JP2002235134A - Heat resistant alloy having excellent strength and toughness and heat resistant alloy parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a heat resistant alloy which has excellent strength and toughness, and can exhibit excellent characteristics over a long period even in a severe vapor environment where temperature and pressure are increased, and heat resistant alloy parts. SOLUTION: The heat resistant alloy having excellent strength and toughness has a composition containing, by weight, 50-55% Ni, 17 to 21% Cr, Nb or Nb and Ta by 4.75 to 5.5% in total, 2.8 to 3.3% Mo, 0.65 to 1.15% Ti, 0.2 to 0.8% Al, <=1.0% Co, <=0.08% C, <=0.35% Mn, <=0.35% Si, <=0.015% P, <=0.006% B and <=0.3% Cu, and the balance Fe with inevitable impurities. Its 0.2% cold proof stress at normal temperature after solution heat treatment and subsequent aging heat treatment is >=1,034 MPa, and Charpy impact value is >=50 J/cm2. The heat resistant alloy parts use this alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant alloy and a heat-resistant alloy part used for a long time at a high temperature. More specifically, the present invention relates to a heat-resistant alloy suitable for fastening parts and a fastening part made of this material.

[0002]

2. Description of the Related Art Conventionally, ferrite heat-resistant steels having the same physical properties as parts to be fastened and excellent in high-temperature properties have been used for fastening parts such as bolts in a high temperature portion of a steam turbine. However, in recent years, the efficiency of thermal power plants has been actively promoted against the background of environmental protection, and steam turbines using high-temperature steam at about 600 ° C. have been operated. In such a turbine, a heat-resistant ferritic steel cannot satisfy the required characteristics as a fastening part, and a heat-resistant alloy for forging having more excellent high-temperature characteristics tends to be used.

[0003]

However, although these alloys have excellent high-temperature properties, they are significantly embrittled by heating at about 600 ° C., making it difficult to operate them reliably for a long period of time, for example, tens of thousands of hours. . In addition, parts made of a material with low toughness have a low resistance to the impact force inevitably generated when they are removed at regular intervals, cracking,
Mechanical damage such as destruction is likely to occur.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and is intended to provide a heat-resistant alloy having high strength and high toughness and capable of stable operation by suppressing embrittlement at high temperatures for a long period of time. The purpose is to provide the alloy component.

[0005]

Means for Solving the Problems The present inventors have studied to develop a heat treatment method capable of imparting excellent ductility and toughness to the alloy and suppressing embrittlement at a high temperature for a long time. As a result, the present invention has been accomplished.

That is, the first invention of the present invention relates to
Ni: 50 to 55, Cr: 17 to 21, Nb or N
sum of b and Ta: 4.75 to 5.5, Mo: 2.8 to
3.3, Ti: 0.65 to 1.15, Al: 0.2 to
0.8, Co: 1.0 or less, C: 0.08 or less, Mn:
0.35 or less, Si: 0.35 or less, P: 0.015 or less, B: 0.006 or less, Cu: 0.3 or less,
The balance consists of Fe and unavoidable impurities, and has a normal temperature 0.2% proof stress of 1, after solution heat treatment and subsequent aging heat treatment.
034MPa or more and Charpy impact value is 50J / c
characterized in that m ² or more, an excellent heat-resistant alloy strength and toughness.

[0007] Further, the second invention is characterized in that 1,010 to 1,0
A heat-resistant alloy according to the first invention, which is characterized by being subjected to a solution heat treatment in a temperature range of 30 ° C. and having excellent strength and toughness.

In a third aspect of the present invention, an aging heat treatment is performed at 760 ± 8 ° C. after the solution heat treatment of the second aspect, and the temperature is reduced from the temperature to 704 ± 8 ° C. at a cooling rate of 50 ° C./h. Subsequently, the heat-resistant alloy according to the first aspect of the invention is characterized by being manufactured by performing an aging heat treatment at 704 ± 8 ° C. and air-cooling from the temperature.

