JPH10251785A - Oxide dispersion strengthened type alloy, its production and high temperature parts for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart sufficient high temp. strength and excellent workability to an alloy as the material for high temp. parts by dispersing a specified amt. of Y2 O3 particles into the mother phases of an Ni base alloy contg. specified amounts of Cr, Co, Mo, W, Fe, Mn, Si and C. SOLUTION: The compsn. of an Ni base mother phase alloy is composed of 18.0 to 25.0% Cr, >0 to 3.0% Co, 7.0 to 12.0% Mo+W, 15.0 to 22.0% Fe, >0 to 1.0% Mn, >0 to 1.0% Si, >0 to 0.5% C, and the balance Ni with inevitable impurities. Into this Ni base mother phase alloy, 0.01 to 10.0% Y2 O3 particles are dispersed. Furthermore, the content of Mo in the mother phase alloy is preferably regulated to 8 to 10% and the content of W to 0.2 to 1.0%. Moreover, the Y2 O3 particles are dispersed into the mother phases of the Ni base alloy in a state in which the size distribution in regulated to 0.01 to 5μm. Furthermore, the content of oxygen in the mother phases in the Ni base alloy is preferably regulated to <=600ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide dispersion-strengthened alloy which is excellent in high-temperature strength and workability and is suitable for high-temperature gas turbine component materials and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, in the field of gas turbines for power generation, research and development for increasing the efficiency of gas turbines has been actively conducted from the viewpoint of effective utilization of energy resources. In a gas turbine, since the power generation efficiency increases as the temperature of the gas at the outlet of the combustor increases, the temperature at the inlet of the gas turbine is increased. However, the environment for the materials for high-temperature components constituting a gas turbine is extremely severe, and there is a problem of a decrease in strength at high temperatures, remarkable high-temperature corrosion and high-temperature oxidation.

[0003] Recently, as a heat-resistant material which can be used even in a severe environment accompanying the high temperature of the gas turbine inlet, a ceramic dispersed particle which is relatively stable even at a high temperature is introduced into an alloy, so that an ultra-high temperature is obtained. Oxide Dispersion Strengthed (ODS) alloy having excellent creep strength and extremely stable
Alloys) are in the limelight, and research and development are being actively pursued. This ODS alloy is described in, for example, U.S. Pat. Nos. 3,951,362, 3,732,092,
No. 723092, No. 3837930, and No. 3926
No. 568, etc.). Among them, MA956 alloy using an Fe-based alloy as an alloy matrix,
MA754 alloy and MA6000 alloy using an i-base alloy have been commercialized.

[0004] Since such an ODS alloy can maintain sufficient strength up to high temperatures and is also very excellent in corrosion resistance, its application to high-temperature parts is strongly expected. That is,
If the ODS alloy is applied to high-temperature parts, it is effective not only for improvement of high-temperature strength but also for measures against high-temperature corrosion and high-temperature oxidation. For example, a coating treatment of MCrAlY alloy or Al, which is currently adopted as the latter measure. This is because there is an advantage that the cost can be greatly reduced.

[0005]

However, the above-mentioned conventional ODS alloys generally have excellent properties such as high-temperature strength and high-temperature corrosion resistance.
In the case of the e-base alloy, the high-temperature strength as a high-temperature component material is insufficient, while in the case of the Ni-base alloy, there is a problem that the strength is sufficient but the workability is not always good. At present it is difficult to apply to high temperature parts.

The present invention solves the above-mentioned conventional problems, and makes the most of high-temperature strength and high-temperature corrosion-resistant properties, while having a more sufficient high-temperature strength as a high-temperature component material that can be actually applied. It is an object of the present invention to provide an oxide dispersion-strengthened alloy which has excellent workability and is more excellent in workability, and a method for producing the same.

