JPH0284218A - Forming method for superplastic metallic plate - Google Patents

Abstract

PURPOSE:To function a bent peripheral edge part as a sealed member by forming the bent peripheral edge part to the peripheral edge part of a metallic plate to be worked to make a sealed member, forming a sealed cabin on one side and changing the pressure of the sealed cabin by heating to adhere the metallic plate to the formed surface. CONSTITUTION:The bent peripheral edge part 40 is formed on the peripheral part of the metal 4 to be worked. A sealing cover 2 is lowered to hold the bent peripheral edge part 40 by a die side holding surface 11 and a cover side holding surface 21. A plate to be worked is heated by a heater up to a prescribed temperature through a forming die 1 and a sealing cover 2. Inert gas having a prescribed pressure is supplied into a sealed cabin 5 through a supply pipe 3 to perform a blow forming. The metal 4 to be worked is worked plastically along the formed surface 10 of a forming die 1 to make a formed part 40. Since the bent peripheral edge part of the metallic plate to be worked is made to be held, the bent peripheral edge part is functioned as a sealed member, sealing property is improved, the rigidity of the peripheral edge part is raised and the deformation of the formed part can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a superplastic metal plate, and particularly to a sealing technique for an airtight chamber defined between a sealing lid and a metal plate to be processed.

(Prior Art) Conventionally, as a technique for sealing an airtight chamber in a method for forming a superplastic metal plate, a technique as described in, for example, Japanese Patent Application Laid-Open No. 61-238423 is known.

This conventional sealing technique, as shown in FIG.
During the clamping process in which the peripheral edge 301 of the metal plate 300 to be processed is clamped between the mold side clamping surface 101 of the seal lid 200 and the lid side clamping surface 201 of the seal lid 200, the lid side clamping surface 201 and the metal plate 300 to be processed are A thin plate sealing member 40 is placed between the peripheral edge 30J of
0 was set.

In addition, as shown in FIG. 7, the lid side clamping surface 20
A protrusion 202 is formed on the protrusion 2. A groove 102 that fits into the protrusion 2.2 is formed on the mold side clamping surface 101, and a seal is formed on the peripheral edge 301 of the metal plate 300 to be processed during the clamping process. A device in which the bead 302 is processed is known.

(Problems to be Solved by the Invention) However, the above-mentioned conventional technology has the following problems.

In the former case, a thin plate seal member 400 manufactured in a process separate from the clamping process and the forming process is placed between the seal lid 200 and the peripheral edge 301 of the metal plate 300 to be processed, which will serve as the clamping part, each time the clamping process is performed. This requires a lot of effort and time, which reduces work efficiency.

In the case of restoration, the mold 100 and the clamping surfaces 101, 201 of the seal 200 are deformed due to the influence of heat in a high temperature range, the sealing surface is deformed, the sealing surface pressure becomes uneven, and the sealing performance is impaired. , normal pressurization is difficult.

The present invention was made in order to solve the conventional problems as described above, and improves the sealing performance between the lid-side clamping surface of the seal lid and the peripheral edge of the metal plate to be processed. The purpose is to make it easier to take out the molded product while reducing deformation of the molded product due to the metal plate to be processed.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the method for forming a superplastic metal plate of the present invention, a mold-side clamping surface formed on the periphery of a mold, and a mold-side clamping surface formed on the mold-side clamping surface. A clamping step is performed in which the peripheral edge of the metal plate to be processed is held between the opposing lid-side clamping surfaces formed on the peripheral edge of the sealing lid to form an airtight chamber on at least one side of the metal plate to be processed. Then, while the metal plate to be processed is heated to a predetermined temperature at which it becomes superplastic, the air pressure in the airtight chamber is changed, and the metal plate to be processed is brought into close contact with the molding surface of the mold to undergo plastic processing. In the method for forming a superplastic metal plate that includes a forming step, before the clamping step, a bent peripheral portion is formed on the peripheral edge of the metal plate to be processed by bending or curving inward toward the airtight chamber. In the clamping step,
The bent peripheral edge portion is held between both holding surfaces.

