JPS58202939A - Hot plastic working method - Google Patents

Abstract

PURPOSE:To easily obtain a member of a desired final shape from a material which is expensive and inferior in its workability, by containing a die and a billet in a capsule which causes plastic deformation at a high temperature and under high pressure, and pressing it by hot hydrostatic pressure. CONSTITUTION:A die 2 which consists of a heat resisting material and is provided with a cavity 4 having an opening part, a billet-like base material 3 having a softening point temperature which is below a softening point or decomposition point temperature of said heat resisting material, and a capsule 1 consisting of a gas non-transmitting material which causes plastic deformation at a high temperature and under high pressure are prepared. Subsequently, said die 2 and base material 3 are contained in the capsule 1, a cover 6 is installed and the capsule 1 is sealed by welding 5. Next, the whole capsule 1 is pressed by hot hydrostatic pressure at a temperature at which the base material 3 generates a plastic flow, although the die 2 causes no decomposition nor plastic deformation. Then, the base material 3 is pressed into the inside of the cavity 4, and is deformed along a shape of the cavity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a member having the same contour as a cavity of a molding material by compressively deforming a metal material or a ceramic material in a high temperature range that causes plastic flow, and in particular, a method for manufacturing a member having the same contour as a cavity of a molding material. The present invention relates to a method for forming metal or ceramic members using a press (hereinafter referred to as HIP).

In recent years, isothermal forging has been developed and put into practical use, particularly in the aircraft industry, as a method for manufacturing components close to the final shape by plastically working N1-based superalloys, T1 alloys, or ceramics, which are resource-poor, expensive, and have poor workability. It is served to. This method involves heating a billet-like material to a high temperature and pressing it into a predetermined shape by pressing into a heat-resistant metal mold heated to the same temperature. Although this is a good method for manufacturing gas turbine disks made of N1-base superalloy and centrifugal compressor runners made of T1 alloy, it has the following drawbacks. That is, Ni-based super superalloy 1000~
1200℃, Ti alloy needs to be processed at 1% temperature of 800-950℃, and Mo alloy, which has even better heat resistance, is usually used as the mold material, but Mo alloy cannot be processed at high temperatures in the air. Because it oxidizes and sublimates, it is necessary to place the product and the mold in an inert atmosphere, and the entire equipment, including the handling equipment, becomes extremely expensive and expensive. Not only that, but since it is processed at a low strain rate, 1
It takes more than 30 minutes to manufacture each product, production efficiency is low, and mass production is difficult.

On the other hand, as mentioned above, N1-based superalloys and T1 alloys are expensive and do not have good workability, so powder metallurgy is used to manufacture materials as close to the shape of the final product as possible, improving material yield and reducing processing costs. Efforts are being made to achieve this goal.

As one of such powder metallurgy techniques, H-P
This method has been attracting attention, and is actually used to manufacture billet-shaped materials before being processed using the constant temperature forging method described above. Therefore, if it becomes possible to perform plastic working similar to the isothermal forging method using the HIP method, there will be no need to introduce costly equipment for the isothermal forging method, which will not only reduce capital investment, but also In addition, short cycle (several hours/cycle) HT5. If a P device is used and a large number of objects to be processed can be placed in the H-P device at once, mass production becomes possible, and manufacturing costs can be significantly reduced.

The present invention was completed as a result of intensive research in view of the above-mentioned problems and with the aim of realizing the above-mentioned expected effects.
a mold having a cavity having two openings; and a billet-like material disposed facing the linear cavity opening and having a softening point temperature lower than the softening point or decomposition point temperature of the heat-resistant material. , placed in a capsule made of a gas-impermeable material that undergoes plastic deformation under high-temperature Takata, and after sealing the capsule, the mold as a whole does not decompose or undergo plastic deformation, but the material undergoes plastic flow. The method is to apply hot isostatic pressing at a high temperature such that the material is thickened into the cavity and deformed along the shape of the cavity.

Hereinafter, the method of the present invention will be explained with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of a capsule containing a crab and a billet-like material, which is applied to carry out the method of the present invention.

FIG. 2 shows a sectional view taken along line A--A in FIG. 1, that is, a top view of the mold.

3 to 5 are vertical sectional views showing another embodiment of a capsule containing a mold and a billet-like material used in the method of the present invention, and FIG. 6 is a vertical sectional view taken along the line BB in FIG. 5. It is an arrow sectional view.

FIG. 7 is a perspective view showing the member obtained by the embodiment shown in FIGS. 5 and 6. FIG.

