JPH05318077A - Vacuum vertical injection casting method and device therefor - Google Patents

Abstract

PURPOSE:To provide the vacuum vertical injection casting method which obviates the generation of blowholes and the inclusion of oxides even with an active metal and can cast the metal at a high speed in an extremely clean form. CONSTITUTION:A metallic ingot is charged into an injection sleeve 17 and after the atmosphere enclosing the injection sleeve 17 is maintained in a vacuum state, the metal is melted while the vacuum state is maintained; thereafter, the injection sleeve 17 is connected to a sprue (c) of metallic molds (A) and the molten metal (Y) in the injection sleeve 17 is injected and packed into the metallic molds (A) held in the vacuum state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vertical injection casting method and apparatus. More specifically, it relates to a vacuum vertical injection casting method and apparatus capable of high-speed injection casting in a high vacuum state while keeping the active molten metal in a clean state.

[0002]

2. Description of the Related Art For example, when an active alloy, such as an alloy containing a rare earth element or an amorphous alloy, is melted and cast, the atmosphere is atmospheric so that it is oxidized when pouring or filling the mold. However, there are various problems such as a decrease in mechanical strength and a decrease in amorphous forming function.

As a casting method for such an active metal, a die casting method, which has a high casting speed, has been adopted because rapid casting and rapid cooling are indispensable. There was a problem in that gas was trapped inside the mold and the mold, causing cavities and frequent defective products. Therefore, in order to solve the above problems, a laminar flow die casting method and a vacuum die casting method have been developed.
We have not been able to solve all of the problems that occur with respect to casting of active metals.

That is, in the above-mentioned laminar flow die casting method, the casting time is long and the molten metal is slowly cast into the mold. In that case, the mold temperature is, for example, 300.degree.
It is kept at a high temperature of 400 ° C to prevent solidification of the molten metal during casting. As a result, although the occurrence of cavities is reduced, the solidification time of the cast product after the casting is completed becomes coarse and the crystal grains of the cast product become coarse, and the problem that the mechanical strength decreases,
There is also a problem that the working cycle becomes long and working efficiency deteriorates because the solidification time becomes long, and there is also a problem that the mold life is shortened because the mold side is exposed to high temperature for a long time.

Further, in the vacuum die casting method, the pressure inside the mold is as low as 50 to 250 Torr and the degree of vacuum is low, so that only a pressure reducing effect can be expected, and the conventional vacuum die casting method is very difficult to cast, and the casting method is very difficult. It was also difficult to prevent the formation of nests due to the entrainment of gas. Furthermore, there is an inflow into the molten metal of the atmosphere from the clearance between the plunger and the injection sleeve,
The problem of containing gas in the molten metal could not be solved.

In addition, there is a method of pouring the molten metal into the injection sleeve with a ladle, but it is not practical as a casting method of the active metal because air is entrained during the pouring and oxidation is caused to cause defects in the product. It was

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and the object of the present invention is to achieve high-speed operation in an extremely clean form with no generation of cavities or entrapment of oxides even with active metal. It is to provide a vacuum vertical injection casting method and apparatus capable of casting.

[0008]

According to the vacuum vertical injection casting method of claim 1, "a metal block (K) is put into an injection sleeve (17) and an atmosphere surrounding the injection sleeve (17) is brought into a vacuum state. After that, the molten metal (Y) in the injection sleeve (17) is vacuumed by connecting the injection sleeve (17) to the gate (c) of the mold (A) while melting while maintaining the vacuum state. Mold held in the state (A)
It is injection-filled inside ”. As a result, the metal (Y) to be cast will be processed in a vacuum until the casting is completed, resulting in the generation of oxides during melting and casting and the generation of cavities due to gas entrainment during casting. It is possible to obtain extremely high quality cast products without such problems. Moreover, since casting is performed by injection filling, high-speed casting and rapid cooling can be performed, so that casting of alloys containing rare earth elements and active metals such as amorphous metals can be sufficiently dealt with.

A second aspect is characterized in that, in addition to the first aspect, "the bubbling is performed by supplying an inert gas (F) into the molten metal while maintaining a vacuum state". As a result, impurities and storage gas in the molten metal (Y) float with bubbles of the inert gas, and the cleanliness of the molten metal (Y) can be increased.

