JPS62290801A - Isotropic pressurization method - Google Patents

Abstract

PURPOSE:To make quick, easy and uniform pressure molding of a material to be molded by heating the material packed into a molding tool by the through flow of a heating gas, then subjecting the material to isotropic pressure molding by a liquid pressure medium in a pressure vessel. CONSTITUTION:The material to be molded (powder of metal, etc.) 1 is packed into the molding tool 2 (heat resistant rubber, etc.) and air permeability is provided thereto so that the material has about 50-80% voids. The material 1 to be molded is then heated from the outside of the tool 2 by a 1st heating means 8 and at the same time the heating gas is allowed to flow through the material 1 by a 2nd heating means 9 by which the material 1 is heated up to a prescribed temp. The tool 2 is immersed in the liquid pressure medium in the pressure vessel 15 of an isotropic pressurization device upon ending of the heating and is subjected to the pressure molding by a liquid pressure medium feeding and discharging means 24; thereafter the molding is subjected to a deaeration treatment by a gas venting means 21. The pressure molding of the material 1 while maintaining the same in the heated state is thereby executed and the uniform pressure molding is facilitated.

Description

[Detailed description of the invention] 3. Detailed description of the invention (industrial application field) The uninvented invention is to heat an air-permeable molded object such as a powder of metal or ceramics to produce isotropic liquid pressure medium. The present invention relates to an isostatic pressing method for forming under pressure.

(Prior art) Conventionally, the cold isostatic pressing method was developed as an isostatic pressing method in which an air-permeable molded object such as a powder is heated and molded by isotropic pressure of a liquid pressure medium. Warm range (50℃ ~
There is a warm isostatic pressing method in which pressure molding is performed at a temperature of 400°C.

As shown in Figure 5, this warm isostatic pressing method
By enclosing a molded body 31 made of powder such as ceramics into a mold 32 made of an elastic body such as rubber, and circulating a hydraulic medium heated by a hydraulic medium supply/discharge means 34 into a pressure vessel 33. , a molded object 31 is pressure molded in a pressure vessel 33 by isotropic pressure of a heated hydraulic medium.

(Problems to be Solved by the Invention) According to the above-mentioned warm isostatic pressing method, the molded object is heated from the outside via the mold by the heating hydraulic medium, so it is possible to When heating a body, it takes a long time to heat the center of the body. As a result, temperature unevenness occurs between the inside and outside of the molded object, with the temperature becoming lower from the outer part to the inner part of the molded object, making uniform pressure molding difficult. In the case where a binder is added, a reaction layer of the binder is generated on the surface of the molded object before the heat is transferred to the inner part of the molded object,
This may result in molding defects.

An object of the present invention is to solve the above-mentioned problems by externally heating the molded object before charging it into the pressure vessel.

(Means for Solving the Problems) The specific means adopted by the present invention to achieve the above object is characterized by heating the permeable molding material filled in the mold 2. Pressure vessel 15 of isostatic pressurization device
In the method of pressure molding in a liquid pressure medium inside the molded body 1, heated gas is made to flow through the inside of the molded body 1 outside the pressure vessel 5 before the pressure molding is carried out using an isostatic pressurizing device. After heating the molded object 1, the mold 2 is placed in a pressure vessel 15 while maintaining the heated state of the molded object 1, and isotropically pressure-molded using a liquid pressure medium.

(Function) A heated gas is made to flow through the inside of the molded object 1 in order to heat the molded object 1 having air permeability filled in the mold 2. Then, the object 1 to be formed is charged into a pressure vessel 15 while being kept in a heated state, and isostatically pressed using a liquid pressure medium.

(Example) Hereinafter, the configuration of the present invention will be explained in detail.