1 and 2, a mold (1) made of a heat-resistant, high-strength material is placed inside a capsule (1) made of metal such as mild steel.
Insert 2). The mold (2) has a cavity (4) which is open at the top, and a cylindrical billet material (3) faces the opening of the cavity (4) and closes it.
) are inserted and arranged. This material (3) has a softening point temperature, that is, a temperature at which it can be plastically deformed, which is lower than the decomposition point or softening point temperature of the heat-resistant material forming the mold (2).

The material (3) and the capsule (1) are hermetically joined by means such as welding (5), and the inside of the capsule (1) is sealed.

The entire capsule thus sealed was loaded into the H-P equipment, and the temperature was raised to a temperature at which mold (2) did not decompose or undergo plastic deformation, but capsule (1) and material (3) could undergo plastic deformation. After that, pressurized gas is injected to compress the whole. Type (2)
is not deformed at this temperature and pressure, so as the pressure increases, the material (3) is forced into the cavity (4) of the mold (2), and is deformed and molded into a shape that follows the contour of the cavity. Take this out of the H-P device and create a capsule (1).
The molded article and the mold (2) are separated by mechanically or chemically removing them.

The material of the mold (2) is appropriately selected depending on the type of material (3) and the HIP treatment temperature.
Oxide ceramics such as alumina can be used when the H-P treatment is carried out at temperatures below Celsius, but nitride ceramics such as silicon nitride are used when the H-P treatment is carried out at temperatures higher than that.

Carbide ceramics such as silicon carbide, molybdenum alloys, Wolfham alloys, graphite, etc. can be used. Materials for capsule (1) and mold (2): When metal is used for binding, capsule (1) and material (3), material (3) and mold (2).

Alternatively, since the capsule (1) and the mold (2) may be diffusion bonded at the interface, it is preferable to apply boron nitride or the like as a mold release agent to the interface in advance.

The billet-like material to which the method of the present invention can be advantageously applied is not particularly limited, and includes N1-based superalloys and Ti alloys.

Fθ-based alloys, cobalt, chromium, wolfram, vanadium, molybdenum, etc., and alloys thereof.

Various ceramics such as carbides and nitrides can be mentioned, among others, N1-base superalloys, Ti alloys and... Particularly preferred are e-based alloys.

Capsule (1) [It plays the role of preventing pressure medium gas from entering the interior during H-P processing, and also acts as a pressure transmitting diaphragm that applies the hydrostatic pressure of the pressure medium to the sample. Materials that exhibit plasticity under pressure, are sufficiently airtight at processing temperatures, and can be easily removed from molds and molded articles by mechanical or chemical methods in the final stage are desirable.

From this point of view, iron, molybdenum, niracle.

Metals such as platinum, glass, etc. are used.

The combination of the mold (2), the material (3), and the capsule (1) is the key point in the method of the present invention, and the mold (
The material constituting 2) is required to be as heat-resistant as possible, and its softening point or decomposition temperature is higher than that of the material (3).
The softening point temperature of the capsule (1) must be much higher than the temperature at which plastic deformation or plastic flow can occur, and the material of the capsule (1) at least softens at the softening point temperature of the material (3) and becomes plastic under pressure. It is necessary to choose something that can be transformed.

Under such a combination of the three, the temperature at which the HIP treatment is performed is such that mold (2) does not decompose or plastically deform;
It is important to select and control the material (3) to such an extent that plastic flow occurs, and for the other H-work P conditions, conventionally commonly used conditions can be adopted.

In addition, after the capsule (1) is sealed, it is subjected to the H-P treatment, but if the temperature is raised in the H-P apparatus a without degassing the inside of the capsule, nitrogen and oxygen in the air present in the capsule will be removed. These gases are eventually absorbed into the billet-like material, but since these gas absorption reactions, oxidation reactions, etc. mainly occur in high temperature regions, gas absorption reactions hardly occur during the first ascent stage. As the temperature rises, the gas inside the capsule expands and the capsule is subjected to internal pressure. For example, when a sealed capsule at room temperature is heated to 500 to 600 degrees Celsius, the internal pressure will be about 3 atm, and the strength of the capsule material (for example, soft mould) will drop significantly due to the high temperature. As a result, the capsule expands and deforms due to its internal pressure and eventually breaks, causing various inconveniences.

