JP3246376B2 - Columnar crystal Ni-base heat-resistant alloy large casting with excellent high-temperature intergranular corrosion resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature grain boundary corrosion resistance, and particularly to a columnar crystal Ni-base heat-resistant alloy casting excellent in high temperature grain boundary corrosion resistance. The present invention relates to a large turbine blade used as a turbine moving / stationary blade of a gas turbine and a moving blade of a high-temperature blower.

[0002]

2. Description of the Related Art It is known that turbine blades and vanes of a gas turbine and blades of a high-temperature blower are made of a Ni-base heat-resistant alloy casting.
Japanese Patent Publication No. 395 discloses a turbine operation and a stationary blade of a gas turbine,
As a Ni-base heat-resistant alloy for making a rotor blade of a high-temperature blower, (a) C
r: 13.1 to 15.0%, Co: 8.5 to 10.5
%, Mo: 1.0 to 3.5%, W: 3.5 to 4.5%,
Ta: 3.0 to 5.5%, Al: 3.5 to 4.5%, T
i: 2.0 to 3.2%, C: 0.06 to 0.12%,
B: 0.005 to 0.025%, Zr: 0.010 to
0.050%, Mg and / or Ca: 1 to 100 p
pm, a Ni-base heat-resistant alloy excellent in high-temperature strength, high-temperature oxidation resistance and high-temperature corrosion resistance, having a composition consisting of Ni and unavoidable impurities, (b) Cr: 13.1-1
5.0%, Co: 8.5 to 10.5%, Mo: 1.0 to
3.5%, W: 3.5-4.5%, Ta: 3.0-5.0.
5%, Al: 3.5 to 4.5%, Ti: 2.0 to 3.2
%, C: 0.06 to 0.12%, B: 0.005 to 0.
025%, Zr: 0.010 to 0.050%, and
High-temperature strength, high-temperature oxidation resistance and high-temperature corrosion resistance containing Hf: 0.2 to 1.5%, containing Mg and / or Ca: 1 to 100 ppm, and the balance being Ni and unavoidable impurities. Excellent Ni-base heat-resistant alloy, (c)
Cr: 13.1 to 15.0%, Co: 8.5 to 10.5
%, Mo: 1.0 to 3.5%, W: 3.5 to 4.5%,
Ta: 3.0 to 5.5%, Al: 3.5 to 4.5%, T
i: 2.0 to 3.2%, C: 0.06 to 0.12%,
B: 0.005 to 0.025%, Zr: 0.010 to
0.050%, Mg and / or Ca: 1 to 100 p
pm, Hf: 0.2-1.5%, Pt: 0.02-0.5%, Rh: 0.0
High-temperature strength, high-temperature oxidation resistance, containing one or two or more of 2 to 0.5% and Re: 0.02 to 0.5%, with the balance being Ni and unavoidable impurities. Ni-base heat-resistant alloy with excellent high-temperature corrosion resistance, (d) Cr: 1
3.1 to 15.0%, Co: 8.5 to 10.5%, M
o: 1.0 to 3.5%, W: 3.5 to 4.5%, Ta:
3.0 to 5.5%, Al: 3.5 to 4.5%, Ti:
2.0-3.2%, C: 0.06-0.12%, B:
0.005 to 0.025%, Zr: 0.010 to 0.0
50%, Mg and / or Ca: 1 to 100 ppm, Hf: 0.2 to 1.5%, Pt: 0.02 to 0.5%, Rh: 0.02 to 0 .5
%, Re: 0.02 to 0.5%, one or more of which have a balance of Ni and unavoidable impurities, and have excellent high-temperature strength, high-temperature oxidation resistance and high-temperature corrosion resistance. Ni-based heat-resistant alloys, etc. are described.

