JP5946874B2 - Temperature control mechanism for molten metal in ladle in automatic casting machine - Google Patents

Description

  In the present invention, for example, in automatic casting using a die casting machine for producing a cast product made of aluminum alloy or the like, a molten metal is pumped by a ladle from a melting holding furnace to a cup accommodated in an electromagnetic stirring device for forming a semi-solid slurry. Automatic casting that enables hot-water temperature control and management when hot water is supplied and then formed into a semi-solid slurry with a low-viscosity semi-solid structure, and the semi-solid slurry is fed into the injection sleeve of a die casting machine. The present invention relates to a melt temperature adjustment mechanism in a ladle in an apparatus.

  Conventionally, a die casting machine in an automatic casting apparatus is composed of at least two members, a fixed mold provided on a fixed die plate and a movable mold provided on a movable die plate so that the cast die cast can be taken out. By combining the mold and the movable mold, a predetermined cast product is formed by semi-solid slurry or molten metal into a form corresponding to the shape in both molds. An injection sleeve is provided on the fixed mold side, and a plunger having an injection tip at the tip slides back and forth in the injection sleeve to inject semi-solid slurry, molten metal, and the like. .

  When casting with the above-mentioned die casting machine, the mechanical properties are excellent, and a highly accurate product is molded by introducing a semi-solid slurry or molten metal having a low-viscosity semi-solid structure directly into the injection sleeve or using a cup. Therefore, conventionally, a semi-solid casting method using an electromagnetic stirring method is employed. In the conventional semi-solid casting method using an electromagnetic stirring method, first, a semi-solid slurry forming cup is cooled, cleaned and dried, and then a release agent is applied to the inner surface of the cup. And this cup is accommodated between the magnetic field generation | occurrence | production coils of an electromagnetic stirrer, and a molten metal is thrown into the said cup using a ladle from a melting holding furnace. Next, by applying a momentum to the molten metal by energizing the magnetic field generating coil and uniformly stirring the molten metal, the molten metal is changed to a highly viscous semi-solid slurry of a semi-solid structure. After the stirring, the cup is taken out from the electromagnetic stirring device, and the semi-solid slurry in the cup is put into the injection sleeve from the charging port provided in the injection sleeve to prepare for subsequent molding.

  However, in the casting method using the conventional die casting machine, when the molten metal is pumped up by a ladle from the melting holding furnace and the molten metal in the ladle is put into a cup accommodated between the magnetic field generating coils of the electromagnetic stirring device, the molten metal is Since the contact time with air is long, a nest is generated due to the entrapment of air, impurity gas, or the like in the product, which leads to defects such as insufficient strength and cracks. For this reason, it is important to manage the temperature of the molten metal in the ladle immediately before the molten metal is poured into the cup accommodated in the electromagnetic stirring device.

  Further, when molten metal is introduced into a cup of an electromagnetic stirring device using a ladle, a refined semi-solid structure is formed by this alloy crystal unless the molten metal is introduced at a temperature set in advance depending on the type of alloy. I can't. For example, in the case of an alloy having a melting temperature of 640 ° C., a uniform semi-solid slurry cannot be formed unless it is introduced at a temperature of 620 ° C., which is 20 degrees lower than this, and a high-quality cast product cannot be obtained in casting using the die casting machine. . This is a characteristic of empirical semi-solid thixotropy that the hardened phase enters the softened phase at a phase ratio of 6 (solid phase): 4 (liquid phase). For this reason as well, it is necessary to control the temperature of the molten metal in the ladle immediately before the molten metal is introduced into the cup accommodated in the electromagnetic stirring device using the ladle.

nothing special

  However, conventionally, the temperature of the molten metal in the ladle is measured immediately before the molten metal is poured into the cup accommodated in the electromagnetic stirrer using the ladle, and the temperature of the molten metal is controlled based on this measurement data. The idea was not made yet.

  Therefore, the present invention was created in view of the existing circumstances as described above, and a molten metal is introduced into a cup accommodated between magnetic field generating coils of an electromagnetic stirrer using a ladle so that a semi-solid slurry is formed. The formation of nests due to entrainment of air or impurity gas during formation and the generation of cracks can be prevented in advance, and uniform semi-solid slurry with a refined semi-solid structure can be easily and reliably formed. An object of the present invention is to provide a melt temperature adjustment mechanism in a ladle in an automatic casting apparatus that enables temperature control and management when a semi-solid slurry is supplied into an injection sleeve of a die casting machine and cast.

