WO2020195049A1 - Method for producing ni-based super-heat-resistant alloy, and ni-based super-heat-resistant alloy - Google Patents

Method for producing ni-based super-heat-resistant alloy, and ni-based super-heat-resistant alloy Download PDF

Info

Publication number
WO2020195049A1
WO2020195049A1 PCT/JP2020/001725 JP2020001725W WO2020195049A1 WO 2020195049 A1 WO2020195049 A1 WO 2020195049A1 JP 2020001725 W JP2020001725 W JP 2020001725W WO 2020195049 A1 WO2020195049 A1 WO 2020195049A1
Authority
WO
WIPO (PCT)
Prior art keywords
resistant alloy
heat
less
heat treatment
plastic working
Prior art date
Application number
PCT/JP2020/001725
Other languages
French (fr)
Japanese (ja)
Inventor
悠輔 巽
韓　剛
Original Assignee
日立金属株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日立金属株式会社 filed Critical 日立金属株式会社
Priority to JP2020520084A priority Critical patent/JP6826766B1/en
Publication of WO2020195049A1 publication Critical patent/WO2020195049A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/10—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of nickel or cobalt or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working

Definitions

  • the present invention relates to a method for producing a Ni-based superheat-resistant alloy and, specifically, a Ni-based superheated alloy having a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more. It relates to a method for producing a heat-resistant alloy and a Ni-based super heat-resistant alloy.
  • Ni-based super heat-resistant alloys such as Inconel (registered trademark) 718 alloy are often used.
  • heat-resistant parts having a high heat-resistant temperature are required.
  • the gamma prime (hereinafter, also referred to as “ ⁇ '”) phase which is a precipitation strengthening phase of an intermetallic compound having Ni 3 Al as a main composition. It is most effective to increase the amount of.
  • the Ni-based superheat-resistant alloy further contains the ⁇ 'forming elements Al, Ti, and Nb, so that the high-temperature strength of the Ni-based superheat-resistant alloy can be further improved.
  • a Ni-based super heat resistant alloy having a larger amount of ⁇ 'phase will be required.
  • Ni-based superheat-resistant alloys are difficult to process because the deformation resistance of hot processing increases as the ⁇ 'phase increases.
  • the amount of the ⁇ 'phase is 35 to 40 mol% or more, the processability is particularly lowered.
  • alloys such as Inconel (registered trademark) 713C alloy, IN939, IN100, and Mar-M247 have a particularly large number of ⁇ 'phases, which makes plastic working impossible, and are usually cast as cast alloys (as-cast). Used in.
  • Patent Document 1 As a proposal for improving the hot plastic workability of such a Ni-based superheat-resistant alloy, in Patent Document 1, a Ni-based superheat-resistant alloy ingot having a composition having a ⁇ 'molar ratio of 40 mol% or more is processed at a processing rate of 5%. A manufacturing method is described in which cold working is performed at a temperature of less than 30% and then heat treatment is performed at a temperature exceeding the ⁇ 'solid solution temperature. In this method, a recrystallization rate of 90% or more, which enables hot working to be applied to a Ni-based superheat-resistant alloy, is obtained by combining a cold working step and a heat treatment step.
  • Ni-based superheat-resistant alloy having a large amount of ⁇ 'phase
  • a fine wire of Ni-based super heat-resistant alloy is required as a modeling material in that case.
  • This thin wire can also be used by processing it into a component shape such as a spring.
  • the wire diameter (diameter) of the thin wire of the Ni-based superheat-resistant alloy is, for example, as thin as 5 mm or less and further 3 mm or less.
  • a thin wire for example, it is efficient to prepare a "wire rod" having a wire diameter of 10 mm or less as an intermediate product and perform plastic working on the wire rod to produce it. If this intermediate product, "wire rod", can also be obtained by plastic working, fine wires of Ni-based superheat-resistant alloy can be efficiently produced.
  • a method for producing such a fine wire of a super heat-resistant alloy a method has been proposed in which a cast wire having a wire diameter of 5 mm or more is used as a starting material, a bundle of these cast wires is hot-extruded, and then separated. Patent Document 2).
  • Patent Document 1 is effective for Ni-based superheat-resistant alloys to which hot working is applied.
  • the method of Patent Document 2 is effective for producing fine wires in a limited component composition, but can be applied only to the component composition, and the amount of ⁇ 'phase is "35 mol% or more" described later.
  • the method of Patent Document 2 has a problem that the process is complicated and the manufacturing cost is high.
  • in producing thin wires and wire rods there is a problem that if cracks occur in the middle of the process, the processing rate is limited and plastic working cannot be performed to a predetermined wire diameter.
  • a method for producing a Ni-based superheat resistant alloy This method (A) A temperature of 900 ° C. or higher with respect to a material having a carbon content of 0.05 to 0.25% by mass and a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more.
  • the process of producing the first processed material by cooling after performing plastic working in (B) It includes a step of heating the first processed material to a temperature of 900 ° C. or higher to perform heat treatment to prepare the first heat-treated material.
  • the first heat-treated material includes a step of plastically working at a temperature of 500 ° C. or lower to produce a second processed material.
  • the second processed material further includes a step of performing a heat treatment at a temperature of 900 ° C. or higher.
  • the Ni-based superheat-resistant alloy is in mass%.
  • C 0.05-0.25%, Cr: 8.0-25.0%, Al: 0.5-8.0%, Ti: 0.4-7.0%, Co: 0-28.0%, Mo: 0-8.0%, W: 0 to 15.0%, Nb: 0-4.0%, Ta: 0-5.0%, Fe: 0 to 10.0%, V: 0-1.2%, Hf: 0-3.0%, B: 0 to 0.300%, Zr: 0 to 0.300% It is preferable that the balance is composed of Ni and impurities.
  • a Ni-based superheat resistant alloy is provided.
  • This alloy is for cold plastic working and It has a component composition having a carbon content of 0.05 to 0.25% by mass and an equilibrium precipitation amount of the gamma prime phase at 700 ° C. of 35 mol% or more.
  • the area ratio of M 23 C 6 is 4.0 area% or less, and the average particle size of the maximum diameter of the crystal grains is 1.4 to 100 ⁇ m.
  • the hardness of the Ni-based superheat-resistant alloy is preferably 460 HV or less.
  • the Ni-based superheat-resistant alloy is in mass%.
  • C 0.05-0.25%, Cr: 8.0-25.0%, Al: 0.5-8.0%, Ti: 0.4-7.0%, Co: 0-28.0%, Mo: 0-8.0%, W: 0 to 15.0%, Nb: 0-4.0%, Ta: 0-5.0%, Fe: 0 to 10.0%, V: 0-1.2%, Hf: 0-3.0%, B: 0 to 0.300%, Zr: 0 to 0.300% It is preferable that the balance is composed of Ni and impurities.
  • the cross-sectional microstructure of the material 3 (heat treatment temperature 1050 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image.
  • the cross-sectional microstructure of the material 4 (heat treatment temperature 1100 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image.
  • Cross-sectional microstructure of material 5 (heat treatment temperature 1150 ° C.) in Example 1, EPMA mapping diagram of Cr and Nb, and EBSD image.
  • the cross-sectional microstructure of the material 6 (heat treatment temperature 1200 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image.
  • FIG. 7 is a diagram showing the relationship between the heat treatment temperature and the number density of carbides when the first heat-treated material (material) is produced by heat-treating the first processed material in Example 1.
  • the present invention provides a new method capable of producing a Ni-based superheat-resistant alloy having excellent plastic workability and a Ni-based superheat-resistant alloy by a new approach different from the conventional hot plastic working.
  • the present inventor has studied the plastic workability of a Ni-based superheat resistant alloy having a large amount of ⁇ 'phase. As a result, it was found that it is possible to perform cold plastic working on a Ni-based superheat-resistant alloy that has been heat-treated by heating again after hot plastic working. At that time, it was found that nanocrystal grains were generated in the structure of the Ni-based superheat-resistant alloy by cold plastic working at a processing rate of 30% or more. It is presumed that the formation of these nanocrystal grains contributes to the dramatic improvement in the plastic workability of the Ni-based superheat-resistant alloy.
  • the method for producing a Ni-based superheat resistant alloy having a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more is (A) A temperature of 900 ° C. or higher with respect to a material having a carbon content of 0.05 to 0.25 mass% and a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more.
  • the process of producing the first processed material by cooling after performing plastic processing in (B) It includes a step of heating the first processed material to a temperature of 900 ° C. or higher to perform heat treatment to prepare the first heat-treated material.
  • the first heat-treated material is used as a material, and this material is subjected to plastic working at a temperature of 500 ° C. or lower to produce a second processed material.
  • the Ni-based superheat-resistant alloy targeted by the present invention is a component having a carbon content of 0.05 to 0.25% by mass and an equilibrium precipitation amount of the gamma prime ( ⁇ ') phase at 700 ° C. of 35 mol% or more.
  • ⁇ ' the amount of the ⁇ 'phase of the Ni-based superheat resistant alloy can be expressed by a numerical index such as "volume fraction" or "area ratio" of the ⁇ 'phase.
  • the amount of the ⁇ 'phase is represented by a numerical index of “ ⁇ 'molar rate”.
  • the ⁇ 'molar ratio is a stable equilibrium precipitation amount of the gamma prime phase in which a Ni-based superheat resistant alloy can be precipitated in a thermodynamic equilibrium state.
  • the value of the equilibrium precipitation amount of the gamma prime phase expressed in "molar ratio" is determined by the component composition of the Ni-based superheat resistant alloy.
  • the value of mol% of this equilibrium precipitation amount can be obtained by analysis by thermodynamic equilibrium calculation. In the analysis by thermodynamic equilibrium calculation, it can be obtained accurately and easily by using various thermodynamic equilibrium calculation software.
  • the ⁇ 'molar ratio of the Ni-based superheat-resistant alloy is defined as the “equilibrium precipitation amount at 700 ° C.”.
  • the high temperature strength of the Ni-based superheat resistant alloy can be evaluated by the equilibrium precipitation amount of the gamma prime phase in the structure, and the larger the high temperature strength, the more difficult the hot plastic working.
  • the equilibrium precipitation amount of the gamma prime phase in the structure is generally about 700 ° C. or lower, the temperature dependence becomes small and becomes almost constant, so the value at "700 ° C.” is used as a reference.
  • the ⁇ 'molar ratio of the Ni-based superheat resistant alloy is larger.
  • increasing the ⁇ 'molar ratio greatly contributes to the improvement of the cold plastic workability of the Ni-based superheat resistant alloy.
  • nanocrystal grains are most likely to be generated from the phase interface between the austenite phase (gamma ( ⁇ ) phase), which is a matrix of Ni-based superheat-resistant alloys, and the gamma prime phase.
  • FIG. 1 shows an example of an EBSD image of a cross-sectional microstructure produced by cold plastic working of a wire rod in the manufacturing method of the present invention.
  • the EBSD measurement conditions are as follows: Using the EBSD measurement system "OIM Version 5.3.1 (manufactured by TSL Solution)" attached to the scanning electron microscope "ULTRA55 (manufactured by Zeiss)", magnification: 10000 times, scanning Step: 0.01 ⁇ m, and the definition of crystal grains was defined as grain boundaries with an orientation difference of 15 ° or more.
  • the maximum diameter (maximum length) of the nanocrystal grains (enclosed portion) confirmed in the EBSD image in FIG. 1 is as small as about 25 nm.
  • a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 40 mol% or more is more preferable.
  • the equilibrium precipitation amount of the gamma prime phase is more preferably 50 mol% or more, and even more preferably 60 mol% or more.
  • a particularly preferable equilibrium precipitation amount of the gamma prime phase is 63 mol% or more, more preferably 66 mol% or more, and even more preferably 68 mol% or more.
  • the upper limit of the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is not particularly limited, but is practically about 75 mol%.
  • the composition contains 0 to 0.300%, Zr: 0 to 0.300%, and the balance is composed of Ni and impurities.
  • each component having a preferable composition of the Ni-based superheat-resistant alloy of the present invention will be described (the unit of the component composition is "mass%").
  • C is contained as an element that enhances the castability of a Ni-based superheat resistant alloy.
  • Ni-based superheat-resistant alloys having a large amount of ⁇ 'phase are usually used as cast parts because plastic working is difficult, and a certain amount of C is added.
  • This added C remains as a carbide in the cast structure, and a part of it is formed as a coarse eutectic carbide.
  • coarse carbides serve as a crack starting point and a crack growth path when the Ni-based superheat-resistant alloy is plastically processed, especially when the Ni-based superheat-resistant alloy is plastically processed at room temperature. It has an adverse effect on sexuality.
  • the present invention in which a Ni-based superheat-resistant alloy having a large amount of ⁇ 'phase is produced by plastic working, not as a cast part, in the Ni-based superheat-resistant alloy. It is preferable to reduce C.
  • the C content is 0.25% or less. It is preferably 0.20% or less. More preferably, it is 0.15% or less.
  • C is also an element that enhances the strength of heat-resistant parts, and it is preferable that C is contained in consideration of producing or repairing such heat-resistant parts. According to the method for producing a Ni-based superheat-resistant alloy of the present invention, plastic working is possible even with an alloy having a high C content due to the effect of the nanocrystal grains described above.
  • C is assumed to be contained in an amount of 0.05% or more. It is preferably 0.06% or more, more preferably 0.07% or more, still more preferably 0.1% or more. Furthermore, C may be contained in an amount of more than 0.1%.
  • Chromium (Cr) Cr is an element that improves oxidation resistance and corrosion resistance. However, if Cr is excessively contained, an embrittled phase such as a ⁇ (sigma) phase is formed, which reduces the strength and hot workability at the time of material preparation. Therefore, Cr is preferably set to, for example, 8.0 to 25.0%. More preferably, it is 8.0 to 22.0%. The preferred lower limit is 9.0%, more preferably 9.5%. More preferably, it is 10.0%. The upper limit is preferably 18.0%, more preferably 16.0%. More preferably, it is 14.0%. Particularly preferably, it is 12.5%.
  • Mo Molybdenum
  • Mo contributes to the solid solution strengthening of the matrix and has the effect of improving the high temperature strength.
  • Mo is preferably 0 to 8.0% (addition-free (unavoidable impurity level) may be used). More preferably, it is 2.0 to 7.0%.
  • a further preferred lower limit is 2.5%, more preferably 3.0%. More preferably, it is 3.5%.
  • the upper limit is more preferably 6.0%, more preferably 5.0%.
  • Aluminum (Al) Al is an element that forms a ⁇ '(Ni 3 Al) phase, which is a strengthening phase, and improves high-temperature strength. However, excessive addition reduces hot workability during material preparation and causes material defects such as cracks during processing. Therefore, Al is preferably 0.5 to 8.0%. More preferably, it is 2.0 to 8.0%. A further preferred lower limit is 2.5%, more preferably 3.0%. It is even more preferably 4.0% and even more preferably 4.5%. Particularly preferably, it is 5.1%. Further, the upper limit is more preferably 7.5%, and more preferably 7.0%. More preferably, it is 6.5%.
  • the reduced Al content when the Cr content is reduced in order to ensure hot workability at the time of material preparation, the reduced Al content can be allowed. Then, for example, when the upper limit of Cr is set to 13.5%, the lower limit of the Al content is preferably set to 3.5%.
  • Ti Titanium (Ti) Like Al, Ti is an element that forms a ⁇ 'phase and strengthens the ⁇ 'phase by solid solution to increase high-temperature strength. However, excessive addition causes the ⁇ 'phase to become unstable at high temperatures, leading to coarsening at high temperatures, forming a harmful ⁇ (eta) phase, and impairing hot workability during material preparation. Therefore, Ti is preferably 0.4 to 7.0%, for example. Considering the balance with other ⁇ 'forming elements and Ni matrix, the preferable lower limit of Ti is 0.6%, more preferably 0.7%. More preferably, it is 0.8%. The upper limit is preferably 6.5%, more preferably 6.0%. It is more preferably 4.0%, and particularly preferably 2.0%.
  • Co Cobalt (Co) Co improves the stability of the structure and makes it possible to maintain the hot workability at the time of material preparation even if a large amount of Ti, which is a reinforcing element, is contained.
  • Co is one of the arbitrary elements that can be contained in the range of 28.0% or less, for example, by combining with other elements.
  • the preferable lower limit when adding Co is preferably 8.0%. More preferably, it is 10.0%.
  • the preferable upper limit of Co is 18.0%. More preferably, it is 16.0%. If Co may be added-free (the level of unavoidable impurities in the raw material) depending on the balance with the ⁇ 'forming element and the Ni matrix, the lower limit of Co is set to 0%.
  • W Tungsten
  • the upper limit is set to 15.0%.
  • the preferred upper limit is 13.0%, more preferably 11.0%, and even more preferably 9.0%.
  • the lower limit of W is preferably 1.0%.
  • the lower limit of W can be set to 3.0%, 5.0%, 7.0%.
  • W is preferably added in an amount of 0.8% or more. If W can be set to a non-addition level (a level of unavoidable impurities in the raw material) by sufficiently adding Mo, the lower limit of W is set to 0%.
  • Niobium (Nb) Like Al and Ti, Nb is one of the selective elements that forms the ⁇ 'phase and strengthens the ⁇ 'phase by solid solution to increase the high temperature strength. However, excessive addition of Nb forms a harmful delta phase, impairing hot workability during material preparation. Therefore, the upper limit of Nb is, for example, 4.0%. The preferred upper limit is 3.5%, more preferably 2.5%. In order to more reliably exert the effect of Nb, the lower limit of Nb is preferably 1.0%. It is preferably 2.0%. When Nb may be set to a non-addition level (unavoidable impurity level) by adding another ⁇ 'forming element, the lower limit of Nb is set to 0%.
  • Ta Tantalum (Ta) Like Al and Ti, Ta is one of the selective elements that forms the ⁇ 'phase and strengthens the ⁇ 'phase by solid solution to increase the high temperature strength. However, excessive addition of Ta causes the ⁇ 'phase to become unstable at high temperatures, leading to coarsening at high temperatures and forming a harmful ⁇ (eta) phase, which improves hot workability during material preparation. To spoil. Therefore, Ta is set to 5.0% or less, for example. It is preferably 4.0% or less, more preferably 3.0% or less, still more preferably 2.5% or less. In order to more reliably exert the effect of Ta, the lower limit of Ta is preferably 0.3%. Preferably, the lower limit of Ta can be 0.8%, 1.5%, 2.0%. If Ta may be an additive-free level (unavoidable impurity level) due to the addition of ⁇ 'forming elements such as Ti and Nb and the balance with the matrix, the lower limit of Ta is set to 0%.
  • Iron (Fe) Fe is one of the selective elements used as a substitute for expensive Ni and Co, and is effective in reducing the alloy cost. To obtain this effect, it is advisable to decide whether or not to add in combination with other elements. However, if Fe is excessively contained, an embrittled phase such as a ⁇ (sigma) phase is formed, which reduces the strength and hot workability at the time of material preparation. Therefore, the upper limit of Fe is, for example, 10.0%. The preferred upper limit is 9.0%, more preferably 8.0%. On the other hand, when Fe may be added-free level (unavoidable impurity level) depending on the balance with the ⁇ 'forming element and Ni matrix, the lower limit of Fe is set to 0%.
  • Vanadium (V) V is one of the selective elements useful for strengthening the solid solution of the matrix and strengthening the grain boundaries by forming carbides.
  • the upper limit of V is, for example, 1.2%.
