Horizontal continuous casting equipment, method for manufacturing aluminum alloy cast rods

Abstract

To provide a horizontal continuous casting apparatus which prevents occurrence of seizure from occurring in an ingot even if a large amount of lubrication oil is supplied, and can reduce ingot defects, and an aluminum alloy cast rod manufacturing method.SOLUTION: A horizontal continuous casting apparatus 10, that manufactures an aluminum alloy cast rod B in a hollow casting mold 12, of which a central axis of a hollow part 21 is located along a horizontal direction, from a molten aluminum alloy M in a molten metal reception part 11, has: a fluid supply pipe 22 which supplies a lubrication fluid into the hollow part of the casting mold; and a cooling water cavity 24 which is formed on an outer side with respect to an inner peripheral surface 21a of the hollow part of the casting mold, and accommodates cooling water W for cooling the inner peripheral surface. The inner peripheral surface and an inner bottom surface of the cooling water cavity facing the inner peripheral surface are parallel to each other, and a cooling wall part 27 of the casting mold between the inner peripheral surface and the inner bottom surface is so formed that a heat flux per unit area toward cooling water from the molten aluminum alloy becomes 10×105 W / m2 or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a horizontal continuous casting apparatus that supplies molten alloy to the hollow portion of a horizontally arranged mold and continuously casts aluminum alloy cast rods, and to a method for producing aluminum alloy cast rods using the same. [Background technology]

[0002] For example, in recent transportation equipment, aluminum alloy parts have been increasingly adopted due to the demand for weight reduction. Such aluminum alloy parts are obtained by cutting aluminum alloy bars to a predetermined length to prepare forging materials, and then forging the forging materials into parts. The aluminum alloy bars are manufactured by, for example, performing plastic working and heat treatment on materials produced by horizontal continuous casting.

[0003] Horizontal continuous casting generally produces long cylindrical, rectangular, or hollow ingots from molten metal through the following process: The molten metal enters a molten metal receiver, passes through a refractory molten metal passage, and then enters the hollow portion of a horizontally installed, hollow cylindrical mold, where it is forcibly cooled to form a solidified shell on the outer surface of the molten metal. A coolant such as water is then sprayed directly onto the ingot as it is withdrawn from the mold, and the solidification of the metal progresses to the interior of the ingot, resulting in the continuous withdrawal of a rod-shaped ingot.

[0004] In such horizontal continuous casting, lubricating oil is injected from a supply pipe onto the inner peripheral wall of the inlet side (one end side) of the mold to prevent the molten metal from seizing onto the inner peripheral wall of the hollow part of the mold (see, for example, Patent Document 1). In horizontal continuous casting, for alloys that are particularly prone to seizing, such as aluminum alloys containing Mg, seizing is prevented by increasing the amount of lubricating oil supplied from the supply pipe. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-170009 Summary of the Invention [Problem to be solved by the invention]

[0006] In horizontal continuous casting, the difference in gravity acting on the top and bottom surfaces of the ingot pushes the lubricating oil from the lower to the upper wall of the inner circumferential wall of the mold. Furthermore, decomposition gases generated by heating the lubricating oil also rise to the upper wall. Therefore, if a large amount of lubricating oil is supplied to prevent seizure, the excess vaporized lubricating oil gas will accumulate on the upper wall of the mold, preventing heat transfer between the molten metal and the mold.

[0007] This results in differences in the cooling conditions between the top and bottom of the ingot, resulting in a larger difference in the alloy structure between the top and bottom of the ingot. If the difference in alloy structure between the top and bottom becomes large, there is a concern that the difference in mechanical strength between the top and bottom will be greater than in an ingot with a uniform alloy structure. Furthermore, there is a risk that the large amount of accumulated lubricating oil gas will come into contact with the molten metal and react, and reaction products, such as carbides, may be caught in the surface of the ingot. In such cases, there is a problem that the cutting allowance on the surface of the ingot increases or the ingot is likely to become unusable as a product.

