JPH03165961A - Method and apparatus for casting with pressurizing - Google Patents

Abstract

PURPOSE:To obtain the quality having high reliability and high accuracy by arranging a melting furnace or holding furnace and a mold in a pressure vessel, casting in this pressurized vessel and executing pressure control while linking with progress of solidification of a casting. CONSTITUTION:Inner part in the pressurized vessel separatable into plural pieces is divided into a high pressure chamber 1a and low pressure chamber 1b through a shelter member having a pouring hole. In the case the starting is executed at lower pressure than the pressure of low pressure casting executed with the higher pressure than the atmosphere pressure by the prescribed pressure, the melting furnace or the holding furnace is set in a high pressure chamber in the pressure vessel filled up with inert gas, etc., pressure-controlled in the high pressure, and by executing the temp. control to the molten metal held, the molten metal can be poured into the mold laid in the low pressure chamber. Involusion of the oxidized molten metal of aluminum alloy, etc., into the mold at the time of pouring the molten metal, is prevented. Further, as the molten metal is poured into the mold in the low pressure chamber side from the melting furnace or the holding furnace in the high pressure chamber side, good gas vent from the mold is executed, and by increasing pressure as progressing the solidification, the defect of pin hole, shrinkage, etc., can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention mainly applies to aluminum alloys and magnesium alloys. The present invention relates to a casting method and apparatus for casting metal such as titanium alloy under reduced pressure or pressure in air or an inert atmosphere.

[Conventional technology]

Recently, various manufacturing methods for highly reliable aluminum alloy (hereinafter referred to as aluminum alloy) castings have been developed and diversified, and materials for important safety parts of automobile parts are also being made lighter by replacing steel with aluminum alloy castings. It is planned. For this reason,
Conventionally, even relatively large products have been cast using a low-pressure casting method that allows efficient production with good dimensional accuracy.

[Problem to be solved by the invention]

In casting using the above-mentioned low-pressure casting method, it is difficult to completely prevent casting defects when manufacturing thin-walled or thick-walled castings with complex shapes, or when using difficult-to-cast materials. In order to improve these problems, there is no solidification control means suitable for the various materials used, and entrainment occurs in the casting due to the generation of oxides due to turbulent flow of the molten metal and oxidation of the molten metal due to pressurized air. Mechanical properties and toughness are significantly reduced. In addition, pressurized air causes hydrogen gas to dissolve in the molten metal, causing bottle holes and microshrinkage defects, but it has been difficult to take countermeasures against these problems.

The present invention applies pressure as appropriate to the product shape, weight, and weight while the injected molten metal solidifies in the mold, and also controls the method of application. For example, (1) Molten metal can be appropriately replenished into the space during solidification and contraction.

■Do not leave gas in the molten metal in the casting after solidification.

■ Molten metal can sufficiently flow into thin gaps in the mold.

5 ■ The air layer between the mold and the molten metal is reduced, which facilitates cooling of the casting.

■The complicated shape makes it easy for the molten metal to branch out, which can prevent poor flow of the metal.

As described above, it is possible to eliminate the problems with the conventional low-pressure casting method, suppress the occurrence of the casting defects, and manufacture high-quality castings with high precision and high efficiency in response to various materials used. The purpose of this invention is to provide a casting method and device that can be used.

[Means to solve the problem]

As a result of various studies in order to achieve the above object, the present invention has been developed to increase the pressure over time in the air or in an inert gas atmosphere such as Ar or N2, thereby increasing the pressure (0 to lkgf) in the conventional low-pressure casting method. /cm2), and the temperature of the molten metal held in a melting furnace or holding furnace (concentration of atmosphere or inert gas, pressure, temperature of molten metal, etc.) We found that setting the optimum range in advance according to the material used is effective in suppressing the above-mentioned casting defects, developed a casting method to do this, and developed the equipment. I got it. The specific method for controlling the conditions is: ■ The injected molten metal is allowed to solidify sequentially starting from the part of the gap in the mold that is farthest from the injection port. Continuously controls mold cooling capacity. At the same time, a suitable casting plan is also developed.

■In order to properly supply molten metal to areas where internal pressure changes are large and casting defects are likely to occur, pressure is applied until solidification is completed after pouring the molten metal, and the way in which it is applied (pressure rise per hour) can cause defects. Adjust as you like so that it does not drop.