  • the preferred upper limit is 1.0%, more preferably 0.8%.
  • the lower limit of V is preferably 0.5%. If V may be an additive-free level (unavoidable impurity level) due to the balance with other alloying elements in the alloy, the lower limit of V is set to 0%.
  • Hafnium (Hf) Hf is one of the selective elements useful for improving the oxidation resistance of alloys and strengthening grain boundaries by forming carbides.
  • the upper limit of Hf is, for example, 3.0%, preferably 2.0%, and more preferably 1.5%.
  • the lower limit of Hf may be set to 0.1%.
  • the lower limit of Hf can be 0.5%, 0.7%, 1.0%.
  • Hf may be added-free level (unavoidable impurity level) depending on the balance with other alloying elements in the alloy, the lower limit of Hf is set to 0%.
  • B B is an element that improves grain boundary strength and improves creep strength and ductility.
  • B has a large effect of lowering the melting point, and when a coarse boride is formed, the hot workability at the time of material preparation is hindered. Therefore, for example, it does not exceed 0.300%. It is good to control it like this.
  • the preferred upper limit is 0.200%, more preferably 0.100%. It is more preferably 0.050%, and particularly preferably 0.020%. In order to obtain the above effect, the content is preferably at least 0.001%. A more preferable lower limit is 0.003%, and even more preferably 0.005%. Particularly preferably, it is 0.010%. If B may be added-free level (unavoidable impurity level) depending on the balance with other alloying elements in the alloy, the lower limit of B is set to 0%.
  • the upper limit of Zr is, for example, 0.300%.
  • the preferred upper limit is 0.250%, more preferably 0.200%. It is more preferably 0.100%, and particularly preferably 0.050%.
  • the content is preferably at least 0.001%.
  • a more preferable lower limit is 0.005%, and even more preferably 0.010%.
  • Ni but it may contain unavoidable impurities.
  • the method of producing the first processed material to be subjected to the heat treatment described later is not particularly limited.
  • the first processed material can be obtained by a melting method in which molten metal is poured into a mold to produce an ingot. Then, for the production of the ingot, for example, vacuum melting may be applied by combining conventional methods such as vacuum arc remelting and electroslag remelting.
  • the first processed material may be obtained by a powder metallurgy method.
  • the above-mentioned ingot or alloy ingot material produced by the powder metallurgy method is subjected to hot working such as hot forging, hot rolling, and hot extrusion, and then cooled to form a predetermined shape.
  • it may be finished as a processed material in the shape of a bar material.
  • the processing temperature (processing start temperature) in hot processing shall be 900 ° C. or higher.
  • the temperature is preferably 950 ° C. or higher, more preferably 1000 ° C. or higher, and even more preferably 1050 ° C. or higher. And it is realistic that the temperature is 1250 ° C or lower at the highest.
  • heat treatment such as soaking can be performed between these operations.
  • soaking for example, holding at 1100 ° C. to 1280 ° C. for 5 to 60 hours
  • soaking may be performed to eliminate the elemental segregation of the ingot.
  • soaking may be performed after finishing the shape of a material (billet) to be subjected to hot extrusion.
  • the processed material after cooling can be machined (for example, cutting, polishing, grinding, etc. for dimensional adjustment and various maintenance), if necessary.
  • the conditions for hot extrusion are preferably an extrusion temperature (heating temperature of the material) of 1050 ° C. to 1200 ° C., an extrusion ratio of 4 to 20, and an extrusion speed (stem speed) of 5 to 80 mm / s.
  • the cross-sectional diameter of the extruded material is, for example, 10 mm or more or more than 20 mm. And, for example, it is 200 mm or less.
  • the cross-sectional diameter of the bar may be, for example, 150 mm or less, 100 mm or less, 50 mm or less, 30 mm or less, 10 mm or less. Keeping the cross-sectional diameter of the bar small is that the number of plastic workings (number of passes) can be reduced when making wire rods or thin wires with a smaller cross-sectional diameter by cold plastic working, which will be described later. preferable.
  • a first heat treatment material (referred to as “material”) having the component composition described above is prepared.
  • the Ni-based superheat-resistant alloy obtained by subjecting this material to strong processing for example, processing having a processing rate of 30% or more
  • the plastic working of (c) described later can be further processed. become. Therefore, cold working can be performed up to a larger working rate without performing heat treatment during plastic working.
  • the Ni-based superheat-resistant alloy targeted by the present invention contains 0.05 to 0.25% by mass of carbon.
  • Various carbides typified by MC and M 23 C 6 are formed in the structure of the material produced by subjecting the material having this composition to hot working such as hot forging, hot rolling, and hot extrusion. There is. Then, coarse carbide 2 is precipitated in the structure of the material 1 (FIG. 2).
  • the carbides are crushed by plastic working to become fine carbides 4, but the fine carbides are present in the processed structure as a carbide aggregate in which the fine carbides are connected in the extending direction of the structure.
  • Material defects 5 are formed between the fine carbides. If plastic working is further performed as it is, the defects 5 between the fine carbides 4 may spread and combine with the adjacent defects 5 to become the starting point of cracking. Therefore, by adjusting the morphology of the carbides in the structure before the cold plastic working is performed, it is possible to suppress the occurrence of defects 5 in the cold plastic working. For example, in the cross-sectional structure in the stretching direction, the defect rate can be 0.5 area% or less. Therefore, it is possible to suppress the occurrence of cracks starting from material defects.
  • the temperature of the material (referred to as "first processed material") that has been once cooled after the hot working is applied to 900 ° C. or higher.
  • the first heat-treated material is obtained by heating and heat-treating the material.
  • the reason why the morphology of the charcoal in the material structure is adjusted by this heat treatment and the occurrence of cracks during the plastic working is suppressed is that the first processed material (extruded material) before the cold plastic working is shown in FIG.
  • the relationship between the temperature of the heat treatment applied and the cold plastic workability surface reduction rate
  • Coarse MC is formed in the structure of the first processed material produced by hot processing at the above processing temperature. Then, a "composite carbide" formed by contacting the MC and the M 23 C 6 is formed. When plastic working is performed on such a structure, it is considered that M 23 C 6 and MC are separated at the interface and cause material defects. Therefore, by heating the first processed material to a heat treatment temperature of 900 ° C. or higher, most of the MC reacts with the gamma phase and changes its form to M 23 C 6 , especially at the position of the surface layer described above. The proportion of complex carbides is reduced.
  • the above-mentioned composite carbide is separated at the interface between the MC and M 23 C 6 like the above-mentioned first processed material.
  • the material being plastically worked tends to be cracked due to carbides, and the plastic workability tends to be lower than that of the stage 1 material.
  • the crystal grain size of the first heat-treated material after the heat treatment grows from that of the first processed material, and the plastic workability of the first heat-treated material is the first. Can be superior to that of processed materials.
  • the first heat-treated material according to the present invention has an area ratio of M 23 C 6 of 4.0 area% or less, 3.0 area% or less, or 2 in its cross-sectional structure. It is less than 0.0 area%. Preferably, for example, it is 1.5 area% or less, 1.0 area% or less, 0.7 area% or less, 0.5 area% or less. And more preferably, it is 0.3 area% or less, 0.2 area% or less, and 0.1 area% or less (including the case of 0 area%). Further, the first heat-treated material according to the present invention preferably has a number density of M 23 C 6 of 10.0 ⁇ 10-2 / ⁇ m 2 or less or 7.0 ⁇ in its cross-sectional structure.
  • the first heat-treated material according to the present invention preferably has an MC area ratio of 12.0 area% or less or 10.0 area% or less in its cross-sectional structure. And, for example, it is 8.0 area% or less, 6.0 area% or less, 5.0 area% or less. Further, for example, it is preferably 0.1 area% or more, 1.0 area% or more, and 2.0 area% or more. More preferably, for example, it is 2.5 area% or more, 3.1 area% or more, 3.2 area% or more, and 3.5 area% or more. And more preferably, it is 3.8 area% or more, 4.2 area% or more, and 4.5 area% or more.
  • the first heat-treated material according to the present invention preferably has a cross-sectional structure in which the number density of MCs is, for example, 5.0 ⁇ 10-2 / ⁇ m 2 or less, or 3.0 ⁇ 10-2.
  • Pieces / ⁇ m 2 or less 2.5 ⁇ 10-2 pieces / ⁇ m 2 or less. More preferably, for example, it is 2.0 ⁇ 10-2 pieces / ⁇ m 2 or less, 1.7 ⁇ 10-2 pieces / ⁇ m 2 or less, and 1.5 ⁇ 10-2 pieces / ⁇ m 2 or less.
  • 0.1 ⁇ 10 -2 pieces / ⁇ m 2 or more 0.5 ⁇ 10 -2 pieces / ⁇ m 2 or more, 1.0 ⁇ 10 -2 pieces / ⁇ m 2 or more.
  • the upper limit of the heat treatment temperature is not particularly limited, but is about 1250 ° C.
  • the heat treatment temperature is preferably a temperature exceeding 1150 ° C.
  • the heat treatment time can be, for example, 30 minutes or more, 45 minutes or more, 60 minutes or more depending on the size and shape of the first processed material, and the upper limit is 180 minutes or less, 120 minutes or less, 90 minutes or less. It may be decided as appropriate.
  • the heat treatment is preferably carried out in a vacuum, a reducing atmosphere, an inert atmosphere such as Ar, in order to avoid surface oxidation, but may be carried out in an oxidizing atmosphere (for example, an atmospheric atmosphere). When the heat treatment is performed in an oxidizing atmosphere, an oxidation scale is formed on the surface.
  • the heat treatment time is preferably completed in a short time, for example, 150 minutes or less, 100 minutes or less, 80 minutes or less.
  • the crystal grain size of the structure of the first heat-treated material (the average grain size of the maximum diameter of the crystal grains described later) can be set to 100 ⁇ m or less. It is preferably 80 ⁇ m or less, more preferably 60 ⁇ m or less, still more preferably 40 ⁇ m or less, still more preferably 20 ⁇ m or less.
  • the refinement of crystal grains is effective for the production of nanocrystal grains.
  • the crystal grains generated by recrystallization have less distortion in the grains, and the grain boundaries also increase by making the crystal grains finer. Processing strain is evenly applied to the entire structure.
  • the crystal grain size of the structure of the first heat-treated material can be made 1.4 ⁇ m or more. By growing the crystal grains, this acts on the adjustment of the distribution form of the carbides described above, and the plastic workability of the first heat-treated material is improved. It is preferably 1.5 ⁇ m or more, more preferably 1.8 ⁇ m or more.
  • the crystal grain size of the first heat treatment material grows to, for example, 2.0 ⁇ m or more, 3.0 ⁇ m or more, 4.0 ⁇ m or more, 5.0 ⁇ m or more.
  • the heat treatment temperature is a temperature exceeding 1150 ° C. or a temperature of 1200 ° C. or higher, it grows to a value of 7.0 ⁇ m or higher or 9.0 ⁇ m or higher.
  • the hardness of the first heat-treated material is not limited. Therefore, the cooling after the above heat treatment may be rapid cooling, air cooling, air cooling, furnace cooling, or the like.
  • the hardness of the first heat-treated material can be, for example, 460 HV or less or 450 HV or less. More preferably, it is 430 HV or less. It is more preferably 400 HV or less, and even more preferably 380 HV or less.
  • the lower limit of the hardness of the first heat-treated material is not particularly limited, but is realistically about 250 HV. Then, the hardness of the first heat-treated material can be set to 300 HV or more. The hardness of the first heat-treated material can be measured in cross section thereof.
  • (C) Step of Producing Second Processed Material cold plastic working is performed on the above material (first heat-treated material). Since the above-mentioned material is excellent in plastic workability and is also excellent in plastic workability during plastic working, it is possible to perform a plurality of times of cold plastic working in which the cumulative work rate from the material is 40% or more.
  • the present invention produces a Ni-based superheat resistant alloy by "cold" plastic working, as opposed to conventional "hot” plastic working.
  • a cumulative working rate of 40% or more can be obtained by cold plastic working, and the alloy is processed by hot plastic working.
  • the plastic working temperature in the present invention is preferably "500 ° C. or lower". It is more preferably 300 ° C. or lower, still more preferably 100 ° C. or lower, and even more preferably 50 ° C. or lower (for example, room temperature).
  • the method for producing a Ni-based superheat-resistant alloy of the present invention can be applied to the production of various shapes. Although it is suitable for the wire rod form, it can also be applied to a plate material, a strip material, and the like. Therefore, the Ni-based superheat-resistant alloy produced by the production method of the present invention has an intermediate product shape of a wire material, a sheet material, and a strip material, and also has a wire material. It may be the final product shape of a product), a sheet product, or a strip product. Regarding the relationship between the dimensions of the plate material (thin plate) and the strip material (thin strip), the wire diameter (diameter) of the wire rod (thin wire) can be read as the plate thickness or the strip thickness.
  • the hot-extruded material of the Ni-based superheat-resistant alloy is a bar material
  • the bar material processing for compressing the cross section can be performed.
  • the processing rate is expressed by the surface reduction rate when the bar is swaged or the die is drawn.
  • the surface reduction rate is the relationship between the cross-sectional area A 0 of the bar material before plastic working and the cross-sectional area A 1 of the wire rod or thin wire after plastic working. [(A 0- A 1 ) / A 0 ] x 100 (%) (1) It is calculated by the formula of.
  • the processing rate is expressed as a rolling reduction rate.
  • the cumulative working rate indicates the working rate of the final work piece with respect to the material when plastic working is performed a plurality of times or over a plurality of passes.
  • the cumulative working rate from the above-mentioned cold plastic working material is increased to 40% or more.
  • the plastic working at this working rate is not completed by one plastic working, but can be completed by dividing into a plurality of plastic working. No heat treatment is performed during multiple plastic workings.
  • the heat treatment referred to here is a heat treatment in a high temperature region where recovery or recrystallization occurs, and is, for example, a heat treatment for heating to a temperature exceeding 500 ° C.
  • heat treatment is not required between the cold working passes, and a plurality of cold strong working can be continuously performed to increase the cumulative working rate (cumulative surface reduction rate).
  • the formation of nanocrystal grains can be observed in the structure.
  • the cumulative working rate should be 40% or more.
  • the cumulative processing rate is preferably 45% or more, more preferably 50% or more, still more preferably 55% or more.
  • the upper limit of the cumulative processing rate is not particularly limited, but can be, for example, about 70%. Further, it can be about 80% and about 90%. It can exceed 90%.
  • plastic working is performed up to the target dimensions (final product dimensions).
  • the hardness of the material of the final product size can be 500 HV or more.
  • the processing rate (surface reduction rate) by one plastic working (pass) is preferably 30% at maximum. More preferably, it can be up to 28%.
  • pass used in the present specification, in the above-mentioned types of plastic working such as swaging, die wire drawing, and rolling, when plastic working is performed by one (or a pair of) dies or rolls, "1" is used. It can be called a "pass”.
  • 1 pass refers to the above-mentioned one-time "plastic working”.
  • the material of the Ni-based super heat-resistant alloy is a bar
  • plastic working that compresses the cross-sectional area of the bar from the peripheral surface of the bar toward the axis is effective.
  • a plastic working method in which pressure is evenly applied to the entire circumference of the bar to be plastic working is advantageous.
  • a specific example of this is swaging.
  • the swaging process is preferable for the formation of nanocrystal grains because the peripheral surface of the bar is forged while rotating a plurality of dies surrounding the entire circumference of the bar.
  • other plastic working such as cassette roller die drawing and hole type die drawing can also be applied.
  • the alloy obtained by the above-mentioned cold plastic working can be used as the final product shape.
  • it can be a "thin line", a "thin plate", or a "thin band”.
  • the thin wire has a wire diameter (diameter) of 5 mm or less, 4 mm or less, 3 mm or less, and finally 2 mm or less and 1 mm or less.
  • the thin plate and the thin band have a thickness of, for example, 5 mm or less, 4 mm or less, 3 mm or less, and finally 2 mm or less and 1 mm or less.
  • the thin wire, the thin plate, and the thin band are longer in length, for example, 50 times or more, 100 times or more, and 300 times or more with respect to the above wire diameter and thickness.
  • the alloy in this case is, for example, a linear structure in which the ⁇ phase and the ⁇ 'phase in the structure extend in the stretching direction.
  • the hardness of the alloy is 500 HV or more.
  • processing defects are present in the alloy.
  • the defect rate is a processing defect exceeding 0.5 area%.
  • it is 1.0 area% or less. The existence of such processing defects does not cause any problem in that no further plastic working is performed.
  • a desired equiaxed crystal structure can be obtained by performing heat treatment at a temperature of 900 ° C. or higher (for example, holding at a temperature of 900 ° C. to 1200 ° C. for 30 minutes to 3 hours).
  • the hardness can be adjusted to less than 500 HV, 450 HV or less, and 420 HV or less. And, for example, the hardness is 300 HV or more or 350 HV or more. This makes it easy to bend or cut the final product into a form suitable for the transportation form and usage form.
  • the processing defect can be repaired by this heat treatment, and for example, the defect rate can be reduced to 0.5 area% or less in the cross-sectional structure including the central axis in the length direction (that is, the plastic working direction) of the alloy. Then, combined with the effect of the heat treatment performed in the state of the material before plastic working, the above defect rate can be further reduced to 0.4 area% or less, 0.3 area% or less, and 0.2 area% or less.
  • This heat treatment can be performed when it is desired to reduce processing defects in the usage form of the Ni-based superheat resistant alloy.
  • the crystal grains in the equiaxed crystal structure are grown by performing the above heat treatment.
  • the grain size of the crystal grains may reach the maximum wire diameter. Then, if the effect of suppressing the coarsening of the crystal grains (pinning effect) effectively functions by the carbide aggregates connected in the stretching direction, the growth of the crystal grains is suppressed.
  • the size of the crystal grains after the heat treatment is the average particle size in the cross-sectional structure, for example, 100 ⁇ m or less, 75 ⁇ m or less, 50 ⁇ m or less, 25 ⁇ m or less, 10 ⁇ m or less.
  • the final heat treatment is preferably carried out in an inert atmosphere such as vacuum, reducing atmosphere or Ar in order to avoid surface oxidation, but may be carried out in an oxidizing atmosphere (for example, atmospheric atmosphere).
  • an oxidation scale is formed on the surface. If it may interfere with the quality of the product, the formed oxide scale may be removed mechanically or chemically, for example by polishing or grinding. In the case of wire rod production, it is preferable to remove the scale by using centerless polishing.
  • the surface of the final product can be mechanically or chemically finished by, for example, polishing or grinding.
  • Ni-based super heat-resistant alloy according to the present invention has been described above. According to the present invention, since plastic working of a Ni-based superheat resistant alloy having a large cumulative working rate (for example, 40% or more) can be performed at a temperature of 500 ° C. or lower, it is complicated to repeat hot working and heat treatment. Strong cold plastic working is possible without the need for various manufacturing processes, and heat treatment between plastic working can be omitted. Therefore, the simplification of the process can be achieved and the manufacturing cost can be reduced. Further, if necessary, a product having a defect rate of 1.0 area% or less and few processing defects, particularly a wire rod, can be obtained. This effect is particularly remarkable for Ni-based superheat-resistant alloys having a large carbon content in which processing defects are likely to occur.
  • a defect rate for example, 40% or more
  • (A) Step of Producing First Processed Material The molten metal prepared by vacuum melting was cast to prepare an ingot A of a columnar Ni-based superheat resistant alloy having a diameter of 100 mm and a mass of 10 kg.