[0008] The present invention has been made in view of the above, and aims to provide a horizontal continuous casting apparatus that can prevent seizure of the ingot even when a large amount of lubricating oil is supplied, thereby reducing ingot defects, and a method for producing an aluminum alloy cast rod using the same. [Means for solving the problem]

[0009] To solve the above problem, the inventors investigated the cause of the need for a large amount of lubricating oil by measuring the temperature of the inner circumferential surface of the hollow portion of the mold, where the molten alloy is in contact, in the region facing the inner bottom surface of the cooling water cavity. As a result, it was confirmed that the wall temperature of this region was 180°C to 200°C, and when the amount of lubricating oil was reduced in this temperature range, seizure occurred in the ingot where the molten alloy solidified. Therefore, the inventors discovered that seizure can be prevented by setting the heat flux value of this region within a specific range to ensure appropriate heat exchange between the inner circumferential surface of the hollow portion of the mold and the inner bottom surface of the cooling water cavity.

[0010] The present invention has been made based on the above-mentioned findings, and provides a horizontal continuous casting apparatus for producing an aluminum alloy cast rod by supplying molten aluminum alloy from a molten metal receptacle into a hollow portion of a hollow mold disposed so that the central axis of the hollow portion is horizontal, the horizontal continuous casting apparatus comprising: a fluid supply pipe disposed at the one end of the mold for supplying a lubricating fluid to the hollow portion of the mold; and a cooling water cavity formed outside an inner peripheral surface of the hollow portion of the mold for containing cooling water for cooling the inner peripheral surface, the cooling water cavity having a lubricating fluid supply pipe disposed at the one end of the mold for supplying a lubricating fluid to the hollow portion of the mold; 、 the cooling water cavity The cooling water is in contact with the lower side of the The inner peripheral surface and the inner bottom surface are parallel to each other, and the cooling wall portion of the mold between the inner peripheral surface and the inner bottom surface has a heat flux value per unit area from the molten aluminum alloy toward the cooling water of 10×10 5 W / m 2 The present invention is characterized in that the above-mentioned is formed.

[0011] According to the present invention, the heat flux value per unit area of ​​the cooling wall of the mold, where the inner bottom surface of the cooling water cavity faces the inner peripheral surface of the hollow portion of the mold, is 10×10 5 W / m 2 By achieving the above, even when casting an aluminum alloy having a composition that is prone to seizure during casting, it is possible to reliably suppress the generation of lubricant reaction products and produce a high-quality aluminum alloy cast rod.

[0012] In the present invention, the heat flux value is 50×10 5 W / m 2 It may be the following:

[0013] In the present invention, the thickness of the cooling wall portion of the mold may be in the range of 0.5 mm or more and 3.0 mm or less.

[0014] In the present invention, a cooling water injection passage may be provided to connect the cooling water cavity with the hollow portion of the mold.

[0015] In the present invention, a heat insulating member may be disposed between the molten metal receiver and one end of the mold.

[0016] In the present invention, the molten aluminum alloy may have a magnesium content of 0.5 mass % or more.

[0017] In the present invention, the components of the molten aluminum alloy may include Si (content of 0.05 to 1.3 mass%), Fe (content of 0.1 to 0.7 mass%), Cu (content of 0.1 to 2.5 mass%), Mn (content of 0.05 to 1.1 mass%), Mg (content of 0.8 to 3.5 mass%), Cr (content of 0.04 to 0.4 mass%), and Zn (content of 0.05 to 8.0 mass%).

