JPS59156564A - Casting method and device - Google Patents

Abstract

PURPOSE:To maintain an apparatus and to improve the quality of a product in a low pressure casting method by communicating a ladle for a molten metal and the chamber in a casting mold with each other to equalize the pressure in the stage of replacing the inside of the ladle and the casting chamber with a vacuum and inert gas. CONSTITUTION:A temporally chamber 15 is formed of a housing 16 via a partition plate 3 above a ladle 2 for a molten metal, and after the inside thereof is evacuated with a vacuum pump 10 by the operation of valves 8, 8' and 9, 9' via pipelines 17, 18, the inside is replaced with gaseous Ar from a gas cylinder 11. A communicating hole 19 consisting of a through-hole is pierced in the plate 3, and the space 6 in the ladle 2 is communicated with the chamber 15 to equalize the pressure. The housing 16 is removed and a plug is inserted into the hole 19 to close the chamber. A chamber which contains a casting mold placed on a movable molding board and is subjected separately to a vacuum-gaseous Ar replacement in this state is installed on the plate 3 and the inside of the ladle 2 is pressurized to perform a casting operation through a stalk 12.

Description

[Detailed Description of the Invention] [Original Field of the Invention] The present invention relates to a low-pressure or pressure casting method in which a mold and a molten metal pot are placed in an inert atmosphere, and high-top casting with strong oxidizing aftershocks is performed. The present invention relates to equipment, and particularly to a casting method and equipment that can improve casting quality and operability.

[Prior art]

Conventionally, as seen in JP-A No. 55-136555, for example, the inside of the bathing pot and the inside of the mold chamber installed above the molten metal pot are once evacuated, and then replaced with an inert gas, such as Ar gas, and then Low-pressure casting that supplies molten metal to the mold via a Stokes that communicates the molten metal with the mold by pressurizing the inside of the molten metal pot, thereby casting products that require high precision. The law is known.

To explain this method in detail with reference to Figure 1, the bath water 1
A mold chamber housing 4 and a mold 5 are installed with a partition plate 3 interposed above the bath water @2 containing the mold chamber.

In this state, the space 6 inside the molten metal pot 2 and the inside of the mold chamber 7?
When operating the pulps 8, 9, etc., they are first evacuated using the vacuum pump 10. After this, the space 6 and the mold chamber 7 are replaced with Ar gas from the gas cylinder 11. After that, close the pulp 8' on the mold chamber side,
By opening only the pulp 9' on the side of the space 6 in the molten metal pot 2 and pressurizing this space 6, the bath water 1 is pushed up and supplied into the mold 5 through the Stokes 12. After the molten metal has solidified in the mold 5, the pressure in the space 6 in the molten metal pot 2 is released, the bath water level in the Stokes 12 is lowered, the mold chamber housing 4 and the mold 5 are replaced, and the above operations are performed. I try to repeat it.

However, in such conventional low-pressure casting methods, the molten metal ladle 2 and the mold chamber 7, which are vertically partitioned by the partition plate 3, are subjected to a vacuum-inert gas replacement operation through separate routes. Running pressure is likely to occur due to the resistance pressure and capacitance difference of the supply pipe, and this causes an inconvenience in that f6 positive air blows up from the Stokes 12. In general, this Makabe-inert gas replacement operation could be performed carefully based on the skillful operation of the pulps 8 and 8', 9 and 9', and the accuracy of the pressure gauges or pressure sensors 13 and 14. pressure gauge or pressure sensor 13,
Due to the sensitivity and accuracy of 14, it is difficult to quickly catch the differential pressure. In addition, it is difficult to completely eliminate the differential pressure when operating the pulps 8, 8', 9, and 9' even by a highly skilled person.

When a pressure difference is generated between the space 6 in the melting pot 2 and the space 7 in the mold chamber, albeit a small one, the molten metal in the Stokes 12 instantly fills the mold 5 with light. This careless injection causes problems such as defective products and complicated post-processing.

