JP2005095921A - Casting method and casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a uniform quality and uniform cast product by pouring molten metal into a metallic mold with high accurate quantitative regulated pressure and regulated temperature. <P>SOLUTION: In a casting method by feeding the molten metal into the mold through a feeding device inserted into a holding furnace, when the molten metal is force-fed by force-feeding inert gas into the inside upper part of a feeding vessel in the feeding device, the molten metal surface at the starting time of force-feeding is held to the constant and the molten metal is fed while using the molten metal pressure with the pre-set pressure pattern. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a casting method and a casting apparatus aiming to perform uniform casting by keeping the temperature of a molten metal fed into a mold constant and changing a molten metal feeding pressure along a predetermined pattern.

  Conventionally, as shown in FIG. 7, the constant-quantity water feeding apparatus used has installed a holding furnace outside the melting furnace, and pressurized all the hot water surfaces of the holding furnace to feed hot water.

  Moreover, the apparatus which provided the tap which can be opened and closed to a hot water storage body and a constant temperature furnace body was also disclosed.

Furthermore, an apparatus of a type in which the molten metal flows from the holding furnace to the hot water tank has been disclosed.
JP-A-11-33706 JP 11-123531 A JP2000-210765A

  A conventionally used low-pressure casting method is mainly a method in which the upper surface of the molten metal in the closed furnace is pressurized and the molten metal is pressed into the mold.

  The closed furnace as described above has the following problems.

  (1) Since the molten metal level in the furnace changes due to casting, the calculated value of the molten metal surface position is entered and corrected to make the amount of casting accurate, but the calculated value is the same as the actual molten metal level. Since there is an error, the accuracy cannot be further improved.

  (2) Since it is a closed furnace, hot water cannot be distributed during casting.

  (3) Because of the closed furnace, the molten metal cannot be processed during casting.

  (4) Since the furnace needs to be sealed, it must be structurally strong, which makes it difficult to remove or clean the furnace lid.

  (5) Since the amount of other operations increases, it becomes difficult to obtain high accuracy in the casting amount. For example, conventionally, the entire liquid level 20a of the holding furnace 2 has been pressurized (FIG. 7).

  The present invention solves the above-mentioned conventional problems by putting a hot water supply apparatus into a holding furnace where molten metal is separated from a melting furnace and installing a mold above (directly above) the hot water supply apparatus.

  That is, the invention of the method is a method of feeding molten metal to a mold through a feeding device that has been put into a holding furnace, injecting an inert gas into the upper part inside the feeding tank of the feeding device, This is a casting method characterized in that when the molten metal is pressed into the mold, the molten metal pressure is kept constant and the molten metal pressure is fed in a predetermined pressurization pattern. The pressure is controlled, and the molten metal is distributed to the holding furnace during the pressure casting, and the molten metal in the furnace is treated.

  Further, the invention of the apparatus is the pressurization in which a feeding device is placed in a holding furnace, a partition wall for providing a constant hot water surface is provided in the feeding tank of the feeding device, and partitioned by the partition wall. The casting apparatus is characterized in that the feeding cylinder into the mold is inserted and installed in the chamber, the melt inflow means is provided on one side of the pressurizing chamber, and the pressurizing means is installed in the upper part. The cylinder is provided with heating means.

  Further, the inflow means is characterized in that the inlet tank is connected to a suction tank communicating with the holding furnace, and a valve means is interposed in the inlet section of the inlet tank or the inlet tank. The stop means is detachably installed in the suction hole of the suction tank, and the valve means provides a hot water passage to the partition wall of the suction tank or the inlet tank. It is characterized in that a float valve is interposed.

  In the present invention, the hot water supply apparatus to be charged into the holding furnace is an apparatus in which the suction tank, the intermediate tank and the input tank are integrally connected, or an apparatus in which the suction tank and the input tank are integrally connected, or Although it may be only an entrance tank, it is easier to control when the suction tank and the intermediate tank or the intermediate tank are set as the input tank, and more accurate hot water can be supplied.