[0007]

In order to achieve the above object, an oxide dispersion strengthened alloy according to the present invention comprises Cr, C
It is composed of a matrix of a Ni-based alloy containing o, Mo, W, Fe, Mn, Si, and C, and particles of Y ₂ O ₃ dispersed in the matrix. 0.0% or more 2
5.0% or less, the content of Co is more than 0% to 3.0% or less, and the total content of Mo and W is 7.
0% or more and 12.0% or less, and the content of Fe is 1
5.0% or more and 22.0% or less, the Mn content is more than 0% to 1.0% or less, and the Si content is 0% or less.
% To 1.0% or less, the C content to more than 0% to 0.5% or less, and the Y ₂ O ₃ content to 0.1% or less.
It is characterized by having a chemical composition of not less than 01% and not more than 10.0%, with the balance being Ni and unavoidable impurities. Particularly preferably, the content of Mo is 8.0% or more.
0% or less, and the content of W is 0.2% or more and 1.0% or less.
The following is assumed.

In another preferred embodiment, the oxide dispersion strengthened alloy according to the present invention is composed of Cr, Co, W, Fe, M
a matrix of a Ni-based alloy containing n, Si, and C, and particles of Y ₂ O ₃ dispersed in the matrix;
Is not less than 18.0% and not more than 25.0%,
The content of o is set to more than 0% to 3.0% or less, the content of W is set to 7.0% or more and 12.0% or less, and the content of Fe is set to 15.0% or more and 22.0%. Below, and the above Mn
Content of more than 0% to 1.0% or less, the content of Si is more than 0% to 1.0% or less, and the content of C is more than 0% and 0.5% or less. The content of Y ₂ O ₃ is set to 0.01% or more and 10.0% or less, and the balance is Ni
And have a chemical composition as unavoidable impurities. Particularly preferably, the content of W is set to 8.0% or more and 10.0% or less.

In the alloy according to the present invention, in order to further improve the high-temperature strength, Y ₂ O ₃ particles are preferably present in the matrix of the Ni-based alloy in a particle size distribution of 0.01 μm or more and 5 μm or more. It shall be dispersed in a state. Also, N
It is desirable that the oxygen content in the parent phase of the i-based alloy be 600 ppm or less.

According to the method of manufacturing an oxide dispersion strengthened alloy according to the present invention, Ni equivalent to any of the above alloys is used.
It is characterized in that Y ₂ O ₃ is dispersed as particles in the matrix of the Ni-based alloy by mechanically alloying each powder of the base alloy and Y ₂ O ₃ using a high energy mill. Here, the powder of the Ni-based alloy is preferably
A powder having a particle size distribution of 150 μm or less is used.

A high-temperature component for a gas turbine according to the present invention is characterized by being manufactured from the above-mentioned alloy. The gas turbine high-temperature component includes, for example, a gas turbine combustor liner.

The reasons for limiting the composition ranges of the respective constituent elements of the oxide dispersion strengthened alloy according to the present invention will be described below. Here, unless otherwise specified, the percentage (%) indicating the content of each element indicates wt%.

[0013] Cr is an indispensable element for improving oxidation resistance and corrosion resistance, and its content is 18.0.
%, The desired high-temperature corrosion resistance cannot be secured, and if it exceeds 25.0%, the ductility and toughness deteriorate. Therefore, the range of the Cr content is set to 18.0% or more and 2
It is defined as 5.0% or less, preferably 20.5% or more and 23.0% or less.

Co contributes to solid solution strengthening and has the property of improving high-temperature corrosion resistance. However, if its content exceeds 3.0%, high-temperature strengthening is reduced. Therefore, the range of the Co content is specified to be more than 0% and 3.0% or less, preferably 0.5% or more and 2.5% or less.

[0015] W and Mo are very effective elements as solid solution strengthening elements. However, since excessive addition significantly reduces toughness and heat embrittlement properties, the range of the total content of W + Mo is 7.0%. It is specified that the range of Mo content is not less than 8.0% and not more than 10.0%, and the range of W content is not less than 0.2% and not more than 1.0%. Also, Mo
In another embodiment that does not contain, the range of W content is 7.0.
% To 12.0%, preferably 8.0% to 10.
It was defined as 0% or less.

[0016] Fe plays an effective role as a solid solution strengthening element and has the property of improving malleability. However, if its content exceeds 22.0%, oxidation resistance is remarkably deteriorated. I will. Therefore, the range of the Fe content is set to 15.0% to 22.0%, preferably 17.0% to 20.0%.
It is specified as follows.

Mn is an important element as a desulfurizing and deoxidizing agent, and plays a role in stabilizing the structure. However, excessive addition degrades toughness. Therefore, the range of the Mn content is determined to be more than 0% and 1.0% or less.