In order to solve the above-described problem, in the present invention, the automatic hot water supply device 3 that pumps the molten metal S from the melting holding furnace 1 by the ladle 4 and the molten metal S pumped by the ladle 4 of the automatic hot water supply device 3 are supplied. The cup 5 is housed between the magnetic field generating coils, and the electromagnetic stirrer 7 for molding the molten metal S in the cup 5 into a semi-solid slurry having a low-viscosity semi-solid structure by this electromagnetic force, and the cup 5 containing the semi-solid slurry. And a molten metal temperature adjustment mechanism 6 in a ladle of an automatic casting apparatus, which includes a moving mechanism portion 8 for feeding the material into an injection sleeve 12 penetratingly disposed on the fixed mold 15 side of the die casting machine 11. Measurement information of a ladle temperature measuring unit 6A that measures the molten S temperature in the ladle 4 immediately before the hot water is supplied, a temperature adjusting unit 2 that adjusts the furnace temperature of the melting and holding furnace 1, and measurement information of the ladle temperature measuring unit 6A The hot water supply temperature measurement which enabled temperature control by communication to the temperature adjustment part 2 in the melt holding furnace 1 after the standby or return operation of the ladle 4 by the automatic hot water supply device 3 and the return of the molten metal S in the ladle 4 based on And a control device 6B.
The ladle temperature measuring unit 6A may be a thermocouple thermometer / thermistor.

In the ladle molten metal temperature adjustment mechanism in the automatic casting apparatus according to the present invention configured as described above, the ladle molten metal temperature adjustment mechanism 6 includes a thermocouple thermometer and thermistor immediately before being fed into the cup 5. When the measurement information of the molten metal S temperature in the ladle 4 measured by the used ladle temperature measuring unit 6A becomes equal to or higher than a predetermined set temperature, for example, the ladle 4 is kept in the atmosphere until it decreases to the predetermined set temperature by natural heat dissipation. The automatic hot water supply device 3 is controlled so that the molten metal S in the ladle 4 falls below a predetermined set temperature, and the automatic hot water supply device 3 is returned so that the molten metal S in the ladle 4 is returned to the melting and holding furnace 1. To control.
In addition, the hot water temperature measurement control device 6 </ b> B determines that the temperature of the molten metal S is low by the ladle temperature measuring unit 6 </ b> A even if the molten metal S in the ladle 4 is returned about three times. The temperature adjustment unit 2 is remotely controlled by a communication signal from the melt temperature adjustment mechanism 6 in the ladle so that the temperature in the furnace increases.

  According to the present invention, the molten metal S is introduced into the cup 5 accommodated between the magnetic field generating coils of the electromagnetic stirrer 7 by using the ladle 4 and the semi-solid slurry is formed by entrainment of air, impurity gas, or the like. Generation of nests and occurrence of cracks can be prevented in advance, and a uniform semi-solid slurry can be easily and reliably formed by the refined semi-solid structure. The semi-solid slurry is formed into the injection sleeve 12 of the die casting machine 11. It enables temperature control during casting by feeding inside.

  That is, this is a ladle temperature measuring unit 6A that measures the melt S temperature in the ladle 4 immediately before the molten metal temperature adjusting mechanism 6 in the ladle 4 in the automatic casting apparatus according to the present invention supplies hot water into the cup 5, and a melting holding furnace. The temperature adjustment unit 2 that adjusts the temperature in the furnace 1 and the operation of standby or return of the ladle 4 by the automatic water heater 3 based on the measurement information of the ladle temperature measurement unit 6A and the melting after the return of the molten metal S in the ladle 4 This is because it has a hot water supply temperature measurement control device 6B that enables temperature control by communication with the temperature adjustment unit 2 in the holding furnace 1, so that, for example, when the temperature exceeds a predetermined set temperature, it is determined by natural heat dissipation. The ladle 4 is allowed to stand by in the atmosphere until the set temperature reaches the set temperature, and when the molten metal S temperature in the raddle 4 falls below a predetermined set temperature, the molten metal S in the ladle 4 is returned to the melting and holding furnace 1. After raising the temperature of the inner, by executing the pumping of the molten metal S by ladle 4 again, it is possible to reliably form a uniform semi-solid slurry by semi-solidified tissue finer electromagnetic stirring device 7.