A vacuum vertical injection casting apparatus (M) according to claim 3 is for carrying out the method, and comprises a "casting die (A),"
Injection cylinder (1 for injection and filling the mold (A) with molten metal (Y)
7) and the injection sleeve (17) that is attached to the injection cylinder (17), and the plunger (18) at the tip of the cylinder rod moves inside and holds the molten metal (Y) injected into the mold (A). )When,
Move the injection cylinder (13) to bring the injection sleeve (17) into contact with the gate (c) of the mold when injecting and filling the molten metal (Y), and when not injecting, the injection sleeve (17) is the mold (A). Enclose the periphery of the injection cylinder (10) and the moving cylinder (10) that is separated from the
Expansion and contraction sleeve chamber for vacuum that communicates with the cavity (a) of the casting mold (A) in the closed state to make the cavity (a) and the surrounding space of the injection sleeve (17) a closed space (C) (9)
And an evacuation means (E) for bringing the closed space (C) into a vacuum state, and a heating and melting means (H) for heating and melting the metal lump (K) charged in the injection sleeve (17). ] Characterized by that.
Thereby, the metal ingot (K) is processed at high speed in a vacuum from melting to completion of casting, and an extremely high quality cast product can be obtained even with an alloy containing a rare earth element or an active metal such as an amorphous metal.

A fourth aspect of the present invention is the same as the third aspect, wherein "a gas passage gap is provided between the plunger (18) and the injection sleeve (17).
(S) is formed, and the space (17a) of the injection sleeve (17) opposite to the molten metal (Y) side is filled with the inert gas (F) through the plunger (18). To do. As a result, the inert gas (F) is supplied from the gas passage gap (S) into the molten metal (Y), and effective bubbling is performed.

[0013]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of a vertical injection casting apparatus (M) used in the present invention, in which a plurality of tie bars (22) are erected in parallel,
The top and bottom ends of the tie bar (22) are fixed by a top platen (2) and a bottom platen (6), respectively, and the bottom platen (6) is supported by a frame (20).
The number of tie bars (22) is four in this embodiment, but is not limited to this and may be three or two. In this case, the tie bars (22) are erected parallel to the four corners of the bottom platen (6), and their upper ends are fixed to the top platen (2). The bottom platen (6) has a lower surface on which a moving cylinder (10) is mounted.
(a) is attached to the injection cylinder (13) to raise and lower the entire injection cylinder (13). Transfer Cylinder (10)
The number is two in this embodiment, but it may be two or more, or one by providing an appropriate guide.

A movable platen (3) is arranged on the tie bar (22) so as to be able to move up and down, and the movable platen (3) is mounted on the top platen (2) by a direct pressure type hydraulic cylinder (1) for clamping. The movable platen (3) can be moved up and down. A movable mold (4) is mounted on the lower surface of the movable platen (3) so that it moves up and down together with the movable platen (3).

A fixed mold (5) is mounted on the bottom platen (6), and a cast product is formed integrally with the movable mold (4) mounted on the lower surface of the movable platen (3). .. And
A runner (c) communicating with a cavity (15) formed on a parting surface of the fixed mold (5) and the movable mold (4) is formed in the fixed mold (5). (14) is an extrusion cylinder, which is a movable platen.
It is installed in (3) and operates the eject pin (14a) installed in the movable mold (4).

As described above, the injection cylinder (13) is arranged below the bottom platen (6) so that it can be moved up and down. The injection cylinder (13) has a cylinder body (13b),
It is composed of a rod chamber (12) and a cylinder rod (13a). The rod chamber (12) is
It is attached to the upper surface of a), and the injection sleeve (17) is further attached to the opening of the upper surface. Cylinder body (1
The cylinder rod (13a) protruding from 3b) is inserted into the injection sleeve (17) through the rod chamber (12), and the plunger that is the tip of the cylinder rod (13a).
The (18) slides in the injection sleeve (17), and molten metal (Y) cannot pass between the plunger (18) and the injection sleeve (17), but gas flow does not occur. The gas passage gap (S) is formed as is possible.

The rod chamber (12) has an exhaust / gas filling port
(11) is provided, and exhaust means (E) is attached to this exhaust / gas charging port (11). {If necessary, an inert gas supply means (FK) is additionally provided, and the exhaust means (E) and the inert gas supply means (FK) constitute a replacement means. The exhaust means (E) is, for example, an exhaust pump, and the inert gas supply means (FK) is, for example, an argon gas cylinder, which are all known. or,
Inert gases are also known, for example argon. A thermocouple (21) reaching almost the tip of the plunger (18) is arranged in the cylinder rod (13a) so that the temperature of the molten metal (Y) in contact with the plunger (18) can be measured.
Reference numeral (21a) is a lead wire connected to the thermocouple (21) and is drawn out through the rod chamber (12) to be connected to an external temperature measuring device (not shown).

The injection sleeve (17) comprises a rod chamber (12).
Sleeve fixing part (19) fixed to match the upper opening of the
And the cylindrical part (17a) mounted on the sleeve fixing part (19)
It consists of and. A fitting protrusion is projected from the upper end of the sleeve fixing part (19) and is fitted into a fitting recess formed in the lower end of the cylindrical part (17a), and the inner surface of both (17a) and (19) Are flush with each other so that the plunger (18) can smoothly slide on the inner surface. The injection sleeve (17) is made of ceramics in this embodiment.

