JP2528461B2 - High temperature fluid pressure compression method for materials - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for densifying mainly the inner surface quality of various materials to be compressed by performing a high temperature isotropic pressure treatment.

(Prior Art) There are many known methods for molding a powder material into a solid.

In order to improve the density to 100% or a value close to 100%, it is necessary to give a high compressibility at high temperature by forging, rolling, extruding, etc., or to apply high isotropic pressure at high temperature by HIP (hot isotropic compression). is necessary.

For parts with complicated shapes, HIP using argon or nitrogen gas as a pressure medium is suitable, but it has the disadvantage of high cost due to complicated mechanism, use of expensive gas and long cycle time. However, it is currently applied only to high-grade parts.

Hydraulic HIP (Japanese Patent Laid-Open No. 58-22307) is known as a method that can greatly reduce the cycle time. However, the heat resistance of the material used for the press container and There is a problem of sealing property against high temperature liquid, and it seems that much improvement efforts are required to put it into practical use.

In order to eliminate these drawbacks of HIP, a series of technologies collectively called pseudo-HIP was developed (The International JoP
urnal of Powder Metallurgy and Powder Technology J
ULY 1985). Typical examples thereof include a Ceracon method using ceramic particles as a pressure medium, an ROC method using a pressure medium such as a metal having fluidity at high temperature, and ceramic particles.

The present inventor has proposed two methods for improving the sealing property and heat resistance when glass or a low melting point metal is used as a pressure medium in a liquid state. One of them is Sho Akira
No. 61-315654 (Japanese Patent Laid-Open No. 63-168295), in which a material to be compressed heated to a required temperature is placed in a pressing container having an opening hole in a cylinder part on which a pressing punch slides. At the initial stage of compression, at least in the initial stage of compression, a layer of granular material having a relatively low temperature is present between the punch and the fluid when isotropically press-compressing the fluid heated to a required temperature as a pressure medium. Proposed a press compression method in which the punch did not come into contact with the fluid. This method solves the problem of sealability.

The second method is Japanese Patent Application No. 62-3185 (Japanese Patent Laid-Open No. 63-174799), in which a material to be processed is encapsulated together with a granular pressure medium, and the capsule structure is heated to a required temperature. The liquid pressure medium is heated to a lower temperature and housed in a pressing container, and the capsule structure, which is the material to be compressed, is pressed and compressed.

At this time, the granular substance in the capsule has both a function as a pressure medium and a heat insulating function between the liquid pressure medium and the material to be processed. This method improves the heat resistance of the press container, but in order to improve the sealing property,
It is desirable to use the first method together.

As described above, the granular material can be interposed between the punch and the liquid pressure medium to improve the sealing property, but there is a drawback that the workability is slightly deteriorated.

That is, in order to realize a good seal, it is necessary to make the layer of the above-mentioned granular material into a layer having a uniform thickness on a horizontal plane, but a uniform charging device and a uniform stirring device for this are required.

(Problems to be Solved by the Invention) The present invention is intended to develop a method for simplifying charging of the above-mentioned granular material into a container for pressing with a uniform thickness and performing sealing more completely.

(Means for Solving Problems) In the present invention, a material to be compressed heated to a required temperature is charged into a pressing container having an opening hole of a cylinder portion on which a pressing punch slides. , When a fluid heated to an appropriate temperature is isotropically press-compressed as a pressure medium, a layer of granular material, which is a low-temperature object formed in advance as an integral shape, is interposed between the punch and the fluid. And

Practically, this low-temperature object is a molded body which is the same substance as the high-temperature liquid and is granular, which is formed in advance into a shape having a desired thickness t by giving a diameter inscribed in the press container in advance.

The above-mentioned molded body may be one obtained by sintering a granular material or one obtained by compression molding. Further, it may be a molded body in which a granular material is solidified with a caking material to form an integral shape.

Hereinafter, the above-mentioned molded body is referred to as a press molded body in the present invention.

The press-molded body is slidably loaded into a press container, but there is a working gap Δg between the inside of the container and the outer diameter of the press-molded body. However, according to experiments, the press-molded body is compressed in the vertical direction during the compression-molding of the punch, and is flatly expanded in the radial direction to completely close the gap Δg, which is excellent in the ability to cover the entire surface of the high-temperature liquid. ing.

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

FIG. 1 is an explanatory diagram of the present invention, and FIG. 2 is an explanatory diagram of the operation of the present invention.

In the figure, 1 is a press container, 2 is a punch, 3 is a material to be compressed, 4 is a high temperature liquid, 5 is a press molded body, 6 is a punch projection, and 7 is a press molded body recess.

As the material to be compressed 3, for example, a material in which a powder material such as metal powder or ceramic powder is filled in a capsule, or a material in which powder material such as metal powder or ceramic powder is compression-molded by a press machine or the like is used. There are many.

The press molded body 5 has a thickness t, and is a side wall of the press container 1.
It is inserted into the press container with a gap Δg between 1-2. It is convenient to evenly apply the pressure by forming the concave portion 7 on the upper surface of the press-molded body 5 and fitting the concave portion 7 into the protrusion 6 of the punch 2, but the present invention is not limited thereto.

The press-molded body 5 may normally be at room temperature (room temperature), but may be at a high temperature within the range where the whole is not liquid. Reference numeral 8 denotes a portion where the high-temperature fluid 4 when the press-molded body 5 is inserted is rapidly cooled and becomes solid, and has a function of preventing the high-temperature fluid from rising during pressing.

