the mold maintained a constant water level within the mold at approximately (690) to (700°C). Cooling water (30) to (60) liters at approximately (20°C) was supplied to the mold while controlling the amount, and Vegetable oil was supplied to the mold in a quantity of 30cc (10) per minute, and billets of 80mm (50) per minute were cast.

[0027] Experimental Example (1) - Comparison of cross-sections of solid solution-containing aluminum billets according to the control of cooling water volume

[0028] In order for the billet in the mold to be continuously cast soundly, the process of solidifying the molten metal is important. In particular, the solidification of the molten metal depends on the cooling capacity of the mold. An aluminum alloy with a total of 7% Zn and Mg components and 2% Cu was manufactured using a conventional aluminum alloy billet continuous casting device with varying amounts of cooling water, and the results of observing the cross-section of the manufactured billet are shown in Figure 2.

[0029] Figure 2 shows the results of observing the cross-section of a billet according to the amount of cooling water. (a) is a cross-section of an aluminum alloy billet manufactured by supplying 50 to 70 L of cooling water at 25 degrees per minute, (b) is a cross-section of an aluminum alloy billet manufactured by supplying 40 to 60 L of cooling water at 25 degrees per minute, and (c) is a cross-section of an aluminum alloy billet manufactured by supplying 30 to 50 L of cooling water at 25 degrees per minute.

[0030] As shown in Fig. 2, when there is a relatively large amount of cooling water (a), a large crack can be observed in the center of the billet. However, if the amount of cooling water is controlled (b), it can be seen that the crack in the center is reduced as shown in (c). At the same time, it can be seen that during the casting process, cracks can be controlled by controlling the cooling capacity of the mold part with a minimum amount of cooling water and by reducing the temperature difference between the molten metal in contact with the mold and the center of the mold. In order to achieve this effect, the present invention supplies cooling water to the internal cooling water of a jacket-type mold to uniformly cool the mold, thereby increasing surface integrity and minimizing cracks.

[0031] Experimental Example (2) - Comparison of billet cross-sections depending on whether cooling water supply is cut off

[0032] In Experimental Example (1), 30 to 50 L of cooling water at a temperature of 25 degrees per minute was supplied, and after casting, that is, solidification inside the mold, the cooling water was supplied to the billet for additional cooling, whereas in (b), the additional cooling water was cut off to produce an aluminum alloy billet (b).

[0033] FIG. 3 is the result of comparing the cross-sections of a billet manufactured by blocking the cooling water supply using a cooling water supply blocking unit of an aluminum alloy billet continuous casting device according to one embodiment with a billet manufactured without blocking the cooling water. As shown in FIG. 3, when the amount of cooling water is continuously supplied after continuous casting, the occurrence of a crack (a) in the center is observed as shown in FIG. 3. On the other hand, when the cooling water is blocked, cracks do not occur (b). That is, after continuous casting, the billet is generally continuously cooled by the cooling water supplied from the mold, and it can be seen that there is difficulty in suppressing deformation during the cooling process of the billet. In order to control this, the present invention provides a cooling water supply blocking unit that blocks the supply of cooling water after continuous casting at the bottom of the mold in FIG. 1 to suppress thermal deformation caused by rapid cooling and secure a crack-free continuous casting material (b).

[0034] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

Claim 1 A continuous casting apparatus for aluminum alloy billets comprising: a cooling water inlet provided on one side of a mold; a cooling water channel formed in a jacket shape inside the mold; a cooling water outlet connected to the cooling water channel and provided at the bottom of the mold; and a cooling water supply blocking unit for controlling the supply of cooling water sprayed from the cooling water outlet. Claim 2 In claim 1, the aluminum alloy billet continuous casting apparatus is formed along a second surface connected to one surface of the mold where the cooling water inlet is provided, a third surface connected to the second surface, and a fourth surface connected to the third surface, wherein the cooling water channel is provided penetrating the interior of the mold. Claim 3 In claim 1, the cooling water flowing into the cooling water channel passes through the inside of the mold to uniformly cool the mold, an aluminum alloy billet continuous casting apparatus. Claim 4 In claim 1, the cooling water outlet is an aluminum alloy billet continuous casting apparatus in which cooling water passing through the cooling water path is sprayed onto the billet at a predetermined angle. Claim 5 In paragraph 4, the cooling water sprayed from the cooling water outlet is sprayed in the direction (30) to (45) degrees in the aluminum alloy billet continuous casting apparatus in which the billet is generated. Claim 6 delete Claim 7 In claim 1, the cooling water supply blocking part is a shutter that prevents cooling water from being supplied after the billet has completely solidified, in an aluminum alloy billet continuous casting apparatus. Claim 8 An aluminum alloy billet continuous casting apparatus according to claim 1, further comprising an oil supply unit that supplies vegetable oil at a flow rate of 10cc / min to 30cc / mm. Claim 9 In claim 1, the above cooling water inlet is an aluminum alloy billet continuous casting apparatus that introduces (30) to (60) liters of cooling water (15) to (25) degrees into the cooling water channel. Claim 10 In claim 1, an aluminum alloy billet continuous casting apparatus that casts billets at a rate of 50 mm / min to 80 mm / min. Claim 11 In claim 1, the aluminum alloy billet continuous casting apparatus is an aluminum alloy billet continuous casting apparatus for producing a solid solution aluminum alloy billet having a total solute alloy content of 7% or more. Claim 12 A method for casting an aluminum alloy billet comprising the steps of: supplying a solid solution aluminum alloy raw material having a total solute alloy content of 7% or more to a heated crucible; raising the temperature of the solid solution aluminum alloy raw material supplied to the crucible to (700) degrees or (800) degrees; bubbling gas; injecting the bubbling molten alloy into a mold; introducing cooling water into the mold to indirectly cool the molten alloy; and spraying the cooling water onto a billet formed by cooling while discharging it to the bottom of the mold, wherein when the billet is completely solidified, the discharge of cooling water to the bottom of the mold is blocked by a cooling water supply cutoff part. Claim 13 In claim 12, the method for casting an aluminum alloy billet involves the cooling water passing through a jacket-shaped cooling water channel inside the mold to uniformly cool the entire mold. Claim 14 In claim 12, the above cooling water is sprayed onto the billet at an angle of (30) to (34) degrees when discharged from the bottom of the mold in an aluminum alloy billet casting method. Claim 15 delete

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