Aluminum alloy molten metal treatment device

Abstract

To provide a molten aluminum alloy processing device which can inhibit clogging of a flux in a lance pipe.SOLUTION: A molten aluminum alloy processing device includes a lance pipe 65 having a discharge port for discharging a flux. The lance pipe 65 has: a small diameter pipe 66; and a large diameter pipe 67 into which the small diameter pipe 66 is inserted. The flux flows into the small diameter pipe 66. An inactive gas flows into a space (67a) between the small diameter pipe 66 and the large diameter pipe 67. The flux and the inactive gas are discharged from the discharge port 68a and a gas hole 68b.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to an aluminum alloy molten metal treatment apparatus.

Background Art

[0002] Conventionally, when casting an aluminum alloy, various treatments are performed on the aluminum alloy molten metal (hereinafter referred to as "molten metal"). Patent Document 1 below discloses a molten metal treatment apparatus that performs a treatment of adding a flux to the molten metal and a treatment of blowing a non-oxidizing gas (for example, argon gas, nitrogen gas) into the molten metal. When a flux is added to the molten metal, the added flux reacts with the oxides in the molten metal when it floats in the molten metal. Then, the oxides are separated from the molten metal, and the separated oxides float on the surface of the molten metal. Therefore, the floating oxides can be recovered. That is, the oxides in the molten metal can be removed. Note that a method of adding a flux is disclosed in the impurity removing apparatus described in Patent Document 2 below. In this adding method, a lance pipe is inserted into the molten metal, and the flux is added into the molten metal together with an inert gas from the tip of the inserted lance pipe.

[0003] On the other hand, when a non-oxidizing gas is blown into the molten metal, hydrogen in the molten metal dissolves in the bubbles generated by the blown non-oxidizing gas. Then, the bubbles in which hydrogen has dissolved float on the surface of the molten metal. Therefore, the hydrogen dissolved in the molten metal is released into the atmosphere from the floating bubbles. That is, hydrogen in the molten metal can be removed (degassed). Since oxides and hydrogen in the molten metal can be removed in this way, the quality of the casting cast from the molten metal can be improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the impurity removal device described in Patent Document 2, there was a risk that the flux would melt inside the lance pipe due to the heat from the molten metal. As a result, there was a risk that the melted flux would solidify and clog the inside of the lance pipe. Therefore, there was a need for an aluminum alloy molten metal treatment device that could suppress flux clogging inside the lance pipe. [Means for solving the problem]

[0006] In one feature of this disclosure, an aluminum alloy molten metal processing apparatus is provided with a lance pipe having an outlet for discharging flux. The lance pipe has a small-diameter pipe and a large-diameter pipe through which the small-diameter pipe is inserted. Flux is flowed through the small-diameter pipe. An inert gas is flowed between the small-diameter pipe and the large-diameter pipe. The flux and inert gas are discharged from the outlet. As a result, the inert gas flowing between the small-diameter pipe and the large-diameter pipe shields the heat transferred from the molten metal to the flux. Therefore, the risk of the flux melting inside the lance pipe due to the heat transferred from the molten metal can be suppressed. Thus, the clogging of the flux inside the lance pipe can be suppressed.

[0007] In other features of this disclosure, the lance pipe has a medium-diameter pipe between a small-diameter pipe and a large-diameter pipe. An air layer or refractory material is inserted between the medium-diameter pipe and the small-diameter pipe. An inert gas is flowed between the medium-diameter pipe and the large-diameter pipe. As a result, the air layer or refractory material between the medium-diameter pipe and the small-diameter pipe shields the heat transferred from the molten metal. Therefore, the risk of flux melting inside the lance pipe due to heat transferred from the molten metal can be further suppressed. Hence, the clogging of flux inside the lance pipe can be further suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a front view of an aluminum alloy molten metal processing apparatus according to an embodiment. [Figure 2] Figure 1 is a plan view of the aluminum alloy molten metal processing apparatus. [Figure 3]Figure 1 is a left side view of the aluminum alloy molten metal processing apparatus. [Figure 4] Figure 1 is a bottom view of the aluminum alloy molten metal processing apparatus. [Figure 5] Figure 1 is a bottom view of the impeller. [Figure 6] Figure 5 is a cross-sectional view of the impeller along the line VI-VI. [Figure 7] Figure 5 is a cross-sectional view of the impeller along line VII-VII. [Figure 8] Figure 1 is a longitudinal cross-sectional view of the tip of the lance pipe. [Figure 9] This is an enlarged view illustrating the arrangement of the lance pipes in Figure 1. [Figure 10] Figure 1 is a piping diagram of the aluminum alloy molten metal processing system. [Figure 11] This is a modified example of the lance pipe shown in Figure 8. [Modes for carrying out the invention]

[0009] One embodiment will be described with reference to Figures 1 to 10. As shown in Figure 1, the aluminum alloy molten metal processing apparatus 1 comprises a processing tank 2 and a processing unit 4. The processing tank 2 and the processing unit 4 will be described separately below. In the following description, up and down, front and back, and left and right refer to the directions indicated in each figure.

