JP5082112B2 - Ni-base alloy material excellent in strength, workability and creep characteristics at room temperature, and its production method - Google Patents

Description

  The present invention relates to a Ni-based alloy material excellent in strength, workability and creep characteristics at room temperature, and a method for producing the same, and in particular, uses a part produced by plastic working at room temperature for a long time at a high temperature, for example, combustion for a gas turbine. The present invention relates to a Ni-based alloy material used for container parts and the like.

  The gas turbine combustor is a component that plays a role of burning fuel to generate high-temperature and high-pressure combustion gas for driving the turbine and guiding the combustion gas to the turbine inlet. In general, the temperature of the combustion gas used in the gas turbine is 1100 ° C. to 1300 ° C., and the temperature of the combustor at this time is about 550 to 650 ° C. However, in recent years, the temperature of combustion gas has been increasing year by year in order to improve power generation efficiency, and those exceeding 1500 ° C. have been developed. In the future, it is considered that a gas turbine having a combustion gas temperature of about 1600 ° C. will be realized, and accordingly, the temperature of the combustor is expected to be about 1000 ° C. For this reason, Ni-based alloys conventionally used as combustor materials are also required to develop Ni-based alloys that exhibit creep characteristics at higher temperatures.

  Moreover, since the combustor of a gas turbine is plastically processed such as bending or drawing at normal temperature, good workability at normal temperature is also required.

  Furthermore, since the combustor of the gas turbine has a complicated shape, a thin plate is preferred for easy bending and drawing. In addition, the use of a thin plate contributes to reducing the weight of the combustor and reducing the amount of alloy used, thereby reducing the cost. Therefore, the plate used is preferably as thin as possible. However, when a combustor is manufactured using a thin plate, the strength of the combustor itself is reduced, and there is a problem that the shape is deformed when the combustor is incorporated into a gas turbine. For this reason, Ni-based alloy materials used in gas turbine combustors and the like are required to have not only excellent creep characteristics but also strength at room temperature, particularly high proof stress and tensile strength.

  In this regard, as a material of a conventional gas turbine combustor, 22% Cr-18% Fe-9% Mo-max 2.5% Co-max 1% W-max 1% Mn-max 1 described in Patent Document 1 Ni-based alloys (Hastelloy X; registered trademark) having a component composition of% Si-0.05 to 0.15% C have been used. This alloy has no problem when used in a temperature range up to about 850 ° C. as well as at about 550 to 650 ° C. However, with the recent increase in combustion gas temperature, it has become difficult for Hastelloy X to ensure sufficient creep characteristics, and the development of new heat-resistant alloys is required.

  As alloys having higher high-temperature strength than Hastelloy X, for example, Inconel (registered trademark) 718, which is a Ni-based alloy, and Inconel 617, which is also a Ni-based alloy and contains more Co, are known. However, since these materials are inferior in processability to Hastelloy X, they are forged after casting or further welded to produce a combustor, which not only restricts the shape of the combustor but also reduces the production cost. It is difficult to say that it is a practical material.

Patent Document 2 discloses a liner for a gas turbine combustor, Cr: 18 to 25 mass%, Co: 3 mass% or less, Mo + W: 7 to 12 mass%, Fe: 15 to 22 mass%, Al: 8 mass% or less, Mn 1% by mass or less, Si: 1% by mass or less, C: 0.5% by mass or less, and the balance of Y ₂ O ₃ is 0.2 to 5 mass in the parent phase of the Ni-based alloy consisting of Ni and inevitable impurities. It is proposed to use an alloy dispersed in%. This alloy has high creep characteristics by finely dispersing hard second phase Y ₂ O ₃ particles in the matrix. However, since this alloy is solidified by subjecting the uniformly dispersed powder to HIP (hot isostatic pressing), there is a problem that the manufacturing cost is increased.

  Furthermore, Patent Document 3 describes a Ni-based material having excellent room temperature workability and excellent creep characteristics when used by adding appropriate amounts of Ti, Nb, Ta, and Zr to the component composition of Hastelloy X. An alloy is proposed. However, this alloy is required to further improve creep characteristics as the combustion gas is heated. In addition, this alloy cannot be thinned due to its low strength at room temperature, leaving it difficult to bend and draw, reduce weight, and reduce costs by reducing the amount of alloy used. . Therefore, even if a thin plate is used for this purpose, it does not satisfy these requirements.