[0018] The present invention provides a method for producing a cast aluminum alloy rod using the horizontal continuous casting apparatus described above, wherein the molten alloy is continuously supplied from one end of the mold to the hollow portion, and cooling water is supplied to the cooling water cavity, so that the heat flux value per unit area in the cooling wall is 10×10 5 W / m 2 The molten alloy is cooled and solidified under the above conditions to produce a cast aluminum alloy rod. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a horizontal continuous casting apparatus that can prevent seizure of the ingot even when a large amount of lubricating oil is supplied, thereby reducing ingot defects, and a method for producing an aluminum alloy cast rod using the same. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view of a main portion of an example of a horizontal continuous casting apparatus according to the present invention, showing the vicinity of a mold. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a main part in the vicinity of the cooling water cavity in FIG. 1. [Figure 3] 4 is an explanatory diagram illustrating the heat flux of the cooling wall portion according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] A horizontal continuous casting apparatus and a method for producing an aluminum alloy cast rod according to one embodiment of the present invention will be described below with reference to the drawings. The following embodiment is specifically described to provide a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. Furthermore, the drawings used in the following description may show essential parts enlarged for the sake of clarity, and the dimensional proportions of the components may not necessarily be the same as those in reality.

[0022] First, an example of an aluminum alloy cast rod produced by the horizontal continuous casting apparatus of this embodiment will be described. The aluminum alloy cast rod is produced by horizontal continuous casting using a hollow cylindrical mold equipped with a cooling means and held so that its central axis is approximately horizontal (approximately horizontal means in the lateral direction), and can have a diameter in the range of 10 mm to 100 mm, for example.

[0023] Although aluminum alloy cast rods can be produced with diameters outside this range, it is preferable to set the diameter within the range of 10 mm to 100 mm in order to industrially reduce the size and cost of equipment for subsequent plastic processing steps, such as forging, roll forging, drawing, rolling, and impact processing. Casting with a different diameter can be achieved by replacing the mold with a removable cylindrical mold having an inner diameter corresponding to the diameter, and then adjusting the molten metal temperature and casting speed accordingly. The amounts of cooling water and lubricating oil can also be adjusted as needed.

[0024] Such an aluminum alloy cast rod can be used, for example, as a material for subsequent plastic working processes such as forging, roll forging, drawing, rolling, and impact working, or as a material for machining processes such as burr machining and drilling.

[0025] Next, a horizontal continuous casting apparatus according to one embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing an example of the vicinity of a mold in a horizontal continuous casting apparatus according to the present invention. The horizontal continuous casting apparatus 10 of this embodiment has a molten metal receiving portion (tundish) 11, a hollow cylindrical mold 12, and a refractory plate-like body (insulating member) 13 arranged between one end side 12a of the mold 12 and the molten metal receiving portion 11.

[0026] The molten metal receiving section 11 is composed of a molten metal inlet section 11a that receives molten aluminum alloy (hereinafter referred to as molten alloy) M that has been adjusted to a specified alloy composition by an external melting furnace or the like, a molten metal holding section 11b, and an outlet section 11c that flows into the hollow section 21 of the mold 12. The molten metal receiving section 11 maintains the upper liquid level of the molten alloy M at a position higher than the upper surface of the hollow section 21 of the mold 12, and in the case of multiple casting, stably distributes the molten alloy M to each mold 12.

[0027] The molten alloy M held in the molten metal holding portion 11b in the molten metal receiving portion 11 is poured into the hollow portion 21 of the mold 12 through a pouring passage 13a provided in the refractory plate 13. The molten alloy M supplied into the hollow portion 21 is then cooled and solidified by a cooling device 23 (described later) and drawn out from the other end 12b of the mold 12 as a solidified ingot, an aluminum alloy cast rod B.

[0028] A drawing drive device (not shown) for drawing the cast aluminum alloy rod B at a constant speed may be installed at the other end 12b of the mold 12. It is also preferable that a synchronized cutting machine (not shown) for cutting the continuously drawn aluminum alloy rod B to a desired length be installed.

[0029] The refractory plate 13 is a member that blocks heat transfer between the molten metal receiver 11 and the mold 12, and may be made of materials such as calcium silicate, alumina, silica, a mixture of alumina and silica, silicon nitride, silicon carbide, graphite, etc. Such a refractory plate 13 may also be made up of multiple layers made of different materials.