(9) is a vacuum telescopic sleeve chamber that surrounds the periphery of the injection sleeve (17) and is divided into two parts, an upper sleeve chamber (9a) and a bottom platen.
The lower sleeve chamber (9
b) is mounted on the upper surface of the rod chamber (12). The ends of the upper and lower sleeve chambers (9a) and (9b) are fitted to each other, and a heat resistant O-ring (8) is attached to the sliding contact surface, and the vacuum expanding and contracting sleeve chamber (9) is attached from the sliding contact surface. Outside air does not flow into the inside.

Reference numeral (H) is a heating and melting means for heating and melting the metal block (K) charged in the injection sleeve (17). Of course, this is not restrictive, but induction heating is used in this embodiment. Therefore, (16) is an induction heating coil. Incidentally, injection sleeve
(17) The heat insulating material for keeping the molten metal (Y) inside is omitted.

The metal to be melted in this apparatus (M) is not particularly specified, but it is most suitable for melting and casting an active alloy, for example, an alloy containing a rare earth element or an amorphous alloy.

Next, the operation of this apparatus will be described. (Material Input) The moving cylinder (10) is operated to lower the injection cylinder (13), separate the lower sleeve chamber (9b) from the upper sleeve chamber (9a), and expose the injection sleeve (17). In this state, a clean metal block (K) is charged into the injection sleeve (17) automatically or manually. The metal ingot (K) is adjusted in advance so as to have a predetermined composition.

(Degassing in sleeve chamber) The moving cylinder (10) is operated to raise the injection cylinder (13) to the interruption, and the lower sleeve chamber (9b) is opened at the lower opening of the upper sleeve chamber (9a). Insert the top opening. During this period, the mold clamping cylinder (1) is operated to lower the movable mold (4) and press it against the fixed mold (5) to complete the mold clamping.
As a result, the cavity (1) of the casting mold (A) in the closed state is
5) and the surrounding space communicating with this and surrounding the periphery of the injection sleeve (17) become a closed space (C) isolated from the outside world.
At this time, the exhaust means (E) exhausts the closed space (C) and the rod chamber (12) to a high vacuum of, for example, 1 × 10 ⁻³ Torr. Rod chamber (12) and closed space
Since (C) is slightly connected with the gas passage gap (S), even if only the closed space (C) is evacuated, a high vacuum cannot be achieved unless the rod chamber (12) side is evacuated. As a method of obtaining a high vacuum, for example, a tank having a large capacity
(Not shown) is evacuated to a predetermined vacuum degree in advance, and this tank is provided with an exhaust / gas charging port (11) of the rod chamber (12) and an exhaust port (7) formed in the bottom platen (6). It is evacuated to a predetermined degree of vacuum by a known means such as a method of connecting and a method of evacuating directly by a vacuum pump (not shown).

(Metal Melting) When the closed space (C) and the inside of the rod chamber (12) reach a predetermined vacuum degree, the induction heating coil (1)
The metal mass (K) in the injection sleeve (17) is induction-heated and quickly melted by 6). The temperature of the metal (K) is measured by a thermocouple (21) provided in the plunger (18), and heated to the target temperature. In the case described above, bubbling is performed only in vacuum melting, but when bubbling is performed, the following is performed. That is, when the metal (K) is dissolved, the exhaust gas (7) of the bottom platen (6) is still exhausted, while an inert gas such as argon gas is exhausted from the exhaust / gas charging port (11) of the rod chamber (12). (F) is supplied, for example, from 5 liters per minute to 100 liters per minute. As a result, the inert gas (F) flows from the bottom through the gas passage gap (S) to the molten metal.
Bubbles flow into the (Y), rise while bubbling the molten metal (Y), and effectively degas the molten metal (Y). The released gas and the inert gas (F) are the bottom platen (6).
Since it was sucked from the exhaust port (7) of, the high vacuum state was still maintained during the melting work. As a result, the amount of residual gas in the molten metal (Y) was 3 in the conventional case per 100 g of aluminum.
What was ~ 10cc was able to be reduced to 0.1cc.

(Ejection) When the molten metal (Y) reaches a predetermined temperature (when bubbling is performed, the bubbling work is completed and reaches a predetermined temperature), the induction heating is turned off, and at the same time. Alternatively, subsequently, the moving cylinder (10) is re-activated, the injection cylinder (13) is lifted together with the injection sleeve (17), and the upper end of the injection sleeve (17) is used as the gate (c) of the fixed mold (5). Get connected quickly. Then, by operating the injection cylinder (13), the molten metal (Y) in the injection sleeve (17)
Is filled in the mold cavity (15) by high-speed injection.