Therefore, in such a case, it is necessary to raise the pressure as well as the temperature and carefully set a HIP operation program so that the above-mentioned adverse effects do not occur. As a result, the gas inside the capsule is eventually absorbed by the billet-like material1, and the extremely small amount of oxide produced has virtually no negative effect on quality, and may even result in a favorable nitriding reaction. . Further, even if an oxide film is formed on the surface of the molded article, it may be preferable because it may actually hinder the diffusion bonding with the mold (2) and facilitate the release of the molded article after the HIP treatment. However, on the other hand, it is often necessary to avoid the formation of such oxides, especially when diffusion bonding is performed at the same time as molding using multiple billet materials. It is preferable to provide a suitable recess in the inner wall and fill it with getter material. The getter material is a substance that can absorb the gas remaining in the capsule, especially oxygen, even at elevated temperatures, and has titanium, zirconium, niobium, silicon, vanadium, aluminum, or any of these as the t component. Particularly preferred are foils, thin wires, or green compacts made of at least one metal from the group consisting of alloys.

When a sealed capsule in which such a getter material is placed at an appropriate location communicating with the cavity (4) is subjected to H-P treatment, as the humidity increases, it will be adsorbed to the surface of the mold (2) and the material (3). The gas component that was
Since it is adsorbed by the getter material together with the air remaining in the cavity (4), the formation of harmful compounds such as oxides on the surface of the molded product is almost completely prevented.

However, in the above method, the time required to occupy the expensive H-P process increases (the cycle time required for H-P process increases), and the efficiency decreases significantly. It is preferable to preheat to shorten the HIP treatment time.

When preheating is applied to the method of the present invention, the mold (2) and the billet material (3) are placed in the capsule (1) and then charged into a preheating furnace without being sealed, and the inert gas such as nitrogen gas is 1000℃~ depending on the mold material, raw material, etc. in the atmosphere
Heat to 1500°C or one degree below.

The preferred preheating temperature is the capsule sealing operation after completion of preheating,
The temperature is at least equal to or slightly higher than the HIP processing temperature in anticipation of cooling during charging into the HIP equipment. Once preheating to a predetermined temperature is completed, the capsule is sealed and subjected to H-processing. 1 In this way, when the capsule is sealed immediately after preheating,
For example, when preheated to about 1000°C, 70% of the internal gas
~75% is released from the force due to thermal expansion, and the amount of internal residual gas rl'i is reduced to 25-30% of normal temperature, which is virtually the same as when sealed under reduced pressure, and the adverse effects of oxygen. can be kept to a minimum.

The above example shows the case where the mold (2) and billet material (3) are all housed in the capsule (1), sealed without completely deaerating the inside, and then subjected to the H/P treatment. capsules (1
) It is preferable to substantially completely deaerate the interior or remove adsorbed moisture before sealing the container. For example, a degassing pipe is connected to the capsule (1), the temperature is raised as necessary, vacuum suction is applied, and then the capsule is sealed. Figure 3 shows an example of a capsule for this purpose.

In the same figure, after inserting the material (3) into the capsule (1), a lid (6) with a degassing pipe (7) is attached,
The structure is made airtight by welding (5).

When the temperature of the whole is raised, the gas adsorbed on the mold (2) and the material (3) is released and the moisture is evaporated.

In this state, the pipe (7) is connected to a vacuum pump (not shown), and after vacuum suction is applied, the pipe (7) is crushed.

After forge welding, the excess pipe is removed and the whole is subjected to HIP treatment. In such a case, even if the raw material (3) is a porous body such as a pre-sintered body, a sufficiently high quality and dense molded body can be obtained.

FIG. 4 shows an example of molding an integrated gas turbine rotor. In this case, the mold is constructed by combining two parts: type (i) and type (2). Insert the mold (25 (2ff) into the capsule (1) and insert the material (3)
After fitting, the lid (6) with the deaeration pipe (7) is attached and made airtight by welding. After that, the process is carried out in the same procedure as in the case of FIG. 3 above.

5 and 6 show an example in which the cavity (4) formed by combining the molds (i) and (4) opens upward and toward two sides. That is, the upper opening The material (3) is placed so as to face the part and close it,
Also, facing the circular opening on both sides are the materials (3).
(3) is arranged and the whole is housed within the rectangular capsule (1). In this case as well, vacuum suction is applied through the degassing tube (7) to sufficiently remove internal gas, moisture, etc., and the capsule is sealed and subjected to the H/P treatment.

The material (3) press-fitted from the upper opening and the r〃 material +8) (3) press-fitted from the side opening merge inside the cavity (4) due to the static water use in the H engineering P process, and each Since the surfaces contact each other in a clean state without being oxidized at all, good diffusion bonding is achieved and a homogeneous and dense molded body is obtained as a whole.