Here, the metal plate 4 to be processed is made of a so-called superplastic alloy, and exhibits several hundred percent elongation at around 500°C. Omm, Al257% Zn
-2,4% Mg-1,6% Cu alloy is used.

(Function) As described above, in the present invention, before the clamping step, a bent or curved peripheral edge portion that is bent or curved inward toward the airtight chamber is formed on the peripheral edge portion of the metal plate to be processed in advance. The bent peripheral edge portion is held between the mold-side holding surface of the mold and the lid-side holding surface of the seal lid.

Therefore, when the bent peripheral edge is held between the two clamping surfaces in this manner, the bent peripheral edge is deformed so as to overlap with the main body of the metal plate to be processed. During this deformation, between the two clamping surfaces and the bent peripheral edge, the bent peripheral edge deforms from the point where the clamping pressure is strongly applied.In other words, this clamping pressure becomes the sealing pressure. This difference in sealing pressure causes a difference in the amount of deformation, and the sealing pressure is made uniform based on this deformation.

At the same time, the bent peripheral edge functions as a sealing member between both clamping surfaces, and even if the lid-side clamping surface is thermally deformed in a high crystal region, for example, the bent peripheral edge will not fit into the lid-side clamping surface. can.

Furthermore, after the forming process is completed, the bending periphery is polymerized to form a double-thickness structure, which increases the rigidity of the periphery of the metal plate to be processed, reducing deformation of the molded product. This makes it easier to take out items.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a sectional view showing a molding apparatus used in the molding method according to one embodiment of the present invention.

In the figure, reference numeral 1 denotes a mold, and a molding surface IO is formed in a concave shape on the upper surface, and a mold-side clamping surface 11 is formed on the periphery of the upper surface.

A seal lid 2 is provided above the mold l so as to be movable up and down, and a lid-side clamping surface 21 is formed on the periphery of the lower surface of the seal lid 2, facing the mold-side clamping surface 11. A recess 20 for an airtight chamber 5 is formed inside the lid-side clamping surface 21.

Further, a gas supply pipe 3 is attached to the seal lid 2 to extend through the seal M2 and reach the inside of the recess 20.

Incidentally, a heater (not shown) is attached to the mold l and the seal lid 2.

In FIG. 2, the peripheral edge of the metal plate 4 is held between the mold l and the seal lid 2, and the metal plate 4 is made of a so-called superplastic alloy. 5
It exhibits extensibility of several hundred percent at around 00°C, for example, when the plate pressure is 1. omm, A9. −5.7% Zn −
A 2,4% Mg-1,6% Cu alloy is used.

Next, the forming method of this embodiment will be explained with reference to the process explanatory diagram of FIG. 1 and the perspective view of a cross section showing a metal plate to be processed as shown in FIG. 3.

(a) Pre-process First, as shown in FIG. 3, the peripheral edge of the metal plate 4 to be processed is bent inward so as to face upward and toward the airtight chamber 5. 40 is formed. Note that this bent peripheral edge portion may be a bent peripheral edge portion 240 that is curved into a curled shape, as shown in FIG. Incidentally, the peripheral edge of this limit portion may be wrinkled or may be formed in two layers.

(b) Holding process Next, as shown in FIG. 1(a), the metal plate 4 to be processed is
Place it on the mold-side clamping surface 11 of the mold l.

Then, as shown in FIG. 1(b), the seal lid 2 is lowered and the bent peripheral edge 40 is clamped between the mold-side clamping surface 11 of the mold l and the lid-side clamping surface 21 of the seal lid 2. .

In this way, both clamping surfaces 11.21 bend the peripheral edge 40.
When it is pinched, this bent peripheral edge part 40 is deformed so as to be folded back into a superposed state as shown in FIG. The amount of deformation of 40 is such that the surface pressure between both clamping surfaces 11.21 and the bent peripheral edge 40 is equalized, thereby equalizing the sealing pressure between the three [11, 21, 40].

