JPH05318082A - Method for feeding and casting molten metal - Google Patents

Abstract

PURPOSE:To prevent the burn of a molten metal in a holding furnace by rapidly heating transporting pipes from the outer periphery to heat the molten metal up to a correct casting temp. CONSTITUTION:The melt M of the metal in the holding furnace 24 is delivered by an oil feed pump 25 and is supplied through the transporting pipes 20, 22 into a casting device. The molten metal is thereafter cast into the cavity 8 of molds 1 by the operation of the casting device. The temp. of the molten metal M in the holding furnace 24 is kept lower than the correct casting temp. suitable for casting and the transporting pipes 20, 22 are heated by a rapid heater 21 from the outer periphery. The temp. of the molten metal to be cast into the casting device is increased up to the correct casting temp. in such a manner. As a result, the good casting is executable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal hot water pouring method, and more particularly to a molten metal hot water pouring method which is improved so as to be suitable for magnesium alloy tie casting.

[0002]

2. Description of the Related Art Conventionally, a casting which is communicated with a casting sleeve through which a casting sleeve is engaged and a runner portion which is an upwardly directed hot water feeding passage. In order to perform casting with a die casting apparatus equipped with a die apparatus having a cavity of (1) and a hot water supply apparatus for supplying hot water into the casting sleeve, the molten metal is put into the casting sleeve and the casting sleeve is placed in the die. It is arranged to engage with the casting port at the bottom and then raise the casting plunger to send the molten metal in the casting sleeve into the cavity for casting.

As a method of pouring the molten metal into the casting sleeve, there is a method of separating the casting sleeve from the mold and pouring it with a ladle. In order to make it easier to pour the molten metal in the ladle, the casting sleeve may be tilted (for example
No. 1414 gazette (FIG. 3), the casting sleeve is retracted from the lower side of the mold with the vertical posture (FIG. 4 of the same gazette). In Fig. 2 of the same issue, the lower mold is lowered while the casting sleeve is attached to the lower mold, and the molten metal is poured into the casting sleeve from above the lower mold through the hot water supply passage through the hot water supply passage. It is shown.

In the method in which the casting sleeve is separated from the mold and the molten metal is poured by the ladle, the time from pouring the molten metal to the casting sleeve until actually injecting it into the cavity becomes long. In addition, foreign substances are easily mixed in the molten metal. Further, when the casting sleeve is tilted, the molten metal cannot be filled to the upper edge of the casting sleeve, so that the casting sleeve needs to be lengthened accordingly. Even in the method of pouring the molten metal from above the lower mold while the lower mold and the casting sleeve are attached to each other, it is necessary to wait only while the upper mold and the lower mold are clamped, and the injection time is long. Become. Further, there is a problem that the spilled molten metal is easily splashed on the upper surface of the lower mold.

Further, in any of the above methods, the molten metal is exposed to the atmosphere when it is transferred to the pouring sleeve or until the pouring sleeve is engaged with the pouring port. For this reason, the molten metal is easily oxidized and is not suitable for casting easily oxidizable metals (eg magnesium, aluminum and its alloys), and there is a possibility that casting defects may occur due to the inclusion of oxides.

Therefore, the inventor of the present application, as one of means for solving this problem, for example, as shown in FIG. 2 (filed as Japanese Patent Application No. 3-36089), casts on a mating surface. A mold 3 having a movable mold 5 in which a cavity 8 is formed and a fixed mold 3, and with which a casting sleeve 9 is engaged.
5 Mold device 1 communicated with a casting cavity 8 via a lower casting port 6 and a runner portion 7 which is an upwardly extending hot water feeding passage, and a molten metal storage tank for supplying hot water into a casting sleeve 9. In a mold casting device provided with a hot water supply device 23 in which a pump device 25 is arranged in 24, the mold casting device is provided in the fixed mold 3 and is opened on the inner wall surface of the casting port 6 or the runner portion 7. The horizontal hot water supply passage 13, the lower surface of the rear side of the hot water supply passage 13 that communicates with the hot water supply device 23, and the molten metal heating heater 35 provided in the conduit 22.
And a valve seat 15 provided in a tapered shape in the hot water supply passage 13 in the vicinity of the spout 6 or the runner portion 7 and expanding toward the movable mold 5, and held by the movable mold 5. A mold casting apparatus having a valve body 16 of an on-off valve 14 for opening and closing a hot water supply passage that is moved forward and backward with respect to the valve seat 15 by an opening and closing cylinder 17 has been developed.

