KR102374800B1 - Gas turbine disk material and heat treatment method therefor - Google Patents

Abstract

The gas turbine disk material according to the present invention contains: C: 0.05 to 0.15%, Ni: 0.25 to 1.50%, Cr: 9.0 to 12.0%, Mo: 0.50 to 0.90%, W: 1.0 to 2.0%, V: 0.10 to 0.30%; Nb: 0.01 to 0.10%, Co: 0.01 to 4.0%, B: 0.0005 to 0.010%, N: 0.01 to 0.05%, Mn: 0.40% or less, Si: 0.10% or less, Al: 0.020% or less, the balance is Fe and It consists of unavoidable impurities. In addition, as a heat treatment method, the hardening temperature of the forging material of the said component composition shall be 1050-1150 degreeC.

Description

Gas turbine disk material and heat treatment method therefor

The present invention relates to a gas turbine disk material and a heat treatment method therefor.

This application claims priority with respect to Patent Application No. 2017-181196 for which it applied to Japan on September 21, 2017, and uses the content here.

As a conventional gas turbine disk material, a so-called 12Cr-based heat-resistant steel containing about 8 to 12% Cr is widely used. This kind of gas turbine disk material contains Ni to secure toughness, and also contains Mo or V in addition to Cr to strengthen solid solution of the matrix structure and to strengthen dispersion by carbides or carbonitrides. Creep strength is improved.

As an example thereof, in Patent Document 1, C: 0.05 to 0.15%, Si: 0.10% or less, Mn: 0.40% or less, Cr: 9.0 to 12.0%, Ni: 1.0 to 3.5%, M _O : 0.50 to 0.90%, W: 1.0 to 2.0%, V: 0.10 to 0.30%, Nb: 0.01 to 0.10%, N: 0.01 to 0.05%, the balance consists of Fe and unavoidable impurities, and also Ni, Mo, A gas turbine disk material in which the content of W satisfies the relationship of -1.5%≤Mo+W/2-Ni≤0.5%, or one type of Co: 0.01 to 4.0%, B: 0.0001 to 0.010% in addition to each of the above components, or A gas turbine disk material containing two types is shown.

Japanese Laid-Open Patent Publication No. (Hei) 11-209851

By the way, in recent years, with the performance improvement of a gas turbine, the temperature of a gas turbine disk has become the operating temperature exceeding 500 degreeC, and the creep strength improvement is needed further. Although Ni-based alloy is excellent from a viewpoint of creep strength, since it becomes a large cost increase, it is desired to improve creep strength, maintaining the toughness of the 12Cr type|system|group heat-resistant steel of patent document 1.

The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a gas turbine disk material having further excellent creep properties and sufficient toughness, and a heat treatment method for manufacturing the same.

In order to solve the above problems, the present inventors conducted intensive experiments and studies, and as a result, the amount of Ni is set within an appropriate range lower than that of conventional 12C series heat-resistant steel, and the effective component range of N, Al, and B is made clear, so that the gas turbine As a disk material, it was discovered that creep characteristics can be improved remarkably compared to the prior art while securing toughness, and it led to the invention of a gas turbine disk material. In addition, it was found that creep characteristics and toughness can be reliably ensured by optimizing the quenching temperature of the forging as a heat treatment in the production of a gas turbine disk material, and heat treatment for manufacturing a gas turbine disk material came to the invention of the method.

Specifically, the gas turbine disk material of the basic aspect (1st aspect) of this invention,

in mass %,

C: 0.05-0.15%;

Ni: 0.25 to 1.50%,

Cr: 9.0 to 12.0%,

Mo: 0.50 to 0.90%,

W: 1.0 to 2.0%,

V: 0.10 to 0.30%;

Nb: 0.01-0.10%,

Co: 0.01 to 4.0%,

B: 0.0005 to 0.010%;

N: 0.01 to 0.05%,

Mn: 0.40% or less;

Si: 0.10% or less;

Al: 0.020% or less

It is characterized in that it contains Fe and the balance consists of unavoidable impurities.