[0010] As shown in Figures 1-4, the processing tank 2 is, for example, a bottomed circular tank with an inner diameter of about 600 mm, and is installed adjacent to the melting furnace (not shown). Molten aluminum alloy (hereinafter simply referred to as "molten metal 3") melted by the melting furnace is poured into and stored in the processing tank 2. The processing unit 4 comprises a frame body 10, a gas supply rotating mechanism 20, and a flux feeder 70. The frame body 10, the gas supply rotating mechanism 20, and the flux feeder 70 will be described individually below.

[0011] First, referring to FIGS. 1 to 4, the frame body 10 will be described. As shown in FIGS. 1 to 4, the frame body 10 includes four vertical frames 11, an upper horizontal frame 12 having a rectangular frame shape, and a lower horizontal frame 13 having a rectangular frame shape that faces the upper horizontal frame 12 vertically. The upper horizontal frame 12 and the lower horizontal frame 13 are set such that the length in the left-right direction is longer than the length in the front-back direction.

[0012] As shown in FIGS. 1 to 4, the upper surfaces of the four vertical frames 11 are connected to the lower surfaces at the four corners of the upper horizontal frame 12. Similarly, the lower surfaces of the four vertical frames 11 are connected to the upper surfaces at the four corners of the lower horizontal frame 13. By being connected in this way, the frame body 10 is hollow and has an outer shape that is substantially rectangular parallelepiped.

[0013] As shown in FIGS. 1 to 4, handles 14 are respectively attached to the front and rear opposing portions of the upper horizontal frame 12. The handles 14 are attached so as to protrude in a direction away from each other. The handle 14 has a substantially U-shaped form that is easy for an operator (not shown) to grasp. By grasping the handle 14, the operator can easily carry the processing unit 4.

[0014] As shown in FIGS. 1 to 4, mounting plates 15 that bridge each other are attached to the upper surfaces of the front and rear opposing portions of the upper horizontal frame 12 via bolts 16. The mounting plates 15 are attached via a total of four bolts 16, two on each of the front and rear edges. Similarly, reinforcing frames 12a that bridge each other are connected to the front and rear opposing portions of the upper horizontal frame 12. The reinforcing frame 12a can suppress the distortion generated in the upper horizontal frame 12.

[0015] As shown in FIGS. 1 to 4, hooks 17 are respectively attached to both the front and rear edges of the mounting plate 15. The hooks 17 penetrate the mounting plate 15 and are supported by the upper horizontal frame 12. Therefore, by hooking the hanging portion (not shown) of the sling wire connected to a crane or the like on the hook 17, the processing unit 4 can be easily lifted and lowered by a crane or the like.

[0016] As shown in FIGS. 1 to 4, the lower horizontal frame 13 includes four leg members 18 that extend downward to a position where the processing unit 4 can be placed on the upper edge of the processing tank 2. Since the four leg members 18 are support members that support the processing unit 4 itself, they have sufficient strength to withstand the weight of the processing unit 4.

[0017] As shown in FIGS. 1 to 4, reinforcing frames 13a that bridge each other are connected to the front and rear opposing portions of the lower horizontal frame 13. Two reinforcing frames 13a are provided in pairs on the left and right. These two reinforcing frames 13a can suppress the distortion generated in the lower horizontal frame 13. The frame body 10 corresponds to the base described in the claims.

[0018] Next, referring to FIGS. 1 to 3, the gas supply and rotation mechanism 20 will be described. As shown in FIGS. 1 to 3, the gas supply and rotation mechanism 20 is a supply source for blowing an inert gas (such as argon gas, nitrogen gas, etc.) into the molten metal 3 and is also a drive source for stirring the molten metal 3. The gas supply and rotation mechanism 20 has a mechanism body 21 attached to the inside of the frame body 10 by a mounting plate 22. The mounting plate 22 is attached to the upper surfaces of the front and rear opposing portions of the lower horizontal frame 13 so as to bridge the front and rear opposing portions of the lower horizontal frame 13.