  In addition, since conventional Ni-based alloys generally prioritize quality stability, it is common to go through an ingot-making process in which the alloy is melted by a special melting method such as ESR to produce an ingot. For this reason, there are problems that productivity is low and manufacturing cost is high.

In addition, as a method of manufacturing a heat-resistant material with high productivity, for example, there is a continuous casting-hot rolling method used for manufacturing general-purpose stainless steel such as SUS304 and 316. However, the above manufacturing method is inferior in the homogeneity of the structure of the alloy material because the processing strain amount in the material manufacturing process is small compared to the conventional ingot-hot forging-hot rolling method. There is a risk of adverse effects.
US Pat. No. 2,703,277 JP-A-11-061303 JP2007-084895

  As described above, the conventional Ni-based alloy material (Hastelloy X) used in a gas turbine combustor or the like does not have sufficient creep characteristics to withstand the recent increase in operating temperature. In addition, even in Ni-based alloy materials based on the component composition of Hastelloy X, to which appropriate amounts of Ti, Nb, Ta, and Zr are added, creep that can withstand the increase in combustor temperature accompanying the recent increase in combustion gas temperature Not only has the characteristics, but also the strength at room temperature is still insufficient, so the bending workability and drawing workability obtained by using a thin plate is improved, and the combustor There was a problem that it was not possible to enjoy the advantages of weight reduction and alloy usage reduction.

  Accordingly, an object of the present invention is to provide a Ni-based alloy material that is excellent in strength and workability at room temperature, and superior in high-temperature creep characteristics over the conventional Ni-based alloy material, and the Ni-based alloy material is heated. The object is to propose a method for producing at low cost by a continuous casting method without going through an intermediate forging step.

The inventors of the present invention are based on the component composition of Hastelloy X, which is a conventional Ni-based alloy material, and a Ni-based alloy to which an appropriate amount of Ti, Nb, Ta, Zr is added without impairing workability at room temperature. In order to develop a Ni-based alloy material with excellent creep properties at higher temperatures, the composition of the composition based on Hastelloy X is Ti,
Various elements were further added to those to which Nb, Ta and Zr were added, and their effects were examined. As a result, by adding an appropriate amount of N, we have succeeded in developing a Ni-based alloy material that has excellent creep characteristics and strength at room temperature while maintaining its workability.

That is, the present invention is C: 0.03-0.30 mass%, Si: 1.5 mass% or less, Mn: 2.0 mass% or less, P: 0.05 mass% or less, S: 0.030 mass% Hereinafter, Cr: 18.0 to 28.0 mass
%, Mo: 6.0 to 15.0 mass%, Cu: 1.0 mass% or less, Co: 4.0 mass% or less, W: 3.0 mass% or less, B: 0.03 mass
% Or less, Fe: 15.0 to 25.0 mass%, N: 0.001 to 0.15
mass%, further Ti: 0.02-0.60 mass%, Nb: 0.02-0.60 mass%, Ta: 0.02-0.6 mass% and Zr: 0.02-0.60 mass% At least one selected from the group consisting of (Ti + Nb + Ta + Zr): 0.02 to 0.60 mass%, with the balance being Ni and inevitable impurities, A Ni-based alloy material excellent in workability and creep characteristics is proposed.

In the Ni-based alloy material according to the present invention,
(1) The N content is 0.005 to 0.15 mass%,
(2) The N content is 0.010 to 0.10 mass%,
(3) containing at least one of carbides and nitrides having a maximum particle size of 10 μm or less, or charcoal / nitrides obtained by combining these,
(4) The area ratio of the carbides and nitrides precipitated in the crystal grains, or the carbon / nitride formed by combining these is 0.5% to 20%,
(5) The carbide is M ₆ C type, M ₂₃ C ₆ type, and the nitride is MN type.
Is a more preferable solution.

In the present invention, C: 0.03 to 0.30 mass%, Si: 1.5 mass% or less, Mn: 2.0 mass% or less, P: 0.05 mass% or less, S: 0.030 mass
%, Cr: 18.0 to 28.0 mass%, Mo: 6.0 to 15.0 mass
%, Cu: 1.0 mass% or less, Co: 4.0 mass% or less, W: 3.0 mass% or less, B: 0.03 mass
%: Fe: 15.0-25.0 mass%, N: 0.001-0.15 mass%, Ti: 0.02-0.60 mass%, Nb: 0.02-0.60 mass
%, Ta: 0.02 to 0.6 mass% and Zr: 0.02 to 0.60 mass%, (Ti + Nb + Ta + Zr): 0.02 to 0.60 mass The Ni-based alloy containing Ni and the balance of Ni and inevitable impurities is continuously cast into a continuous cast slab, and then the continuous cast slab is hot-rolled and finish-annealed. We propose a method for producing a Ni-based alloy material that is excellent in strength, workability, and creep characteristics at room temperature.