A fourth invention is the heat-resistant alloy according to the third invention, which is characterized in that the material has a surface grain size of 6 or more in ASTM grain size number, and has excellent strength and toughness.

A fifth invention is the heat-resistant alloy having excellent strength and toughness according to the third invention, wherein the crystal grain size at the center of the material is 4 or more in ASTM grain size number.

[0011] The sixth invention is characterized in that the ratio of the Charpy impact value after 30,000 hours to that after the aging heat treatment is 0.8 to 0.8%.
A heat-resistant alloy having excellent strength and toughness according to the first to fifth aspects of the present invention, which is maintained as described above.

In a seventh aspect, the shrinkage ratio before and after the solution heat treatment of the second or third aspect is 0.08%.
The heat-resistant alloy according to the first to sixth aspects of the invention is excellent in strength and toughness.

According to an eighth aspect of the present invention, there is provided a heat-resistant alloy part comprising the heat-resistant alloy according to any one of the first to seventh aspects.
A heat-resistant alloy part excellent in strength and toughness, characterized by being exposed to a temperature of 6 ° C. or more and 649 ° C. or less.

According to a ninth aspect of the present invention, the shrinkage rate during use is 0.01% to 566 ° C.
An eighth aspect of the present invention is a heat-resistant alloy part excellent in strength and toughness, characterized in that:

A tenth invention is characterized in that the ninth invention is manufactured by performing shot peening after aging heat treatment to reduce residual stress of the surface layer to compressive stress.
A heat-resistant alloy part having excellent strength and toughness according to the ninth invention.

According to the present invention, there can be obtained the alloy having excellent toughness and less embrittlement during long-term operation at a high temperature and a fastening part made of the alloy.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the chemical composition of the alloy according to the present invention will be described. The preferred chemical composition of the alloy according to the invention comprises the elements and ranges given in Table 1. In addition, the remainder may include trace elements that are inevitably mixed. The alloy composed of these is AMS566
2. Ni, which is the same kind of material as specified in ASTM B670, JIS G4901, etc., and is strengthened mainly by precipitating a fine γ ″ phase (Ni ₃ Nb).
It is a base alloy. The alloy is prepared by a melting method known to those skilled in the art,
Using casting method, remelting method and forging method or rolling method,
Can be manufactured into round bars.

In the present invention, the reasons for limiting each component to the above range are as follows.

(A) Ni Ni is a main constituent element of the parent phase of the present alloy.
As a constituent element of the γ ″ phase and the γ ′ phase, it also contributes to precipitation strengthening.
Increases, the stability of the matrix phase composition decreases,
The content was 50 to 55%.

(B) Cr Cr mainly contributes to corrosion resistance and oxidation resistance. If it is less than 17%, the effect is not sufficient, and if it exceeds 21%, the precipitation amount of the αCr phase increases with high temperature and long time heating, and the toughness, corrosion resistance, and oxidation resistance decrease.
２１21%.

(C) Nb Nb contributes to solid solution strengthening and is a constituent element of the fine γ ″ phase (Ni ₃ Nb), which is the main strengthening phase of the present alloy, and contributes to precipitation strengthening. If it is less than 75%, the amount of precipitation cannot be sufficiently ensured, and if it exceeds 5.5%, the amount of undissolved coarse NbC increases, so that the content is 4.7.
It is set as 5 to 5.5%. The same applies to the case where a part of Nb is replaced with Ta, the total amount of Nb and Ta is limited to 4.75 to 5.5%, and the configuration of the γ ″ phase is (Ni ₃ (Nb, Ta)). The effect of can be expected.

(D) Mo Mo contributes to solid solution strengthening. If it is less than 2.8%, the strengthening amount is low, and if it exceeds 3.3%, the amount of precipitation of M ₆ C-type carbide due to high-temperature and long-time heating increases and embrittlement becomes severe. ３3.3%.