A molded object such as a breathable material, such as a powder such as metal or ceramics, or a porous ceramic, or a solid material such as carbon, or an elastic body such as heat-resistant rubber or resin, or a thin-walled material such as aluminum or copper, etc. A mold made of an elastically deformable material with a low softening temperature is filled, and before this mold is pressurized with a liquid pressure medium in a pressure vessel of an isostatic pressurizing device, the outside of the pressure vessel is The molded object is heated to a predetermined temperature by flowing heated gas through the inside of the molded object. Thereafter, the mold is placed into a pressure vessel while maintaining the heated predetermined temperature of the molded object, and isotropically pressure molded using a liquid pressure medium.

At that time, the object to be formed is heated to about the preheating temperature, the mold is placed in a pressure vessel, and the object is pressurized with a liquid pressure medium, or
Alternatively, after the object to be formed is heated to the required temperature for pressure molding, the mold may be placed in a pressure vessel and pressure molded using a liquid pressure medium.

In addition, when heating the object to be formed to the required temperature for pressure forming, it is desirable to set the temperature to a temperature that takes into consideration heat radiation loss during the transition to the step of pressure forming the object. Before this, it is preferable to remove adsorbed gas from the object to be molded and the inner surface of the mold, vacuum seal it, and then perform isostatic pressure molding.

Embodiments will now be described in detail with reference to the drawings showing the apparatus used in the invention.

Reference numeral 1 denotes an object to be molded, which is made of powder of ceramics, metal, etc., and is filled inside the mold 2 . This mold 2 has a mold body 3 made of heat-resistant rubber or thin-walled aluminum, copper, etc., a lid 5 having a circulation hole 4 for supplying and discharging heated gas, and a lid 5 that is located on the entire inside surface of the M5 and that prevents powder from flowing. It consists of a porous body 6 made of an air-permeable material that does not pass through.

7 is an external heating device, which before charging into the pressure vessel 15,
The external heating device 7 heats the molded object 1 externally, and this external heating device 7 includes a first heating means 8 that heats the molded object 1 from the outside of the mold 2, and a heated gas inside the molded object 1. It consists of a second heating means 9 that heats the molded object 1 by causing the flow to flow through it. The first heating means 8 includes a heat insulating layer 10 surrounding the mold 2, a heater 11, etc., and the second heating means 9 includes a heater 12 and a blower 13, and is connected to the communication hole 4 of the lid 5 of the mold 2. ing.

That is, before pressure forming the molded object 1, the molded object 1 is heated from the outside via the mold 2 using the external heating device 7, and heated gas is made to flow through the inside to bring the molded object 1 to a predetermined temperature (preheating temperature, heating temperature, etc.). (including both pressing temperatures). On this occasion,
The object to be formed 1 is also heated from the outside by the first heating means 8, so it is heated more uniformly in a short time, and the mold 2 is also heated, so that it is not exposed to heat during the process of pressure forming after heating. Heat radiation loss of the molded body 1 is reduced. Note that since the powder generally has a porosity of 50 to 80% in a naturally filled state, it has sufficient air permeability to allow heated gas to flow through it.

Next, after closing the M5 flow hole 14 of the mold 2 with the stopper 14, the mold 2 is placed into a pressure vessel 15 of an isostatic pressurizing device, and a liquid pressure medium such as water is poured into the pressure vessel. 15 and the pressure is increased, the liquid pressure medium is isotropically molded.

In FIG. 2, reference numeral 15 indicates a pressure vessel of a warm isostatic pressurizing device that performs isotropic pressure molding using heated liquid.
The mold 2 is immersed in a liquid pressure medium inside the pressure vessel 15, and an upper lid 115a and a lower lid 15b are fitted to the upper and lower open ends of the pressure vessel 15 in a removable and airtight manner, respectively. A piping hole 17 for deaeration is formed in a manner communicating radially outward from the plug 14 at the upper part of the mold 2.
is connected to gas degassing means 21 having a relief valve 18, a check valve 19 and a pump 20.