  • the component composition of ingot A is shown in Table 1 (mass%).
  • Table 1 also shows the " ⁇ 'molar rate" of the above ingot A. This value was calculated using commercially available thermodynamic equilibrium calculation software "JMatPro (Version 8.0.1, a product of Center Software Ltd.)". The content of each element listed in Table 1 was input to this thermodynamic equilibrium calculation software to obtain the above " ⁇ 'molar ratio" (%).
  • the ingot A having this composition is heat-treated at a holding temperature of 1200 ° C. and a holding time of 8 hours, cooled in a furnace, and then a cylindrical material having a length of 150 mm and a diameter of 60 mm is collected in a direction parallel to the length of the ingot A. did.
  • This cylindrical material was sealed in SUS304 capsules and subjected to hot extrusion.
  • the conditions for hot extrusion were an extrusion temperature of 1100 ° C., an extrusion ratio of 10 (including capsules), and an extrusion stem speed of 15 mm / s. Hot extrusion was performed, the mixture was cooled to room temperature, and then the capsule material was removed to obtain an extruded material (first processed material) having a diameter of 27 mm.
  • Materials 1 to 7 were cut in half parallel to the axial direction, and the microstructure (crystal grain size, carbide morphology) and hardness of the cut surface were evaluated.
  • the cross-sectional microstructures of the cut surfaces as observed by scanning electron microscopes (SEM images) of materials 1 to 7 are shown in the order of FIGS. 4 to 10.
  • the magnification of the cross-sectional microstructure can be basically 2000 times.
  • the crystal grain size is large, the magnification can be reduced in order to confirm a larger number of crystal grains.
  • the crystal grain size by EBSD described later exceeds 8 ⁇ m, the magnification is 1000 times. (Materials 6 and 7).
  • the observation location was a position within a distance of D / 4 (D is the diameter of the extruded material) from the surface of the material toward the axis on the above-mentioned cut surface.
  • D is the diameter of the extruded material
  • Various carbide Each microstructure (MC, M 23 C 6, etc.) where it was observed (dispersion in the figure), the microstructure of the material 6, 7 of the heat treatment temperature is 1200 ° C., M 23 C No. 6 was substantially not confirmed (0.1 ⁇ 10-2 pieces / ⁇ m 2 or less).
  • the hardness was evaluated at a position within a distance of D / 2 from the surface of the material toward the axis (that is, the position of the axis) on the above-mentioned cut surface.
  • the distribution form of MC is a mapping diagram of Nb, which is a metal element that composes it, and that of M 23 C 6 is It can also be confirmed in the Cr mapping diagram.
  • the Nb mapping diagram and the Cr mapping diagram are shown in FIGS. 4 to 10.
  • Cr mapping diagram of FIGS. 9 (material 6) and 10 (material 7) Cr is evenly distributed over the entire surface (that is, Cr is solid-solved in the base), and Cr is unevenly distributed. (Ie, no carbides of Cr) were found. Then, the mapping diagram of FIGS.
  • 4 to 10 is set as one field of view (50 ⁇ m ⁇ 65 ⁇ m at 2000 times magnification, 100 ⁇ m ⁇ 130 ⁇ m at 1000 times magnification), and the area ratio and number density of carbides confirmed in this one field of view are shown in this one field of view. (That is, 100 ⁇ m ⁇ 130 ⁇ m at a magnification of 2000 times, 200 ⁇ m ⁇ 260 ⁇ m at a magnification of 1000 times), and the average value of these four fields of view is the value according to the present invention. It was determined as the carbide form of the heat treatment material of 1.
  • the EBSD measurement conditions are as follows: Magnification: 2000 using the EBSD measurement system "Aztec Version 3.2 (Oxford Instruments)" attached to the above scanning electron microscope (JIB-4700F (JEOL Ltd.)). Double (1000 times for materials 6 and 7), scan step: 0.1 ⁇ m, and the definition of crystal grains was defined as grain boundaries with an orientation difference of 15 ° or more. The EBSD images at this time are also shown in FIGS. 4 to 10.
  • the grains excluding those of the MC carbide confirmed by the above EPMA are defined as crystal grains, and for these crystal grains, the maximum diameter (maximum length) of each crystal grain is used. ) And the number of crystals, the crystal grain size distribution was confirmed, and the average diameter of the maximum diameter of the crystal grains was determined. Then, the average diameter of the maximum diameters of the crystal grains obtained in the EBSD image of this one field of view is obtained in the same manner as in the case of the above-mentioned carbide form in another three fields of view vertically and horizontally adjacent to this one field of view. The average value of the values for the four fields of view was determined as the crystal grain size of the first heat-treated material according to the present invention.
  • FIGS. 11 and 11 show the relationship between the heat treatment temperature and the carbide morphology (area ratio, number density), crystal grain size and hardness, except for the material 7 (air-cooled). 12, FIG. 13 and FIG. 14 are shown in this order.
  • the area ratio and number density of MC and the area ratio and number density of M 23 C 6 are reversed between 1100 ° C. and 1150 ° C., and the MC However, the area ratio and the number density are high.
  • stage 1 the relationship between the temperature of the heat treatment applied to the extruded material before the cold plastic working and the cold plastic working (surface reduction rate) is shown in FIG. From FIG. 3, by heat-treating the extruded material, the workability of the material was dramatically improved (stage 1). Then, although the workability tends to decrease once when the heat treatment temperature exceeds 1000 ° C. (stage 2), the initial workability is maintained and the heat treatment temperature rises again when the heat treatment temperature exceeds 1150 ° C. The workability was further improved (stage 3).
  • Ni-based superheat-resistant alloy As described above, it has been shown that a thin wire of a Ni-based superheat-resistant alloy can be produced by cold plastic working according to the examples.
  • the Ni-based superheat-resistant alloy produced by the production method of the present invention can be processed into a wire rod or the like having an arbitrary wire diameter by plastic working in the cold.
  • this embodiment was performed on the production of wire rods, it can also be applied to the production of other shapes such as plate materials.

Abstract

Provided are: a method for producing a Ni-based super-heat-resistant alloy having a constituent composition such that the equilibrium precipitation amount of a gamma-prime phase at 700ºC is 35 mol% or more; and a Ni-based super-heat-resistant alloy. This method includes: (a) a step for producing a first processed material by subjecting a material, in which the carbon content is 0.05-0.25 mass% and which has a constituent composition such that the equilibrium precipitation amount of a gamma-prime phase at 700ºC is 35 mol% or more, to plastic working at a temperature of 900ºC or higher and then cooling the same; and (b) a step for producing a first heat treated material by carrying out a heat treatment by heating the first processed material at a temperature of 900°C or higher. This method further includes (c) a step for producing a second processed material by subjecting the first heat treated material to plastic working at a temperature of 500°C or lower. The present invention is also a Ni-based super-heat-resistant alloy which is for cold plastic working, which has the foregoing constituent composition and which has a cross-sectional structure in which the areal ratio of M23C6 is 4.0 area% and the average particle diameter of the maximum diameter of crystal grains is 1.4-100 μm.

Description

Ｎｉ基超耐熱合金の製造方法およびＮｉ基超耐熱合金Manufacturing method of Ni-based super heat-resistant alloy and Ni-based super heat-resistant alloy
　本発明は、Ｎｉ基超耐熱合金を製造する方法およびＮｉ基超耐熱合金に関するものであり、詳細には７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有するＮｉ基超耐熱合金を製造する方法およびＮｉ基超耐熱合金に係るものである。 The present invention relates to a method for producing a Ni-based superheat-resistant alloy and, specifically, a Ni-based superheated alloy having a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more. It relates to a method for producing a heat-resistant alloy and a Ni-based super heat-resistant alloy.
　航空機エンジンや発電用のガスタービンに用いられる耐熱部品として、例えば、インコネル（登録商標）７１８合金のようなＮｉ基超耐熱合金が多く用いられている。ガスタービンの高性能化と低燃費化に伴って、高い耐熱温度を有する耐熱部品が求められている。Ｎｉ基超耐熱合金の耐熱性（高温強度）を向上させるためには、Ｎｉ３Ａｌを主組成とする金属間化合物の析出強化相であるガンマプライム（以下、「γ’」とも記す。）相の量を増やすことが最も有効である。そして、Ｎｉ基超耐熱合金が、更に、γ’生成元素であるＡｌ、Ｔｉ、Ｎｂを含有することで、Ｎｉ基超耐熱合金の高温強度をさらに向上させることができる。今後、高耐熱性、高強度を満足させるために、γ’相の量がより多いＮｉ基超耐熱合金が求められる。 As heat-resistant parts used in aircraft engines and gas turbines for power generation, for example, Ni-based super heat-resistant alloys such as Inconel (registered trademark) 718 alloy are often used. Along with higher performance and lower fuel consumption of gas turbines, heat-resistant parts having a high heat-resistant temperature are required. In order to improve the heat resistance (high temperature strength) of Ni-based superheat-resistant alloys, the gamma prime (hereinafter, also referred to as “γ'”) phase, which is a precipitation strengthening phase of an intermetallic compound having Ni 3 Al as a main composition. It is most effective to increase the amount of. The Ni-based superheat-resistant alloy further contains the γ'forming elements Al, Ti, and Nb, so that the high-temperature strength of the Ni-based superheat-resistant alloy can be further improved. In the future, in order to satisfy high heat resistance and high strength, a Ni-based super heat resistant alloy having a larger amount of γ'phase will be required.
　しかし、Ｎｉ基超耐熱合金は、γ’相の増加と共に、熱間加工の変形抵抗が大きくなり、難加工であることが知られている。とりわけ、γ’相の量が３５～４０モル％以上のγ’モル率になると加工性は特に低下する。例えば、インコネル（登録商標）７１３Ｃ合金、ＩＮ９３９、ＩＮ１００、Ｍａｒ－Ｍ２４７等の合金は、特別にγ’相が多く、塑性加工が不可能とされ、通常は鋳造合金として鋳造まま（ａｓ－ｃａｓｔ）で使用されている。 However, it is known that Ni-based superheat-resistant alloys are difficult to process because the deformation resistance of hot processing increases as the γ'phase increases. In particular, when the amount of the γ'phase is 35 to 40 mol% or more, the processability is particularly lowered. For example, alloys such as Inconel (registered trademark) 713C alloy, IN939, IN100, and Mar-M247 have a particularly large number of γ'phases, which makes plastic working impossible, and are usually cast as cast alloys (as-cast). Used in.
　このようなＮｉ基超耐熱合金の熱間塑性加工性を向上させる提案として、特許文献１では、γ’モル率が４０モル％以上となる組成を有するＮｉ基超耐熱合金インゴットを加工率５％以上３０％未満で冷間加工を行った後にγ’固溶温度を超える温度で熱処理する製造方法が記載されている。この方法は、冷間加工工程と熱処理工程との組合せにより、Ｎｉ基超耐熱合金に熱間加工を適用することが可能な９０％以上の再結晶率を得るものである。 As a proposal for improving the hot plastic workability of such a Ni-based superheat-resistant alloy, in Patent Document 1, a Ni-based superheat-resistant alloy ingot having a composition having a γ'molar ratio of 40 mol% or more is processed at a processing rate of 5%. A manufacturing method is described in which cold working is performed at a temperature of less than 30% and then heat treatment is performed at a temperature exceeding the γ'solid solution temperature. In this method, a recrystallization rate of 90% or more, which enables hot working to be applied to a Ni-based superheat-resistant alloy, is obtained by combining a cold working step and a heat treatment step.
　また、近年、上述したγ’相の量が多いＮｉ基超耐熱合金の耐熱部品を補修したり、または、その耐熱部品自体を３次元成形で作製したりするニーズが高まっている。その場合の造形素材としてＮｉ基超耐熱合金の細線が求められている。この細線は、ばね等の部品形状に加工して使用することもできる。Ｎｉ基超耐熱合金の細線の線径（直径）は、例えば、５ｍｍ以下、更には３ｍｍ以下という細いものである。このような細線は、例えば、線径が１０ｍｍ以下の「線材」を中間製品として準備し、この線材に塑性加工を行って作製することが効率的である。この中間製品である「線材」も、塑性加工によって得ることができれば、Ｎｉ基超耐熱合金の細線を効率的に製造することができる。
　このような超耐熱合金の細線の製造方法として、線径が５ｍｍ以上の鋳造ワイヤを出発材にして、これら鋳造ワイヤを束ねたものを熱間押出した後、分離する手法が提案されている（特許文献２）。 Further, in recent years, there is an increasing need for repairing heat-resistant parts of the above-mentioned Ni-based superheat-resistant alloy having a large amount of γ'phase, or manufacturing the heat-resistant parts themselves by three-dimensional molding. A fine wire of Ni-based super heat-resistant alloy is required as a modeling material in that case. This thin wire can also be used by processing it into a component shape such as a spring. The wire diameter (diameter) of the thin wire of the Ni-based superheat-resistant alloy is, for example, as thin as 5 mm or less and further 3 mm or less. For such a thin wire, for example, it is efficient to prepare a "wire rod" having a wire diameter of 10 mm or less as an intermediate product and perform plastic working on the wire rod to produce it. If this intermediate product, "wire rod", can also be obtained by plastic working, fine wires of Ni-based superheat-resistant alloy can be efficiently produced.
As a method for producing such a fine wire of a super heat-resistant alloy, a method has been proposed in which a cast wire having a wire diameter of 5 mm or more is used as a starting material, a bundle of these cast wires is hot-extruded, and then separated. Patent Document 2).
国際公開第２０１６／１２９４８５号International Publication No. 2016/129485 米国特許第４７７７７１０号明細書U.S. Pat. No. 4777710
　特許文献１の方法は、熱間加工を適用するＮｉ基超耐熱合金には効果がある。しかし、上記のとおりＮｉ基超耐熱合金はγ’相の量の増加と共に、熱間塑性加工性が低下する。特許文献２の手法は、限られた成分組成においては細線の製造に効果的なものであるが、その成分組成にしか適用できず、γ’相の量が後述する「３５モル％以上」のＮｉ基超耐熱合金にもなると、これを熱間塑性加工して細線まで加工することは極めて困難である。また、特許文献２の手法は、工程が複雑で、製造コストが大きくなる等の問題があった。また、細線や線材を作製するにおいては、その途中工程で割れが発生すると加工率が制限されて、所定の線径にまで塑性加工できないという問題も考えられた。 The method of Patent Document 1 is effective for Ni-based superheat-resistant alloys to which hot working is applied. However, as described above, the hot plastic workability of the Ni-based superheat-resistant alloy decreases as the amount of the γ'phase increases. The method of Patent Document 2 is effective for producing fine wires in a limited component composition, but can be applied only to the component composition, and the amount of γ'phase is "35 mol% or more" described later. When it comes to a Ni-based super heat-resistant alloy, it is extremely difficult to hot-plasticize it to process fine wires. Further, the method of Patent Document 2 has a problem that the process is complicated and the manufacturing cost is high. Further, in producing thin wires and wire rods, there is a problem that if cracks occur in the middle of the process, the processing rate is limited and plastic working cannot be performed to a predetermined wire diameter.
　本発明の目的は、従来とは全く異なる斬新な手法を用いて、塑性加工性に優れたＮｉ基超耐熱合金の製造方法と、Ｎｉ基超耐熱合金とを提供することであり、とりわけＮｉ基超耐熱合金の細線を製造できる新たな方法と、Ｎｉ基超耐熱合金とを提供することである。本発明のさらに他の目的は、線径の小さいＮｉ基超耐熱合金でも、欠陥の少ない細線を少ない工数によりコストを低減して製造できる方法と、Ｎｉ基超耐熱合金とを提供することである。 An object of the present invention is to provide a method for producing a Ni-based superheat-resistant alloy having excellent plastic workability and a Ni-based superheat-resistant alloy, in particular, using a novel method completely different from the conventional one. It is to provide a new method capable of producing a fine wire of a super heat-resistant alloy and a Ni-based super heat-resistant alloy. Still another object of the present invention is to provide a method capable of producing a thin wire having few defects with a small number of man-hours at a reduced cost even with a Ni-based superheat-resistant alloy having a small wire diameter, and a Ni-based superheat-resistant alloy. ..
　本発明の一観点によれば、Ｎｉ基超耐熱合金を製造する方法が提供される。この方法は、
（ａ）炭素含有量が０．０５～０．２５質量％であり、かつ７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有する材料に対して、９００℃以上の温度で塑性加工を行なった後に冷却して、第１の加工材を作製する工程と、
（ｂ）第１の加工材を９００℃以上の温度に加熱して熱処理を行い、第１の熱処理材を作製する工程と
を含むものである。 According to one aspect of the present invention, there is provided a method for producing a Ni-based superheat resistant alloy. This method
(A) A temperature of 900 ° C. or higher with respect to a material having a carbon content of 0.05 to 0.25% by mass and a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more. The process of producing the first processed material by cooling after performing plastic working in
(B) It includes a step of heating the first processed material to a temperature of 900 ° C. or higher to perform heat treatment to prepare the first heat-treated material.
　一具体例によれば、（ｃ）第１の熱処理材に、５００℃以下の温度で塑性加工を行ない、第２の加工材を作製する工程と
を含むものである。 According to one specific example, (c) the first heat-treated material includes a step of plastically working at a temperature of 500 ° C. or lower to produce a second processed material.
　一具体例によれば、（ｄ）第２の加工材に、９００℃以上の温度で熱処理を行う工程をさらに含むことが好ましい。 According to one specific example, it is preferable that (d) the second processed material further includes a step of performing a heat treatment at a temperature of 900 ° C. or higher.
　また、一具体例によれば、Ｎｉ基超耐熱合金が、質量％で、
　　Ｃ：０．０５～０．２５％、
　　Ｃｒ：８．０～２５．０％、
　　Ａｌ：０．５～８．０％、
　　Ｔｉ：０．４～７．０％、
　　Ｃｏ：０～２８．０％、
　　Ｍｏ：０～８．０％、
　　Ｗ：０～１５．０％、
　　Ｎｂ：０～４．０％、
　　Ｔａ：０～５．０％、
　　Ｆｅ：０～１０．０％、
　　Ｖ：０～１．２％、
　　Ｈｆ：０～３．０％、
　　Ｂ：０～０．３００％、
　　Ｚｒ：０～０．３００％
を含み、残部がＮｉおよび不純物からなる組成を有することが好ましい。 Further, according to one specific example, the Ni-based superheat-resistant alloy is in mass%.
C: 0.05-0.25%,
Cr: 8.0-25.0%,
Al: 0.5-8.0%,
Ti: 0.4-7.0%,
Co: 0-28.0%,
Mo: 0-8.0%,
W: 0 to 15.0%,
Nb: 0-4.0%,
Ta: 0-5.0%,
Fe: 0 to 10.0%,
V: 0-1.2%,
Hf: 0-3.0%,
B: 0 to 0.300%,
Zr: 0 to 0.300%
It is preferable that the balance is composed of Ni and impurities.
　また、本発明の一観点によれば、Ｎｉ基超耐熱合金が提供される。この合金は、冷間塑性加工用のものであって、
　炭素含有量が０．０５～０．２５質量％であり、かつ７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有し、
　断面組織において、Ｍ２３Ｃ６の面積率が４．０面積％以下で、結晶粒の最大径の平均粒径が１．４～１００μｍのものである。 Further, according to one aspect of the present invention, a Ni-based superheat resistant alloy is provided. This alloy is for cold plastic working and
It has a component composition having a carbon content of 0.05 to 0.25% by mass and an equilibrium precipitation amount of the gamma prime phase at 700 ° C. of 35 mol% or more.
