WO2010146999A1

WO2010146999A1 - FERRITIC Cr-STEEL FOR HEAT-RESISTANT PRECISION COMPONENT AND METHOD FOR PRODUCING SAME, AND HEAT-RESISTANT PRECISION COMPONENT AND METHOD FOR PRODUCING SAME

Info

Publication number: WO2010146999A1
Application number: PCT/JP2010/059453
Authority: WO
Inventors: 一弘木村; 佳明戸田; 秀昭九島; 浩太澤田
Original assignee: 独立行政法人物質・材料研究機構
Priority date: 2009-06-17
Filing date: 2010-06-03
Publication date: 2010-12-23
Also published as: EP2444508A1; EP2444508A4; US20120132325A1; JP5713250B2; JP2011001574A

Abstract

Disclosed is a ferritic Cr-steel for a heat-resistant precision component, which contains Cr in an amount of 13-30% by mass (inclusive) and has a thermal expansion coefficient of 15 × 10^-6 or less in a temperature range from room temperature to 800˚C and a minimum creep rate of 1 × 10^-4/h or less at 700˚C at 100 MPa. The ferritic Cr-steel for a heat-resistant precision component is produced by being formed into a predetermined shape by hot working within a temperature range of 850-1200˚C, then being subjected to annealing within a temperature range of 1000-1250˚C, and then being cooled to 400˚C or less at a cooling rate of 100˚C/min or more. The production of this ferritic Cr-steel enables achievement of a heat-resistant precision component such as a rotor, disc or blade for a turbine, which can withstand use at high temperatures more than 600˚C.

Description

Ferritic Cr steel for heat-resistant precision parts and manufacturing method thereof, and heat-resistant precision parts and manufacturing method thereof

The present invention relates to a ferritic Cr steel which is a material for precision parts having heat resistance.

For example, heat-resistant precision parts (hereinafter referred to as heat-resistant precision parts), such as rotors and disks such as steam turbines and gas turbines used at high temperatures, and blades (hereinafter referred to as heat-resistant precision parts) have a large thermal expansion coefficient. Conventionally, ferritic Cr steel (so-called ferritic high Cr steel) has been generally used as the material because there is an error in the arrangement relationship with other parts.

However, as the turbine is required to be used at a high temperature exceeding 650 ° C., a Ni-base superalloy described in Patent Document 1 has been proposed as a material for heat-resistant precision parts.

The reason is that ferritic Cr steel, which has a small dimensional change due to thermal expansion, has low high-temperature strength, and the shape of precision parts changes due to creep deformation.

However, due to the physical properties of Ni-base superalloys, it is not only possible to keep the thermal expansion coefficient below the value of ferritic Cr steel, but rather, further improvement in heat resistance increases the thermal expansion coefficient. Tend to.

As described above, there is a dilemma that a ferritic Cr steel having a small thermal expansion coefficient has a large creep deformation amount, and a Ni-base superalloy having a small creep deformation amount and high high-temperature strength has a large thermal expansion coefficient.

Therefore, it has been extremely difficult to realize a heat-resistant precision component that can withstand use at a high temperature exceeding 650 ° C. and that has a small shape and dimensional change.
JP 2007-332412 A

The present invention has been made in view of such circumstances, and has improved heat resistance while exhibiting low thermal expansion, and a ferritic Cr steel for heat-resistant precision parts, a manufacturing method thereof, and heat-resistant precision parts. And providing a manufacturing method thereof.

In order to solve the above problems, the ferritic Cr steel for heat-resistant precision parts of the present invention is a ferritic Cr steel for precision parts having heat resistance, and its chemical composition is in mass%.
Cr: 13-30%
Ni: 1 × 10 ⁻¹ to 2.5%,
C: 1 × 10 ⁻³ to 1 × 10 ⁻¹ %, and N: 1 × 10 ⁻³ to 1 × 10 ⁻¹ %
Is contained, the inclusion of an additive component and an unavoidable impurity is permitted, the balance is Fe, and a ferrite phase is formed.

In this ferritic Cr steel for heat-resistant precision parts, when either or both of the addition amount of C is 1 × 10 ⁻² mass% or more and the addition amount of Ni is 1 × 10 ⁻² mass% or more, Ni The addition amount of
Ni> 10 (C + N) (However, Ni, C, and N are the amount of each component added (unit: mass%))
It is preferable that the relationship represented by is satisfied.