(E) Ti In the present alloy system, Ti forms a fine γ 'phase (Ni ₃ (Al, Ti)) together with Al and slightly contributes to precipitation strengthening. If it is less than 0.65%, the amount of precipitation cannot be sufficiently ensured. If it exceeds 1.15%, undissolved coarse TiC is formed, or the precipitation temperature range of the γ ″ phase in relation to the concentrations of Al and Nb. In order to reduce the content of 0.65-1.1
It is set as 5%.

(F) Al In the present alloy system, Al forms a fine γ 'phase (Ni ₃ (Al, Ti)) together with Ti, and slightly contributes to precipitation strengthening. If it is less than 0.2%, the amount of precipitation cannot be sufficiently ensured. If it exceeds 0.8%, the precipitation temperature range of the γ ″ phase is increased in relation to the concentrations of Ti and Nb. ０．８0.8%.

In the heat-resistant alloy according to the present invention, Si is added as a deoxidizing agent, Mn is added as a desulfurizing agent, and B is added for the purpose of stabilizing precipitates. ) And impurities incidentally added when adding Fe as a main component are desirably reduced as much as possible. Finally, the amount of elements remaining in the alloy is C:
0.08% or less, Co: 1.0% or less, Mn: 0.35
%, P: 0.015% or less, B: 0.006% or less, Cu: 0.3% or less.

Next, the alloy according to the present invention is used at room temperature.
The reason why the 2% proof stress has a Charpy impact value of 1,034 MPa or more and 50 J / cm ² or more will be described. The alloy has an ordinary temperature 0.2% proof stress of 1.0 in AMS5662 or the like.
Although it is specified as 34 MPa or more, it is difficult to secure an impact value of 50 J / cm ² or more with the alloy satisfying this value. The reason for this is that the δ phase remains even after the solution heat treatment in the above definition. On the other hand, in order to adjust the impact value to be high, as described in AMS5596 as an example, the solution heat treatment temperature is set to 1,040 to 1,065 ° C.
There is a method of performing aging heat treatment after the temperature is raised to a high temperature. However, in this case, a decrease in a predetermined proof stress, a decrease in fatigue strength, and a decrease in notch creep rupture characteristics may be caused. The reason for this is that the crystal grain coarsening became remarkable as the solution heat treatment temperature was increased. That is, it is difficult to increase both the 0.2% proof stress and the impact value to the above values by the existing heat treatment for the alloy. Therefore, as an alloy that achieves both high strength and high toughness and does not lower other properties than the existing alloy, the 0.2% proof stress and the impact value are limited.

Next, the reason why the grain sizes of the surface layer and the center in the present invention are set to ASTM grain size numbers of 6 or more and 4 or more, respectively, will be described. Forming to a state before solution heat treatment using a melting method, a forging method or a rolling method known to those skilled in the art results in a material having a different crystal grain size depending on the forming method and the degree of forming. In the present invention, preferably 1,010
One of the characteristics is that most of the δ phase is eliminated by solution heat treatment at 〜1,030 ° C., so that the growth of crystal grains is accelerated more than when the δ phase is continuously present on the grain boundaries. You. As described above, some mechanical properties of the coarse-grained material are lower than those of the fine-grained material. However, when the particle size is 6 or more, the proportion of the δ phase in the total grain boundary area becomes small, so that the impact value can be improved. It is effective in suppressing embrittlement. On the other hand, it is necessary that the creep rupture strength, rather than the toughness, is secured in the central portion. From this viewpoint, a coarse-grained material is desirable, but the solution heat treatment at 1,040 to 1,065 ° C. The obtained particle size is set to 4 or more because the fatigue strength and the fracture toughness decrease.

