JPH093647A - Thermal stress relaxation type coated heat resistant structure part and its production - Google Patents

Abstract

PURPOSE: To provide thermal stress relaxation type coated heat resistant structure parts by relaxing the thermal stress in the heat resistant coating layer in which temp. distribution is formed so that it is higher in percentage in a cross-sectional radial or longitudinal direction and to improve the reliability of a plant and to provide a method thereof. CONSTITUTION: A coating layer 8 of heat resistant material is laminated on the surface of structure parts 6 by forming a columnar crystal structure 8a, a fine crystalline grain structure 8b, or the columnar crystal structure 8a and the fine crystalline grain structure 8b. This heat resistant coating layer 8 has a function of developing fine cracks in a film-thickness direction by the application of thermal stress and relaxing the thermal stress. By this method, the thermal stress relaxation type coated heat resistant structure parts, excellent in heat resistance and thermal shock resistance, can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural part provided with a heat-resistant coating layer and a method for manufacturing the structural part, and more particularly to a hollow cylinder or a solid cylinder having a temperature distribution formed in a radial direction or a longitudinal direction of a cross section. The present invention relates to a thermally stress-relaxed coated heat-resistant structural component that has any one of a hollow disc, a solid disc shape, and an axially symmetric structure, and is subjected to thermal stress, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional stress generation condition in a hollow cylinder or a hollow disk having a temperature distribution formed in a radial direction of a cross section will be described with reference to FIGS. 9 and 10 show a hollow cylinder 1
2 shows the relationship between the fluids 2 and 3 flowing around and the temperature distribution generated in the cross section of the hollow cylinder 1. FIG. 11 shows the cross-sectional thickness direction stress distribution generated in the hollow cylinder when the inner circumference is higher in temperature than the outer circumference, and FIG. 12 shows the cross-section thickness direction stress distribution generated in the hollow disc under the same temperature condition. Show. FIG. 13 shows a cross-section thickness direction stress distribution generated in the hollow cylinder when the outer circumference is higher in temperature than the inner circumference, and FIG. 14 shows a cross-section thickness direction stress distribution generated in the hollow disc under the same temperature condition. Show. FIG.
5 and 16 show an example of a cylinder having a finite length which belongs to the middle of a hollow disk and a hollow cylinder, and shows the temperature and stress distribution in the case of an axisymmetric body having a curvature on the end face. FIG. 17 shows the relationship between thermal stress and strain generated on the inner and outer peripheral sides when the inner peripheral temperature is high and the outer peripheral temperature is low, and FIG. 18 is when the inner peripheral temperature is low.

The symbols in each figure indicate the following contents.
That is, 1 is a cylinder, 2 is a high temperature fluid, 3 is a low temperature fluid, 4
Is the inner peripheral surface, and 5 is the outer peripheral portion of the cylinder.

9 and 10 show the relationship between the fluids 2 and 3 flowing around the hollow cylinder 1 and the temperature distribution generated in the cross section of the hollow cylinder 1. FIG. 9 basically shows conditions when the temperature of the inner peripheral surface 4 of the cylinder is higher than the temperature of the outer peripheral portion 5 of the cylinder. That is, in FIG. 9A, the temperature of the fluid 2 flowing inside the cylinder is higher than that of the fluid 3 flowing in the outer peripheral portion 5 of the cylinder, and as a result, the temperature of the inner peripheral portion of the cylinder is higher than the other portions. As described above, the temperature distribution in the radial direction is shown. FIG. 9B shows the condition when the temperature of the cylinder is initially low and the high-temperature fluid 2 suddenly flows inside the cylinder. After a long period of time, the temperature of the entire cross section becomes constant, but at the beginning of the flow of the fluid, a temperature distribution is formed in the radial direction. FIG. 9C shows the condition when the temperature of the cylinder is high and the low temperature fluid 3 suddenly flows to the outer peripheral portion of the cylinder. Similar to FIG. 9B, after a long time has passed, the entire cross section has a constant temperature, but at the beginning of the flow of the fluid, a temperature distribution is formed in the radial direction.

On the other hand, FIG. 10 shows conditions basically when the temperature of the inner peripheral surface 4 of the cylinder is lower than the temperature of the outer peripheral portion 5 of the cylinder. That is, in FIG. 10A, the temperature of the fluid 3 inside the cylinder is lower than that of the fluid 2 flowing in the outer peripheral portion 5 of the cylinder, and as a result, the temperature of the inner periphery of the cylinder becomes higher than the other portions, as shown in the figure. It shows the temperature distribution in the radial direction.
FIG. 10B shows the condition when the temperature of the cylinder is initially low and the high temperature fluid 2 rapidly flows around the outer circumference of the cylinder. After a long period of time, the entire cross section has a constant temperature, but at the beginning of the fluid flow, a temperature distribution is formed in the radial direction. In FIG. 10 (c), the temperature of the cylinder is initially high, and the low-temperature fluid 3 suddenly appears inside the cylinder.
Is a condition for flowing. Similar to FIG. 10B, after a long time has passed, the entire cross section has a constant temperature, but at the beginning of the flow of the fluid, a temperature distribution is formed in the radial direction.