Moreover, the gas turbine disk material of the 2nd aspect of this invention WHEREIN: In the gas turbine disk material of the said 1st aspect, ratio [N%]/[N content [N%] and Al content [Al%] Al%] is characterized in that 2.4 or more.

Moreover, the gas turbine disk material of a 3rd aspect of this invention WHEREIN: In the gas turbine disk material of the said 1st or 2nd aspect, the sum of 0.5 times of content [B%] of B and content of N [N%] It is characterized in that the B equivalent represented by ([B%] + 0.5 [N%]) is 0.0055 to 0.030%.

Moreover, the gas turbine disk material of a 4th aspect of this invention WHEREIN: In the gas turbine disk material of any one of said 1st thru|or 3rd aspect, the absorbed energy in a room temperature Charpy impact test is 40 J or more. characterized in that

Further, in the gas turbine disk material of the fifth aspect of the present invention, in the gas turbine disk material of any one of the first to fourth aspects, the creep rupture time at 596°C × 310 MPa is 750 hours or more, do.

In addition, in the heat treatment method of a gas turbine disk material of a sixth aspect of the present invention, the forging material having any one of the first to third aspects is heated and quenched, and then tempering heat treatment is performed. , characterized in that the quenching temperature is within the range of 1050 to 1150 °C.

ADVANTAGE OF THE INVENTION According to the gas turbine disk material of the 1st aspect of this invention, the balanced material characteristic which made high creep strength and high toughness compatible can be ensured.

In addition, according to the regulation of minor components of the second or third aspect of the present invention or the heat treatment method of the sixth aspect, it is possible to reliably and stably obtain a gas turbine disk material having high toughness while further improving creep strength. there is.

BRIEF DESCRIPTION OF THE DRAWINGS It is a graph which shows the relationship between Ni content of a gas turbine disk material, evaluation value of toughness (absorbed energy), and evaluation value of high temperature creep characteristic (creep rupture time).
2 is a graph showing the relationship between the ratio [N%]/[Al%] of the Ni content [N%] and the Al content [Al%] of the gas turbine disk material and the evaluation value (creep rupture time) of the high temperature creep characteristics It is a graph.
3 shows the ratio [N%]/[Al%] of the N content [N%] and the Al content [Al%], and the B content [B%] and the N content in the gas turbine disk material. It is a graph showing the preferable range of the B equivalent ([B%] + 0.5 [N%]) expressed as a sum of 0.5 times [N%].

First, the reason for limiting the component composition of the gas turbine disk material of one aspect|mode of this invention is demonstrated.

<Reason for limiting the composition of ingredients>

[C: 0.05 to 0.15%]

C is an element that secures hardenability and combines with Cr, Mo, Nb, V, Nb, etc. to form fine and high-hardness carbides or carbonitrides while at the same time greatly affecting high-temperature strength. However, if the content is less than 0.05%, sufficient amounts of carbides and carbonitrides cannot be formed, and a uniform martensitic structure cannot be obtained. That is, when the amount of C is less than 0.05%, a mixed structure of martensite and delta ferrite is formed, and the high-temperature strength and high-temperature fatigue strength are remarkably reduced. On the other hand, at a content exceeding 0.15%, not only the toughness decreases, but also the cohesive coarsening of carbides and carbonitrides during use at high temperatures becomes remarkable, resulting in a decrease in creep rupture strength. Therefore, the C content is set to 0.05 to 0.15%.

[Ni: 0.25 to 1.50%]

Ni is an element capable of improving hardenability and toughness at room temperature, and can satisfy desired toughness at 0.25% or more. On the other hand, when the amount of Ni exceeds 1.50%, the toughness is improved, but the creep rupture strength is remarkably lowered, and it becomes unsuitable as a gas turbine disk material used at a high temperature exceeding 500°C. Accordingly, the Ni content is set to 0.25 to 1.50%. As described above, the amount of Ni is an element that affects toughness and creep properties in the opposite direction, and therefore, as an appropriate Ni amount range that can make high temperature creep properties and toughness compatible, it is defined within the range of 0.25 to 1.50%. As described above, an appropriate Ni content of 0.25 to 1.50% was newly discovered by experiments by the present inventors and the like, and the experiment will be described again later.