In the method for producing a Ni-based alloy material according to the present invention,
(1) The N content is 0.005 to 0.15 mass%,
(2) The N content is 0.010 to 0.10 mass%,
(3) Hot rolling, intermediate annealing, cold rolling, and then finish annealing the continuous cast slab,
(4) After the finish annealing, the aging heat treatment is further performed at a temperature of 800 to 1000 ° C. for 16 hours or more, so that carbide, nitride, or carbon / nitride formed by combining these in the crystal grains Depositing at a rate of 0.5% to 20%,
Is a more preferable solution.

(1) According to the present invention, a Ni-based alloy material that is superior in creep characteristics at higher temperatures, strength at normal temperature, and workability compared to conventional Ni-based alloys can be obtained. A material corresponding to high temperature can be provided. Accordingly, it is possible to provide a Ni-based alloy material that can withstand the increase in combustor temperature accompanying the recent increase in combustion gas temperature.
(2) Also, according to the present invention, the workability at room temperature is equivalent to that of the conventional alloy, but the strength at room temperature is excellent, so the thickness of the combustor material can be reduced, and the combustor processing This contributes to reducing the weight of the combustor.
(3) According to the present invention, since it is possible to manufacture by a continuous casting method suitable for mass production, it is compared with a conventional alloy manufactured by a special melting-ingot-hot forging-hot rolling process. Thus, the manufacturing cost can be significantly reduced.

  Based on the component composition of Hastelloy X, the inventors have added an appropriate amount of Ti, Nb, Ta, or Zr to a Ni-based alloy material, and further added an appropriate amount of N positively. The inventors have found that the creep characteristics at higher temperatures and the strength at room temperature are improved while maintaining the required processability, and the present invention has been completed. In the following, experiments that triggered the development of the present invention will be described first.

  The inventors first experimented on the influence of N addition on the strength of a Ni-based alloy material at room temperature. In this experiment, C: 0.06 mass%, Cr: 21.5 mass%, Mo: 9.0 mass%, Co: 1.2 mass%, W: 0.6 mass%, Fe: 19.0 mass%, B: 0.00. Ni-based alloy containing 003 mass%, Nb: 0.2 mass%, Ti :: 0.1 mass%, the balance being substantially made of Ni, and further adding N in the range of 0 to 0.20 mass% Was melted. The molten material is continuously cast to form a continuous cast slab. The continuous cast slab is reheated to 1200 ° C. and then hot-rolled in a temperature range of 900 to 1200 ° C. to obtain a hot-rolled sheet having a thickness of 6 mm. . The hot-rolled sheet was subjected to intermediate annealing in the temperature range of 1100 ° C. to 1300 ° C. for 1 to 60 minutes, and then cold-rolled to obtain a cold-rolled sheet having a thickness of 1.5 mm. Thereafter, finish annealing was performed under conditions of 1100 to 1300 ° C. × 1 to 60 minutes to obtain a cold-rolled annealed plate.

  The Ni-based alloy plate thus obtained was subjected to a tensile test at room temperature in accordance with JIS Z2241, and the influence of N on 0.2% proof stress, tensile strength and elongation value was examined. FIGS. 1A to 1C show the results of the tensile test. From this result, it can be seen that the 0.2% proof stress (a) and the tensile strength (b) increase as the N content increases. On the other hand, since the elongation value (c) decreases as the N content increases, it was also found that excessive addition of N deteriorates workability. These effects were remarkable in the range where the N content was small.

  Next, the inventors experimented on the effect of N addition on the creep characteristics. In this experiment, C: 0.06 mass%, Cr: 21.5 mass%, Mo: 9.0 mass%, Co: 1.2 mass%, W: 0.6 mass%, Fe: 19.0 mass%, Nb: 0.00. 2% by mass, Ti: 0.1% by mass, with the balance being substantially Ni, a Ni-based alloy with 0.03 mass% added N is melted and continuously cast to continuously cast slabs The continuous cast slab is hot-rolled under the same conditions as described above, intermediate-annealed, cold-rolled, and then finish-annealed at a temperature of 1150 ° C. to obtain a Ni-based alloy material having a plate thickness of 1.5 mm did. This Ni-based alloy material was subjected to a creep test under the conditions of 850 ° C. and 110 MPa in accordance with ASTM E139, and the effect of N addition on the creep rupture time was examined. FIG. 2 shows the result of the creep test. From this result, it was confirmed that addition of N to the Ni-based alloy material improves the creep characteristics.

