JP2018015791A - Manufacturing apparatus of metal molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus of a metal molding using electromagnetic stirring of molten metal, capable of stirring efficiently even when using a slender mold, and suppressing running on or running over to a wall surface of a mold of the molten metal.SOLUTION: In a manufacturing apparatus 10 of a metal molding including a mold 11 having a slender planar shape, and a plurality of pairs of thrust units 12 arranged along a wall surface 16 so as to sandwich the mold from both sides, the pair of thrust units has an electromagnetic coil 14 generating a progressive magnetic field in mutually reverse directions, and each thrust unit 12 adjacent in the longer direction generates a progressive magnetic field in mutually reverse directions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal molded body manufacturing apparatus. More particularly, the present invention relates to an apparatus for producing a tough metal molded body by electromagnetically stirring a metal such as a molten aluminum alloy to suppress the growth of metal crystals and cooling while discharging a residual gas which is a source of a nest.

  A description will be given taking aluminum as an example of the metal. In order to make precision aluminum equipment, it is essential that the material aluminum has a fine crystal structure and no defects such as nests inside. In order to make such a material, molten aluminum is transferred to a mold of a stirrer (metal molded body manufacturing apparatus), and stirring and cooling are performed in the mold, thereby preventing growth of the crystal structure and making the material dense. Although a mechanical force may be used as the stirring force, an electromagnetic force method capable of stirring in a non-contact manner is preferable in consideration of wear of the stirring rod.

  In order to stir by electromagnetic force, a large number of coils are arranged along the wall surface of the mold (indicating the inner wall surface), and a magnetic field traveling along the wall surface is formed by these coil groups. Then, an electric current is generated in the molten aluminum by the traveling magnetic field, an electromagnetic force is generated by the electric current and the changing magnetic field, and the molten metal moves along the wall surface. Then, the movement of the molten metal along the wall surface reaches the center, and the stirring is advanced as a whole. This stirring operation is continued until the metal solidifies. Next, the solidified metal may be used as a final molded body as it is, or may be transferred to a press mold and pressed and molded. The aluminum equipment made in this way is strong and has few defects such as nests. For this reason, it is a powerful component equipment.

  Generally, as described in Patent Documents 1 to 3, an aluminum stirring furnace stirs a melt with a cylindrical crucible. For this reason, the electromagnetic stirrer is cylindrical and is like a motor stator. However, for example, when an elongated structure is made of aluminum, the shape of the stirring type becomes long and thin, and the cylindrical stirring furnace has a huge volume and requires a large exciting force, which is unreasonable. For this reason, a linear (linear) stirring device as in Patent Document 4 is known.

  Further, Patent Document 5 and Non-Patent Documents 1 and 2 are known as the structure of the thrust portion of the linear stirring device.

Japanese Patent No. 5352236 JP 2009-74103 A JP 2007-144501 A JP 2006-289448 A JP 2006-289476 A

Nippon Steel Technical Report No. 379 “Electromagnetic coil design by electromagnetic fluid analysis” Furuka-sky Review No. 3 2007 "Development of electromagnetic stirring simulation in melting furnace"

  Car body structures are generally thin and long. Moreover, there are many things that are bent. Therefore, the circular agitator is difficult to cope with because the furnace volume increases as described above, and the excitation force (AT) for operation increases. Therefore, a linear type (linear type) agitator as in Patent Documents 4 and 5 relating to a continuous casting apparatus is applied. However, the linear stirrer has an elongated structure and a long acceleration distance (see FIG. 1). If the acceleration distance is long as described above, the speed of the molten metal increases, and the molten metal rides on the wall surface of the mold at the folded portion (see the end portion 18 in FIG. 1) having a small radius of curvature, or spills outside through the wall surface. A phenomenon occurs. In particular, the mold is provided with a draft, making it easier to get on.

  If the excitation force is reduced in order to suppress such a phenomenon of overcoming, the agitation efficiency is lowered while the overcoming is suppressed, but the stirring efficiency is reduced, and a metal molded body made of fine crystals cannot be efficiently produced. . The present invention solves such problems, and provides a metal molded body manufacturing apparatus that can efficiently stir even when an elongated mold is used, and that can prevent the molten metal from climbing on and over the mold wall surface. Is a technical issue.

  An apparatus for producing a metal molded body according to the present invention includes a mold having an elongated planar shape, and a plurality of pairs of thrust units arranged along a wall surface so as to sandwich the mold from both sides, and the pairs of thrust units are mutually connected. It has an electromagnetic coil that generates a traveling magnetic field in the reverse direction, and the thrust units arranged in the longitudinal direction are set so as to generate a traveling magnetic field in the reverse direction for each one or for a plurality of stations. It is characterized by being.