On the other hand, it is also known that the turbine blades and vanes of a gas turbine and the blades of a high-temperature blower are made of a columnar crystal Ni-base heat-resistant alloy casting. In order to produce the columnar crystal Ni-base heat-resistant alloy casting, a normal one-way solidification device is used. In this unidirectional solidification apparatus, the inside of the vacuum chamber is evacuated, and the molten Ni-base alloy melted in the melting furnace is
After pouring into a mold fixed on a chill plate and heated to a temperature of 1480 to 1530 ° C., the mold is pulled down through a water-cooled chill ring and the chill plate is pulled down at a speed of 200 to 350 mm / h. A long columnar crystal Ni-base heat-resistant alloy casting is produced by growing crystals.

[0004]

In recent years, as the size of a gas turbine has increased, the size of turbine blades installed therein has also increased. However, when a large-sized turbine blade made of a columnar-crystal Ni-base heat-resistant alloy casting, particularly a columnar-crystal Ni-base heat-resistant alloy casting is manufactured from a conventional Ni-base heat-resistant alloy, the crystal grains become coarse and segregation of the alloy component becomes large. At the grain boundaries where segregation is greatest, intergranular corrosion significantly progresses,
The high-temperature intergranular corrosion resistance was greatly reduced, and the reliability and life of large turbine blades made of columnar crystal Ni-base heat-resistant alloy casting were reduced.

[0005]

The inventors of the present invention have conducted intensive studies to improve the high-temperature intergranular corrosion resistance of large turbine blades. As a result, the amount of Zr added to the Ni-based alloy was limited to a very small amount, and Cr: 12.0 to 14.3%, Co: 8.5 to 1
1.0%, Mo: 1.0 to 3.5%, W: 3.5 to 6.
2%, Ta: 3.0 to 5.5%, Al: 3.5 to 4.5
%, Ti: 2.0 to 3.2%, C: 0.04 to 0.12
%, B: 0.005 to 0.05%, Zr: 0.001 to
5 ppm, the balance being limited to a composition consisting of Ni and unavoidable impurities, and lowering the chill plate while injecting a molten metal obtained by melting a Ni-based alloy having such a composition into a mold of a one-way solidification apparatus. The columnar crystal Ni-base heat-resistant alloy casting was heated to 1800 to 1265 ° C and 900 to 1600 atm.
HIP of time retention is applied, 1200-
A solution heat treatment is performed at 1265 ° C. for 2 to 5 hours, and further maintained at 950 to 1080 ° C. for 2 to 10 hours.
When subjected to aging heat treatment at 60 to 870 ° C. for 16 to 24 hours, columnar crystal Ni having better high-temperature intergranular corrosion resistance than before is obtained.
A base heat-resistant alloy casting was obtained, and it was found that large turbine blades made of columnar crystal Ni-base heat-resistant alloy casting having excellent high-temperature intergranular corrosion resistance have characteristics superior to conventional high-temperature intergranular corrosion resistance. Thus, the present invention has been reached.

The present invention has been made based on such findings, and (1) Cr: 12.0 to 14.3%,
Co: 8.5 to 11.0%, Mo: 0.5 to 4%, W:
3.5 to 6.2%, Ta: 3.0 to 5.5%, Al:
3.5-4.5%, Ti: 2.0-3.2%, C: 0.
04-0.12%, B: 0.005-0.05%, Z
r: 0.001 to 5 ppm, and the balance is characterized by a columnar crystal Ni-base heat-resistant alloy large casting excellent in high-temperature intergranular corrosion resistance and having a composition consisting of Ni and unavoidable impurities.

[0007] The composition of the Ni-base alloy constituting the columnar-crystal Ni-base heat-resistant alloy large casting having excellent high-temperature intergranular corrosion resistance of the present invention is, in terms of% by weight, Cr: 13 to 14% and Co: 9.4.
-10.6%, Mo: 1.2-2.0%, W: 4.2-
5.8%, Ta: 4.0 to 5.2%, Al: 3.8 to
4.4%, Ti: 2.2 to 3.0%, C: 0.05 to
0.09%, B: 0.008 to 0.03%, Zr: 0.
It is more preferable that the composition contains 0.1 to 1 ppm, with the balance being Ni and unavoidable impurities.