FIG. 7 shows the molded body thus obtained.

In the method of the present invention, by predetermining the volume or weight of the billet-like material corresponding to the volume of the cavity, it is possible to obtain a molded product that roughly matches the shape of the cavity at once, reducing the time and effort required for finishing and molding. Generation of waste can be minimized. That is, it is possible to easily manufacture a member having a shape close to a desired final shape from expensive [and poor workability] N1-based superalloys, T1 alloys, ceramics, etc. with high efficiency and high yield.

In addition, according to the method of the present invention, since forming is performed by H-processing, the existing H-processing equipment installed for billet production and other purposes in 1.1 can be used as is, and new equipment can be used. It does not require any investment, and if a large number of capsules are charged and processed in the H-P furnace at the same time, mass production becomes possible in conjunction with the recent shortening of the H-P processing cycle. In this way, compared to the conventional constant temperature forging method, which requires a huge investment in equipment and requires similar operations in an inert atmosphere, the inefficient production system of one piece per cycle has been completely eliminated.
A significant streamlining power is achieved by the present invention.

Next, aspects of the present invention will be described with reference to examples.

Example 1 A capsule (S
(manufactured by US 304) while heating to 0°C. This was placed in a HIP device, and after reducing the argon gas pressure in the device by 50°C, the temperature was raised and maintained at 1100° C. After 30 minutes, argon gas was gradually injected under pressure to obtain 650 class. After reaching 650 l, it was held for 2 hours, then the temperature was lowered and the pressure was reduced.

The capsule was taken out from the fHXP apparatus, the capsule was removed by turning, and the product was taken out. The shape of the obtained product had almost the same shape and contour. 1 Example 2 Tl-6At- with a diameter of 80 m and a thickness of 70111I
The 4V alloy material was vacuum-sealed at room temperature into the same capsule (made of mild steel) as in the fourth case together with an alumina mold. This is H
Put it into the equipment and set the argon gas pressure inside the equipment to 50! After reaching A, the temperature was raised and maintained at 930° C. After 30 minutes, argon gas was injected under pressure to set the temperature to 60 oyA.

After holding at 650 jaws for 1 hour, the temperature was lowered and the pressure was reduced. After removing the capsules in the same manner as in Example 1, the product was taken out. The shape of the obtained product had almost the same outline as the mold.

[Brief explanation of the drawing]

Fig. 1 is a vertical side view of a capsule containing a mold and a billet material applied to the method of the present invention, Fig. 2 is a cross-sectional view taken along the line A-A, and Figs. Figure 5 is a vertical cross-sectional view showing another embodiment of the capsule containing the mold and billet-like material used in the method of the present invention, No. e! The figure is B- in Figure 5.
FIG. 7 is a sectional view taken along the line B, and FIG. 7 is a perspective view showing the member obtained by the embodiment shown in FIGS. 5 and 6. (1)・・・・・・・・・・Capsule, (2)・・・
・・・・・・・・・Type. (3)・・・・・・・・・・Billet-like material, (4
)·······cavity.

Claims (1)

[Scope of Claims] 1. A mold comprising a cavity made of a heat-resistant material and having at least one opening; A billet material having a softening point temperature lower than the point temperature is placed in a capsule made of a gas-impermeable material that undergoes plastic deformation under high temperature and high pressure, and after the capsule is sealed, the mold is decomposed into the entire capsule. Alternatively, the material is pressed into the cavity by hot isostatic pressing at a high temperature that does not cause plastic deformation but causes plastic flow of the material, and the material is deformed along the shape of the cavity. Inter-plastic processing method. 2. The hot plastic working method according to claim 1, wherein the capsule is sealed after being preheated in an inert gas atmosphere. 8. The hot plastic working method according to claim 2, wherein the preheating is performed to reach a temperature at least comparable to the temperature of hot isostatic pressing. 4. The hot plastic working method according to claim 1, wherein the capsule is sealed after being vacuum degassed. 5. Claim 4 in which vacuum deaeration is performed at elevated temperature
Hot plastic working method described in section. 6. Any of the above claims in which the billet-like material is an N1-based superalloy, a T1-based alloy, or a lie-based alloy.
Hot plastic working method described in. 7. The hot plastic working method according to any one of the claims above, wherein the mold is made of alumina, silicon nitride, silicon carbide, molybdenum alloy, Wolfram alloy, or graphite. 8. The hot plastic working method according to any one of the claims above, wherein boron nitride is applied as a mold release agent to the interface between the material, the mold, and the capsule.