In FIG. 2, 2 is a fixed platen, and 4 is a movable platen which moves in the left-right direction in the figure by a toggle mechanism (not shown). Further, 40 is a feeder pin, 41 is a feeder cylinder, 43 is a product extruding pin device, 44 is a die degassing device, and 45 is a degassing groove provided on the separating surfaces of the dies 3 and 5. Reference numeral 10 is a casting device, 11 is a casting plunger that slides vertically in the casting sleeve 9, and the casting plunger 11 is connected via a rod 12 to a casting cylinder (not shown).

The hot water supply device 23 includes a molten metal storage tank 24 which is a holding furnace for the molten metal, and a pump device 25 which is a hot water supply pump for pumping the molten metal M into the storage tank 24. The pump device 25 includes a cylinder barrel 27 in which a piston 26 is vertically movably inserted, and a cylinder 28 for vertically moving the piston 26. The inside of the cylinder barrel 27 is provided with a passage 29 and a suction port 30. And communicates with the storage tank 24. The valve rod 31 so as to open and close the suction port 30
Is provided, and the valve rod 31 is vertically moved by the valve cylinder 32. The molten metal in the cylinder barrel 27 can be sent to the conduit 22 which is a transportation pipe through the passage 33 and the check valve 34.

In the fixed mold 3, a rod 36 is slidably provided on the fixed platen 2 side of the horizontal hot water supply passage 13. Reference numeral 37 is a cylinder fixed to a part of the fixed platen 2. By the operation of the cylinder 37, the rod 36
Can be taken in and out of the hot water supply passage 13 and retracted. In addition, a passage 38 as shown in FIG. 2 is provided in the rod 36, and the rear of the passage 38 is connected to a not-shown inert gas supply source such as oxygen via a connecting tool 39. The front of the passage 38 is opened to the outer peripheral surface near the tip of the rod 36.
When the water is advanced to the hot water supply passage 13 part, the hot water supply passage 13 is tapered from the opening of the passage 38 toward the end.
Oxygen can be supplied into the cavity 8 through a narrow passage between the inner peripheral surface and the inner peripheral surface. A passage 46 communicating with the outside air is provided on the sliding surface of the rod 36 behind the hot water supply passage 13 of the fixed mold 3, and when the rod 36 retracts, the hot water supply passage 13 passes through the passage 46 to the outside air. It is supposed to be understood.

In this mold casting apparatus, the opening / closing valve 14 is opened and the pump device 25 is operated while the casting sleeve 9 is attached to the casting port 6 of the clamped molds 3, 5. Then, the molten metal in the storage tank 24 is fed from the water heater 23 to the mold 3,
Hot water is supplied to the pouring port 6 or the runner portion 7 inside 5. This molten metal is stored in the casting sleeve 9. After supplying the required amount of molten metal, the on-off valve 14 is closed and the injection plunger 11 is immediately raised to inject the molten metal into the cavity 8. In this case, the temperature of the molten metal in the storage tank 24 and the temperature of the molten metal injected into the cavity 8 differ depending on the material, but in the case of the magnesium alloy, they are kept at, for example, 670 to 700 ° C.

[0011]

In this case, since the temperature of the molten metal in the molten metal storage tank 24 is kept at the same temperature as the casting temperature in the cavity 8 or higher than that temperature, the molten metal is In the case of an alloy, the molten metal may be in contact with air and burn in the storage tank 24, which is extremely dangerous. In order to prevent the molten metal in the storage tank 24 from reacting with oxygen in the air and burning, the storage tank 24 is closed and a non-combustible gas such as SF6 is supplied into the storage tank 24 to convert the molten metal into a non-combustible gas. I tried to hold and supply it in the atmosphere, but the sealed part of the storage tank 24 could not be completely sealed and the outside air was inevitably closed.
There was an air leak that entered, and the magnesium alloy burned, which was dangerous.

[0012]

In the present invention, in order to solve the above-mentioned problems, the molten metal of the metal in the holding furnace is delivered by a hot water supply pump and is supplied into the pouring device through the transport pipe, and then the casting is performed. When casting into the mold cavity by operating the equipment, the temperature of the molten metal in the holding furnace is kept lower than the proper casting temperature suitable for casting, and the transport pipe is heated from the outer periphery by a rapid heating device. The temperature supplied to the pouring device was raised to the proper pouring temperature.

