Aluminum alloy molten metal treatment equipment

Abstract

To provide a molten aluminum alloy processing device which can remove oxides in a molten metal without generating new oxides in the molten metal while removing hydrogen in the molten metal.SOLUTION: A molten aluminum alloy processing device 1 includes a flux feeder 70 which supplies a flux by rotation of a screw. Further, the molten aluminum alloy processing device 1 includes: a gas pipe 40 including, at an end, a blowout hole 40a for blowing out an inactive gas; an impeller 50 which protrudes from a position near the end of the gas pipe 40 in a radial direction and rotates with the gas pipe 40; and a baffle plate 61 located adjacent to the impeller 50. The lance pipe 65 has a discharge port 66b for discharging the fluid supplied from the flux feeder 70.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, when casting an aluminum alloy, various treatments are performed on molten aluminum alloy (hereinafter referred to as "molten metal"). Patent Document 1 listed below discloses a molten metal treatment device that adds flux to the molten metal and injects a non-oxidizing gas (e.g., argon gas or nitrogen gas) into the molten metal. When flux is added to the molten metal, the added flux reacts with oxides in the molten metal as it floats in the molten metal. This separates the oxides from the molten metal, and the separated oxides float to the surface of the molten metal. Therefore, the floated oxides can be recovered. In other words, the oxides in the molten metal can be removed. Patent Document 2 listed below also discloses a method of adding flux to an impurity removal device. In this addition method, a lance pipe is inserted into the molten metal, and flux is added to the molten metal together with an inert gas from the tip of the inserted lance pipe.

[0003] On the other hand, when non-oxidizing gas is blown into molten metal, the hydrogen in the molten metal dissolves in the bubbles generated by the blown non-oxidizing gas. Then, the bubbles with dissolved hydrogen rise to the surface of the molten metal. Therefore, the hydrogen dissolved in the molten metal is released into the atmosphere from the rising bubbles. In other words, the hydrogen in the molten metal can be removed (degassed). In this way, the removal of oxides and hydrogen from the molten metal can improve the quality of the castings made from the molten metal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-143483 [Patent Document 2] Japanese Patent Application Publication No. 6-91350 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 includes an agitator (impeller) for stirring the flux added to the molten metal and the non-oxidizing gas injected into the molten metal within the molten metal. Therefore, the rotation of the shaft to operate the agitator could create a vortex around the shaft axis within the molten metal. Therefore, the oxide film formed on the surface of the molten metal could crack around the shaft, and the molten metal surface at the cracked area could be exposed to the air and oxidized, generating new oxides. As a result, new oxides could be generated within the molten metal. Furthermore, the technology of Patent Document 2 uses a hose to pump the flux and inert gas from a hopper into a tank. This can lead to problems such as clogging the bottom of the hopper when the flux is poured into the tank, or clogging the lance pipe when a large amount of flux is poured into the tank from the hopper. Therefore, there is a risk that the flux cannot be added stably to the molten metal. As a result, there is a risk that the oxides in the molten metal cannot be removed. Furthermore, among aluminum alloy molten metal treatment devices, there are those with baffle plates, those without baffle plates, those with unique impeller shapes, those in which the impeller shaft periodically rotates forward and backward, and those in which the shaft periodically rises and falls. All of these devices generate new oxides in the molten metal, resulting in degassing. Furthermore, if the impeller shape and the inert gas discharge rate are not optimized, there is a risk of oxides increasing in the molten metal. Therefore, there has been a demand for an aluminum alloy molten metal treatment device that can remove oxides from the molten metal while removing hydrogen from the molten metal without generating new oxides in the molten metal. [Means for solving the problem]

[0006] In one aspect of the present disclosure, the aluminum alloy molten metal treatment apparatus includes a flux feeder that supplies flux by rotating a screw. The aluminum alloy molten metal treatment apparatus further includes a gas pipe having an outlet port at an end for blowing out an inert gas, an impeller that protrudes radially from near the end of the gas pipe and rotates together with the gas pipe, and a baffle plate adjacent to the impeller. The lance pipe has an outlet for discharging the flux supplied from the flux feeder.