In the cross-sectional structure, the area ratio of M 23 C 6 is 4.0 area% or less, and the average particle size of the maximum diameter of the crystal grains is 1.4 to 100 μm.
　一具体例によれば、Ｎｉ基超耐熱合金の硬さが４６０ＨＶ以下であることが好ましい。 According to one specific example, the hardness of the Ni-based superheat-resistant alloy is preferably 460 HV or less.
　また、一具体例によれば、Ｎｉ基超耐熱合金が、質量％で、
　　Ｃ：０．０５～０．２５％、
　　Ｃｒ：８．０～２５．０％、
　　Ａｌ：０．５～８．０％、
　　Ｔｉ：０．４～７．０％、
　　Ｃｏ：０～２８．０％、
　　Ｍｏ：０～８．０％、
　　Ｗ：０～１５．０％、
　　Ｎｂ：０～４．０％、
　　Ｔａ：０～５．０％、
　　Ｆｅ：０～１０．０％、
　　Ｖ：０～１．２％、
　　Ｈｆ：０～３．０％、
　　Ｂ：０～０．３００％、
　　Ｚｒ：０～０．３００％
を含み、残部がＮｉおよび不純物からなる組成を有することが好ましい。 Further, according to one specific example, the Ni-based superheat-resistant alloy is in mass%.
C: 0.05-0.25%,
Cr: 8.0-25.0%,
Al: 0.5-8.0%,
Ti: 0.4-7.0%,
Co: 0-28.0%,
Mo: 0-8.0%,
W: 0 to 15.0%,
Nb: 0-4.0%,
Ta: 0-5.0%,
Fe: 0 to 10.0%,
V: 0-1.2%,
Hf: 0-3.0%,
B: 0 to 0.300%,
Zr: 0 to 0.300%
It is preferable that the balance is composed of Ni and impurities.
　以下の非限定的な具体例の説明および添付の図面を参照することにより、本発明の利点、特徴及び詳細が明らかになるであろう。 The advantages, features and details of the present invention will be clarified by referring to the following explanation of non-limiting examples and the accompanying drawings.
減面率３１％の塑性加工を行なったＮｉ基超耐熱合金の断面ミクロ組織の電子線後方散乱回折（ＥＢＳＤ）像。An electron backscatter diffraction (EBSD) image of a cross-sectional microstructure of a Ni-based superheat-resistant alloy that has been plastically processed with a surface reduction rate of 31%. 本発明に係る第１の加工材に塑性加工を行ったときの組織中の炭化物を説明する図。The figure explaining the carbide in the structure when plastic working is performed on the 1st processed material which concerns on this invention. 本発明に係る第１の加工材に熱処理を行ったときの第１の熱処理材（素材）の冷間塑性加工性を説明する図。The figure explaining the cold plastic workability of the 1st heat-treated material (material) when the 1-process material which concerns on this invention is heat-treated. 実施例１における素材１（熱処理なし）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。Cross-sectional microstructure of material 1 (without heat treatment), EPMA mapping diagram of Cr and Nb, and EBSD image of Material 1 in Example 1. 実施例１における素材２（熱処理温度１０００℃）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。The cross-sectional microstructure of the material 2 (heat treatment temperature 1000 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image. 実施例１における素材３（熱処理温度１０５０℃）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。The cross-sectional microstructure of the material 3 (heat treatment temperature 1050 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image. 実施例１における素材４（熱処理温度１１００℃）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。The cross-sectional microstructure of the material 4 (heat treatment temperature 1100 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image. 実施例１における素材５（熱処理温度１１５０℃）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。Cross-sectional microstructure of material 5 (heat treatment temperature 1150 ° C.) in Example 1, EPMA mapping diagram of Cr and Nb, and EBSD image. 実施例１における素材６（熱処理温度１２００℃）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。The cross-sectional microstructure of the material 6 (heat treatment temperature 1200 ° C.) in Example 1, the EPMA mapping diagram of Cr and Nb, and the EBSD image. 実施例１における素材７（熱処理温度１２００℃、空冷）の断面ミクロ組織、ＣｒとＮｂのＥＰＭＡマッピング図およびＥＢＳＤ像。Cross-sectional microstructure of material 7 (heat treatment temperature 1200 ° C., air cooling) in Example 1, EPMA mapping diagram of Cr and Nb, and EBSD image. 実施例１で第１の加工材に熱処理を行って第１の熱処理材（素材）を作製したときの、熱処理温度と炭化物の面積率との関係を示す図。The figure which shows the relationship between the heat treatment temperature and the area ratio of a carbide when the 1st heat treatment material (material) is prepared by performing heat treatment on the 1st processed material in Example 1. FIG. 実施例１で第１の加工材に熱処理を行って第１の熱処理材（素材）を作製したときの、熱処理温度と炭化物の個数密度との関係を示す図。FIG. 5 is a diagram showing the relationship between the heat treatment temperature and the number density of carbides when the first heat-treated material (material) is produced by heat-treating the first processed material in Example 1. 実施例１で第１の加工材に熱処理を行って第１の熱処理材（素材）を作製したときの、熱処理温度と結晶粒径との関係を示す図。The figure which shows the relationship between the heat treatment temperature and the crystal grain size when the first heat treatment material (material) was prepared by performing heat treatment on the 1st processed material in Example 1. FIG. 実施例１で第１の加工材に熱処理を行って第１の熱処理材（素材）を作製したときの、熱処理温度と硬さとの関係を示す図。The figure which shows the relationship between the heat treatment temperature and hardness at the time of producing the 1st heat treatment material (material) by performing heat treatment on the 1st processed material in Example 1. FIG.
　本発明は、従来の熱間塑性加工とは異なる新しいアプローチによって、塑性加工性に優れたＮｉ基超耐熱合金を製造できる新たな方法と、Ｎｉ基超耐熱合金とを提供するものである。
　本発明者は、γ’相の量が多いＮｉ基超耐熱合金の塑性加工性について研究した。その結果、熱間塑性加工の後に、再度加熱して熱処理を行なったＮｉ基超耐熱合金に冷間塑性加工を行なうことが可能である現象を突きとめた。
　その際、３０％以上の加工率での冷間塑性加工により、Ｎｉ基超耐熱合金の組織中にナノ結晶粒が生成されることを見いだした。このナノ結晶粒の生成がＮｉ基超耐熱合金の塑性加工性の飛躍的向上に寄与しているものと推察される。 The present invention provides a new method capable of producing a Ni-based superheat-resistant alloy having excellent plastic workability and a Ni-based superheat-resistant alloy by a new approach different from the conventional hot plastic working.
The present inventor has studied the plastic workability of a Ni-based superheat resistant alloy having a large amount of γ'phase. As a result, it was found that it is possible to perform cold plastic working on a Ni-based superheat-resistant alloy that has been heat-treated by heating again after hot plastic working.
At that time, it was found that nanocrystal grains were generated in the structure of the Ni-based superheat-resistant alloy by cold plastic working at a processing rate of 30% or more. It is presumed that the formation of these nanocrystal grains contributes to the dramatic improvement in the plastic workability of the Ni-based superheat-resistant alloy.
　したがって、本発明による７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有するＮｉ基超耐熱合金を製造する方法は、
（ａ）炭素含有量が０．０５～０．２５質量％であり、かつ７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有する材料に対して、９００℃以上の温度で塑性加工を行なった後に冷却して、第１の加工材を作製する工程と、
（ｂ）前記第１の加工材を９００℃以上の温度に加熱して熱処理を行い、第１の熱処理材を作製する工程と
を含むものである。
　そして、上記の（ａ）と（ｂ）との工程に、さらに、
（ｃ）前記第１の熱処理材を素材として、この素材に、５００℃以下の温度で塑性加工を行ない、第２の加工材を作製する工程と
を含むものである。 Therefore, according to the present invention, the method for producing a Ni-based superheat resistant alloy having a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more is
(A) A temperature of 900 ° C. or higher with respect to a material having a carbon content of 0.05 to 0.25 mass% and a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more. The process of producing the first processed material by cooling after performing plastic processing in
(B) It includes a step of heating the first processed material to a temperature of 900 ° C. or higher to perform heat treatment to prepare the first heat-treated material.
Then, in addition to the steps (a) and (b) described above,
(C) The first heat-treated material is used as a material, and this material is subjected to plastic working at a temperature of 500 ° C. or lower to produce a second processed material.
　本発明が対象とするＮｉ基超耐熱合金は、炭素含有量が０．０５～０．２５質量％であり、７００℃におけるガンマプライム（γ’）相の平衡析出量が３５モル％以上の成分組成を有する。
　ここで、Ｎｉ基超耐熱合金のγ’相の量は、そのγ’相の「体積率」や「面積率」等の数値的指標で表すことができる。本明細書では、γ’相の量を、「γ’モル率」の数値的指標で表す。γ’モル率とは、Ｎｉ基超耐熱合金が熱力学的な平衡状態において析出することができる、安定的なガンマプライム相の平衡析出量のことである。ガンマプライム相の平衡析出量を「モル率」で表した値は、Ｎｉ基超耐熱合金が有する成分組成により決定される。この平衡析出量のモル％の値は、熱力学平衡計算による解析で求めることができる。熱力学平衡計算による解析では、各種の熱力学平衡計算ソフトを用いることで、精度よく、かつ、容易に求めることができる。 The Ni-based superheat-resistant alloy targeted by the present invention is a component having a carbon content of 0.05 to 0.25% by mass and an equilibrium precipitation amount of the gamma prime (γ') phase at 700 ° C. of 35 mol% or more. Has a composition.
Here, the amount of the γ'phase of the Ni-based superheat resistant alloy can be expressed by a numerical index such as "volume fraction" or "area ratio" of the γ'phase. In the present specification, the amount of the γ'phase is represented by a numerical index of “γ'molar rate”. The γ'molar ratio is a stable equilibrium precipitation amount of the gamma prime phase in which a Ni-based superheat resistant alloy can be precipitated in a thermodynamic equilibrium state. The value of the equilibrium precipitation amount of the gamma prime phase expressed in "molar ratio" is determined by the component composition of the Ni-based superheat resistant alloy. The value of mol% of this equilibrium precipitation amount can be obtained by analysis by thermodynamic equilibrium calculation. In the analysis by thermodynamic equilibrium calculation, it can be obtained accurately and easily by using various thermodynamic equilibrium calculation software.
　本発明では、Ｎｉ基超耐熱合金のγ’モル率を、「７００℃における平衡析出量」とする。Ｎｉ基超耐熱合金の高温強度は、組織中のガンマプライム相の平衡析出量で評価でき、この高温強度が大きいほど、熱間塑性加工は困難になる。組織中のガンマプライム相の平衡析出量は、一般的に、概ね７００℃以下で温度依存性が小さくなり、概ね一定となるので、上記の「７００℃」のときの値を基準とする。 In the present invention, the γ'molar ratio of the Ni-based superheat-resistant alloy is defined as the “equilibrium precipitation amount at 700 ° C.”. The high temperature strength of the Ni-based superheat resistant alloy can be evaluated by the equilibrium precipitation amount of the gamma prime phase in the structure, and the larger the high temperature strength, the more difficult the hot plastic working. The equilibrium precipitation amount of the gamma prime phase in the structure is generally about 700 ° C. or lower, the temperature dependence becomes small and becomes almost constant, so the value at "700 ° C." is used as a reference.
　上記の通り、通常はＮｉ基超耐熱合金のγ’モル率が大きいほど熱間塑性加工は困難である。しかし、本発明によれば、γ’モル率を大きくすることが、Ｎｉ基超耐熱合金の冷間の塑性加工性の向上に大きく関与する。Ｎｉ基超耐熱合金の断面組織中に「ナノ結晶粒」を有することで、冷間塑性加工性を飛躍的に改善できる。このナノ結晶粒は、Ｎｉ基超耐熱合金のマトリックスであるオーステナイト相（ガンマ（γ）相）とガンマプライム相との相界面から最も発生しやすい。したがって、Ｎｉ基超耐熱合金のγ’モル率を大きくすることは、上記の相界面の増加に繋がって、ナノ結晶粒の生成に寄与する。図１は、本発明の製造方法において線材の冷間塑性加工により生成された断面ミクロ組織のＥＢＳＤ像の例を示したものである。ＥＢＳＤの測定条件は、走査型電子顕微鏡「ＵＬＴＲＡ５５（Ｚｅｉｓｓ社製）」に付属したＥＢＳＤ測定システム「ＯＩＭ　Ｖｅｒｓｉｏｎ　５．３．１（ＴＳＬ　Ｓｏｌｕｔｉｏｎ社製）」を使用して、倍率：１００００倍、スキャンステップ：０．０１μｍとし、結晶粒の定義は方位差１５°以上を粒界とした。図１でＥＢＳＤ像に確認されたナノ結晶粒（囲み部）の最大径（最大長さ）は、小さいもので約２５ｎｍである。 As mentioned above, hot plastic working is usually more difficult as the γ'molar ratio of the Ni-based superheat resistant alloy is larger. However, according to the present invention, increasing the γ'molar ratio greatly contributes to the improvement of the cold plastic workability of the Ni-based superheat resistant alloy. By having "nanocrystal grains" in the cross-sectional structure of the Ni-based superheat-resistant alloy, the cold plastic workability can be dramatically improved. These nanocrystal grains are most likely to be generated from the phase interface between the austenite phase (gamma (γ) phase), which is a matrix of Ni-based superheat-resistant alloys, and the gamma prime phase. Therefore, increasing the γ'molar ratio of the Ni-based superheat-resistant alloy leads to an increase in the above-mentioned phase interface and contributes to the formation of nanocrystal grains. FIG. 1 shows an example of an EBSD image of a cross-sectional microstructure produced by cold plastic working of a wire rod in the manufacturing method of the present invention. The EBSD measurement conditions are as follows: Using the EBSD measurement system "OIM Version 5.3.1 (manufactured by TSL Solution)" attached to the scanning electron microscope "ULTRA55 (manufactured by Zeiss)", magnification: 10000 times, scanning Step: 0.01 μm, and the definition of crystal grains was defined as grain boundaries with an orientation difference of 15 ° or more. The maximum diameter (maximum length) of the nanocrystal grains (enclosed portion) confirmed in the EBSD image in FIG. 1 is as small as about 25 nm.
　γ’モル率が３５％のレベルにまで達すると、上記のナノ結晶粒の生成が促進される。７００℃におけるガンマプライム相の平衡析出量が４０モル％以上の成分組成がより好ましい。更に好ましいガンマプライム相の平衡析出量は、５０モル％以上であり、更により好ましくは６０モル％以上である。特に好ましいガンマプライム相の平衡析出量は６３モル％以上であり、いっそう好ましくは６６モル％以上、よりいっそう好ましくは６８モル％以上である。７００℃におけるガンマプライム相の平衡析出量の上限は、特に限定しないが、７５モル％程度が現実的である。 When the γ'mol ratio reaches the level of 35%, the formation of the above-mentioned nanocrystal grains is promoted. A component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 40 mol% or more is more preferable. The equilibrium precipitation amount of the gamma prime phase is more preferably 50 mol% or more, and even more preferably 60 mol% or more. A particularly preferable equilibrium precipitation amount of the gamma prime phase is 63 mol% or more, more preferably 66 mol% or more, and even more preferably 68 mol% or more. The upper limit of the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is not particularly limited, but is practically about 75 mol%.
　７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の析出強化型のＮｉ基超耐熱合金として、例えば、質量％で、Ｃ：０．０５～０．２５％、Ｃｒ：８．０～２５．０％、Ａｌ：０．５～８．０％、Ｔｉ：０．４～７．０％、Ｃｏ：０～２８．０％、Ｍｏ：０～８．０％、Ｗ：０～１５．０％、Ｎｂ：０～４．０％、Ｔａ：０～５．０％、Ｆｅ：０～１０．０％、Ｖ：０～１．２％、Ｈｆ：０～３．０％、Ｂ：０～０．３００％、Ｚｒ：０～０．３００％を含み、残部がＮｉおよび不純物からなる組成を有することが好ましい。 As a precipitation-enhanced Ni-based superheat-resistant alloy in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more, for example, in mass%, C: 0.05 to 0.25%, Cr: 8.0 to 25.0%, Al: 0.5 to 8.0%, Ti: 0.4 to 7.0%, Co: 0 to 28.0%, Mo: 0 to 8.0%, W: 0 to 15 .0%, Nb: 0 to 4.0%, Ta: 0 to 5.0%, Fe: 0 to 10.0%, V: 0 to 1.2%, Hf: 0 to 3.0%, B It is preferable that the composition contains 0 to 0.300%, Zr: 0 to 0.300%, and the balance is composed of Ni and impurities.
　以下、本発明のＮｉ基超耐熱合金の好ましい組成の各成分について説明する（成分組成の単位は「質量％」である）。 Hereinafter, each component having a preferable composition of the Ni-based superheat-resistant alloy of the present invention will be described (the unit of the component composition is "mass%").
炭素（Ｃ）
　Ｃは、従来、Ｎｉ基超耐熱合金の鋳造性を高める元素として含有するものである。そして、特に、γ’相の量の多いＮｉ基超耐熱合金は、塑性加工が困難であるため、通常、鋳造部品として使用され、一定量のＣが添加されている。この添加されたＣは、鋳造組織中に炭化物として残り、一部は粗大な共晶炭化物として形成される。そして、このような粗大な炭化物は、Ｎｉ基超耐熱合金を塑性加工したときに、特に、室温で塑性加工したときに、亀裂の起点および亀裂の進展経路となり、Ｎｉ基超耐熱合金の塑性加工性に悪影響を及ぼす。 Carbon (C)
Conventionally, C is contained as an element that enhances the castability of a Ni-based superheat resistant alloy. In particular, Ni-based superheat-resistant alloys having a large amount of γ'phase are usually used as cast parts because plastic working is difficult, and a certain amount of C is added. This added C remains as a carbide in the cast structure, and a part of it is formed as a coarse eutectic carbide. Then, such coarse carbides serve as a crack starting point and a crack growth path when the Ni-based superheat-resistant alloy is plastically processed, especially when the Ni-based superheat-resistant alloy is plastically processed at room temperature. It has an adverse effect on sexuality.
　したがって、γ’相の量の多いＮｉ基超耐熱合金を、鋳造部品としてではなく、塑性加工によりＮｉ基超耐熱合金を製造することを目的とした本発明にとって、そのＮｉ基超耐熱合金中のＣを低減することは好ましい。本発明の場合、Ｃの含有量は０．２５％以下とする。好ましくは０．２０％以下である。より好ましくは０．１５％以下である。
　しかし、Ｃは、耐熱部品の強度を高める元素でもあり、そのような耐熱部品を作製したり、補修したりすることを考えれば、Ｃを含有していることが好ましい。本発明のＮｉ基超耐熱合金の製造方法によれば、上述のナノ結晶粒の効果によって、高Ｃ含有量の合金でも塑性加工が可能になる。その場合でも、高Ｃ含有量の合金の場合、室温での塑性加工により細線や線材、その他の形状品を製造するとなると、上記の炭化物が亀裂の起点および亀裂の進展経路となり得る問題によって、加工率が制限される。これに対して、上記の塑性加工前のＮｉ基超耐熱合金を、後述する第１の熱間塑性加工と第１の熱処理とで作製した「素材」とすることによって、上記の炭化物の亀裂の問題にも対応できるので、例えば、鋳造部品における含有量と同程度のＣ含有量を許容することができる。
　よって、本発明によるＮｉ基超耐熱合金を製造方法では、Ｃは０．０５％以上含有するものとする。好ましくは０．０６％以上、より好ましくは０．０７％以上、さらに好ましくは０．１％以上とする。よりさらに、Ｃは０．１％を超えて含有していてもよい。 Therefore, for the present invention in which a Ni-based superheat-resistant alloy having a large amount of γ'phase is produced by plastic working, not as a cast part, in the Ni-based superheat-resistant alloy. It is preferable to reduce C. In the case of the present invention, the C content is 0.25% or less. It is preferably 0.20% or less. More preferably, it is 0.15% or less.