11 to 14 show stress distributions generated in the cross-section wall thickness when the above-mentioned temperature distribution exists in the hollow cylinder and the hollow disk. 11 and 12 show the elastic stress distributions of the cylinder and the disk, respectively, when the temperature of the inner circumference is high and the temperature distribution is in the thickness direction. It can be seen that both the cylinder and the disk have high temperatures, so that the inner circumference shows compressive stress and the outer circumference shows tensile stress. On the other hand, FIG. 13 and FIG. 14 show elastic stress distributions when the outer peripheral temperature is high. In this case, it can be seen that the inner circumference shows tensile stress and the outer circumference shows compressive stress.

Further, FIG. 15 shows a temperature distribution in the case of an axisymmetric cylinder having a finite length and having a curvature on the end face. Since the portion having the curvature is also affected by the high temperature fluid, the temperature is almost parallel to the shape of the inner surface as shown in the figure. As a result, the generated thermal stress is, as shown in FIG. 16, almost parallel to the shape of the inner surface, and has a compressive stress near the inner surface and a tensile stress near the outer surface.

[0008]

With respect to the thermal stress thus generated, the temperature distribution in the radial direction changes depending on the contacting fluid, and the thermal stress value also changes accordingly. Although the elastic stress values are shown in FIGS. 11 to 14, the larger the temperature distribution in the radial direction, the larger the generated thermal stress. FIG.
FIG. 7 and FIG. 18 show the relationship between the thermal stress strains generated on the inner peripheral side and the outer peripheral side when the inner peripheral temperature is high and the outer peripheral temperature is low, and when the inner peripheral temperature is low and the outer peripheral temperature is high. When the thermal stress is large, the physical strength is low on the high temperature side, so that plastic deformation occurs earlier than on the low temperature side.

As a result, the generated inelastic strain also becomes large. Since the fluid flow is repeated by starting and stopping the plant, the total cyclic strain range becomes larger on the high temperature side than on the low temperature side. The low cycle fatigue strength is also lower in the high temperature atmosphere than in the low temperature. As a result, the life at the higher temperature becomes shorter, thermal fatigue cracks may occur early in repetition, and if the material has low ductility, cracks may occur at one load. Become.

For example, a compression pipe for compressing the gas filled in the pipe by the movement of the piston, a high-pressure air storage tank for storing high-pressure gas which is a driving source of the piston, and a compression pipe are connected to move the piston. A shock wave tube filled with a test gas that is compressed by adiabatic compressed gas, a nozzle that expands the compressed test gas at the end of the shock wave tube to generate a high-speed airflow, and a test section and a dump installed downstream of the nozzle In a free-piston type shock wind tunnel device consisting of a tank, the shock tube end sleeve exposed to the high-speed air flow of the test gas, the end plate of the nozzle part, and the structural parts of the nozzle throat have a long life under operating conditions in the high heat flow rate region. Need to be promoted.

As described above, due to the thermal stress and the repeated thermal stress, a crack may be generated in the structure 1 and the crack may be propagated. Therefore, in a structural part affected by the high temperature fluid, It is necessary to take measures to prevent cracks and improve the reliability of the plant.

That is, in a hollow cylinder, a solid cylinder, a hollow disc, a solid disc shape, and a structure having an axially symmetric structure, the cross section of which has a temperature distribution formed in the radial direction or the longitudinal direction of the cross section. When the temperature distribution becomes extremely large in the radial direction or the longitudinal direction, thermal stress becomes large, and cracks occur, turbulent flow occurs in the hot air flow, and the desired air flow characteristics cannot be obtained, resulting in plant reliability. Have a great influence on.

An object of the present invention is to provide a thermal stress relaxation type coated heat resistant structure part and a manufacturing method for reducing thermal stress even if a temperature distribution is formed in a radial direction or a longitudinal direction of a cross section, and a plant reliability. Is to improve the sex.