[0013]

[Function] The temperature of the molten metal in the holding furnace is set lower than the proper pouring temperature suitable for casting, that is, the temperature is set to a temperature at which the molten metal has sufficient fluidity but does not burn immediately before the oxidation becomes severe. Keep the temperature of the molten metal rapidly in the transportation pipe on the way from the pump device to the casting sleeve. When the molten metal enters the casting sleeve, it seems that the molten metal has an appropriate casting temperature suitable for casting. Then, under this temperature condition, it is cast into the cavity of the mold.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of an apparatus for carrying out the present invention. Note that FIG. 1 is almost the same as that shown in FIG. As shown in FIG. 1, the mold device 1 includes a fixed mold 3 attached to a fixed plate and a movable plate which is moved forward and backward with respect to the fixed mold 3 by a toggle mechanism (not shown) in the left-right direction of the drawing. It is mainly configured by the attached movable mold 5. A casting port 6 is provided on the bottom surface of the mold including the fixed mold 3 and the movable mold 5, and the molten metal can be supplied to the cavity 8 via the runner portion 7 serving as the molten metal feeding passage.
At the upper end of the mating surface of the fixed mold 3 and the movable mold 5, a conventionally known mold degassing device corresponding to 44 in FIG. 2 for discharging air and gas from the cavity 8 and the casting sleeve 9 is provided. It is installed. The upper end of the casting sleeve 9 can be engaged with the casting port 6. The casting sleeve 9 is provided at the upper end portion of the casting device as shown in FIG. 2, and the casting plunger is slidably arranged in the casting sleeve 9. The casting plunger is vertically moved by the casting cylinder. After the casting sleeve 9 is slightly lowered from the state shown in FIG. 1 and separated from the molds 2 and 3, and is rocked laterally or moved horizontally to move the opening to a position away from the mold position. The inside of the casting sleeve 9 can be cleaned by spraying or a lubricant can be applied.

From the opening of the inner peripheral wall surface of the runner portion 7 to the casting port 6
The hot water supply passage 13 is provided in the fixed mold 3 so that the pouring port 6 and the inside of the transport pipe 20 that is in contact with the fixed mold 3 from the outside so as to supply the molten metal into the fixed mold 3 are slightly inclined. It is communicated through. The inner volumes of the hot water supply passage 13 and the transport pipe 20 are set to have a passage volume corresponding to the amount of molten metal for one shot. Then, the rapid heating, transporting, and holding of the molten metal by the rapid heating device 21 can be performed more effectively. An on-off valve 14 is provided in a portion of the hot water supply passage 13 facing the runner portion 7. The opening / closing valve 14 is held by a taper-shaped valve seat 15 that expands toward the movable mold 5 and is movable back and forth in the movable mold 5.
A valve body 16 that can be seated on the valve seat 15 is provided. A piston rod 18 of an opening / closing cylinder (valve body driving device) 17 fixed to a part of the movable mold 5 is connected to the valve body 16 by screwing. The open / close cylinder 17
A solenoid or the like may be used instead of. In FIG. 1, the solid line of the valve body 16 shows the valve closed state, and the two-dot chain line of the valve body 16 shows the valve open state.

The hot water supply passage 13 and the transport pipe 20 also serve as a molten metal reservoir. The inner surface of the transport pipe 20 in contact with the molten metal is an inner liner made of ceramic or heat-resistant metal (for example, SKD61), and an induction heating coil (induction heater) 21 which is a rapid heating device is provided on the outer peripheral side of the inner liner. There is. A vertical transport pipe 20a is attached to the rear lower surface of the transport pipe 20. 20b is a check valve. An inner liner made of ceramic or heat-resistant metal or an induction heating coil may be used around the hot water supply passage 13 in the fixed mold 3.

A horizontal transport pipe 2 is provided following a transport pipe 20 inclined so that hot water can be supplied to the hot water supply passage 13.
A hot water supply device 23 is installed via the 2. This hot water supply device 23 includes a holding furnace 24 which is also a tank for holding molten metal and a holding furnace 2
A hot water supply pump 25 is provided for pumping the molten metal in 4. The hot water supply pump 25 includes a cylinder barrel 27 in which a piston 26 is inserted, and a cylinder 28 for vertically moving the piston 26.
The inside is communicated with the holding furnace 24 via a passage 29 and a suction port 30. A valve rod 31 is provided to open and close the suction port 30, and the valve rod 31 is moved up and down by a valve cylinder 32. The molten metal in the barrel 27 can be sent to the transport pipe 22 via a passage 33 and a check valve 34. Reference numeral 35 is a heater provided on the outer circumference of the transport pipe 22.