■When starting pressurization control (hereinafter referred to as star 1-), the pressure should be reduced or increased. Which method to use depends on the object to be used and the required quality level, but especially if it is necessary to reduce the gas in the molten vortex, start under reduced pressure and gradually increase the pressure.

In particular, item (5) is the key point of the present invention.

The first invention of the present application provides a melting furnace or a holding furnace and a mold in a pressure vessel. This is a pressure-added casting method characterized by casting in the pressure vessel and controlling the pressure in conjunction with the progress of solidification of the casting.

The second invention is a melting furnace or a melting furnace having a means for controlling the amount of molten metal poured into one mold and a means for heating and insulating the mold in a pressure vessel that can be separated into a plurality of pieces and communicates with a pressure source and a depressurization source as necessary. A holding furnace is provided, and a pressure control means for controlling the pressure in the pressure vessel, and a temperature control means for controlling the temperature of the molten metal in the melting furnace or the holding furnace via the heating/warming means. This is a pressurized addition casting equipment.

The third invention is that the inside of the pressure vessel can be separated into a plurality of parts.
The system is divided into a high-pressure chamber that communicates with a pressurizing source as necessary and a low-pressure chamber that communicates with a depressurizing source as necessary via a shutoff member having a pouring port, and a means for controlling the amount of poured hot water and a means for heating and keeping warm are installed in the high-pressure chamber. A melting furnace or a holding furnace is provided, and a pressure control means that enables the mold to be accommodated in a low pressure chamber and controls the pressure of the high pressure chamber and the low pressure chamber, and a pressure control means that controls the temperature of the molten metal in the melting furnace or the holding furnace. This pressurizing {=J casting apparatus is characterized in that it is provided with a temperature control means that is controlled via the heating/warming means.

The fourth invention is... A high-pressure side pressure vessel that can be separated into multiple units and communicates with a pressure source as necessary, and a low-pressure side pressure vessel that can be separated into multiple units and communicates with a reduced pressure source as necessary, are installed together.
A melting furnace or a holding furnace having heating and heat retention means is installed in the high-pressure side pressure vessel. The mold can be housed in the low-pressure side pressure vessel. A pressure control means for controlling the pressure in the high-pressure side pressure vessel and the low-pressure side pressure vessel, which includes a pouring pipe that communicates between the vicinity of the bottom of the melting furnace or the holding furnace and the sprue of the mold; The pressurized addition casting apparatus is characterized in that it is provided with a temperature control means for controlling the temperature of the molten metal in the melting furnace or the holding furnace via the heating/warming means.

The fifth invention is a pressure vessel that can be separated into two or more parts.
By means of a blocking member on which the mold can be placed. 9. Divided into an upper high pressure chamber that communicates with a pressure source as necessary and a lower low pressure chamber that communicates with a reduced pressure source as necessary, and an opening that allows gas to pass through the mold when the mold is placed on the blocking member. is provided in the blocking member, and a melting furnace or a holding furnace is provided in the upper high-pressure chamber having a means for controlling the amount of molten metal poured into the chamber and a heating and heat-retaining means, and a pressure control means for controlling the pressure in the upper high-pressure chamber and the lower low-pressure chamber. and. The pressurized addition casting apparatus is characterized in that it is provided with a temperature control means for controlling the temperature of the molten metal in the melting furnace or the holding furnace via the heating/warming means.

The sixth invention is... When casting metal using the pressurized addition casting apparatus according to any one of claims 2 to 5, the pressure in the mold is kept under reduced pressure or under increased pressure during pouring,
This is a pressurized addition casting method characterized by increasing the pressure within the mold over time.

[Effect]

In each of the above-mentioned inventions, the starting pressure is negative compared to low-pressure casting which is performed at a pressure O~1 kgf10/cm2 higher than the conventional atmospheric pressure. A melting furnace or a holding furnace is installed in a high-pressure chamber of a pressure vessel filled with an inert gas, etc. that is pressure-controlled at high pressure, and the temperature of the held molten metal is controlled and poured into a mold placed in a low-pressure chamber. It is now possible to do so. Therefore. It can prevent molten metal such as aluminum alloy from being oxidized and being rolled into the mold during pouring.
In addition, since the metal is poured from the melting furnace or holding furnace on the high-pressure chamber side toward the mold on the low-pressure chamber side, degassing from the mold is easy.
Also. By increasing the pressure as solidification progresses, casting defects such as pinholes and ring gauges can be prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 7.