Further, in consideration of the high temperature creep characteristics, the Ni content may be 0.25% to 0.99%, or 0.25% to 0.90%.

[Cr: 9.0 to 12.0%]

Cr improves oxidation resistance and creep rupture strength. However, when the Cr content is less than 9.0%, sufficient oxidation resistance and creep rupture strength cannot be obtained. On the other hand, when Cr is contained in excess of 12.0%, the creep rupture strength does not decrease much, but delta ferrite is precipitated and the toughness and high temperature fatigue properties are deteriorated. Therefore, the Cr content is set to 9.0 to 12.0%.

[Mo: 0.50 to 0.90%]

Mo improves high temperature strength and creep rupture strength by two actions: solid solution strengthening and precipitation strengthening. However, when the Mo content is less than 0.50%, the effect is small, and when the Mo content exceeds 0.90%, delta ferrite is formed, which may deteriorate toughness and creep rupture strength. Therefore, the Mo content is set to 0.50 to 0.90%.

[W: 1.0 to 2.0%]

W is an element that improves high-temperature strength and creep rupture strength. However, when the W content is less than 1.0%, the effect is not sufficiently obtained. Moreover, when W content exceeds 2.0 %, there exists a possibility that delta ferrite which harms a high temperature characteristic may precipitate. Therefore, the W content is set to 1.0 to 2.0%.

[V: 0.10 to 0.30%]

V is an element that forms carbide (V ₄ C ₃ ) and nitride (VN), and also forms complex carbonitride (Nb, V) (C, N) with Nb to increase high-temperature strength and creep rupture strength. However, if the V content is less than 0.10%, the effect is not sufficient, and if the V content exceeds 0.30%, the carbides and carbonitrides coagulate and coarsen during long-term use, resulting in a decrease in creep rupture strength. Therefore, the V content is set to 0.10 to 0.30%.

[Nb: 0.01 to 0.10%]

Nb is an element that forms a carbide (NbC) and also forms a complex carbonitride (Nb, V) (C, N) with V to increase high-temperature strength and creep rupture strength. However, when the content of Nb is less than 0.01%, the effect is small, and when the content exceeds 0.10%, carbides and carbonitrides are not sufficiently dissolved even at a high quenching temperature of 1100° C. Cohesion coarsens, and creep rupture strength falls. Therefore, the Nb content is set to 0.01 to 0.10%.

[Co: 0.01 to 4.0%]

Co is an element effective in improving the high-temperature strength and creep rupture strength by increasing the solid solution capacity of carbides and carbonitrides into the matrix, and Co itself also exhibits a solid solution strengthening action. However, when the Co content is less than 0.01%, the effect is small, and when the Co content exceeds 4.0%, the toughness and creep rupture strength are lowered. Therefore, the Co content is set to 0.01 to 4.0%.

[B: 0.0005 to 0.010%]

B is an element that increases high-temperature strength and creep rupture strength. However, when the content of B is less than 0.0005%, the effect is small, and when B content exceeds 0.010%, eutectic Fe ₂ B and BN are produced when heated to 900 to 1200 ° C during forging, It adversely affects hot workability and mechanical properties. Therefore, the B content is set to 0.0005 to 0.010%. In addition, as will be explained again later, the B content is adjusted so that the B equivalent (B+0.5N) expressed as the sum of the B content [B%] and the N content [N%] 0.5 times is 0.030% or less It is preferable to do

[N: 0.01 to 0.05%]