  Such a metal molded body manufacturing apparatus includes a control circuit that switches the traveling magnetic field of the electromagnetic coil so that the thrust units arranged in the longitudinal direction generate a traveling magnetic field in the reverse direction for each desired number. It may be a thing. Moreover, the whole or a part of the mold may be curved in a planar shape. In addition to a thrust unit that provides a traveling magnetic field in the horizontal direction, it is preferable to include a thrust unit that provides a traveling magnetic field in an oblique vertical direction.

In the apparatus for producing a metal molded body of the present invention, a partial molten metal circulation flow is generated in a mold by a continuous traveling magnetic field composed of a pair of thrust units or a plurality of pairs of thrust units arranged along a wall surface across the mold. Can be made. That is, a flow in one direction is generated by one or more thrust units arranged along one wall surface, and a flow in the other direction is generated by one or more thrust units arranged along the other wall surface. And the flow of the direction crossing a type | mold arises in the edge part of each series. Therefore, a flow that circulates for each thrust unit is generated. And since the direction of a magnetic field progress is reverse in the thrust unit of a certain series and the thrust unit of the other series adjacent to it, the direction of a circulation flow is reversed. For example, when a clockwise circulating flow is generated in a pair of thrust units, a counterclockwise circulating flow is generated in another pair of adjacent thrust units.

  Accordingly, at the end of the thrust unit, the flow along the wall surface is divided, so to speak, a node is formed in the flow. Therefore, the accelerated flow decelerates at the node portion, and the energy of movement is converted into the energy of stirring. Therefore, the climbing on the wall surface and the climbing over the wall surface are suppressed. In addition, at the node portion, the molten metal flowing from both sides collides or flows, so that the molten metal is stirred more efficiently.

  In such a metal molded body manufacturing apparatus, a control circuit for switching the direction of the traveling magnetic field of the electromagnetic coil is provided so that the thrust units arranged in the longitudinal direction generate a traveling magnetic field in the reverse direction for each desired number. If it is, an appropriate stirring action and flow rate can be selected according to the type of metal. Further, when the mold is curved in a planar shape, a curved metal molded body can be produced efficiently, and the above-described ride-up and overcoming suppression can be achieved as described above.

  In addition to the thrust unit that provides a horizontal traveling magnetic field, if a thrust unit that provides an oblique longitudinal traveling magnetic field is provided, the laminar flow is commutated because the molten metal flows diagonally, and stirring is performed more efficiently. And crystal grains can be made fine.

FIG. 1a is a plan view showing an embodiment of a metal molded body manufacturing apparatus of the present invention, and FIG. 1b is an enlarged view of a main part thereof. It is the II-II sectional view taken on the line of the manufacturing apparatus of FIG. FIGS. 3a and 3b are a schematic plan view and a schematic side view, respectively, showing an embodiment (core back-circulation system) of a thrust unit according to the present invention. 4a and 4b are a schematic plan view and a coil connection diagram showing another embodiment (slot winding system) of the thrust unit according to the present invention, respectively. It is a top view which shows an example of a connection when combining several thrust units of FIG. 3a and FIG. 3b. It is a top view which shows other embodiment of the metal molded object manufacturing apparatus of this invention. 7a and 7b are a front view and a plan view, respectively, showing an embodiment of a thrust unit for changing the flow of molten metal according to the present invention (coil side shape illustration is omitted). 8a to 8d are plan views showing still other embodiments of the metal molded body production apparatus of the present invention.

  A metal molded body manufacturing apparatus (electromagnetic stirrer) 10 shown in FIG. 1a includes an elongated mold 11 that is curved in an arc shape in a plan view, and a plurality of pairs arranged along the mold wall surface so as to sandwich the mold. The thrust unit 12 is provided. The thrust unit 12 includes a core 13 and a coil 14 wound around the core 13 as shown in FIG. 1b. In this embodiment, two sets of three coils 14 wound around one core 13 are connected at an angle via a wedge-shaped magnetic body 15 for curvature adjustment to form one unit. In FIG. 1a, the wedge-shaped magnetic body is omitted.