  Next, the inventors simulated a use at a high temperature for 16 hours at 850 ° C. for a Ni-based alloy plate obtained by processing a Ni-based alloy having the same composition as described above in the same manner as described above. An aging heat treatment was performed, and the cross section was observed by SEM, and the distribution of carbides and nitrides, and carbon / nitrides obtained by combining them was investigated.

3 (a) and 3 (b) show the contents of carbides, nitrides, and the like of a Ni-based alloy (a) to which N is not added and a Ni-based alloy (b) to which 0.03 mass% of N is added. It is the SEM photograph. This observation was performed with a scanning electron microscope (SEM) after etching with a curling reagent (50 ml of methanol, 50 ml of hydrochloric acid, 2.5 g of cupric chloride). In addition, by the analysis by EPMA, what is observed in white in the SEM image is observed as M ₆ C type (Mo, W) ₆ C carbide or M ₂₃ C ₆ type Cr ₂₃ C ₆ carbide or black. It was found to be MN type (Ti, Nb) N nitride. In addition, another investigation revealed that coarse carbides and nitrides of about several μm were insoluble solid carbides and nitrides before aging heat treatment at 850 ° C. for 16 hours, that is, in the final annealing stage.

  From the photograph shown in FIG. 3, in the Ni-based alloy material with no N added, carbides are mainly present at the grain boundaries, and very few are present in the crystal grains. On the other hand, in the Ni-based alloy material to which 0.03 mass% of N is added, carbides are precipitated at the crystal grain boundaries as in the case of the N-free material, but fine precipitates are also present in the crystal grains. It was found that the substances were uniformly deposited and distributed.

In addition, in the Ni-based alloy material to which N is added by 0.03 mass%, N that was dissolved in the matrix during the heat treatment (aging treatment) at 850 ° C. for 16 hours is extremely fine in the crystal grains. It is considered that M ₆ C type carbides are precipitated in the crystal grains using the very fine MN type nitrides as nuclei. Therefore, as shown in FIG. 3, the Ni-based alloy material to which N is added has fine carbides with nitrides as nuclei in the crystal grains, so that the movement of dislocations is prevented during the creep test. It is estimated that the creep characteristics were improved. The present invention has been developed based on the above novel findings.

The reason why the component composition of the Ni-based alloy of the present invention is defined in the above range will be described below.
C: 0.03-0.30 mass%
C forms a carbide of M ₆ C type. In addition, it is an element that forms new M ₆ C type carbides or M ₂₃ C ₆ type carbides during use at high temperatures and strengthens the crystal grain boundaries and crystal grains to improve the creep characteristics. In order to obtain the effect, it is necessary to add at least 0.03 mass%. However, if added in excess of 0.30 mass%, coarse undissolved carbides are formed and remain to deteriorate the workability and creep characteristics. Therefore, C is set to a range of 0.03 to 0.30 mass%. Preferably it is 0.03-0.15 mass%, More preferably, it is set as the range of 0.03-0.10 mass%.

Si: 1.5 mass% or less Si is an element necessary for deoxidation and is an element effective for improving oxidation resistance. However, if added over 1.5 mass%, cracks occur during continuous casting, or the weldability of the material is reduced. Therefore, Si is 1.5 mass% or less.

Mn: 2.0 mass% or less Mn is an element necessary for deoxidation as well as Si, and is also an element effective for desulfurization. However, if added over 2.0 mass%, the oxidation resistance is deteriorated, so the upper limit is made 2.0 mass%.

P: 0.5 mass% or less P is contained due to scrap components as raw materials, and is an element that is difficult to remove completely by refining. P is an element that deteriorates hot workability. In particular, when the content exceeds 0.05 mass%, the influence becomes significant, so the upper limit is set to 0.05 mass%.

S: 0.030 mass% or less S is an element contained due to a scrap component as a raw material. If the content exceeds 0.030 mass%, the hot workability deteriorates and the yield is lowered, so the upper limit is made 0.030 mass%. Preferably, it is 0.010 mass% or less.