(Embodiment 1) Fig. 1 is a sectional view showing the first embodiment of the present invention, and
The figure is a diagram showing a control system.

In FIG. 1, reference numeral 1 denotes a pressure vessel that can be separated into two upper and lower parts at the center, and is connected to a pressurization source and a depressurization source (none of which are shown) through an air supply pipe 11 and an exhaust pipe 12, respectively. The internal air is removed via a decompression source and the pressure is reduced to below atmospheric pressure if necessary, and the pressure is reduced to below atmospheric pressure via a pressurization source. By supplying the atmosphere or an inert gas such as Ar or N2, for example by replacing 80% of the internal volume, the pressure is increased to 30 kgf above atmospheric pressure.
It is possible to pressurize and fill up to a pressure of about /cm2. 2 is. This is a crucible-shaped holding furnace for molten aluminum alloy, which is installed in a relatively upper part of the pressure vessel l.It has a heater 3 on the outside that can control the temperature for heating and keeping warm, and has a heater 3 on the inside that can control the temperature. For example, the recording device 4a
It has a stopper 4 that moves up and down by the stopper 4 to control the amount of molten metal poured into the mold 10 placed below. Furthermore, as shown in FIG. 2, a pressure control device 5 for controlling the pressure inside the pressure vessel 1 and a temperature control device 6 for controlling the temperature of the molten metal in the holding furnace 2 via the heater 3 are provided.

By using a casting device with the above structure. For example, when casting aluminum alloy castings using a sand mold 10, the upper part of the pressure vessel 1 is separated at the center. The mold 10 is lifted and removed using a crane or the like using the hook l3, and the mold 10 is placed at the bottom of the pressure vessel 1.
Place.

Next, a holding furnace 2 having a heater 3 on the outside is installed on the mold 10 (the holding furnace 2 may be installed on the mold 10 in advance and installed at the same time as the mold 10 is placed). At the same time, the switch 1/bar 4 and the rehearsing device 4a to operate it are also installed at the same time.

Next, a separately melted molten aluminum alloy is poured into the holding furnace 2, and the molten metal is maintained at a predetermined temperature via the temperature control device 6, and the upper part of the pressure vessel l that was removed is again covered and firmly connected to the lower part. Join.

Next, as shown in FIG. 2, the vacuum pump 16
Vacuum tank l that has become evacuated to about O ””mmllg
By 7. The air inside the pressure vessel 1 is removed through the exhaust pipe 12, and Ar gas is supplied into the pressure vessel 1 through the air supply pipe 11 from the pressurized tank 18 filled with Ar gas at a high pressure of approximately 20 kgf/C. Pressure 13: About 80% of the internal volume of the container 1 is replaced with high pressure Ar gas. Thereafter, the pressure of the Ar gas is controlled to a predetermined pressure by the pressure control device 5, and the stopper 4 is raised to open the outlet at the bottom of the holding furnace 2, and the melt is poured into the mold 10.

after that. The pressure is increased as necessary as coagulation progresses. Note that this situation is illuminated through the lighting window 14 provided at the top of the pressure vessel 1. It is possible to observe through the observation window l5 (however, these windows may not be provided).

The aluminum alloy castings cast as described above were inspected and were found to be of excellent quality, with no defects such as oxide entrainment, pinholes, or shrinkage, as described below.

In addition, in this embodiment, an example in which the pressure vessel 1 is separable into two parts, an upper and a lower part, has been described, but this may be made so that it can be separated into three or more parts, and the same applies to the following embodiments. be. In addition, an example was shown in which the amount of poured molten metal is controlled by the stopper 4. Of course, this may be done by other means l4, such as using a sliding gate or tilting the holding furnace 2, and the same applies to the following embodiments.

Furthermore, although the holding furnace 2 has been described as one that receives separately melted molten metal and holds it at a predetermined temperature, this holding furnace 2
may be a melting furnace that also serves as a melting furnace (or conversely, a melting furnace that also serves as a holding furnace). That is, for example, instead of the heater 3, an induction heating furnace may be used to melt the aluminum alloy. The molten metal may be maintained at a predetermined temperature thereafter. This also applies to the following examples, 5 and in this specification.
All references to ``holding furnace'' refer to this, ie, ``melting furnace or holding furnace.''