On the other hand, in such a conventional low-pressure casting method, a mold chamber is installed on a molten metal furnace, and these spaces are collectively replaced with vacuum and inert gas for each product. However, if vacuum-inert gas replacement was performed for each product,
There are problems in terms of quality assurance, such as fluctuations in the composition of the molten maple, air contamination in the Stokes during vacuum evacuation, and the inability to remove sludge, as well as poor productivity. It was.

Furthermore, in conventional low-pressure casting equipment, the Stokes are tightly attached to the mold, and there are no ventilation holes in the mold, so even if the pressure in the molten metal pot is removed after pouring, the molten metal in the Stokes will not melt. The problem was that the surface did not descend quickly. Particularly when using metal molds or applying pressure to preheat Stokes before casting, the level of the molten metal could not be raised or lowered quickly, resulting in poor work efficiency.

[Purpose of the invention]

The first purpose of the casting method and apparatus according to the present invention is to reliably prevent the generation of differential pressure when replacing the inside of the molten metal pot and the inside of the mold chamber with vacuum and inert gas, thereby maintaining equipment maintenance and product quality. The aim is to improve.

The second purpose is to improve the efficiency of casting work associated with mold replacement, to reduce the occurrence of two-skin in the Stokes during mold replacement, and to improve product quality by facilitating the removal operation. .

A third purpose is to improve operability by making it possible to quickly raise and lower the level of the bath water when preheating the Stokes before casting, as well as lowering the level after casting.

[Summary of the invention]

In the V8 manufacturing method according to the first aspect of the present invention for achieving the first purpose, the inside of the molten metal pot and the inside of the mold chamber installed above the molten metal pot are once evacuated, and then heated with an inert gas. In the casting method, the bath water is supplied to the mold via a Stokes that communicates the bath water with the mold by pressurizing the inside of the hot water pot. During replacement, the molten metal pot and the inside of the mold channel are made to retard each other to equalize the pressure.

Preferably, the communication operation between the molten metal pot and the mold channel is started at an early stage of internal vacuuming of the molten metal pot and the m-shaped chamber.

In addition, the communication operation between the molten metal pot and the L# & mold chamber is terminated when the inside of the molten metal pot and the mold chamber are brought to atmospheric pressure by inert gas.

The casting apparatus according to the second aspect of the present invention that carries out such a method includes a molten metal ladle containing bath water, a mold chamber provided above the molten metal ladle via a horizontal partition plate, and a mold chamber provided within the mold chamber. a mold housed in the chamber, a Stokes for supplying molten metal that communicates the mold with the molten metal pot, a vacuum equipment connected to the molten metal pot and the mold chamber to evacuate the inside of these, and gas exchange equipment for converting the molten metal into gas; a communication means for pressure equalization that communicates the molten metal ladle with the mold chamber; and a pressurizer that pressurizes the inside of the molten metal ladle to apply pressure for supplying the molten metal into the mold. The structure includes a pressure means.

In a preferred embodiment of such a casting apparatus, the communication means is constituted by a through hole formed in the partition plate and an opening/closing member for opening and closing the through hole.

Further, the casting method for achieving the third or second object of the present invention is to install a mold and a mold chamber on a molten metal pot containing molten metal, and to fill these with inert scum, In the casting method, in which bath water is poured into the mold through a stoke by pressurizing the inside of the pot, and after making the pot, the hook mold is changed and the above operation is repeated. The molten metal pot and the mold chamber are filled separately before their assembly, while inert gas is charged into the Stokes, which is open at the top, when the mold is removed after casting.

According to a fourth aspect of the present invention, a casting apparatus for achieving the third object includes: a molten metal ladle containing molten metal; a mold chamber formed on the molten metal ladle via a horizontal partition plate; A mold housed in the mold chamber, a Stokes for supplying molten metal that communicates between the mold and the molten metal pot, a vacuum equipment that is connected to the molten metal pot and the mold chamber and evacuates the inside of these, and the inside of these. gas replacement equipment for replacing the molten metal with an inert gas, and pressurizing the inside of the molten metal pot to apply pressure for supplying the molten metal into the mold and removing the pressurizing pressure in the molten metal pot after the molten metal solidifies in the mold. A porous member is provided at the upper end of the Stokes to allow ventilation between the inside of the mold chamber and the inside of the Stokes, but to prevent flow of molten metal.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 to 6. Note that the same parts as those in FIG. 1 showing a conventional low-pressure casting apparatus will be described with the same reference numerals assigned to the corresponding parts in the figure, and redundant explanation will be omitted.