Further, this bent peripheral edge portion 40 functions as a sealing member between the metal plate 4 to be processed and the lid-side clamping surface 21.

In this state, an airtight chamber 5 is defined between the metal plate 4 to be processed and the seal lid 2 at the position of the recess 20.

(c) Forming process Next, the metal plate 4 to be processed is heated to about 500° C. via the forming mold 1 and the sealing lid 2 using a heater (not shown).

In this state, in the airtight chamber 5, Ar, Nz at about 10 atm.
The so-called blow molding is performed by supplying so-called inert gas such as through the gas supply pipe 3, whereby the metal plate 4 to be processed is placed in the mold 1 as shown in FIG. 1(C).
is plastically worked along the molding surface 10 of. That is, the metal plate 4 to be processed becomes a molded product 4a.

At this time, as described above, the bent peripheral edge part 40 of the metal plate 4 to be processed is held between both the clamping surfaces 11.21, and this bent peripheral edge part 40 functions as a sealing member. Even if the side clamping surfaces 21 are thermally deformed, the clamping pressure from both clamping surfaces 11 and 21 deforms the bending peripheral edge 40 to accommodate the deformation and ensures sealing, so that the inert gas from the airtight chamber 5 is Gas leakage can be prevented.

After the above-mentioned molding process is completed, the molded product 4a is removed from the mold l, but at this time, the periphery of the molded product 4a is
As shown in FIG. 4, since the bent peripheral edge 40 is in a superposed state and has a double thickness structure, the rigidity of the peripheral edge is high, and therefore the molded product 4a is less deformed and the molded product 4a is less deformed. The work of taking out the product 4a from the mold l becomes easier.

(Effects of the Invention) As explained above, in the method for forming superplastic metal of the present invention, a bent peripheral edge is formed on the peripheral edge of a metal plate to be processed, and then the bent peripheral edge is held. Due to this structure, the sealing pressure can be made uniform based on the deformation of this bent peripheral edge, and this bent peripheral edge functions as a sealing member, improving the sealing performance between the metal plate to be processed and the lid-side clamping surface. In addition to this, after the forming process, the bending periphery is in a polymerized state, which increases the rigidity of the periphery of the metal plate to be processed, reducing deformation of the molded product, and improving the forming process. This has the effect of making it easier to take out items.

[Brief explanation of the drawing]

Fig. 1 is a process explanatory diagram explaining a forming method according to an embodiment of the present invention, Fig. 2 is a sectional view of a forming apparatus used in the embodiment forming method, and Fig. 3 shows a bent peripheral portion of a metal plate to be processed. Perspective view,
FIG. 4 is a perspective view showing the bent peripheral edge after the forming process, FIG. 5 is a perspective view showing the other side of the bent peripheral edge, and FIGS. 6 and 7 are explanatory diagrams of the prior art (both figures cross-sectional view). 21...Lid side clamping surface 4--Working metal plate 40...Bending peripheral portion 5...-Airtight chamber

Claims (1)

[Scope of Claims] 1) A mold-side clamping surface formed on the periphery of the mold, and a lid-side clamping surface formed on the periphery of the sealing lid opposite to the mold-side clamping surface, to hold the metal plate to be processed. A clamping step is performed to form an airtight chamber on at least one side of the metal plate to be processed by pinching the peripheral edge of the metal plate, and then the metal plate to be processed is heated to a predetermined temperature at which it becomes a superplastic state. Changing the air pressure in the airtight chamber,
In a method for forming a superplastic metal plate in which the metal plate to be processed is plastically processed by bringing it into close contact with the forming surface of a mold, before the clamping process, the Forming of a superplastic metal plate characterized by forming a bent peripheral edge by bending or curving inward toward an airtight chamber, and in the clamping step, the bent peripheral edge is held between both clamping surfaces. Method.