Further, in this ferritic Cr steel for heat-resistant precision parts, the ferrite phase is preferably 70% by volume or more.

Moreover, an additive component is the mass%,
Mo: 5 × 10 ⁻¹ to 5%,
W: 5 × 10 ⁻¹ to 1 × 10%,
V: 5 × 10 ⁻² to 4 × 10 ⁻¹ %,
Nb: 1 × 10 ⁻² to 1 × 10 ⁻¹ %,
Co: 1 × 10 ⁻¹ to 1 × 10%, or B: 2 × 10 ⁻³ to 4 × 10 ⁻³ %
It is preferable that any one or two or more of carbides, nitrides or intermetallic compounds are precipitated in the crystal grains.

Moreover, in this ferritic Cr steel for heat-resistant precision parts, the addition amount of Mo and W is
Mo + 0.5W ≧ 3.0 mass% (however, Mo and W are addition amounts of each component (unit is mass%))
It is preferable that the relationship represented by is satisfied.

The ferritic Cr steel for heat-resistant precision parts of the present invention is a ferritic Cr steel for heat-resistant precision parts containing 13 mass% or more and 30 mass% or less of Cr, and has a thermal expansion in a temperature range from room temperature to 800 ° C. The coefficient is 15 × 10 ⁻⁶ or less, the minimum creep rate at 700 ° C. and a stress of 100 MPa is 1 × 10 ⁻⁴ / h or less.

The method for producing a ferritic Cr steel for heat-resistant precision parts according to the present invention is a method for producing a ferritic Cr steel for precision parts having heat resistance, and the ferritic Cr steel having the above chemical composition is 850 to 1200 ° C. After being hot-worked within the temperature range and molded into a predetermined shape, it is annealed in a temperature range of 1000 to 1250 ° C. and then cooled to 400 ° C. or less at a cooling rate of 100 ° C./min or more. And

The heat-resistant precision component of the present invention is characterized by being formed from the above-described ferritic Cr steel for heat-resistant precision components.

The heat-resistant precision component can be any one of a turbine rotor, a disk, and a blade.

The method for producing a heat-resistant precision component according to the present invention comprises hot-working a ferritic Cr steel having the above chemical composition within a temperature range of 850 to 1200 ° C. and forming it into a part shape, and then a temperature range of 1000 to 1250 ° C. An annealing heat treatment is performed in the inside, and then it is cooled to 400 ° C. or lower at a cooling rate of 100 ° C./min or higher.

According to the present invention, a ferritic Cr steel for heat-resistant precision parts and its manufacturing method, and a heat-resistant precision part and its manufacturing method, heat-resistant precision parts for mechanical structures used at high temperatures, typically turbines. As a result, high heat resistance (creep strength) is achieved while maintaining the best low thermal expansion.

It is a graph which shows the influence of the cooling rate which has on the creep rupture time in 650 degreeC. It is a graph which shows the creep test result in 650 degreeC. It is a graph which shows the relationship between the creep rate in 700 degreeC and stress 100MPa, and time. It is a graph which shows the relationship between the creep rate and time at 750 ° C. and a stress of 50 MPa. It is a graph which shows the creep rupture time in 750 degreeC. It is a graph which shows the temperature dependence of a linear expansion coefficient.

The ferritic Cr steel for heat-resistant precision parts of the present invention has excellent high temperature strength, heat resistance, oxidation resistance and high toughness even at high temperatures exceeding 650 ° C. (hereinafter, temperature display is in units of 50 ° C.). However, it is a material that can be used for parts of a mechanical structure such as a turbine that can withstand long-term use under high temperature and high pressure and the strength reduction is suppressed.

This ferritic Cr steel for heat-resistant precision parts is obtained by hot working a steel ingot of ferritic Cr steel within a temperature range of 850 to 1200 ° C. and forming it into a predetermined shape, and then within a temperature range of 1000 to 1250 ° C. It is manufactured by annealing and then cooling to 400 ° C. or lower at a cooling rate of 100 ° C./min or higher.

The temperature during hot working such as hot forging is 850 to 1200 ° C, preferably 950 to 1150 ° C, more preferably 1000 to 1100 ° C. When the upper limit temperature is exceeded, the ductility may be drastically reduced. When the upper limit temperature is exceeded, deformation resistance may increase, and defects such as cracks may occur due to processing.