FIG. 2 shows the first embodiment.

Note that the following first to third embodiments correspond to the first and second embodiments of the present invention for achieving the first objective.

In the low-pressure casting method according to this embodiment, the vacuum-inert gas replacement operation kh is performed before mold-making and installation. That is,
First, a temporary chamber 15 is formed by a housing 16 on the molten metal pot 2 with the partition plate 3 interposed therebetween. Then, pipes 17 and 18 led out from the bath water@2 and the temporary chamber 15, respectively.
4- Through the operation of the pulps 8 and 8', 9 and 9', the vacuum is evacuated with the vacuum pump 10, and then A is evacuated with the gas cylinder 11.
After replacing the r gas, the mold and the housing for the mold chamber are installed and casting is performed via the Stokes 12. During Ar gas replacement, the temporary chamber 15 and the wall 6 in the molten metal pot 2 are made to communicate with each other to equalize the pressure.

In this embodiment, the diaphragm 3 is used as a communication means for pressure equalization.
A communication hole 19 made of a through hole is bored in the space 6 and the temporary chamber 15 through the communication hole 19 . After the Ar gas replacement is completed, the housing 16 for the temporary chamber is removed, and the plug (
(not shown) is inserted into the communication hole 19 by manual operation or the like,
The communication hole 19 is closed. In this state, separate vacuum
A chamber containing a mold (not shown) placed on a movable surface plate that has been replaced with At gas is placed on the partition plate 3, the inside of the molten metal pot 2 is pressurized, and a casting operation is started via the Stokes 12. After casting is completed, the mold and mold chamber are removed and the above-described operations are repeated.

According to the low-pressure casting method according to the above embodiment, in addition to the vacuum-Ar gas replacement, the inside of the molten metal ladle 2 and the temporary chamber 15 are communicated through the communication hole 19 formed in the partition plate 3. Even though the replacement operation is carried out through separate pipe lines 17 and 18, the pressure in the internal space is equal, so molten metal will not inadvertently blow up from within the Stokes due to pressure differences, and the vacuum can be safely maintained. As a result of Ar gas substitution, the low-pressure fI4 production process can proceed.

FIG. 3 shows a second embodiment. In this embodiment, the mold 5 and the fIAI type chamber 7 are installed above the bath water@2, and Makabe-inert gas replacement is performed. In this embodiment as well, a communication hole 19 is formed in the partition plate 3 in the same manner as in the first embodiment. The opening/closing member 20 can open and close the communicating hole 19 indirectly from outside the p-chamber by moving the plug 21 for opening and closing the communicating hole 19 from outside the chamber 7 by eye movement. This is how it was done. When performing vacuum-inert gas replacement, @21 is raised to the open position as shown in the figure to open and close the communication hole 19.

Then, the housing 21 is lowered into the vacuum-inert cast body after the exchange, and the through hole 19 is immediately closed. After that, bath @
Bath water is injected into the mold 5 through the υStokes 12 by pressurizing the inside of the mold 5.

In this method, the inert gasification process in the molten metal pot 2 can be carried out with the mold 5 installed, resulting in a reduction in work efficiency.

FIG. 4 shows a third embodiment. In this example, the second
Similar to the first embodiment shown in the figure, this embodiment is for a case where a temporary chamber 15 is temporarily installed before casting and vacuum-inert gas exchange is performed. In this embodiment as well, the partition plate 3 having the communication hole 19 is used to communicate the inside of the molten metal pot 2 and the temporary chamber 15. In this embodiment, a conduit 17 is provided only on the side of the temporary chamber 15, and the vacuum-inert gas replacement operation is performed via this conduit 171.

