JPH09143667A - Production of high temperature member made of rhenium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a high temp. member made of Re, capable of manufacturing a high quality, high temp. Re member suitable for various combustors, high temp. nozzles, etc., in a relatively short time at a low cost and also capable of facilitating the manufacture of large-size structures. SOLUTION: First, an Re or Re alloy film 2 is formed on the surface of a mandrel 1, having a shape fitted to the internal surface of the high temp. member to be produced, or on the surface of a thermal stress buffer layer formed on the mandrel, by thermal spraying. Then, the mandrel 1 or the mandrel 1 and the thermal stress buffer layer are removed, and the resultant member made of Re or Re alloy is subjected to heat treatment for improving strength characteristic.

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 a high temperature member made of Re suitable for various combustors and high temperature nozzles.

[0002]

2. Description of the Related Art High temperature shock resistance (high temperature strength, high temperature ductility) is required for high temperature members used in various combustors such as rocket engine combustors and high temperature nozzles. Re, which has excellent impact properties, is used. Conventionally, these Re-made high-temperature members are generally manufactured by the CVD method (chemical vapor deposition method). It will be described with reference to FIG. 3, which is an explanatory diagram schematically showing the outline of the process of manufacturing the Re combustor by the CVD method. First, a mandrel 1 made of Mo alloy or the like having a shape matching the shape of the inside of the combustor is prepared. Then CV on the surface of mandrel 1
The CVD method Re film 4 is formed by the D method. afterwards,
A combustor made of Re is obtained by dissolving and removing the mandrel 1 with a chemical.

[0003]

According to the above method,
Although it is possible to obtain a high temperature member made of Re having excellent thermal shock resistance, there are the following problems. That is, (1) the deposition rate in the CVD method is several tens per hour.
It is about several hundred μm, and several days to several tens days are required to form a high temperature member having a wall thickness of several mm, which causes a high cost. (2) Generally, the CVD reaction chamber is small, and a large structure (for example, a combustion chamber having a diameter of 70 mm and a length of about 130 mm) cannot be placed in the CVD reaction chamber, which makes it difficult to manufacture the large structure.

The present invention solves the above-mentioned problems in the prior art, makes it possible to manufacture a high-quality Re-made high-temperature member in a relatively short time, at low cost, and to easily manufacture a large structure.
It is intended to provide a method for manufacturing a high temperature member made of e.

[0005]

Means for Solving the Problems The present invention comprises (1) removing a mandrel after forming a film of Re or Re alloy on the surface of a mandrel having a shape adapted to the inner surface of a high temperature member to be manufactured by a thermal spraying method, A method for producing a Re-made high temperature member, characterized by subjecting the obtained Re or Re alloy member to a heat treatment for improving strength characteristics, and (2) a surface having a shape adapted to the inner surface of the produced high-temperature member. R on the surface of the mandrel with the thermal stress buffer layer formed by thermal spraying
High temperature made of Re, characterized in that after forming a film of e or Re alloy, the mandrel including the thermal stress buffer layer is removed, and the resulting member made of Re or Re alloy is subjected to heat treatment for improving strength characteristics. It is a manufacturing method of a member.

The method for producing a Re-made high temperature member of the present invention is particularly suitable as a method for producing various combustors such as a rocket engine combustor.

As the material of the Re coating in the method of the present invention, in addition to pure Re metal, a Re-Mo alloy containing up to 60% by weight of Mo or an up to 60% by weight of W is added.
Re alloys such as -W alloys can be used.

The material of the mandrel must be a metal having a low coefficient of thermal expansion and capable of being eluted with a chemical such as hydrochloric acid. For example, Fe-30 to 40 wt.
% Ni, Fe-30 to 40 wt% Ni-5 to 10 wt%
Co, pure Mo, etc. can be used.

In the method of the present invention, R
e The film is formed, so the film formation rate is 1 per hour.
The thickness is up to 5 mm, and a member having a thickness of several mm can be formed in about 1 hour. Also, diameter 200 mm, length 300 m
It is also possible to manufacture a large structure of about m.

As the thermal spraying method, the plasma thermal spraying method is preferable because it is necessary to melt Re having a high melting point. Further, since the incorporation of impurities into the material greatly deteriorates the material characteristics (ductility), the plasma spraying method is performed in an inert atmosphere. Thermal spraying is preferred. Therefore, the low pressure plasma spraying method (LPPS) is optimal as the spraying method in the method of the present invention.

In general, thermal spray coatings often have defects therein and do not always exhibit sufficient strength characteristics. Also,
Due to the layered structure, delamination is likely to occur. This is also one reason why the thermal spraying method has not been put to practical use in the manufacture of Re high temperature members. In the present invention, after forming a film by thermal spraying, by performing an appropriate heat treatment, recrystallization is caused in the film to homogenize the structure and improve its strength characteristics (tensile strength, elongation, etc.). Is characterized by.

The optimum conditions for the heat treatment vary depending on the material and thickness of the film, but generally the temperature should be maintained at 1300 to 1800 ° C. for 0.5 to 6 hours. Also, if heat treatment is performed before removing the mandrel, a reaction may occur between the material of the mandrel and the thermal spray material, or there may be a problem that cracks may occur due to the difference in thermal expansion between the two,
The heat treatment is preferably performed after removing the mandrel.