[0019] As shown in FIGS. 1 to 3, the mechanism body 21 includes a shaft 23 that extends along the vertical direction. The shaft 23 has a hollow portion 24 with a hollow interior. The hollow portion 24 can pass an inert gas. The shaft 23 is rotatably supported by bearings 25 provided at the upper and lower portions of the mechanism body 21 so as to rotate about an axis with the vertical direction as the axial direction with respect to the mechanism body 21. The proximal end (upper end) of the shaft 23 has a driven pulley 26 that rotates together with the shaft 23. The distal end (lower end) of the shaft 23 has a bracket 27.

[0020] As shown in Figures 1-3, the right side of the mechanism body 21 is equipped with a motor 31 via a pair of upper and lower mounting members 30. The motor 31 is, for example, a motor with a cycloidal reducer (registered trademark) and is variable speed controllable by a control device (not shown). The output shaft of the motor 31 (not shown, output shaft of the cycloidal reducer) has a drive pulley 33. A tensioned endless rubber belt 34 is stretched between the drive pulley 33 of the motor 31 and the driven pulley 26 of the shaft 23. Therefore, when the motor 31 is driven, the shaft 23 rotates around its axis.

[0021] As shown in Figures 1-3, the tip of the shaft 23 is equipped with a gas pipe 40 extending vertically. The gas pipe 40 has a hollow section 41 inside, through which an inert gas can pass. The base end (upper end) of the gas pipe 40 has a bracket 42. The bracket 42 of the gas pipe 40 and the bracket 27 of the shaft 23 are fastened together by four bolts 43. Because they are fastened together by four bolts 43 in this way, the gas pipe 40 and the shaft 23 can be firmly connected. Therefore, when the motor 31 is started, the gas pipe 40 rotates around the axis together with the shaft 23.

[0022] As shown in Figures 1-3, the tip (lower end) of the gas pipe 40 is a blowout hole 40a for blowing out inert gas, and a threaded portion 44 with a smaller diameter than the general part of the gas pipe 40 is formed thereon. The outer surface of the threaded portion 44 has a male thread 44a. The tip of the gas pipe 40 has an impeller 50 that is roughly disc-shaped (projecting radially) and extends in a direction perpendicular to the vertical direction. The impeller 50 has, for example, a diameter of about 300 mm and is integrally molded from silicon nitride or the like. As shown in Figures 5-7, the center of the impeller 50 has a blowout hole 53 through which the surface 51 and the bottom surface 52 penetrate. The blowout hole 53 is passable for inert gas.

[0023] As shown in Figures 6-7, the discharge hole 53 also serves as a threaded portion 54 that can be threaded with the threaded portion 44 of the gas pipe 40. Therefore, a female thread 54a is formed on the inner circumferential surface of the threaded portion 54. The bottom surface 52 of the impeller 50 is provided with elongated grooves 55 in the radial direction, extending from the edge of the discharge hole 53 to the outer circumferential edge of the impeller 50. As shown in Figure 5, 16 elongated grooves 55 are formed on the bottom surface 52 of the impeller 50 at equal intervals (in this example, at 22.5° intervals).

[0024] As shown in Figure 6, the recess depth of the long groove 55 is about half the thickness of the impeller 50. Therefore, the recess depth of the long groove 55 is sufficient. The outer circumferential surface 56 of the impeller 50 has short grooves 57 through which the surface 51 and bottom surface 52 penetrate. Sixteen short grooves 57 are formed on the outer circumferential surface 56 of the impeller 50 at equal intervals (22.5° intervals in this example) and in the center of adjacent long grooves 55. The threaded portion 44 of the gas pipe 40 and the threaded portion 54 of the impeller 50 are screwed together. This allows the impeller 50 to be easily attached to the end of the gas pipe 40.

[0025] As shown in Figures 1-4, the lower surface of each reinforcing frame 13a of the lower horizontal frame 13 has a hanging member 60 that extends downward. The hanging members 60 are paired front to back. A baffle plate 61, which extends in a planar direction consisting of the vertical and horizontal directions, is fastened between the paired hanging members 60 with two bolts 62. That is, the baffle plate 61 is suspended sandwiched between the paired hanging members 60. Because it is fastened with two bolts 62 in this way, the baffle plate 61 can be firmly fastened to the hanging members 60.

[0026] As shown in Figures 1-4, the aluminum alloy molten metal processing apparatus 1 includes a lance pipe 65. The lance pipe 65 has a double-walled structure with a small-diameter pipe 66 and a large-diameter pipe 67 through which the small-diameter pipe 66 is inserted. The small-diameter pipe 66 is, for example, made of 2 / 8 inch pipe material. The large-diameter pipe 67 is, for example, made of 6 / 8 inch pipe material. The tip (lower end) of the lance pipe 65 is covered by a lid member 68.