Next, aluminum alloy castings were cast using the above casting equipment.
The results of evaluation of casting defect 5 mechanical properties and others will be described in detail.

3 is a plan view showing a model of the test piece, and FIG. 4 is a side view taken in the direction of arrow D in FIG. 3. 21 to 24 in both figures
are test pieces, each having a planar shape of 100 mm.
Shape it into a square of 100 mm x 3 mm in thickness. 1 0mm, 1 5mm, 3
A casting method was used in which the sprue 25 was connected via a runner 26 and a weir 27. That is, the test piece 21 is an aluminum alloy casting with a minimum wall thickness of 3 mm, and the test piece 24 is an aluminum alloy casting with a maximum wall thickness of 30 mm. Specimens 22 and 23 each have a medium wall thickness of 1
This assumes 0mm and 15mm. Next, numerals 28 to 33 are bosses, each of which has a shape that is often used, for example, in automobile castings, and each has the dimensions shown in the table. Further, numerals 34 to 37 are feeders, respectively, which were provided to prevent shrinkage due to shrinkage during solidification of the test specimens 2l to 24, and each had the dimensions shown in the table.

A CO2 mold was made using the model of the above test piece, and molten aluminum alloy was poured into it. In this case, the riser 34 or 3
A heat insulating material was provided around the outer circumference of 7 to promote the feeder effect. Note that AC1B was used as the aluminum alloy. This alloy is an A12-Cu alloy, and although its strength can be increased by heat treatment, it has extremely poor castability, making it a difficult-to-cast material that has not been able to produce sound castings in the past.

After casting, the riser and boss sections were longitudinally sectioned, and the fractured surfaces were investigated for pinholes and other defects by penetrant testing.

Figures 5 to 7 are diagrams schematically showing the results of penetration deep damage tests on the fracture surface of test pieces, respectively; the one shown in Figure 5 is the one cast under atmospheric pressure, Each figure is 6k
This corresponds to the one cast under pressure of 9 kgf/cm2 and 9 kgf/cm2.First, in Fig. 5, test piece 2
All of the bosses 28 to 33 are found to have pinholes or cavities, and in particular, a large number of defects have occurred in the bosses 28 to 33, making them completely unusable as a cast product. This clearly shows that ACIB material is a difficult-to-cast material as mentioned above, and it is completely impossible to cast a sound casting by casting under atmospheric pressure, that is, by conventional casting methods. There is. Next, in Figure 6, 6
In the thin test piece 21, there were almost no pinholes in the flat plate part, and only a few pinholes were found near the tops of the bosses 28 and 29. In test specimens 22 and 23, the presence of pinholes was recognized, but relatively large shrinkage cavities were found in feeders 35 and 36, and test specimen 2
It is understood that the molten metal replenishment action to 2.23 is being carried out well. Although a large number of pinholes or nests are still observed in the test piece 24 where the wall thickness has been reduced to almost the maximum, the area ratio is smaller than that shown in FIG. 5. From this, it is understood that applying pressure during casting is effective in reducing pinholes or porosity.

Furthermore, in the case shown in Fig. 7, the applied pressure is 9 kgf/cm"
It can be seen that the number of bin holes and porosity has been significantly reduced overall18. In particular, only a few fine pinholes were observed in test pieces 21, 22, and 23. Test piece 2
Although there are still a large number of pinholes in 4, it can be seen that the area ratio has been drastically reduced compared to those shown in FIGS. 5 and 6. Such a phenomenon has never been experienced in conventional casting of ACIB, which is a difficult-to-cast material. It is understood that the pressure applied during casting greatly contributes to the soundness of the casting. In other words, the application of pressure to the mold and molten aluminum alloy during casting suppresses the formation of pinholes, cavities, and porosity. It is presumed that the molten metal has the effect of promoting the replenishment of molten metal from the riser during collapse and contraction.