However, C is also an element that enhances the strength of heat-resistant parts, and it is preferable that C is contained in consideration of producing or repairing such heat-resistant parts. According to the method for producing a Ni-based superheat-resistant alloy of the present invention, plastic working is possible even with an alloy having a high C content due to the effect of the nanocrystal grains described above. Even in that case, in the case of alloys with a high C content, when thin wires, wire rods, and other shaped products are manufactured by plastic working at room temperature, the above carbides can serve as crack origins and crack growth paths. The rate is limited. On the other hand, by using the Ni-based superheat-resistant alloy before plastic working as a "material" produced by the first hot plastic working and the first heat treatment described later, the above-mentioned carbide cracks can be cracked. Since the problem can be dealt with, for example, a C content similar to that in a cast part can be tolerated.
Therefore, in the method for producing a Ni-based superheat-resistant alloy according to the present invention, C is assumed to be contained in an amount of 0.05% or more. It is preferably 0.06% or more, more preferably 0.07% or more, still more preferably 0.1% or more. Furthermore, C may be contained in an amount of more than 0.1%.
クロム（Ｃｒ）
　Ｃｒは、耐酸化性、耐食性を向上させる元素である。しかし、Ｃｒを過剰に含有すると、σ（シグマ）相などの脆化相を形成し、強度や素材準備の際の熱間加工性を低下させる。したがって、Ｃｒは、例えば、８．０～２５．０％とすることが好ましい。より好ましくは８．０～２２．０％である。好ましい下限は９．０％であり、より好ましくは９．５％である。さらに好ましくは１０．０％である。また、好ましい上限は１８．０％であり、より好ましくは１６．０％である。さらに好ましくは１４．０％である。特に好ましくは１２．５％である。 Chromium (Cr)
Cr is an element that improves oxidation resistance and corrosion resistance. However, if Cr is excessively contained, an embrittled phase such as a σ (sigma) phase is formed, which reduces the strength and hot workability at the time of material preparation. Therefore, Cr is preferably set to, for example, 8.0 to 25.0%. More preferably, it is 8.0 to 22.0%. The preferred lower limit is 9.0%, more preferably 9.5%. More preferably, it is 10.0%. The upper limit is preferably 18.0%, more preferably 16.0%. More preferably, it is 14.0%. Particularly preferably, it is 12.5%.
モリブデン（Ｍｏ）
　Ｍｏは、マトリックスの固溶強化に寄与し、高温強度を向上させる効果がある。しかし、Ｍｏが過剰になると金属間化合物相が形成されて高温強度を損なう。よって、Ｍｏは、０～８．０％とすることが好ましい（無添加（不可避不純物レベル）でもよい）。より好ましくは、２．０～７．０％である。さらに好ましい下限は２．５％であり、より好ましくは３．０％である。さらに好ましくは３．５％である。また、さらに好ましい上限は６．０％であり、より好ましくは５．０％である。 Molybdenum (Mo)
Mo contributes to the solid solution strengthening of the matrix and has the effect of improving the high temperature strength. However, when Mo becomes excessive, an intermetallic compound phase is formed and the high temperature strength is impaired. Therefore, Mo is preferably 0 to 8.0% (addition-free (unavoidable impurity level) may be used). More preferably, it is 2.0 to 7.0%. A further preferred lower limit is 2.5%, more preferably 3.0%. More preferably, it is 3.5%. Further, the upper limit is more preferably 6.0%, more preferably 5.0%.
アルミニウム（Ａｌ）
　Ａｌは、強化相であるγ’（Ｎｉ３Ａｌ）相を形成し、高温強度を向上させる元素である。しかし、過度の添加は素材準備の際の熱間加工性を低下させ、加工中の割れなどの材料欠陥の原因となる。よって、Ａｌは、０．５～８．０％が好ましい。より好ましくは２．０～８．０％である。さらに好ましい下限は２．５％であり、より好ましくは３．０％である。さらに好ましくは４．０％であり、よりさらに好ましくは４．５％である。特に好ましくは５．１％である。また、さらに好ましい上限は７．５％であり、より好ましくは７．０％である。さらに好ましくは６．５％である。
　なお、上述したＣｒとの関係で、素材準備の際の熱間加工性を確保するために、Ｃｒの含有量を低減したときには、その低減分のＡｌの含有量を許容することができる。そして、例えば、Ｃｒの上限を１３．５％にしたときに、Ａｌの含有量の下限を３．５％とすることが好ましい。 Aluminum (Al)
Al is an element that forms a γ'(Ni 3 Al) phase, which is a strengthening phase, and improves high-temperature strength. However, excessive addition reduces hot workability during material preparation and causes material defects such as cracks during processing. Therefore, Al is preferably 0.5 to 8.0%. More preferably, it is 2.0 to 8.0%. A further preferred lower limit is 2.5%, more preferably 3.0%. It is even more preferably 4.0% and even more preferably 4.5%. Particularly preferably, it is 5.1%. Further, the upper limit is more preferably 7.5%, and more preferably 7.0%. More preferably, it is 6.5%.
In relation to the above-mentioned Cr, when the Cr content is reduced in order to ensure hot workability at the time of material preparation, the reduced Al content can be allowed. Then, for example, when the upper limit of Cr is set to 13.5%, the lower limit of the Al content is preferably set to 3.5%.
チタン（Ｔｉ）
　Ｔｉは、Ａｌと同様、γ’相を形成し、γ’相を固溶強化して高温強度を高める元素である。しかし、過度の添加は、γ’相が高温で不安定となって高温での粗大化を招くとともに、有害なη（イータ）相を形成し、素材準備の際の熱間加工性を損なう。よって、Ｔｉは、例えば、０．４～７．０％が好ましい。他のγ’生成元素やＮｉマトリックスとのバランスを考慮すると、Ｔｉの好ましい下限は０．６％であり、より好ましくは０．７％である。さらに好ましくは０．８％である。また、好ましい上限は６．５％であり、より好ましくは６．０％である。さらに好ましくは４．０％であり、特に好ましくは２．０％である。 Titanium (Ti)
Like Al, Ti is an element that forms a γ'phase and strengthens the γ'phase by solid solution to increase high-temperature strength. However, excessive addition causes the γ'phase to become unstable at high temperatures, leading to coarsening at high temperatures, forming a harmful η (eta) phase, and impairing hot workability during material preparation. Therefore, Ti is preferably 0.4 to 7.0%, for example. Considering the balance with other γ'forming elements and Ni matrix, the preferable lower limit of Ti is 0.6%, more preferably 0.7%. More preferably, it is 0.8%. The upper limit is preferably 6.5%, more preferably 6.0%. It is more preferably 4.0%, and particularly preferably 2.0%.
　以下、本発明のＮｉ基超耐熱合金に添加可能な任意成分について説明する。 Hereinafter, optional components that can be added to the Ni-based superheat-resistant alloy of the present invention will be described.
コバルト（Ｃｏ）
　Ｃｏは、組織の安定性を改善し、強化元素であるＴｉを多く含有しても素材準備の際の熱間加工性を維持することを可能とする。一方で、Ｃｏは高価なものであるため、コストが上昇する。よって、Ｃｏは、他元素との組み合わせにより、例えば、２８．０％以下の範囲で含有することができる任意元素の一つである。Ｃｏを添加する場合の好ましい下限は８．０％とすると良い。より好ましくは１０．０％である。また、Ｃｏの好ましい上限は１８．０％とする。より好ましくは１６．０％である。なお、γ’生成元素やＮｉマトリックスとのバランスにより、Ｃｏを無添加レベル（原料の不可避不純物レベル）としても良い場合は、Ｃｏの下限を０％とする。 Cobalt (Co)
Co improves the stability of the structure and makes it possible to maintain the hot workability at the time of material preparation even if a large amount of Ti, which is a reinforcing element, is contained. On the other hand, since Co is expensive, the cost increases. Therefore, Co is one of the arbitrary elements that can be contained in the range of 28.0% or less, for example, by combining with other elements. The preferable lower limit when adding Co is preferably 8.0%. More preferably, it is 10.0%. The preferable upper limit of Co is 18.0%. More preferably, it is 16.0%. If Co may be added-free (the level of unavoidable impurities in the raw material) depending on the balance with the γ'forming element and the Ni matrix, the lower limit of Co is set to 0%.
タングステン（Ｗ）
　Ｗは、Ｍｏと同様、マトリックスの固溶強化に寄与する選択元素の一つである。しかし、Ｗが過剰となると有害な金属間化合物相が形成されて高温強度を損なうため、例えば、上限を１５．０％とする。好ましい上限は１３．０％であり、より好ましくは１１．０％であり、さらに好ましくは９．０％である。上記のＷの効果をより確実に発揮させるには、Ｗの下限を１．０％とすると良い。好ましくは、Ｗの下限を、３．０％、５．０％、７．０％にすることもできる。また、ＷとＭｏとを複合添加することにより、より固溶強化効果が発揮できる。複合添加の場合のＷは０．８％以上の添加が好ましい。なお、Ｍｏの十分な添加により、Ｗを無添加レベル（原料の不可避不純物レベル）としても良い場合は、Ｗの下限を０％とする。 Tungsten (W)
Like Mo, W is one of the selective elements that contributes to the solid solution strengthening of the matrix. However, if W is excessive, a harmful intermetallic compound phase is formed and the high temperature strength is impaired. Therefore, for example, the upper limit is set to 15.0%. The preferred upper limit is 13.0%, more preferably 11.0%, and even more preferably 9.0%. In order to more reliably exert the effect of W described above, the lower limit of W is preferably 1.0%. Preferably, the lower limit of W can be set to 3.0%, 5.0%, 7.0%. Further, by adding W and Mo in combination, a more solid solution strengthening effect can be exhibited. In the case of composite addition, W is preferably added in an amount of 0.8% or more. If W can be set to a non-addition level (a level of unavoidable impurities in the raw material) by sufficiently adding Mo, the lower limit of W is set to 0%.
ニオブ（Ｎｂ）
　Ｎｂは、ＡｌやＴｉと同様、γ’相を形成し、γ’相を固溶強化して高温強度を高める選択元素の一つである。しかし、Ｎｂの過度の添加は有害なδ（デルタ）相を形成し、素材準備の際の熱間加工性を損なう。よって、Ｎｂの上限は、例えば、４．０％とする。好ましい上限は３．５％であり、より好ましくは２．５％である。なお、上記のＮｂの効果をより確実に発揮させるには、Ｎｂの下限を１．０％とすると良い。好ましくは２．０％とすると良い。他のγ’生成元素の添加により、Ｎｂを無添加レベル（不可避不純物レベル）としてもよい場合は、Ｎｂの下限を０％とする。 Niobium (Nb)
Like Al and Ti, Nb is one of the selective elements that forms the γ'phase and strengthens the γ'phase by solid solution to increase the high temperature strength. However, excessive addition of Nb forms a harmful delta phase, impairing hot workability during material preparation. Therefore, the upper limit of Nb is, for example, 4.0%. The preferred upper limit is 3.5%, more preferably 2.5%. In order to more reliably exert the effect of Nb, the lower limit of Nb is preferably 1.0%. It is preferably 2.0%. When Nb may be set to a non-addition level (unavoidable impurity level) by adding another γ'forming element, the lower limit of Nb is set to 0%.
タンタル（Ｔａ）
　Ｔａは、ＡｌやＴｉと同様、γ’相を形成し、γ’相を固溶強化して高温強度を高める選択元素の一つである。ただし、Ｔａの過度の添加は、γ’相が高温で不安定となって高温での粗大化を招くとともに、有害なη（イータ）相を形成し、素材準備の際の熱間加工性を損なう。よって、Ｔａは、例えば、５．０％以下とする。好ましくは４．０％以下、より好ましくは３．０％以下、さらに好ましくは２．５％以下である。なお、上記のＴａの効果をより確実に発揮させるには、Ｔａの下限を０．３％とすると良い。好ましくは、Ｔａの下限を、０．８％、１．５％、２．０％にすることもできる。ＴｉやＮｂなどのγ’生成元素添加やマトリックスとのバランスにより、Ｔａを無添加レベル（不可避不純物レベル）としても良い場合は、Ｔａの下限を０％とする。 Tantalum (Ta)
Like Al and Ti, Ta is one of the selective elements that forms the γ'phase and strengthens the γ'phase by solid solution to increase the high temperature strength. However, excessive addition of Ta causes the γ'phase to become unstable at high temperatures, leading to coarsening at high temperatures and forming a harmful η (eta) phase, which improves hot workability during material preparation. To spoil. Therefore, Ta is set to 5.0% or less, for example. It is preferably 4.0% or less, more preferably 3.0% or less, still more preferably 2.5% or less. In order to more reliably exert the effect of Ta, the lower limit of Ta is preferably 0.3%. Preferably, the lower limit of Ta can be 0.8%, 1.5%, 2.0%. If Ta may be an additive-free level (unavoidable impurity level) due to the addition of γ'forming elements such as Ti and Nb and the balance with the matrix, the lower limit of Ta is set to 0%.
鉄（Ｆｅ）
　Ｆｅは、高価なＮｉ、Ｃｏの代替として用いる選択元素の一つであり、合金コストの低減に有効である。この効果を得るには、他元素との組み合わせで添加するかどうかを決定すると良い。ただし、Ｆｅを過剰に含有するとσ（シグマ）相などの脆化相を形成し、強度や素材準備の際の熱間加工性を低下させる。よって、Ｆｅの上限は、例えば、１０．０％とする。好ましい上限は９．０％であり、より好ましくは８．０％である。一方、γ’生成元素やＮｉマトリックスとのバランスにより、Ｆｅを無添加レベル（不可避不純物レベル）としてもよい場合は、Ｆｅの下限を０％とする。 Iron (Fe)
Fe is one of the selective elements used as a substitute for expensive Ni and Co, and is effective in reducing the alloy cost. To obtain this effect, it is advisable to decide whether or not to add in combination with other elements. However, if Fe is excessively contained, an embrittled phase such as a σ (sigma) phase is formed, which reduces the strength and hot workability at the time of material preparation. Therefore, the upper limit of Fe is, for example, 10.0%. The preferred upper limit is 9.0%, more preferably 8.0%. On the other hand, when Fe may be added-free level (unavoidable impurity level) depending on the balance with the γ'forming element and Ni matrix, the lower limit of Fe is set to 0%.
バナジウム（Ｖ）
　Ｖは、マトリックスの固溶強化、炭化物生成による粒界強化に有用な選択元素の一つである。ただし、Ｖの過度の添加は製造過程の高温不安定相の生成を招き、製造性および高温力学性能に悪影響を招く。よって、Ｖの上限は、例えば、１．２％とする。好ましい上限は１．０％であり、より好ましくは０．８％である。なお、上記のＶの効果をより確実に発揮させるには、Ｖの下限を０．５％とすると良い。合金中の他合金元素とのバランスにより、Ｖを無添加レベル（不可避不純物レベル）としても良い場合は、Ｖの下限を０％とする。 Vanadium (V)
V is one of the selective elements useful for strengthening the solid solution of the matrix and strengthening the grain boundaries by forming carbides. However, excessive addition of V leads to the formation of a high temperature unstable phase in the manufacturing process, which adversely affects the manufacturability and the high temperature mechanical performance. Therefore, the upper limit of V is, for example, 1.2%. The preferred upper limit is 1.0%, more preferably 0.8%. In order to more reliably exert the effect of V, the lower limit of V is preferably 0.5%. If V may be an additive-free level (unavoidable impurity level) due to the balance with other alloying elements in the alloy, the lower limit of V is set to 0%.
ハフニウム（Ｈｆ）
　Ｈｆは、合金の耐酸化性向上、炭化物生成による粒界強化に有用な選択元素の一つである。ただし、Ｈｆの過度の添加は、製造過程の酸化物生成、高温不安定相の生成を招き、製造性および高温力学性能に悪影響を招く。よって、Ｈｆの上限は、例えば、３．０％、好ましくは２．０％、より好ましくは１．５％とする。なお、上記のＨｆの効果をより確実に発揮させるには、Ｈｆの下限を０．１％とすると良い。好ましくは、Ｈｆの下限を、０．５％、０．７％、１．０％にすることもできる。合金中の他合金元素とのバランスにより、Ｈｆを無添加レベル（不可避不純物レベル）としても良い場合は、Ｈｆの下限を０％とする。 Hafnium (Hf)
Hf is one of the selective elements useful for improving the oxidation resistance of alloys and strengthening grain boundaries by forming carbides. However, excessive addition of Hf causes oxide formation in the manufacturing process and formation of a high temperature unstable phase, which adversely affects manufacturability and high temperature mechanical performance. Therefore, the upper limit of Hf is, for example, 3.0%, preferably 2.0%, and more preferably 1.5%. In order to more reliably exert the above-mentioned effect of Hf, the lower limit of Hf may be set to 0.1%. Preferably, the lower limit of Hf can be 0.5%, 0.7%, 1.0%. When Hf may be added-free level (unavoidable impurity level) depending on the balance with other alloying elements in the alloy, the lower limit of Hf is set to 0%.
ホウ素（Ｂ）
　Ｂは、粒界強度を向上させ、クリープ強度、延性を改善する元素である。一方で、Ｂは融点を低下させる効果が大きいこと、また、粗大なホウ化物が形成されると素材準備の際の熱間加工性が阻害されることから、例えば、０．３００％を超えないように制御すると良い。好ましい上限は０．２００％であり、より好ましくは０．１００％である。さらに好ましくは０．０５０％であり、特に好ましくは０．０２０％である。なお、上記の効果を得るには最低０．００１％の含有が好ましい。より好ましい下限は０．００３％であり、さらに好ましくは０．００５％である。特に好ましくは０．０１０％である。合金中の他合金元素とのバランスにより、Ｂを無添加レベル（不可避不純物レベル）としても良い場合は、Ｂの下限を０％とする。 Boron (B)
B is an element that improves grain boundary strength and improves creep strength and ductility. On the other hand, B has a large effect of lowering the melting point, and when a coarse boride is formed, the hot workability at the time of material preparation is hindered. Therefore, for example, it does not exceed 0.300%. It is good to control it like this. The preferred upper limit is 0.200%, more preferably 0.100%. It is more preferably 0.050%, and particularly preferably 0.020%. In order to obtain the above effect, the content is preferably at least 0.001%. A more preferable lower limit is 0.003%, and even more preferably 0.005%. Particularly preferably, it is 0.010%. If B may be added-free level (unavoidable impurity level) depending on the balance with other alloying elements in the alloy, the lower limit of B is set to 0%.