[0007] Therefore, even when the gas pipe rotates together with the impeller, the baffle plate prevents vortices from forming around the axis of the gas pipe within the molten metal. Therefore, the oxide film formed on the surface of the molten metal is not likely to crack around the gas pipe, and new oxides are not likely to form on the surface of the molten metal. As a result, there is no risk of new oxides forming within the molten metal. Furthermore, since the flux is supplied by the rotation of the screw, the supply of flux is stable. Therefore, for example, there is no risk of the flux clogging the bottom of the hopper when flux is poured into the tank from the hopper, or of the pressure-fed flux clogging the inside of the lance pipe when a large amount of flux is poured from the hopper into the tank. Therefore, flux can be stably added to the molten metal. As a result, oxides within the molten metal can be removed. Furthermore, the inert gas blown from the gas pipe outlet is stirred into the molten metal by the impeller, thereby removing hydrogen from the molten metal.

[0008] In another feature of the present disclosure, the lance pipe is positioned where a vortex of the molten metal generated by the rotation of the impeller is interrupted by a baffle plate.

[0009] Therefore, even if a vortex occurs in the molten metal due to the rotation of the impeller, the vortex is blocked by the baffle plate, so there is no risk of the vortex directly hitting the lance pipe, and deformation of the lance pipe can be suppressed.

[0010] Another feature of the present disclosure is that the apparatus includes a base that rotatably holds the gas pipe. The base includes a motor that is mounted to the base and rotates the gas pipe about its axis. The baffle plate and lance pipe are held by the base. Therefore, there is no risk of the baffle plate being displaced by a vortex of molten metal caused by the rotation of the impeller. The same applies to the lance pipe. Therefore, the position of the lance pipe relative to the baffle plate can be maintained in an appropriate state.

[0011] In another feature of the present disclosure, the outlet of the lance pipe is located above the impeller, so that the impeller stirs the molten metal below the injected (added) flux, thereby enabling efficient stirring of the flux.

[0012] In another feature of the present disclosure, the lance pipe includes a small diameter pipe and a large diameter pipe through which the small diameter pipe is inserted. Flux flows through the small diameter pipe, an inert gas flows between the small diameter pipe and the large diameter pipe, and the flux and the inert gas are discharged from an outlet. Therefore, 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. This reduces the risk of the flux melting inside the lance pipe due to the heat transferred from the molten metal. Therefore, clogging of the lance pipe with flux can be reduced. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a front view of an aluminum alloy molten metal treatment apparatus according to an embodiment. FIG. [Figure 2] FIG. 2 is a plan view of the aluminum alloy molten metal treatment apparatus of FIG. 1. [Figure 3] FIG. 2 is a left side view of the aluminum alloy molten metal treatment apparatus of FIG. 1. [Figure 4] FIG. 2 is a bottom view of the aluminum alloy molten metal treatment apparatus of FIG. 1. [Figure 5] FIG. 2 is a bottom view of the impeller of FIG. 1. [Figure 6] 6 is a cross-sectional view of the impeller of FIG. 5 taken along line VI-VI. [Figure 7]FIG. 7 is a cross-sectional view of the impeller of FIG. 5 taken along line VII-VII. [Figure 8] FIG. 2 is a longitudinal sectional view of the tip of the lance pipe of FIG. 1. [Figure 9] FIG. 2 is an enlarged view illustrating the arrangement of the lance pipes in FIG. 1. [Figure 10] FIG. 2 is a piping diagram of the aluminum alloy molten metal treatment apparatus of FIG. 1. [Figure 11] 9 is a modified example of the lance pipe of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0014] One embodiment will be described with reference to Figures 1 to 10. As shown in Figure 1, an aluminum alloy molten metal treatment apparatus 1 includes a treatment tank 2 and a treatment unit 4. The treatment tank 2 and the treatment unit 4 will be described separately below. In the following description, up and down, front and back, and left and right indicate the directions indicated in each figure.

[0015] As shown in Figures 1 to 4, the treatment tank 2 is, for example, a circular tank with a bottom and an inner diameter of about 600 mm, and is installed adjacent to a melting furnace (not shown). Molten aluminum (hereinafter simply referred to as "molten metal 3") made of an aluminum alloy melted by the melting furnace is poured into the treatment tank 2 and stored therein. The treatment unit 4 includes a frame body 10, a gas supply rotation mechanism 20, and a flux feeder 70. The frame body 10, the gas supply rotation mechanism 20, and the flux feeder 70 will be described individually below.

[0016] First, the frame body 10 will be described with reference to Figures 1 to 4. As shown in Figures 1 to 4, the frame body 10 includes four vertical frames 11, a rectangular upper horizontal frame 12, and a rectangular lower horizontal frame 13 that faces the upper horizontal frame 12 from above and below. The upper horizontal frame 12 and the lower horizontal frame 13 are set so that their lengths in the left-right direction are longer than their lengths in the front-to-rear direction.