N is an element that contributes to the improvement of high-temperature strength and creep rupture strength through precipitation of carbonitrides of Nb or V by appropriate heat treatment, and is effective in preventing the formation of delta ferrite. However, when the N content is less than 0.01%, the effect is not sufficiently exhibited, and when the N content exceeds 0.05%, the toughness decreases. Therefore, the N content is set to 0.01 to 0.05%. In addition, when Al is contained in steel, N is fixed as AlN, and the amount of N (effective nitrogen amount) contributing for the production|generation of carbonitride of Nb or V decreases. Therefore, as will be explained later, the amount of N is adjusted according to the amount of Al in the steel so that the ratio [N%]/[Al%] of the N content [N%] and the Al content [Al%] in the steel is 2.4 or more. It is preferable to do

In addition, in order to suppress the generation of BN harmful to hot workability and mechanical properties, the B equivalent (B+0.5N) expressed as the sum of the B content [B%] and the N content [N%] 0.5 times is 0.030 % or less, it is preferable to adjust the N amount according to the B content.

[Mn: 0.40% or less]

Mn is an element that is often used as a deoxidizer when smelting steel, and is also contained as an impurity in steel in many cases. The effect as a deoxidizer is sufficiently achieved with a Mn content of 0.40% or less. Moreover, since Mn is an element which promotes embrittlement, it is preferable that there is little content. Therefore, the Mn content is regulated to 0.40% or less.

[Si: 0.10% or less]

Like Mn, Si is often used as a deoxidizer at the time of melting of steel, and is an element that is contained as an impurity in many cases. At Si content exceeding 0.10%, segregation in a large-sized steel ingot becomes severe, and toughness after long-time use falls. Therefore, the Si content is regulated to 0.10% or less.

[Al: 0.020% or less]

It originates in Al used as a deoxidizer at the time of solvent, and a trace amount of Al is contained as an impurity. Since Al reduces the effective nitrogen amount by fixing N as AlN, and reduces the carbonitride production amount such as Nb or V, thereby lowering the high temperature strength and creep rupture strength, the Al amount is preferably very small, regulated to 0.020% or less made it Further, since the amount of N is also related to the amount of carbonitride produced, it is preferable to set the [N%]/[Al%] ratio to 2.4 or more as will be described later.

The balance of each of the above elements is Fe and unavoidable impurities. Examples of these impurities include P, S, and the like, but since these elements make the material brittle and adversely affect impact properties, the content thereof is preferably extremely small. Preferably, it is made into 0.015% or less.

In addition, the appropriate range of the amount of Ni and the [N%]/[Al%] ratio described as the reason for limiting the components will be described next based on the experiments of the present inventors and the like.

<About the appropriate range of Ni amount>

In the 12Cr-type heat-resistant steel of the turbine disk material shown in patent document 1, Ni is contained in 1.0 to 3.5% of range. However, in such a turbine disk material, creep rupture strength is insufficient at a service temperature significantly exceeding 500 degreeC, and the improvement of creep strength is required further.

Therefore, as a result of repeated experiments and examinations by the inventors of the present invention in detail, setting the Ni content within the range of 0.25 to 1.50% lower than that of the turbine disk material of Patent Document 1 is a high temperature creep characteristic while securing the toughness required as a gas turbine disk material. It was found that it can be used even at a working temperature significantly exceeding 500°C by further improving the .

In addition, in consideration of the high temperature creep characteristics, the Ni content according to the present invention may be 0.25% to 0.99%, or 0.25% to 0.90%, which is lower than the Ni content of the turbine disk material in Patent Document 1.

That is, the present inventors investigated the toughness and high-temperature creep characteristics under high stress for a forging of 12Cr-based heat-resistant steel with various Ni amounts changed after heat treatment, and results as shown in FIG. 1 are obtained. Here, the components in the 12Cr-based heat-resistant steel provided for the experiment are the test materials J1 to J3 of Examples in Table 1 and the test materials C1, C4, AL15, and AL20 of Comparative Examples. The forging was heated to 1050° C. or 1090° C., held for 3.5 hours, quenched by oil cooling, and then tempered at 670° C. to use for material testing.