Cr: 18.0 to 28.0 mass%
Cr is one of the main elements constituting the Ni-based alloy material of the present invention. A good protective film is formed on the Cr component to improve the oxidation resistance of the alloy. Further, during use at a high temperature, M ₂₃ C ₆ type carbides are formed, and the strength of the grain boundaries is increased. If the content is less than 18.0 mass%, desired oxidation resistance cannot be ensured. On the other hand, when the content exceeds 28.0 mass%, a harmful phase such as σ phase is precipitated, and the oxidation resistance and workability are also lowered. Therefore, the Cr content is in the range of 18.0 to 28.0 mass%. Preferably, it is in the range of 20.0 to 24.0.

Mo: 6.0 to 15.0 mass%
Mo is one of the main elements constituting the Ni-based alloy material of the present invention. It has the effect of improving the creep characteristics by solid solution in the matrix, and strengthens by forming C and M ₆ C type carbides. Further, during use at high temperatures, M ₆ C type carbides are formed and precipitated in the crystal grains, thereby improving the creep characteristics. When the content is less than 6.0 mass%, sufficient creep characteristics cannot be obtained. On the other hand, if the Mo content exceeds 15.0 mass%, the oxidation resistance deteriorates. Therefore, the Mo content is in the range of 6.0 to 15.0 mass%. Preferably it is the range of 8.0-12.0 mass%.

Cu: 1.0 mass% or less Cu is an element contained due to scrap as a raw material, and if it exceeds 1.0 mass%, the oxidation resistance decreases. Therefore, the Cu content is set to 1.0 mass% or less.

Co: 4.0 mass% or less Co is an element that improves the creep characteristics by a solid solution strengthening action. However, Co is an expensive element, and the above effect is saturated when it exceeds 4 mass%, and an effect sufficient for the amount added cannot be obtained. Therefore, the upper limit of the amount of Co added is 4.0 mass%.

W: 3.0 mass% or less W is an element that improves creep characteristics by a solid solution strengthening action. Further, C and M ₆ C type carbides are formed and strengthened. Further, even during use at high temperatures, M ₆ C type carbides are formed and precipitated in the crystal grains, thereby improving the creep characteristics. However, W is an expensive element, and the above effect is saturated when it exceeds 3.0 mass%, and an effect corresponding to the amount added cannot be obtained. Therefore, the upper limit of the addition amount of W is set to 3.0 mass%.

B: 0.03 mass% or less B is an element that increases the strength of crystal grain boundaries and improves creep characteristics. However, when B is added in an amount exceeding 0.03 mass%, a compound having a low melting point is precipitated and the hot workability is lowered. Therefore, the upper limit of the B addition amount is 0.03 mass%.

Fe: 15.0-25.0 mass%
Fe is an element contained due to scrap as a raw material. When the content exceeds 25.0 mass%, the oxidation resistance decreases. On the other hand, when the content is reduced to less than 15.0 mass%, the content of Ni is relatively increased, so that not only the raw material cost is increased but also the hot workability is decreased. Therefore, the content of Fe is set to 15.0 to 25.0 mass%. Preferably it is the range of 16.0-20.0 mass%.

N: 0.001 to 0.15 mass%
In the Ni-base alloy, N has been conventionally considered as an element to be suppressed as an impurity during vacuum melting. On the other hand, in the present invention, this N has an effect of increasing the strength at room temperature or high temperature by dissolving in the matrix, and is considered to be a useful element that should be positively added. Moreover, Ti, Nb, Ta, and Zr form MN-type nitrides, suppress the growth of crystal grains during annealing, and make the crystal grains finer, resulting in an improvement in strength at room temperature. Furthermore, during use at a high temperature, an extremely fine MN type nitride is precipitated in the crystal grains, and this serves as a nucleus to precipitate the M ₆ C type carbide uniformly and finely, thereby improving the creep characteristics. is there. Such an effect is manifested by addition of 0.001 mass% or more. However, if N is added in an amount exceeding 0.15 mass%, the workability at room temperature is deteriorated due to hardening of the parent phase or coarsening of the nitride. Therefore, in the present invention, this N is added in the range of 0.001 to 0.15 mass%. Preferably it is 0.005-0.15 mass%, More preferably, it is 0.010-0.10 mass%.