That is, through the communication hole 19, negative pressure or inert gas charging from the conduit 17 is applied to the space 6 in the molten metal ladle 2 at the same time as to the temporary chamber 15.

Specifically, molten metal 1 is stored in a molten metal pot 2, and the upper part of the frying pot 2 is closed with a partition plate 3 serving as a lid. A fixed surface plate 23 is integrally fixed onto the partition plate 3 with the communicating holes 19 communicating with each other. Next, insert the Stokes 12 into the fixed surface plate 23 and the center hole of the partition plate 3.
, the temporary chamber housing 16 is attached, and the vacuum pump 10 provided in the conduit 17 is operated to gently open the pulp 8.

After confirming that the temporary chamber 1-5 and the space 6 west of the molten metal pot 2 have reached a predetermined degree of vacuum using the pressure gauge 29 provided in the temporary chamber 15, the pulp 8 is closed and the Ar gas cylinder 11 as an inert gas cylinder is closed. The pulp 9 is gently opened, and the Ar gas is blown into the temporary chamber 15 and the molten metal pot 2 until the pressure reaches 1 atmosphere. After confirming that the pressure inside the temporary chamber 15 has reached 1 atm using the pressure gauge 24, the pulp 9 is closed, and then for the temporary chamber 15/Using 1
6 is removed, and a plug 21A as an opening/closing member is inserted into the communication hole 19.
Insert. Thereafter, a mold chamber and a mold (not shown) are installed on the fixed surface plate 23, and a pressurizing action is performed via a pressurizing conduit into the molten metal ladle 2 (not shown).
The molten metal may be poured into the mold via the molten metal.

According to such a method, the vacuum-Ar gas replacement operation can be performed quickly and conveniently without the risk of fluctuations in the level of the bath water 1 via the single pipe line 17.

The equipment for carrying out the above low pressure casting method is
As shown in FIGS. 1 to 3, a mold chamber 7 or a temporary chunk 15 is provided on the molten metal ladle 2 via a horizontal partition plate 3 between a molten metal ladle 2 that accommodates molten metal 1, and A mold, a Stokes 12 for supplying molten metal that communicates the mold 5 and the molten metal pot 2, and a pipe connected to the molten metal pot 2, the mold chamber 7, or the temporary chamber 15 and serving as vacuum equipment for evacuating the inside thereof. 17.18, the nokurupu 8 and 8', 9 and 9', the vacuum pump 10, the communication hole 19 as a pressure equalization communication means for communicating the inside of the molten metal pot 2 and the chamber 7.15, and the molten metal Pot 2 and chamber 7.15
Pipe 1 as gas replacement equipment to replace the inside with inert gas
7, 18, equipped with a gas cylinder 11, etc., and a pressurizing means (combined with the pump 10 or a pressurizing pump not shown) that pressurizes the inside of the bath pot and applies force for supplying the molten metal 1 into the mold 5. Find something to do. The communication hole 19 serving as a communication means for pressure equalization is provided with an opening/closing member including an opening/closing member 20, a plug 21, etc.

This unique device allows Nissin to carry out the low-pressure casting method described above. 7 In the above embodiment, the communication means for pressure equalization was the communication hole 19 provided in the partition plate 3, but the present invention is not limited to such a communication means. Although not shown in the drawings, the molten metal pot and the chamber are connected to a bypass pipe. It is also possible to use a configuration in which the channels communicate with each other using a path or the like.

FIG. 5 shows a fourth embodiment, which corresponds to the third embodiment.

In this embodiment, as shown in the first embodiment shown in FIG. After performing this, we replace the mold chamber and mold with an inert gas atmosphere in another location, and adopt a method to eliminate the efficiency loss when performing Makabe-inert gas replacement for each product. There is. In this case, the Stokes 12 is opened upward during the exchange of word forms to prevent air contact and to prevent the occurrence of phlegm. That is, in this embodiment, during the hook-shaped head exchange, the inert gas injection pipe 25 is introduced into the Stokes 12 from above, and Ar gas or the like is supplied as an inert gas to the surface of the molten metal 1 in the Stokes 12. I have to. This feeding operation is performed by the pulp 26 of the injection tube 25.