  Since the ladle temperature measuring unit 6A uses a thermocouple thermometer / thermistor, it can accurately measure the molten S temperature in the ladle 4 immediately before being fed into the cup 5, and to the hot water temperature measuring control device 6B. The temperature measurement data can be transmitted accurately.

  Note that the reference numerals added in the means for solving the above-described problems and the effects of the invention are given for easy reference to the parts showing the components shown in the drawings. The present invention is not limited to the structure / shape indicated by the reference numeral.

It is a general | schematic perspective view which shows the whole structure of the automatic casting apparatus in one form for implementing this invention. It is a perspective view which similarly shows the measurement state of the molten metal temperature in a ladle by the ladle temperature measurement part of the molten metal temperature adjustment mechanism in a ladle. It is a block diagram which similarly shows the structure of the molten metal temperature adjustment mechanism in a ladle. It is a flowchart for demonstrating operation | movement of the molten metal temperature adjustment mechanism similarly in a ladle.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Reference numeral 1 shown in the figure is a melting and holding furnace in an automatic casting apparatus provided with a melt temperature adjusting mechanism 6 in a ladle. As shown in FIG. 1, the holding furnace 1 is formed of, for example, a barrel-shaped crucible container in which a heater H is wound in a coil shape. The heater H melts, for example, an aluminum alloy or the like, and controls the energization of the heater H. Therefore, the molten metal S can be held at a predetermined temperature by the temperature adjusting unit 2 disposed on the outer wall of the melting and holding furnace 1.

  An automatic hot water supply device 3 for pumping the molten metal S by the ladle 4 is installed in the vicinity of the melting and holding furnace 1. This automatic hot water supply device 3 is constituted by a hot water supply robot provided with an arm-like ladle drive unit 3A with a ladle 4 swingably mounted at the tip, and the base of the hot water supply robot is located in the vicinity of the melting and holding furnace 1. is set up. In the vicinity of the automatic hot water supply device 3, the temperature of the molten metal S in the ladle 4 immediately before being supplied into the cup 5 for forming a semi-solid slurry is measured, and the operation of the ladle 4 is controlled based on the measurement result. The electromagnetic stirring apparatus 7 provided with the melt temperature adjustment mechanism 6 in the ladle which concerns on is installed.

  The electromagnetic stirrer 7 is formed with a cylindrical opening-shaped accommodating portion 7a at the center, and a heat-resistant cup 5 having, for example, a half-elliptical shell shape is detachably accommodated and held therein. . And in the hot_water | molten_metal supply position of the cup 5, the molten metal S pumped up from the melting holding furnace 1 using the ladle 4 provided in the automatic hot-water supply apparatus 3 is supplied to the said cup 5 with hot water. The electromagnetic stirrer 7 stirs the molten metal S in a non-contact and uniform manner in a rotationally moving magnetic field and an axially moving magnetic field, for example, by rotating a permanent magnet.

  As a specific electromagnetic stirring device 7, a rotating magnetic field generating coil provided along the outer peripheral surface of the container that accommodates the cup 5 in order to cause the molten metal S to generate a rotational motion, and an axial motion of the molten metal S are generated. The axial moving magnetic field generating coil provided along the axial direction of the outer peripheral surface of the container that accommodates the cup 5 can be used in combination. As a result, a strong flow velocity motion in which the rotational motion and the axial motion are superimposed is generated in the molten metal S, and the molten metal S is strongly and uniformly stirred. In particular, since the electromagnetic stirring device 7 can form a large velocity gradient in the molten metal S, the aggregation and enlargement of inclusion particles in the molten metal S can be promoted and controlled. Thus, the ratio of the liquid phase to the solid phase can be freely changed by the energization time of the magnetic field generating coil, the frequency of the magnetic field, the electric power to be applied, and the like. It becomes possible to form a coagulated tissue.