The temperature at the time of the annealing annealing is 1000 to 1250 ° C., preferably 1000 to 1200 ° C., more preferably 1050 to 1200 ° C. If the upper limit temperature is exceeded, the crystal grains may be significantly coarsened, and the toughness, ductility, weldability, etc. of the steel may be impaired. On the other hand, if the temperature is lower than the lower limit temperature, the solution cannot be completely formed and sufficient strength characteristics may not be exhibited.

Also, at a temperature of 400 ° C. or higher, the second phase such as carbides, nitrides, and intermetallic compounds precipitates at a high rate, so that the second phase may precipitate during cooling from the annealing temperature. Therefore, in order to control the precipitation of the second phase, after the annealing heat treatment, the cooling rate to 400 ° C. or less is set to 100 ° C./min or more, preferably 120 ° C./min or more, more preferably 150 ° C./min or more. is there. If it is less than the lower limit, a coarse second phase precipitates at the grain boundaries during cooling, and it becomes difficult to disperse and precipitate the fine second phase within the crystal grains. The phase precipitation state cannot be controlled and sufficient strength may not be exhibited.

Ferritic Cr steel for heat-resistant precision parts manufactured in this way has a linear expansion coefficient of 15 × 10 ⁻⁶ or less in the temperature range from room temperature to 850 ° C. The amount of thermal expansion and contraction at the time of starting and stopping increases, and it becomes difficult to manufacture heat-resistant precision parts with high dimensional accuracy.

The ferritic Cr steel for heat-resistant precision parts has a minimum creep rate of 1.0 × 10 ⁻⁴ / h or less at 700 ° C. and a stress of 100 MPa, preferably 1.0 × 10 ^−5. / h or less. If the minimum creep speed exceeds the upper limit, the amount of creep deformation due to the load generated during operation increases in the turbine, and the rotating blades (blades) and stationary components (vanes) and containers (casing) ) May come into contact with the product and cause problems such as damage.

Furthermore, the ferritic Cr steel for heat-resistant precision parts preferably has a creep rupture time of 750 ° C., stress 80 MPa, 1,000 hr or more, 750 ° C., stress 50 MPa, 5,000 hr or more, and 750 ° C., stress 30 MPa. 10,000 hours or more. When the creep rupture time is less than the lower limit, the turbine has a short creep rupture life due to a load generated during operation, and it may be difficult to ensure a practically sufficient creep rupture life.

A ferritic Cr steel before forming such as a steel ingot to be hot-worked is a ferritic Cr steel having a chemical composition adjusted, the so-called ferritic high Cr steel having the following components (described below). % Means mass%).
(1) C: 1 × 10 ⁻³ to 1 × 10 ⁻¹ %
C needs to be added in an amount of 1 × 10 ⁻³ % or more in order to improve the creep strength. On the other hand, since excessive addition reduces toughness, the upper limit of the amount of C added is set to 1 × 10 ⁻¹ %. When C is added in an amount of 1 × 10 ⁻² % or more, Ni> 10 (C + N) is preferable. In this formula, Ni, C and N indicate the amount of each component added (unit: mass%).
(2) Cr: 13-30%
It is indispensable that the amount of Cr added is 13% or more. In practice, it is preferable that 70% by volume or more of the ferrite phase is secured and that 13.5% or more is added to improve oxidation resistance. . When the amount of Cr exceeds 30%, the toughness is significantly lowered, so the upper limit of the amount of Cr is 30%.
(3) N: 1 × 10 ⁻³ to 1 × 10 ⁻¹ %
N needs to be added in an amount of 1 × 10 ⁻³ % or more in order to improve the creep strength. On the other hand, since excessive addition reduces toughness, the upper limit of the amount of N added is set to 1 × 10 ⁻¹ %. When N is added in an amount of 1 × 10 ⁻² % or more, it is preferable that Ni> 10 (C + N) as in the case of C.
(4) Ni: 1 × 10 ⁻¹ to 2.5%
Ni needs to be added in an amount of 1 × 10 ⁻¹ % or more in order to improve toughness. When the addition amount of at least one or both of C and N is 1 × 10 ⁻² % or more, the addition amount of Ni preferably satisfies Ni> 10 (C + N) as described above to ensure toughness. . On the other hand, excessive addition reduces the volume fraction of the ferrite phase, so the upper limit of the amount of Ni added is 2.5%.