Although Si is added as a deoxidizing agent, excessive addition causes significant embrittlement during high-temperature heating.
The range of the content was determined to be more than 0% and 1.0% or less.

C is a grain boundary strengthening element and plays a role in stabilizing the structure. However, if the content of C exceeds 0.5%, the toughness and workability are significantly deteriorated. The range is defined as 0.5% or less, preferably 0.05% or more and 0.2% or less.

Y ₂ O ₃ plays a role of improving creep strength by uniformly dispersing it by mechanical alloying. However, if its content exceeds 10.0%, ductility and workability are remarkably deteriorated. I will. Therefore, the range of the Y ₂ O ₃ content is defined as 0.01% or more and 10.0% or less, preferably 0.2% or more and 5.0% or less.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of an oxide dispersion strengthened alloy and a method for producing the same according to the present invention will be described.

(First Embodiment) Examples 1 to 16 Samples of Examples 1 to 16 having the chemical compositions shown in Table 1 were prepared as the alloys of the present invention. In preparing a sample, a raw material powder of a Ni-based alloy and a powder of Y ₂ O ₃ , which are adjusted in advance according to a target composition, are prepared.
The alloying treatment was mechanically performed using a high energy ball mill (attritor) for 8 hours. Therefore, the recovered powder is vacuum-sealed in a stainless steel capsule and kept at 1050 ° C. for 2 hours using a HIP (Hot Isostatic Pr
essing: hot isostatic pressing) and solidified. Thereafter, a flat bar was prepared by performing a hot rolling treatment at 1050 ° C., and a test piece was cut out from the flat bar.

[0023]

[Table 1]

Examples 1 to 4 obtained by such a manufacturing method
High-temperature tensile test (test temperature: 1000 ° C.) on each test piece to evaluate the high-temperature strength and hot workability of No. 16
To 0.2% proof stress (YS), maximum tensile stress (UT
S), elongation, and drawing were measured. Here, the measured values of elongation and drawing at high temperature indicate that the lower the value, the more likely it is to cause a processing resistance at high temperature and poor workability. Also, to evaluate oxidation resistance. The same test piece was subjected to an atmospheric high-temperature oxidation test (950 ° C., 1000 hours) to measure the mass increase.

For comparison, conventional alloys (MA754 and MA956) having the chemical compositions shown in Table 2 were produced under the same manufacturing conditions as described above, and the same tests were performed.

[0026]

[Table 2]

Tables 3 and 4 and FIGS.
Each is shown in FIG.

[0028]

[Table 3]

[0029]

[Table 4]

As shown in Tables 3 and 4 and FIGS. 1 to 3, according to the measurement results of the high-temperature tensile test, the alloy of the present invention has a thickness of 0.2%.
% Yield strength is 154 to 191 MPa, and maximum tensile stress is 174.
~ 219MPa, elongation 33 ~ 41%, aperture 41 ~ 5
The measured value was 3%, which was clearly higher than that of the conventional alloy, and was confirmed to be excellent in high-temperature strength and hot workability. This characteristic is especially true when the Mo content is 8.0-1.
In the case of Examples 1 and 2 in which the W content was set to 0.0% and the W content was set to 0.2 to 1.0%, the W content was set to 8.
It was remarkable in the case of Examples 3 and 4 set at 0 to 10.0%.

According to the measurement results of the high-temperature oxidation test in the air, the alloy of the present invention has a mass increase of 1.3 to 2.6 mg.
/ Cm ² , and the measured value was lower than that of the conventional alloy, and it was confirmed that the alloy exhibited excellent performance with respect to oxidation resistance. This characteristic was particularly remarkable in Examples 1 to 4 as described above.

Next, a comparative alloy will be described. Here, the upper limit value and the lower limit value of each element mean the component composition of each element of the present invention.

Comparative Examples 1 and 2 In Comparative Example 1, as shown in Table 1, the Cr content was set to the lower limit of 1
It is lower than 8.0%, and in Comparative Example 2, the content was set to exceed the upper limit of 25.0%, and the other conditions were the same as above. As a result, as shown in Table 3 and FIGS. 1 to 3, Comparative Example 1 having a low Cr content tends to have a particularly low oxidation resistance, and Comparative Example 2 having a high Cr content has a particularly low high-temperature strength. It was confirmed that there was a tendency to.

