JPS5840976Y2 - Hot isostatic press equipment - Google Patents

Description

[Detailed description of the invention] This invention uses the hot isostatic pressing method (HIP) to create pores that exist inside objects to be processed, such as cast products, sintered bodies, or various mechanical parts that have intergranular cavities due to creep. This equipment is used to improve the mechanical properties and reliability of objects to be processed, especially in order to prevent the surface layer of the objects from being contaminated by impurity components in the pressure gas. The present invention relates to a hot isostatic press apparatus equipped with a pressure medium gas purification device for supplying extremely high-purity pressure medium gas to a high-pressure vessel.

In recent years, the HIP method, which processes various materials in a high-pressure, high-temperature gas atmosphere, has been attracting attention.

Various applications have been proposed for this method, one of which is the field of application that removes various pores existing inside the object to be processed and makes the material defect-free, which has recently been in the spotlight. There is.

Such internal defects include, for example, cavities in cast products, intergranular cavities due to creep that occurs when used for long periods of time under high temperature and high stress, or sintered products manufactured by normal sintering methods. There are pores inside.

When a workpiece with these internal defects is subjected to HIP treatment, the internal defects are crushed due to the synergistic effect of high pressure and high temperature, and diffusion bonding progresses, causing the originally existing internal defects to completely disappear, leaving no trace of them. No residue remains, and the object to be processed is made healthy.

As a result, specifically, the following advantages are obtained.

That is, in the case of cast products: (1) Since macroscopic defects are also eliminated, defective products can be salvaged, and yields are significantly improved.

(2) Increased ductility which significantly improves elongation drawing.

(3) Fatigue strength is significantly improved.

(4) Creep characteristics are significantly improved.

(5) Dispersion in characteristic values is reduced and reliability is dramatically improved.

(6) Weldability is improved.

(7) Electrochemical processability is improved.

On the other hand, in the case of intergranular cavities due to creep, HIP treatment can be applied to materials that have been used for long periods of time under high temperature and stress, such as gas turbine blades, and have intergranular cavities due to creep. , it is possible to restore its characteristics to the same level of performance as new.

This has extremely important significance from the standpoint of resource conservation.

Thus, HI for materials with these internal defects
There are many innovative effects of P.

However, when this technology is actually used industrially, it is said that the biggest technical problem is the contamination of the surface layer of the object to be processed by impurity components in the pressure gas.

Moreover, this problem becomes particularly noticeable when processing Ni-based alloys, Ti alloys, and the like.

First of all, since high pressure gas is used in HIP, the influence of impurities in the gas is large.

For example, if Ar gas with a total impurity content of 200 ppm is used, under a high pressure of 1000 atm, simply thinking:
The absolute amount of impurities is 200ppIIl=200X10'
, therefore 200X10-6XIO3 (atmospheric pressure) 0.2=2
0%, which is comparable to processing in normal pressure Ar gas containing 20% impurities.

However, in reality, since there is a temperature effect, the amount of impurities is 1/1/2 of this.
3, or about 6%.

Under these assumptions, HIP typically uses 900-
A temperature of about 1200°C is applied.

However, at such temperatures, each component element in the object to be processed is highly activated and easily reacts with impurities in the pressure medium gas to form oxides, nitrides, carbides, and the like.

In particular, oxygen as an impurity is the biggest problem, and even if several thousand meters of oxygen exists, an oxidized contamination layer of several tens of micrometers will be formed on the surface of the object to be processed, and the characteristics of the object will be significantly deteriorated. , in severe cases, it becomes completely unusable.

Therefore, when used industrially, some kind of gas purification is required in order to recycle and use the pressure medium gas.

One possible solution to this problem is to completely cover the outer surface of the object with a capsule, but in this method, after HIP treatment,
Separating the capsule from the object to be processed takes a lot of effort, and if the object to be processed has a complicated shape, it is difficult to mold the capsule into such a shape and encapsulate the object to be processed inside it. There are problems such as extreme difficulty, and it has not been put into practical use.

In addition, HI can be used for members such as Tarpier members, which have been used for long periods of time under high stress, causing distortion in the crystal grains, creating intergranular cavities due to creep, and deteriorating mechanical strength.
A method of restoring the parts to their original state by P treatment is also being considered, but since the formation of a contamination layer is not allowed on such parts, further contamination countermeasures are required.

The present invention aims to solve these problems and put the reforming technology into practical use using the HIP method.The present invention is characterized by the fact that a compressor is installed in the supply line that supplies pressurized gas from the gas holder to the high-pressure vessel. In addition, a reactor filled with a metal having a strong affinity for oxygen and equipped with a heating device is arranged in series with the compressor.

Hereinafter, the device of the present invention will be explained in further detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows a flow sheet of the device of the present invention. In the figure, 1 is a high pressure vessel, 2 is a pressure medium gas holder, and a pressure medium gas supply line 7 is formed between the gas holder 2 and the high pressure vessel 1. On the other hand, a gas recovery line 8 is formed between the high pressure container 1 and the gas holder 2.