[0014]

In order to achieve the above object, the first invention of the present application is a hollow cylinder, a solid cylinder, a hollow disk, a solid disk shape, and an axisymmetric shape in which a temperature distribution is formed. In any of the structures described above, which is subjected to thermal stress, a heat-resistant coating layer is provided on the surface of the structure component having a temperature on the high temperature side, and the heat-resistant coating layer is formed in the film thickness direction. A thermal stress relaxation type characterized by exhibiting a columnar crystal structure, a fine crystal grain structure or a laminated structure of a columnar crystal structure and a fine crystal grain structure, and the heat resistant coating layer causes cracks in the film thickness direction due to the load of thermal stress. It is a coated heat-resistant structure part.

In the second invention of the present application, the heat-resistant coating layer has a columnar structure of tungsten, a columnar structure of rhenium, a columnar structure of niobium, a fine grain structure of tungsten / rhenium alloy, or a columnar structure of tungsten. It is preferable that a coating layer made of at least one of tungsten / rhenium alloy having a fine grain structure, tungsten / niobium alloy, and niobium / rhenium alloy is laminated on at least one coating layer of rhenium and niobium.

In the third invention of the present application, the structural component is made of metal, and the material thereof is preferably Cu, Ni, Mo, Fe. In addition, it is preferable to be made of those alloys.

In the fourth invention of the present application, a diffusion layer containing material components of the structural component and the heat resistant coating layer may be formed at the boundary between the structural component and the heat resistant coating layer.

In the fifth invention of the present application, it is preferable that the heat resistant coating layer has a thickness in the vicinity of a position where the compressive stress generated in the radial direction and the longitudinal direction of the cross section of the structural component becomes zero.

The sixth invention of the present application is any one of a hollow cylinder having a temperature distribution, a solid cylinder, a hollow disc, a solid disc shape, and an axisymmetric structure, and a thermal stress. In a structural part that receives heat, a heat-resistant coating layer is provided on the surface of the structural part having a temperature on the high temperature side, and the heat-resistant coating layer is made of tungsten, rhenium, niobium, or a tungsten / rhenium alloy, a tungsten / niobium alloy, a niobium / rhenium. The alloy is produced by reducing halogen gas of tungsten, rhenium and niobium with hydrogen gas.

In the seventh invention of the present application, the structural part provided with the heat-resistant coating layer is manufactured by subjecting the structural part to heat treatment at 600 ° C. to 2000 ° C. in vacuum or in an inert gas atmosphere. is there.

The eighth invention of the present application is connected to a compression tube for compressing the gas filled in the tube by the movement of the piston, a high-pressure air storage tank for storing high-pressure gas that is a drive source of the piston, and a compression tube. , A shock wave tube filled with a test gas compressed by adiabatic compression by the movement of the piston, a nozzle for expanding the compressed test gas at the end of the shock wave tube to generate a high-speed airflow, and a nozzle installed downstream of the nozzle In a free-piston type impact wind tunnel device consisting of a test section and a dump tank, a heat-resistant coating layer is provided on the sleeve of the end of the shock tube and the end plate of the nozzle and the surface of the nozzle throat exposed to the high-speed air flow of the test gas. The heat-resistant coating layer has a columnar crystal structure, a fine crystal grain structure or a laminated set of a columnar crystal structure and a fine crystal grain structure in the film thickness direction. The exhibits, heat-resistant coating layer intended to produce a fine cracks in the film thickness direction by the load of the thermal stress,
On the coating layer of tungsten having a columnar structure, rhenium having a columnar structure, niobium having a columnar structure, tungsten / rhenium alloy having a fine grain structure, or at least one coating layer of tungsten, rhenium, and niobium having the columnar structure. A free piston type impact wind tunnel device having a structure in which a coating layer made of at least one of a tungsten / rhenium alloy having a fine grain structure, a tungsten / niobium alloy, and a niobium / rhenium alloy is laminated.

[0022]

The structure and operation of the present invention will be described.

In the present invention, a heat-resistant coating layer made of a high melting point material having a function of relaxing thermal stress is formed on the surface of the structural component. The thickness of the coating layer is set to a region where the compressive stress generated by the generation of thermal stress becomes zero, so that damage such as peeling due to concentration of stress at the boundary portion between the coating layer and the structural component can be prevented.

The heat-resistant coating layer relaxes by generating fine cracks in the film thickness direction rather than the load of thermal stress. Therefore, the structure of the coating layer has a columnar crystal structure or a fine crystal grain structure in the film thickness direction, or a laminated structure of a columnar crystal structure and a fine crystal grain structure.

The heat resistance is ensured by using a high melting point material. There are ceramics, intermetallic compounds, refractory metals, etc., but refractory metals that are excellent in toughness at high temperatures are desirable. That is, when a large thermal stress is generated due to thermal shock or the like, the brittle material such as ceramics may be broken and damaged. As refractory metals, materials with high strength in the high temperature range are tungsten, rhenium,
Niobium, tungsten / rhenium alloy, tungsten / niobium alloy, and niobium / rhenium alloy are preferable.