A boat 22 , 23 for supplying a hydraulic medium is formed in the lower xisb, and this boat 22 , 23 is connected to a hydraulic medium supply/discharge means 24 . The liquid pressure medium supply/discharge means 24 includes a Wi-ring pump 26 having a viroft check valve 25 connected to the boat 21, a viroft check valve 27 connected to the boat 23, and an ultra-high pressure pump 29 having a check valve 28. The supply side of the pumps 20 and 26 and the discharge side of the check valve 28 are connected to the liquid pressure medium heating device 30, respectively.

That is, the pressure vessel 1 is heated while maintaining the heated state of the molded object 1 heated to about the preheating temperature or the required temperature for pressure molding.
It is immersed in the heated liquid pressure medium of No. 5 to perform a deaeration treatment and is then pressure-molded.

Note that when the object to be formed 1 is preheated, a liquid pressure medium heated by the heating device 30 to a predetermined pressure forming temperature is supplied and the pressure is increased by the ultra-high pressure pump 29. The same applies when the object 1 to be formed is externally heated to a predetermined pressure molding temperature and the temperature is slightly lowered.

In FIG. 4, reference numeral 15 designates a pressure vessel of a cold isostatic pressing device for pressure-forming the molded object 1 by applying the pressure of a liquid pressure medium such as water or oil. The object 1 to be formed is preheated to the pressure forming temperature by the heating device 7, and then placed in the pressure vessel 1. A liquid pressure medium is supplied to the inside of the pressure vessel 15, and this pressure medium is used to perform isotropic molding. It is press-molded.

An upper IE 15a and a lower lid 15 are installed at the upper and lower open ends of the pressure vessel 15.
b are airtightly fitted so that they can be freely inserted and removed, and the bottom! ! 1
5b is formed with a boat 22.23 for supplying and discharging a liquid pressure medium, and this boat 22, 23 is connected to a liquid pressure medium supply means (not shown).

That is, the molded object 1 heated to the required temperature for pressure molding is immersed in a liquid pressure medium in the pressure vessel 15 while maintaining the heated state to perform pressure molding. At that time, in the mold 2 made of heat-resistant rubber, the heat-resistant rubber acts as a heat-retaining layer, and the aluminum,
The mold 2 made of copper or the like is heated in advance to a temperature that takes heat radiation loss into consideration. Furthermore, it is desirable that the inside of the mold 2 be degassed before being charged into the pressure vessel 15.

In addition, in FIGS. 2 and 4, F indicates a press frame. In addition to powder, the object to be molded 1 may be a porous material, a carbon block, a sheet-like laminate, etc. In any case, the mold 2 is filled with heated gas flowing through it. It's fine as long as it's possible.

(Effects of the Invention) As described in detail above, according to the present invention, the molded object is heated by flowing heated gas through the inside of the molded object before the molded object is charged into a pressure vessel and pressure-formed. Since the molded object is heated, even if the molded object is large or thick, the temperature of the molded object can be uniformized in a short time, and uniform pressure molding can be easily performed. In addition, since the object to be formed is heat-treated outside the pressure vessel,
This also has the effect of shortening cycle time.

[Brief explanation of the drawing]

Figures 1 to 4 show an example of an apparatus directly used in the present invention. Figure 1 is a sectional view of an external heating device in which a mold is charged, and Figure 2 is a sectional view of an external heating device in which a mold is charged. Fig. 3 is a sectional view of the warm isostatic press device filled with a molded object, and Fig. 4 is a sectional view of the cold isostatic press device loaded with a mold. , FIG. 5 is a sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1... object to be formed, 2... mold, 7... external heating device, 15... pressure vessel, 21... degassing means, 24
...Liquid pressure medium supply and discharge means.

Claims (1)

[Claims] (1) Air permeable molded object 1 filled in mold 2
In a method of heating and pressure-forming in a liquid pressure medium in a pressure vessel 15 of an isostatic pressurizing device, the to-be-molded material is After the object 1 to be formed is heated by flowing heated gas through the inside of the object 1, the mold 2 is charged into the pressure vessel 15 while maintaining the heated state of the object 1 to be formed, and the mold 2 is heated by a liquid pressure medium. An isostatic pressing method characterized by unilateral pressure molding.