(Mold opening / extrusion) Injection into the cavity (15)
The molten metal (Y) filled is deprived of heat by the mold (A), rapidly cooled and solidified, and after a short chill time, the mold clamping cylinder.
(1) is reversely operated, the movable platen (3) and the movable mold (4) are raised, and the mold is opened. The solidified casting is released from the fixed mold (5) together with the movable mold (4), and when the movable mold (4) stops at the top dead center, the extrusion cylinder (14) operates and the eject pin (14a). To eject the cast product from the movable mold (4) and take it out of the apparatus. When the removal of the cast product is completed, the mold clamping cylinder (1) operates again and the movable mold
The movable platen (3) descends together with (4) and closes the mold. After that, the casting operation is performed by repeating the above operation.

On the other hand, the plunger (18) of the injection cylinder (13)
In order to ensure that the cast product is released from the fixed mold (5), it rises to the top dead center with the riser, then descends and returns to the bottom dead center, and then the moving cylinder. Reverse the operation of (10), lower the injection cylinder (13) together with the injection sleeve (17) to the bottom dead center, and fix the upper end of the injection sleeve (17) to the fixed mold (5).
Prepared for the next casting work by separating from the sprue (c).

[0028]

[Effects of the Invention] By the hot water supply method according to the first aspect of the present invention or the apparatus according to the third aspect, all the steps from the melting of the metal block to the injection of the mold are performed in a vacuum state, whereby the melting and casting There is an advantage that an extremely high quality cast product can be obtained without the generation of oxides therein and the formation of cavities due to gas entrainment during casting. Moreover, since the casting is performed by high-speed injection filling, it is possible to perform high-speed casting and rapid cooling, and there is an advantage that casting of an alloy containing a rare earth element or an active metal such as an amorphous metal can be sufficiently coped with. Since there is no gas entrapment due to high-speed injection filling, the mold temperature can be lowered and the mold life can be extended. Furthermore, by quenching, the crystal grains of the cast product could be made finer and amorphous.

Further, bubbling with an inert gas in a vacuum state by the method as claimed in claim 2 or the apparatus as claimed in claim 4 can effectively remove impurities in the molten metal and degas. There is an advantage that the cleanliness of the molten metal can be increased.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of one embodiment of the entire vacuum vertical injection casting apparatus of the present invention.

FIG. 2 is a partial schematic cross-sectional view showing a state when a raw material metal is charged in the present invention.

FIG. 3 is a partial schematic cross-sectional view showing a state during melting of a raw material metal in the present invention.

FIG. 4 is a partial schematic cross-sectional view showing a state immediately before injection in the present invention.

[Explanation of symbols]

 (A) ... Mold (K) ... Metal block (Y) ... Molten metal (F) ... Inert gas (M) ... Vacuum vertical injection casting machine (C) ... Closed space (E) ... Exhaust means (H) ... Heating and melting means (S) ... Gas passage gap (13) ... Injection cylinder (15) ... Cavity (17) ... Injection sleeve (18) ... Plunger (C) ... Gate

Claims (4)

[Claims] 1. A metal lump is charged into an injection sleeve,
After the atmosphere surrounding the injection sleeve was made into a vacuum state, it was melted while maintaining the vacuum state, and then the injection sleeve was connected to the gate of the mold to hold the molten metal in the injection sleeve in a vacuum state. A vacuum vertical injection casting method characterized by injection filling in a mold. 2. The vacuum vertical injection casting method according to claim 1, wherein an inert gas is supplied into the molten metal while bubbling is performed while maintaining a vacuum state. 3. A casting mold, an injection cylinder for injecting and filling the mold with molten metal, and a molten metal held in the injection cylinder by a plunger at the tip of the cylinder rod moving inside the mold. A moving cylinder that moves the injection sleeve and the injection cylinder that are injected and filled into the inside so that the injection sleeve contacts the gate of the mold when the molten metal is injected and filled, and the injection sleeve is separated from the mold when not injecting the molten metal. And a vacuum expansion and contraction sleeve chamber for communicating the cavity of the casting mold in a closed state to make the cavity and the surrounding space of the injection sleeve a closed space, and the closed space in a vacuum state. The vacuum vertical injection casting apparatus is characterized in that it is constituted by an exhausting means for heating and a heating and melting means for heating and melting the metal ingot injected into the injection sleeve. 4. A gas passage gap is formed between the plunger and the injection sleeve, and the space of the injection sleeve opposite to the molten metal side is filled with an inert gas through the plunger. 5. The vacuum vertical injection casting apparatus according to the third section.