As a method for forming this as a coating layer, a chemical vapor deposition method (CVD: Chemi) capable of obtaining a highly pure and dense coating film is obtained.
cai Vaper Deposition) is good. The treatment is performed by heating the surface of the base material, which is a structural component heated and held, with a source gas of tungsten, rhenium or niobium halide gas (WF).
₆ , ReF ₆ , NbF ₅ ) and hydrogen gas can be supplied to carry out a reduction reaction. The substrate temperature during coating is, for example, 250 to 600 ° C. in the case of tungsten / rhenium alloy.
The temperature range of 400 to 500 ° C. is optimum for obtaining a uniform fine structure with a particularly high film formation rate. When the substrate temperature is 200 ° C. or lower, the formed film has a non-uniform form. Further, when the substrate temperature is 600 ° C. or higher, the content of the additional element rhenium decreases, and a fine structure cannot be obtained. The CVD pressure is preferably close to normal pressure in order to increase the film formation rate. Also,
The amount of Re contained in the microstructured W-Re alloy is 2.5-
It is preferably 26 wt% from the viewpoint of forming a fine structure.

By satisfying the respective manufacturing conditions, the tungsten, rhenium or niobium coating layer has a columnar crystal structure, and the tungsten / rhenium alloy, the tungsten / niobium alloy and the niobium / rhenium alloy have a fine crystal grain structure. . Here, the columnar crystal structure means a crystal grain size of about 0.1 to 10.0 μm as coated. This columnar crystal structure causes fine cracks in the film thickness direction due to the load of thermal stress. This serves to relieve stress. The fine crystal grain structure means a crystal grain size of about 0.2 to 0.7 μm as coated. The material forged and drawn by ordinary powder sintering grows at a temperature of 1300 to 1500 ° C. to have a crystal grain size of about 50 to 100 μm and becomes brittle, whereas, for example, tungsten of the coating layer of the present invention is used. In the / rhenium alloy, the fine grain structure hardly changes from 1300 to 1500 ° C. Hotter 16
Crystal growth is observed at a temperature of 00 to 2000 ° C., but even in that case, the crystal grain size is as small as 10 μm or less, and there is a characteristic that it is difficult to grow even when heated to a high temperature. In the case of a structure having a layered structure of a columnar crystal structure and a fine crystal grain structure, the columnar crystal structure causes fine cracks in the film thickness direction rather than the load of thermal stress, thereby relaxing the stress. Since the fine crystal grain structure is hard to grow even when heated to a high temperature, it has an effect of suppressing the growth of cracks.

Therefore, the tungsten /
Rhenium alloys, tungsten / niobium alloys, and niobium / rhenium alloys are exposed to high heat flux conditions,
Even when it is heated to a high temperature of 00 ° C and subjected to thermal stress, it effectively prevents the deterioration of heat resistance and strength and improves performance, making it a heat-resistant coated component that meets the needs of high loads. Become.

These functions are based on the fact that the base material is Cu, Ni, M.
The same applies to o, Fe, and alloys thereof. For example, Cu, which has good thermal conductivity, with emphasis on thermal conductivity rather than heat resistance
Alternatively, a heat resistant coating layer may be formed by CVD using a Cu alloy or the like as a base material. However, since the heat-resistant coated parts are made of different materials depending on the intended use, it is necessary to devise a pretreatment for coating, formation of an intermediate layer, and further post-treatment depending on the material. Is not limited.

With the above structure, Cu, Ni, Mo, F
A heat stress relaxation type heat resistant coating layer having excellent heat resistance, adhesion and durability is obtained on a base material made of a metal such as e and alloys thereof, and a heat stress relaxation type coated heat resistant structure part made of the same is obtained. can get.

Further, the sleeve at the end of the shock wave tube exposed to the high-speed air flow of the test gas of the free-piston type shock wind tunnel device, the end plate of the nozzle portion, and the nozzle throat are made to be thermal stress relaxation type coated heat-resistant structural parts. As a result, the life can be extended under the operating conditions in the high heat flow rate region.

[0032]

The present invention will be described below with reference to examples.

(Embodiment 1) In this embodiment, a free piston type impact wind tunnel device for supplying an air flow having a velocity of several kilometers per second is applied to a structural part exposed to a high-speed flow of a high-temperature high-pressure test gas. Here is an example.

