JPH05177266A - Method and device for molding super plastic alloy sheet - Google Patents

Abstract

PURPOSE:To carry out the molding with a high efficiency regardless the amount of production by a simple device at a low cost. CONSTITUTION:A super plastic alloy sheet is formed by pressurizing with a pressure gas from a pressurizing room while evacuating a die receiving box by inserting the super plastic alloy sheet 7 between both boxes of a forming device 22 composed of the pressurizing room 25 having a pressure gas introducing opening 26 and whose lower surface is opened, a fixed box 23 formed by partitioning a vacuum room having a vacuum evacuating opening 28 and the die receiving box whose upper surface is opened, which has a vacuum evacuating hole 30 connected through the vacuum evacuating opening 28 and a vacuum evacuating opening 31 and which receives a permeable forming die 33, and heating the total forming device in the heating furnace 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal plate, and more particularly to a method for forming a superplastic alloy plate.

[0002]

2. Description of the Related Art Recently, zinc-based, aluminum-based, titanium-based alloys, that is, superplastic alloys, which undergo a drastic deformation of several hundred to several thousand percent due to a very low deformation stress at a predetermined temperature and are rapidly deformed. Was developed.

Conventionally, the superplastic alloy sheet has been formed by pneumatic forming as shown in FIG.

In FIG. 5, reference numeral 1 denotes an upper chamber in which the lower surface is fixedly opened with an upper clasp plate 2 and the molding die 5 is arranged with the molding surface facing the opening. 4 is a lower chamber in which an air jet plate 6 for fixing and opening 4 and ejecting pressurized air is provided, and the upper and lower chambers 1 and 3 are connected to each other through an opening to form a molding device.

In the forming apparatus as described above, first, as shown in FIG. 1 (a), a superplastic alloy plate 7 heated to a predetermined forming temperature is clamped by upper and lower clamps 2 and 4 which are pressurized by a hydraulic press or the like. While holding it between the upper and lower chambers 1 and 3.

Subsequently, as shown in FIG. 2B, compressed air is ejected from the air jet plate 6 of the lower chamber 3 so that the superplastic alloy plate 7 is brought into close contact with the cavity of the molding die 5 as shown by the arrow. Press to mold.

FIG. 6 shows a pneumatic molding method using a molding apparatus different from the one described above.

This apparatus has a fixed chamber 8 provided with a flange 9 on the periphery and an opening and a compressed air introduction port 10, and a flange 12 provided on the periphery with an opened upper surface and a vacuum exhaust port 13. The movable chamber 11 provided is connected to and formed through an opening.

A heating plate 16 provided with a plurality of ventilation holes 17 is fixed to the lower surface of the fixed chamber 8 of the molding apparatus, and an induction coil 15 is arranged opposite to the heating plate 16 via a coil conduit 14. A molding die 18 to which a die moving ram 19 is fixed is provided on the movable chamber 11 with a molding surface facing the opening, and a plurality of timbre pressing rams 20 are fixed to the lower surface.

In molding using the above-described molding apparatus, first, the movable chamber 11 is pressed against the fixed chamber 8 by the chamber pressing ram 20, and the superplastic alloy plate 7 and the heating plate 16 and the flange are joined together. It is sandwiched between 12 and held between both fixed and movable chambers 8 and 11.

Then, the induction coil 15 is energized to heat the heating plate 1.
After heating the superplastic alloy plate 7 to a predetermined forming temperature via 6, the compressed air having a predetermined pressure is introduced from the compressed air introduction port 10 to the fixed chamber 8 and the movable chamber 11 is evacuated via the vacuum exhaust port 13. After exhausting the gas, the mold moving ram 19 is actuated to move the molding mold 18 to the movable chamber 11.
Move to near the opening.

As a result, the superplastic alloy plate 7 is introduced into the fixed chamber 8 and is ejected from the ventilation holes 17 of the heating plate 16, and the molding die 18 is subjected to the pressure difference between the pressure of the compressed air and the vacuum degree of the movable chamber 11. And is pressed against the molding surface of.

[0013]

However, according to the conventional pneumatic forming method, first, an expensive clamp mechanism utilizing hydraulic pressure or pneumatic pressure for holding the superplastic alloy plate to be mounted and the superplastic alloy plate are used. In order to heat to a predetermined temperature, an expensive heating device such as an induction heating device is required.

Therefore, in the conventional molding method, the apparatus becomes expensive, and when the production scale is small, the depreciation cost of the apparatus becomes a large burden and the cost of the product becomes very high.

It is an object of the present invention to solve the above-mentioned drawbacks of the prior art and to provide a method for forming a superplastic alloy which can be formed by a simple apparatus and is well suited for small-scale production.