[0017] 1 to 4, the upper surfaces of the four vertical frames 11 are connected to the lower surface of the four corners of the upper horizontal frame 12. Similarly, the lower surfaces of the four vertical frames 11 are connected to the upper surface of the four corners of the lower horizontal frame 13. By being connected in this manner, the frame body 10 is hollow and has an outer shape that is approximately rectangular parallelepiped.

[0018] As shown in Figures 1 to 4, handles 14 are attached to the front and rear opposing portions of the upper horizontal frame 12. The handles 14 are attached so that they protrude away from each other. The handles 14 are generally U-shaped so that they can be easily grasped by an operator (not shown). By grasping the handles 14, the operator can easily carry the processing unit 4.

[0019] As shown in Figures 1 to 4, mounting plates 15 that bridge the front and rear opposing portions of the upper horizontal frame 12 are attached to the upper surfaces of the portions 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 the front and rear opposing portions of the upper horizontal frame 12 are connected to the portions. The reinforcing frames 12a can suppress distortion that occurs in the upper horizontal frame 12.

[0020] 1 to 4, hooks 17 are attached to both the front and rear edges of the mounting plate 15. The hooks 17 pass through the mounting plate 15 and are supported by the upper horizontal frame 12. Therefore, by hooking the hook portion (not shown) of a sling wire connected to a crane or the like onto the hooks 17, the processing unit 4 can be easily raised and lowered by the crane or the like.

[0021] 1 to 4, the lower horizontal frame 13 has four leg members 18 extending downward to a position where the processing unit 4 can be placed on the upper edge of the processing tank 2. The four leg members 18 are support members that support the processing unit 4 itself, and therefore have sufficient strength to withstand the weight of the processing unit 4.

[0022] As shown in Figures 1 to 4, reinforcing frames 13a are connected to opposing front and rear portions of the lower horizontal frame 13, bridging the two. Two reinforcing frames 13a are provided, one on the left and one on the right. These two reinforcing frames 13a can suppress distortion occurring in the lower horizontal frame 13. The frame body 10 corresponds to the base described in the claims.

[0023] Next, the gas supply rotation mechanism 20 will be described with reference to Figures 1 to 3. As shown in Figures 1 to 3, the gas supply rotation mechanism 20 is a supply source for blowing an inert gas (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 rotation mechanism 20 has a mechanism main 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 lower horizontal frame 13 facing each other at the front and rear so as to bridge the opposing front and rear portions of the lower horizontal frame 13.

[0024] As shown in Figures 1 to 3, the mechanism body 21 includes a shaft 23 extending in the vertical direction. The shaft 23 has a hollow portion 24 that is hollow inside. The hollow portion 24 is passable with an inert gas. The shaft 23 is supported by bearings 25 provided at the top and bottom of the mechanism body 21 so as to be rotatable around an axis whose axial direction is the vertical direction relative to the mechanism body 21. The base end (upper end) of the shaft 23 includes a driven pulley 26 that rotates together with the shaft 23. The tip end (lower end) of the shaft 23 includes a bracket 27.

[0025] As shown in FIGS. 1 to 3, the right side of the mechanism body 21 is provided with a motor 31 via a pair of upper and lower mounting members 30. The motor 31 is, for example, a motor with a cyclo reducer (registered trademark), and its speed can be varied using a control device (not shown). The output shaft of the motor 31 (the output shaft of the cyclo reducer, not shown) has a driving pulley 33. An endless rubber belt 34 is tensioned and stretched between the driving 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 about its axis.

[0026] As shown in FIGS. 1 to 3, the tip of the shaft 23 is provided with a gas pipe 40 extending in the vertical direction. The gas pipe 40 has a hollow portion 41 that is hollow inside. The hollow portion 41 is capable of passing an inert gas. 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 via four bolts 43. Fastened together via the four bolts 43 in this manner, the gas pipe 40 and the shaft 23 can be firmly fastened together. Therefore, when the motor 31 starts, the gas pipe 40 rotates around its axis together with the shaft 23.

[0027] As shown in FIGS. 1 to 3, the tip (lower end) of the gas pipe 40 is an outlet 40a for blowing out the inert gas, and is formed with a threaded portion 44 having a smaller diameter than the general portion of the gas pipe 40. The outer peripheral surface of the threaded portion 44 is formed with a male thread 44a. The tip of the gas pipe 40 is provided with an impeller 50 having a generally disk-like shape (a shape protruding in the radial direction) extending in a direction perpendicular to the up-down direction. The impeller 50 has a diameter of, for example, about 300 mm and is integrally molded from silicon nitride or the like. As shown in FIGS. 5 to 7, the center of the impeller 50 is provided with an outlet 53 penetrating from a surface 51 to a bottom 52. The outlet 53 is capable of passing the inert gas.