In order to realize the aerodynamic heating state that the space shuttle receives when it re-enters the atmosphere, it is necessary to generate an airflow at a speed of several km per second. In order to generate an air flow at a speed of several kilometers per second, it is necessary to create a high enthalpy state of about 10,000 degrees and 1,000 atmospheric pressure as a storage state of a wind tunnel. This kind of high temperature and high pressure state is achieved by utilizing shock waves. There is a shock tube as an experimental facility that generates a shock wave. The shock wave tube compresses the low pressure test gas by the high pressure driving gas, compresses the low pressure gas by the shock wave generated when the high pressure gas expands to the low pressure gas side, and further the shock wave tube end side of the low pressure gas. Therefore, when this shock wave is reflected, a high temperature and high pressure state occurs. The increase in pressure and temperature at this time is determined by the strength of the shock wave propagating in the tube. The strength of the shock wave depends on the pressure ratio and the sound velocity ratio of the gas on the high pressure side and the gas on the low pressure side. If the pressure ratio is the same, it is easier to generate a high enthalpy state by increasing the sound velocity ratio. For this purpose, helium is usually used as the driving gas. In a free-piston type wind tunnel, helium is brought into a high-temperature and high-pressure state by the compression action of a piston, and this is used as a driving gas to obtain a test gas with a high enthalpy state at the end of the shock tube.

FIG. 4 is a sectional view showing an outline of an example of a free piston type wind tunnel device. FIG. 5 shows a detailed structure of the vicinity of the second diaphragm of FIG. 4, and in this embodiment, this nozzle throat is composed of the thermal stress relaxation type coated heat resistant structural member of the present invention. In FIG. 4, a compression tube 10 for compressing helium gas by a piston 12, a shock wave tube 16 for compressing a test gas (air gas in this embodiment) by the compressed helium, and a high pressure generated at the end of the shock wave tube. The test gas in the enthalpy state is expanded and the speed is several km per second.
The supersonic nozzle 17 for generating the air flow of the following speed, the test model 25 is installed and the test section 24 in which the test state is observed and the dump tank 26 installed downstream of the test section are configured. A first diaphragm 19 for partitioning the helium gas and the test gas is installed between the compression tube and the shock wave tube, and a second diaphragm 20 is installed between the shock wave tube and the supersonic nozzle. The second diaphragm is held by the sleeve 21 at the end of the shock tube, the end plate 22 and the nozzle throat 23 when viewed in detail in FIG. A high-pressure air storage tank 11 for supplying high-pressure air for driving the piston 12 is provided on the compression tube 10 on the side opposite to the connection side of the shock wave tube 16.

The dump tank 26 is evacuated, the test gas in the shock wave tube and the helium in the compression tube are set to a predetermined pressure, and then high pressure air is supplied from the high pressure air tank to the back surface of the piston to drive the piston. The helium in the compression tube is compressed by the piston drive and becomes a high temperature and high pressure state. When the pressure of helium reaches the burst pressure of the first diaphragm,
The high temperature and high pressure helium gas passes through the first diaphragm and flows into the compression tube to compress the test gas. The high temperature and high pressure test gas passes through the second diaphragm and is expanded by the ultrasonic nozzle to generate a high speed flow.

At this time, the structural parts near the second diaphragm are
Exposed to a high-speed stream of high-temperature, high-pressure test gas. Therefore, the surfaces exposed to the high-speed flow of these structural parts are subjected to a high-energy heat flow rate, resulting in large thermal stress.

In this embodiment, a heat-stress-releasing coated heat-resistant structural component having a heat-resistant coating layer on the surface of the nozzle throat is used. That is, the base material of the nozzle throat was made of Mo alloy (containing Ti and Zr), and the heat resistant coating layer was provided on the surface thereof. Table 1 shows the specifications of the heat resistant coating layer.

[0039]

[Table 1]