  The valve device according to the present invention prevents the backflow of the molten metal, and the molten metal once sucked into the hot water supply device does not return to the holding furnace, which is a preferable means in terms of efficiency.

  According to the said apparatus, there exists an advantage from which the temperature control of a molten metal is easy and the regulation of the amount of hot water supply becomes high precision. In addition, the length of the hot water canister as it reaches from the feeding tank to the mold can be shortened as much as possible, and temperature control is easy by providing a heating layer (for example, an embedded heating wire) in the exposed portion of the hot water canister. It becomes.

  According to this invention, it is possible to feed a molten metal at a predetermined temperature from a feeding tank 1 of a feeding apparatus that has been put into a holding furnace into a mold according to a predetermined pattern at a necessary pressure and at a necessary pressure. As a result, uniform products can be automatically and low-pressure casted.

  In particular, since the molten metal can be smoothly transferred and continuously fed by patterning the feeding pressure, it is possible to homogenize the product by controlling the feeding speed and improving the casting accuracy during casting.

  In this invention, a hot water supply apparatus is placed and installed in a holding furnace into which molten metal separated from a melting furnace is placed, and a mold is placed on the upper part of the hot water supply apparatus, so that the molten metal in the holding furnace is low-pressure quantitative hot water supply. In the casting time zone, the pressure is changed to homogenize each part of the cast product, and the product is made uniform.

  This invention changes the hot water supply pressure according to the shape of the metal material and the shape of the product, the shape of the mold corresponding to the structure, and the structure, and aims to improve the casting efficiency based on homogenization during condensation. Is.

  In the present invention, a hot water supply apparatus is put into a holding furnace. In this hot water supply apparatus, a suction tank communicating with the holding furnace, an intermediate tank, and a feed tank are sequentially provided. Therefore, the molten metal is sucked into the suction tank, then pressurized and fed into the intermediate tank, and further pressurized and fed into the feeding tank.

  Further, an inert gas supply / discharge pipe is connected to each tank, a predetermined inert gas is supplied, and the molten metal in the tank is transferred to the next tank (or mold) by pressurizing the molten metal surface. Next, a new molten metal is sucked from the holding furnace by discharging the inert gas. The above operation is repeated to continue casting.

  In the above, if the suction tank is at atmospheric pressure, the hot water surface in the hot water supply device can be automatically supplied up to the hot water surface of the holding furnace. If the hot water level is kept equal to or higher than the required hot water level of the suction tank, the operation of the suction tank is simplified.

  Next, when shifting from the suction tank to the intermediate tank, the suction hole is closed, and an inert gas is pressurized and fed into the upper part of the suction tank. In this case, if the suction hole is not blocked, a part of the molten metal flowing to the intermediate tank flows backward from the suction hole into the holding furnace, and the inflow efficiency to the intermediate tank may be deteriorated.

  In this invention, in order to send the molten metal from the feeding tank to the mold, the inert gas is pressurized and fed to the upper part of the feeding tank. This gas feeding pressure is due to the solidification characteristics of the metal during casting. If the pressure is not the same and not according to a predetermined pressure change pattern, non-uniform solidification is likely to occur.

  Therefore, it is necessary to pressurize and feed based on a program that defines a predetermined pressure change. For example, it is necessary to set the feeding pressure to show a change as shown in FIG.

  An embodiment of the present invention will be described with reference to FIG. An appropriate quality molten metal is made in the melting furnace 1, and this is separated into the holding furnace 2.

  In the holding furnace 2, a suction tank 3, an intermediate tank 4, and an infeed tank 5 are sequentially integrated. A mold 7 is installed in the upper part of the feeding tank 5, the inside of the feeding tank 5 and the mold 7 are connected by a feeding cylinder 8, and a heater 9 is embedded in the upper outer wall of the feeding tank 8. Therefore, the temperature of the flowing molten metal can be adjusted.

  In the embodiment, when the stopper 12 of the suction hole 11 provided in the lower part of the suction tank 3 is pulled up to open the suction hole 11, the molten metal flows into the suction tank 3. For example, when the molten metal surface coincides with the molten metal surface of the holding furnace 2 (or reaches a predetermined molten metal surface), the stopper 12 is lowered to close the suction hole 11.