  Next to the electromagnetic stirrer 7, there is provided a moving mechanism unit 8 for taking out the cup 5 from the electromagnetic stirrer 7 and supplying the semi-solid slurry into the injection sleeve 12 of the adjacent die casting machine 11. Adjacent to the moving mechanism 8 is a cup preparation device 41 for applying cleaning spray or the like to the empty cup 5 and preparing the cup 5 for the next operation, a product conveyor 51 for conveying the finished cast product, and the like. Has been.

  The temperature adjusting unit 2 in the melting holding furnace 1 described above is remotely controlled by a communication signal from the melt temperature adjusting mechanism 6 in the ladle, and the melting temperature in the furnace by the heater H is an arbitrary set temperature, for example, the melting temperature in the case of an aluminum alloy. The temperature is maintained at a substantially uniform temperature of 640 ± 5 ° C.

  Moreover, the above-described melt temperature adjustment mechanism 6 in the ladle is, as shown in FIG. 2, a hot water supply temperature measurement control device 6B installed at a corner near the housing portion 7a provided on the upper surface of the electromagnetic stirring device 7, A ladle temperature measuring unit 6A such as a thermocouple thermometer and a thermistor (heat sensitive part of a resistance thermometer) hanging from the side of the hot water temperature measuring control device 6B is configured.

  As shown in FIG. 1, the ladle driving unit 3A automatically measures the molten metal S measured by an instruction from the hot water supply temperature measurement control device 6B, for example, about 40 g, and in some cases, an arbitrarily large amount. Oscillation is controlled so as to be supplied to the cup 5 installed inside the accommodating portion 7a of the electromagnetic stirring device 7 installed in the vicinity of the hot water supply device 3.

  The melt temperature adjustment mechanism 6 in the ladle measures the temperature of the melt S in the ladle 4 in advance immediately before being fed into the cup 5 by the ladle temperature measuring unit 6A, and the automatic hot water supply is based on the measured temperature information. The temperature after the ladle drive unit 3A of the apparatus 3 waits in the atmosphere of the ladle 4 or returns the ladle 4 to the melting and holding furnace 1 side, and the temperature after the molten metal S in the ladle 4 is returned to the melting and holding furnace 1 Temperature control in the melting and holding furnace 1 by the adjusting unit 2, particularly temperature rise control in the furnace is enabled.

  For example, the temperature measurement result of the molten metal S in the ladle 4 measured immediately before the hot water is fed into the cup 5 is equal to or higher than a predetermined set temperature necessary for forming a refined semi-solid structure, for example, an aluminum alloy. When the temperature becomes 620 ° C. or higher, the ladle driving unit 3A is controlled so that the ladle 4 is kept in the air until it reaches a predetermined set temperature by natural heat dissipation. Conversely, when the temperature of the molten metal S in the ladle 4 is equal to or lower than a predetermined set temperature, for example, 620 ° C. or lower for an aluminum alloy, the ladle drive unit is returned so that the molten metal S in the ladle 4 is returned to the melting and holding furnace 1. 3A is controlled. In addition, the ladle temperature measuring unit 6A sends a signal to the temperature adjusting unit 2 to raise the in-furnace temperature of the melting and holding furnace 1, and then pumps the molten metal S of the melting and holding furnace 1 by the ladle 4 at the tip of the ladle driving unit 3A. The ladle driving unit 3A of the automatic hot water supply device 3 is controlled to resume.

  The ladle temperature measuring unit 6A is inserted and fixed in the ladle 4 in order to eliminate the time lag of the insertion operation of the ladle temperature measuring unit 6A immediately before the hot water is supplied to the cup 5 by the ladle 4 of the automatic water heater 3. Thus, the temperature inside the ladle 4 may be continuously measured continuously. Further, the same temperature measuring unit as the ladle temperature measuring unit 6 </ b> A may be disposed in the melting and holding furnace 1 and the electromagnetic stirring device 7.