The molten metal in the holding furnace 24 is kept at a temperature lower than a relatively high appropriate casting temperature suitable for casting the molten metal from the casting sleeve 9 into the cavity 8. For example, in the case of magnesium alloy AZ91, since the proper casting temperature is about 670 ° C., the temperature of the molten metal in the holding furnace 24 is kept at about 600 ° C. Further, in the case of AM60, since the proper casting temperature is about 700 ° C, the temperature of the molten metal in the holding furnace 24 is kept at about 620 ° C. Thus, in the case of magnesium alloy, for example, a temperature lower than the proper casting temperature suitable for casting at 670 to 700 ° C., for example, 600 to
The temperature of the molten metal M in the holding furnace 24 is kept at 620 ° C.
At this temperature, the fluidity of the molten metal M is kept sufficiently so that it will not be used for transportation. However, even if the molten metal is in contact with air, the temperature immediately before the oxidation becomes violent, that is, the molten metal does not burn. Keep the temperature of the state. In addition, when the molten metal having a temperature lower than the proper casting temperature in the holding furnace 24 is put into the casting sleeve 9 to be cast at the proper casting temperature, the molten metal is transferred to the transport pipe. When passing through the inside of the transport pipe 20, the temperature of the molten metal is instantly raised by the action of the rapid heating device 21 such as an induction heater provided on the outer circumference of the transport pipe 20. The holding furnace 24 is hermetically sealed, and a non-combustible gas such as SF6 is put into the holding furnace 24 and sealed. In this way, even if some air leaks into the holding furnace 24 without being completely sealed, the molten metal will not burn due to the low temperature.

In the die casting machine thus constructed, when the valve rod 31 is raised and the piston 26 is raised in this state, the molten metal M in the storage tank 24 is transferred to the cylinder barrel 27.
Is sucked in. At this time, the passage 33, the transport pipes 22, 2
Since there are check valves 34 and 20b in the 0th section, the transport pipe 2
The molten metal M in Nos. 2 and 20 does not flow backward and is sucked into the cylinder barrel 27. Next, with the valve body 16 retracted to a predetermined position, the mold is clamped as shown in FIG. 1, and the casting sleeve 9 is docked on the lower surface of the molds 3, 5. It should be noted that it is preferable to introduce an inert gas such as nitrogen gas into the cavity 8 and expel the air in the cavity 8 and the casting sleeve 9 to fill it with the inert gas.

Next, the suction port 30 is closed by the valve rod 31, and as shown by the chain double-dashed line in FIG. Cylinder barrel 27
The molten metal M in the passage 33, the check valve 34, the transport pipe 2
2, it is poured into the casting sleeve 9 through the check valve 20b, the transport pipe 20, the hot water supply passage 13, the runner portion 7 and the casting port 6. The casting plunger 11 is raised to the upper limit in advance and gradually lowered as the molten metal M is poured. It is preferable in preventing. At this time, the inside of the casting sleeve 9 is filled with the inert gas, but as the molten metal drops into the casting sleeve 9 and is supplied, the inert gas inside the casting sleeve 9 is kept in the upper cavity. It is driven in eight directions and escapes from the open mold degassing device 44. In addition, hot water supply pump 2
When 5 is stopped, a part of the melt M in the hot water supply passage 13 whose inner surface is slightly tapered remains as it is.
Then, the next pouring can be performed efficiently in a shorter time.
However, the molten metal M passing through the hot water supply passage 13 and the transport pipe 22 is rapidly heated by the rapid heating device 21 and heated to a casting temperature suitable for casting.

After a sufficient amount of molten metal M is stored in the casting sleeve 9, the hot water supply pump 25 is stopped. In addition,
The molten metal in the hot water supply passage 13 and the transport pipe 20 remains as it is. Next, as shown by the solid line in FIG. 1, the valve element 16 is seated on the valve seal 15 to close the on-off valve 14, the casting plunger 11 is raised, and the molten metal M is cast into the cavity 8. At this time, the cavity 8 is filled with the inert gas, but when the molten metal M is cast into the cavity 8, the inert gas in the cavity 8 is released into the atmosphere via the gas vent passage and the die degassing device. Is discharged to. Of course, when the molten metal reaches the mold degassing device, the valve of the mold degassing device is closed by the inertial force of the melt or the electric command, and the molten metal enters or leaves the mold degassing device. There is no. Since the on-off valve 14 is provided in this embodiment, the molten metal M is reliably prevented from flowing backward toward the hot water supply passage 13 and the storage tank 24 due to the casting pressure.

At the time of casting, a feeder pin (not shown) is moved forward with the molten metal M substantially filled in the cavity 8 to perform a feeder operation. When the injection finishes and the molten metal in the cavity 8 solidifies and cools a predetermined time, the mold is opened. After that, after the product is taken out, the mold is clamped again, and the molten metal is supplied into the casting sleeve 9 by the same procedure as described above, and casting is performed.