[0008] The columnar crystal Ni-base heat-resistant alloy excellent in high-temperature intergranular corrosion resistance of the present invention is particularly suitable as a material for large turbine blades. Therefore, the present invention provides (3) Cr: 12.
0 to 14.3%, Co: 8.5 to 11.0%, Mo:
1.0 to 3.5%, W: 3.5 to 6.2%, Ta: 3.
0 to 5.5%, Al: 3.5 to 4.5%, Ti: 2.0
To 3.2%, C: 0.04 to 0.12%, B: 0.00
A large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting having a composition of 5 to 0.05% and Zr: 0.001 to 5 ppm, the balance being Ni and unavoidable impurities and having excellent high-temperature intergranular corrosion resistance; It is characterized by the following.

[0009] The Ni constituting a large turbine blade made of a columnar crystal Ni-based heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance according to the present invention.
The component composition of the base alloy is, in weight%, Cr: 13-14%,
Co: 9.4 to 10.6%, Mo: 1.2 to 2.0%,
W: 4.2-5.8%, Ta: 4.0-5.2%, A
l: 3.8 to 4.4%, Ti: 2.2 to 3.0%, C:
0.05-0.09%, B: 0.008-0.03%,
More preferably, Zr contains 0.01 to 1 ppm, and the balance has a composition composed of Ni and unavoidable impurities.

The columnar crystal Ni-base heat-resistant alloy excellent in high-temperature intergranular corrosion resistance of the present invention comprises Mg and / or Ca: 1-1.
00 ppm, and Pt: 0.02 to
0.5%, Rh: 0.02 to 0.5%, Re: 0.02
One or more of 0.5% to 0.5%, or both of them may be contained.

Therefore, the present invention provides (4) Cr: 12.
0 to 14.3%, Co: 8.5 to 11.0%, Mo:
0.5-4%, W: 3.5-6.2%, Ta: 3.0-
5.5%, Al: 3.5-4.5%, Ti: 2.0-
3.2%, C: 0.04 to 0.12%, B: 0.005
~ 0.05%, containing Zr: 0.001-5ppm,
Furthermore, a columnar crystal Ni-based heat-resistant alloy large-sized casting excellent in high-temperature intergranular corrosion resistance having a composition comprising Mg and / or Ca: 1 to 100 ppm and a balance of Ni and unavoidable impurities, (5) Cr: 12. 0-14.3%, Co:
8.5 to 11.0%, Mo: 0.5 to 4%, W: 3.5
-6.2%, Ta: 3.0-5.5%, Al: 3.5-
4.5%, Ti: 2.0 to 3.2%, C: 0.04 to
0.12%, B: 0.005 to 0.05%, Zr: 0.
001 to 5 ppm, and Pt: 0.02 to
0.5%, Rh: 0.02 to 0.5%, Re: 0.02
A large cast of a columnar crystal Ni-base heat-resistant alloy excellent in high-temperature intergranular corrosion resistance, having one or two or more of 0.5% and a balance of Ni and unavoidable impurities;
(6) Cr: 12.0 to 14.3%, Co: 8.5 to 1
1.0%, Mo: 0.5 to 4%, W: 3.5 to 6.2
%, Ta: 3.0 to 5.5%, Al: 3.5 to 4.5
%, Ti: 2.0 to 3.2%, C: 0.04 to 0.12
%, B: 0.005 to 0.05%, Zr: 0.001 to
5 ppm, and further contains Mg and / or Ca: 1
-100 ppm, and further Pt: 0.02-0.
5%, Rh: 0.02-0.5%, Re: 0.02-
One or more of 0.5%, with the balance being N
The present invention is characterized by a columnar crystal Ni-base heat-resistant alloy large casting having a composition comprising i and unavoidable impurities and having excellent high-temperature intergranular corrosion resistance.