[0028] 6 and 7, the blowout holes 53 also serve as threaded portions 54 that can be threadedly engaged with the threaded portions 44 of the gas pipe 40. Therefore, a female thread 54a is formed on the inner peripheral surface of the threaded portion 54. The bottom surface 52 of the impeller 50 is provided with long grooves 55 extending radially from the edge of the blowout holes 53 to the outer peripheral edge of the impeller 50. As shown in FIG. 5, 16 long grooves 55 are formed on the bottom surface 52 of the impeller 50 at equal intervals (in this example, intervals of 22.5°).

[0029] As shown in FIG. 6, the recess depth of the long grooves 55 is approximately half the thickness of the impeller 50. Therefore, the recess depth of the long grooves 55 is sufficient. The outer peripheral surface 56 of the impeller 50 has short grooves 57 that penetrate from the top surface 51 to the bottom surface 52. Sixteen short grooves 57 are formed on the outer peripheral surface 56 of the impeller 50 at equal intervals (in this example, at intervals of 22.5°) and in the centers of adjacent long grooves 55. The threaded portion 44 of the gas pipe 40 is threadedly engaged with the threaded portion 54 of the impeller 50. This allows the impeller 50 to be easily attached to the tip of the gas pipe 40.

[0030] As shown in FIGS. 1 to 4, the lower surface of each reinforcing frame 13a of lower horizontal frame 13 has a downwardly extending hanging member 60. Hanging members 60 are paired in the front and rear. A baffle plate 61 extending in a planar direction consisting of the up-down and left-right directions is fastened between the paired hanging members 60 with two bolts 62. In other words, baffle plate 61 is suspended in a sandwiched state between the paired hanging members 60 in the front and rear. Fastened in this manner with two bolts 62, baffle plate 61 can be firmly fastened to hanging member 60.

[0031] As shown in Figures 1 to 4, the aluminum alloy molten metal treatment apparatus 1 includes a lance pipe 65. The lance pipe 65 has a double structure including 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, a 2-minute pipe material. The large diameter pipe 67 is, for example, a 6-minute pipe material. The tip (lower end) of the lance pipe 65 is covered by a lid member 68.

[0032] 8, the cover member 68 has a through-hole-shaped outlet 68a at a position corresponding to the outlet 66b of the small diameter pipe 66. Therefore, the first hollow portion 66a, which is the interior of the small diameter pipe 66, communicates with the outside via the outlet 66b and the outlet 68a. Similarly, the cover member 68 has a plurality of minute gas holes 68b at a position corresponding to the outlet 67b of the large diameter pipe 67. Therefore, the second hollow portion 67a, which is between the small diameter pipe 66 and the large diameter pipe 67, communicates slightly with the outside via the outlet 67b and the gas holes 68b.

[0033] 1 to 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 the tip is positioned above the impeller 50.

[0034] 2 and 9, the lance pipe 65 is provided in a position where, even if a vortex S is generated in the molten metal 3 due to the rotation of the gas pipe 40 and the impeller 50, the generated vortex S is blocked by the baffle plate 61. As explained with reference to FIG. 9, the vortex S of 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, the lance pipe 65 is not limited to being provided behind the left baffle plate 61, and it may also be provided in front of the right baffle plate 61.

[0035] 9, the area blocked by the baffle plate 61 may be any area within area A. In a plan view of the processing unit 4, area A is on the opposite side of the baffle plate 61 from the vortex S of the molten metal 3 (downstream side of the vortex S), and is a range surrounded by 2T×W 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.

[0036] 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 includes a hollow frame body 71 having a substantially rectangular parallelepiped outer shape, a servo motor 72 assembled inside the frame body 71, and a screw conveyor 73 driven by the servo motor 72, similar to the frame body 10 described above.

[0037] As shown in FIG. 10, the screw conveyor 73 includes a generally cylindrical housing 74 and a round shaft 76 with a plurality of spiral blades 77 on the outer periphery of the housing 74. The spiral blades 77 are, for example, a plurality of flat springs, which are welded to the outer periphery of the shaft 76 at regular intervals. This simplifies the manufacture of the shaft 76 with the spiral blades 77. It also ensures accurate discharge (extraction) of the screw conveyor 73. This allows for a stable and uniform supply of flux. For example, the supply amount of flux does not change before, during, or after the supply. This allows for stable addition of flux to the molten metal from the lance pipe 65, which will be described later.