Comparative Example 3 In Comparative Example 3, as shown in Table 1, the Co content was set to exceed the upper limit of 3.0%, and the other conditions were the same as above. As a result, as shown in Table 3 and FIGS. 1 to 3, it was confirmed that in Comparative Example 3 having a high Co content, the high-temperature strength and the oxidation resistance particularly tended to decrease.

Comparative Examples 4 to 7 In Comparative Examples 4 and 5, the total content of W and Mo was lower than the lower limit of 7.0% as shown in Table 1, and in Comparative Examples 6 and 7, the same content was used. Was set to exceed the upper limit of 12.0%, and the other conditions were the same as those described above.
In addition, as shown in FIGS. 1 to 3, in each of Comparative Examples 4 and 5 in which the total content of W and Mo is low and Comparative Examples 6 and 7 in which the total content is high, particularly high-temperature strength and acid resistance It was confirmed that the chemical property tended to decrease.

Comparative Examples 8 and 9 In Comparative Example 8, as shown in Table 1, the Fe content was reduced to the lower limit of 1
It is lower than 5.0%, and in Comparative Example 9, the content was set to exceed the upper limit of 22.0%, and the other conditions were the same as those of the above-described invention alloy. As a result, Table 3 and FIGS.
As shown in FIG. 3, Comparative Example 8 having a low Fe content tends to have a particularly low strength at high temperatures and workability, and Comparative Example 9 having a low Fe content has a tendency to have a particularly degraded oxidation resistance. Was confirmed.

Comparative Example 10 In Comparative Example 10, as shown in Table 1, the Mn content was set to exceed the upper limit of 1.0%, and the other conditions were the same as those of the above-mentioned invention alloy. As a result, as shown in Table 3 and FIGS. 1 to 3, it was confirmed that in Comparative Example 10 having a high Mn content, particularly the high-temperature strength and the oxidation resistance were significantly reduced.

Comparative Example 11 In Comparative Example 11, as shown in Table 1, the Si content was set to exceed the upper limit of 1.0%, and the other conditions were the same as those of the above-mentioned invention alloy. As a result, as shown in Table 3 and FIGS. 1 to 3, in Comparative Example 11 having a high Si content, it was confirmed that the high-temperature strength was particularly reduced.

Comparative Example 12 In Comparative Example 12, as shown in Table 1, the C content was set to exceed the upper limit of 0.5%, and the other conditions were the same as those of the above-mentioned invention alloy. As a result, as shown in Table 3 and FIGS. 1 to 3, in Comparative Example 12 having a high C content, it was confirmed that the high-temperature strength was particularly significantly reduced.

Comparative Examples 13 and 14 In Comparative Example 13, as shown in Table 1, the Y ₂ O ₃ content was lower than the lower limit of 0.01%, and in Comparative Example 14, the Y ₂ O ₃ content was lower than the upper limit of 10.0%. %, And the other conditions were the same as those of the above-mentioned invention alloy. As a result, as shown in Table 3 and FIGS. 1 to 3, in Comparative Example 13 in which the Y ₂ O ₃ content was low, particularly, the high-temperature strength and the oxidation resistance were significantly reduced, and the Y ₂ O ₃ content was low. In Comparative Example 14, which was high, it was confirmed that workability was particularly reduced.

(Second Embodiment) Examples 17 to 20 In Examples 17 to 20, the same chemical composition as in Example 1 (see Table 1) was used, and the particle size distribution of the Y ₂ O ₃ particles was changed. Each test piece was prepared, and the high-temperature strength was evaluated by the same high-temperature tensile test as described above. As a result, as shown in Table 5, Y ₂ O
_In Example 17 in which the particle size distribution of the _three particles was 0.01 to 5.0 μm, 0.2% proof stress and 0.2% proof stress were obtained, as compared with Examples 18 to 20 in which the range of the particle size distribution was widened or shifted to a higher side. It was confirmed that the maximum tensile stress tended to be higher and the high temperature strength was more excellent.

