JPH044998A - High isostatic compressing method for material - Google Patents

Abstract

PURPOSE:To execute high density compression to a composite material by arranging gap through which granule of a material to be compressed does not pass but lubricating liquid passes at between a die and punches in a high isostatic pressing machine. CONSTITUTION:At the time of compressing the material to be compressed by incorporating the material to be compressed into the dies 3 in the pressing machine as surrounding this with the pressing medium and descending the punch 1, mixture of the granule of ceramic and metal and the lubricating liquid of oil, grease, etc., is used as the pressing medium. Then, at between the die 3 and the punches 1, 2, the gap having size, through which a large part of the granule does not pass but the lubricating liquid passes, is arranged. By this method, the high isostatic compressing work under the room temp. and high temp. can be executed to obtain the high compressed density product.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention belongs to the technical field of producing single parts of various materials with high functionality by rapidly compressing powder materials, cast materials, or composite materials to high density.

Conventional technology The technology for compressing these materials to high density at room temperature is as follows:
CIP (Cold Isostatic Pressing)
atic Pressing) is known (Reference: The International Jour
nal of powder metallurgy
and Powder Technology, Ju
12.1985).

Problems to be Solved by the Invention In the conventional CIP method, after charging the material to be compressed together with a pressure medium such as water or oil into a pressure vessel, the pressure medium is made to have a high pressure by increasing the pressure with a pressure pump. The material to be compressed is compressed.

There is also a method (press method) in which a material to be compressed is placed in a press mold together with a pressure medium such as water or oil, and then high pressure is generated by mechanically compressing the pressure medium with a punch.

However, in either method, it is essential to seal the pressure medium to prevent it from leaking from the pressure vessel or the press die, and the level of sealing technology determines the ultimate pressure and safety.

Furthermore, although the press method has high productivity, the sealing performance is inferior compared to the pressure vessel method, so the possible pressure that can be generated is low. The present invention relates to a method that employs a highly productive press method and can generate high hydrostatic pressure without sealing.

Means to solve the problem We have considered various ways to solve the above problem.
It has become clear that the following method is optimal.

In other words, the material to be compressed is stored in the die of the press machine so that it is surrounded by a pressure medium, and the punch is lowered to compress the material to be compressed. A mixture of a body and a lubricating liquid such as oil or grease is used, and a gap is created between the die and punch that is large enough to allow the lubricating liquid to pass through, although most of the powder and granules mentioned above do not pass through. be.

An example of the configuration of such a device is shown in the first factor. In this example, a powder encapsulated in a rubber capsule is used as the material to be compressed, as in ordinary CIP. 1 is upper punch, 2
is the lower punch, and 3 is the die. 6 is a powder material, and 7 is a rubber material for capsules. 4 is a spherical ceramic grain, 5
is grease. In this way, the load from the punch is borne by the ceramic grains, and the grease acts as a lubricant between the ceramic grains.

That is, since the grease does not need to act as a pressure medium, it may leak from the gap between the die and the punch. Therefore, according to this method, no special sealing technology is required, so high-pressure, high-speed compression processing is possible. In the case of a normal pressing method using only the upper punch, and when the above-mentioned grease is not used, only a portion of the upper punch pressure reaches the lower punch due to friction between the ceramic grains and the die and friction between the ceramic grains.

An example of a load-stroke diagram during pressing is shown in FIG. 2. D=80 mm, H=100+am, and the ceramic grains are spherical alumina powder with an average size of 60 μm.In Figure 1, a is the upper punch load, and b is the lower punch load. When grease is mixed with this alumina powder, the lower punch load increases as shown in C and becomes almost the same as the upper punch load.

Although this experiment was conducted at room temperature, compression processing at high temperatures is also possible as long as the lubricating liquid does not decompose. In particular, if glass is used as the lubricating liquid, compression processing at high temperatures of 1000° C. or higher becomes possible.

Example D = 8 (is■, H = 100■■), and spherical alumina grains with an average diameter of 0.5 layers and grease were used as the pressure medium.The clearance between the punch and the die was 0.
2+sm. The material to be compressed has an outer diameter of 20 mm and a wall thickness of 1.
Iron powder is vacuum sealed in a cylindrical rubber capsule measuring 20 mm in diameter and 20 mm in height. Upper punch load is 100t
I turned it on. The pressurization time was 1 minute. After pressurization, the material to be compressed had an outer diameter of 25 mm and a height of 10 l, but had a barrel-shaped deformation in which the diameter at the center in the vertical direction was slightly larger than at both the upper and lower ends. Note that the diameters of the upper and lower end surfaces were almost the same. When the rubber capsule was removed and the densities at the top, middle, and bottom three locations were measured, they were all about 7.5, reaching approximately 85% in terms of relative density.

Effects of the Invention The present invention has high productivity and enables high isostatic pressure compression processing at room temperature and high temperature.

[Brief explanation of the drawing]

FIG. 1 shows an example of the basic configuration of an apparatus for carrying out the present invention. FIG. 2 is a load-stroke diagram when an experiment was carried out using equipment E shown in FIG. 1-... Upper punch, 2... Lower punch, 3... Dice, 4... Spherical ceramic grain, 5... Grease, 6...
... Powder material, 7... Rubber material for capsules, D...
Fist die inner diameter, H, φ, die inner height, a, b... Φ, upper punch load and lower punch load, respectively when using only ceramic grains as pressure medium, C...mixture of grease with ceramic grains Lower punch load when

Claims (1)

[Claims] The material to be compressed is stored in the die of the press machine so that it is surrounded by a pressure medium, and when the material is compressed by lowering the punch, ceramic or metal powder and oil are used as the pressure medium. This method uses a mixture of lubricating liquids such as oil and grease, and has a gap between the die and the punch that is large enough to prevent most of the powder and granular material from passing through, but allows the lubricating liquid to pass through. Hydrostatic compression method.