  Next, when the inert gas is pressurized and introduced into the suction tank 3 from the inert gas supply / discharge pipe 13, the molten metal in the suction tank 3 is pressurized and flows, and enters the intermediate tank 4. Next, after the molten metal is newly sucked into the suction tank 3, when the liquid level of the intermediate tank 4 is pressurized with an inert gas, the molten metal in the intermediate tank 4 is transferred to the feeding tank 5. Therefore, the molten metal in the suction tank 3 is moved again to the intermediate tank 4, and the molten metal in the holding furnace 2 is moved to the suction tank 3. As described above, if the molten metal is sequentially moved from the holding furnace 2 to the suction tank 3, the intermediate tank 4 and the feeding tank 5, and a certain amount of molten metal is intermittently pressed from the feeding tank 5 to the casting mold 7, the low pressure casting is continued. can do.

For example, aluminum product weighs 30kg is a melt temperature of 620 ° C. to 700 ° ^C., after flowing required amount destined to die by the pressure of ^{0.25kg / cm 2 ~0.8kg / cm 2} , 4 minutes Low pressure casting can be done in ~ 6 minutes.

  In the above, at the time of pressurizing and feeding into the intermediate tank 4 or the feeding tank 5, it is more preferable to install a valve means for preventing a backflow in the downstream passage.

  An embodiment of the apparatus of the present invention will be described with reference to FIGS. On the support stand 6 in the holding furnace 2, a molten metal feeding device 10 including a suction tank 3, an intermediate tank 4 and a feeding tank 5 is installed.

  The suction tank 3, the intermediate tank 4 and the inlet tank 5 are sealed by top walls 3a, 4a and 5a, respectively, and inert gas supply and discharge pipes 13, 14, and 15 are connected to the top walls. doing.

  In addition, a suction hole 11 communicating with the holding furnace 2 is formed in the bottom wall 3c of the suction tank 3, and a stopper 12 is fitted into the suction hole 11 so as to be freely opened and closed, and from the top walls 3a and 4a to the partition wall 3b. 4b is suspended, communication holes 3d and 4d are provided between the bottom walls 3c and 4c, and tank walls 34 and 45 are provided between the bottom walls 3c and 4c and between 4c and 5c, respectively. The tank wall 34 is a common wall for the suction tank 3 and the intermediate tank 4, and the tank wall 45 is a common wall for the intermediate tank 4 and the feeding tank 5.

  Next, the mold 7 is installed on the upper part of the infeed tank 5, the upper end of the infeed cylinder 8 is connected to the mold 7, and the lower part of the infeed cylinder 8 is inserted into the infeed tank 5, The lower end of the cylinder 8 is opened with a slight gap from the bottom wall 5c of the feeding tank 5.

  The operation of the embodiment will be described. The holding furnace 2 is appropriately fed with hot water from the melting furnace 1 and the molten metal surface is kept constant under atmospheric pressure. That is, if the molten metal in the holding furnace 2 is reduced, it is appropriately replenished and controlled so that there is no excess or deficiency.

  First, when the valve rod 12a of the stopcock 12 is pulled up as indicated by an arrow 16 and exhausted as indicated by arrows 17, 18, and 19 from the supply and discharge pipes 13, 14, and 15, respectively, each tank is decompressed. Therefore, the molten metal 20 in the holding furnace 2 enters each tank as indicated by arrows 21, 22, 23, 24, 25, and when the molten metal reaches the molten metal surface 20a, the valve rod 12a is returned as indicated by the arrow 26 and stopped. While closing the stopper 12, the exhaust from the supply / discharge pipes 13, 14, and 15 is stopped (becomes the hot water surface 20a in FIG. 2).