Figures 8(a) and 9(b) are diagrams showing the relationship between pressurizing pressure, tensile strength, and elongation for AC4B, respectively.Figure 9(a)
(b) are diagrams (a) and (b) showing the relationship between pressurizing pressure, tensile strength, and elongation for AC4C, respectively.
are diagrams showing the relationship between pressurizing pressure, tensile strength, and elongation for ACIB, respectively, and the test pieces 23 and 24 shown in FIGS. 3 and 4 above are
The values shown are based on test beads taken from the flat plate part of. In these figures, F is the value for the as-cast T6 and the heat-treated one, and the value in parentheses is the thickness (unit: mm) of the flat plate portion of the test piece 23.24. In these figures, the heat-treated T6 has higher values than the as-cast F, except for the elongation shown in Figure 9(b), which is due to precipitation hardening of MgzSi due to solution treatment and aging treatment. It shows a natural result. Also, the values for the 15mm thick ones are higher than those for the 30mm thick ones. This is believed to be the result of a relatively fine crystal grain size because the solidification cooling rate is relatively high in the case of smaller wall thicknesses. Next, there is a tendency for tensile strength and elongation to increase as pressure is applied during casting, and as the pressure increases. Figures 8(a)(b) and 9(
In AC4B and AC4CH shown in a) and (b), the increasing tendency is relatively gradual. This is because both of the above alloys inherently have good castability. This is because predetermined mechanical properties can be obtained even by casting under atmospheric pressure of 20%. On the other hand, in the ACIB shown in FIGS. 10(a) and 10(b), the influence of pressurizing pressure is extremely significant. This is because, as mentioned above, ACIB is a difficult-to-cast material, and when cast under atmospheric pressure, it contains many cavities, pinholes, and porosity as shown in FIG. 5 above. However, by applying pressure and increasing the applied pressure, the above-mentioned internal defects are significantly reduced (see Figures 6 and 7). Recognized as increasing health. It is understood that the application of pressure contributes greatly.

FIG. 11 (aHb> is a diagram showing the relationship between the applied pressure and the porosity area ratio, respectively. The test bead taken from the flat plate part (wall thickness 301llI) of the test piece 24 shown in FIGS. 3 and 4 above. This is due to

Note that FIG. 11(a) corresponds to a case in which the metal was poured under atmospheric pressure and rapidly pressurized, and FIG. 11(b) corresponds to a case in which the metal was cast after reaching a constant pressure. As is clear from both figures, the porosity area ratio decreases with the application of pressure and an increase in the applied pressure, and the porosity area ratio shows a value below 0.5% by applying the applied pressure of 9 kgf/cm2. 7. Soundness has improved significantly. Even in AC4B and AC4CH, which are said to have relatively good castability, it is recognized that applying pressure and increasing the pressurizing pressure is effective. Regarding the manner of applying pressure, for ACIB, when casting is performed after reaching a certain pressure (Fig. 11 (b)
) is recognized to be more effective for reducing the porosity area ratio, but no significant difference is observed between FIGS. 11(a) and (b) for AC4B and AC4CH.

FIGS. 12(a) and 12(b) are diagrams showing the relationship between pressurizing pressure and density, and correspond to FIGS. 11(a) and (b), respectively. In other words, Figure 12(a) shows the case where the metal was poured under atmospheric pressure and rapidly pressurized. FIG. 12(b) corresponds to those cast after reaching a constant pressurization pressure. As is clear from both figures. It is observed that by applying pressure and increasing the pressurizing pressure, the density is improved compared to that cast under atmospheric pressure. Regarding ACIB and AC4CH2
For AC4B, it is recognized that the density is slightly higher for those cast after reaching a certain pressure, but no significant difference is observed for AC4B. After pouring the molten metal, some time elapses before pressurization starts, and solidification begins in the area that comes into contact with the two mold cavities, forming a film. It is understood that the mode shown in FIG. 12(b), that is, the casting after reaching a constant pressurizing pressure is preferable.

Next, Figure 13 (aHb) and (c) are AC4BAC4C, respectively.
A diagram showing the relationship between pressurization timing and density for H and ACIB, Figure 13 ((1) is a diagram showing the cooling curve of molten metal. First, in Figure 13 (L), T., T., T3 ,T
．． -. represents the time of pouring, the start of solidification of molten metal, the time of 50% solid/liquid, and the end of solidification, respectively. Figure 13(a)(b)(c)
5, which corresponds to the symbol on the horizontal axis, are values based on test pieces taken from test pieces with a thickness of 30 mm. First, in AC4B shown in Fig. 13(a), T1 at the time of 2 pouring
When pressurized at . The density of 23 degrees is higher than that under atmospheric pressure, and the density decreases as the pressurization period is delayed. The AC4CH shown in FIG. 13(b) has a similar tendency to that shown in FIG. 13(a).