ジルコニウム（Ｚｒ）
　Ｚｒは、Ｂと同様、粒界強度を向上させる効果を有している。一方で、Ｚｒが過剰となると、やはり融点の低下を招き、高温強度や素材準備の際の熱間加工性が阻害される。よって、Ｚｒの上限は、例えば、０．３００％とする。好ましい上限は０．２５０％であり、より好ましくは０．２００％である。さらに好ましくは０．１００％であり、特に好ましくは０．０５０％である。なお、上記の効果を得るには最低０．００１％の含有が好ましい。より好ましい下限は０．００５％であり、さらに好ましくは０．０１０％である。合金中の他合金元素とのバランスにより、Ｚｒを無添加レベル（不可避不純物レベル）としても良い場合は、Ｚｒの下限を０％とする。 Zirconium (Zr)
Like B, Zr has the effect of improving the grain boundary strength. On the other hand, if Zr is excessive, the melting point is also lowered, and the high temperature strength and the hot workability at the time of material preparation are impaired. Therefore, the upper limit of Zr is, for example, 0.300%. The preferred upper limit is 0.250%, more preferably 0.200%. It is more preferably 0.100%, and particularly preferably 0.050%. In order to obtain the above effect, the content is preferably at least 0.001%. A more preferable lower limit is 0.005%, and even more preferably 0.010%. When Zr may be added-free level (unavoidable impurity level) depending on the balance with other alloying elements in the alloy, the lower limit of Zr is set to 0%.
　以上に説明した元素以外の残部はＮｉであるが、不可避不純物を含んでもよい。 The balance other than the elements described above is Ni, but it may contain unavoidable impurities.
　次に、上記に説明した成分組成を有するＮｉ基超耐熱合金を製造する本発明の製造方法や、Ｎｉ基超耐熱合金について、一具体例を説明する。 Next, a specific example of the production method of the present invention for producing a Ni-based superheat-resistant alloy having the component composition described above and the Ni-based superheat-resistant alloy will be described.
（ａ）第１の加工材を作製する工程
　後述の熱処理に供する第１の加工材の作製方法は特に限定されない。例えば、第１の加工材は、溶湯を鋳型に注湯して鋳塊を作製する溶製法によって得ることができる。そして、鋳塊の製造には、例えば、真空溶解と、真空アーク再溶解やエレクトロスラグ再溶解等の常法を、組み合わせる等して適用してもよい。あるいは、第１の加工材は、粉末冶金法によって得られたものであってもよい。そして、上記の鋳塊や、粉末冶金法で作製された合金塊の材料に対して、熱間鍛造、熱間圧延、熱間押出などの熱間加工を施した後に冷却して、所定の形状の加工材に仕上げることができる。例えば、棒材（ｂａｒ　ｍａｔｅｒｉａｌ）の形状の加工材に仕上げてもよい。熱間加工における加工温度（加工開始温度）は９００℃以上とする。また、塑性加工を容易にするために、好ましくは９５０℃以上、より好ましくは１０００℃以上、さらに好ましくは１０５０℃以上である。そして、高くても１２５０℃以下が現実的である。
　また、これら作業の間で、均熱処理（ソーキング）等の熱処理を施すことができる。たとえば、鋳塊の元素偏析を解消するためにソーキング（例えば１１００℃～１２８０℃で５～６０時間保持）を行なってもよい。あるいは、例えば、熱間押出に供する材料（ビレット（ｂｉｌｌｅｔ））の形状に仕上げてからソーキングを行なってもよい。
　冷却後の加工材は、必要に応じて、機械加工（例えば、寸法調整や各種手入れのための切断や研磨、研削など）を施すことができる。 (A) Step of Producing First Processed Material The method of producing the first processed material to be subjected to the heat treatment described later is not particularly limited. For example, the first processed material can be obtained by a melting method in which molten metal is poured into a mold to produce an ingot. Then, for the production of the ingot, for example, vacuum melting may be applied by combining conventional methods such as vacuum arc remelting and electroslag remelting. Alternatively, the first processed material may be obtained by a powder metallurgy method. Then, the above-mentioned ingot or alloy ingot material produced by the powder metallurgy method is subjected to hot working such as hot forging, hot rolling, and hot extrusion, and then cooled to form a predetermined shape. Can be finished as a processed material. For example, it may be finished as a processed material in the shape of a bar material. The processing temperature (processing start temperature) in hot processing shall be 900 ° C. or higher. Further, in order to facilitate plastic working, the temperature is preferably 950 ° C. or higher, more preferably 1000 ° C. or higher, and even more preferably 1050 ° C. or higher. And it is realistic that the temperature is 1250 ° C or lower at the highest.
In addition, heat treatment such as soaking can be performed between these operations. For example, soaking (for example, holding at 1100 ° C. to 1280 ° C. for 5 to 60 hours) may be performed to eliminate the elemental segregation of the ingot. Alternatively, for example, soaking may be performed after finishing the shape of a material (billet) to be subjected to hot extrusion.
The processed material after cooling can be machined (for example, cutting, polishing, grinding, etc. for dimensional adjustment and various maintenance), if necessary.
　第１の加工材を作製する一例として、上記の材料に対して、熱間で押出成形を行ない、所定の形状の棒材（ｂａｒ　ｍａｔｅｒｉａｌ）の素材に仕上げる場合について説明する。熱間押出の条件は、押出温度（材料の加熱温度）１０５０℃～１２００℃、押出比４～２０、押出速度（ステム速度）５～８０ｍｍ／ｓで行なうことが好ましく、成形された押出材（ｅｘｔｒｕｄｅｄ　ｍａｔｅｒｉａｌ）の断面径は、例えば、１０ｍｍ以上や、２０ｍｍ超である。そして、例えば、２００ｍｍ以下である。そして、棒材を製造する場合、上記の押出材の表面を機械加工等によって仕上げたり、上記の押出材から所定の寸法の棒材を採取したりして、作製することができる。この場合、棒材の断面径を、例えば、１５０ｍｍ以下、１００ｍｍ以下、５０ｍｍ以下、３０ｍｍ以下、１０ｍｍ以下といった寸法にすることもできる。棒材の断面径を小さくしておくことは、後述する冷間塑性加工で、断面径がさらに小さい線材や細線等を作製するときに、その塑性加工の回数（パス数）を少なくできる点で好ましい。 As an example of producing the first processed material, a case where the above material is hotly extruded to be finished as a material of a bar material having a predetermined shape will be described. The conditions for hot extrusion are preferably an extrusion temperature (heating temperature of the material) of 1050 ° C. to 1200 ° C., an extrusion ratio of 4 to 20, and an extrusion speed (stem speed) of 5 to 80 mm / s. The cross-sectional diameter of the extruded material) is, for example, 10 mm or more or more than 20 mm. And, for example, it is 200 mm or less. Then, when the bar material is manufactured, the surface of the extruded material can be finished by machining or the like, or the bar material having a predetermined size can be collected from the extruded material. In this case, the cross-sectional diameter of the bar may be, for example, 150 mm or less, 100 mm or less, 50 mm or less, 30 mm or less, 10 mm or less. Keeping the cross-sectional diameter of the bar small is that the number of plastic workings (number of passes) can be reduced when making wire rods or thin wires with a smaller cross-sectional diameter by cold plastic working, which will be described later. preferable.
（ｂ）第１の熱処理材（素材）を作製する工程
　本発明では、まず、上記に説明した成分組成を有する第１の熱処理材（「素材」と言う。）を準備する。そして、後述する（ｃ）の塑性加工で、この素材に強加工（例えば、加工率が３０％以上の加工）を行なったＮｉ基超耐熱合金は、更に続けて加工を行なうことが可能な状態になる。したがって、塑性加工中に熱処理を行わないで、さらに大きな加工率まで冷間加工を行なうことができる。
　しかし、本発明が対象とするＮｉ基超耐熱合金は、炭素を０．０５～０．２５質量％含有する。この成分組成の材料に熱間鍛造、熱間圧延、熱間押出などの熱間加工を施して作製した素材の組織には、ＭＣやＭ２３Ｃ６に代表される各種の炭化物が形成されている。そして、素材１の組織中に粗大な炭化物２が析出している（図２）。素材１に冷間塑性加工を行なって、累積加工率が、例えば、４０％以上の冷間塑性加工を施した後のＮｉ基超耐熱合金の加工材３は、γ相とγ’相とが延伸方向に延びた線状組織になる。炭化物は、塑性加工により粉砕され微細炭化物４となるものの微細炭化物が組織の延伸方向に連なった炭化物集合体として加工組織に存在する。この微細炭化物同士の間には、材料欠陥５(例えば材料の欠落による隙間など)が形成される。このまま、更に塑性加工を行なうと、各微細炭化物４間の欠陥５が広がり、隣接する欠陥５と結合し、割れの起点となる虞がある。そこで、上記の冷間塑性加工を行なう前の段階で、組織中の炭化物の形態を調整することにより、冷間塑性加工で欠陥５が発生することを抑制できる。例えば、延伸方向の断面組織において、欠陥率を０．５面積％以下にできる。したがって、材料欠陥を起点とした割れの発生を抑制することができる。 (B) Step of Producing First Heat Treatment Material (Material) In the present invention, first, a first heat treatment material (referred to as “material”) having the component composition described above is prepared. Then, the Ni-based superheat-resistant alloy obtained by subjecting this material to strong processing (for example, processing having a processing rate of 30% or more) in the plastic working of (c) described later can be further processed. become. Therefore, cold working can be performed up to a larger working rate without performing heat treatment during plastic working.
However, the Ni-based superheat-resistant alloy targeted by the present invention contains 0.05 to 0.25% by mass of carbon. Various carbides typified by MC and M 23 C 6 are formed in the structure of the material produced by subjecting the material having this composition to hot working such as hot forging, hot rolling, and hot extrusion. There is. Then, coarse carbide 2 is precipitated in the structure of the material 1 (FIG. 2). The processed material 3 of the Ni-based superheat-resistant alloy after the material 1 is subjected to cold plastic working and the cumulative working rate is, for example, 40% or more, has a γ phase and a γ'phase. It becomes a linear structure extending in the stretching direction. The carbides are crushed by plastic working to become fine carbides 4, but the fine carbides are present in the processed structure as a carbide aggregate in which the fine carbides are connected in the extending direction of the structure. Material defects 5 (for example, gaps due to lack of material) are formed between the fine carbides. If plastic working is further performed as it is, the defects 5 between the fine carbides 4 may spread and combine with the adjacent defects 5 to become the starting point of cracking. Therefore, by adjusting the morphology of the carbides in the structure before the cold plastic working is performed, it is possible to suppress the occurrence of defects 5 in the cold plastic working. For example, in the cross-sectional structure in the stretching direction, the defect rate can be 0.5 area% or less. Therefore, it is possible to suppress the occurrence of cracks starting from material defects.
　そして、上記の炭化物の形態の調整は、上記の熱間加工を施した後に、一旦冷却された素材（「第１の加工材」と言う。）に対して、これを改めて９００℃以上の温度に加熱して熱処理を行い、第１の熱処理材を得るものである。この熱処理によって、素材組織中の炭化物の形態が調整され、塑性加工中に割れの発生が抑制される理由は、図３に示す「冷間塑性加工前の第１の加工材（押出材）に施した熱処理の温度と、冷間塑性加工性（減面率）との関係」を用いて、以下のように考えられる。 Then, in the adjustment of the form of the carbide, the temperature of the material (referred to as "first processed material") that has been once cooled after the hot working is applied to 900 ° C. or higher. The first heat-treated material is obtained by heating and heat-treating the material. The reason why the morphology of the charcoal in the material structure is adjusted by this heat treatment and the occurrence of cracks during the plastic working is suppressed is that the first processed material (extruded material) before the cold plastic working is shown in FIG. Using the relationship between the temperature of the heat treatment applied and the cold plastic workability (surface reduction rate), it can be considered as follows.
＜ステージ１＞
　上記の加工温度で熱間加工して作製された第１の加工材の組織には、粗大なＭＣが形成される。そして、このＭＣとＭ２３Ｃ６とが接してなる“複合的な炭化物”が形成される。このような組織に塑性加工を行うと、Ｍ２３Ｃ６とＭＣとが、その界面で別れて、材料欠陥が発生する要因になると考えられる。そこで、第１の加工材を９００℃以上の熱処理温度に加熱することで、ＭＣの多くがガンマ相と反応してＭ２３Ｃ６に形態変化して、特に、その表層の位置で、上記の複合的な炭化物の割合が減少する。このことによって、割れの起点となる第１の加工材の表層付近で上記の炭化物に起因する割れの発生が抑制されて、第１の熱処理材の基本的な塑性加工性が向上する。 <Stage 1>
Coarse MC is formed in the structure of the first processed material produced by hot processing at the above processing temperature. Then, a "composite carbide" formed by contacting the MC and the M 23 C 6 is formed. When plastic working is performed on such a structure, it is considered that M 23 C 6 and MC are separated at the interface and cause material defects. Therefore, by heating the first processed material to a heat treatment temperature of 900 ° C. or higher, most of the MC reacts with the gamma phase and changes its form to M 23 C 6 , especially at the position of the surface layer described above. The proportion of complex carbides is reduced. As a result, the occurrence of cracks due to the above-mentioned carbides is suppressed in the vicinity of the surface layer of the first processed material, which is the starting point of cracks, and the basic plastic workability of the first heat-treated material is improved.
＜ステージ２＞
　第１の加工材を９００℃以上の熱処理温度に加熱することで、上記の複合的な炭化物の割合が減少するものの、熱処理温度が１０００℃を超えた辺りから、Ｍ２３Ｃ６の固溶が進み始めるようである。しかしながら、Ｍ２３Ｃ６の一部はガンマプライム相と反応してＭＣに形態変化して、この結果、熱処理後の「第１の熱処理材」の組織では、形態変化したＭＣがＭ２３Ｃ６と接してなる“複合的な”炭化物が再び形成される。そして、このような組織の第１の熱処理材に塑性加工を行うと、上述した第１の加工材のように、上記の複合的な炭化物がそのＭＣとＭ２３Ｃ６との界面で別れて、上記の材料欠陥が発生する要因になっていると考えられる。この結果、塑性加工中の素材は、特に、その内部において炭化物に起因する割れが生じやすく、塑性加工性がステージ１のものから低下する傾向となる。しかし、このような傾向であるにも係わらず、熱処理後の第１の熱処理材の結晶粒径は第１の加工材のものから成長して、第１の熱処理材の塑性加工性は第１の加工材のものより優れ得る。 <Stage 2>
By heating the first processed material to a heat treatment temperature of 900 ° C. or higher, the proportion of the above-mentioned composite carbides decreases, but when the heat treatment temperature exceeds 1000 ° C., the solid solution of M 23 C 6 is formed. It seems to start moving forward. However, a part of M 23 C 6 reacts with the gamma prime phase to change its morphology to MC, and as a result, in the structure of the "first heat treatment material" after the heat treatment, the morphologically changed MC is changed to M 23 C 6 The "composite" carbides that come into contact with are formed again. Then, when the first heat-treated material having such a structure is subjected to plastic working, the above-mentioned composite carbide is separated at the interface between the MC and M 23 C 6 like the above-mentioned first processed material. , It is considered that it is a factor that causes the above-mentioned material defects. As a result, the material being plastically worked tends to be cracked due to carbides, and the plastic workability tends to be lower than that of the stage 1 material. However, in spite of this tendency, the crystal grain size of the first heat-treated material after the heat treatment grows from that of the first processed material, and the plastic workability of the first heat-treated material is the first. Can be superior to that of processed materials.
＜ステージ３＞
　熱処理温度が１０００℃の辺りを超えることで、上記の通り、熱処理後の第１の熱処理材の塑性加工性は低下する傾向にあるものの、熱処理温度が１１５０℃を超えた辺りから、第１の熱処理材の塑性加工性は向上に大きく転じる。これは、Ｍ２３Ｃ６のＭＣへの形態変化が進むところ、これ以上に、Ｍ２３Ｃ６の固溶が進むことによる。そして、熱処理温度が１２００℃にも達すると、組織中のＭ２３Ｃ６は殆どが固溶して、組織中にＭＣが残留するとしても、上述した“複合的な”炭化物の量は大きく減少する。そして、このことに、結晶粒の著しい成長も作用して、第１の熱処理材の塑性加工性は大きく向上する。 <Stage 3>
As described above, when the heat treatment temperature exceeds about 1000 ° C., the plastic workability of the first heat treatment material after the heat treatment tends to decrease, but when the heat treatment temperature exceeds 1150 ° C., the first heat treatment material becomes the first. The plastic workability of the heat-treated material is greatly improved. This is because the morphological change of M 23 C 6 to MC progresses, and the solid solution of M 23 C 6 further progresses. Then, when the heat treatment temperature reaches 1200 ° C., most of M 23 C 6 in the structure is solid-solved, and even if MC remains in the structure, the amount of the above-mentioned "composite" carbide is greatly reduced. To do. Then, the remarkable growth of the crystal grains also acts on this, and the plastic workability of the first heat-treated material is greatly improved.
　以上の結果をして、本発明に係る第１の熱処理材は、その断面組織において、Ｍ２３Ｃ６の面積率が、例えば、４．０面積％以下や、３．０面積％以下、２．０面積％以下のものである。好ましくは、例えば、１．５面積％以下や、１．０面積％以下、０．７面積％以下、０．５面積％以下である。そして、さらに好ましくは、０．３面積％以下や、０．２面積％以下、０．１面積％以下である（０面積％の場合を含む）。
　また、本発明に係る第１の熱処理材は、好ましくは、その断面組織において、Ｍ２３Ｃ６の個数密度が、例えば、１０．０×１０－２個／μｍ２以下や、７．０×１０－２個／μｍ２以下、５．０×１０－２個／μｍ２以下、３．０×１０－２個／μｍ２以下のものである。また、Ｍ２３Ｃ６の固溶が進むに連れて、より好ましくは、例えば、１．５×１０－２個／μｍ２以下や、１．３×１０－２個／μｍ２以下、１．０×１０－２個／μｍ２以下、０．５×１０－２個／μｍ２以下である。そして、さらに好ましくは、例えば、０．３×１０－２個／μｍ２以下や、０．２×１０－２個／μｍ２以下、０．１×１０－２個／μｍ２以下である（０個／μｍ２の場合を含む）。 Based on the above results, the first heat-treated material according to the present invention has an area ratio of M 23 C 6 of 4.0 area% or less, 3.0 area% or less, or 2 in its cross-sectional structure. It is less than 0.0 area%. Preferably, for example, it is 1.5 area% or less, 1.0 area% or less, 0.7 area% or less, 0.5 area% or less. And more preferably, it is 0.3 area% or less, 0.2 area% or less, and 0.1 area% or less (including the case of 0 area%).
Further, the first heat-treated material according to the present invention preferably has a number density of M 23 C 6 of 10.0 × 10-2 / μm 2 or less or 7.0 × in its cross-sectional structure. 10-2 pieces / μm 2 or less, 5.0 × 10-2 pieces / μm 2 or less, 3.0 × 10-2 pieces / μm 2 or less. Further, as the solid solution of M 23 C 6 progresses, more preferably, for example, 1.5 × 10-2 pieces / μm 2 or less, 1.3 × 10 -2 pieces / μm 2 or less, 1. 0 × 10-2 pieces / μm 2 or less, 0.5 × 10 -2 pieces / μm 2 or less. And more preferably, for example, 0.3 × 10-2 pieces / μm 2 or less, 0.2 × 10 -2 pieces / μm 2 or less, 0.1 × 10 -2 pieces / μm 2 or less ( Including the case of 0 pieces / μm 2 ).