As shown in Table 2 below, comparative steel in which the addition amount of Ni is Ni ≦ 10 (C + N) (where Ni, C, and N indicate the addition amount of each component (unit: mass%)) 7 and 8 have a small Charpy impact value regardless of the difference in cooling rate. On the other hand, the water-cooled materials of the inventive steels 1 to 4 that also satisfy the relationship represented by Ni> 10 (C + N) have sufficiently large Charpy impact values compared to the comparative steels 7 and 8.

Ferritic Cr steel can be strengthened by controlled precipitation of one or more of carbides, nitrides or intermetallic compounds, that is, fine dispersion precipitation within crystal grains, and creep strength It becomes effective to raise. For this reason, the ferritic Cr steel allows the addition of the following components in addition to the above components in its chemical composition.
(5) Mo: 5 × 10 ⁻¹ to 5%
Mo is a chemical component effective for precipitation of intermetallic compounds, and can increase creep strength. The addition amount can be 5 × 10 ⁻¹ % or more. On the other hand, since excessive addition may reduce toughness, the upper limit of the amount of Mo added is preferably 5%.
(6) W: 5 × 10 ⁻¹ to 1 × 10%
W, like Mo, is a chemical component effective for precipitation of intermetallic compounds, and can increase the creep strength. The addition amount can be 5 × 10 ⁻¹ % or more. On the other hand, since excessive addition may reduce toughness, the upper limit of the amount of W added is preferably 1 × 10%.

In addition, about Mo and W, addition amount can satisfy | fill the relationship shown by Mo + 0.5W> = 3.0% so that the precipitation amount of an intermetallic compound may fully be ensured (in Formula, Mo and W represent respective addition amounts (unit: mass%)).
(7) V: 5 × 10 ⁻² to 4 × 10 ⁻¹ %
V forms carbides and nitrides effective for improving the creep strength. The addition amount can be 5 × 10 ⁻² % or more, but excessive addition is not always effective for the formation of carbides and nitrides, so the upper limit of the addition amount is 4 × 10 ⁻¹ %. Is preferred.
(8) Nb: 1 × 10 ⁻² to 1 × 10 ⁻¹ %
Nb, like V, forms carbides and nitrides that are effective in improving creep strength. The addition amount can be 1 × 10 ⁻² % or more, but excessive addition is not always effective for the formation of carbides and nitrides, so the upper limit of the addition amount is 1 × 10 ⁻¹ %. Is preferred.
(9) Co: 1 × 10 ⁻¹ to 1 × 10%
Co is an effective component for improving the creep strength by refining precipitated carbides, nitrides and intermetallic compounds. The addition amount can be 1 × 10 ⁻¹ % or more, but excessive addition may reduce the volume fraction of the ferrite phase, so the upper limit of the addition amount is preferably 1 × 10%. .
(10) B: 2 × 10 ⁻³ to 4 × 10 ⁻³ %
B is a component effective for refining and stabilizing precipitates and strengthening grain boundaries. The addition amount can be 2 × 10 ⁻³ % or more. On the other hand, excessive addition may generate boron nitride and may not always be effective in improving the creep strength, so the upper limit of the amount of B is preferably 4 × 10 ⁻³ %.
(11) Mn: 5 × 10 ⁻² to 8 × 10 ⁻¹ %
It is an effective component as a deoxidizing material. The addition amount can be 5 × 10 ⁻² % or more. On the other hand, since excessive addition is harmful to strength and toughness, the upper limit of the amount of Mn added is preferably 8 × 10 ⁻¹ %.
(12) Si: 5 × 10 ⁻² to 5 × 10 ⁻¹ %
It is an effective component as a deoxidizing material. The addition amount can be 5 × 10 ⁻² % or more. On the other hand, excessive addition promotes coarsening of precipitates and lowers strength, so the upper limit of Si addition amount is preferably 5 × 10 ⁻¹ %.

And the chemical composition of ferritic Cr steel for heat-resistant precision parts consists of Fe and inevitable impurities.

Also, it is preferable that the ferrite-based Cr steel for heat-resistant precision parts has 70% by volume or more of ferrite phase to improve creep strength. The tempered martensite structure is unstable at high temperatures, but the ferrite phase has high structure stability at high temperatures. As shown in Table 2, when the inventive steels 2 to 4 are cooled in the furnace, the cooling rate after the annealing heat treatment is slow, so the volume fraction of the ferrite phase is less than 70%. When the cooling rate up to 100 ° C./min or higher, the volume fraction of the ferrite phase becomes 70% or higher. For this reason, as shown in FIG. 1, the water-cooled materials of the inventive steels 2 to 4 show a creep rupture time that is about 10 times longer than that of the furnace-cooled material.