Table 2 shows the results of the room temperature tensile test and the room temperature Charpy impact test. In Table 3, the creep rupture time in the test condition of 596 degreeC x 310 MPa is shown. The result of having put together the test result in a table with the amount of Ni of a test material is shown in FIG.

In addition, from Table 2 and FIG. 1, although the 0.2% yield strength and tensile strength are all about the same, the absorbed energy changes greatly. Absorbed energy increases and toughness improves, so that the amount of Ni is large. When the amount of Ni is 0.25% or more, the absorbed energy of 40 J or more required as a gas turbine disk material can be obtained.

From Table 3 and FIG. 1, the creep rupture time becomes long, so that there is little Ni amount, and high temperature creep characteristic improves. In addition, the higher the quenching temperature, the longer the creep rupture time, and in the case of quenching at 1090°C, the creep rupture time of 750 hours or more required as a gas turbine disk material can be obtained even if the Ni content is at most 1.5%. On the other hand, in the case of quenching at 1050° C., if the minimum value of the Ni amount required for securing the aforementioned toughness is 0.25%, a creep rupture time of 750 hours or more required as a gas turbine disk material can be obtained.

From the above test results, the toughness (the absorbed energy by the room temperature Charpy impact test is 40 J or more) required as a gas turbine disk material and the creep strength (the creep rupture time in 596 degreeC x 310 MPa is 750 hours or more) are compatible. As such, after the quenching temperature was set to 1050° C. or higher, the Ni content was set to an appropriate range from 0.25 to 1.50%.

<About the [N%]/[Al%] ratio>

In order to improve the creep rupture strength on the high temperature and low stress side, it is effective to increase the amount of precipitation of fine precipitates mainly composed of carbonitrides of Nb and V. For this purpose, it is necessary to provide a sufficient amount of effective N, which contributes to carbonitride formation in steel, to be dissolved in a matrix at the time of quenching.

On the other hand, in the case of this kind of steel smelting, Al is used as a deoxidizer in many cases, Therefore, Al exists in steel in many cases. And Al combines with N to fix N as AlN. Therefore, if the amount of N is too small with respect to the amount of Al, the amount of N (effective nitrogen amount) effective for producing carbonitrides of Nb and V decreases, and a sufficient amount of carbonitride does not precipitate.

And when the present inventors investigated the influence of the ratio [N%]/[Al%] of the N content [N%] and the Al content [Al%] in the steel on the creep strength, as shown in Fig. 2, 1090 °C hardened material WHEREIN: [N%]/[Al%] was less than 2.4, and it was discovered that creep rupture time falls rapidly. Therefore, [N%]/[Al%] is preferably set to 2.4 or more in order to sufficiently secure an effective nitrogen amount that is not fixed as AlN, and to sufficiently precipitate Nb and V carbonitrides to ensure high creep rupture strength.

In order to set [N%]/[Al%] to 2.4 or more, a method of increasing the N amount or regulating the Al amount to a small amount is considered, but when the N amount exceeds 0.05% and becomes excessive, as described above Since there is a fear that BN, which is harmful to hot workability and mechanical properties, is generated, it is preferable to apply means for regulating the amount of Al.

<About B equivalent ([B%]+0.5[N%])>

When B and N are added in large amounts, eutectic Fe ₂ B and BN are generated when heated to 900 to 1200° C. during forging, which adversely affects hot workability and mechanical properties. Therefore, as shown in Japanese Patent No. 2948324, the B content so that the B equivalent (B+0.5N) expressed as the sum of the B content [B%] and the N content [N%] 0.5 times is 0.030% or less It is desirable to adjust the amount of N according to On the other hand, since B and N are elements effective for high-temperature strength improvement, it is necessary to contain 0.0005% or more of B and 0.01% or more of N, so the lower limit of the equivalent of B ([B%] + 0.5 [N%]) is It was set as 0.0055%.

In Fig. 3, preferable ranges of [N%]/[Al%] and B equivalent ([B%] + 0.5 [N%]) in the present invention are shown.