[0038] As shown in FIGS. 1 to 3, the output shaft of the servo motor 72 is connected to a shaft 76 via a reducer (not shown). The upper part of the housing 74 is provided with a hopper 78 capable of storing flux. A 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 about its axis. Therefore, the flux stored in the hopper 78 can be cut out and discharged from a discharge port 75 formed at the tip of the housing 74.

[0039] 1 and 2, the flux feeder 70 includes a controller 79, which is electrically connected to the servo motor 72. Therefore, the rotation speed of the servo motor 72 can be adjusted by the controller 79. Therefore, 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 stably discharged.

[0040] As shown in FIGS. 1 and 2, the flux feeder 70 is placed on the lower horizontal frame 13 of the frame body 10. That is, the flux feeder 70 is stored inside the frame body 10. Therefore, there is no risk that the flux feeder 70 protrudes from the outer shape of the frame body 10. This allows the processing unit 4 to have a compact structure. Of course, the flux feeder 70 may also be placed on the upper horizontal frame 12 of the frame body 10. In that case, a large-capacity hopper 78 can be applied.

[0041] Next, the piping system of the processing unit 4 will be described with reference to FIG. 10. As shown in FIG. 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 provided with a valve (not shown). When the valve is opened (when the gas cylinder 80 is unplugged), the inert gas filled in the gas cylinder 80 is discharged. A main pipe 81 is connected to the gas cylinder 80. The main pipe 81 branches into three systems (a first pipe 82, a second pipe 83, and a third pipe 84) at its tip.

[0042] 10, the first pipe 82 is equipped with a valve 82a capable of adjusting the internal pressure and a flow meter 82b capable of detecting the internal flow rate. The valve 82a can be operated by an operator. The flow meter 82b can be visually observed by an operator. The first pipe 82 is connected to the base end (upper end) of the shaft 23. Therefore, the inert gas can be blown out from the blowing holes 53 of the impeller 50 via the gas pipe 40 fastened to the shaft 23.

[0043] As shown in Fig. 10, the second pipe 83 also includes a valve 83a capable of adjusting the internal pressure and a flow meter 83b capable of detecting the internal flow rate. The valve 83a can be operated by an operator. The flow meter 83b can be visually observed by an operator. The second pipe 83 is connected to the second hollow portion 67a at the base end (upper end) of the lance pipe 65. Therefore, the inert gas can be blown out from the gas hole 68b in the cover member 68 at the tip of the lance pipe 65.

[0044] As shown in FIG. 10, the third pipe 84 includes a third pipe 84 (upstream side) and a third pipe 84 (downstream side). The third pipe 84 (upstream side) 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 can be operated by an operator. The flow meter 84b can be visually observed by an operator. The third pipe 84 (upstream side) is connected to the tip of the housing 74 of the flux feeder 70. The third pipe 84 (downstream side) is connected from the outlet 75 of the housing 74 to the first hollow portion 66a at the base end (upper end) of the lance pipe 65. Therefore, the flux and the inert gas can be blown out from the outlet 68a of the cover member 68 at the tip of the lance pipe 65.

[0045] Next, the operation of the aluminum alloy molten metal treatment apparatus 1 will be described. First, the molten metal 3 melted in the melting furnace is poured into the treatment 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 so that the flux has a weight percent concentration of 0.2% relative to the molten metal 3. For example, 2 kg of flux is added to 1,000 kg of molten metal 3.

[0046] Next, the valve (not shown) of the gas cylinder 80 is opened. Next, the valves 82a to 84a of the first pipe 82 to the third pipe 84 are opened. At this time, the pressure inside the first pipe 82 to the third pipe 84 is adjusted so that the flow rate indications of the flow meters 82b to 84b of the first pipe 82, the second pipe 83, and the third pipe 84 have a ratio of, for example, 1:1:2, that is, the opening degree of the valves 82a to 84a is adjusted.

[0047] For example, if the flow rate of the inert gas discharged from the gas cylinder 80 is 0.4 m, the openings of the valves 82a to 84a are adjusted so that the flow rates inside the first pipe 82, the second pipe 83, and the third pipe 84 become 0.1 m, 0.1 m, and 0.2 m, respectively. As a result, as shown in FIG. 10 , the inert gas flows from the gas cylinder 80 to the main pipe 81, the first pipe 82, the hollow portion 24 of the shaft 23, the hollow portion 41 of the gas pipe 40, and the outlet hole 53 of the impeller 50 in this order. The inert gas is then discharged from the outlet hole 53 of the impeller 50. That is, the inert gas is blown into the molten metal 3.