[0016]

That is, according to the present invention, a pressurizing chamber having an opening on the lower surface and having a pressurized gas introduction port and a vacuum chamber having a vacuum exhaust port communicating with the lower surface on the outer periphery of the pressurizing chamber are partitioned. A mold accommodating box having a formed fixed box, an upper surface vacuum exhaust hole communicating with a vacuum exhaust port of the fixed box and a vacuum exhaust port connected to a vacuum exhaust pipe, and accommodating a breathable mold. And a superplastic alloy sheet forming device, wherein the forming device is connected to each other through an opening, and the forming device is preferably disposed in a heating furnace for heating the entire device, and , The superplastic alloy plate is held by a vacuum suction force between both the fixed and mold accommodating boxes, and it is preferable that the mold accommodating box is decompressed while the pressurizing chamber of the fixed box is used for molding. Superplastic alloy characterized by It is a method of molding.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 21 is a heating furnace for accommodating the molding apparatus 22 as a whole, and 23 is a fixed box. The fixed box 23 has a pressurizing chamber 24 whose lower surface is opened and the pressurizing chamber 24. It is partitioned into a vacuum chamber 25 that surrounds the outside.

The pressurizing chamber 24 is provided with a pressurizing gas inlet 26 to which a pressurizing gas supply pipe 27 is connected, and the left and right end surfaces of the vacuum chamber 25 are provided with vacuum exhaust ports 28, 28 communicating with the lower surface. ing.

Reference numeral 29 designates a mold accommodating box having an open top surface. In this mold accommodating box 29, a vacuum exhaust hole is formed at the edge portion of the upper surface, and a joint portion protruding from a vacuum exhaust port 28 of the fixed box 23 is projected. A vacuum exhaust port 31 to which a vacuum exhaust pipe 32 is connected is provided on the side wall.

Further, the mold accommodating box 29 is attached with a bolt 36 because it is convenient for accommodating a mold for molding when the bottom plate 35 is detachable.

Reference numeral 33 denotes a molding die as shown in FIG. 3, which is a copy of the shape of a product molded from a material having air permeability and heat resistance such as gypsum, cement, and a ceramic sintered body, and 34 is a molding die. This is a support particle layer for backing up the molding die 33.
In order to store the mold in the box, first, the bottom plate 35 is removed and the mold containing box 29 is placed upside down.

Next, the molding die 33 is put into the die housing box 29 with the molding surface side of the cavity or the core facing downward, and then, for example, a diameter of 5 mm is placed in the gap between the die housing box 29 and the molding die 33. After the fine metal particles such as copper are densely packed as the support particle layer 34 to form a breathable backup layer, the bottom plate 35 is attached with bolts 36.

After the mold accommodating box 29 accommodating the molding mold 33 is accommodated in the heating furnace as described above, the superplastic alloy plate 7 is fitted on the upper surface of the positioning hole in the joint portion where the vacuum exhaust holes 30 and 30 project. Then, the fixed box 23 is placed thereon while fitting the vacuum exhaust ports 28, 28 into the joint portions of the vacuum exhaust holes 30, 30 of the mold housing box 29.

After the setting of the forming device 22 is completed as described above, the heating of the heating furnace 21 causes A7475 (Al-5.7Zn-2.3Mg-) as a superplastic alloy plate.
When 1.5 Cu) is used, the whole apparatus is heated to 515 ° C. and the forming temperature corresponding to the superplastic alloy to be formed.

After the molding apparatus as a whole reaches a predetermined molding temperature, the inside of the mold housing box 29 is evacuated through the vacuum exhaust port 31 by the operation of a vacuum pump (not shown).

Due to this evacuation, the molding die 33 and the support particle layer 34 are breathable, so that the die housing box 29.
The inside is uniformly depressurized, and the vacuum chamber 25 of the fixed box 23 in which the vacuum exhaust ports 28 and 28 are connected to the vacuum exhaust holes 30 and 30 is also depressurized.

Therefore, the fixed box 23 is sucked toward the mold housing box 29, and the superplastic alloy plate 7 is firmly held between the fixed and mold housing boxes 23 and 29.

In this state, further evacuation is continued, and 310
The pressure in the mold housing box 29, which was about Torr, was reduced to about 10 Torr, and the fixed box 2
A pressurized gas such as nitrogen gas having a pressure of about 1 kg / cm 2 is introduced into the pressurized chamber 24 from the pressurized gas supply pipe 27 of No. 3 through the pressurized gas inlet 26.