  The die casting machine 11 also includes a fixed mold 15 provided on the fixed die plate 16 and a movable mold 14 provided on the movable die plate 13, and the movable mold 14 and the movable die plate 13 drive means (not shown). Is moved to a position where it abuts against the abutment surface of the fixed mold 15, and the fixed mold 15 and the movable mold 14 are combined to form a shape corresponding to the shape in both the molds 14, 15 by a semi-solid slurry. A predetermined molded product is molded. At this time, the semi-solid slurry is formed in advance in the cup 5, and this semi-solid slurry is introduced from an unillustrated inlet of the injection sleeve 12 penetrating into the fixed mold 15 from the fixed die plate 16 side. After that, it is pushed out by a plunger that slides back and forth in the injection sleeve 12 and is supplied into both molds 14 and 15. Then, as the plunger slides in the injection sleeve 12, the semi-solid slurry is mold-clamped into a form corresponding to the internal shape of each of the fixed mold 15 and the movable mold 14 that are abutted with each other. is there.

  The injection sleeve 12 is formed in a tubular shape with a relatively low hardness material such as ceramic, casting, copper alloy, etc., and has a length corresponding to a portion that does not need to be pushed into the semi-solid slurry until it hits the movable mold 14. The operation stroke of the plunger can be shortened by making it as short as possible, that is, the length corresponding to the length to be pushed in. Further, a projecting pushing mold for mold clamping is projected on the abutting surface side of the movable mold 14, and when the molds 14 and 15 are abutted with each other, this projection A shaped pressing mold is fitted to the distal end side of the injection sleeve 12 on the abutting surface of the fixed mold 15.

  The moving mechanism 8 described above uses the loading / unloading robot 21 provided on the distal end side of the injection sleeve 12 on the abutting surface side of the fixed mold 15 that abuts the movable mold 14. That is, the loading / unloading robot 21 is provided with a chuck portion 23 composed of a pair of clamping pieces that are opened and closed by an air cylinder at the tip of a robot arm 22. At the time of casting, the cup 5 containing the semi-solid slurry is gripped by the chuck portion 23, the semi-solid slurry in the cup 5 is put into the injection sleeve 12, and temporarily retracted during molding. After the molding, when the movable mold 14 is pulled away from the fixed mold 15, the tip of the robot arm 22 enters the take-out position of a predetermined cast finished product molded by the semi-solid slurry, and chucks from the inside of the pressing mold. It is gripped by the section 23 and transferred to the product conveyor 51.

  As a specific example of the moving mechanism unit 8, a loading / unloading robot 21 provided with a robot arm 22 having a multi-axis joint structure is used. The loading / unloading robot has a multi-axis joint structure, and a plurality of arms are sequentially connected to a base installed on the installation surface, and each arm is bent and rotated by the axial joint of the connecting portion. By performing these operations, the wrist can be controlled to move three-dimensionally within a predetermined range.

  Next, an example of a processing procedure by the automatic water heater 3, the melt temperature adjusting mechanism 6 in the ladle, the moving mechanism unit 8 and the like according to the embodiment configured as described above will be described in detail based on the flowchart shown in FIG. . In the melting and holding furnace 1, for example, a molten metal S having a melting temperature of, for example, 640 ° C. such as an aluminum alloy is held. In addition, a heat-resistant cup 5 having, for example, a half-elliptical shell shape is accommodated and held inside the accommodating portion 7 a of the electromagnetic stirring device 7.

  First, in step S1, the ladle driving unit 3A of the automatic hot water supply device 3 is operated to pump up the molten metal S of the melting and holding furnace 1 by the ladle 4. At this time, the molten metal S is weighed by a command from the hot water temperature measurement control device 6B, for example, about 40 g, and in some cases, an arbitrarily large amount of the molten metal S is pumped up by the ladle 4.

  In step S2, the ladle driving unit 3A is operated to move the ladle 4 to the vicinity of the accommodating unit 7a of the electromagnetic stirring device 7, where the temperature of the molten metal S in the ladle 4 is measured by the ladle temperature measuring unit 6A. Is sent to the hot water supply temperature measurement control device 6B.

  In step S3, it is determined whether or not the temperature of the molten metal S in the ladle 4 is lower than a predetermined temperature, for example, a temperature of 640 ° C. in the case of an aluminum alloy. When the temperature is lower than 640 ° C. (S3: YES), the process proceeds to step S4. When the temperature is higher than 640 ° C. (S3: NO), the process proceeds to step S5.