[0030] In this embodiment, the mold 12 is a hollow cylindrical member made of, for example, one or a combination of two or more materials selected from aluminum, copper, or alloys thereof. The materials for the mold 12 may be selected from the optimal combination in terms of thermal conductivity, heat resistance, and mechanical strength.

[0031] The hollow portion 21 of the mold 12 is formed to have a circular cross section so that the aluminum alloy cast rod B to be cast will be cylindrical, and the mold 12 is held so that the mold central axis (central axis) C passing through the center of this hollow portion 21 is aligned approximately horizontally.

[0032] The inner peripheral surface 21a of the hollow portion 21 of the mold 12 is formed at an elevation angle of 0 to 3 degrees (more preferably 0 to 1 degree) with respect to the mold center axis C toward the drawing direction of the aluminum alloy cast bar B. That is, the inner peripheral surface 21a is configured in a tapered shape that opens out like a cone toward the drawing direction. The angle of this taper is the elevation angle.

[0033] If the elevation angle is less than 0 degrees, the aluminum alloy cast rod B encounters resistance at the other end 12b, which is the mold outlet, when it is drawn out of the mold 12, making casting difficult. On the other hand, if the elevation angle exceeds 3 degrees, the inner peripheral surface 21a will not make sufficient contact with the molten alloy M, reducing the heat transfer effect from the molten alloy M and its solidified shell to the mold 12, which may result in insufficient solidification. This is undesirable because it increases the likelihood of casting problems, such as the formation of a remelted skin on the surface of the aluminum alloy cast rod B or the ejection of unsolidified molten alloy M from the end of the aluminum alloy cast rod B.

[0034] The cross-sectional shape of the hollow portion 21 of the mold 12 (the planar shape when the hollow portion 21 of the mold 12 is viewed from the other end side 21b) may be selected to match the shape of the aluminum alloy cast rod to be cast, such as a triangular or rectangular cross-sectional shape, a polygonal, semicircular, elliptical, or an irregular cross-sectional shape that does not have an axis or plane of symmetry, in addition to the circular shape of this embodiment.

[0035] A fluid supply pipe 22 is disposed at one end 12a of the mold 12 to supply a lubricating fluid into the hollow portion 21 of the mold 12. The lubricating fluid supplied from the fluid supply pipe 22 can be one or more lubricating fluids selected from a gas lubricant and a liquid lubricant. When supplying both a gas lubricant and a liquid lubricant, it is preferable to provide separate fluid supply pipes for each. The lubricating fluid supplied under pressure from the fluid supply pipe 22 is supplied into the hollow portion 21 of the mold 12 through an annular lubricant supply port 22a.

[0036] In this embodiment, the lubricating fluid is supplied under pressure from the lubricant supply port 22a to the inner circumferential surface 21a of the mold 12. The liquid lubricant may be heated to decompose into a gas and then supplied to the inner circumferential surface 21a of the mold 12. Alternatively, a porous material may be disposed in the lubricant supply port 22a, and the lubricating fluid may be allowed to seep out onto the inner circumferential surface 21a of the mold 12 through the porous material.

[0037] A cooling device 23, which is a cooling means for cooling and solidifying the molten alloy M, is formed inside the mold 12. The cooling device 23 of this embodiment has a cooling water cavity 24 that accommodates cooling water W for cooling the inner circumferential surface 21 a of the hollow portion 21 of the mold 12, and a cooling water injection passage 25 that connects the cooling water cavity 24 and the hollow portion 21 of the mold 12.

[0038] The cooling water cavity 24 is formed in the mold 12 outside the inner peripheral surface 21a of the hollow portion 21 and has an annular shape so as to surround the hollow portion 21, and cooling water W is supplied to the cavity 24 via a cooling water supply pipe . The inner surface 21a of the mold 12 is cooled by the cooling water W contained in the cooling water cavity 24, which removes heat from the molten alloy M filling the hollow portion 21 of the mold 12 from the surface in contact with the inner surface 21a of the mold 12, forming a solidified shell on the surface of the molten alloy M.