One selected from Ti: 0.02 to 0.60 mass%, Nb: 0.02 to 0.60 mass%, Ta: 0.02 to 0.60 mass%, and Zr: 0.02 to 0.60 mass% Or two or more types of Ti, Nb, Ta, and Zr form MN-type nitride that remains even after annealing, suppresses the growth of crystal grains during annealing, and strength at room temperature by making the crystal grains finer To improve. In addition, during use at a high temperature, very fine MN-type nitride is precipitated in the crystal grains, and M ₆ C-type carbide is precipitated uniformly and finely using the MN-type nitride as a nucleus, thereby improving the creep characteristics. Furthermore, in the process of producing a Ni based alloy material, and suppress the coarse M _{6 C} type carbide and solid solution carbide of M 6 _C-type precipitates, improves the processability and creep properties. In addition, the formation of row-like M ₆ C-type carbides that continuously precipitate is also suppressed. The effect is manifested by adding 0.02 mass% or more. However, if these elements are added excessively in excess of 0.60 mass%, the carbides precipitated in the alloy are coarsened and hot workability and creep characteristics are deteriorated. Therefore, in the present invention, the above elements are added in the range of 0.02 to 0.60 mass%. Preferably, it is the range of 0.05-0.20 mass%.

(Ti + Nb + Ta + Zr): 0.02 to 0.60 mass%
The above effect is the same for all elements, and the same effect can be obtained by adding one or more elements. Moreover, the characteristic deterioration of excessive addition is also the same. Therefore, the total addition amount of these elements also needs to be in the range of 0.02 to 0.60 mass%. Preferably it is 0.05-0.20 mass%.

  In the Ni-based alloy of the present invention, elements other than the above components are Ni and inevitable impurities. However, as long as the effects of the present invention are not impaired, addition of other elements beyond the range of impurities does not affect the present invention.

Next, carbides and nitrides precipitated in the Ni-based alloy material according to the present invention or carbon / nitrides obtained by combining these will be described.
The Ni-based alloy material of the present invention is obtained by subjecting a continuously cast slab to hot rolling and then heat treatment or further cold rolling and heat treatment to obtain M ₆ C type carbide, M ₂₃ C ₆ type carbide, and MN type. Nitride, or a composite of these, is dissolved in the matrix as much as possible, and carbide and nitride are uniformly and finely precipitated in the grain boundaries and grains during use at high temperatures. is there.

  However, the carbides and nitrides in the Ni-base alloy material or the carbon / nitride mentioned above are not only the carbides and nitrides that precipitate during use at high temperatures, but also the process of producing a Ni-base heat-resistant alloy (mainly in continuous casting). There are also row-like carbides that are deposited in a row at the time of solidification), coarse MN-type nitrides, and carbon / nitrides in which these are combined. If these carbides, nitrides, etc. are divided in the subsequent rolling process and melt or are reduced in size or amount by finish annealing, the workability at normal temperature will not be adversely affected. However, when the above carbides, nitrides, etc. are not completely dissolved and remain coarse, and the particle size is 10 μm or more, the carbides or nitrides, or the carbons / nitrides and the mother during processing at room temperature. Cracks may occur from the interface with the phase, which may degrade workability. Therefore, it is preferable that these particle sizes precipitated in the Ni-based alloy be 10 μm or less. More preferably, it is 5 μm or less. The particle size of carbides and nitrides can be controlled by controlling the contents of C, N, Ti, Nb, Ta, and Zr, adjusting the temperature and time of the above-described finish annealing, and the like.

In addition, the amount of M ₆ C-type carbide that precipitates uniformly and finely in crystal grains during use at a high temperature can also be controlled by changing the amount of N added. In this regard, when N is not added, as is apparent from the photograph of FIG. 3, very little M ₆ C type carbide precipitates in the crystal grains. On the other hand, when N is added, it can be seen that the amount of carbide precipitated in the crystal grains increases. The fine carbides precipitated in the crystal hinder the movement of dislocations during the creep test, making it difficult for creep deformation and improving the creep characteristics. However, if this carbide is precipitated too much, the ductility of the material is deteriorated and the creep characteristics are deteriorated. Therefore, it is desirable that the area ratio of carbides in crystal grains precipitated during use at a high temperature is about 0.5 to 20%. More preferably, it is 1 to 15%.

Next, the manufacturing method of the Ni-based alloy material of the present invention will be described.
The Ni-based alloy material of the present invention is obtained by melting an alloy having the above-described component composition by a known method to form a continuous cast slab using a continuous casting method, and then hot rolling the continuous cast slab to form a plate. Or after making it strip | belt shape, it manufactures by carrying out intermediate annealing, cold rolling, and finishing annealing further.