Specifically, once the space 6 inside the molten metal pot 2 becomes an inert atmosphere, it is sealed and there is no risk of air entering from the outside, but in the interior space 27 of the Stokes 12, it comes into contact with the atmosphere. Therefore, there is a risk of air intrusion. Since inert gas such as Ar gas has a higher specific gravity than air, it is generally possible to prevent oxidation to a certain degree, but it cannot be said that there is no effect of air flow. Therefore, until the mold with an inert atmosphere and the mold chamber are installed on the fixed surface plate 23, the inert gas injection pipe 25 is connected to the Stokes 12P1.
In this method, an inert gas, ie, Ar gas, is injected. Since Ar gas is heavier than air, it was confirmed that once the inside of Stokes 12 was filled with Ar gas, it was possible to deoxygenate for about 1 minute.

According to this embodiment, since the inside of the Stokes 12 can be reliably maintained in an inert atmosphere when replacing the mold, high quality castings can be obtained without generating oxides during casting.

FIG. 6 shows a fifth embodiment, which corresponds to the fourth aspect of the present invention.

In the low-pressure @-molding device according to this embodiment, the upper end portion of the Stokes 12 allows ventilation between the inside of the mold chamber 7 and the inside of the Stokes 12, but there is a porous member 2 that prevents the flow of the molten metal 1.
There are 8. That is, in this embodiment, the level of the molten metal within the Stokes 12 after casting can be lowered smoothly and quickly. To be more specific, if the pressure in the molten metal ladle 2 is lowered when the molten metal in the mold 5 has solidified, the molten metal with a Stokes of 12 yen will return to the level of the molten metal in the molten metal ladle 2, but the Stokes If all of the stokes 12 are made of metal and in close contact with the mold 5, the surface of the molten metal in the stokes 12 will not easily drop even if the pressure in the molten metal pot 2 is reduced. On the other hand, the upper end of the Stokes 12, that is, the mold 5
If a porous member that allows ventilation with the mold chamber 7 is provided at the contact part with the mold chamber 7, when the pressure inside the molten metal pot 2 is lowered, the gas flowing from the mold chamber 7 into the Stokes 12 will cause the Stokes 12 to The water level inside the tank will drop smoothly and quickly. Note that the porous member 28
As long as it is a refractory with air permeability and its porous part for ventilation is of a size that does not allow the flow of molten metal, it can be used in various ways.

〔Effect of the invention〕

As described in detail in each of the above embodiments, the present invention provides the following effects.

(1) According to the casting method and apparatus according to the first and second aspects of the present invention, when replacing the inside of the molten metal ladle and the mold chamber (temporary chamber) with vacuum-inert gas, the inside of the molten metal ladle and the inside of the chamber are mutually separated. By making these parts communicate with each other to equalize the pressure inside them, it is possible to reliably prevent the generation of a pressure cap between the inside of the bath water pot and the inside of the chamber, and to prevent the pressure from forming inside the temporary chamber or mold before completing the inert gas replacement. It is possible to effectively solve problems such as light droplets of molten metal, making it impossible to cast or producing defective products. In particular, since the above-mentioned effects can be achieved using equipment that is substantially the same as conventional equipment, there is no need for a particularly complicated control mechanism, and implementation can be easily carried out.

(2) According to the casting method according to the third aspect of the present invention, inert gas is charged into the molten metal pot and the mold chamber separately before they are assembled, and the upper part is opened when the mold is removed after casting. Inert gas is charged into the stokes, which contributes to improved efficiency by allowing the pouring operation to be performed immediately after changing the mold, and also prevents oxidation of the molten metal inside the stokes when changing the mold. It is possible to reliably prevent and reduce the generation of oxides, and also to easily remove them, thereby improving product quality and obtaining high quality products, that is, products with less oxide generation.