In addition, as shown in FIG. 2, the steels 1 to 4 of the present invention have creep rupture compared to the comparative steels 9 to 15 in which the added amount of Cr is less than 13% and the volume fraction of the ferrite phase is less than 70%. Long time.

Examples are shown below.

In the examples, various characteristics were measured on the assumption that a round bar is a part. It is easily predicted and understood that precision parts such as rotors, discs, blades, etc., manufactured from the above-mentioned ferritic Cr steel, have the same characteristics as the ferritic Cr steel that is the material. Can do.

Diameters of round bars of steels 1 to 8 (invention steels 1 to 6 and comparative steels 7 and 8) having the chemical composition shown in Table 1 were hot forged at a temperature range of 850 to 1150 ° C. with a 10 kg steel ingot. After forming to 15 mm and annealing heat treatment at 1200 ° C., each was produced by cooling by furnace cooling or water cooling.

Table 1 also shows the chemical compositions of steels 9 to 15 (comparative steels), which are existing ferritic heat resistant steels.

The Charpy impact test was performed at 100 ° C. on the prepared test pieces. The results are shown in Table 2.

The comparative steels 7 and 8 which have a small amount of added Ni and are outside the range of the steel of the present invention have a small impact value regardless of the cooling rate after annealing heat treatment, whereas the steels of the present invention 1 to 4 are cooled. In the case of furnace cooling at a low speed, the impact value is small, but in water cooling at a high cooling speed, the impact value is 300 J / cm ² or more, which is larger than that of the furnace cooling material and comparative steels 7 and 8.

FIG. 1 is a graph showing the influence of the cooling rate on the creep rupture time at 650 ° C. of inventive steels 2-4. It can be seen that the water-cooled material having a high cooling rate has a creep rupture time approximately 10 times longer than that of the furnace-cooled material having a low cooling rate.

Table 3 shows the measurement data that created FIG.

As a condition required for the cooling rate, after annealing heat treatment within a temperature range of 1000 to 1250 ° C., the precipitation is continued until the temperature reaches 400 ° C., which is a low temperature at which carbide, nitride and intermetallic compounds do not substantially precipitate. It is confirmed that the cooling is performed at a high cooling rate capable of suppressing the above-mentioned, specifically, at 100 ° C./min or more.

FIG. 2 is a graph showing the results of a creep test at 650 ° C.

It can be seen that the inventive steels 1 to 4 have higher creep strength than the comparative steels 9 to 15 in which the addition amount of Cr is less than 13% by mass and the volume fraction of the ferrite phase is less than 70%.

Table 4 shows the measurement data that created FIG.

FIG. 3 is a graph showing the relationship between creep rate and time at 700 ° C. and stress of 100 MPa.

It can be seen that the steels 2 and 4 of the present invention have a creep rate as small as about 1000 times that of the comparative steels 9 to 11, and the creep rupture time is about 100 times longer.

Table 5 shows the minimum creep rate obtained from FIG. In the steels 2 and 4 of the present invention, the minimum creep rate is 1.0 × 10 ⁻⁴ / h or less, and 1.0 × 10 ⁻⁵ / h or less.

FIG. 4 is a graph showing the relationship between creep rate and time at 750 ° C. and a stress of 50 MPa.

The invention steel 4 was not broken and the test was in progress. In addition, it can be seen that the steels 2 and 4 of the present invention both have a creep rate as small as 1/100 or less, and the creep rupture time is about 100 times longer than that of the comparative steels 9 and 13.

Table 6 shows the measurement data that created FIG.

FIG. 5 is a graph showing the creep rupture time at 750 ° C.

Invented steels 2 and 4 were not broken in the tests at stresses of 50 MPa and 30 MPa, and the test was in progress. Further, in the test at a stress of 80 to 50 MPa, the creep rupture time of the inventive steels 2 and 4 is about 100 times longer than the rupture time of the comparative steels 9 to 15, and the austenitic heat resistant steels 21 to It can be seen that it is longer than SUS316, which is 28. Furthermore, it can be seen that the creep rupture time is about the same as that of SUS316 in steels 2 and 4 of the present invention even at a stress of 30 MPa.