  In the above manufacturing method, the finish annealing performed after hot rolling or after cold rolling is a solution of carbide and nitride forming elements, and carbide or nitride, or a composite of carbide and nitride (carbon / nitride). It is preferable to perform heat treatment so that the product is dissolved in the matrix as much as possible. This heat treatment is preferably performed using a box annealing furnace or a continuous annealing furnace in a temperature range of 1100 to 1300 ° C. for an appropriate time (about 1 to 60 minutes) depending on the thickness of each plate. It is preferable to be in the range. The Ni-based alloy material of the present invention is excellent in dissolving the carbide or nitride precipitated in the manufacturing process or a composite of carbide and nitride in the alloy as much as possible by this solution heat treatment, and reducing them as much as possible. In addition to imparting high workability, the carbide and nitride are reprecipitated uniformly and finely in the crystal grains during subsequent use at high temperatures, so that excellent creep characteristics are exhibited.

  The operating temperature range of the Ni-based alloy of the present invention is preferably less than 1100 ° C. This is because carbides precipitated in the crystal grains are dissolved at a temperature of 1100 ° C. or higher, and sufficient high-temperature strength cannot be obtained. The Ni-based alloy of the present invention is characterized by exhibiting excellent high-temperature strength at temperatures exceeding 800 ° C., but even when used at temperatures below 800 ° C., high-temperature strength higher than that of conventional Hastelloy X is obtained. Of course.

In this example, using an electric furnace, the alloys of Alloy Nos. 1 to 17 having the composition shown in Table 1 were melted in an air atmosphere, and then cast by a continuous casting machine. 150 mmt × 1000 mmW × A continuous cast slab of 6000 ml was obtained. The obtained continuous cast slab is heated to 1200 ° C. and hot-rolled in a temperature range of 900 to 1200 ° C. to form a hot-rolled coil having a thickness of 6 mm, and then subjected to intermediate annealing (1150 ° C.) and pickling. An example will be described in which cold rolling is performed to obtain a cold-rolled material having a thickness of 1.5 mm, followed by finish annealing at a temperature of 1150 ° C. to obtain a cold-rolled annealed plate.
Then, the obtained cold-rolled annealed plate was subjected to the following tensile test, creep test, and carbide and nitride particle size measurement. The cold-rolled annealed plate was subjected to an aging heat treatment at 850 ° C. for 16 hours, and then subjected to measurement of the area ratio of carbides or nitrides within the crystal grains, or charcoal / nitrides. Tables 1 and 2 show the component compositions of the alloys used.

Contents of Various Tests (1) Creep Test The creep test was performed under the two conditions a and b shown in Table 3 in accordance with ASTM E139, and the time to break was measured.

(2) Particle size measurement of carbide or nitride, or charcoal / nitride The particle size of carbide and nitride is obtained by etching a cross-section of the alloy material after cold rolling and finish annealing with a curling reagent by SEM. Observed, three or more secondary electron images were taken to determine the particle size of each carbide, nitride, or nitrogen / carbide, and the largest particle size among them was taken as the maximum particle size regardless of the type.

(3) Carbide and nitride area ratio in the crystal grains after aging at 850 ° C. for 16 hours After finishing annealing, the cross section of the material subjected to heat treatment at 850 ° C. for 16 hours is further etched with a curling reagent, This was photographed with an SEM, and the area ratio of carbide, nitride, or charcoal / nitride precipitated in the crystal grains was measured by image analysis.

  The results of the above tests are shown in Tables 4 and 5. From the results shown in Tables 4 and 5, alloys (alloys 1 to 9) having a composition suitable for the present invention have a strength at room temperature represented by 0.2% proof stress and tensile strength, and have a Hastelloy X equivalent. It was found to be higher than (Alloy 17) and Ni-based alloys (Comparative Alloys 11 and 12) in which appropriate amounts of Ti, Nb, Ta, and Zr were added thereto based on the component composition of Hastelloy X. It was also found that the invention alloy was better than the reference alloy 17 and the comparative alloys 11 and 12 in the creep characteristics. Furthermore, in terms of workability, the invention alloy was equivalent to the reference alloy 17 and the comparative alloys 11 and 12.

  On the other hand, the comparative alloys (Nos. 14 and 15) in which N is added to the component composition beyond the range defined by the present invention have higher strength than the conventional alloys, but the elongation value is low and the workability is remarkably inferior. I found out. Moreover, the creep rupture time was also inferior compared with invention alloy. Furthermore, it was found that the creep characteristics were inferior in the alloy having a low C content (Comparative Alloy 13) and the alloy not added with Ti, Nb, Ta, and Zr (Comparative Alloy 16). From the above results, it was found that the alloy of the present invention is excellent.