The columnar-crystal Ni-base heat-resistant alloy of the present invention, which is excellent in high-temperature grain boundary corrosion resistance and contains one or more of Mg and / or Ca, Pt, Rh and Re, is particularly large-sized turbine. Suitable as a material for wings. Therefore,
The present invention relates to (7) Cr: 12.0 to 14.3%, C
o: 8.5 to 11.0%, Mo: 1.0 to 3.5%,
W: 3.5-6.2%, Ta: 3.0-5.5%, A
l: 3.5 to 4.5%, Ti: 2.0 to 3.2%, C:
0.04 to 0.12%, B: 0.005 to 0.05%,
Zr: 0.001 to 5 ppm, Mg and / or Ca: 1 to 100 ppm, the balance being N
The balance having a composition consisting of i and unavoidable impurities is Ni
And a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting having a composition composed of unavoidable impurities and having excellent high-temperature intergranular corrosion resistance, (8) Cr: 12.0 to 14.3%, Co: 8.5
１11.0%, Mo: 1.0-3.5%, W: 3.5-
6.2%, Ta: 3.0 to 5.5%, Al: 3.5 to
4.5%, Ti: 2.0 to 3.2%, C: 0.04 to
0.12%, B: 0.005 to 0.05%, Zr: 0.
001 to 5 ppm, and Pt: 0.02 to
0.5%, Rh: 0.02 to 0.5%, Re: 0.02
Of at least 0.5%, and the remainder having a composition consisting of Ni and unavoidable impurities is N.
large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance having a composition consisting of i and unavoidable impurities, (9) Cr: 12.0 to 14.3%, Co: 8.
5 to 11.0%, Mo: 1.0 to 3.5%, W: 3.5
-6.2%, Ta: 3.0-5.5%, Al: 3.5-
4.5%, Ti: 2.0 to 3.2%, C: 0.04 to
0.12%, B: 0.005 to 0.05%, Zr: 0.
001 to 5 ppm, further contains Mg and / or Ca: 1 to 100 ppm, and further contains Pt: 0.0
2 to 0.5%, Rh: 0.02 to 0.5%, Re: 0.
The composition contains one or more of 02 to 0.5%, and the balance has a composition consisting of Ni and unavoidable impurities. The balance has a composition consisting of Ni and unavoidable impurities. It is characterized by a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting.

Next, the alloy composition of the columnar crystal Ni-base heat-resistant alloy large casting excellent in high temperature grain boundary corrosion resistance and the columnar crystal Ni-base heat resistant alloy casting excellent in high temperature grain boundary corrosion resistance of the present invention is described. Will be described in detail.

In a Cr industrial gas turbine, oxidation resistance and corrosion resistance at high temperatures are required because it comes into contact with combustion gas containing oxidizing and corrosive substances generated by combustion. Cr is an element that imparts oxidation resistance and corrosion resistance to the alloy, and the effect is remarkable as the Cr content in the alloy is increased. However, if the Cr content is less than 12.0%, the effect is small.
On the other hand, the columnar crystal Ni of the present invention, which has excellent high-temperature intergranular corrosion resistance,
In large base heat-resistant alloy castings, Co, Mo, W, Ta and the like are also added.
It is not preferable to contain more than 4.3%. Therefore, the Cr content is set to 12.0 to 14.3%. As described above, the Cr content in the Ni-base heat-resistant alloy for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance of the present invention may be 13 to 14%. More preferred.

Co Co increases the limit (solid solubility limit) of solid solution of Ti, Al, Ta and the like at a high temperature, and finely disperses the γ 'phase (Ni ₃ (Ti, Al, Ta)) by heat treatment. The amount of Co must be 8.5% or more because it has an effect of improving the strength of a large-sized columnar crystal Ni-base heat-resistant alloy which is precipitated and has excellent high-temperature intergranular corrosion resistance. If the amount exceeds 11.0%, Cr, Mo, W, Ta, A
The Co content is 8. because the balance with other elements such as l and Ti is lost and the ductility is reduced due to the precipitation of a harmful phase.
It was set to 5 to 11.0%. The Co content in the Ni-base heat-resistant alloy for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance of the present invention is 9.4.
More preferably, it is で 10.6%.