  For example, as shown in FIG. 2, the mold 11 has a substantially U-shaped cross section including a bottom plate 16 and side walls 17 rising from both ends of the bottom plate. Usually, the depth of the mold 11 is deeper than the width. Further, the side wall 17 is provided with a draft angle and expands toward the upper end. The mold 11 is formed of a metal (for example, stainless steel), ceramics, etc. having heat resistance that can withstand the high temperature of the molten metal and having low magnetic permeability. The thrust unit 12 is disposed obliquely so as to be parallel to the wall surface with a slight gap G between the tilted side wall 17 and the wall surface (inner wall surface) of the inclined side wall 17.

  The dimensions and shape of the mold 11 depend on the size and shape of the member to be molded. As shown in FIG. 1a, the end 18 of the mold 11 is arcuate so that the molten metal can be smoothly turned. In this embodiment, the left and right side walls 17 are each curved. The left and right side walls 17 share the same center of curvature and have substantially the same width over the length direction. Similarly, the thrust unit 12 arranged along the side wall 17 is also curved or bent, and the gap G (see FIG. 2) with the side wall (inner side wall) 17 is as small as possible and along the longitudinal direction. Is constant.

  FIGS. 3 a and 3 b show the “core back turning method” among the basic shapes of the thrust unit 12. The thrust unit 12 includes a comb-like core 13 and a coil 14 wound between the teeth of the core. The core 13 includes a prismatic yoke (core spine) 19 and a tooth 21 having one end fixed to a dovetail groove 20 formed in the yoke. There are seven teeth 21, and there are six coils 14 wound around the yoke between them, and they are all wound in the same direction. Therefore, the polarity is reversed between when the current enters from the winding start coil and when the current enters from the winding end coil. The slot 22 between the teeth 21 is filled with a coil (coil conductor) 14. The slot 22 opens on the mold 11 side through a slit 23 that is an elongated opening. The yoke 19 and the teeth 21 are each composed of a core in which a large number of thin silicon steel plates are stacked. The yoke and teeth may be integrated.

  The thrust unit 12A shown in FIGS. 4A and 4B shows the “inter-slot circulation method” among the basic shapes. This system includes a comb-like core 13 composed of a yoke 19 and a plurality of teeth 21 and a coil 14 wound around the plurality of teeth 21. The slots 22 a to 22 f are filled with a coil (coil conductor) 14. The coil 14 includes three types of coils 14u, 14v, and 14w that respectively correspond to the U-phase, V-phase, and W-phase of the three-layer AC. For example, the U-phase coil 14u is passed between the leftmost slot 22a and the fourth slot 22d and wound around three teeth therebetween.

  Similarly, the V-phase coil 14v is passed between the third and sixth slots 22c and 22f and wound around three teeth therebetween. The W-phase coil 14w is passed through the second slot 22b and the fifth slot 22e and wound around three teeth therebetween. These three types of coils 14u, 14v, and 14w intersect each other on the side of the core 13 as shown in FIG. 4b. A symbol O is a neutral point of the three-phase alternating current. In such an “inter-slot circulation type” propulsion unit 12A, the coils 14u to w do not circulate around the core spine 19, so that the core spine 19 can be used to fix the thrust unit.

  FIG. 5 shows three thrust units 12 arranged on one side of the mold 11 and connected. The power supply is a three-phase alternating current. The symbol O is a neutral point. When three-phase alternating currents U, W, and V are sequentially connected to the coils of terminal symbols R, S, and T, the magnetic flux advances from the left to the right (see arrow φ1). When the phase order is changed and the connections are made in the order of U, V, and W phases, the magnetic flux advances from the right to the left (in the direction of arrow φ2). That is, in FIG. 5, in the leftmost unit 12a, the W phase is connected to the end of winding of the coil indicated by reference numeral w1- and the V phase is connected to the beginning of winding of the coil indicated by reference numeral v1 +. The V phase is connected to the winding end of the w3-coil, and the W phase is connected to the winding start of the v3 + coil. The V phase and the W phase are reversed. Further, since the right end unit 12c is connected in the same manner as the left end unit 12a, the magnetic flux advances in the direction of the arrow φ3 similar to the arrow φ1.

When such thrust units are arranged on both sides of the pot, as shown in FIG. 6, the magnetic flux traveling directions of the units 12a, 12b, 12c on the front side of the mold 11 and the units 12d, 12e, 12f on the other side are reversed. To. As a result, when the direction of the molten metal vortex flow Q1 provided by the leftmost unit pair 12a, 12d is counterclockwise, the central unit pair 12b, 12e has a clockwise vortex flow Q2, and further the right bridge unit In the pair 12c and 12f, the counterclockwise vortex flow Q3 is generated again.