Next, for ACIB, which is a difficult-to-cast material shown in Figure 13(c), it is expected that the density will improve by applying pressure.
If pressure is applied at time T4, that is, at the end of solidification of the molten metal, no improvement in density can be expected. Figure 13(a)(b)
Overall, it is recognized that it is preferable to apply pressure at the time of pouring in order to improve density.

Figure 14 (a), (b), and (c) are AC4B and AC4, respectively.
It is a figure showing the relationship between the pressurization timing and the porosity area ratio for CH and ACIB, both of which have a thickness of 30InlI1.
This value is based on a test bead taken from a test piece cast at a pressure of 9 kgf/cm2.

As is clear from these figures, as the pressurization period is delayed, the porosity area ratio increases, which impedes the soundness of the casting. In particular, for ACIB shown in Fig. 14(c), when the pressure is applied at T1 during pouring, 0.5%
Whereas. Coagulation 24 At T4 at the end of coagulation, the value increases to more than 3%. Therefore, in order to expect the porosity prevention effect due to pressure application, it is recognized that it is preferable to apply pressure at the time of pouring.

(Embodiment 2) FIG. 15 and FIG. 16 are sectional views each showing a second embodiment of the present invention.

In both figures, a blocking member 7 is provided in the center of a pressure vessel 1 that can be separated into upper and lower parts, and the - side is a high pressure chamber 1a (the upper part in Fig. 15 and the lower part in Fig. 16), and the other part is a low pressure chamber lb ( The lower part in FIG. 15 and the upper part in FIG. 16 communicate with the pressurizing source and the depressurizing source, respectively, as necessary. A temperature-controlled holding furnace 2 is installed in the high pressure chamber la, and a mold 1 is placed in the low pressure chamber lb.
0 can be accommodated and placed. Further, although not shown, a temperature and pressure control device is provided in the same manner as in the first embodiment. When casting, the air in the low pressure chamber ib is removed to reduce the pressure, and the high pressure chamber la is pressurized by supplying high pressure Ar gas to maintain the temperature of the molten metal in the holding furnace 2 as in Example 2. While controlling the pressure inside each chamber 25 la, lb, the sliding gate 4
Open ′. When the holding furnace 2 is installed in the lower part as shown in FIG. 16, pouring is performed by pressurizing force through the stalk 8.

Thereafter, as the solidification progresses, the pressure on the low pressure chamber lb side is increased as necessary.

In this example as well, the aluminum alloy casting after casting was of the same high quality as in Example 1.

(Embodiment 3) FIG. 17 is a sectional view showing a third embodiment of the present invention. In this example, the high-pressure side pressure vessel IA and the low-pressure side pressure vessel I
B, and communicate with the pressurization source and depressurization source as necessary. A temperature-controlled holding furnace 2 is installed in the high-pressure side pressure vessel IA, and a mold 1 is installed in the low-pressure side pressure vessel IB.
0 can be accommodated and placed. Further, a pouring pipe 9 made of ceramic material is provided which communicates between the vicinity of the bottom of the holding furnace 2 and the sprue of the mold 10. Further, although not shown, temperature and pressure control devices are provided in the same manner as in the first embodiment. When performing casting. While controlling the temperature of the molten metal in the holding furnace 2 as in Example 1, the pressure vessel IB on the low pressure side
The molten metal in the holding furnace 2 is poured into the mold 10 via the 2 pouring pipes 9 by reducing the pressure inside the holding furnace 2 and pressurizing it with Ar gas in the high-pressure side pressure vessel IA while controlling the pressure. after that. The sliding gate 4' is closed, and as the solidification progresses, the pressure on the low-pressure side pressure vessel IB side is increased as necessary.

In this example as well, the aluminum alloy casting after casting was of the same high quality as in Example 1.