  The present invention is useful as a combustor for a gas turbine because it can provide a Ni-based alloy material that has excellent strength and workability at room temperature and excellent creep characteristics during use at high temperatures. In addition to this, it can be used as a material in a field such as a combustion part of an industrial furnace or an exhaust treatment device, which is processed into a complicated shape and then used in a high temperature atmosphere.

It is a graph which shows the influence of N content which acts on 0.2% yield strength, tensile strength, and an elongation value. It is a graph which shows the comparison of the creep rupture time on condition of 850 degreeC and 110 Mpa by N: 0.03mass% addition presence or absence. N: It is the SEM image which showed the precipitation condition of the precipitate of the Ni base alloy after heat processing for 16 hours at 850 degreeC by the presence or absence of 0.03 mass% addition.

Claims (11)

C: 0.03 to 0.30 mass%, Si: 1.5 mass% or less, Mn: 2.0 mass% or less, P: 0.05 mass% or less, S: 0.030 mass% or less, Cr: 18. 0 to 28.0 mass
%, Mo: 6.0 to 15.0 mass%, Cu: 1.0 mass% or less, Co: 4.0 mass% or less, W: 3.0 mass% or less, B: 0.03 mass
% Or less, Fe: 15.0 to 25.0 mass%, N: 0.001 to 0.15
mass%, further Ti: 0.02-0.60 mass%, Nb: 0.02-0.60 mass%, Ta: 0.02-0.6 mass% and Zr: 0.02-0.60 mass% At least one selected from the group consisting of (Ti + Nb + Ta + Zr): 0.02 to 0.60 mass%, with the balance being Ni and inevitable impurities, Ni-based alloy material with excellent workability and creep characteristics. The Ni-based alloy material having excellent strength, workability, and creep characteristics at room temperature according to claim 1, wherein the N content is 0.005 to 0.15 mass%. The Ni-based alloy material having excellent strength, workability, and creep characteristics at room temperature according to claim 1, wherein the N content is 0.010 to 0.10 mass%. 4. The material according to claim 1, comprising at least one of carbides and nitrides having a maximum particle size of 10 μm or less, or charcoal / nitrides obtained by combining them. 5. Ni-based alloy material. The area ratio of carbides, nitrides precipitated in the crystal grains, or carbon / nitrides formed by combining these is 0.5% to 20%, wherein any one of claims 1 to 4 The Ni-based alloy material described in 1. The Ni-based alloy material according to any one of claims 1 to 5, wherein the carbides are M ₆ C type and M ₂₃ C ₆ type, and the nitrides are MN type. C: 0.03-0.30 mass%, Si: 1.5 mass% or less, Mn: 2.0 mass% or less, P: 0.05 mass% or less, S: 0.030 mass
%, Cr: 18.0 to 28.0 mass%, Mo: 6.0 to 15.0 mass
%, Cu: 1.0 mass% or less, Co: 4.0 mass% or less, W: 3.0 mass% or less, B: 0.03 mass
%: Fe: 15.0-25.0 mass%, N: 0.001-0.15 mass%, Ti: 0.02-0.60 mass%, Nb: 0.02-0.60 mass
%, Ta: 0.02 to 0.6 mass% and Zr: 0.02 to 0.60 mass%, (Ti + Nb + Ta + Zr): 0.02 to 0.60 mass The Ni-based alloy containing Ni and the balance of Ni and inevitable impurities is continuously cast into a continuous cast slab, and then the continuous cast slab is hot-rolled and finish-annealed. A method for producing a Ni-based alloy material that is excellent in strength, workability, and creep properties at room temperature. The method for producing a Ni-based alloy material having excellent strength, workability and creep characteristics at room temperature according to claim 7, wherein the N content is 0.005 to 0.15 mass%. The method for producing a Ni-based alloy material having excellent strength, workability, and creep characteristics at room temperature according to claim 7, wherein the N content is 0.010 to 0.10 mass%. The method for producing a Ni-base alloy material according to any one of claims 7 to 9, wherein the continuous cast slab is hot-rolled, intermediate-annealed, cold-rolled, and then finish-annealed. After the finish annealing, an aging heat treatment is further performed at a temperature of 800 to 1000 ° C. for 16 hours or more, so that carbides, nitrides, or carbons / nitrides formed by combining these in the crystal grains are 0 in area ratio. The method for producing a Ni-based alloy material according to any one of claims 7 to 10, wherein the precipitation is performed by 5% to 20%.

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