Table 7 shows the measurement data that created FIG.

FIG. 6 is a graph showing the temperature dependence of the linear expansion coefficient. It is the result of having compared the linear expansion coefficient of this invention steel and practical heat-resistant material.

The inventive steels 2 and 4 were heated from room temperature to 1000 ° C. at a rate of 1000 ° C./h, and the thermal expansion at that time was measured to obtain the linear expansion coefficient at each temperature. The linear expansion coefficient of the practical heat-resistant material is a value specified in the boiler pressure vessel standard of the American Society of Mechanical Engineers (ASME).

Table 8 shows the measurement data that created FIG.

In the steels 2 and 4 of the present invention, the linear expansion coefficient is 15 × 10 ⁻⁶ or less in the temperature range from room temperature to 850 ° C., and it has low thermal expansion equivalent to or higher than that of ferritic steel. I understand.

According to the present invention, a ferritic Cr steel having low heat expansion and improved heat resistance (creep strength) is realized. This ferritic Cr steel realizes heat-resistant precision parts for mechanical structures such as turbines that are used at high temperatures exceeding 650 ° C.

Claims

Ferritic Cr steel for precision parts with heat resistance, whose chemical composition is mass%,
Cr: 13-30%
Ni: 1 × 10 −1 to 2.5%,
C: 1 × 10 −3 to 1 × 10 −1 %, and N: 1 × 10 −3 to 1 × 10 −1 %
, A ferritic Cr steel for precision machine parts, characterized in that the additive component and inevitable impurities are allowed to be contained, the balance being Fe, and a ferrite phase being formed.
When either one or both of the addition amount of C is 1 × 10 −2 mass% or more or the addition amount of Ni is 1 × 10 −2 mass% or more, the addition amount of Ni is
Ni> 10 (C + N) (However, Ni, C, and N are the amount of each component added (unit: mass%))
The ferritic Cr steel for heat-resistant precision parts according to claim 1, wherein the relationship represented by:
Ferrite-based Cr steel for heat-resistant precision parts according to claim 1 or 2, wherein the ferrite phase is 70% by volume or more.
Additive component is mass%,
Mo: 5 × 10 −1 to 5%,
W: 5 × 10 −1 to 1 × 10%,
V: 5 × 10 −2 to 4 × 10 −1 %,
Nb: 1 × 10 −2 to 1 × 10 −1 %,
Co: 1 × 10 −1 to 1 × 10%, or B: 2 × 10 −3 to 4 × 10 −3 %
3. One or more of the above, wherein one or more of carbides, nitrides or intermetallic compounds are precipitated in the crystal grains. 4. Ferritic Cr steel for heat resistant precision parts.
The amount of addition of Mo and W is
Mo + 0.5W ≧ 3.0 mass% (however, Mo and W are addition amounts of each component (unit is mass%))
5. The ferritic Cr steel for heat-resistant precision parts according to claim 4, wherein the relationship represented by:
Ferritic Cr steel for heat-resistant precision parts containing 13 to 30% by mass of Cr, having a thermal expansion coefficient of 15 × 10 −6 or less in a temperature range from room temperature to 800 ° C., 700 ° C., stress A ferritic Cr steel for heat-resistant precision parts, characterized in that the minimum creep rate at 100 MPa is 1 × 10 −4 / h or less.
A method for producing a ferritic Cr steel for precision parts having heat resistance, wherein the ferritic Cr steel having the chemical composition according to claim 1 is hot-worked within a temperature range of 850 to 1200 ° C. to obtain a predetermined shape. Of ferritic Cr steel for heat-resistant precision parts, characterized by being annealed in a temperature range of 1000 to 1250 ° C. and then cooled to 400 ° C. or lower at a cooling rate of 100 ° C./min or higher. Production method.
A heat-resistant precision part, characterized in that it is formed from the ferritic Cr steel for heat-resistant precision parts according to claim 1.
The heat-resistant precision component according to claim 8, wherein the heat-resistant precision component is any one of a turbine rotor, a disk, and a blade.
The ferritic Cr steel having the chemical composition according to claim 1 is hot-worked in a temperature range of 850 to 1200 ° C., formed into a part shape, and then annealed in a temperature range of 1000 to 1250 ° C., Next, a method for producing a heat-resistant precision part, which is cooled to 400 ° C. or lower at a cooling rate of 100 ° C./min or higher.