JPS5850281B2 - Molding method for irregularly shaped objects using hot isostatic pressing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot isostatic pressing method for easily and simply molding irregular objects having various irregular shapes.

Hot isostatic pressing method (hereinafter referred to as HIP method) is a method for processing various materials under high temperature and high pressure gas atmosphere.
This method is widely known and attracts attention, and is expected to be used for sintering cemented carbide powder.

The alloy sintered by this method has the advantage that the structure, density, mechanical properties, etc. of the sintered body are superior to those obtained by conventional sintering methods, and it can be sintered at low temperatures. have.

However, in the current HIP method, the object to be processed is sealed in a capsule and the product shape is regulated in advance by the capsule. A unique mold was required, and the price of the capsule became a large proportion of the price, leading to an increase in manufacturing costs.

However, the molding of irregularly shaped articles by the HIP method is
It not only expands the industrial use of the method, but also fundamentally changes the conventional manufacturing process of irregularly shaped articles, making irregularly shaped articles that were previously expensive due to high production costs, both in terms of quality and economically. It has the characteristics that can be provided to the public, and its utilization is strongly desired.

In order to cope with the above-mentioned situation, the present inventors have been conducting research for some time on a HIP processing method that can easily mold even irregularly shaped articles that are virtually difficult to obtain using conventional HIP methods. As a result, we found a method in which a metal mold, ceramic mold, etc. is first matched to the shape of the irregularly shaped product, and a product shape is created using a sheet-like material such as paper or plastic inside the capsule, and refractory powder is used as a support material. We have come up with a separate proposal for how to use it.

However, as a result of continuing research, each of the above methods is effective and has an effective role depending on the shape of the product and the purpose of use of the HIP method. We found that there is room for improvement.

The present invention further develops the above-mentioned technical idea based on such knowledge, and uses double capsules for the inside and outside, and the inner capsule is made of a material that is inexpensive and decomposes at HIP temperature. The powder to be treated is placed inside the capsule, while the outer capsule has a relatively simple shape, and both are held via a refractory powder surrounding layer.
It is characterized by performing P processing.

Hereinafter, if the specific contents of the method of the present invention are explained step by step, the first feature of the present invention is that the method has two different sizes:
The method is to use several capsules.

FIG. 1 illustrates an embodiment of the present invention using two capsules, an inner and outer capsule. In the figure, 1 is an outer capsule, 2 is an inner capsule, 3 is a refractory powder, and 4 is a raw material powder to be processed. .

The outer capsule has a relatively simple shape and is made of conventional capsule materials, such as metal or glass.

On the other hand, the inner capsule 2 is different from the outer capsule 1 and has a complicated shape depending on the intended shape. The material must be such that it decomposes at a HIP temperature of .

Examples of such materials include plastics such as polyethylene and vinyl chloride, and relatively thin sheet-like materials such as paper.

These materials of the inner capsule 2 are burned out and dissolved during the HIP process, causing decomposition.

Note that the size ratio of the outer capsule 1 and the inner capsule 2 is such that the inner capsule 2 is stored three-dimensionally within the outer capsule 1;
Preferably, the size is large enough to form a layer of refractory powder filling between the two capsules.

The refractory powder 3 filled between the inner and outer capsules 1 and 2 includes ceramic powder such as alumina, glass powder, salt, etc., and is appropriately selected and used depending on the type of raw material powder 4 to be processed, HIP processing conditions, etc. Ru.

In this case, a part of the refractory powder 3 is mixed with a material capable of absorbing or adsorbing elemental gases such as O 2 , N, CO, H2, etc. that are generated as the inner capsule 2 decomposes, and You may also arrange it.

Titanium powder, nickel powder, etc. are usually considered as the absorbing or adsorbing material.

When molding a required irregular shape according to the method of the present invention using the two inner and outer capsules 1 and 2 as described above, first, high-speed steel powder or other sinterable metal alloy powder is placed in the inner capsule 2. , ceramic powder, mixed powder thereof, etc. are selected and filled according to the article to be molded, and stored in the outer capsule 1 with a layer of refractory powder 3 interposed therebetween.

In this case, the inner capsule 2 is surrounded by three layers of refractory powder and is completely buried within the outer capsule 1.

Note that the part filled with the raw material powder 4 to be processed inside the inner capsule 2 and the inside of the outer capsule 1, that is, the part filled with the refractory powder 3, may or may not be vacuum degassed.

Thus, after the placement of both the inner and outer capsules 1 and 2 is completed,
This capsule is sealed and placed in a furnace under a high temperature, high pressure atmosphere and subjected to the usual HIP treatment. We will set appropriate conditions and implement them from time to time.