[0027] As shown in Figure 8, the lid member 68 is provided with a through-hole shaped outlet 68a in the area corresponding to the outlet 66b of the small-diameter pipe 66. Therefore, the first hollow section 66a, which is the inside of the small-diameter pipe 66, communicates with the outside through the outlets 66b and 68a. Similarly, the lid member 68 is provided with multiple fine gas holes 68b in the area corresponding to the outlet 67b of the large-diameter pipe 67. Therefore, the second hollow section 67a, which is between the small-diameter pipe 66 and the large-diameter pipe 67, communicates slightly with the outside through the outlets 67b and 68b.

[0028] As shown in Figures 1-3, the upper part of the lance pipe 65 is inserted into a through hole 15a formed in the mounting plate 15, and is attached to the mounting plate 15 by a mounting member 69 so as to maintain this inserted state. The length of the lance pipe 65 is set so that the discharge port 66b of the small-diameter pipe 66 at its tip is located above the impeller 50.

[0029] As shown in Figures 2 and 9, the lance pipe 65 is positioned so that even if a vortex S is generated in the molten metal 3 due to the rotation of the gas pipe 40 and impeller 50, this generated vortex S will be blocked by the baffle plate 61. As explained in Figure 9, the vortex S in the molten metal 3 is generated in a clockwise direction. Therefore, the lance pipe 65 is provided behind the left baffle plate 61. Of course, it is not limited to the rear of the left baffle plate 61; the lance pipe 65 may also be provided in front of the right baffle plate 61.

[0030] Furthermore, the area blocked by the baffle plate 61 is not limited to the location of the lance pipe 65 shown in Figure 9, but can be anywhere within area A. Area A is the area enclosed by 2T × W in a plan view of the processing unit 4, on the opposite side of the baffle plate 61 from the vortex S of the molten metal 3 (downstream of the vortex S), and adjacent to the hanging member 60. Here, T is the thickness of the baffle plate 61, and W is the width of the baffle plate 61.

[0031] Next, the flux feeder 70 will be described with reference to Figures 1 to 3. As shown in Figures 1 to 3, the flux feeder 70, like the frame body 10 described above, comprises a hollow frame body 71 having a roughly rectangular parallelepiped shape, a servo motor 72 assembled inside the frame body 71, and a screw conveyor 73 driven by the servo motor 72.

[0032] As shown in Figure 10, the screw conveyor 73 comprises a substantially cylindrical housing 74 and a round shaft 76 inside the housing 74, which has multiple helical blades 77 forming a screw on its outer surface. The helical blades 77 are, for example, multiple flat springs, and these multiple flat springs are joined to the outer surface of the shaft 76 at regular intervals by welding. This makes it easy to manufacture the shaft 76 with the helical blades 77. It also ensures the accuracy of the discharge (cutting) of the screw conveyor 73. Therefore, flux can be supplied evenly and stably. For example, when supplying flux, the supply amount does not change before, during, or after the supply. Thus, flux can be stably added to the molten metal from the lance pipe 65, which will be described later.

[0033] As shown in Figures 1-3, the output shaft of the servo motor 72 is connected to the shaft 76 via a reduction gear (not shown). The upper part of the housing 74 is equipped with a hopper 78 capable of storing flux. The discharge port 78a of the hopper 78 communicates with the inside of the housing 74. Therefore, when the servo motor 72 is driven, the shaft 76 rotates around its axis. Thus, the flux stored in the hopper 78 can be cut out and discharged from the discharge port 75 formed at the front of the housing 74.

[0034] As shown in Figures 1 and 2, the flux feeder 70 is equipped with a controller 79, which is electrically connected to the servo motor 72. Therefore, the controller 79 can adjust the rotational speed of the servo motor 72. Consequently, the amount of flux discharged from the screw conveyor 73 can be adjusted arbitrarily. In other words, since the amount of flux discharged per unit time can be adjusted arbitrarily, a predetermined amount of flux can be discharged stably.

[0035] As shown in Figures 1 and 2, the flux feeder 70 is mounted on the lower horizontal frame 13 of the frame body 10. In other words, the flux feeder 70 is housed inside the frame body 10. Therefore, there is no risk of the flux feeder 70 protruding from the outer shape of the frame body 10. Thus, the processing unit 4 can be made into a compact structure. Of course, the flux feeder 70 could also be mounted on the upper horizontal frame 12 of the frame body 10. In that case, a large-capacity hopper 78 can be applied.