  Next, to supply hot water to the mold 7, if an inert gas (for example, nitrogen gas) is pressurized and fed from the water supply pipe 15 as indicated by arrow 27, the hot water surface 20 a is indicated by arrows 28 and 29. Since the pressure is lowered, the molten metal in the feeding tank 5 partitioned by the common wall 45 moves up the feeding cylinder 8 as indicated by arrows 30 and 31 and is fed into the mold 7. In this case, as shown in FIG. 6, for example, as shown in FIG. 6, it is always possible to start pressurization at a constant level, increase pressure successively, feed hot water in the same pressurization pattern, and cast.

  Next, after the suction hole 11 is closed with the stopper 12, if pressurized gas is fed from the supply / discharge pipe 13 of the suction tank 3 as indicated by arrow 32, the molten metal in the suction tank 3 is indicated by arrow 22, Like 23, 24, 25, it moves to the intermediate tank 4 and the inflow tank 5, and the intermediate tank 4 and the inflow tank 5 are filled again with the molten metal. In this case, even if the pressurization in the suction tank 3 is stopped, the molten metal once sent by the tank walls 34 and 45 does not flow backward. Therefore, the stopcock 12 is opened, the inside of the suction tank 3 is decompressed, and the molten metal in the holding furnace 2 is caused to flow as indicated by arrows 21 and 22 to prepare for the next hot water supply. In this way, intermittent hot water supply can be repeated, the molten metal can be sent to the mold 7, and low pressure casting can be continued.

  Another embodiment of the present invention will be described with reference to FIG. In the second embodiment, the molten metal feeding device 10 of the casting apparatus is connected to three types of the suction tank 3, the intermediate tank 4, and the feeding tank 5, but the embodiment of FIG. A tank 5 was used. Therefore, although the molten metal is not temporarily stored in the intermediate tank, the molten metal can be intermittently and quantitatively fed by the joint of the suction tank 3 and the feeding tank 5 without any trouble.

  In the above, the automatic valve 36 is provided in the common tank wall 35 of the suction tank 3 and the inflow tank 5, and the stopper 12 is plugged into the suction hole 11 provided in the bottom wall 3c (or the side wall) of the holding tank 2 of the suction tank 3. And connecting the supply / discharge pipes 13 and 15 to the suction tank 3 and the feed tank 5, respectively, can perform the same operation as in the second embodiment.

  The automatic valve 36 is configured by inserting a valve body 37 made of a ceramic ball inside the upper part of the communication tube 33. When the molten metal is sent from the suction tank 3 to the feeding tank 5 as indicated by an arrow 38, the automatic valve 36 pushes up the valve body 37 as indicated by an arrow 39, and from the groove 33a of the communication cylinder 33. The molten metal is fed as indicated by arrow 50.

  On the other hand, when the inert gas is injected into the inflow tank 5, the hot water surface flows backward from the groove 33a until the hot water surface reaches the upper surface of the common tank wall 35, but the hot water surface is the same as the lower wall 33b of the groove 33a. When it becomes high, the valve body 37 also descends and closes the upper part of the communication cylinder 33, so that the molten metal does not flow back, and the molten metal in the feeding tank 5 is sent to the mold 7 via the feeding cylinder 8 as indicated by arrows 51, 52. Can be sent in.

  As described above, when there is no molten metal in the feeding tank 5, the stopper 12 is lifted as shown by an arrow 49, the suction hole 11 is opened, and the molten metal in the holding furnace 2 is moved into the suction tank 3. Can flow in. In this case, when the hot water level of the holding furnace 2 is high, natural suction is performed, and when the hot water level of the holding furnace 2 does not reach the required height in the suction tank 3, the upper part of the suction tank 3 is decompressed and held. The molten metal in the furnace 2 is sucked.

  As described above, if the molten metal is sucked into the suction tank 3, the valve rod 12 a of the stopcock 12 is lowered to close the suction hole 11, and then the supply pipe 13 is not shown as an arrow 53. Activated gas is introduced, the inside of the suction tank 3 is pressurized, and the molten metal in the suction tank 3 is put into the feeding tank 5 as indicated by arrows 38 and 50, and the mold is passed through the feeding cylinder 8 by the same operation as described above. 7 can be fed (FIG. 4).