Next, in the present invention, 1,010 to 1,0
The reason for performing the solution heat treatment at 30 ° C. will be described. In order to make the alloy exhibit excellent high-temperature properties,
Solution heat treatment at ℃ is suitable, industrially 950 ~
It is often processed at 980 ° C. As a result, the plate-like δ phase generated before the solution heat treatment is formed at the crystal grain boundary (hereinafter, the grain boundary).
Presents the remaining tissue on top. Such a structure promotes intergranular fracture and crack propagation, and reduces impact properties and fracture toughness. Therefore, it was decided to heat them to 1,010 ° C. or higher at which the δ phase was dissolved to make them disappear. In order to impart excellent ductility to the present alloy, a solution heat treatment at 1,040 to 1,065 ° C. is considered to be suitable. However, in the present invention, 1,030
By setting the upper limit to ° C., it is possible to suppress the crystal grain size (hereinafter, the grain size) from being coarsened and to suppress the deterioration of the fatigue properties and the tensile properties.

Next, in the present invention, 1,010 to 1,0
The reason why the solution heat treatment is performed at 30 ° C., the aging heat treatment is performed at 760 ± 8 ° C., and the aging heat treatment is further performed at 704 ± 8 ° C. will be described. A temperature around 760 ° C. is a temperature range in which the γ ″ phase, which is the main strengthening phase of the alloy, is most actively precipitated, and most of the Nb dissolved in the parent phase after the solution heat treatment is mainly used as the γ ″ phase as crystal grains. It can be deposited at a high density inside (hereinafter, within the grains). In the present invention, since most of the δ phase is dissolved by the solution heat treatment, the solid solution N after the solution heat treatment is more than usual.
In the case where the amount of b is large and excellent strength is secured, it is necessary to secure a sufficient amount of precipitation of the γ ″ phase at this temperature. At a temperature higher than 760 ° C., the coarsening of the γ ″ phase is accelerated, and on the other hand, at a lower temperature side In this case, a sufficient amount of the γ ″ phase cannot be secured, and the strength is lowered in any case. Therefore, ± 8 ° C. is set as a temperature range that can be industrially applied centering on this temperature.
By performing the heat treatment in the vicinity, it becomes possible to grow a relatively large part of the γ ″ phase and to further reduce the amount of supersaturated Nb existing in a solid solution state. It is excellent in strength, and can suppress new precipitation of a γ ″ phase during use. However, when the final heat treatment temperature is higher than 704 ° C., γ ″
Since the phase coarsening is accelerated, the strength is reduced. On the other hand, the amount of solid-dissolved Nb cannot be reduced on the low-temperature side.
It was set. The reason why the cooling rate between the above two temperatures is set to 50 ° C./h is that the cooling rate is lower than this, the γ ″ phase becomes coarse during cooling, and this cooling rate is particularly industrial for large diameter materials. This is because the cooling speed is the fastest possible.

Next, the yield before and after the solution heat treatment and the aging heat treatment are described.
Reduction rate of 0.08% or more, and
The reason that the shrinkage ratio is 0.01% or less will be described. This
The alloy dissolves in the matrix Ni and the matrix by aging heat treatment.
Nb is combined with Ni ₃Nb as the basic structure
High strength is obtained by precipitating the γ ”phase in the grains,
The γ ”phase is a precipitate with a high atomic density,
It is known that the material shrinks. Conventional to this alloy
When the heat treatment is performed, the shrinkage is less than 0.08%.
Phase can be secured to obtain high strength.
Temperature to 1,010 to 1,030 ° C, δ phase
After the solution heat treatment of the present invention in which
Increases, so that the total amount of the precipitated γ ″ phase increases.
On the other hand, the γ ″ phase is heated at about 566 to 649 ° C.
Precipitation continues until Nb in the parent phase is depleted.
is there. Therefore, during use at about 566-649 ° C
Suppresses material shrinkage due to precipitation of γ ”phase for stable operation
Solution enabled and aging heat treatment completed to enable
At the moment, the matrix phase is almost depleted of Nb to achieve maximum contraction
And heating at about 566-649 ° C.
It is necessary to minimize the amount of the γ ″ phase precipitated during heating.