[0036] Next, the piping system of the processing unit 4 will be described with reference to Figure 10. As shown in Figure 10, a gas cylinder 80 is provided near the processing unit 4. The gas cylinder 80 is filled with an inert gas (argon gas, nitrogen gas, etc.). The gas cylinder 80 is equipped with a valve (not shown). When the valve is opened (the gas cylinder 80 is opened), the inert gas filled in the gas cylinder 80 is discharged. The main pipe 81 is connected to the gas cylinder 80. At its end, the main pipe 81 branches into three systems (first pipe 82, second pipe 83, and third pipe 84).

[0037] As shown in Figure 10, the first piping 82 includes a valve 82a that can adjust the internal pressure and a flow meter 82b that can detect the internal flow rate. The valve 82a is operable by an operator. The flow meter 82b is visible to an operator. The first piping 82 is connected to the base end (upper end) of the shaft 23. Therefore, inert gas can be blown out from the outlet hole 53 of the impeller 50 via the gas pipe 40 fastened to the shaft 23.

[0038] As shown in Figure 10, the second pipe 83 also includes a valve 83a that can adjust the internal pressure and a flow meter 83b that can detect the internal flow rate. The valve 83a is operable by the operator. The flow meter 83b is visible to the operator. The second pipe 83 is connected to the second hollow section 67a at the base end (upper end) of the lance pipe 65. Therefore, inert gas can be blown out from the gas hole 68b of the cap member 68 at the tip of the lance pipe 65.

[0039] As shown in Figure 10, the third piping 84 comprises a third piping 84 (upstream) and a third piping 84 (downstream). The third piping 84 (upstream) also includes a valve 84a capable of adjusting the internal pressure and a flow meter 84b capable of detecting the internal flow rate. The valve 84a is operable by the operator. The flow meter 84b is visible to the operator. The third piping 84 (upstream) is connected to the tip of the housing 74 of the flux feeder 70. The third piping 84 (downstream) is connected from the outlet 75 of the housing 74 to the first hollow section 66a at the base end (upper end) of the lance pipe 65. Therefore, flux and inert gas can be blown out from the outlet 68a of the lid member 68 at the tip of the lance pipe 65.

[0040] Next, the operation of the aluminum alloy molten metal processing apparatus 1 will be explained. First, the molten metal 3, melted by the melting furnace, is poured into the processing tank 2. Next, the servo motor 72 is driven to discharge the flux from the discharge port 75 of the housing 74 of the screw conveyor 73 of the flux feeder 70. The amount of flux discharged is determined, for example, so that the flux concentration is 0.2% by weight relative to the molten metal 3. For example, 2 kg of flux is added to 1000 kg of molten metal 3.

[0041] Next, the valve (not shown) of gas cylinder 80 is opened. Then, the valves 82a to 84a of the first pipe 82 to the third pipe 84 are opened. At that time, the pressure inside the first pipe 82 to the third pipe 84 is adjusted so that the flow rate readings on the flow meters 82b to 84b of the first pipe 82, second pipe 83, and third pipe 84 are, for example, in a ratio of 1:1:2. In other words, the opening degree of each valve 82a to 84a is adjusted.

[0042] For example, if the flow rate of inert gas discharged from gas cylinder 80 is 0.4 m³, the opening of valves 82a to 84a is adjusted so that the flow rates inside the first pipe 82, second pipe 83, and third pipe 84 are 0.1 m³, 0.1 m³, and 0.2 m³, respectively. As a result, as shown in Figure 10, the inert gas flows from gas cylinder 80 to the main pipe 81, first pipe 82, hollow section 24 of shaft 23, hollow section 41 of gas pipe 40, and the outlet hole 53 of impeller 50 in that order. The inert gas is then discharged from the outlet hole 53 of impeller 50. In other words, the inert gas is blown into the molten metal 3.

[0043] Simultaneously, as shown in Figures 8 and 10, the inert gas flows from the gas cylinder 80 through the main pipe 81, the second pipe 83, the second hollow section 67a of the lance pipe 65, and the gas hole 68b of the lid member 68. The inert gas is then discharged from the gas hole 68b of the lid member 68. In other words, the inert gas is blown into the molten metal 3.

[0044] Simultaneously, as shown in Figures 8 and 10, the inert gas flows from the gas cylinder 80 to the main pipe 81, the third pipe 84 (upstream side), the tip of the housing 74, the third pipe 84 (downstream side), the first hollow section 66a of the lance pipe 65, and the outlet 68a of the lid member 68. The inert gas is then discharged from the outlet 68a of the lid member 68.

[0045] As previously explained, flux is discharged from the outlet 75 of the housing 74 of the flux feeder 70. Therefore, flux flows along with the inert gas to the third pipe 84 (downstream side), the first hollow section 66a of the lance pipe 65, and the outlet 68a of the lid member 68. In other words, the inert gas is blown into the molten metal 3 and the flux is added stably at the same time.