[0039] The cooling water jetting passages 25 spray cooling water from shower openings 25a facing the hollow portion 21 directly onto the cast aluminum alloy rod B at the other end 12b of the mold 12, thereby cooling the cast aluminum alloy rod B. The vertical cross-sectional shape of the cooling water jetting passages 25 may be, for example, semicircular, pear-shaped, or horseshoe-shaped, in addition to the circular shape of this embodiment.

[0040] In this embodiment, the cooling water W supplied through the cooling water supply pipe 26 is first stored in the cooling water cavity 24 to cool the inner peripheral surface 21a of the hollow portion 21 of the mold 12, and then the cooling water W in the cooling water cavity 24 is sprayed toward the aluminum alloy cast bar B through the cooling water spray passages 25. However, these may also be configured to be supplied by separate cooling water supply pipes.

[0041] The length from the position where the extension of the central axis of the shower opening 25a of the cooling water injection passage 25 hits the surface of the cast aluminum alloy cast rod B to the contact surface between the mold 12 and the refractory plate 13 is called the effective mold length L, and this effective mold length L is preferably 10 mm to 40 mm, for example. If this effective mold length L is less than 10 mm, a satisfactory coating cannot be formed, making casting impossible. If it exceeds 40 mm, forced cooling is ineffective, solidification by the mold wall becomes dominant, and contact resistance between the mold 12 and the molten alloy M or the aluminum alloy cast rod B increases, resulting in unstable casting, such as cracks on the casting surface or tearing inside the mold.

[0042] It is preferable that the supply of cooling water to the cooling water cavity 24 and the spray of cooling water from the shower opening 25a of the cooling water spray passage 25 can be controlled by control signals from a control device (not shown).

[0043] The cooling water cavity 24 is formed so that the inner bottom surface 24a closer to the hollow portion 21 of the mold 12 is parallel to the inner peripheral surface 21a of the hollow portion 21 of the mold 12. Note that "parallel" here also includes the case where the inner bottom surface 24a of the cooling water cavity 24 is formed at an elevation angle of 0 to 3 degrees with respect to the inner peripheral surface 21a of the hollow portion 21 of the mold 12, that is, the case where the inner bottom surface 24a is inclined at an angle of more than 0 degrees up to 3 degrees with respect to the inner peripheral surface 21a.

[0044] As shown in FIG. 2, the cooling wall portion 27 of the mold 12, which is the portion where the inner bottom surface 24a of the cooling water cavity 24 faces the inner peripheral surface 21a of the hollow portion 21 of the mold 12, has a heat flux value per unit area of ​​10×10 5 W / m 2 That's it, 50 x 10 5 W / m 2 It is formed so as to fall within the following ranges.

[0045] The mold 12 may be formed so that the thickness t of the cooling wall portion 27 of the mold 12, i.e., the distance between the inner bottom surface 24a of the cooling water cavity 24 and the inner peripheral surface 21a of the hollow portion 21 of the mold 12, is, for example, 0.5 mm to 3.0 mm, and preferably 0.5 mm to 2.5 mm. The material for forming the mold 12 may be selected so that the thermal conductivity of at least the cooling wall portion 27 of the mold 12 is in the range of 100 W / m K to 400 W / m K.

[0046] The operation of the horizontal continuous casting apparatus of the present invention will be described. In Fig. 1, molten alloy M in molten metal receptacle 11 is supplied through refractory plate 13 to one end 12a of mold 12, which is held so that its central axis C is substantially horizontal, and is forcedly cooled at the other end 12b of mold 12 to form cast aluminum alloy rod B. Cast aluminum alloy rod B is withdrawn at a constant speed by a withdrawal drive device (not shown) installed near the other end 12b of mold 12, and is thus continuously cast into a long cast aluminum alloy rod B. The withdrawn cast aluminum alloy rod B is then cut to a desired length, for example, by a synchronized shearing machine (not shown).