Since the molten metal in the storage tank 24 is supplied into the casting sleeve 9 without being exposed to the atmosphere at all, even a molten metal such as aluminum or magnesium which is easily oxidized can be cast without causing any oxidation. .. Therefore, casting of easily oxidizable metal can be performed without any problems, and casting defects due to oxides can be reliably prevented.
It is possible to obtain extremely high quality cast products. In this embodiment, a cooling mechanism such as water cooling can be incorporated in the valve body 16. Thereby, the valve body 16 can be protected from high heat.

In the above-mentioned embodiment, the horizontal die-clamping die apparatus is shown in which the movable die 5 is clamped from the lateral direction to the fixed die 3 and is cast from below. , After the molten metal in the cavity 8 is solidified, the movable mold 5 is fixed to the fixed mold 3.
When the solidified product is removed from the casting product, the biscuit portion on the casting port 6 side of the on-off valve 14 can also be taken out together with the casting product. As is clear from the figure, since the casting sleeve 9 of this embodiment is in the vertical posture connected to the casting port 6 during casting, a large amount of the molten metal M can be poured into the casting sleeve 9 and the casting can be performed. The length of the sleeve 9 is also short and sufficient. It is also possible to clean the inside of the casting sleeve 9 by slightly lowering the casting sleeve 9 apart from the molds 3 and 5 and tilting it around the lower part of the casting device 10 except during casting. In the present invention, the mold may be a vertical mold clamping mold in which the movable mold is moved back and forth in the vertical direction.

[0025]

As described above, in the die casting method of the present invention, the molten metal in the holding furnace is fed by the hot water supply pump and supplied into the casting device through the transport pipe, and then the casting device is operated. When casting into the mold cavity by means of, the temperature of the molten metal in the holding furnace is kept lower than the proper casting temperature, and the transport pipe is heated from the outer circumference by a rapid heating device and supplied into the casting device. Since the temperature was raised to the proper pouring temperature, even when pouring a molten metal that burns easily or explodes in contact with air, the molten metal does not burn in the holding furnace. It is extremely safe. Of course, since the molten metal is rapidly raised to the proper pouring temperature by the action of the rapid heating device and is put into the pouring device for pouring, good pouring can be performed.

Further, since the molten metal in the hot water supply pump of the holding furnace passes through the transport pipe and the molten metal in the hot water supply device of the casting device is supplied to the transport pipe and the casting sleeve, the molten metal may not be spilled during the hot water supply. Absent. Furthermore, since the molten metal does not come into contact with the atmosphere during pouring, magnesium, such as magnesium, is extremely oxidizable, and even if it is easily exposed to the atmosphere and explodes, it can be reliably and easily cast. Can also be prevented. By using the non-porous die casting method in which the casting is performed in an inert gas atmosphere, it is possible to easily and easily obtain a good quality cast product with no cavities. In addition, the pouring time is extremely short and the casting cycle can be shortened, and the temperature of the molten metal to be cast is sufficiently high,
This also makes it possible to obtain a good quality cast product.

According to the present invention, the transport pipe attached to the fixed mold has a good sealing property, and the leak of the molten metal from the hot water supply passage is surely prevented. In the present invention, the casting sleeve can always be in a vertical posture, and a large amount of molten metal can be poured into the casting sleeve to shorten the length of the casting sleeve. If a check valve is provided at the transport pipe connection part of the hot water supply device, the reverse flow of the molten metal can be reliably prevented. Since the molten metal remaining in the conduit is heated by the heater provided in the conduit and maintained at the required temperature, it can be used as it is for the next pouring.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing one embodiment of an apparatus for carrying out the method of the present invention.

FIG. 2 is a longitudinal sectional view showing an embodiment of a conventional device similar to the device for carrying out the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold device 3 Fixed mold 5 Movable mold 6 Casting port 7 Runner part (hot water supply passage) 8 Cavity 9 Casting sleeve 13 Hot water supply passage 14 Open / close valve 15 Valve seat 16 Valve body 17 Open / close cylinder 20, 22 Transport pipe 21 rapid heating device 23 hot water supply device 24 holding furnace (storage tank) 25 hot water supply pump 26 piston 30 suction port 34, 20b check valve 35 heater 44 mold degassing device

Claims (1)

[Claims] 1. When casting a molten metal of a metal in a holding furnace by a hot water supply pump and supplying it into a casting device through a transport pipe, and then casting the molten metal into a mold cavity by operating the casting device,
The temperature of the molten metal in the holding furnace is set lower than the proper pouring temperature suitable for pouring, and the temperature supplied to the pouring device by heating the transport pipe from the outer periphery with a rapid heating device is the proper pouring temperature. The method of pouring molten metal hot water to a high temperature.