[0046] When flux is stably added to the molten metal 3, the added flux reacts with oxides in the molten metal 3 as it floats to the surface. As a result, oxides are separated from the molten metal 3 and float to the surface of the molten metal 3. Therefore, the floating oxides can be recovered. In other words, oxides in the molten metal 3 can be removed.

[0047] Furthermore, since the lance pipe 65 has a double structure, the periphery of the first hollow section 66a through which the flux flows is covered by the second hollow section 67a through which only inert gas flows. Therefore, the inert gas flowing through the second hollow section 67a shields the heat transferred from the molten metal 3 to the flux. Next, once the addition of a predetermined amount of flux is complete, the motor 31 is driven to rotate the impeller 50 together with the gas pipe 40.

[0048] Furthermore, even when the gas pipe 40 and impeller 50 rotate, the baffle plate 61 prevents the formation of vortices S around the axis of the gas pipe 40 within the molten metal 3. Therefore, there is no risk of the oxide film formed on the surface of the molten metal 3 cracking around the gas pipe 40, and thus there is no risk of new oxides being formed on the surface of the molten metal 3. As a result, there is no risk of new oxides being formed within the molten metal 3. In addition, the rotation of the gas pipe 40 and impeller 50 agitates the molten metal 3. Therefore, the added flux spreads throughout the molten metal 3. Consequently, the flux reacts completely with the oxides in the molten metal 3, and any loss of oxides within the molten metal 3 can be suppressed.

[0049] Furthermore, even if a vortex S is generated around the axis of the gas pipe 40 in the molten metal 3 due to the rotation of the gas pipe 40 and the impeller 50, the lance pipe 65 is positioned so that the vortex S in the molten metal 3 generated by these rotations is blocked by the baffle plate 61 (see Figures 2 and 9). Therefore, even if a vortex S is generated in this way, the baffle plate 61 blocks it so that there is no risk of the generated vortex S directly hitting the lance pipe 65.

[0050] Furthermore, because the impeller 50 has a large diameter (for example, about 300 mm), the inert gas blown into the molten metal 3 can be spread throughout the molten metal 3 even at a low rotation speed of the gas pipe 40 (even if the rotation speed of the gas pipe 40 is reduced). Also, because the rotation speed of the gas pipe 40 is low, there is no risk of the oxide film formed on the surface of the molten metal 3 cracking. Therefore, there is no risk of a new oxide film forming from the surface where the oxide film has cracked. In addition, because the rotation speed of the gas pipe 40 is low, the rotation speeds of the shaft 23 and the impeller 50 are also low. Consequently, the frictional effect on the molten metal 3 is also reduced, and wear on these shafts, gas pipes 40, impeller 50 and baffle plates 61 can be suppressed.

[0051] Furthermore, hydrogen in the molten metal 3 dissolves into bubbles generated by the inert gas blown into the molten metal 3. As a result, the bubbles containing dissolved hydrogen float to the surface of the molten metal 3. Consequently, the hydrogen dissolved in the molten metal 3 is released into the atmosphere from the floating bubbles. In other words, hydrogen in the molten metal 3 can be removed (degassed). Since oxides and hydrogen in the molten metal 3 can be removed in this way, the quality of the castings cast from the molten metal 3 can be improved.

[0052] Furthermore, the bubbles generated by the inert gas blown into the molten metal 3 become finer bubbles due to the rotation of the gas pipe 40. As a result, the number of bubbles in the molten metal 3 increases, and the total surface area of ​​the bubbles in the molten metal 3 also increases. Consequently, more hydrogen can be dissolved into the bubbles in the molten metal 3.

[0053] Furthermore, the bubbles generated by the inert gas discharged from the outlet 68a of the lid member 68 flow radially along the impeller 50 due to the centrifugal force generated by the rotation of the impeller 50. At this time, bubbles that enter the long grooves 55 of the impeller 50 come into contact with (are cut by) the long grooves 55, becoming finer bubbles. As a result, the total surface area of ​​the bubbles in the molten metal 3 increases as described above. Consequently, more hydrogen in the molten metal 3 can be dissolved into the bubbles.

[0054] Furthermore, the bubbles, which become finer upon contact with the long groove 55, then enter the short groove 57 of the impeller 50. As a result, the fine bubbles that enter the short groove 57 are moved radially outward (blasted) by the centrifugal force of the impeller 50. Therefore, the bubbles generated by the inert gas can be spread more widely within the molten metal 3. Consequently, hydrogen can be removed from the molten metal 3 over a wide area.