The material of the heat resistant coating layer is 1. tungsten,
2. Rhenium, 3. Tungsten-rhenium, 4. There are four kinds of laminated tungsten and tungsten-rhenium, and there are two kinds of thickness of about 0.5 mm and 1.3 mm, and CV
Coated by method D. In CVD, the substrate is first heated to 450 ° C. in a hydrogen gas atmosphere, and then WF ₆ or ReF ₆ ,
Alternatively, a mixed gas containing WF ₆ and ReF ₆ was introduced onto the base material. Approximately 10 for uniform coating during processing
The substrate was spun at rpm. After forming the heat resistant coating layer while rotating, vacuum heat treatment was performed at 1100 ° C. for 1 hour. This heat treatment may be performed in an inert gas atmosphere. At this time, the grain size of the fine grain structure was 0.9 to 4.5 μm. Next, this nozzle throat was incorporated into a free piston type impact wind tunnel device, three heat flow rates were set as operating conditions, and an actual load test was repeated three times. The evaluation was performed by observing the appearance after the test, observing the surface with an electron microscope, and observing the cut cross section with an optical microscope. Table 1 shows a summary of the test results. As a result, in the nozzle throat of the thermal stress relaxation type coated heat-resistant structure part of the present invention, a large crack was generated when the heat flow rate was increased in the case of only the columnar structure of tungsten or rhenium, but the fine grain structure The tungsten-rhenium or the tungsten-tungsten-rhenium laminate has a surface roughness that does not adversely affect the air flow performance even though fine cracks are randomly formed on the surface at a high heat flow rate, and a crack width size. It was Therefore, the test in the high heat flux region was possible. Even with this coating layer, peeling of the coating layer was observed when the thickness was thin. In the case of W, when the stored state was 25 MJ / kg, the layers separated with a thickness of 0.5 and 1.3 mm, but at 20 MJ / kg, the thickness was 1.3 m.
It did not peel off at m. In the case of W / Re, the stored state 2
At 0.25 MJ / kg, it peeled at a thickness of 0.5 mm and did not peel at a thickness of 1.3 mm. Also for the laminate of W and W / Re, when the stored state is 20, 25 MJ / kg, peeling with thickness W (0.2 mm) and W-Re (0.3 mm), thickness (0.6 mm ) And W-Re (0.7 mm), no peeling occurred. Thus, it was found that when the thickness was 20 and 25 MJ / kg, peeling did not occur at a thickness of 0.6 mm or more. This is because the interface between the base material, which is the structural component, and the coating layer was within the range where the thermal stress was generated due to the rapid temperature gradient, so that the large stress could not be endured. As conventional examples, comparative Mo materials, Mo alloys containing Ti and Zr), W alloys (C
u-W, Ni-W) was not damaged in the test at a low heat flow rate, but when the heat flow rate became large, cracks were observed in the Mo material or Mo alloy in the circumferential direction and the oblique direction of the air flow direction. It grew with the increase in the number of tests. Further, the cross-sectional structure was observed because it exhibited a recrystallized structure in which crystal grains were coarsened in a region of about 1 mm from the surface. Therefore, it was found that this region was exposed to the condition of being heated to the temperature range of several thousand and several hundred degrees Celsius where the Mo material was recrystallized. In appearance, the W alloy was observed to have cracks and a rough surface morphology. As for the cross-sectional structure, the composition parts of Cu and Ni having a low melting point were melted and worn.

The nozzle throat made of these conventional materials causes turbulence in the air flow due to the presence of large cracks or an increase in surface roughness. For this reason, the subsequent operation cannot be performed, and the test in the high heat flux region cannot be performed.

As described above, the nozzle throat of the thermal stress relaxation type coated heat resistant structure part of the present invention has excellent characteristics as compared with the parts made of the conventional materials even under the operating conditions in the high heat flux region. It improves the performance of the wind tunnel and the reliability of the plant.

(Embodiment 2) FIG. 7 shows the details of the sleeve 21 at the end of the shock tube of FIGS. 4 and 5. In this embodiment, this sleeve is a thermal stress relaxation type heat-resistant structure of the present invention. It consists of parts. The base material of the sleeve is a nickel-chromium-iron alloy (Inconel), and the inner peripheral surface of FIG.
The heat-resistant coating layer was provided. The heat-resistant coating layer was tungsten-rhenium, and its thickness was about 1.2 mm, which was deeper than the range where compressive stress was generated. Using this sleeve, as in Example 1, incorporated into a free piston type impact wind tunnel device,
Enthalpy value of 25 MJ / kg as operating condition is 3
An actual load test was performed repeatedly. As a result, the surface roughness was such that fine cracks were randomly formed on the surface, but the airflow performance was not adversely affected, and the size of the width of the cracks. Therefore, the test in the high heat flux region was possible.

As described above, the sleeve of the heat-stress-releasing type coated heat-resistant structure part of the present invention has excellent characteristics compared with parts made of conventional materials even under operating conditions in a high heat flow rate region, and the sleeve of the wind tunnel It improves performance and reliability of the plant.

(Embodiment 3) FIG. 8 shows the details of the end plate of FIGS. 4 and 5. In this embodiment, the side surface of the end plate of the shock tube is a thermal stress relaxation type heat resistant structure of the present invention. It consists of body parts. The base material of the end plate was Cu, and the heat-resistant coating layer of FIG. 1 was provided on the side surface of the end of the shock tube. The heat-resistant coating layer was a stack of tungsten and tungsten-rhenium, and the thickness thereof was deeper than the range in which compressive stress was generated, and was about 0.6 mm each.
Using this end plate, it was incorporated into a free piston type impact wind tunnel apparatus in the same manner as in Example 1, and an actual load test was repeated three times with an enthalpy value of 25 MJ / kg as an operating condition. As a result, the surface roughness was such that fine cracks were randomly formed on the surface, but the airflow performance was not adversely affected, and the size of the width of the cracks. Therefore,
It was possible to test the high heat flux region.