In the present invention, after the aging heat treatment, shot peening can be performed to reduce the residual stress in the surface layer to a compressive stress. The shot peening performed in the present invention is a method in which minute hard spheres collide with the alloy component at high speed. The reason for performing shot peening after the heat treatment will be described below. When a material is used in a device, an acting stress is generated, and in some cases, a thermal stress is generated. These often cause tensile stress especially on the surface of the material, and may accelerate mechanical damage such as cracking more than expected. However, tensile stress can be canceled out by generating compressive stress on the surface of the material by performing shot peening, and stable operation can be performed even under tensile stress.

Next, the reason why the alloy subjected to the heat treatment of the present invention is suitable for a heat-resistant alloy part, particularly a fastening part, such as a bolt or a nut, which is constantly used at a temperature of 566 ° C. or more and 649 ° C. or less will be described. If the alloy is subjected to a conventional heat treatment and used at a temperature exceeding 566 ° C. for a long time, the γ ″ phase becomes coarse and the structure change near the grain boundary becomes remarkably embrittled.
However, 1,010 to 1,030 ° C, 760 ± 8 ° C, 7
Heat treatment is performed sequentially at 04 ± 8 ° C to form a structure with no precipitates on the grain boundaries, so that the structure does not easily change during use, especially near the grain boundaries. However, embrittlement is suppressed. However, since the precipitation amount of the γ ″ phase in the grains increases, when the γ ″ phase is used for a long time at a temperature exceeding 649 ° C., the γ ″ phase is transformed into the αCr phase and the γ ″ phase is transformed into the δ phase. As it is accelerated, a steady upper limit for the operating temperature is set.

[0033]

Next, embodiments of the present invention will be described. [Example 1] In this example, the alloy of the present invention was used in an amount of 0.1%.
The fact that the 2% proof stress is not less than 1,034 MPa and the Charpy impact value is not less than 50 J / cm ² will be described.
The alloys shown in Table 2 in the chemical composition range of Table 1 were heat-treated under the five conditions shown in Table 3.

The heat-treated alloy was subjected to a Charpy impact test at 20 ° C. using a JIS No. 4 2 mm V-notch Charpy test piece, a diameter of 6 mm, and a distance between gauges of 30.
A tensile test was performed at room temperature using a mm-sized test piece with a collar (the conditions of the subsequent impact and tensile tests were the same). Table 4 shows the results. The example in which the heat treatment of H2 to H4 is performed is 0.1 mm.
Although the 2% proof stress and the impact value both showed high values, the comparative example subjected to the heat treatment of H1 had a high 0.2% proof stress but had a low impact value, and the comparative example subjected to the heat treatment of H5 exhibited a high value. Although it has an impact value, the 0.2% proof stress did not satisfy the standard value. From the above, it can be seen that the heat-resistant alloy according to the present invention satisfies the standard value of 0.2% proof stress and has an excellent impact value.

[Embodiment 2] In this embodiment, the effect when the crystal grain size of the surface layer is 6 or more by ASTM grain size number and the crystal grain size of the central part is 4 or more by ASTM grain size number will be described.

The alloys shown in Table 2 were heat-treated under the conditions shown in Table 3 under H3, H4 and H5 to adjust the alloys to have a wide range of crystal grain sizes. Since the final crystal grain size also depends on the crystal grain size of the material before the solution heat treatment, different grain size numbers can be obtained even if the same heat treatment is performed. 20 ° C impact value for the grain size number of these heat-treated materials,
Table 5 shows the fracture toughness and the creep rupture elongation at 650 ° C.-686 MPa.

If the particle size is 6 or more assuming the surface layer, H
The samples subjected to the heat treatments Nos. 3 and H4 exhibited an impact value of 100 J / cm ² or more, and also had a high fracture toughness value. In addition,
Samples having a particle size number of more than 4 could not be prepared in the sample subjected to the heat treatment of H5.

On the other hand, when the particle size was 4 or more assuming the central portion, the sample subjected to the heat treatment of H3 and H4 had a high creep rupture elongation, and the sample subjected to the heat treatment of H5 had a low creep rupture elongation. In addition, the creep rupture elongation was large in the sample of the grain size number 2 subjected to the heat treatment of H5, but in this sample, the macro deformation of the crystal grains was large and the deformation resistance was low.