　また、本発明に係る第１の熱処理材は、好ましくは、その断面組織において、ＭＣの面積率が、例えば、１２．０面積％以下や、１０．０面積％以下のものである。そして、好ましくは、例えば、８．０面積％以下や、６．０面積％以下、５．０面積％以下である。また、好ましくは、例えば、０．１面積％以上や、１．０面積％以上、２．０面積％以上である。より好ましくは、例えば、２．５面積％以上や、３．１面積％以上、３．２面積％以上、３．５面積％以上である。そして、さらに好ましくは、３．８面積％以上や、４．２面積％以上、４．５面積％以上である。
　また、本発明に係る第１の熱処理材は、好ましくは、その断面組織において、ＭＣの個数密度が、例えば、５．０×１０－２個／μｍ２以下や、３．０×１０－２個／μｍ２以下、２．５×１０－２個／μｍ２以下のものである。より好ましくは、例えば、２．０×１０－２個／μｍ２以下や、１．７×１０－２個／μｍ２以下、１．５×１０－２個／μｍ２以下である。また、好ましくは、例えば、０．１×１０－２個／μｍ２以上や、０．５×１０－２個／μｍ２以上、１．０×１０－２個／μｍ２以上である。 Further, the first heat-treated material according to the present invention preferably has an MC area ratio of 12.0 area% or less or 10.0 area% or less in its cross-sectional structure. And, for example, it is 8.0 area% or less, 6.0 area% or less, 5.0 area% or less. Further, for example, it is preferably 0.1 area% or more, 1.0 area% or more, and 2.0 area% or more. More preferably, for example, it is 2.5 area% or more, 3.1 area% or more, 3.2 area% or more, and 3.5 area% or more. And more preferably, it is 3.8 area% or more, 4.2 area% or more, and 4.5 area% or more.
Further, the first heat-treated material according to the present invention preferably has a cross-sectional structure in which the number density of MCs is, for example, 5.0 × 10-2 / μm 2 or less, or 3.0 × 10-2. Pieces / μm 2 or less, 2.5 × 10-2 pieces / μm 2 or less. More preferably, for example, it is 2.0 × 10-2 pieces / μm 2 or less, 1.7 × 10-2 pieces / μm 2 or less, and 1.5 × 10-2 pieces / μm 2 or less. Further, for example, 0.1 × 10 -2 pieces / μm 2 or more, 0.5 × 10 -2 pieces / μm 2 or more, 1.0 × 10 -2 pieces / μm 2 or more.
　熱処理温度の上限は、特に限定はしないが、約１２５０℃程度である。そして、熱処理温度は、好ましくは１１５０℃を超える温度である。熱処理時間は第１の加工材の寸法、形状に応じて例えば、３０分以上、４５分以上、６０分以上とすることができ、上限についても１８０分以下、１２０分以下、９０分以下といったように、適宜決定すればよい。熱処理は、表面酸化を避けるために、真空、還元雰囲気、Ａｒなどの不活性雰囲気で行なうことが好ましいが、酸化雰囲気（例えば、大気雰囲気）で行なってもよい。酸化雰囲気で熱処理を行った場合、表面に酸化スケールが形成される。酸化スケールが形成されたまま冷間塑性加工を行なうと、割れや欠陥の起点となる虞がある。そこで、例えば研磨や研削などにより機械的に、または化学的に除去してもよい。線材の製造の場合は、センタレス研磨を用いてスケールの除去を行なうことが好ましい。また、酸化雰囲気で熱処理を行う場合、上記の熱処理時間は、例えば、１５０分以下、１００分以下、８０分以下といったように、短時間で完了することが好ましい。 The upper limit of the heat treatment temperature is not particularly limited, but is about 1250 ° C. The heat treatment temperature is preferably a temperature exceeding 1150 ° C. The heat treatment time can be, for example, 30 minutes or more, 45 minutes or more, 60 minutes or more depending on the size and shape of the first processed material, and the upper limit is 180 minutes or less, 120 minutes or less, 90 minutes or less. It may be decided as appropriate. The heat treatment is preferably carried out in a vacuum, a reducing atmosphere, an inert atmosphere such as Ar, in order to avoid surface oxidation, but may be carried out in an oxidizing atmosphere (for example, an atmospheric atmosphere). When the heat treatment is performed in an oxidizing atmosphere, an oxidation scale is formed on the surface. If cold plastic working is performed while the oxide scale is formed, it may become a starting point of cracks and defects. Therefore, it may be removed mechanically or chemically by, for example, polishing or grinding. In the case of wire rod production, it is preferable to remove the scale by using centerless polishing. When the heat treatment is performed in an oxidizing atmosphere, the heat treatment time is preferably completed in a short time, for example, 150 minutes or less, 100 minutes or less, 80 minutes or less.
　本発明では、第１の熱処理材の組織の結晶粒径（後述する結晶粒の最大径の平均粒径）を、１００μｍ以下にすることができる。好ましくは８０μｍ以下、より好ましくは６０μｍ以下、さらに好ましくは４０μｍ以下、よりさらに好ましくは２０μｍ以下である。結晶粒の微細化が、ナノ結晶粒の生成に効果的である。また、再結晶によって生成された結晶粒は粒内の歪みが少なく、かつ、この結晶粒を微細にすることで結晶粒界も増加するので、これに後述の冷間塑性加工を行なえば、そのときの加工歪みが組織の全体に均等に加わる。よって、上記の熱処理を行なうことにより、次工程の塑性加工での変形がより均一になり、加工中の異常変形や曲がりの発生を避けることもでき、歩留まりを飛躍的に向上させることができる。
　そして、第１の熱処理材の組織の結晶粒径を、１．４μｍ以上にすることができる。結晶粒を成長させることで、これが上述した炭化物の分布形態の調整に作用して、第１の熱処理材の塑性加工性が向上する。好ましくは１．５μｍ以上、より好ましくは１．８μｍ以上である。そして、上記の熱処理温度が高くなることによって、第１の熱処理材の結晶粒径は、例えば、２．０μｍ以上、３．０μｍ以上、４．０μｍ以上、５．０μｍ以上といった値に成長する。例えば、熱処理温度が、１１５０℃を超える温度や１２００℃以上の温度の場合、７．０μｍ以上や９．０μｍ以上といった値に成長する。 In the present invention, the crystal grain size of the structure of the first heat-treated material (the average grain size of the maximum diameter of the crystal grains described later) can be set to 100 μm or less. It is preferably 80 μm or less, more preferably 60 μm or less, still more preferably 40 μm or less, still more preferably 20 μm or less. The refinement of crystal grains is effective for the production of nanocrystal grains. In addition, the crystal grains generated by recrystallization have less distortion in the grains, and the grain boundaries also increase by making the crystal grains finer. Processing strain is evenly applied to the entire structure. Therefore, by performing the above heat treatment, the deformation in the plastic working of the next step becomes more uniform, it is possible to avoid the occurrence of abnormal deformation and bending during the machining, and the yield can be dramatically improved.
Then, the crystal grain size of the structure of the first heat-treated material can be made 1.4 μm or more. By growing the crystal grains, this acts on the adjustment of the distribution form of the carbides described above, and the plastic workability of the first heat-treated material is improved. It is preferably 1.5 μm or more, more preferably 1.8 μm or more. Then, as the heat treatment temperature rises, the crystal grain size of the first heat treatment material grows to, for example, 2.0 μm or more, 3.0 μm or more, 4.0 μm or more, 5.0 μm or more. For example, when the heat treatment temperature is a temperature exceeding 1150 ° C. or a temperature of 1200 ° C. or higher, it grows to a value of 7.0 μm or higher or 9.0 μm or higher.
　本発明では、第１の熱処理材の硬さは限定されない。そのため、上記の熱処理を行った後の冷却は急冷、空冷、放冷、炉冷などいずれでもよい。そして、第１の熱処理材の硬さは、例えば、４６０ＨＶ以下や４５０ＨＶ以下にできる。より好ましくは４３０ＨＶ以下である。さらに好ましくは４００ＨＶ以下であり、よりさらに好ましくは３８０ＨＶ以下である。熱処理後の冷却を、空冷よりも遅い冷却速度（例えば、炉冷による冷却速度）とすることで、第１の熱処理材の硬さをより低くすることができる。また、熱処理後の冷却速度を遅くすることで、冷却後の第１の熱処理材の表面割れを抑制するのに好ましく、続く塑性加工の円滑な進行に好ましい。
　なお、第１の熱処理材の硬さの下限は、特に限定しないが、２５０ＨＶ程度が現実的である。そして、第１の熱処理材の硬さを３００ＨＶ以上とすることもできる。第１の熱処理材の硬さは、それの断面で測定することができる。 In the present invention, the hardness of the first heat-treated material is not limited. Therefore, the cooling after the above heat treatment may be rapid cooling, air cooling, air cooling, furnace cooling, or the like. The hardness of the first heat-treated material can be, for example, 460 HV or less or 450 HV or less. More preferably, it is 430 HV or less. It is more preferably 400 HV or less, and even more preferably 380 HV or less. By setting the cooling rate after the heat treatment to a cooling rate slower than that of air cooling (for example, the cooling rate by furnace cooling), the hardness of the first heat treatment material can be made lower. Further, by slowing down the cooling rate after the heat treatment, it is preferable to suppress surface cracking of the first heat-treated material after cooling, and it is preferable for the smooth progress of the subsequent plastic working.
The lower limit of the hardness of the first heat-treated material is not particularly limited, but is realistically about 250 HV. Then, the hardness of the first heat-treated material can be set to 300 HV or more. The hardness of the first heat-treated material can be measured in cross section thereof.
　以上のことによって、冷間塑性加工に供する素材（第１の熱処理材）の炭化物に起因する塑性加工性の低下を抑制することができるので、上述したナノ結晶粒の生成効果が阻害されず有効に発揮されて、塑性加工中の素材に熱処理を行わないで、大きな加工率まで冷間加工を行なうことができる。 As a result, it is possible to suppress a decrease in plastic workability due to carbides of the material (first heat-treated material) to be subjected to cold plastic working, so that the above-mentioned effect of forming nanocrystal grains is not hindered and is effective. It is possible to perform cold working up to a large working rate without heat-treating the material being plastically worked.
（ｃ）第２の加工材を作製する工程
　次に、上記の素材（第１の熱処理材）に対して、冷間塑性加工を行う。そして、上記の素材が塑性加工性に優れ、塑性加工中も塑性加工性に優れることから、素材からの累積加工率が４０％以上となる複数回の冷間塑性加工を行うことができる。本発明は、従来の「熱間による」塑性加工によるものとは異なり、「冷間による」塑性加工によってＮｉ基超耐熱合金を製造するものである。そして、特に、γ’相の量が３５モル％以上のＮｉ基超耐熱合金においては、それを冷間塑性加工によって４０％以上の累積加工率を得ることができ、熱間塑性加工では加工することが困難であった上記のＮｉ基超耐熱合金を、比較的単純な工程かつ低コストで、例えば線材や細線にまで加工することができる。この達成のために、上記の冷間による塑性加工は、その塑性加工中に回復や再結晶が発生できないと考えられる低い温度領域で行うことが必要である。
　そこで本発明における上記の塑性加工温度は、「５００℃以下」とすることが好ましい。より好ましくは３００℃以下、さらに好ましくは１００℃以下、よりさらに好ましくは５０℃以下（例えば、室温）である。 (C) Step of Producing Second Processed Material Next, cold plastic working is performed on the above material (first heat-treated material). Since the above-mentioned material is excellent in plastic workability and is also excellent in plastic workability during plastic working, it is possible to perform a plurality of times of cold plastic working in which the cumulative work rate from the material is 40% or more. The present invention produces a Ni-based superheat resistant alloy by "cold" plastic working, as opposed to conventional "hot" plastic working. In particular, in the case of a Ni-based superheat resistant alloy having a γ'phase of 35 mol% or more, a cumulative working rate of 40% or more can be obtained by cold plastic working, and the alloy is processed by hot plastic working. The above-mentioned Ni-based superheat-resistant alloy, which has been difficult to achieve, can be processed into, for example, wire rods and fine wires in a relatively simple process and at low cost. In order to achieve this, it is necessary to carry out the above-mentioned cold plastic working in a low temperature region where recovery and recrystallization cannot occur during the plastic working.
Therefore, the plastic working temperature in the present invention is preferably "500 ° C. or lower". It is more preferably 300 ° C. or lower, still more preferably 100 ° C. or lower, and even more preferably 50 ° C. or lower (for example, room temperature).
　本発明のＮｉ基超耐熱合金の製造方法は、様々な形状物の製造に適用できる。そして、線材形態に好適であるが、板材、帯材などにも適用できる。そのため、本発明の製造方法により製造されるＮｉ基超耐熱合金は、線材（ｗｉｒｅ　ｍａｔｅｒｉａｌ）、板材（ｓｈｅｅｔ　ｍａｔｅｒｉａｌ）、帯材（ｓｔｒｉｐ　ｍａｔｅｒｉａｌ）の中間製品形状であることの他に、細線（ｗｉｒｅ　ｐｒｏｄｕｃｔ）、薄板（ｓｈｅｅｔ　ｐｒｏｄｕｃｔ）、薄帯（ｓｔｒｉｐ　ｐｒｏｄｕｃｔ）の最終製品形状であってもよい。板材（薄板）、帯材（薄帯）において、その寸法の関係は、線材（細線）のときの線径（直径）を、板厚または帯厚に読み替えることができる。 The method for producing a Ni-based superheat-resistant alloy of the present invention can be applied to the production of various shapes. Although it is suitable for the wire rod form, it can also be applied to a plate material, a strip material, and the like. Therefore, the Ni-based superheat-resistant alloy produced by the production method of the present invention has an intermediate product shape of a wire material, a sheet material, and a strip material, and also has a wire material. It may be the final product shape of a product), a sheet product, or a strip product. Regarding the relationship between the dimensions of the plate material (thin plate) and the strip material (thin strip), the wire diameter (diameter) of the wire rod (thin wire) can be read as the plate thickness or the strip thickness.
　とりわけＮｉ基超耐熱合金の熱間押出された素材が棒材の場合、断面積を圧縮する棒材加工を行なうことができる。この場合、Ｎｉ基超耐熱合金の「棒材」を出発材料として、この棒材に行う塑性加工の様態として、棒材中に均一に圧力を付与することができる「棒材の長手方向に垂直な断面の断面積を圧縮する加工」を施すことが好ましい。そして、この棒材の素材に、断面積（棒径）を塑性的に圧縮して、長さを伸ばしていく加工を行う。特に、Ｎｉ基超耐熱合金の線材を得る場合、線材よりも断面積（直径）が大きい「棒材」を塑性加工して作製することが効率的である。棒材の周面から軸心に向けて、累積加工率が４０％以上の塑性加工を行って、棒材の断面積を圧縮する。このような加工として、スエジング、カセットローラダイス伸線、孔型ダイス伸線などがある。
　他方、Ｎｉ基超耐熱合金の板材、帯材等の製造には、圧延加工を用いることもできる。 In particular, when the hot-extruded material of the Ni-based superheat-resistant alloy is a bar material, the bar material processing for compressing the cross section can be performed. In this case, using the Ni-based super heat-resistant alloy "bar" as the starting material, as a mode of plastic working on this bar, "vertical to the longitudinal direction of the bar" can uniformly apply pressure to the bar. It is preferable to perform a process of compressing the cross-sectional area of the cross section. Then, the material of this bar is subjected to a process of plastically compressing the cross-sectional area (bar diameter) to increase the length. In particular, when obtaining a wire rod of a Ni-based superheat-resistant alloy, it is efficient to plastically process a "bar rod" having a cross section (diameter) larger than that of the wire rod. Plastic working with a cumulative working rate of 40% or more is performed from the peripheral surface of the bar to the axial center to compress the cross-sectional area of the bar. Such processing includes swaging, cassette roller die wire drawing, hole type die wire drawing, and the like.
On the other hand, rolling processing can also be used for producing a plate material, a strip material, etc. of a Ni-based superheat resistant alloy.
　ここで、加工率とは、棒材をスエジングやダイス伸線を行なう場合には、減面率により表す。減面率は、塑性加工前の棒材の断面積Ａ０と、塑性加工後の線材や細線の断面積Ａ１との関係で、
　　［（Ａ０－Ａ１）／Ａ０］×１００（％）　　　　　　　　　　　（１）
の式で算出される。
　他方、圧延加工を行なう場合には、加工率は圧下率で表す。圧下率は、塑性加工前の素材の厚さをｔ０とし、塑性加工後の板材や帯材、薄板や薄帯の厚さをｔ１とすると、
　　［（ｔ０－ｔ１）／ｔ０］×１００（％）　　　　　　　　　　　（２）
の式で算出される。
　累積加工率とは塑性加工を複数回、あるいは複数パスにわたって行なった場合の、最終加工物の素材に対する加工率を示す。 Here, the processing rate is expressed by the surface reduction rate when the bar is swaged or the die is drawn. The surface reduction rate is the relationship between the cross-sectional area A 0 of the bar material before plastic working and the cross-sectional area A 1 of the wire rod or thin wire after plastic working.
[(A 0- A 1 ) / A 0 ] x 100 (%) (1)
It is calculated by the formula of.
On the other hand, when rolling is performed, the processing rate is expressed as a rolling reduction rate. As for the reduction ratio, assuming that the thickness of the material before plastic working is t 0 and the thickness of the plate or band after plastic working, or the thin plate or thin band is t 1 ,
[(T 0- t 1 ) / t 0 ] x 100 (%) (2)
It is calculated by the formula of.
The cumulative working rate indicates the working rate of the final work piece with respect to the material when plastic working is performed a plurality of times or over a plurality of passes.
　本発明では、例えば、上記の冷間塑性加工の素材からの累積加工率を４０％以上に高くする。
　この加工率の塑性加工は、一回の塑性加工で完了するのではなくて、複数回の塑性加工に分けて完了することができる。複数回の塑性加工の間には熱処理を行わない。ここでいう熱処理とは、回復や再結晶が発生するような高い温度領域での熱処理のことであり、例えば、５００℃を超える温度に加熱する熱処理である。このように冷間加工のパス間に熱処理が必要なく、複数の冷間強加工を連続的に実施して、累積加工率（累積減面率）を大きくすることができる。なお、強加工を行なったＮｉ基超耐熱合金は、組織中にナノ結晶粒の生成が観察できる。この機構はまだ完全に解明できていないが、ナノ結晶粒の生成により複数の冷間強加工を連続的に実施できると考えられる。このとき、４０％未満の加工率であると、製造工程の単純化、コスト低減の効果が小さくなる。すなわち冷間塑性加工を行なうことの実益の観点からは、累積加工率は、４０％以上にするとよい。累積加工率は、４５％以上が好ましく、５０％以上がより好ましく、５５％以上がさらに好ましい。累積加工率の上限は特に限定しないが、例えば、７０％程度とすることができる。そして、さらに、８０％程度、９０％程度とすることもできる。９０％を超えることもできる。本発明のＮｉ基超耐熱合金の製造方法の場合、高Ｃ含有量の合金の製造であるにも関わらず、塑性加工中に熱処理を行わないで、更に続けて大きな加工率まで冷間加工を行なうことができる。これらの塑性加工により、目標寸法（最終製品寸法）まで塑性加工を行なう。最終製品寸法の材料の硬さは５００ＨＶ以上にできる。
　なお、１回の塑性加工(パス)による加工率（減面率）は最大３０％とすることが好ましい。より好ましくは最大２８％とすることができる。一度の大きな加工率の塑性加工を行なわないことで、材料の割れや欠陥の抑制にさらに効果的である。
　本明細書で使用する用語「パス」については、上述したスエジングやダイス伸線、圧延といった種類の塑性加工において、一つの（または、一対でなる）ダイスやロールによって塑性加工されたときを「１パス」と称することができる。以後、「１パス」という用語を使用するとき、それは上記の１回の「塑性加工」を示している。 In the present invention, for example, the cumulative working rate from the above-mentioned cold plastic working material is increased to 40% or more.