As described above, the end plate of the thermal stress relaxation type coated heat-resistant structure part of the present invention has excellent characteristics as compared with the part made of the conventional material even under the operating condition in the high heat flow rate region, and the wind tunnel Performance and plant reliability.

[0047]

EFFECT OF THE INVENTION The effect that the thermal stress of the structural component in which the temperature distribution is formed can be reduced is produced. Further, it is possible to provide a thermal stress relaxation type coated heat-resistant structure part capable of reducing thermal stress and a method for manufacturing the same.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermal stress relaxation type coated heat resistant structure part of the present invention.

FIG. 2 is a cross-sectional view of a thermal stress relaxation type coated heat resistant structure part of the present invention.

FIG. 3 is a cross-sectional view of a thermal stress relaxation type coated heat resistant structure part of the present invention.

FIG. 4 is a sectional view schematically showing an example of a free piston type wind tunnel device.

5 is a partially enlarged cross-sectional view of the vicinity of the second diaphragm of FIG.

6 is a partial enlarged cross-sectional view of the nozzle throat of FIG.

7 is a partial enlarged view of a sleeve at the end of the shock tube of FIG.

8 is a partially enlarged view of the end plate of FIG.

FIG. 9 is a diagram for explaining a situation where a temperature distribution occurs in the radial direction of the hollow cylinder (when the inner circumference is hot).

FIG. 10 is a diagram for explaining a situation where a temperature distribution occurs in the radial direction of a hollow cylinder (when the outer circumference is hot).

FIG. 11 is a characteristic diagram for explaining a stress distribution in the cross-section thickness direction (when the inner circumference is at a high temperature) generated in the hollow cylinder.

FIG. 12 is a characteristic diagram illustrating a stress distribution in the thickness direction of a cross section (when the inner circumference is at a high temperature) generated in a hollow disc.

FIG. 13 is a characteristic diagram illustrating a stress distribution in the cross-section thickness direction (when the outer circumference is at a high temperature) that occurs in the hollow cylinder.

FIG. 14 is a characteristic diagram illustrating a stress distribution in the thickness direction of a cross section (when the outer circumference is at a high temperature) generated in a hollow disc.

FIG. 15 is a diagram illustrating a temperature distribution in the case of an axisymmetric hollow cylinder having an end surface having a curvature.

FIG. 16 is a diagram illustrating a stress distribution in the case of an axisymmetric hollow cylinder having an end surface having a curvature.

FIG. 17 is a diagram for explaining the relationship between the thermal stress and strain of the inner circumference when the inner circumference is high temperature and the outer circumference is low temperature.

FIG. 18 is a diagram for explaining the relationship between the thermal stress and strain of the outer circumference in the case where the inner circumference temperature is low and the outer circumference temperature is low.

[Explanation of symbols]

1 ... Cylinder, 2 ... High temperature fluid, 3 ... Low temperature fluid, 4 ... Inner peripheral surface, 5 ... Cylinder outer peripheral portion, 6 ... Substrate, 7 ... Boundary layer, 8 ... Heat resistant coating layer, 8a ... Fine columnar crystal structure, 8b ... fine crystal grain structure, 10 ... compression tube, 11 ... high pressure air storage tank, 12 ... piston, 13 ... decompression exhaust system connection pipe, 14 ... high pressure air supply pipe, 15 ... atmospheric exhaust pipe, 16 ... shock wave tube, 17 ... super Sonic nozzle, 18 ... Inertial mass, 19 ... First diaphragm, 20 ... Second diaphragm, 21 ... Sleeve, 22 ... End plate, 23 ...
Nozzle throat, 24 ... Test section, 25 ... Test model, 26 ... Dump tank.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiho Kojima 7-1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Noboru Baba 7-chome, Omika-cho, Hitachi-shi, Ibaraki Hitachi, Ltd. Hitachi Research Laboratory, No. 1 (72) Inventor, Tsunehiko Takasagi, 1-1, Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi Ltd., Hitachi, Ltd. (72) Hiroyuki Itami, Hitachi City, Ibaraki Prefecture 3-1, 1-1 Kochimachi Hitachi Ltd. Hitachi factory (72) Inventor Susumu Nakano 502 Jintamachi, Tsuchiura-shi, Ibaraki Prefecture Hiritsu Works Co., Ltd. Mechanical Research Laboratory (72) Inventor Noriaki Matsuda Hitachi-shi, Ibaraki Prefecture 3-2, Sachimachi Hitachi Hitachi Engineering Co., Ltd.