From the above, when the crystal grain size according to the present invention is adjusted, the impact value and the fracture toughness value are excellent when the surface layer is assumed, and the creep rupture elongation is excellent when the center part is assumed. It can be seen that an alloy is obtained.

[Embodiment 3] In this embodiment, 1,010
The effect when the solution heat treatment is performed at １，1,030 ° C. will be described. The alloys shown in Table 2 were heat-treated under the conditions shown in Table 6. This alloy after the heat treatment was subjected to a Charpy impact test at 20 ° C and heating at 600 ° C for 30,000 hours.
Thereafter, a Charpy impact test at 20 ° C. was performed. Table 7 shows the results. The impact value (column A in the table) of the sample subjected to the heat treatment of H2, H4 and H7 is 50 J / cm ² or more, and the impact value after heating at 600 ° C. for 30,000 hours (B in the table).
Column) was 0.8 or more. In the heat-treated materials of H1 and H6, A in the table was 50 J / cm ² or less, and B / A in the table was low. The heat-treated material of H8 was high in both A in the table and B / A in the table, but had the same characteristics as the heat-treated material of H5 in Example 2.

From the above, 1,010 to 1,030
It can be seen that the alloy having a high impact value and low embrittlement after heating at a high temperature for a long time at a high temperature can be obtained by the solution heat treatment at ℃.

[Embodiment 4] In this embodiment, 1,010
After performing solution heat treatment at ~ 1,030 ° C, 760 ° C ±
The effect when the heat treatment is performed at 704 ° C. and further at 704 ° C. ± 8 will be described. The alloys shown in Table 2 were heat-treated under the conditions shown in Table 8. The heat-treated alloy was subjected to a tensile test at room temperature and a Charpy impact test at 20 ° C. Table 9 shows the results. The impact value of each heat-treated material was good. The 0.2% proof stress of the heat-treated material of H4 satisfies the standard value of the alloy, but H10 having a high aging temperature, H11 having the same low aging temperature, and H9 having a low cooling rate between the first and second aging temperatures are as follows. Both were below the standard value.

From the above, it can be seen that by setting the aging heat treatment and the cooling rate between the aging heat treatments according to the present invention, it is possible to impart sufficient proof stress to the alloy while securing a good impact value.

[Embodiment 5] In this embodiment, the effect of the shrinkage ratio before and after aging heat treatment and during long-term use within a predetermined numerical range will be described. The alloys shown in Table 2 were used in Table 3
Heat treatment was performed under the conditions indicated by H1 and H4. The heat-treated material was a disk having a diameter of 30 mm and a thickness of 10 mm, and the measurement of the shrinkage was calculated from the dimensional change in the thickness direction for each of five test specimens. Table 10 shows the results. The heat-treated material of H1 has a small shrinkage ratio after aging heat treatment of 0.08% or less,
After heating at 00 ° C. for 1,000 hours,
0.03% shrinkage occurs, corresponding to 100 MPa
The above increase in proof stress occurred. On the other hand, in the case of the H4 heat-treated material, although the shrinkage ratio after the aging heat treatment is larger than H1,
The shrinkage ratio after heating at 1,000 ° C. for 1,000 hours was one order of magnitude lower than that of H1, and the increase in proof stress was also small.

From the above, it can be seen that the alloy adjusted to the range of the shrinkage according to the present invention has a small change in strength during high-temperature use, and can be stably operated.

[Embodiment 6] In this embodiment, the effect of performing shot peening after heat treatment will be described.

The alloys shown in Table 2 were subjected to a heat treatment of H7, and thereafter, were subjected to shot peening. When shot peening is not performed for the residual stress at that time (H7 in the table)
The results are shown in Table 11 together with F). The residual stress on the surface of H7F was tensile stress (+), but the residual stress on the surface of shot-peened H7S was compressive stress (-). Table 11 also shows the residual stresses after exposing these to several conditions of tensile stress at 600 ° C. The residual stress of H7F was a tensile stress under any conditions, but H7S showed a compressive stress or ± 0.