[0048] 8 and 10, the inert gas flows from the gas cylinder 80 through the main pipe 81, the second pipe 83, the second hollow portion 67a of the lance pipe 65, and the gas hole 68b of the cover member 68 in this order. The inert gas is then discharged from the gas hole 68b of the cover member 68. In other words, the inert gas is blown into the molten metal 3.

[0049] 8 and 10, the inert gas flows from the gas cylinder 80 through the main pipe 81, the third pipe 84 (upstream side), the tip of the casing 74, the third pipe 84 (downstream side), the first hollow portion 66a of the lance pipe 65, and the outlet 68a of the cover member 68 in this order. Then, the inert gas is discharged from the outlet 68a of the cover member 68.

[0050] At this time, as already explained, the flux is discharged from the outlet 75 of the housing 74 of the flux feeder 70. Therefore, the flux flows together with the inert gas into the third pipe 84 (downstream side), the first hollow portion 66a of the lance pipe 65, and the outlet 68a of the cover member 68. That is, the inert gas is blown into the molten metal 3, and the flux is stably added.

[0051] When the flux is stably added to the molten metal 3, the added flux reacts with the oxides in the molten metal 3 as it floats in the molten metal 3. This separates the oxides from the molten metal 3, and the separated oxides float to the surface of the molten metal 3. Therefore, the floated oxides can be collected. In other words, the oxides in the molten metal 3 can be removed.

[0052] Furthermore, since the lance pipe 65 has a double structure, the periphery of the first hollow portion 66a through which the flux flows is covered by the second hollow portion 67a through which only the inert gas flows. Therefore, the inert gas flowing in the second hollow portion 67a blocks the heat transferred from the molten metal 3 to the flux. Next, after the addition of the predetermined amount of flux is completed, the motor 31 is driven to rotate the impeller 50 together with the gas pipe 40.

[0053] Even when the gas pipe 40 and the impeller 50 rotate, the baffle plate 61 prevents a vortex S from being generated around the axis of the gas pipe 40 in 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 there is no risk of new oxides being generated on the surface of the molten metal 3. As a result, there is no risk of new oxides being generated in the molten metal 3. In addition, the rotation of the gas pipe 40 and the impeller 50 stirs the molten metal 3. Therefore, the added flux is distributed throughout the molten metal 3. Therefore, the flux reacts with the oxides in the molten metal 3 without any leakage, and it is possible to prevent oxides in the molten metal 3 from being left behind.

[0054] 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 provided in a position where the vortex S of the molten metal 3 generated by these rotations is blocked by the baffle plate 61 (see FIGS. 2 and 9). Therefore, even if a vortex S is generated in this way, the baffle plate 61 blocks the generated vortex S so that it does not directly hit the lance pipe 65.

[0055] Furthermore, because the diameter of the impeller 50 is large (for example, about 300 mm), the inert gas injected into the molten metal 3 can be spread (distributed throughout) within the molten metal 3 even if the rotation speed of the gas pipe 40 remains low (even if the rotation speed of the gas pipe 40 is reduced). Furthermore, 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 on the molten metal surface after the oxide film has cracked. Furthermore, 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. Therefore, the effect of rubbing against the molten metal 3 is reduced, and wear on the shaft, gas pipe 40, impeller 50, and baffle plate 61 can also be reduced.

[0056] The hydrogen in the molten metal 3 dissolves in the bubbles generated by the inert gas blown into the molten metal 3. Then, the bubbles with dissolved hydrogen rise to the surface of the molten metal 3. Therefore, the hydrogen dissolved in the molten metal 3 is released into the atmosphere from the rising bubbles. In other words, the hydrogen in the molten metal 3 can be removed (degassed). Because the 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.

[0057] Furthermore, the bubbles generated by the inert gas injected into the molten metal 3 become fine 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. Therefore, a large amount of hydrogen in the molten metal 3 can be dissolved in the bubbles.

[0058] Furthermore, bubbles generated by the inert gas discharged from the outlet 68a of the lid member 68 flow in the radial direction of the impeller 50 due to the centrifugal force generated by the rotation of the impeller 50. At this time, bubbles that have entered the long grooves 55 of the impeller 50 come into contact with (are cut by) the long grooves 55 and become finer bubbles. Therefore, as described above, the total surface area of ​​the bubbles in the molten metal 3 also increases. Therefore, more hydrogen in the molten metal 3 can be dissolved in the bubbles.