Mo Mo has a function of increasing the high-temperature strength by forming a solid solution in the base material, and has an effect of contributing to the high-temperature strength by precipitation hardening. On the other hand, if it is added in excess of 3.5%, ductility due to precipitation of a harmful phase is inhibited, so that Mo: 1.0 to 3.5.
%. Ni for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting having excellent high-temperature intergranular corrosion resistance according to the present invention.
The Mo content in the base heat-resistant alloy is more preferably 1.2 to 2.0%.

WW has the effect of solid solution strengthening and precipitation hardening similarly to Mo, and has the effect of contributing to the provision of high-temperature strength, but the amount is 3.5.
% Or more, if too much, harmful phases are precipitated and W itself is an element having a large specific gravity, so that the specific gravity of the entire alloy becomes large. When casting large columnar crystal castings with excellent intergranular corrosion resistance, fleckle defects are generated and the cost is increased. Therefore, the content is 3.5 to 6.2%. did. The W content contained in the Ni-base heat-resistant alloy for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance of the present invention is more preferably 4.2 to 5.8%. preferable.

Ti Ti is an element necessary for the precipitation of the γ ′ phase to increase the high-temperature strength of the γ ′ precipitation-hardening Ni-based alloy. If less than 2.0%, the precipitation strengthening of the γ ′ phase is insufficient. If the required strength cannot be satisfied, and if it is added in excess of 3.2%, the amount of precipitation becomes too large, impairs ductility, and a columnar crystal large casting excellent in high-temperature intergranular corrosion resistance. Is unfavorable because the reaction with the irregular shape becomes violent when casting is performed, and the casting surface is deteriorated. Therefore, the Ti content is set to 2.0 to 3.2%. As described above, the content of Ti contained in the Ni-base heat-resistant alloy for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance according to the present invention is 2.2 to 3.0.
More preferably, it is 0%.

Al Al is an element exhibiting the same effect as Ti. It forms a γ 'phase, increases the high-temperature strength, and has an effect of contributing to oxidation resistance and corrosion resistance at high temperatures. The amount is 3.5
%, Or more than 4.5%, the addition of too much may hinder the ductility.
The l content was determined to be 3.5 to 4.5%. The Al content in the Ni-base heat-resistant alloy for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance according to the present invention is more preferably 3.8 to 4.4%. preferable.

Ta Ta contributes to improvement of high-temperature strength by solid solution strengthening and γ ′ phase precipitation hardening, and is effective at 3.0% or more. On the other hand, if added too much, the ductility decreases, so the content was made 5.5% or less. Therefore, the Ta content contained in the Ni-base heat-resistant alloy for producing a large turbine blade made of a columnar crystal Ni-base heat-resistant alloy casting excellent in high-temperature intergranular corrosion resistance of the present invention was set to 3.0 to 5.5%. Is more preferably 4.0 to 5.2%.

C forms carbides and precipitates particularly at crystal grain boundaries and dendrite boundaries to strengthen grain boundaries and dendrite boundaries, and contributes to improvement in high-temperature strength. There are, on the other hand, 0.
If added in excess of 12%, ductility is impaired, so its content was made 0.04 to 0.12%. A more preferable range of the content of C is 0.05 to 0.09%.

BB is a necessary component because it increases the bonding force at the crystal grain boundaries to strengthen the crystal boundaries and raises the high-temperature strength. However, if the content is less than 0.005%, the desired effect can be obtained. However, on the other hand, if added too much, there is a risk of inhibiting ductility, so the content was made 0.05% or less. A more preferable range of the B content is 0.008 to 0.03%.