  Another embodiment of the present invention will be described with reference to FIG. In the third embodiment, the suction tank 3 and the feeding tank 5 are connected and used. However, in this embodiment, the feeding tank 5 is placed in the holding furnace 2 and is placed above the feeding tank 5. While installing the casting mold 7, the feeding cylinder 8 fixed to the casting mold 7 is inserted into the feeding tank 5, and the feeding tank 5 is sealed, and the supply / discharge pipe 15 is connected and opened to the top wall. A suction passage 40 communicating with the holding furnace 2 is provided at a lower part of the feeding tank 5, and a valve body 41 can be opened and closed in the suction passage 40 and an automatic valve 54 is installed.

  In the above, if the gas in the inflow tank 5 is exhausted from the supply / discharge pipe 15 as shown by arrow 44, the molten metal in the holding furnace 2 pushes up the valve body 41 as shown by arrows 42 and 43, and then enters Enter the tank 5 and reach the hot water surface 55. Therefore, if pressurized gas is fed from the supply / exhaust pipe 15 as indicated by arrow 46, the hot water surface in the feeding tank 5 is reduced as indicated by arrow 56, and as indicated by arrows 47 and 48. It is sent to the mold 7. When a necessary amount of molten metal is fed into the mold 7, the gas in the feeding tank 5 is discharged again and the molten metal in the holding furnace 2 is sucked into the feeding tank 5.

  In this way, the suction of the molten metal and the feeding into the mold 7 can be intermittently repeated to perform low pressure casting.

  However, since the required amount of molten metal can be sent at the required pressure, a uniform product can be mass-produced. A heating unit 57 is installed at the upper part of the feeding cylinder 8 of each feeding tank 5 to heat the upper part of the feeding cylinder 8 and adjust the molten metal temperature.

The block diagram of the Example of this invention. Sectional drawing which abbreviate | omitted a part of Example of the apparatus similarly. Explanatory drawing which similarly shows the movement of the molten metal of the Example of FIG. (A) Sectional drawing which abbreviate | omitted a part of other Example similarly, (b) Partial sectional drawing of the Example of an automatic valve similarly. Sectional drawing which abbreviate | omitted a part of other Example similarly. Explanatory drawing which similarly shows the relationship between a feeding device and a pressure. Similarly explanatory drawing of the conventional holding furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Holding furnace 3 Suction tank 4 Intermediate tank 5 Feeding tank 6 Support stand 7 Mold 8 Feeding cylinder 10 Molten metal feeding apparatus 11 Suction hole 12 Stopper 13, 14, 15 Feeding pipe 34, 45 Tank wall 36 54 Automatic valve

Claims (8)

  In the method of sending the molten metal to the mold through the feeding device put into the holding furnace, the inert gas is pressed into the upper part of the feeding tank of the feeding device, and the molten metal is pressed into the mold. In this case, the casting method is characterized in that the molten metal pressure is kept constant and the molten metal pressure is fed in a predetermined pressure pattern.   2. The casting method according to claim 1, wherein the temperature and pressure of the hot water supplied to the mold are controlled.   2. The casting method according to claim 1, wherein the molten metal is distributed to the holding furnace during the pressure casting, and the molten metal in the furnace is treated.   A feeding device is installed in the holding furnace, a partition wall is provided in the feeding tank of the feeding device to make a constant hot water surface, and the mold is fed into the pressure chamber partitioned by the partition wall. A casting apparatus in which an inlet cylinder is inserted and installed, a melt inflow means is provided on one side of the pressurizing chamber, and a pressurizing means is installed on the upper side.   The casting apparatus according to claim 4, wherein the feeding cylinder is provided with heating means.   5. A casting apparatus according to claim 4, wherein the inflow means is connected to a suction tank communicating with a holding furnace, and a valve means is interposed in the suction tank or the inflow part of the feed tank.   7. The casting apparatus according to claim 6, wherein the valve means is installed in a suction hole of the suction tank so that a stopper can be fitted and removed.   7. The casting apparatus according to claim 6, wherein the valve means is provided with a hot water passage in the partition wall of the suction tank or the inlet tank, and a float valve is interposed in the hot water passage.

Images