[0047] The composition of the molten alloy M of the aluminum alloy stored in the molten metal receiver 11 includes, for example, Si (content 0.05 to 1.3% by mass), Fe (content 0.10 to 0.70% by mass), Cu (content 0.1 to 2.5% by mass), Mn (content 0.05 to 1.1% by mass), Mg (content 0.5 to 3.5% by mass), Cr (content 0.04 to 0.4% by mass), and Zn (content 0.05 to 8.0% by mass or less). The Mg content is preferably 0.8 to 3.5% by mass.

[0048] In addition, for example, Si (content 0.05 to 1.3 mass%), Fe (content 0.1 to 0.7 mass%), Cu (content 0.1 to 2.5 mass%), Mn (content 0.05 to 1.1 mass%), Mg (content 0.5 to 3.5 mass%), Cr (content 0.04 to 0.4 mass%), and and Zn (content of 0.05 to 8 mass %). The content of Mg is preferably 0.8 to 3.5 mass %.

[0049] The composition ratio of the cast aluminum alloy rod B can be confirmed, for example, by a method using a photoelectric photometric emission spectrophotometer as described in JIS H 1305 (eg, PDA-5500 manufactured by Shimadzu Corporation, Japan).

[0050] The difference in height between the liquid level of the molten alloy M stored in the molten metal receiver 11 and the upper inner circumferential surface 21a of the mold 12 is preferably 0 mm to 250 mm (more preferably 50 mm to 170 mm). By setting the difference in height within this range, the pressure of the molten alloy M supplied into the mold 12 and the lubricating oil and the gas produced by vaporizing the lubricating oil are suitably balanced, resulting in stable castability.

[0051] The liquid lubricant may be a vegetable oil, such as rapeseed oil, castor oil, or salad oil, which are preferred because they have little adverse effect on the environment.

[0052] The lubricating oil supply rate is preferably 0.05 mL / min to 5 mL / min (more preferably 0.1 mL / min to 1 mL / min). If the supply rate is too low, the molten alloy of the aluminum alloy cast rod B may not solidify and leak from the mold due to insufficient lubrication. If the supply rate is too high, the excess may get mixed into the aluminum alloy cast rod B and cause internal defects.

[0053] The casting speed, which is the speed at which the aluminum alloy cast rod B is withdrawn from the mold 12, is preferably 200 mm / min to 1500 mm / min (more preferably 400 mm / min to 1000 mm / min), because a casting speed within this range results in a uniform and fine network structure of crystals formed by casting, which increases the resistance of the aluminum matrix to deformation at high temperatures and improves its high-temperature mechanical strength.

[0054] The amount of cooling water sprayed from the shower openings 25a of the cooling water spray passages 25 is preferably 10 L / min to 50 L / min (more preferably 25 L / min to 40 L / min) per mold. If the amount of cooling water is less than this, the molten alloy may not solidify and leak from the mold. Also, the surface of the cast aluminum alloy cast bar B may remelt, forming a non-uniform structure that may remain as internal defects. On the other hand, if the amount of cooling water is greater than this range, the mold 12 may lose too much heat, causing it to solidify prematurely.

[0055] The average temperature of the molten alloy M flowing from the molten metal receiver 11 into the mold 12 is preferably, for example, 650°C to 750°C (more preferably 680°C to 720°C). If the temperature of the molten alloy M is too low, coarse crystals will form in the mold 12 or before that, and will be incorporated as internal defects into the cast aluminum alloy bar B. On the other hand, if the temperature of the molten alloy M is too high, a large amount of hydrogen gas will be easily incorporated into the molten alloy 255, which will be incorporated as porosity in the cast aluminum alloy bar B, potentially causing internal cavities.

[0056] In the present embodiment, in the cooling wall portion 27 of the mold 12, the heat flux value per unit area from the molten alloy M in the hollow portion 21 to the cooling water W in the cooling water cavity 24 is 10×10 5 W / m 2 That's it, 50 x 10 5 W / m 2 By setting the temperature within the following range, it is possible to prevent the aluminum alloy cast rod B from seizing.