Zr Zr is added in a small amount to increase the corrosion resistance of the crystal grain boundaries and increase the high-temperature intergranular corrosion resistance.
However, if it is added in excess of 5 ppm, a large amount of Zr segregates at the crystal grain boundaries and conversely lowers the corrosion resistance of the crystal grain boundaries and lowers the local melting temperature. The solution heat treatment temperature for dispersing cannot be increased, and igniting the local decrease in melting temperature, raising the temperature necessary for fine dispersion of the precipitation strengthening phase and performing the solution heat treatment results in "cracking" Undesirably occurs. Therefore, the content of Zr is 0.001 to 5 ppm
Determined. A more preferred range of the Zr content is 0.01
１1 ppm.

Mg and / or Ca Mg and / or Ca have a strong binding force with impurities such as oxygen and sulfur, and have an effect of preventing a decrease in ductility due to impurities such as oxygen and sulfur. Mg and / or Ca are set to 1 to 100 ppm from the point that no effect is obtained, whereas if the content exceeds 100 ppm, the bonding of the crystal grain boundaries is weakened and cracks are caused.

Pt, Rh, Re Pt, Rh, and Re have an effect of improving corrosion resistance. However, if their contents are less than 0.02%, the desired effects cannot be obtained. %, It is not preferable because further effects cannot be expected, and the price increases because of the noble metal. Therefore,
One or more of Pt, Rh, and Re are each set to 0.02 to 0.5%.

Others Although Hf is an essential component in a conventional columnar crystal Ni-base heat-resistant alloy large casting, it is not preferable to include Hf in the columnar crystal Ni-base heat-resistant alloy casting of the present invention.

In order to produce a columnar-crystal Ni-base heat-resistant alloy large casting excellent in high-temperature intergranular corrosion resistance according to the present invention, the chill plate is pulled down at a mold heating temperature of 1480 to 1530 ° C. by a unidirectional solidification apparatus, and a pull-down speed of 200 is used. A large cast of columnar crystal Ni-base heat-resistant alloy is produced by lowering at ~ 350 mm / h,
This is 900-1600 atm at 1180-1265 ° C,
Apply HIP for 1-5 hours, 1200-1265 ° C
And heat treatment for 2 to 5 hours.
After holding at -1080 ° C for 2-10 hours, 760-87
It is obtained by performing an aging heat treatment at 0 ° C. for 16 to 24 hours.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION A Ni-base heat-resistant alloy having the component composition shown in Tables 1 to 3 is prepared, and each of the Ni-base heat-resistant alloys is melted in a vacuum, and a molten metal of the Ni-base heat-resistant alloy is used in a unidirectional solidification apparatus. While casting in the mold, mold heating temperature: 1600
° C, the chill plate is pulled down at a speed of 120 mm / h.
The columnar crystal large casting plates 1 to 16 of the present invention and the conventional columnar large casting plates 17 to 20 having dimensions of 15 mm in length, 100 mm in width, and 300 mm in height were produced.

[0029]

[Table 1]The present invention columnar crystal large casting plate  element 1 2 3 4 5 6 7 8 Cr 13.1 14.0 12.5 13.5 13.3 12.2 13.3 14.2 Co 9.0 8.5 10.1 10.5 10.1 9.7 8.8 9.3 Mo 2.1 1.0 3.5 1.5 1.5 2.4 2.7 3.0 W 4.0 3.5 4.3 3.7 4.5 4.5 4.1 3.9 Ta 3.3 5.4 4.9 3.0 4.6 3.8 3.5 3.8 Al 4.0 3.5 4.3 3.7 4.1 4.5 4.1 3.9 Ti 2.7 2.3 3.2 2.5 2.7 2.9 3.0 2.8 C 0.08 0.10 0.06 0.12 0.06 0.07 0.09 0.11 B 0.011 0.009 0.007 0.015 0.010 0.013 0.012 0.010 Zr 1.3 2.6 1.2 4.3 0.05 0.005 0.1 0.6 Ca------53 10 Mg -----81-12 Pt--------Rh---------Re---------Ni Remaining Remaining Remaining Remaining Remaining Remaining Remaining Remaining % By weight, where Zr, Ca and Mg are ppm 