<Production method (heat treatment method)>

The manufacturing method of the gas turbine disk material including the heat processing method of the other aspect of this invention is demonstrated below.

The alloy of the above composition is melted according to a conventional method and cast to form an ingot. After the obtained ingot is subjected to a homogenization treatment as necessary, it is heated to, for example, 900 to 1200° C. and hot forged. The obtained forging material is subjected to a temper heat treatment of quenching-soaking. This temper heat treatment step is a heat treatment method as another aspect of the present invention.

The temper heat treatment is a process necessary for improving creep strength by precipitating carbides or carbonitrides while obtaining high strength desired for gas turbine disk materials by making the steel structure into a substantially uniform martensitic structure. That is, by heating the forging material to a high temperature, austenitization of the steel structure is achieved, and elements contributing to the formation of carbides and carbonitrides are once dissolved in the matrix, and then quenched (quickly cooled) to achieve martensite formation. This is a necessary step to make the element contributing to the formation of carbides and carbonitrides supersaturated and dissolved in steel, and to precipitate carbides and carbonitrides finely by soaking.

Here, the higher the quenching temperature (heating temperature for quenching) is, the greater the high capacity of C, N, Nb, and V contributing to carbonitride production can be increased, and as a result, the amount of precipitation of Nb or V carbonitrides precipitated by soaking. Creep strength can be improved by increasing the On the other hand, when the quenching temperature is too high, coarsening of crystal grains occurs, resulting in a decrease in toughness. Therefore, in order to improve the creep strength while not impairing the toughness, there is an appropriate temperature range for the quenching temperature.

The present inventors performed quenching at a quenching temperature of 1050 ° C. or 1090 ° C., and using a test material soaked at 670 ° C., the effect of quenching temperature on toughness and creep strength was investigated, Table 2, Table 3 and Figures The result shown in 1 was obtained.

The components in the 12Cr-based heat-resistant steel provided for the experiment are each of the test materials of Examples in Table 1 and each test material of Comparative Examples. The forging was heated to 1050 or 1090°C, held for 3.5 hours, quenched by oil cooling, and then soaked at 670°C, and used for material testing.

From Table 2, Table 3, and FIG. 1, the absorbed energies of the specimens of the quenching temperature of 1050 degreeC and 1090 degreeC are equal, and the influence of the quenching temperature on absorbed energy is not recognized. On the other hand, the creep rupture time is longer in the quenching at 1090°C than in the quenching at 1050°C, and the creep rupture strength is higher in the case where the quenching temperature is higher.

From the above results, the higher the quenching temperature, the longer the creep rupture time and the higher the high-temperature creep strength. Even in quenching at 1050° C., if the minimum value of Ni required to secure the aforementioned toughness is 0.25%, 750 hours or more required as a gas turbine disk material Since creep rupture time was obtained, it was set as 1050 degreeC as minimum temperature. When it exceeds 1150 ° C, it enters the temperature range where delta ferrite is precipitated, and also causes a significant coarsening of the grain size to reduce toughness, so the quenching temperature range was 1050 to 1150 ° C. Preferably, it is around 1090 degreeC.

Example

Examples of the present invention will be described below together with comparative examples. In addition, the following examples are examples for verifying the effect of the present invention, and it goes without saying that the conditions of the examples do not limit the scope of the present invention.

Steel ingots were prepared by an electroslag remelting process so that the chemical components shown in the test materials J1 to J3 of Examples and Comparative Examples C1, C4, AL15, AL20 of Table 1 were obtained. This was heated to 900 to 1200° C. and forged to produce a disk-shaped forging. The forging was heated to 1050°C or 1090°C, held for 3.5 hours, quenched by oil cooling, and then soaked at 670°C.

A tensile test piece is produced from each of the forgings after soaking, a room temperature tensile test is performed in accordance with the tensile test method of JIS Z 2241, and a Charpy V-notch impact test piece is produced, and an impact test is performed in accordance with the Charpy impact test method of JIS Z 2242 did The result is shown in Table 2.