(3) According to the casting apparatus according to the fourth aspect of the present invention, a porous member is provided at the upper end portion of the Stokes to allow ventilation between the inside of the mold chamber and the inside of the Stokes, but prevent the flow of molten metal. The rise and fall of the surface immediately responds to the gas pressure in the molten metal pot, eliminating the time lag between the pressure adjustment operation and the height of the molten metal in the Stokes, improving the performance of the casting device, increasing efficiency, and improving the casting product. The quality can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view for explaining the conventional @ structure position diagram, Figs. 2 to 6 are for explaining the present invention in detail, and Fig. 2 shows the first embodiment. 3 is a sectional view showing the second embodiment, FIG. 4 is a sectional view showing the third embodiment, FIG. 5 is a sectional view showing the fourth embodiment, and FIG. 6 is a sectional view showing the fourth embodiment. 5 is a cross-sectional view showing Example 5. FIG. 1... Molten metal, 2... Molten metal pot, 3... Partition plate, 5...
- Mold, 6... Space in the molten metal pot, 7... Mold chamber, 8 and 8'. 9 and 9'...Valve, 10...Pump, 11...
・Gas cylinder, 12...Stokes, 15...Temporary chamber, 17.18...Pipeline, 19...Communication hole, 2
0... Opening/closing member, 21.24... Stopper, 25... Inert gas injection pipe, 28... Porous member. Agent Patent Attorney Akio Takahashi 3rd Ward Satoru

Claims (1)

[Scope of Claims] 1. The interior of the bath pot and the mold chamber installed above the molten metal pot are once evacuated, replaced with inert gas, and then the inside of the bath pot is pressurized. In the casting method in which bath water is supplied to the mold via a Stokes that communicates the molten metal with the mold, the inside of the molten metal pot and the inside of the mold chamber are connected to each other when the inside of the hot water pot and the mold chamber are vacuumed and replaced with inert gas. A casting method characterized by communicating and creating equal pressure. 2. The casting method according to claim 1, characterized in that the communication operation between the molten metal pot and the mold chamber is started at the initial stage of internal vacuuming of the molten metal pot and the mold chamber.- 3. The molten metal pot The communication operation between the mold chamber and the molten metal pot)
Claim 1, characterized in that the process is terminated when the inside of the mold chamber is brought to atmospheric pressure by an inert gas.
Casting method described in insects. 4. A molten metal pot that stores molten metal, an FC mold chamber provided on the molten metal pot via a horizontal partition plate, a mold accommodated in the mold chamber, and a molten metal supply that communicates between the mold and the molten metal pot. vacuum equipment that is connected to the molten metal pot or the mold chamber and evacuates the inside thereof, gas replacement equipment that replaces the inside of these with an inert gas, and the inside of the molten metal pot and the @ mold chamber. 1. A casting apparatus comprising: communication means for communicating pressure equalization; and pressure means for pressurizing the inside of the molten metal pot to apply pressure for supplying the molten metal into the mold. 5. The casting apparatus according to item 4, characterized in that the communication means comprises a through hole formed in the partition plate and an opening/closing member for opening and closing the through hole. 6. Place the mold and mold chamber on the molten metal pot containing the molten metal, and lighten them with an inert gas.
In the low-pressure casting method, in which the molten metal is poured into the mold through the Stokes by pressurizing the inside of the bath pot, and after casting, the mold is replaced and the above operation is repeated, inert gas is charged into the molten metal pot and the mold chamber. This casting method is characterized in that these are carried out individually before assembly, and that inert gas is charged into a Stokes with an open top when the die is removed after the piece is made. 7. Communication between a bathtub containing bath water, a mold chamber formed on the molten metal pot via a horizontal partition plate, a mold accommodated in the mold chamber circle, and the mold and the molten metal pot a Stokes for supplying the molten metal, a vacuum equipment connected to the molten metal pot and the mold chamber to make the insides of these walls solid, a gas replacement device to replace the insides of these with inert scum, and The pressurizing means applies pressure for supplying the molten metal into the mold and removes the pressurizing force in the molten metal pot after the molten metal solidifies in the mold, and the Stokes upper end portion is provided with pressure means for supplying the molten metal into the mold. A casting device characterized by being provided with a porous member that allows ventilation with the inside of the Stokes but blocks the flow of bath water.