Claims (9)

[Claims] 1. A structure having any one of a hollow cylinder, a solid cylinder, a hollow disc, and a solid disc-shaped axisymmetric structure in which a temperature distribution is formed and which is subjected to thermal stress. In the component, a heat-resistant coating layer is provided on the surface of the structural component having a temperature on the high temperature side, and the heat-resistant coating layer has a columnar crystal structure, a fine crystal structure or a lamination of a columnar crystal structure and a fine crystal grain structure in the film thickness direction. A thermal stress relaxation type coated heat-resistant structural part characterized in that the heat-resistant coating layer exhibits a texture and cracks are generated in the film thickness direction due to the load of thermal stress. 2. The heat-resistant coating layer comprises a columnar structure of tungsten, a columnar structure of rhenium, a columnar structure of niobium, a fine grain structure of tungsten / rhenium alloy, or a columnar structure of tungsten. A coating layer made of at least one of tungsten / rhenium alloy, tungsten ten / niobium alloy, and niobium / rhenium alloy having a fine grain structure is laminated on a coating layer made of at least one of tungsten, rhenium, and niobium. The thermal stress relaxation type coated heat-resistant structure part according to claim 1. 3. The structural component provided with the coating layer is made of metal, and the metal is made of at least one of Cu, Ni, Mo and Fe or an alloy containing at least one of Cu, Ni, Mo and Fe. The thermal stress relaxation type coated heat-resistant structure part according to claim 1, wherein 4. A diffusion layer containing a material component of the structural component and the heat resistant coating layer is formed at a boundary portion between the structural component and the heat resistant coating layer.
The heat-stress-releasing coated heat-resistant structure part according to. 5. The heat-resistant coating layer has a thickness near a position where a compressive stress generated in a radial direction or a longitudinal direction of a cross section of the structural part becomes zero. Thermal stress relaxation type coated heat resistant structure parts. 6. A structure having any one of a hollow cylinder, a solid cylinder, a hollow disk, and a solid disk-shaped axisymmetric structure in which a temperature distribution is formed and which is subjected to thermal stress. In the method of manufacturing a component, a heat-resistant coating layer is provided on the surface of a structure component having a temperature on the high temperature side, and the heat-resistant coating layer is made of tungsten, rhenium, niobium, a tungsten / rhenium alloy,
One of the tungsten / rheobium alloy and the niobium / rhenium alloy is coated by reducing the halogen gas of tungsten, rhenium or niobium with hydrogen gas, and a method for producing a heat-stress relaxing coated heat-resistant structural component. . 7. The thermal stress relaxation type according to claim 6, wherein the structural component is subjected to a heat treatment of heating and holding it in a transient range of 600 ° C. to 2000 ° C. in a vacuum or an inert gas atmosphere. A method for manufacturing a coated heat-resistant structure part. 8. A compression pipe for compressing gas filled in the pipe by movement of the piston, a high-pressure air storage tank for storing high-pressure gas that is a driving source of the piston, and a movement of the piston connected to the compression pipe. A shock tube filled with a test gas that is compressed by adiabatic compressed gas, a nozzle that expands the compressed test gas at the end of the shock tube to generate a high-speed airflow, and a test section and a dump installed downstream of the nozzle. In a free-piston type impact wind tunnel device having a tank, a heat-resistant coating layer is provided on the surface of the sleeve at the end of the shock tube and the end plate of the nozzle and the surface of the nozzle throat exposed to the high-speed air flow of the test gas. The coating layer exhibits a columnar crystal structure, a fine crystal structure or a laminated structure of a columnar crystal structure and a fine crystal grain structure in the film thickness direction, and Layer free-piston type shock tunnel and wherein the resulting cracks in the film thickness direction by the load of the thermal stress. 9. The heat-resistant coating layer of the sleeve, the end plate of the nozzle portion, and the nozzle throat is composed of tungsten having a columnar crystal structure, rhenium having a columnar crystal structure, niobium having a columnar crystal structure, and fine crystal grain structure. Tungsten / rhenium alloy, or at least one or more of tungsten / rhenium alloy, tungsten / niobium alloy, and niobium / rhenium alloy having a fine crystal structure on one or more coating layers of tungsten, rhenium, and niobium having the columnar crystal structure 9. The free-piston type impact wind tunnel device according to claim 8, wherein the coating layer is formed by laminating the following coating layers.