[0059] Furthermore, the bubbles that have become finer by coming into contact with the long grooves 55 further enter the short grooves 57 of the impeller 50. Therefore, the fine bubbles that have entered the short grooves 57 move (are blown away) radially outward by the centrifugal force of the impeller 50. This allows the bubbles generated by the inert gas to spread further within the molten metal 3. This makes it possible to remove hydrogen from the molten metal 3 over a wide area.

[0060] The molten aluminum alloy processing apparatus 1 according to the embodiment is configured as described above. According to this configuration, the molten aluminum alloy processing apparatus 1 includes a flux feeder 70 that supplies flux by rotating a spiral blade 77. The molten aluminum alloy processing apparatus 1 further includes a gas pipe 40 having an outlet 40a at its end for blowing out an 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.

[0061] Therefore, even when the gas pipe 40 rotates together with the impeller 50, the baffle plate 61 prevents the formation of a vortex S around the axis of the gas pipe 40 within the molten metal 3. Therefore, the oxide film formed on the surface of the molten metal 3 is not likely to crack around the gas pipe 40, and new oxides are not likely to form on the surface of the molten metal 3. As a result, new oxides are not likely to form within the molten metal 3. Furthermore, because the flux is supplied by the rotation of the spiral blade 77, the supply of flux is stable. Therefore, for example, when flux is poured from the hopper 78 into the housing 74, there is no risk of the flux clogging the bottom of the hopper 78, or when a large amount of flux is poured from the hopper 78 into the housing 74 and the pressure-fed flux clogging the inside of the lance pipe. Therefore, flux can be stably added to the molten metal 3. As a result, oxides within the molten metal 3 can be removed. Furthermore, the inert gas blown out from the blowout holes 40a of the gas pipe 40 is stirred into the molten metal 3 by the impeller 50, so that hydrogen in the molten metal 3 can be removed.

[0062] Furthermore, with this configuration, the lance pipe 65 is disposed in a position where the vortex S of the molten metal 3 generated by the rotation of the impeller 50 is blocked by the baffle plate 61. Therefore, even if a vortex S of the molten metal 3 is generated by the rotation of the impeller 50, the generated vortex S is blocked by the baffle plate 61. Therefore, there is no risk that the generated vortex S will directly hit the lance pipe 65. Therefore, deformation of the lance pipe 65 can be suppressed.

[0063] Furthermore, according to this configuration, the aluminum alloy molten metal treatment apparatus 1 has a frame body 10 that rotatably holds the gas pipe 40. The frame body 10 has a motor 31 that is mounted to the frame body 10 and rotates the gas pipe 40 about its axis. The baffle plate 61 and the lance pipe 65 are held by the frame body 10. Therefore, there is no risk of the baffle plate 61 being displaced by a vortex S of the molten metal 3 that is generated by the rotation of the impeller 50. The same applies to the lance pipe 65. Therefore, the position of the lance pipe 65 relative to the baffle plate 61 can be maintained in an appropriate state.

[0064] Furthermore, with this configuration, the discharge port 66b of the lance pipe 65 is located above the impeller 50. Therefore, the impeller 50 stirs the molten metal 3 below the sprayed (added) flux. Therefore, the flux can be stirred efficiently.

[0065] Furthermore, according to 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 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. Therefore, the inert gas flowing between the small diameter pipe 66 and the large diameter pipe 67 blocks the heat transferred from the molten metal 3 to the flux. This reduces the risk of the flux melting inside the lance pipe 65 due to the heat transferred from the molten metal 3. This therefore reduces clogging of the lance pipe 65 with flux.

[0066] Although the embodiments have been described with reference to the above structures, it will be apparent to those skilled in the art that many alternatives, improvements, and modifications are possible without departing from the scope of the present invention. Therefore, the embodiments may include all alternatives, improvements, and modifications that do not depart from the spirit and scope of the appended claims. For example, the embodiments are not limited to a particular structure and may be modified as follows. Furthermore, the numerical values ​​disclosed in the embodiments may also be modified as appropriate.

[0067] In the embodiment, an example has been described in which 16 long grooves 55 are formed at equal intervals (in this example, at intervals of 22.5°) 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.

[0068] In the embodiment, the lance pipe 65 has been described as having a double structure including 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 including a medium diameter pipe 64 between the small diameter pipe 66 and the large diameter pipe 67 (see FIG. 11 ). In this case, an air layer or refractory material is inserted into a third hollow portion 64a between the medium diameter pipe 64 and the small diameter pipe 66, and an inert gas is flowed into a second hollow portion 67a between the medium diameter pipe 64 and the large diameter pipe 67.