  Therefore, since the direction of the vortex flowing in each adjacent unit is reversed, the flow along the wall surface is divided at the end of the thrust unit, so that nodes 24a and 24b are formed in the flow. Therefore, the accelerated flow decelerates at the nodes 24a and 24b, and the energy of movement is converted to the energy of stirring. Therefore, even when the end portion flows in an arcuate shape or when the side wall 17 is curved as shown in FIG. 1a, the climbing of the side wall 17 onto the wall surface and the overcoming of the side wall 17 are suppressed. Moreover, in the part of the node 24a and the node 24b, the molten metal which flows from both sides collides, and furthermore, the integrated flow is divided, so that the molten metal is stirred more efficiently.

  In the above embodiment, the thrust units are arranged in parallel with the inner wall of the mold (meaning that the air gap is uniform), and the vortex flow is generated in the horizontal direction. For example, as shown in FIG. 7a and FIG. It is also possible to combine with the thrust unit 25 that generates the flow P. The two slots 22 of the thrust unit 25 are formed with slits 23 having an inclination angle (skew) that recedes downward. Due to such skew, an oblique flow P in the vertical direction is generated in the molten metal, and the laminar flow of the molten metal in the mold is commutated, so that the residual gas can be easily removed and the stirring is performed more efficiently. Can be made fine.

  Such a skew can be formed by processing the slits 23 obliquely when laminating electromagnetic steel plates and machining the slots 22 by wire cutting. The slot 22 is filled with a coil (coil conductor) 14, but is omitted in FIG. 7b. Reference numeral 26 in FIG. 7 b denotes a sashiki that holds the coil 14 in the slot 22.

  In the above-described embodiment, since the traveling direction of the magnetic field is reversed for each thrust unit 12, the directions of the molten metal vortices Q1 and Q2 are reversed for each pair of thrust units 12 as shown in FIG. 8a. However, two or three as shown in FIG. 8b or 8c, or four or more propulsion units as shown in FIG. 8d form a “ream” in which the traveling direction of the magnetic field is the same. It can also be installed. In these cases, the number of nodes is reduced, so that the stirring action is reduced, but the speed of the vortex is increased. Therefore, an appropriate stirring action and vortex velocity can be set according to the type of metal to be manufactured.

  In addition, a control circuit that switches the direction of the current flowing through the electromagnetic coil of the thrust unit for each thrust unit is provided, and the direction of the traveling magnetic field for every N propulsion units, such as one thrust unit, two thrust units, etc. May be changed so that the direction of the vortex can be reversed. In such a metal molded body manufacturing apparatus that can change the coil wiring of the thrust unit, an appropriate stirring action and vortex velocity can be selected according to the type of metal, and the metal molded body can be efficiently manufactured. Can do.

DESCRIPTION OF SYMBOLS 10 Metal forming body manufacturing apparatus 11 Type | mold 12 Thrust unit 12A Thrust unit 13 Core 14 Coil 15 Wedge-like magnetic body 16 Bottom plate 17 Side wall G Gap 18 End part 19 Yoke (core back)
20 Groove 21 Teeth 22 Slot 23 Slit 22a-f Slot 14u, 14v, 14w Coil U, V, W Three-phase AC phase symbol u1-5, v1-5, w1-5 Coil R, S, T Three-phase AC Terminal symbol O Neutral point φ1, φ2, φ3, φ4, φ5, φ6 Magnetic flux traveling direction P Indicates the direction of molten metal flow 12a-c, 12d-f Thrust unit 14u, 14v, 14w Coils 24a, 24b Section 25 Thrust unit that creates inclined flow Q1, Q2, Q3 Eddy current 26 Sashiki

Claims (4)

  A planar shape is an elongated mold and a plurality of pairs of thrust units arranged along the wall surface so that the mold is sandwiched from both sides, and the pair of thrust units has electromagnetic coils that generate traveling magnetic fields in opposite directions. An apparatus for manufacturing a metal molded body, wherein the thrust units arranged in the longitudinal direction are set so as to generate a traveling magnetic field in the reverse direction for each or a plurality of stations.   2. The metal molded body according to claim 1, further comprising a control circuit for switching the direction of the traveling magnetic field of the electromagnetic coil so that the thrust units arranged in the longitudinal direction generate a traveling magnetic field in the reverse direction for each desired number. apparatus.   The metal molded body manufacturing apparatus according to claim 1 or 2, wherein the whole or part of the mold is curved in a planar shape.   The metal molded body manufacturing apparatus according to any one of claims 1 to 3, further comprising a thrust unit that provides an oblique longitudinal magnetic field in addition to a thrust unit that provides a horizontal traveling magnetic field.

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