  In step S4, the molten metal S in the ladle 4 is returned to the melting and holding furnace 1 to raise the furnace temperature. Then, the ladle driving unit 3A is operated to move the ladle 4 again to the vicinity of the accommodating portion 7a of the electromagnetic stirring device 7, where the temperature of the molten metal S in the ladle 4 is measured by the ladle temperature measuring unit 6A. The operation in step S4 is repeated at least three times. That is, when it is measured that the temperature of the molten metal S is low about three times, a signal is sent from the hot water supply temperature measurement control device 6B to the temperature adjusting unit 2 of the melting and holding furnace 1 to energize the heater H and raise the furnace temperature. . Thereafter, the process proceeds to step S6.

  In step S5, when it is determined in step S3 that the temperature of the molten metal S in the ladle 4 is higher than the temperature of 640 ° C. (S3: NO), the ladle of the automatic water heater 3 is instructed by a command from the hot water temperature measurement control device 6B. The driving unit 3A is operated, and the ladle 4 is placed on a heat release stand-by in the air until the temperature of the molten metal S decreases to a temperature of 640 ° C.

  In step S6, it is determined whether or not the temperature of the molten metal S in the ladle 4 has decreased to a predetermined temperature, for example, a temperature of 640 ° C. in the case of an aluminum alloy. When this determination is not satisfied (S6: NO), the process returns to step S5 and the ladle 4 continues to wait for heat radiation in the air. When this determination is satisfied (S6: YES), the process proceeds to the next step S7.

  In step S7, the ladle driving portion 3A is operated to move the ladle 4 to the position of the accommodating portion 7a of the electromagnetic stirring device 7, and the molten metal S in the ladle 4 is supplied to the cup 5 in the accommodating portion 7a.

  In step S8, the molten metal S is formed into a semi-solid slurry by the electromagnetic stirring device 7. As described above, the electromagnetic stirring operation causes the molten metal S to generate an axial motion, and the rotating magnetic field generating coil provided along the outer peripheral surface of the container that accommodates the cup 5 to generate the rotational motion of the molten metal S. This is executed in combination with an axially moving magnetic field generating coil provided along the axial direction of the outer peripheral surface of the container that accommodates the cup 5 for the purpose. Thereafter, this flow ends.

DESCRIPTION OF SYMBOLS S ... Molten metal H ... Heater 1 ... Melt holding furnace 2 ... Temperature adjustment part 3 ... Automatic hot water supply device 3A ... Ladle drive part 4 ... Ladle 5 ... Cup 6 ... Molten metal temperature adjustment mechanism 6A ... Ladle temperature measurement part 6B ... Hot water supply temperature Measurement control device 7 ... Electromagnetic stirring device 7a ... accommodating portion 8 ... moving mechanism portion 11 ... die casting machine 12 ... injecting sleeve 13 ... movable die plate 14 ... movable die 15 ... fixed die 16 ... fixed die plate 21 ... loading / extracting Robot 22 ... Robot arm 23 ... Chuck part 41 ... Cup preparation device 51 ... Product conveyor

Claims (1)

An automatic hot water supply device that pumps molten metal from the melting holding furnace with a ladle and a cup to which the molten metal pumped up by the ladle of the automatic hot water supply device is accommodated between the magnetic field generating coils. Automatic equipped with an electromagnetic stirrer that forms a solidified semi-solid slurry and a moving mechanism that puts a cup containing the semi-solid slurry into an injection sleeve that is inserted into the fixed mold side of the die casting machine. A melt temperature adjustment mechanism in the ladle of the casting apparatus, a ladle temperature measurement unit for measuring the melt temperature in the ladle immediately before being fed into the cup, and a temperature adjustment unit for adjusting the furnace temperature of the melting holding furnace, Based on the measurement information of the ladle temperature measuring unit, the ladle standby or return operation by the automatic water heater and the inside of the melting holding furnace after returning the molten metal in the ladle Made by have a hot water supply temperature measurement control apparatus capable of temperature control by communication to the temperature adjustment unit, the ladle temperature measuring unit accommodating portion formed in the electromagnetic stirring apparatus to removably accommodate holding the cup When the ladle that contains the pumped molten metal is moved to the vicinity of the housing part, it is composed of a thermocouple thermometer and thermistor suspended from the side of the hot water temperature measurement control device installed in the vicinity of the molten metal. A mechanism for adjusting a molten metal temperature in a ladle of an automatic casting apparatus, wherein the molten metal temperature is inserted into the ladle.

Images