The press-molded body 5 and the punch 2 are integrated by the pressing operation of the punch 2, but as the compression progresses, the press-molded body 5
Is flatly expanded in the radial direction, and Δg disappears (second
Figure). Therefore, the press-molded body 5 completely covers the high-temperature fluid 4 and exhibits excellent sealing properties.

In the method described above, the material does not have to be the same as that of the granular material that is a low-temperature object integrated with the high-temperature fluid, but in terms of workability, it is often convenient for both to be the same material.

This is because, even when these substances are repeatedly used in the press container or when they are circulated and repeatedly used, if these pressure media are the same material, the work of separating the two becomes unnecessary. is there.

However, in this case, the melting point or softening temperature of this material must be between the temperature of the high temperature fluid and the temperature of the particulate matter. The processing temperature is when the material to be compressed is stainless steel.
It is about 700 ℃ to 1300 ℃. Therefore, taking the case of stainless steel as an example, the melting point or softening temperature of this pressure medium must be between 700 ° C and 1300 ° C and room temperature. Glass can be given as an example of such a material. For example, the softening temperature of lead soda glass is about 630 ° C, and that of aluminosilicate glass is 920 ° C.
It is about ℃. Also, many glasses having a high softening temperature are known.

Further, a low melting point metal such as lead, copper, aluminum, or an alloy containing these as the main components can also be used.

Next, a method of forming the granular material having the above-mentioned materials into an integral structure will be described.

One is a method in which these granular materials are cold pressed and then sintered at an appropriate temperature, or these granular materials are sintered by hot pressing.

In this case, it is not necessary to make the density very high, and it is sufficient to use a light sintered body that can be handled as an integral structure. Further, if the molded body is formed in the shape of a briquette, it is not always necessary to sinter.

The other is a method in which these granular materials are combined with a suitable caking material to form a monolithic structure. For example, it is preferable to use ceramics or a high melting point metal as the granular substance, and use the same glass or low melting point metal as the liquid pressure medium as the caking substance. The mixing and molding of these particulate materials and the caking substance are performed at a temperature at which the caking substance is easily mixed.

When the monolithic structure of the granular material solidified with the caking material is used at the time of press compression, it is preferable to heat it so that it has a fluidity such that it does not deform during handling.

Hereinafter, other application examples of the press-formed product of the present invention will be shown.

FIG. 3 shows an example of application to a composite billet manufactured by the molten metal forging method.

The SiC whisker preform 15 is heated in the press container 1 and then set, and the molten Al alloy 14 is poured into the press container 1 from the ladle 16. Next, a press-molded body 5 which is a light-sintered body of granular Al alloy is provided and pressed by the punch 2.

According to the present invention, the sealing effect of the press-formed product 5
A SiC whisker compact can be efficiently impregnated with an Al alloy.

 FIG. 4 shows an example of hydrostatic pressure / extrusion.

As shown in the figure, the die 11 is set with the billet 25 and the fluid substance
24. For example, glass is poured and the press molded body 5 which is a light sintered body of granular glass is set. When the punch 2 pressurizes, the molded product 26 is obtained from the die 11, but due to the excellent sealing effect of the press-molded body 5, the fluid substance 24 does not leak.

(Example) SUS304 stainless steel powder having a particle size of -100 mesh was compressed to a density of 70% by a cold press. The dimensions of this compression molded product are
It is 10mmφ x 10mm high.

 This was pressed by the system shown in FIG.

Aluminosilicate glass was used as the high-temperature fluid and the press-molded body at room temperature. Average particle size of granular glass
The thickness of the press molded body was 1 mm and the thickness t was 30 mm.

The high temperature fluid temperature is 1200 ℃ and the press compression force is 40ton. However, the punch diameter is 40 mmφ. The height of the high temperature fluid layer is 100 mm.

By pressing for 1 minute under these conditions, the density is almost
A 100% molded product was obtained. This is the same effect on the internal quality as obtained with HIP.

(Effects of the Invention) As described above, it was demonstrated that a molded product having the same quality as that obtained by the conventional HIP can be obtained in the range of 10 minutes per cycle. This is a remarkable effect compared with the conventional HIP in which one cycle lasted for more than one hour.

Further, when the particulate matter is used as the upper layer of the high temperature fluid, it is necessary to consider the uniformity of the particulate matter layer, but in the present invention, since it is a press-molded body, the operation is simple.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the present invention, FIG. 2 is an explanatory diagram of the operation of the present invention, and FIGS. 3 (a), 3 (b) and 4 are explanatory diagrams of an application example of the present invention. 1; Press container, 2; Punch 3; Material to be compressed, 5; Press molded body

Claims (2)

(57) [Claims] 1. A material to be compressed, which has been heated to a required temperature, is charged into a pressing container having an opening hole of a cylinder part on which a pressing punch slides upward, and separately heated to an appropriate temperature. When a fluid is used as a pressure medium and isotropically compressed, the punch does not come into contact with the fluid at least in the initial stage of compression by allowing a molded body in which a granular material is integrally molded in advance to exist between the punch and the fluid. A high-temperature fluid pressure compression method for materials, which is characterized in that the material is press-compressed in this manner. 2. A method for compressing a material under high temperature fluid pressure according to claim 1, wherein the molded body which is previously molded into an integral shape is a molded body obtained by consolidating granular substances with a caking substance.