[0057] The cooling wall portion 27 of the mold 12 receives heat by extracting heat from the molten alloy M, and performs heat exchange by cooling this heat with the cooling water W contained in the cooling water cavity 24. Regarding the state of this heat exchange, we focused on the heat flux per unit area, as shown in the explanatory diagram in Figure 3. The heat flux per unit area is expressed by Fourier's law as follows: Q = -k × ((T1-T2 / L) (1) Q: Heat flux k: Thermal conductivity (W / m K) of the portion through which heat passes (in this embodiment, the cooling wall portion 27 of the mold 12) T1: low temperature of the location where heat passes (in this embodiment, the inner bottom surface 24a of the cooling water cavity 24) T2: High temperature side temperature of the portion through which heat passes (in this embodiment, the inner peripheral surface 21a of the hollow portion 21 of the mold 12) L: Length (mm) of the section where heat passes through (in this embodiment, the thickness t of the cooling wall portion 27 of the mold 12)

[0058] Good results were obtained even when the amount of lubricant was reduced during casting. Based on the mold material, thickness, and temperature measurement data, the heat flux value per unit area was 10 × 10 5 W / m 2 By configuring the cooling wall portion 27 of the mold 12 so that the heat flux value per unit area is 50×10 or more, it is possible to prevent seizure of the cast aluminum alloy rod B. 5 W / m 2 It is preferable to do the following:

[0059] To achieve this heat flux range for the cooling wall 27 of the mold 12, the mold 12 should be formed so that the thickness t of the cooling wall 27 of the mold 12 is, for example, in the range of 0.5 mm to 3.0 mm. Also, the thermal conductivity of at least the cooling wall 27 of the mold 12 should be in the range of 100 W / m K to 400 W / m K.

[0060] In a method for producing an aluminum alloy cast rod according to one embodiment of the present invention, the molten alloy M stored in the molten metal receptacle 11 is continuously supplied from one end 12a of the mold 12 into the hollow portion 21 using the horizontal continuous casting apparatus described above. In addition, cooling water W is supplied to the cooling water cavity 24, and a lubricating fluid, such as lubricating oil, is supplied from the fluid supply pipe 22.

[0061] The molten alloy M supplied into the hollow portion 21 is cooled to a temperature at which the heat flux per unit area of ​​the cooling wall portion 27 is 10×10 5 W / m 2The aluminum alloy is cooled and solidified under the above conditions to cast the cast aluminum alloy rod B. During casting of the cast aluminum alloy rod B, it is preferable to set the wall surface temperature of the cooling wall portion 27 of the mold 12, which is cooled by the cooling water W, to 100°C or less.

[0062] The aluminum alloy cast rod B thus obtained has a heat flux value per unit area in the cooling wall portion 27 of 10×10 5 W / m 2 Cooling and solidification under the above conditions suppresses the adhesion of reaction products, such as carbides, that occur when the lubricating oil gas comes into contact with the molten alloy M. This eliminates the need to remove carbides and other particles from the surface of the aluminum alloy cast rod B by cutting, and allows the aluminum alloy cast rod B to be produced with a high yield.

[0063] As described above, according to the horizontal continuous casting apparatus of this embodiment and the method for producing an aluminum alloy cast rod using the same, the heat flux value per unit area of ​​the cooling wall portion 27 of the mold 12, which is the portion where the inner bottom surface 24a of the cooling water cavity 24 faces the inner circumferential surface 21a of the hollow portion 21 of the mold 12, is 10×10 5 W / m 2 By achieving the above, even when casting an aluminum alloy that is prone to seizure during casting, such as an aluminum alloy containing 0.5 mass % or more (preferably 0.8 mass % or more) of magnesium, it is possible to reliably suppress the generation of lubricant reaction products and produce a high-quality aluminum alloy cast bar B.