[0030]

[Table 2]The present invention columnar crystal large casting plate  element 9 10 11 12 13 14 15 16 Cr 13.8  12.1 14.0 13.0 13.5 12.5 13.3 14.2 Co 9.5 9.0 8.5 10.1 10.5 9.7 8.8 9.3 Mo 1.8 2.1 1.1 3.5 1.5 2.4 2.7 3.0 W 4.2 4.0 3.5 4.3 3.8 4.6 4.1 3.9 Ta 4.5 3.3 5.3 4.9 3.1 3.8 3.5 3.8 Al 4.2 4.1 3.6 4.3 3.8 4.5 4.1 3.9 Ti 2.7 2.7 2.2 3.1 2.5 2.9 3.0 2.8 C 0.08 0.08 0.10 0.07 0.12 0.07 0.09 0.11 B 0.005 0.011 0.039 0.007 0.015 0.013 0.012 0.010 Zr 19 0.3 0.8 1.9 2.3 3.6 0.03 0.7 Ca 18---25 74 34 10 Mg 72- − − 37 5 54 12 Pt − 0.05 0.1 − 0.2 0.06 0.2 0.05 Rh − 0.05 0.2 0.1 0.1 − − 0.05 Re − 0.05 − 0.3 − 0.07 0.1 0.05Ni Remaining Remaining Remaining Remaining Remaining Remaining Remaining Remaining % By weight, where Zr, Ca and Mg are ppm 

[0031]

[Table 3]

The obtained columnar crystal large casting plate of the present invention 1 to 16
In addition, the conventional columnar crystal large casting plates 17 to 20 are subjected to HIP in an Ar atmosphere at a temperature of 1180 ° C. and a temperature of 1500 atm for 2 hours, and then in a vacuum atmosphere at a temperature of 124.
After maintaining the temperature at 0 ° C. for 2 hours, a solution treatment under cooling conditions is performed with an Ar gas fan, and then, in a vacuum atmosphere, at a temperature of 1: 1.
After maintaining the temperature at 050 ° C. for 5 hours, it was cooled with an Ar gas fan. Subsequently, after maintaining the temperature at 870 ° C. for 18 hours in a vacuum atmosphere, a second-stage aging treatment was performed with the Ar gas fan.

The columnar-crystal large-sized cast sheets 1 and 16 of the present invention and the conventional columnar-shaped large-sized cast sheet 1 which have been subjected to the HIP and heat treatment.
7 to 20 are cut out by machining to have a diameter of 10 mm,
A test piece having a length of 20 mm was prepared, and the obtained test piece was melted at a temperature of 950 ° C. (Na ₂ SO ₄ : 20 wt.
%, NaCl: 5wt%, Na 2 CO 3: 75wt%)
, And then taken out, kept in an electric furnace maintained at 900 ° C. for 150 hours, and then cooled. This test piece is cut and the microstructure of the cross section is SEM (scanning electron microscope)
And the average erosion depth that progressed along the crystal grain boundaries was determined. The results are shown in Table 4, and the high temperature intergranular corrosion resistance was evaluated.