[0042]

[Table 5]

(Third Embodiment) Examples 21 to 24 In Examples 21 to 24, the chemical composition was the same as that of Example 1 (see Table 1), and the oxygen content in the parent phase of the Ni-based alloy was varied. Each test piece was prepared under the following conditions, and the high-temperature strength was evaluated by the same high-temperature tensile test as described above. As a result, as shown in Table 6, in Example 21 in which the oxygen content was set as low as 500 ppm, the 0.2% proof stress and the maximum tensile stress were measured as compared with Examples 22 to 24 in which the oxygen content was high. The values tended to be higher, and it was confirmed that the high-temperature strength was further excellent.

[0044]

[Table 6]

[0045]

As described above, according to the present invention, the range of the component composition of each element is appropriately set for the above-mentioned reasons, and therefore, the conventional advantages relating to high-temperature strength stability and high-temperature corrosion resistance are utilized to the maximum. In addition, it is possible to provide an oxide dispersion-strengthened alloy having sufficiently high temperature strength as a high-temperature component material that can be actually applied and also having more excellent workability and a method for producing the same.

[Brief description of the drawings]

FIG. 1 is a graph illustrating a result of measuring a 0.2% proof stress by a high-temperature tensile test.

FIG. 2 is a graph illustrating a result of measuring a maximum tensile stress by a high-temperature tensile test.

FIG. 3 is a graph illustrating a measurement result of a mass increase by a high-temperature oxidation test.

Claims (9)

[Claims] 1. Cr, Co, Mo, W, Fe, Mn, S
It is composed of a matrix of a Ni-based alloy containing i and C and particles of Y ₂ O ₃ dispersed in the matrix, and the content of Cr is set to 18.0% or more and 25.0% or less. , The content of Co is set to more than 0% to 3.0% or less, and the total content of Mo and W is set to 7.0% or more.
0% or less, and the content of Fe is 15.0% or more 2
2.0% or less, the Mn content is more than 0% to 1.0% or less, the Si content is more than 0% to 1.0% or less, and the C content is 0% or less. %.
An oxide dispersion strengthened alloy having a chemical composition of not more than 5%, the content of Y ₂ O _{3 being not} less than 0.01% and not more than 10.0%, and the balance being Ni and unavoidable impurities. . 2. The content of Mo is 8.0% or more.
0% or less, and the content of W is 0.2% or more and 1.0% or less.
The oxide dispersion strengthened alloy according to claim 1, wherein: 3. A Cr-based alloy comprising a matrix of a Ni-based alloy containing Cr, Co, W, Fe, Mn, Si, and C, and particles of Y ₂ O ₃ dispersed in the matrix. Content of 18.0% or more and 25.0% or less, the content of Co is more than 0% and 3.0% or less, and the content of W is 7.0% or more and 12.0% or less. The content of Fe is 15.0% or more and 22.0% or less, the content of Mn is more than 0% and 1.0% or less, and the content of Si is more than 0% and 1% or more. 0.0% or less, and the content of C is more than 0% and 0.5% or less,
An oxide dispersion strengthened alloy having a chemical composition in which the content of Y ₂ O ₃ is 0.01% or more and 10.0% or less and the balance is Ni and unavoidable impurities. 4. The content of W is not less than 8.0% and not more than 10.0%.
%. The oxide dispersion-strengthened alloy according to claim 3, wherein the content is not more than%. 5. The method according to claim 1, wherein said Y ₂ O ₃
The oxide dispersion-strengthened alloy according to any one of claims 1 to 4, wherein the particles of (1) are dispersed in a state where the particle size distribution is 0.01 µm to 5 µm. 6. The oxide dispersion strengthened alloy according to claim 1, wherein the content of oxygen in the parent phase of the Ni-based alloy is 600 ppm or less. 7. Ni is obtained by mechanically alloying each powder of the Ni-based alloy and Y ₂ O _{3 according} to claim 1 using a high energy mill.
A method for producing an oxide dispersion strengthened alloy, comprising dispersing Y ₂ O ₃ as particles in a base phase of a base alloy. 8. The method according to claim 7, wherein a powder having a particle size distribution of 150 μm or less is used as the Ni-based alloy powder. 9. A high-temperature component for a gas turbine, which is made from the oxide dispersion strengthened alloy according to claim 1. Description: