JPH06316744A - Production of fe-ni-co series alloy parts for sealing - Google Patents

Abstract

PURPOSE:To produce Fe-Ni-Co series alloy parts for sealing having a complicated shape in a short time by adding alloy fine powder having specified compsn. constituted of Ni, Co and Fe with agar and water as a binder, kneading them, executing injection molding and sintering it. CONSTITUTION:Alloy powder with <=30mum average grain size constituted of, by weight, 27 to 34% Ni and 12 to 19% Co, and the balance Fe with inevitable impurities is added with agar and water showing a sol-gel reaction according to temp. as a binder, and they are kneaded and thereafter subjected to injection molding. This binder is constituted of 1 to 4% agar and 5 to 15% water and furthermore preferably contains, as a lubricant, 0.05 to 0.5% stearic acid and 0.01 to 0.5% sodium tetraborate according to necessary. The molded body obtd. by the same is subjected to heating to about 20 to 100 deg.C at about <=90 deg.C/hr temp. rising rate and dehydrating and is thereafter subjected to debindering and sintering in a vacuum or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing Fe-Ni-Co alloy parts for sealing by injection molding, in which complex shaped parts can be manufactured by adding agar and water as a binder and injection molding. In addition, the present invention also relates to a method for manufacturing a Fe-Ni-Co based alloy component for sealing, which is capable of significantly shortening the time required for the debinding process and shortening the manufacturing process time.

[0002]

2. Description of the Related Art Among hermetically sealed components,
Many of the rapidly developing optical communication-related parts are small and have complicated shapes. Currently, these parts are Fe-Ni-C
A large number of manufacturing steps are required because it is manufactured by cutting a mass of o-based alloy or the like into a predetermined shape, or after forming various shapes of members by assembling into a predetermined shape by brazing and molding. Needed and expensive.

Conventionally, Fe-Ni-based and Fe-Ni-Co-based sealing alloys have been manufactured by processes such as melting, rolling and heat treatment. In recent years, however, molten alloys have been atomized by conventional methods. After being pulverized into powder having a predetermined particle size by various methods such as a powder, a binder, for example, a thermoplastic resin such as polyethylene or wax is added to the powder and mixed,
By the so-called powder metallurgical method of molding, degreasing and sintering,
A method of obtaining a sintered body (Japanese Patent Publication No. 61-48563) has been attempted. In particular, the use of an injection molding device during molding has the advantage that a sintered sealing material of any shape, such as a three-dimensionally complicated shape, can be obtained as it is, which is useful.

[0004]

Fe-N for sealing as described above
When manufacturing an i-Co alloy part, the manufacturing method in which a thermoplastic resin is used as a binder for injection molding requires a long time for the debinding step, and the molded body can be manufactured only with a relatively thin material of 6 mm or less. There is a problem.

This invention is intended for sealing Fe- by injection molding.
In a method for manufacturing a Ni-Co based alloy part, a thick part can be manufactured without using a thermoplastic resin as a binder, and Fe-Ni-C for sealing which can shorten the manufacturing process time.
It is intended to provide a method for manufacturing an o-based alloy component.

[0006]

The inventor of the present invention has made it possible to manufacture a complex-shaped part and to shorten the manufacturing process time.
As a result of various studies on binders instead of thermoplastic resins for the purpose of injection molding method of -Ni-Co alloy parts, thick parts can be manufactured by using agar and water which show sol-gel reaction depending on temperature. The inventors have completed the present invention by finding that the manufacturing process time can be shortened.

That is, the present invention relates to a method of manufacturing a Fe-Ni-Co alloy part for sealing by injection molding,
Ni 27-34 wt%, Co 12-19 wt%, balance F
e and unavoidable impurities, and an average particle size of 30 μm
Fe-Ni- for sealing, characterized in that the alloy powder as described below is mixed with agar and water as a binder, kneaded, and then molded into a predetermined shape by injection molding, and then the molded body is sintered.
It is a method for manufacturing a Co-based alloy component. Further, in the invention, in the above-mentioned constitution, the binder is composed of 1 to 4% by weight of agar and 5 to 15% by weight of water, and 0.05 to 0.5% by weight of stearic acid and 0.01% of sodium tetraborate as a lubricant.
Fe for sealing, containing ~ 0.5 wt%
A method for manufacturing a Ni-Co based alloy component.

Reason for limitation In the Fe-Ni-Co based alloy powder which is the subject of the present invention, Ni is a basic component of the present alloy, and in the finally obtained sintered sealing material, Ni exceeds 34 wt%. And the thermal expansion property becomes too large, and if it is less than 27 wt%, the α phase is generated in the alloy, so that the thermal expansion becomes too large, which is not preferable, and it is out of the scope of the sealing alloy object of the present invention. It will be. Further, although Co is a basic component of the present alloy, like Ni, in the finally obtained sintered sealing material, when Co exceeds 19 wt%, the thermal expansion property becomes too large and the cost is preferable. If it is less than 12 wt%, the magnetic transformation point becomes too low, and the coefficient of thermal expansion up to about 450 ° C. becomes large, which is not preferable. As the alloy powder composition, in addition to the powder of the required composition alloy, a composite of powders of each element and alloy composition to obtain the target composition can be used.

The reason why the average particle size of the Fe-Ni-Co alloy powder to which the present invention is applied is limited to 30 μm or less is as follows.
This is because if it exceeds 30 μm, the sinterability is deteriorated and the sintered density is lowered, and it is more preferably 5 to 15 μm.

Agar as a binder, which is a feature of the present invention, undesirably lowers the strength of the molded product when the amount added is less than 1 wt%, and undesirably increases the amount of binder when it exceeds 4 wt%, and there is a risk of density decrease due to residual carbon. There is not preferable. Further, if the amount of water is less than 5 wt%, the fluidity at the time of molding will be poor, and if it exceeds 15 wt%, the strength of the molded body will decrease, and deformation and variation due to drying will be unfavorable.

In the present invention, a lubricant can be added to the binder, and stearic acid and sodium tetraborate are particularly preferable. Stearic acid improves the wettability of the metal powder and the binder and reduces the viscosity at the time of mixing.
If it exceeds 5% by weight, the strength of the molded body decreases, which is not preferable.
0.05 to 0.5 wt% is desirable. However, it is necessary to appropriately adjust the shape and particle size of the metal powder. If the sodium tetraborate is less than 0.01 wt%, the agar strength will decrease, and if it exceeds 0.5 wt%, it will remain inside and the density will decrease, which is not preferable, and 0.01 to 0.5 wt% is desirable. In the present invention, the amounts of lubricant and binder can be appropriately selected within the above range depending on the molding apparatus, molding pressure, powder composition, and the like.

The injection conditions vary depending on the amount of binder added, but the mold temperature is preferably 10 to 30 ° C, and 10 ° C.
If it is less than 60 ° C, the fluidity is deteriorated and short shots are likely to occur. If it exceeds 30 ° C, solidification of the molded product after molding becomes insufficient and the sintered product may be deformed. The injection temperature is preferably 75 to 95 ° C. If it is less than 75 ° C, the fluidity is insufficient and short shots are likely to occur. If it exceeds 95 ° C, bubbles are generated due to water evaporation in the molded body, and after sintering, Cause the occurrence of voids in the sintered body,
Further, the evaporation of water lowers the fluidity of the kneaded product, and the kneaded product may be clogged in the molding machine, which is not preferable. If the injection molding pressure is less than 30 kg / cm ² , weld will occur and the molding density will be non-uniform, and bending and waviness will occur after sintering, and if it exceeds 70 kg / cm ² , burrs will be generated, which is not preferable. Pressure is 30-70
kg / cm ² is preferred.

In the present invention, the injection-molded molded article is dehydrated and then debindered,
Then, it is sintered. The dehydration treatment varies depending on the amount of water added, but the temperature rising rate up to at least 20 to 100 ° C is 90 ° C.
/ Hr or less is preferable. Temperature rising rate is 90 ° C /
If it exceeds hr, the treated product may crack or crack due to rapid vaporization of water. The water is 100
Most of it evaporates during heating up to ℃

The binder removal treatment is basically unnecessary, but it can be carried out by a known method depending on the amount of agar added to the binder, the presence or absence of a lubricant, etc.
If the temperature is raised at a rate of up to 200 ° C./hour, debinding processing can be performed, and the time required for debinding can be significantly shortened as compared with the case of using a conventional organic binder. In addition, debinding can be performed by heating in the same furnace as in sintering, and sintering can be performed by directly raising the temperature of the debinding, thus shortening the manufacturing process time and downsizing equipment. Will be possible.

Sintering can be carried out subsequent to the binder removal treatment, and the sintering temperature, sintering time, temperature rising rate, cooling conditions after sintering, etc. are appropriately selected according to the alloy composition and the like. It is preferable to carry out the above method. It is most preferable to perform the binder removal and the sintering both in a vacuum atmosphere, but it is also preferable to use a reducing gas or an inert gas as the sintering atmosphere. Temperature rising rate during sintering is 200-400
C / hr is preferred. Also, the sintering temperature is preferably 1200 ° C or higher in order to make the compact compact, and is approximately 1300 ° C.
Is most preferred.

[0016]

According to the present invention, Fe-Ni-Co alloy powder is injection-molded to mold various shaped parts. The kneaded product is prepared by kneading agar which causes sol-gel transformation as a binder and water. The gel strength in the gel state of
It is possible to greatly improve the green strength of the molded body after molding,
Since it is possible to manufacture complicated shaped parts including thick materials, and basically no debinding process is required, it is possible to shorten the manufacturing process time, and further, the pores of the sintered body after sintering,
Reduction of voids can be realized. Furthermore, since the injection molding method according to the present invention contains a large amount of water in the binder, it is possible to relatively reduce the amount of carbon in the binder.

[0017]

【Example】

Example 29Ni-17Co-Fe having an average crystal grain size of 10.2 μm
-Based alloy powder and 30Ni-1 having an average crystal grain size of 9.8 μm
Using two alloy powders of 6Co-Fe alloy powder, 1
After mixing 2% by weight of agar and 0.2% by weight of stearic acid in 0% by weight of water, heating to 90 ° C. with stirring, naturally cooling to 60 ° C., and keeping the temperature as it is.
After adding 08 wt% of sodium tetraborate, the alloy powder was added and further kneaded. Next, the kneaded product is
20 mm at injection temperature 95 ° C and mold temperature 20 ° C (room temperature)
It was molded into a plate of × 20 mm × 5 mm and 20 mm × 20 mm × 15 mm. The obtained molded body was dehydrated, degreased and sintered in a hydrogen atmosphere according to the temperature rising pattern shown in FIG. After injection molding, it took 10 hours to complete the sintering.
The relative density and plate thickness of the obtained sintered body are shown in Table 1 (Sample Nos. 1 to 4).

Comparative Example Using the alloy powder of the above-mentioned example, 5 as a binder
Using an acrylic resin of 3 wt%, an ethylene vinyl acetate copolymer of 3 wt% and a wax of 2 wt%, an injection temperature of 15
After injection molding was performed on a plate having the same dimensions as in the example at 0 ° C. and a mold temperature of 20 ° C. (room temperature), the molded body was heated in the atmosphere at a temperature rising rate of 8 ° C. /
hr, temperature 320 ° C., holding time 3 hours, after debinding, hydrogen atmosphere temperature rising rate 300 ° C./hr, temperature 1300
Sintering was carried out at a temperature of 2 hours for 2 hours. After injection molding, it took 50 hours to complete the sintering. The relative density and plate thickness of the obtained sintered body are shown in Table 1 (Sample Nos. 5 to 8).

[0019]

[Table 1]

[0020]

INDUSTRIAL APPLICABILITY According to the present invention, Fe for sealing by injection molding is used.
In the method of manufacturing a Ni-Co alloy part, by adding agar and water as a binder and performing injection molding, as is apparent from the examples, even a molded body having a sintered density of approximately 12 mm can be obtained. In addition, the degreasing time can be greatly reduced from 43 hours of the conventional binder to 3.5 hours, it can be shortened to about 1/10, and complex shaped parts including thick materials can be manufactured. Since the debinding process is unnecessary, it is possible to significantly reduce the manufacturing time.

[Brief description of drawings]

FIG. 1 is a graph showing a temperature rise pattern of a molded body in an example.

Claims (2)

[Claims] 1. Fe-Ni-Co for sealing by injection molding
Ni-27 to 34 wt.
%, Co12 to 19 wt%, the balance Fe and unavoidable impurities, and agar and water as binders to an alloy powder having an average particle size of 30 μm or less, kneaded, and then injection-molded into a predetermined shape, A method for producing a Fe-Ni-Co based alloy component for sealing, which comprises sintering the compact. 2. The binder is 1 to 4 wt% agar and 5 to water.
Consists of 15 wt% and stearic acid 0.0 as lubricant
5-0.5 wt%, sodium tetraborate 0.01-0.
The method for producing an Fe-Ni-Co based alloy component for sealing according to claim 1, wherein the Fe-Ni-Co based sealing alloy component contains 5 wt%.