From the above, it can be understood that the occurrence of excessive stress can be suppressed by performing shot peening after the heat treatment to reduce the residual stress of the material to the compressive stress, thereby enabling more stable equipment operation.

[0049]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[0050]

As described above, the heat-resistant alloy having excellent strength and toughness of the present invention can exhibit excellent properties for a long period of time even under a severe steam environment at high temperature and high pressure. Therefore, the use of the fastening part made of the heat-resistant alloy of the present invention brings about an industrially useful effect such as an improvement in operability and reliability of equipment.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01D 25/00 F01D 25/00 L // C22F 1/00 602 C22F 1/00 602 604 604 630 630A 630B 650 650A 651 651B 682 682 691 691B 692 692A 692B (72) Inventor Yoichi Tsuda 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Plant, Toshiba Corporation (72) Inventor Masayuki Yamada, Yokohama-shi, Kanagawa 2-4, Suehirocho, Tsurumi-ku F-term in Toshiba Keihin Works (reference) 3G002 EA04 EA06

Claims (10)

[Claims] (1) Ni: 50 to 55, Cr: 17 by weight%
~ 21, Nb or the sum of Nb and Ta: 4.75 ~
5.5, Mo: 2.8 to 3.3, Ti: 0.65 to 1.
15, Al: 0.2 to 0.8, Co: 1.0 or less, C:
0.08 or less, Mn: 0.35 or less, Si: 0.35 or less, P: 0.015 or less, B: 0.006 or less, Cu:
0.3% or less, with the balance being Fe and unavoidable impurities, a 0.2% proof stress at room temperature after solution heat treatment and subsequent aging heat treatment of not less than 1,034 MPa and a Charpy impact value of not less than 50 J / cm ^2. A heat-resistant alloy having excellent strength and toughness. 2. The heat-resistant alloy having excellent strength and toughness according to claim 1, wherein solution heat treatment is performed in a temperature range of 1,010 to 1,030 ° C. 3. After the solution heat treatment according to claim 2, 76
Perform aging heat treatment at a temperature of 0 ± 8 ° C.
At a cooling rate of 70 ° C./h to 704 ± 8 ° C.
The heat-resistant alloy having excellent strength and toughness according to claim 1, wherein the heat-resistant alloy is manufactured by performing an aging heat treatment at 04 ± 8 ° C and air-cooling from the temperature. 4. The heat-resistant alloy having excellent strength and toughness according to claim 3, wherein the crystal grain size of the material surface layer is 6 or more in ASTM grain size number. 5. The heat-resistant alloy having excellent strength and toughness according to claim 3, wherein the crystal grain size at the center of the material is 4 or more in ASTM grain size number. 6. A constant exposure to a temperature of 566.degree. C. to 649.degree. C., and the ratio of the Charpy impact value after 30,000 hours to the Charpy impact value after aging heat treatment is maintained at 0.8 or more. The heat-resistant alloy excellent in strength and toughness according to any one of claims 1 to 5, characterized in that: 7. The shrinkage ratio before and after the solution heat treatment according to claim 2 or 3, wherein the shrinkage ratio is 0.08% or more. A heat-resistant alloy with excellent strength and toughness described in 1. 8. A heat-resistant alloy part comprising the heat-resistant alloy according to any one of claims 1 to 7, wherein
A heat-resistant alloy part excellent in strength and toughness, characterized by being exposed to a temperature of 66 ° C or more and 649 ° C or less. 9. Excellent strength and toughness according to claim 8, characterized by being constantly exposed to a temperature of 566 ° C. or more and 649 ° C. or less and having a shrinkage rate of 0.01% or less during use. Heat resistant alloy parts. 10. An excellent strength and toughness according to claim 8 or 9, characterized in that it is manufactured by performing shot peening after aging heat treatment to reduce residual stress in the surface layer to compressive stress. Heat resistant alloy parts.