When manufacturing a high temperature member having a wall thickness (for example, 1.5 mm or more), cracks may occur in the coating due to thermal stress during low temperature plasma spraying. In order to prevent this, it is effective to provide a thermal stress buffer layer between the mandrel made of a metal having a low coefficient of thermal expansion and the Re thermal spray coating.

The material for forming the thermal stress relaxation layer needs to be a soft metal, such as Cu or Ni.
Etc. can be used. The thickness of this thermal stress relaxation layer is 0.5 to
It may be about 3 mm.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the method of the present invention will be described with reference to the drawings showing the embodiments thereof. FIG. 1 is an explanatory view schematically showing a process of manufacturing a Re-made combustor by the method of the invention (1). In this embodiment, first, a mandrel 1 made of a low thermal expansion alloy having a shape matching the shape of the inner surface of the combustor is prepared. After blasting the surface of the mandrel 1, a Re sprayed coating 2 is formed on the surface by low pressure plasma spraying. Next, the mandrel 1 is eluted with a chemical such as hydrochloric acid, and the Re sprayed coating 2
Get a structure consisting of only. The obtained structure is subjected to heat treatment at, for example, 1400 ° C. for about 2 hours in a vacuum furnace or a hydrogen furnace to eliminate internal defects and to precipitate fine crystals by recrystallization to increase the material strength and ductility. Turn into.

This method is suitable for manufacturing a thin-walled Re combustor (for example, a wall thickness of about 1 mm). When the internal pressure during use is relatively low, a Re-combustor that is as light as possible is used. It can be supplied at low cost.

FIG. 2 shows Re by the method of the invention of (2) above.
It is explanatory drawing which shows typically the process of manufacturing the combustor made from. In this embodiment, first, a mandrel 1 made of a low thermal expansion alloy is prepared. After blasting the surface of the mandrel 1, a Cu coating 3 as a thermal stress buffer layer is formed on the surface by low pressure plasma spraying. Next, if necessary, the surface of the Cu coating 3 is cut and finished according to the shape of the combustor by machining, and then the Re sprayed coating 2 is formed on the surface by low pressure plasma spraying. Next, the mandrel 1 and the Cu coating 3 are eluted with a chemical such as hydrochloric acid to obtain a structure consisting only of the Re sprayed coating 2. As in the case of the embodiment shown in FIG. 1, the obtained structure is subjected to heat treatment in a vacuum furnace or a hydrogen furnace at, for example, 1400 ° C. for about 2 hours to eliminate internal defects and precipitate fine crystals by recrystallization. To increase the strength and ductility of the material.

In the method of this aspect, since the stress relaxation layer is provided between the mandrel and the Re sprayed coating, cracks do not occur even in a thick wall structure, so the wall thickness can be up to about 5 mm. It is possible to supply a highly efficient combustor that can be used at high internal pressure at low cost.

[0019]

EXAMPLES Next, the method of the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples. By the method of the present invention, the shape shown in FIGS.
m, throat diameter 26 mm, skirt diameter 71 m
The combustor of m) was produced. The manufacturing method is as follows. A thermal stress relaxation layer of Cu having a thickness of 1 mm was formed on a Fe-36 wt% Ni mandrel by low temperature plasma spraying. Then, a 2 mm-thick pure Re film was formed on this thermal stress relaxation layer by low temperature plasma spraying, and then the mandrel and the Cu layer were eluted and removed using hydrochloric acid to obtain a structure made of Re. . This structure was held at 1400 ° C. for 2 hours for heat treatment to obtain a Re combustor. The results of measuring the strength and ductility of the product before and after the heat treatment are shown in Table 1, and the characteristics are improved by the heat treatment, and the high strength,
It can be seen that a Re-combustor with high ductility is obtained.

[0020]

[Table 1]

[0021]

According to the method of the present invention, the following effects can be obtained. (1) Since the film formation rate is high, it is possible to manufacture at a low cost, and it is easy to manufacture a large structure. (2) The structure can be controlled by heat treatment after thermal spraying, and a high-quality structure having high strength and high ductility can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a manufacturing process of a Re-made high temperature member according to one embodiment of the present invention.

FIG. 2 is an explanatory view schematically showing a manufacturing process of a Re-made high temperature member according to another embodiment of the present invention.

FIG. 3 is an explanatory view schematically showing a manufacturing process of a Re-made high temperature member by a conventional CVD method.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Riki Fujiwara 10 Oemachi, Minato-ku, Nagoya, Aichi Mitsubishi Heavy Industries, Ltd. Nagoya Aerospace Systems Works

Claims (3)

[Claims] 1. A member made of Re or Re alloy obtained by forming a coating film of Re or Re alloy on the surface of a mandrel having a shape adapted to the inner surface of a high temperature member to be manufactured and then removing the mandrel. A method of manufacturing a high temperature member made of Re, which comprises performing a heat treatment for improving strength characteristics. 2. A thermal stress buffer layer after forming a film of Re or Re alloy by a thermal spraying method on the surface of a mandrel having a thermal stress buffer layer formed on the surface of a high temperature member to be manufactured. A method for producing a high temperature member made of Re, characterized in that the mandrel containing is removed, and the obtained member made of Re or Re alloy is subjected to heat treatment for improving strength characteristics. 3. The method for producing a high temperature member made of Re according to claim 1, wherein the high temperature member made of Re is a combustor.