Further, 3 and 4 are low-pressure and high-pressure compressors arranged in the gas supply line 7, and 5.5' is a reactor arranged in series with the compressor and configured to be switchable between the two. are provided with heating devices 6, 6' for heating.

The reactors 5 and 5' contain a metal having a high affinity for oxygen, such as Al.

T t z S t z Mg p Nb t V t
A single element such as Zr, an alloy thereof, or an iron alloy thereof is filled in the form of powder, granules, ground powder, or a mixture thereof, and is contained in the pressure medium gas supplied to the high-pressure vessel 1. Reacts with oxygen and removes oxygen from the gas.

In addition, this metal with a strong oxygen affinity is used only by itself,
In addition to filling, it is industrially possible to mix and increase the amount of ceramic powder to prevent sintering of these metals.

In addition, although two reactors 5 and 5' are installed in the illustration,
In terms of operation, one number of units may be sufficient, but from the viewpoint of operability, it is of course desirable to install a plurality of units and operate them selectively so that continuous operation can be performed even during the process of replacing deteriorated metal.

In addition, the positions of the reactors 5 and 5' are as shown in the figure.
If it is placed on the discharge side of the gas flow rate, the reaction will proceed under high pressure, so the reaction rate will be faster and the reactor can be made smaller, but pressure resistance will be required, so the gas flow rate,
It goes without saying that an appropriate location, such as between the internal compressors 3 and 4 or on the inlet side of the low-pressure compressor 3, can be selected in consideration of pressure and the like.

Note that 1 to 9 are valves disposed in the gas supply/recovery line, and 6 in particular is a pressure reducing valve.

7. In the device of the present invention, outside the supply/recovery line, from the rear of the pressure reducing valve 6 on the recovery line 8 side, the gas supply line 7 reaches the front of the low pressure compressor 3, and passes through the low pressure compressor 3 to the gas holder. A forced recovery line 9 that returns to the inlet side of 2,
9' is provided to make recovery of the pressure medium gas to the gas holder 2 efficient.

Next, the working mode of the device of the present invention constructed as described above will be explained. First, when the object to be processed is charged into the high-pressure container 1, the valve ①1. ■2. ■3. ■Open 4 or v4' and supply the pressure medium gas of about 150 atm from pressure gas holder 2.
The container 1 is filled and pressurized using a low pressure compressor 3 and a high pressure compressor 4 until the internal pressure of the container 1 reaches a predetermined pressure (for example, about 1000 atm).

During this time, while the pressure gas passes through either of the two reactors 5, 5' which are maintained at a high temperature by the heating devices 6, 6', oxygen in the pressure gas flows into the reactor. The pressurized gas is removed by reacting with the filled metal, and the pressurized gas is purified and supplied into the high-pressure vessel 1.

Note that Al is used as the metal filled in the reactors 5 and 5'.
If a metal with a strong nitrogen affinity such as , Ti, Nb, or V is used, the impurity nitrogen in the pressure medium gas will be removed at the same time. In such a case, a metal such as Si or Mg that selectively removes impurity oxygen is used, and in any case, the pressure medium gas is purified in the reactors 5 and 5' and sent to the high pressure vessel 1. It is boosted and supplied within.

After boosting the pressure, valve ■1) V2 t Va , V4 p V
4' is closed and the object to be processed is subjected to HIP processing according to the usual method. When the HIP processing is completed, first, valve 5. ■6. 7 is opened and the pressure medium gas is recovered through the recovery line 8 0 Since the inside of the high pressure vessel 1 is maintained under high pressure, the pressure medium gas is initially recovered naturally due to the differential pressure between the inside and outside of the high pressure vessel 1. However, if the internal pressures of the high-pressure container 1 and the gas holder 2 are balanced, natural recovery becomes impossible, and the pressure gas is reduced to about 150 atmospheres using the pressure reducing valve V6 and passed through the recovery line 8. Since the flow of pressure medium gas to 8 is stopped, valve 7 is closed, and valve 8 is closed. ■, release and force flffllA
Through the collection line 9゜9', the pressure is increased by the low pressure compressor 3 and forced recovery is performed, and when the pressure inside the high pressure container 1 drops to about several atmospheres to 10 atmospheres, valves ■, ~■, are closed to recover the pressure medium gas. finish.

Air (nitrogen,
Since the pressure medium gas inside the container is contaminated by CO2H2, etc. generated by the mixing of oxygen) and the decomposition of oil adhering to the object to be treated, the pressure medium gas purified in the reactors 5 and 5' and supplied to the high pressure container 1. becomes an impure gas and is collected in the gas holder 2.

If the pressure medium gas initially supplied to the high-pressure container is purified, the amount of impurities mixed in during the above HI filtration process will not be large enough to cause a problem of contamination of the object to be processed, but this contamination will If the pressurized gas is repeatedly used, impurities will accumulate in the pressurized gas, causing a problem of contamination of the object to be treated.