[0055] The aluminum alloy molten metal processing apparatus 1 according to this embodiment is configured as described above. According to this configuration, the aluminum alloy molten metal processing apparatus 1 includes a flux feeder 70 that supplies flux by the rotation of a spiral blade 77. Furthermore, the aluminum alloy molten metal processing apparatus 1 includes a gas pipe 40 having a blowout hole 40a at its end for blowing out inert gas, an impeller 50 that protrudes radially from near the end of the gas pipe 40 and rotates together with the gas pipe 40, and a baffle plate 61 adjacent to the impeller 50. The lance pipe 65 has an outlet 66b for discharging the flux supplied from the flux feeder 70.

[0056] Therefore, even when the gas pipe 40 rotates together with the impeller 50, the baffle plate 61 prevents the formation of vortices S around the axis of the gas pipe 40 in the molten metal 3. Consequently, there is no risk of the oxide film formed on the surface of the molten metal 3 cracking around the gas pipe 40, and therefore there is no risk of new oxides being formed on the surface of the molten metal 3. As a result, there is no risk of new oxides being formed in the molten metal 3. In addition, since flux is supplied by the rotation of the spiral blades 77, the flux supply is stable. Therefore, for example, when flux is fed from the hopper 78 into the housing 74, there is no risk of the flux clogging at the bottom of the hopper 78, or of a large amount of flux being fed from the hopper 78 into the housing 74 and the pressurized flux clogging the inside of the lance pipe. Consequently, flux can be added to the molten metal 3 stably. As a result, oxides in the molten metal 3 can be removed. Furthermore, since the inert gas blown out from the outlet 40a of the gas pipe 40 is stirred into the molten metal 3 by the impeller 50, hydrogen can be removed from the molten metal 3.

[0057] Furthermore, with this configuration, the lance pipe 65 is positioned where the vortices S of the molten metal 3 generated by the rotation of the impeller 50 are blocked by the baffle plate 61. Therefore, even if vortices S are generated in the molten metal 3 by the rotation of the impeller 50, these vortices S are blocked by the baffle plate 61. Consequently, there is no risk of these vortices S directly hitting the lance pipe 65. Thus, deformation of the lance pipe 65 can be suppressed.

[0058] Furthermore, with this configuration, the aluminum alloy molten metal processing apparatus 1 has a frame body 10 that rotatably holds the gas pipe 40. The frame body 10 has a motor 31 that rotates the gas pipe 40 around its axis. The baffle plate 61 and the lance pipe 65 are held by the frame body 10. Therefore, there is no risk of displacement of the baffle plate 61 due to vortices S of the molten metal 3 generated by the rotation of the impeller 50. The same applies to the lance pipe 65. Thus, the position of the lance pipe 65 relative to the baffle plate 61 can be maintained in an appropriate state.

[0059] Furthermore, with this configuration, the outlet 66b of the lance pipe 65 is located above the impeller 50. Therefore, the impeller 50 agitates the molten metal 3 below the blown-out (added) flux. Thus, the flux can be agitated efficiently.

[0060] Furthermore, in this configuration, the lance pipe 65 has a small-diameter pipe 66 and a large-diameter pipe 67 through which the small-diameter pipe 66 is inserted. Flux is flowed through the small-diameter pipe 66, and an inert gas is flowed between the small-diameter pipe 66 and the large-diameter pipe 67, and the flux and inert gas are discharged from the outlets 66b and 67b. As a result, the inert gas flowing between the small-diameter pipe 66 and the large-diameter pipe 67 shields the heat transferred from the molten metal 3 to the flux. Therefore, the risk of the flux melting inside the lance pipe 65 due to the heat transferred from the molten metal 3 can be suppressed. Thus, the clogging of the flux inside the lance pipe 65 can be suppressed.

[0061] Although embodiments have been described with reference to the above structure, it will be apparent to those skilled in the art that many substitutions, improvements, and modifications are possible without departing from the purpose of the present invention. Therefore, embodiments may include all substitutions, improvements, and modifications that do not depart from the spirit and purpose of the appended claims. For example, embodiments are not limited to a particular structure and can be modified as follows. In addition, each numerical value disclosed in the embodiments can be changed as appropriate.

[0062] In this embodiment, an example was described in which 16 long grooves 55 are formed at equal intervals (in this example, at 22.5° intervals) on the bottom surface 52 of the impeller 50. Alternatively, 8 or 12 long grooves 55 may be formed at equal intervals on the bottom surface 52 of the impeller 50. The same applies to the short grooves 57.