During the HIP process, the inner capsule 2 is made of a material that decomposes as described above, so it is burned out or melted down and decomposed, and the elemental gases such as 0, N, and C that are generated at this time are diffused outside the inner capsule 2. However, if an absorbing or adsorbing material is mixed in, it will be absorbed or adsorbed and will not affect product quality at all.

Next, an example of implementing the method of the present invention will be given.

(Example) High-speed steel powder (steel type T15) is used as a raw material powder and is filled into a plastic case made of polyethylene of a desired irregular shape, and then covered with a plastic lid made of the same material. It was stored in a mild steel outer capsule container as shown in Fig. 1, and the remaining space was filled with alumina powder.

After filling, a lid was welded to the mild steel container as shown in FIG. 1, the container was sealed without degassing, and HIP treatment was performed under the conditions of temperature, pressure, and time shown in FIG. 2.

In addition, in FIG. 2, changes in pressure surrounded by dotted lines are increases or decreases in pressure associated with increases or decreases in temperature.

When the HIP-treated container thus obtained was cut and its condition observed, it was found that the alumina powder had not been compacted at all, the inner plastic case had been burned away, and irregular-shaped objects were found as shown in Figure 3. Got the product.

Considering this condition, it was found that the irregular shaped material obtained by HIP treatment had good structure and density, and was also excellent in mechanical properties.

As described above, according to the method of the present invention, inexpensive and HIP
An inner capsule and an outer capsule that decompose at temperature are used, and the inner capsule is configured according to the desired irregular shape.
Since it is housed in an outer capsule and subjected to HIP processing through a layer of refractory powder, it is difficult or extremely expensive to create it by simply adjusting the inner capsule to the desired shape of the irregular object using conventional HIP processing. It is possible to easily and simply manufacture complex irregularly shaped products that are economically unsuitable for manufacturing, and in particular, by significantly reducing the cost of the inner capsule, combined with its ease of moldability, the cost of irregularly shaped products can be significantly reduced. It has the effect of reducing costs in terms of costs, and increases the variety of products as well as mass production by molding the inner capsule, promoting not only the production of a wide variety of small quantities of irregularly shaped products, but also the mass production of the same product. It has the remarkable effect of widening the scope of industrial use of.

The inner capsule is made of a material that decomposes at the HIP processing temperature, and has a mold release effect due to decomposition, making it easy to take out the article, and has the characteristics of smoothly performing the HIP process. This method is extremely superior in terms of both workability and economy.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a processing capsule showing an example of the main part of the embodiment of the method of the present invention, FIG. 2 is a chart showing HIP processing conditions,
FIG. 3 is a diagram showing an example of a product obtained by the method of the present invention. 1... Outer capsule, 2... Inner capsule, 3... Refractory powder, 4... Raw material powder to be treated.

Claims (1)

[Scope of Claims] 1. In a method for manufacturing irregularly shaped articles from powder material by hot isostatic pressing, an inner and outer capsule consisting of an inner capsule 2 having a shape according to the desired shape and an outer capsule 1 having a relatively simple shape. Two capsules are used, and the inner capsule 2 is made into a shape according to the desired shape of the irregularly shaped article using a material that can be decomposed by hot isostatic pressing, and the raw material powder 4 to be processed is filled into the inner capsule 2. , a molding method for molding irregular objects using a hot isostatic pressing method, characterized in that the refractory powder 3 is stored in an outer capsule 1 through a surrounding layer, and then subjected to a hot isostatic pressing process. 2. A method for molding a profile by hot isostatic pressing according to claim 1, wherein the material of the inner capsule 2 is plastic. 3 Claim 1 in which the material of the inner capsule 2 is paper
A molding method for molding irregular objects using the hot isostatic pressing method described in Section 1. 4. A molding method for molding a profile by hot isostatic pressing according to claim 1, 2 or 3, wherein the material of the outer capsule 1 is metal. 5. A molding method for molding a profile by hot isostatic pressing according to claim 1, 2 or 3, wherein the material of the outer capsule 1 is glass. 6. A method for molding irregular objects by hot isostatic pressing as described in each of the claims 1 to 5, wherein the refractory powder 3 is a ceramic powder. 7 Claim 1 in which the refractory powder 3 is glass powder
A molding method for molding irregular objects by the hot isostatic pressing method described in each item. 8 Claim 1 in which the refractory powder 3 is aluminum powder
A molding method for molding irregular objects by the hot isostatic pressing method described in each item. 9. A variant molded by the hot isostatic pressing method described in each of claims 1 to 8, in which the refractory powder 3 partially contains an adsorbent for gas generated as the inner capsule 2 decomposes. Monodori type method.