(Embodiment 4) FIG. 18 is a sectional view showing a fourth embodiment of the present invention. In this embodiment, as shown in FIG. 18, the pressure vessel 1 is divided by a blocking member 7 into a high pressure chamber 1a in the upper part and a low pressure chamber 1b in the lower part. It communicates with a pressurization source and a depressurization source, respectively.

However, the center of the blocking member 7 is lowered and the mold 10
When the mold 10 is placed, there is an opening through which the gas in the high pressure chamber Ia can pass in the direction of the arrow through the mold 10 and through the hole 10b at the bottom of the flask 10a. 7a is provided. Further, although not shown, a temperature and pressure control device is provided in the same manner as in Embodiment 1.

When casting, place the mold 1 on the lowered part of the blocking member 7.
0 is placed, and the holding furnace 2 is installed on top of it. Then, while controlling the temperature of the molten metal in the holding furnace 2, the pressure in the low pressure chamber lb is reduced and the pressure in the high pressure chamber la is increased.Furthermore, while controlling these pressures, the sliding gate 4' is opened. The molten metal in the holding furnace 2 is poured into the mold 10. At this time, the Ar gas in the high pressure chamber la and the gas generated during casting pass through the mold 10. Furthermore, it passes through the hole 10b in the bottom of the flask 10a and exits from the opening 7a of the blocking member 70 into the low pressure chamber lb. After that, as the solidification of the casting progresses, the high pressure chamber la is installed as necessary.
Increase the pressure on the side.

The algo alloy casting obtained in this example also had the same high quality as in Example 1.

(Example 5) FIG. 19 is a diagram showing an example of a pressure control pattern when casting is performed using the casting apparatus described in Examples 1 to 4 above. On this occasion of metal casting. The air inside the pressure vessel is removed via a decompression source over the required time L1, and the pressure inside 5 is reduced to below atmospheric pressure (in this example, -1 kgf/cm2).
) and maintain this state for an appropriate time t2. At point A, the atmosphere is replaced with the atmosphere or an inert gas such as Ar gas or N2 gas, and then a predetermined pressure (4 kgf/cm'' in this example) is applied for the required time L via a pressurizing source. Pressure is applied to the mold, and pouring is carried out at point B within a certain period of time.After that, as time passes, the solidification of the liquid in the mold progresses, and as this progresses, the pressure at which the mold is placed increases. The pressure inside the container is increased as indicated by arrow CI or C2 in FIG. 19 over an appropriate time t4 (in this example, approximately 10 kgf/cn+2).
)? Alternatively, the pressure during pouring is maintained as shown by arrow C4.

In addition. The pressurizing force during pouring may be relatively low, such as about 2 kgf/cm2, as shown by the dotted line in FIG. 19, or it may be quite high, such as 11 kgf/cm2. Although not shown, it may be under negative pressure below atmospheric pressure or under atmospheric pressure.

For example, the control of pressure using the Pacoon shown in Figure 19 depends on the material used and the shape of the casting to be cast. Determined based on dimensions, plan, etc.

By controlling the pressure as described above, we were able to produce high-quality castings.

〔Effect of the invention〕

As described above, according to the present invention, oxides can be incorporated and processed in accordance with each material without being limited to the materials used.
The occurrence of casting defects such as bottle holes and shrinkage can be suppressed. For example, it is lightweight, highly reliable, and of excellent quality as an important safety component for automobiles. Moreover, high-precision products can be manufactured efficiently. Note that the present invention is not limited to aluminum alloys, but can also be used for casting magnesium alloys, titanium alloys, etc., and can achieve the same effects as described above.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of the present invention. Fig. 2 is a control system diagram, Fig. 3 is a plan view showing a model of the test piece, Fig. 4 is a side view taken in the direction of arrow D in Fig. 3, and Figs. 5 to 7 are each a test piece. Figures 8 (a) and 8 (b) are diagrams schematically showing the results of penetration deep damage tests on the fracture surface of AC4B, respectively. Figure 9 ( Figures a) and (b) are diagrams showing the relationship between the applied pressure and tensile strength and elongation for ACIB, respectively. Diagram showing the relationship between strength and elongation, Part I
Figures 1 (a) and (b) are diagrams showing the relationship between pressurization pressure and volocity area ratio, respectively, and Figures 12 (a) and (b) are diagrams showing the relationship between pressurization pressure and density, respectively. Figure 13(a)(b)(C)
are diagrams showing the relationship between pressurization timing and density for AC4B, AC4CH, and ACIB, respectively, Figure 13 (d) is a diagram showing the cooling curve of molten metal, and Figure 14 (a), (b), and (c) are diagrams for AC4B, respectively. , FIG. 15 and FIG. 16 are cross-sectional views showing the second embodiment of the present invention, and FIG. 17 is a cross-sectional view showing the third embodiment of the present invention. FIG. 18 is a cross-sectional view showing an example of the 31st embodiment of the present invention, and FIG. 19 is a view showing an example of a pressure control pattern when casting using the casting apparatus of the present invention. . 1: Pressure vessel IA: High pressure side pressure vessel 1B: Low pressure side pressure vessel 1a: High pressure chamber 1b = low pressure chamber 2: Holding furnace 3: Heater 4: Sliding gate 4': Sliding gate 5: Pressure control device 6: Temperature control device W
7: Blocking member 7a: Opening 8: Stoke 9: Molten pouring pipe lO: Mold 11: Air supply pipe l2: Exhaust pipe 16: Vacuum pump 17: Vacuum tank l8: Pressure tank