[0063] In this embodiment, the lance pipe 65 was described as having a double structure with a small-diameter pipe 66 and a large-diameter pipe 67 through which the small-diameter pipe 66 is inserted. Alternatively, the lance pipe 65 may have a triple structure with a medium-diameter pipe 64 between the small-diameter pipe 66 and the large-diameter pipe 67 (see Figure 11). In that case, an air layer or refractory material is inserted into the third hollow section 64a between the medium-diameter pipe 64 and the small-diameter pipe 66, and an inert gas is flowed through the second hollow section 67a between the medium-diameter pipe 64 and the large-diameter pipe 67.

[0064] In this triple-layer structure, the heat transferred from the molten metal 3 to the flux is shielded by the inert gas flowing through the second hollow section 67a and the air layer or refractory material in the third hollow section 64a. Therefore, the risk of the flux melting inside the lance pipe 65 due to the heat from the molten metal 3 is further suppressed. Consequently, the clogging of the flux inside the lance pipe 65 can be further suppressed.

[0065] In this triple-walled structure, the small-diameter pipe 66 is, for example, a 1 / 8 inch pipe, the medium-diameter pipe 64 is, for example, a 3 / 8 inch pipe, and the large-diameter pipe 67 is, for example, a 6 / 8 inch pipe. Alternatively, the small-diameter pipe 66 could be, for example, a 2 / 8 inch pipe, the medium-diameter pipe 64 could be, for example, a 5 / 8 inch pipe, and the large-diameter pipe 67 could be, for example, a 1-inch pipe.

[0066] Furthermore, as mentioned above, the Lance Pipe 65 is not limited to a double or triple structure; it can have any number of layers as long as it has multiple layers. For example, the Lance Pipe 65 can have a quadruple structure. In that case, as with the triple structure, an additional layer containing air or refractory material will be added. Of course, instead of an air layer or a layer containing refractory material, an additional layer through which an inert gas flows may be added. In other words, any layer that provides insulation is acceptable.

[0067] Furthermore, in this embodiment, silicon nitride was used as an example of the material forming the impeller 50. However, it is not limited to this. The material forming the impeller 50 may also be graphite.

[0068] Furthermore, in the embodiment, an example was described in which the pressure inside the first pipe 82 to the third pipe 84 is adjusted so that the flow rate readings of the flow meters 82b to 84b in the first pipe 82, the second pipe 83, and the third pipe 84 are, for example, in a ratio of 1:1:2, i.e., the opening degree of each valve 82a to 84a is adjusted. However, the method is not limited to this, and the pressure inside the first pipe 82 to the third pipe 84 is adjusted so that the flow rate readings of the flow meters 82b to 84b are in a ratio of 2:1:4, i.e., the opening degree of each valve 82a to 84a is adjusted. In that case, for example, if the flow rate of the inert gas discharged from the gas cylinder 80 is 3.5 m³, the opening degrees of each valve 82a to 84a are adjusted so that the flow rates inside the first pipe 82, the second pipe 83, and the third pipe 84 are 1 m³, 0.5 m³, and 2 m³, respectively. Various ratios for these flow rate readings can be considered and determined as appropriate. [Explanation of symbols]

[0069] 1. Aluminum alloy molten metal treatment device 64 Medium diameter pipe 65 Lance Pipe 66 Small diameter pipes 66b Outlet 67 Large diameter pipes

Claims

1. Aluminum alloy molten metal treatment apparatus, A processing tank where molten metal is stored, A processing unit is provided, The aforementioned processing unit is A lance pipe having an outlet for discharging flux into the molten metal, An impeller that rotates to stir the molten metal and generate a vortex in the molten metal, It has a baffle plate that faces the vortex flow, The lance pipe has a small diameter pipe and a large diameter pipe through which the small diameter pipe is inserted. The flux is flowed through the small-diameter pipe, an inert gas is flowed between the small-diameter pipe and the large-diameter pipe, and the flux and the inert gas are discharged from the outlet. The baffle plate is suspended from the processing unit via a hanging member, An aluminum alloy molten metal processing apparatus in which the lance pipe is positioned downstream of the vortex on at least one of the baffle plates, the lance pipe in the molten metal is hidden by the at least one baffle plate when viewed from upstream of the vortex on the at least one baffle plate, and the outlet of the lance pipe is located above the lower end of the at least one baffle plate.

2. The aluminum alloy molten metal processing apparatus according to claim 1, The lance pipe has a medium-diameter pipe between the small-diameter pipe and the large-diameter pipe, An air layer or refractory material is inserted between the medium-diameter pipe and the small-diameter pipe. An aluminum alloy molten metal processing apparatus in which the inert gas is flowed between the medium-diameter pipe and the large-diameter pipe.

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