[0069] With this triple structure, the heat transferred from the molten metal 3 to the flux is shielded by the inert gas flowing in the second hollow portion 67a and the air layer or refractory material in the third hollow portion 64a. This further reduces the risk of the flux melting inside the lance pipe 65 due to the heat from the molten metal 3. This further reduces clogging of the lance pipe 65 with flux.

[0070] In this triple structure, the small diameter pipe 66 is, for example, a 1-minute pipe, the medium diameter pipe 64 is, for example, a 3-minute pipe, and the large diameter pipe 67 is, for example, a 6-minute pipe. Also, the small diameter pipe 66 may be, for example, a 2-minute pipe, the medium diameter pipe 64 may be, for example, a 5-minute pipe, and the large diameter pipe 67 may be, for example, a 1-inch pipe.

[0071] Furthermore, as described above, the lance pipe 65 is not limited to a double or triple structure, and any number of layers may be used as long as the lance pipe 65 has a multiple-layer structure. For example, the lance pipe 65 may have a quadruple structure. In this case, as with the triple structure, an air layer or a layer into which a refractory material is inserted is added. Of course, instead of the air layer or the layer into which a refractory material is inserted, a layer into which an inert gas flows may be added. In other words, any layer may be used as long as it provides thermal insulation.

[0072] In the embodiment, the impeller 50 is made of silicon nitride, but the impeller 50 is not limited to this material. The impeller 50 may be made of graphite.

[0073] In the embodiment, the pressure inside the first pipe 82 to the third pipe 84 is adjusted so that the flow rate indicated by the flow meters 82b to 84b of the first pipe 82, the second pipe 83, and the third pipe 84 has a ratio of, for example, 1:1:2. That is, the aperture of the valves 82a to 84a is adjusted. However, without being limited to this, the pressure inside the first pipe 82 to the third pipe 84 may be adjusted so that the flow rate indicated by the flow meters 82b to 84b has a ratio of 2:1:4. That is, the aperture of the valves 82a to 84a may be adjusted. In this case, for example, if the flow rate of the inert gas discharged from the gas cylinder 80 is 3.5 m, the aperture of the valves 82a to 84a is adjusted so that the flow rates inside the first pipe 82, the second pipe 83, and the third pipe 84 have a ratio of 1 m, 0.5 m, and 2 m. Various ratios for the flow rate indications may be considered and are determined appropriately. [Explanation of symbols]

[0074] 1. Aluminum alloy molten metal treatment equipment 3 Molten metal 10 Frame body (base) 31 Motor 40 Gas Pipe 50 impeller 53 Air outlet 61 Baffle plate 65 Lance Pipe 66 Small diameter pipe 66b Outlet 67 Large diameter pipe 70 Flux Feeder 77 Spiral Blade (Screw) S vortex

Claims

1. An aluminum alloy molten metal treatment apparatus, a flux feeder that supplies flux by rotating a screw; a gas pipe having an outlet hole at an end thereof for blowing out an inert gas; an impeller that protrudes radially from the vicinity of the end of the gas pipe and rotates together with the gas pipe; a baffle plate adjacent to the impeller; a lance pipe having a discharge port for discharging the flux supplied from the flux feeder, an end of the flux feeder that supplies the flux is provided with piping through which the inert gas is supplied from the same source as the inert gas blown out from the blowing hole of the gas pipe.

2. The aluminum alloy molten metal treatment apparatus according to claim 1, The lance pipe is disposed in a position where a vortex of the molten metal generated by the rotation of the impeller is interrupted by the baffle plate.

3. The aluminum alloy molten metal treatment apparatus according to claim 2, a base that rotatably holds the gas pipe; a motor provided on the base for rotating the gas pipe about an axis; The baffle plate and the lance pipe are held by the base.

4. The aluminum alloy molten metal treatment apparatus according to any one of claims 1 to 3, The aluminum alloy molten metal treatment apparatus, wherein the discharge port of the lance pipe is located above a lower end of the impeller.

5. The aluminum alloy molten metal treatment apparatus according to any one of claims 1 to 3, the lance pipe has a small diameter pipe and a large diameter pipe through which the small diameter pipe is inserted, the flux is caused to flow through the small diameter pipe, the inert gas is caused to flow between the small diameter pipe and the large diameter pipe, and the flux and the inert gas are discharged from the discharge port.

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