Claims (6)

[Claims] (1) A pressurized addition casting method, characterized in that a melting furnace or a holding furnace and a mold are provided in a pressure vessel, casting is performed in the pressure vessel, and pressure is controlled in conjunction with the progress of solidification of the casting. (2) A melting furnace or a holding furnace having a means for controlling the amount of molten metal poured into the mold and a means for heating and insulating the mold is installed in a pressure vessel that can be separated into multiple parts and communicates with a pressure source and a depressurization source as necessary. and a pressure control means for controlling the pressure in the pressure vessel, and a temperature control means for controlling the temperature of the molten metal in the melting furnace or the holding furnace via the heating/warming means. Pressure addition casting equipment. (3) The interior of the pressure vessel, which can be separated into a plurality of parts, is divided into a high-pressure chamber that communicates with a pressure source as necessary and a low-pressure chamber that communicates with a reduced pressure source as necessary via a blocking member having a pouring port, A melting furnace or a holding furnace having means for controlling the amount of molten metal poured into the chamber and heating and heat-insulating means is provided in the high-pressure chamber, and a pressure control means that enables the mold to be accommodated in the low-pressure chamber and controls the pressures in the high-pressure chamber and the low-pressure chamber. A pressurized addition casting apparatus comprising: a temperature control means for controlling the temperature of the molten metal in the melting furnace or the holding furnace via the heating/warming means. (4) A high-pressure side pressure vessel that can be separated into a plurality of pieces and communicates with a pressure source as necessary, and a low-pressure side pressure vessel that can be separated into a plurality of pieces and communicates with a reduced pressure source as necessary, are installed together, and the high-pressure side A melting furnace or a holding furnace having heating and heat-insulating means is provided in the pressure vessel, and a mold can be accommodated in the low-pressure side pressure vessel, so that the vicinity of the bottom of the melting furnace or holding furnace and the mold are a pressure control means that includes a pouring pipe that communicates between the sprues and controls the pressure in the high-pressure side pressure vessel and the low-pressure side pressure vessel; A pressurized addition casting apparatus characterized by being provided with a temperature control means controlled via a heat retention means. (5) The interior of the pressure vessel, which can be separated into multiple parts, is divided into an upper high-pressure chamber that communicates with a pressure source as necessary and a lower low-pressure chamber that communicates with a reduced pressure source as necessary, using a blocking member on which a mold can be placed. A melting furnace that is divided into parts, and has an opening in the blocking member that allows a gas to pass through the mold when the mold is placed on the blocking member, and has a means for controlling the amount of molten metal poured into the upper high-pressure chamber and a means for heating and keeping warm. Alternatively, a holding furnace is provided, and a pressure control means for controlling the pressure in the upper high pressure chamber and the lower low pressure chamber, and a temperature control means for controlling the temperature of the molten metal in the melting furnace or the holding furnace via the heating/warming means. A pressurized addition casting device characterized by being provided with. (6) When casting metal using the pressurized addition casting apparatus according to any one of claims 2 to 5, the pressure in the mold is reduced or increased during pouring, and as time passes, A pressurized addition casting method characterized by increasing the pressure within the mold.