JPH06238355A - Superplastic forming composite mold and superplastic forming method - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a composite mold for superplastic forming. [Structure] (1) A superplastic forming composite mold in which a gap between a die box 2 and a forming mold 3 is filled with a granular material 4. (2) A method of heating the die box 2 and the molding die 3 to a superplastic temperature, then filling the gaps between the die box 2 and the molding die 3 with the granular material 4, and then performing superplastic molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite mold for superplastic forming and a superplastic forming method using the composite mold.

[0002]

2. Description of the Related Art In superplastic forming, a superplastic forming is made by combining a forming die for obtaining a desired shape and a container (hereinafter referred to as a die box) for accommodating, sealing and reinforcing the forming die. It is known that a composite type may be used. This composite mold for superplastic forming is prepared by forming molds of different sizes or shapes and one die box, exchanging the molds and performing superplastic forming.
Superplastic molded products having different shapes can be obtained.

Both the mold and the die box may be made of heat-resistant cast steel, but the mold may be made of ceramics and the die box may be made of heat-resistant cast steel. This is because the ceramic molding die is capable of precisely molding even finer patterns than the heat-resistant cast steel molding die.

[0004]

When there is a gap between the molding die and the die box during superplastic forming using the above-mentioned composite die for superplastic forming, the superplastic material plate enters the gap, The plastic material plate may be torn.

For this reason, superplastic forming is carried out after setting the mold and the die box so that there is as little gap as possible. However, as long as the mold and the die box can be separated, It is necessary to provide a gap that allows the mold to be easily inserted into the die box. Furthermore, even if the mold can be set so that there is no gap between the mold and the die box, for example, a ceramic mold and a cast steel die. When superplastic forming is performed using a superplastic forming composite mold that has different materials, such as a box superplastic forming composite mold, the materials may have different coefficients of thermal expansion, so they may be combined at room temperature without gaps. Even if possible, it is unavoidable that a gap will be generated at high temperature, and the phenomenon especially in the case of a large-sized composite mold for superplastic forming appears remarkably, which is a problem in superplastic forming. .

[0006]

Therefore, the present inventors have
As a result of research to solve the problem of superplastic forming, when the gap between the forming die and the die box is filled with granules and / or powder to intervene, the gap between the forming die and the die box is filled. Research results have been obtained that the granules and / or powders that have disappeared and have a function of adjusting a gap caused by a difference in thermal expansion coefficient between the mold and the die box are obtained.

The present invention was made based on the results of such research, and it was found that a die box and a molding die were
It is characterized by a superplastic forming composite mold that is filled with granules and / or powder.

As the material of the above-mentioned granular material and / or powder, a sphere made of ceramics or metal can be used, and the size thereof is not particularly limited, but the portion contacting with the superplastic material plate is too fine. If the material is used, it becomes difficult to insert the superplastic material plate into the plate after the superplastic forming, so that it is difficult to peel the plate. The granules and / or powders filled in the gap between the molding die and the die box may lower the surface in contact with the superplastic material plate during high temperature and superplastic forming, but there is almost no problem in superplastic forming. If it becomes a problem in a later step or the like, it can be solved by replenishing the granular material and / or powder by the reduced amount after reaching the superplastic forming temperature.

FIG. 1 is a sectional view of a composite mold for superplastic forming of the present invention. In FIG. 1, 1 is a top plate, 2 is a die box, 3 is a forming die, 4 is a granular material, and 5 is superplastic. Material plate, 6
Is a supply hole. To perform superplastic forming using the composite die for superplastic forming of the present invention, the forming die 3 is placed in the die box 2.
Is charged and installed, the die box 2 and the molding die 3 are heated to a superplastic molding temperature, and then the gap between the die box 2 and the molding die 3 is filled with the granular material 4. The granules 4 may be filled before heating the die box 2 and the molding die 3. However, if the granules 4 are fine, the granules 4 are sintered and adhered, and the die box 2 and the molding die 3 are integrated. In some cases, the die box 2 cannot be separated because it cannot be separated. Therefore, it is preferable to fill the granular material 4 after heating the die box 2 and the molding die 3 so as not to sinter during heating.

After filling the granular material 4, the superplastic material plate 5
Is placed on the die box 2, the top plate 1 is placed thereon, and the forming gas is supplied from the supply holes 6 to perform superplastic forming.

[0011]

【Example】

Example 1 As a superplastic material plate, 25% Cr-6% Ni-by weight%
It has a composition of 3% Mo-Fe and has a thickness of 0.5 mm.
Phased stainless steel sheet is prepared, and silica ceramics containing a small amount of alumina (coefficient of thermal expansion: 1.8 × 10 ⁻⁶ /
C.) forming mold and a heat-resistant steel (coefficient of thermal expansion: 16 × 10 ⁻⁶ / ° C.) die box equivalent to SUS310 were prepared.

On the other hand, as a granular material, a ceramic sphere with a diameter of 2 mm, a ceramic sphere with a diameter of 5 mm, and a diameter:
10mm ceramic spheres are prepared respectively, and these granules have a diameter of 5mm and a diameter at the part where they contact the superplastic material plate.
Ceramic balls of 10 mm were mixed and arranged, and superplastic forming was performed under the superplastic forming conditions of temperature: 980 ° C., gas: Ar, gas pressure: 18 kg / cm ² .

As a result, the superplastic material plate does not flow into the gap between the forming die and the die box and break.

Example 2 A Ti alloy plate having a composition of 6% Al-4% V-Ti and a plate thickness of 1.6 mm was prepared as a superplastic material plate, and silica ceramics containing a trace amount of alumina was prepared. A mold made of (coefficient of thermal expansion: 1.8 × 10 ⁻⁶ / ° C.) and a die box made of heat-resistant cast steel corresponding to HK-20 (coefficient of thermal expansion: 18 × 10 ⁻⁶ / ° C.) were prepared.

On the other hand, as the granules, the ceramic spheres having a diameter of 5 mm and the ceramic spheres having a diameter of 10 mm prepared in Example 1 were used, and the ceramic spheres having a diameter of 10 mm were arranged in the portion in contact with the superplastic material plate. , Temperature: 900 ℃, gas: Ar, gas pressure: 10kg / cm ² , when superplastic forming was performed under superplastic forming conditions, the superplastic material plate flowed into the gap between the forming die and the die box and broke. Never happened.

[0016]

EFFECTS OF THE INVENTION When the superplastic forming composite die of the present invention is used, even if the die box and the die having various shapes and sizes smaller than the opening of the die box are used in combination, the die box and the die The gap between the particles or
And because it is filled with powder, it is necessary to pay attention to the gap that is caused by the difference in coefficient of thermal expansion between the die box and the mold, unlike the conventional case where the superplastic material plate enters the gap and is not broken. Therefore, it has an excellent effect that superplastic forming work can be performed easily and quickly.

[Brief description of drawings]

FIG. 1 is a sectional view of a superplastic forming composite mold of the present invention.

[Explanation of symbols]

 1 Top Plate 2 Die Box 3 Mold 4 Super Grain 5 Super Plastic Material Plate 6 Supply Hole

Claims (3)

[Claims] 1. A composite mold for superplastic molding, comprising a granular material and / or a powder filled between a die box and a molding die. 2. The composite mold for superplastic forming according to claim 1, wherein the die box is made of metal and the forming die is made of ceramics. 3. The method of heating a die box and a forming die to a superplastic forming temperature, filling granules and / or powder between the die box and the forming die, and then performing the superplastic forming. Superplastic forming method.