[0034]

[Table 4]

[0035]

From the results shown in Tables 1 to 4, the large columnar cast plates 1 to 16 of the present invention have a smaller average erosion depth than the conventional columnar large cast plates 17 to 20 containing a large amount of Zr. From this, it can be seen that the columnar crystal large cast plates 1 to 16 of the present invention are excellent in high-temperature intergranular corrosion resistance. Accordingly, the columnar crystal Ni-base heat-resistant alloy large casting of the present invention has excellent high-temperature intergranular corrosion resistance.
Even if it is used under severe conditions as a stationary blade and a moving blade of a high-temperature blower, it can be used for a long period of time, and has excellent industrial effects.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Michi Matsuba 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Corporation (72) Inventor Hisataka Kawai 2-1-1 Shinhama, Araimachi, Takasago-shi, Hyogo Prefecture (72) Inventor Ikuo Okada 2-1-1, Shinaihama, Arai-machi, Takasago-shi, Hyogo Sanshi Heavy Industries, Ltd. (72) Inside Takasago Research Center, Takasago-shi, Hyogo (72) Koji Takahashi, 2-1 Shinhama, Araimachi, Takasago-shi, Hyogo Prefecture -1 In the Takasago Works, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-6-184685 (JP, A) JP-A-7-145703 (JP, A) JP-A-6-57359 (JP, A) JP Hei 9-170402 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 19/00-19/05 F01D 5/28 F02C 7/00

Claims (5)

(57) [Claims] 1. Cr in weight%: 12.0 to 14.3
%, Co: 8.5 to 11.0%, Mo: 1.0 to 3.5
%, W: 3.5 to 6.2%, Ta: 3.0 to 5.5%,
Al: 3.5 to 4.5%, Ti: 2.0 to 3.2%,
C: 0.04 to 0.12%, B: 0.005 to 0.05
%, Zr: 0.001 to 5 ppm, the balance being Ni
A columnar crystal Ni-base heat-resistant alloy large casting excellent in high-temperature intergranular corrosion resistance characterized by having a composition comprising unavoidable impurities. 2. Cr in weight%: 12.0 to 14.3.
%, Co: 8.5 to 11.0%, Mo: 1.0 to 3.5
%, W: 3.5 to 6.2%, Ta: 3.0 to 5.5%,
Al: 3.5 to 4.5%, Ti: 2.0 to 3.2%,
C: 0.04 to 0.12%, B: 0.005 to 0.05
%, Zr: 0.001 to 5 ppm, and Mg and / or Ca: 0.5 to 100 ppm
A large-sized columnar crystal Ni-base heat-resistant alloy excellent in high-temperature intergranular corrosion resistance, characterized by having a composition comprising Ni and inevitable impurities. 3. Cr in weight%: 12.0 to 14.3
%, Co: 8.5 to 11.0%, Mo: 1.0 to 3.5
%, W: 3.5 to 6.2%, Ta: 3.0 to 5.5%,
Al: 3.5 to 4.5%, Ti: 2.0 to 3.2%,
C: 0.04 to 0.12%, B: 0.005 to 0.05
%, Zr: 0.001 to 5 ppm, Pt: 0.02 to 0.5%, Rh: 0.02 to
High-temperature intergranular corrosion resistance characterized by containing one or more of 0.5% and Re: 0.02 to 0.5%, with the balance being Ni and unavoidable impurities. Excellent columnar crystal Ni-base heat-resistant alloy large casting. 4. Cr in weight%: 12.0 to 14.3
%, Co: 8.5 to 11.0%, Mo: 1.0 to 3.5
%, W: 3.5 to 6.2%, Ta: 3.0 to 5.5%,
Al: 3.5 to 4.5%, Ti: 2.0 to 3.2%,
C: 0.04 to 0.12%, B: 0.005 to 0.05
%, Zr: 0.001 to 5 ppm, and Mg and / or Ca: 0.5 to 100 ppm
Further, Pt: 0.02 to 0.5%, Rh: 0.02 to
High-temperature intergranular corrosion resistance characterized by containing one or more of 0.5% and Re: 0.02 to 0.5%, with the balance being Ni and unavoidable impurities. Excellent columnar crystal Ni-base heat-resistant alloy large casting. 5. A large turbine blade comprising a columnar crystal Ni-base heat-resistant alloy casting excellent in high temperature intergranular corrosion resistance according to claim 1, 2, 3 or 4.