In the present invention, by providing the reactors 5 and 5' in the gas supply line, purified pressure medium gas is constantly supplied to the high-pressure container, which prevents the accumulation of impurities and contamination of the object to be treated. There is no problem.

Further, as mentioned above, the reactors 5 and 5' are filled with metal having a strong affinity for oxygen, and because they react with oxygen to form oxides, it is necessary to change and use them periodically.

Note that other impurities other than oxygen, such as hydrogen and nitrogen, are
Hydrogen can be removed as appropriate by utilizing the difference in boiling point with r.
A device that removes nitrogen or the like, such as an adsorber, can also be used in combination.

Incidentally, as a device similar to the present invention, the present applicant previously proposed a device in which the above-mentioned reactor was placed in the gas recovery line 8, but it was found that this device had various problems, so the present invention was proposed. The differences between the two devices will be described below by comparing them with the previous device.

(1) As the HIP device becomes larger, it takes time to recover the gas, and the HIP cycle tends to become longer.

Therefore, in order to shorten the HIP cycle, it is necessary to increase the gas recovery speed, but if this is increased, when the reactor is installed in the gas recovery line, it is necessary to ensure the specified gas residence time in the reactor. It becomes necessary to increase the size of the reactor.

However, this increase in size is related to the thermal efficiency of the heating devices 6, 6', and has its own limits, so installing a reactor in the gas recovery line is an effective way to increase the gas recovery rate and shorten the HIP cycle. Acts as an inhibiting factor.

On the other hand, since the gas velocity in the gas supply line is necessarily determined by the compressor capacity, the reactor capacity of the present invention is uniquely determined in correspondence to the compressor capacity.

(2) Since the gas recovery rate changes with time, when a reactor is installed in the gas recovery line, the gas residence time will differ, and if the reactor is designed for the maximum speed at the initial stage of recovery, the reactor will become larger and If the design is performed under conditions lower than this, there is a risk that almost no impurities will be removed at the initial stage of recovery, and these impurities will gradually accumulate.

In the present invention, the gas velocity is substantially constant, so there is no such problem.

(3) When performing gas purification in the gas recovery line, purified pressure medium gas must be supplied into the high-pressure vessel, and therefore a large amount of expensive high-purity gas must be prepared as the initial pressure medium gas. It won't happen.

However, in this invention, which performs gas purification in the gas supply line, it is possible to use inexpensive low-purity gas, so taking into account the regular replenishment of pressure gas, the cost of pressure gas, which accounts for the majority of HIP costs, can be significantly reduced. can be lowered to

As mentioned above, air intrusion into the high-pressure container accompanying the unavoidable operations for loading and unloading objects to be processed into the high-pressure container 1 and thermal decomposition of oil adhering to objects to be processed during the HIP process occur. Pressure medium gas is contaminated by impurity gases, etc., but with the device of the present invention, the contaminated pressure medium gas is recovered as it is, purified at the time of supply, and recycled to the high pressure vessel. There is no accumulation of impurity gas in the medium gas, so HIP processing can be performed without contaminating the object to be processed with impurities, and high-grade alloys such as superalloys can be completely sealed. At the same time, since an inexpensive low-purity gas can be used instead of an expensive high-purity pressure gas, it is possible to significantly reduce the cost of the pressure gas, which accounts for most of the HIP cost.

[Brief explanation of the drawing]

The figure is a flow sheet showing an overview of the device of the present invention. 1... High pressure container, 2... Pressure medium gas holder, 3... Low pressure compressor, 4... High pressure compressor, 5, 5'... ...Reactor, 6,6'...
... Heating device, 7... Gas supply line, 8.
...Gas recovery line, 9,9...Bypass line, ■1~■, ...Valve.

Claims (1)

[Scope of utility model registration request] 1. A pressure medium gas from a pressure medium gas holder 2 is pressurized into a high-pressure container 1 containing an object to be processed through a compressor, and hot isostatic pressure is applied to the object to be processed in a high-temperature, high-pressure gas atmosphere within the container. In a hot isostatic press device that performs a press treatment and then recovers the pressure medium gas in the container into the pressure medium gas holder 2, the pressure medium gas is supplied from the pressure medium gas holder 2 into the high pressure container 1. A gas supply line 7 and a gas recovery line 8 for recovering pressure medium gas from the high pressure vessel 1 to the pressure medium gas holder 2 are provided, and the gas supply line 7 is equipped with compressors 3 and 4 and a metal having a strong oxygen affinity. 1. A hot isostatic press apparatus characterized in that reactors 5 and 5' are arranged in series, filled with reactors 5 and 5' and equipped with a heating device 6°6'. 2. Metals with strong oxygen affinity are Al, Ti, Si, and Mg. The hot metal according to claim 1, which is one or more metals selected from the group consisting of Nb, V, Zr alone, alloys thereof, or powders, granules, or cutting powder of iron alloys thereof. Hydrostatic press equipment. 3. Hot isostatic press apparatus according to claim 1 or 2 of the utility model registration claim, in which a metal with strong oxygen affinity and ceramic powder are mixed and filled in the reactor.