[0064] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Example]

[0065] The effects of the present invention were verified. For the verification, a horizontal continuous casting apparatus 10 having the structure shown in Fig. 1 was used to calculate the heat flux per unit area of ​​the cooling wall 27 under the conditions of Examples 1 to 4, in which the constituent material of the mold 12 and the thickness of the cooling wall 27 were varied, and Comparative Examples 1 and 2, and the presence or absence of seizure in the cast aluminum alloy cast rod B was visually confirmed. The molten alloy used was an aluminum alloy containing 0.5 mass % magnesium. The results of this verification are shown in Table 1.

[0066] [Table 1]

[0067] According to the results shown in Table 1, when the thickness of the cooling wall portion 27 is set to 0.5 mm to 2 mm, the heat flux per unit area of ​​the cooling wall portion 27 is set to 10×10 5 W / m 2 It was confirmed that by carrying out the above steps, the occurrence of seizure in the cast aluminum alloy rod B can be prevented. [Explanation of symbols]

[0068] 10...Horizontal continuous casting equipment 11...Tundish 12...Mold 13... Refractory plate (heat insulating member) 21...Hollow part 21a...Inner peripheral surface 23…Cooling device 24...Cooling water cavity 24a…Inner bottom surface 25…Cooling water injection passage 26…Cooling water supply pipe 27...Cooling wall B...Aluminum alloy cast rod M...molten alloy W...cooling water

Claims

1. 1. A horizontal continuous casting apparatus for producing an aluminum alloy cast rod by supplying molten aluminum alloy from a molten metal receiver into a hollow portion of a hollow mold arranged so that the central axis of the hollow portion is horizontal, the apparatus comprising: a fluid supply pipe disposed on one end side of the mold and supplying a lubricating fluid to a hollow portion of the mold; a cooling water cavity formed outside the inner peripheral surface of the hollow portion of the mold and configured to accommodate cooling water for cooling the inner peripheral surface; the inner circumferential surface and an inner bottom surface that faces the inner circumferential surface and is in contact with the cooling water on a lower side of the cooling water cavity are parallel to each other, The cooling wall portion of the mold between the inner peripheral surface and the inner bottom surface has a heat flux value per unit area from the molten aluminum alloy toward the cooling water of 10×10 ５ W / m ２ A horizontal continuous casting apparatus characterized by being formed as described above.

2. The heat flux value is 50×10 ５ W / m ２ 2. The horizontal continuous casting apparatus according to claim 1, wherein:

3. 3. The horizontal continuous casting apparatus according to claim 1, wherein the thickness of the cooling wall of the mold is in the range of 0.5 mm to 3.0 mm.

4. 4. The horizontal continuous casting apparatus according to claim 1, further comprising a cooling water injection passage that connects the cooling water cavity with the hollow portion of the mold.

5. 5. The horizontal continuous casting apparatus according to claim 1, wherein a heat insulating member is disposed between the molten metal receiver and one end of the mold.

6. 6. The horizontal continuous casting apparatus according to claim 1, wherein the molten aluminum alloy has a magnesium content of 0.5 mass % or more.

7. 7. The horizontal continuous casting apparatus according to claim 1, wherein the molten aluminum alloy contains Si (content: 0.05 to 1.3% by mass), Fe (content: 0.1 to 0.7% by mass), Cu (content: 0.1 to 2.5% by mass), Mn (content: 0.05 to 1.1% by mass), Mg (content: 0.8 to 3.5% by mass), Cr (content: 0.04 to 0.4% by mass), and Zn (content: 0.05 to 8.0% by mass or less).

8. A method for producing an aluminum alloy cast rod using the horizontal continuous casting apparatus according to any one of claims 1 to 7, comprising the steps of: The molten alloy is continuously supplied from one end of the mold to the hollow portion, and cooling water is supplied to the cooling water cavity, so that the heat flux value per unit area of ​​the cooling wall portion is 10×10 ５ W / m ２ The method for producing a cast aluminum alloy rod comprises cooling and solidifying the molten alloy under the above conditions to produce a cast aluminum alloy rod.

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