When the state in which the vacuum suction force and the pressurizing force of the pressurized gas are simultaneously applied to the superplastic alloy plate 7 in this manner is about 10 minutes, the superplastic alloy plate 7 is, as shown in FIG. Deforms following the molding surface of the molding die 33 to obtain a molded body 37.

[0031]

The structure and operation of the present invention are as described above. First, since the forming apparatus is compact, a special superplastic alloy plate for forming the entire forming apparatus in a heating furnace and heating the entire apparatus is special. It can be easily heated to the molding temperature without using an apparatus.

Further, since the superplastic alloy plate is held by using the vacuum suction force, the holding mechanism is simple and when the holding jig is used even when the forming apparatus is put in the heating furnace and heated. The retention does not become incomplete due to the effect of thermal expansion.

As an example in which the superplastic alloy plate is held in the forming apparatus by using the holding jig, the superplastic alloy plate 7 is connected to the pressurizing gas supply pipe 29 on the upper surface of the mold housing box 29 in FIG. The molding apparatus is shown in which the holding plate 38 provided with the pressurized gas introduction port 39 is used to attach the bolts 40 and 40 while pressing the holding plate 38.

When this molding apparatus is placed in a heating furnace and heated to the molding temperature, the bolts 40, 40 are loosened due to thermal expansion, and the superplastic alloy plate 7 cannot be held in close contact. Pressurized gas leaks and sufficient pressurization cannot be performed.

On the other hand, in the case of the present invention, first, when the mold housing box 29 is made of SS material, this thermal expansion coefficient is smaller than the thermal expansion coefficient of the copper support particle layer 34. The molding die 33 is supported by the support particle layer 34.
The force of pressing against the edge of the upper surface of the mold accommodating box 29 while supporting it becomes rather strong.

Further, the superplastic alloy plate 7 is held by a vacuum suction force of the fixed box 23 to the mold housing box 29, which is generated by evacuation of the vacuum chamber 25 of the mold housing box 29 and the fixed box 23 communicating therewith. The heating of the molding device 22 by the heating furnace 21 does not affect the holding force at all.

As described above, in the present invention, even when the molding apparatus is heated to a relatively high molding temperature, the molding die 33 is held tightly in the die housing box 29 with the molding surface facing the opening of the upper surface. At the same time, since the superplastic alloy plate 7 is also firmly held on the upper surface of the mold housing box 29, the molding operation can be smoothly performed.

In the molding, the mold housing box 29 is used.
Since it is decompressed, a large pressing force can be applied to the superplastic alloy without increasing the pressure of the pressurized gas to a superplastic alloy plate of any material or thickness, which is good for the forming surface shape of the forming die. Highly accurate molding can be easily performed.

As described above, the present invention provides a simple and low-cost forming apparatus for forming a superplastic alloy sheet, and a forming method for smoothly obtaining an extremely high quality product using this forming apparatus. Therefore, the superplastic alloy sheet can be easily formed at a low cost regardless of the forming amount.

[Brief description of drawings]

FIG. 1 Example

FIG. 2 shows an embodiment,

FIG. 3 is a perspective view of a molding die,

FIG. 4 is a conventional example,

FIG. 5 Conventional example,

FIG. 6 shows a conventional example.

[Explanation of symbols]

 7 Superplastic alloy plate 21 Heating furnace 22 Forming device 23 Fixed box 24 Vacuum chamber 25 Vacuum chamber 26 Pressurized gas inlet 27 Pressurized gas supply pipe 28 Vacuum exhaust port 29 Type accommodation box 30 Vacuum exhaust hole 31 Vacuum exhaust port 32 Vacuum Exhaust pipe 33 Mold 34 Support particle layer

Claims (4)

[Claims] 1. A fixed box in which a pressurization chamber having a bottom surface opened and having a pressurization gas introduction port and a vacuum chamber having a vacuum exhaust port communicating with the bottom surface of the outer periphery of the pressurization chamber are defined and formed. A mold accommodating box, which has an evacuation hole on the upper surface that is open and communicates with the evacuation port of the fixed box and a evacuation port to which a evacuation pipe is connected, and that accommodates a breathable mold, is connected through the openings of each other A device for forming a superplastic alloy sheet, which is formed by 2. The superplastic alloy sheet forming apparatus according to claim 1, wherein the forming apparatus is provided in a heating furnace for heating the apparatus as a whole. 3. A method for forming a superplastic alloy plate, which comprises holding the superplastic alloy plate between the fixed and mold accommodating boxes by a vacuum suction force. 4. A method of forming a superplastic alloy sheet, comprising forming the superplastic alloy sheet while reducing the pressure inside the mold-holding box and pressurizing the pressure inside the pressurizing chamber of the fixed box.