Further, from the same specimen, a round bar-shaped smooth test piece for the creep rupture test was produced, and a creep rupture test was performed under the conditions of 596° C. × 310 MPa in accordance with the high-temperature creep test method of JIS Z 2272. The result is shown in Table 3.

Examples of test materials J1 to J3 are examples of the present invention within the component composition range prescribed in the present invention. The room temperature shock absorption energy satisfies 40 J required as a gas turbine disk material. Moreover, in the 1090 degreeC hardened|hardened material, the creep rupture time of 596 degreeC x 310 MPa x 750 hours or more required as a gas turbine disk material was satisfied.

On the other hand, it was found that Comparative Example C1 having a high Ni content had a remarkably short creep rupture time and was inferior in high temperature strength. This comparative example C1 is a comparative example corresponding to the material described in patent document 1, On the other hand, it is clear that the creep strength of this invention examples J1-J3 is improved significantly. Moreover, Comparative Example C2 with a low amount of Ni has a low room temperature absorbed energy of 20 J, and does not satisfy 40 J required as a gas turbine disk material.

Moreover, as shown in FIG. 2, in Comparative Examples AL15 and AL20, compared with Examples J1-J3, it turns out that creep strength falls rapidly in the low N/Al area|region. It turns out that in order to secure creep rupture strength stably, it is necessary to raise N/Al to 2.4 or more.

As mentioned above, although preferred embodiment and Example of this invention were described, this embodiment and Example are only examples within the scope of the gist of the present invention, and are constructed within the scope not departing from the gist of the present invention. addition, omission, substitution, and other changes are possible.

ADVANTAGE OF THE INVENTION According to the gas turbine disk material which concerns on this invention, the balanced material characteristic which made high creep strength and high toughness compatible can be ensured.

Further, according to the trace component regulation and heat treatment method according to the present invention, a gas turbine disk material having high toughness while further improving creep strength can be reliably and stably obtained.

Claims (9)

in mass %,
C: 0.05-0.15%;
Ni: 0.25 to 1.50%,
Cr: 9.0 to 12.0%,
Mo: 0.50 to 0.90%,
W: 1.0 to 2.0%,
V: 0.10 to 0.30%;
Nb: 0.01-0.10%,
Co: 0.01 to 4.0%,
B: 0.0005 to 0.010%;
N: 0.01 to 0.05%,
Al: More than 0% and less than 0.020%
contains, and the balance consists of Fe and unavoidable impurities,
The ratio [N%]/[Al%] of the content of N [N%] and the content of Al [Al%] is 2.4 or more,
B equivalent ([B%] + 0.5 [N%]) expressed as the sum of the content of B [B%] and 0.5 times the content of N [N%] is 0.0055 to 0.030%, characterized in that
Gas turbine disk material. According to claim 1,
% by mass, containing more than 0% and not more than 0.40% Mn
Gas turbine disk material. According to claim 1,
% by mass, containing more than 0% and not more than 0.10% of Si
Gas turbine disk material. According to claim 1,
Ni content is 0.79 to 1.50% by mass, characterized in that
Gas turbine disk material. 5. The method of claim 1 or 4,
The content of Cr is 10.17 to 12.0% by mass, characterized in that
Gas turbine disk material. According to claim 1,
The content of the unavoidable impurity is 0.015% or less in mass%, characterized in that
Gas turbine disk material. According to claim 1,
Absorbed energy in the room temperature Charpy impact test is 40 J or more, characterized in that
Gas turbine disk material. According to claim 1,
Creep rupture time at 596°C × 310 MPa is 750 hours or more
Gas turbine disk material. The forging material having the component composition according to claim 1 is heated and quenched, and thereafter, in performing a soaking heat treatment,
Characterized in that the quenching heating temperature is in the range of 1050 to 1150 ° C.
A heat treatment method for a gas turbine disk material.

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