The plastic working at this working rate is not completed by one plastic working, but can be completed by dividing into a plurality of plastic working. No heat treatment is performed during multiple plastic workings. The heat treatment referred to here is a heat treatment in a high temperature region where recovery or recrystallization occurs, and is, for example, a heat treatment for heating to a temperature exceeding 500 ° C. As described above, heat treatment is not required between the cold working passes, and a plurality of cold strong working can be continuously performed to increase the cumulative working rate (cumulative surface reduction rate). In the strongly processed Ni-based superheat resistant alloy, the formation of nanocrystal grains can be observed in the structure. Although this mechanism has not been completely elucidated yet, it is considered that a plurality of cold strong processes can be continuously performed by forming nanocrystal grains. At this time, if the processing rate is less than 40%, the effects of simplification of the manufacturing process and cost reduction are reduced. That is, from the viewpoint of the practical benefit of performing cold plastic working, the cumulative working rate should be 40% or more. The cumulative processing rate is preferably 45% or more, more preferably 50% or more, still more preferably 55% or more. The upper limit of the cumulative processing rate is not particularly limited, but can be, for example, about 70%. Further, it can be about 80% and about 90%. It can exceed 90%. In the case of the method for producing a Ni-based superheat-resistant alloy of the present invention, despite the production of an alloy having a high C content, heat treatment is not performed during plastic working, and cold working is continued to a large working rate. Can be done. By these plastic workings, plastic working is performed up to the target dimensions (final product dimensions). The hardness of the material of the final product size can be 500 HV or more.
The processing rate (surface reduction rate) by one plastic working (pass) is preferably 30% at maximum. More preferably, it can be up to 28%. By not performing plastic working at a large machining rate once, it is more effective in suppressing cracks and defects in the material.
Regarding the term "pass" used in the present specification, in the above-mentioned types of plastic working such as swaging, die wire drawing, and rolling, when plastic working is performed by one (or a pair of) dies or rolls, "1" is used. It can be called a "pass". Hereinafter, when the term "1 pass" is used, it refers to the above-mentioned one-time "plastic working".
　とりわけＮｉ基超耐熱合金の素材が棒材の場合、塑性加工性を向上させるためには、上記の塑性加工で、棒材中に均一かつ均等に圧力を付与することが重要と思われる。そして、このためには、棒材の周面から軸心に向けて、棒材の断面積を圧縮するような塑性加工が効果的である。このとき、塑性加工方式を限定する必要はない。但し、塑性加工される棒材の全周に均等に圧力を加える塑性加工方式が有利である。この具体例として、スエジング加工が挙げられる。スエジング加工は、棒材の全周を囲む複数のダイスを回転させながら、棒材の周面を鍛造するので、ナノ結晶粒の生成に好ましい。その他、カセットローラダイス伸線、孔型ダイス伸線などその他の塑性加工も適用可能である。 Especially when the material of the Ni-based super heat-resistant alloy is a bar, in order to improve the plastic workability, it is important to apply pressure uniformly and evenly to the bar by the above plastic working. For this purpose, plastic working that compresses the cross-sectional area of the bar from the peripheral surface of the bar toward the axis is effective. At this time, it is not necessary to limit the plastic working method. However, a plastic working method in which pressure is evenly applied to the entire circumference of the bar to be plastic working is advantageous. A specific example of this is swaging. The swaging process is preferable for the formation of nanocrystal grains because the peripheral surface of the bar is forged while rotating a plurality of dies surrounding the entire circumference of the bar. In addition, other plastic working such as cassette roller die drawing and hole type die drawing can also be applied.
（ｄ）第２の加工材に熱処理（最終熱処理）を行う工程
　上記の冷間塑性加工によって得られた合金を、最終製品形状とすることができる。例えば、「細線」や「薄板」、「薄帯」とすることができる。細線とは、その線径（直径）が、例えば、５ｍｍ以下、４ｍｍ以下、３ｍｍ以下といったものから、果ては２ｍｍ以下、１ｍｍ以下といった更に細いものである。また、薄板、薄帯とは、その厚さが、例えば、５ｍｍ以下、４ｍｍ以下、３ｍｍ以下といったものから、果ては２ｍｍ以下、１ｍｍ以下といった更に薄いものである。そして、細線、薄板、薄帯とは、その長さが、上記の線径や厚さに対して、例えば、５０倍以上、１００倍以上、３００倍以上といった更に長いものである。 (D) Step of heat-treating (final heat-treating) the second processed material The alloy obtained by the above-mentioned cold plastic working can be used as the final product shape. For example, it can be a "thin line", a "thin plate", or a "thin band". The thin wire has a wire diameter (diameter) of 5 mm or less, 4 mm or less, 3 mm or less, and finally 2 mm or less and 1 mm or less. Further, the thin plate and the thin band have a thickness of, for example, 5 mm or less, 4 mm or less, 3 mm or less, and finally 2 mm or less and 1 mm or less. The thin wire, the thin plate, and the thin band are longer in length, for example, 50 times or more, 100 times or more, and 300 times or more with respect to the above wire diameter and thickness.
　所定の寸法、形状に塑性加工した後、最終製品として供給する際、この冷間塑性加工を終えたままの状態で供給することができる。この場合の合金は、例えば、その組織中のγ相とγ’相とが延伸方向に延びた線状組織である。また、合金の硬さは５００ＨＶ以上である。そして、合金中に加工欠陥が存在することも考えられる。例えば、合金の長さ方向（つまり、塑性加工方向）の中心軸を含むような断面組織において、欠陥率が０．５面積％を超える加工欠陥である。但し、現実的には、１．０面積％以下である。そして、このような加工欠陥が存在することは、これ以上の塑性加工を行わない点で、問題がない。
　そして、必要に応じて、９００℃以上の温度で熱処理（例えば９００℃～１２００℃の温度で３０分～３時間保持）を施すことにより所望の等軸結晶組織にすることができる。この熱処理によって、例えば、硬さを５００ＨＶ未満や４５０ＨＶ以下、４２０ＨＶ以下に調整することが可能である。そして、例えば、３００ＨＶ以上や、３５０ＨＶ以上の硬さである。このことによって、最終製品を輸送形態や使用形態に見合った形態に曲げたり切断したりすることが容易になる。また、この熱処理によっても加工欠陥を修復でき、例えば、合金の長さ方向（つまり、塑性加工方向）の中心軸を含むような断面組織において、欠陥率を０．５面積％以下にできる。そして、塑性加工前の素材の状態で行った熱処理の効果も相まって、上記の欠陥率を、さらに、０．４面積％以下、０．３面積％以下、０．２面積％以下にできる。Ｎｉ基超耐熱合金の使用形態において、加工欠陥を低減しておくことが望まれる場合は、この熱処理を行うことができる。 After being plastically worked to a predetermined size and shape, when it is supplied as a final product, it can be supplied as it is after the cold plastic working. The alloy in this case is, for example, a linear structure in which the γ phase and the γ'phase in the structure extend in the stretching direction. The hardness of the alloy is 500 HV or more. It is also possible that processing defects are present in the alloy. For example, in a cross-sectional structure including the central axis in the length direction (that is, the plastic working direction) of the alloy, the defect rate is a processing defect exceeding 0.5 area%. However, in reality, it is 1.0 area% or less. The existence of such processing defects does not cause any problem in that no further plastic working is performed.
Then, if necessary, a desired equiaxed crystal structure can be obtained by performing heat treatment at a temperature of 900 ° C. or higher (for example, holding at a temperature of 900 ° C. to 1200 ° C. for 30 minutes to 3 hours). By this heat treatment, for example, the hardness can be adjusted to less than 500 HV, 450 HV or less, and 420 HV or less. And, for example, the hardness is 300 HV or more or 350 HV or more. This makes it easy to bend or cut the final product into a form suitable for the transportation form and usage form. Further, the processing defect can be repaired by this heat treatment, and for example, the defect rate can be reduced to 0.5 area% or less in the cross-sectional structure including the central axis in the length direction (that is, the plastic working direction) of the alloy. Then, combined with the effect of the heat treatment performed in the state of the material before plastic working, the above defect rate can be further reduced to 0.4 area% or less, 0.3 area% or less, and 0.2 area% or less. This heat treatment can be performed when it is desired to reduce processing defects in the usage form of the Ni-based superheat resistant alloy.
　上記の熱処理を行うことで、上記の等軸結晶組織中の結晶粒が成長していることが考えられる。例えば、結晶粒の粒径が、最大のもので線径に達しているかも知れない。そして、延伸方向に連なった炭化物集合体によって、結晶粒の粗大化が抑制される効果（ピン止め効果）が有効に機能すれば、結晶粒の成長が抑制される。この場合、上記の熱処理後の結晶粒の大きさは、断面組織における平均粒径で、例えば、１００μｍ以下、７５μｍ以下、５０μｍ以下、２５μｍ以下、１０μｍ以下、といった粒径となる。 It is considered that the crystal grains in the equiaxed crystal structure are grown by performing the above heat treatment. For example, the grain size of the crystal grains may reach the maximum wire diameter. Then, if the effect of suppressing the coarsening of the crystal grains (pinning effect) effectively functions by the carbide aggregates connected in the stretching direction, the growth of the crystal grains is suppressed. In this case, the size of the crystal grains after the heat treatment is the average particle size in the cross-sectional structure, for example, 100 μm or less, 75 μm or less, 50 μm or less, 25 μm or less, 10 μm or less.
　上記の最終熱処理は、表面酸化を避けるために、真空、還元雰囲気、Ａｒなどの不活性雰囲気で行なうことが好ましいが、酸化雰囲気（例えば、大気雰囲気）で行なってもよい。酸化雰囲気で熱処理を行った場合、表面に酸化スケールが形成される。製品の品質に支障を来たし得る場合、形成された酸化スケールを、例えば研磨や研削などにより機械的に、または化学的に除去してもよい。線材の製造の場合は、センタレス研磨を用いてスケールの除去を行なうことが好ましい。
　また、上記の最終熱処理を行うことに関わらず、最終製品の表面を、例えば、研磨や研削などにより機械的に、または化学的に仕上げ加工することができる。 The final heat treatment is preferably carried out in an inert atmosphere such as vacuum, reducing atmosphere or Ar in order to avoid surface oxidation, but may be carried out in an oxidizing atmosphere (for example, atmospheric atmosphere). When the heat treatment is performed in an oxidizing atmosphere, an oxidation scale is formed on the surface. If it may interfere with the quality of the product, the formed oxide scale may be removed mechanically or chemically, for example by polishing or grinding. In the case of wire rod production, it is preferable to remove the scale by using centerless polishing.
Further, regardless of the final heat treatment described above, the surface of the final product can be mechanically or chemically finished by, for example, polishing or grinding.
　以上、本発明によるＮｉ基超耐熱合金を説明してきた。本発明によれば、５００℃以下の温度で累積加工率が大きな（例えば、４０％以上の）Ｎｉ基超耐熱合金の塑性加工を行なうことができるため、熱間加工と熱処理を繰り返すなどの複雑な製造工程が必要なく、強冷間塑性加工が可能であり、塑性加工間の熱処理を省略できる。そのため、工程の単純化が達成でき製造コストの低減が可能になる。また、必要に応じては、欠陥率１．０面積％以下の加工欠陥の少ない製品、特に線材を得ることができる。この効果は、特に加工欠陥の発生しやすい炭素含有量が大きなＮｉ基超耐熱合金について顕著である。 The Ni-based super heat-resistant alloy according to the present invention has been described above. According to the present invention, since plastic working of a Ni-based superheat resistant alloy having a large cumulative working rate (for example, 40% or more) can be performed at a temperature of 500 ° C. or lower, it is complicated to repeat hot working and heat treatment. Strong cold plastic working is possible without the need for various manufacturing processes, and heat treatment between plastic working can be omitted. Therefore, the simplification of the process can be achieved and the manufacturing cost can be reduced. Further, if necessary, a product having a defect rate of 1.0 area% or less and few processing defects, particularly a wire rod, can be obtained. This effect is particularly remarkable for Ni-based superheat-resistant alloys having a large carbon content in which processing defects are likely to occur.
（ａ）第１の加工材を作製する工程
　真空溶解によって準備した溶湯を鋳造して、直径１００ｍｍ、質量１０ｋｇの円柱状のＮｉ基超耐熱合金のインゴットＡを作製した。インゴットＡの成分組成を表１に示す（質量％）。表１には、上記のインゴットＡの「γ’モル率」も示す。この値は、市販の熱力学平衡計算ソフト「ＪＭａｔＰｒｏ（Ｖｅｒｓｉｏｎ　８．０．１，Ｓｅｎｔｅ　Ｓｏｆｔｗａｒｅ　Ｌｔｄ．社製品）」を用いて計算した。この熱力学平衡計算ソフトに、表１に列挙された各元素の含有量を入力して、上記の「γ’モル率」（％）を求めた。 (A) Step of Producing First Processed Material The molten metal prepared by vacuum melting was cast to prepare an ingot A of a columnar Ni-based superheat resistant alloy having a diameter of 100 mm and a mass of 10 kg. The component composition of ingot A is shown in Table 1 (mass%). Table 1 also shows the "γ'molar rate" of the above ingot A. This value was calculated using commercially available thermodynamic equilibrium calculation software "JMatPro (Version 8.0.1, a product of Center Software Ltd.)". The content of each element listed in Table 1 was input to this thermodynamic equilibrium calculation software to obtain the above "γ'molar ratio" (%).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　この成分組成のインゴットＡに保持温度１２００℃、保持時間８時間の熱処理を施し、炉冷してから、インゴットＡの長さ方向に平行方向に長さ１５０ｍｍ、直径６０ｍｍの円柱形状の材料を採取した。この円柱形状の材料をＳＵＳ３０４製カプセルに封止して、熱間押出に供した。熱間押出の条件は、押出温度１１００℃、押出比１０（カプセルを含む）、押出ステム速度１５ｍｍ/ｓであった。熱間押出を行って、これを室温まで冷却後、上記のカプセル素材を除去することにより、直径２７ｍｍの押出材（第１の加工材）を得た。 The ingot A having this composition is heat-treated at a holding temperature of 1200 ° C. and a holding time of 8 hours, cooled in a furnace, and then a cylindrical material having a length of 150 mm and a diameter of 60 mm is collected in a direction parallel to the length of the ingot A. did. This cylindrical material was sealed in SUS304 capsules and subjected to hot extrusion. The conditions for hot extrusion were an extrusion temperature of 1100 ° C., an extrusion ratio of 10 (including capsules), and an extrusion stem speed of 15 mm / s. Hot extrusion was performed, the mixture was cooled to room temperature, and then the capsule material was removed to obtain an extruded material (first processed material) having a diameter of 27 mm.
（ｂ）第１の熱処理材（素材）を作製する工程
　上記の押出材を、大気中で、１０００℃、１０５０℃、１１００℃、１１５０℃、１２００℃のそれぞれの熱処理温度に加熱して、熱処理を施し（保持時間１時間）、炉冷して第１の熱処理材を得た（以下、「素材」と言う）。また、熱処理温度が１２００℃のものについては、空冷もした。そして、これら６条件の熱処理を施して得た６種の素材に、熱処理自体を行わなかった（熱間押出のままの）素材も加えて、計７種の素材１～７［素材１（熱処理なし）、素材２（熱処理温度１０００℃）、素材３（同１０５０℃）、素材４（同１１００℃）、素材５（同１１５０℃）、素材６（同１２００℃）、素材７（同１２００℃。但し、熱処理後、空冷）］を作製した。 (B) Step of Producing First Heat Treatment Material (Material) The extruded material is heated to heat treatment temperatures of 1000 ° C., 1050 ° C., 1100 ° C., 1150 ° C., and 1200 ° C. in the air for heat treatment. (Holding time: 1 hour) and cooled in a furnace to obtain a first heat-treated material (hereinafter referred to as "material"). In addition, those having a heat treatment temperature of 1200 ° C. were also air-cooled. Then, in addition to the 6 types of materials obtained by performing the heat treatment under these 6 conditions, the materials that have not been heat-treated (as they are hot extruded) are added, and a total of 7 types of materials 1 to 7 [Material 1 (heat treatment). None), Material 2 (heat treatment temperature 1000 ° C), Material 3 (1050 ° C), Material 4 (1100 ° C), Material 5 (1150 ° C), Material 6 (1200 ° C), Material 7 (1200 ° C) However, after heat treatment, air cooling)] was prepared.
　素材１～７を、軸線方向に平行に半割切断して、その切断面のミクロ組織（結晶粒径、炭化物形態）および硬さを評価した。
　素材１～７の走査型電子顕微鏡（ＳＥＭ像）観察による上記切断面の断面ミクロ組織を、図４～１０の順で示す。このとき、断面ミクロ組織の倍率は２０００倍を基本とすることができる。但し、結晶粒径が大きい場合、より多くの結晶粒数を確認するために、倍率を小さくすることができ、例えば、後述のＥＢＳＤによる結晶粒径が８μｍを超えるような場合、倍率を１０００倍にすることができる（素材６、７）。観察場所は、上記の切断面において、素材の表面から軸心に向かってＤ／４（Ｄは押出材直径）の距離入った位置とした。それぞれのミクロ組織には各種の炭化物（ＭＣ、Ｍ２３Ｃ６等）が観察されたところ（図中の分散物）、熱処理温度が１２００℃の素材６、７のミクロ組織には、Ｍ２３Ｃ６が実質的に確認されなかった（０．１×１０－２個／μｍ２以下であった）。硬さの評価は、上記の切断面において、素材の表面から軸心に向かってＤ／２の距離入った位置（つまり、軸心の位置）とした。 Materials 1 to 7 were cut in half parallel to the axial direction, and the microstructure (crystal grain size, carbide morphology) and hardness of the cut surface were evaluated.
The cross-sectional microstructures of the cut surfaces as observed by scanning electron microscopes (SEM images) of materials 1 to 7 are shown in the order of FIGS. 4 to 10. At this time, the magnification of the cross-sectional microstructure can be basically 2000 times. However, when the crystal grain size is large, the magnification can be reduced in order to confirm a larger number of crystal grains. For example, when the crystal grain size by EBSD described later exceeds 8 μm, the magnification is 1000 times. (Materials 6 and 7). The observation location was a position within a distance of D / 4 (D is the diameter of the extruded material) from the surface of the material toward the axis on the above-mentioned cut surface. Various carbide Each microstructure (MC, M 23 C 6, etc.) where it was observed (dispersion in the figure), the microstructure of the material 6, 7 of the heat treatment temperature is 1200 ° C., M 23 C No. 6 was substantially not confirmed (0.1 × 10-2 pieces / μm 2 or less). The hardness was evaluated at a position within a distance of D / 2 from the surface of the material toward the axis (that is, the position of the axis) on the above-mentioned cut surface.
　炭化物の分布形態については、上記の観察場所をＥＰＭＡ（電子線マイクロアナライザー）で分析することで、ＭＣの分布形態はそれを構成する金属元素であるＮｂのマッピング図で、Ｍ２３Ｃ６のそれは同じくＣｒのマッピング図で、確認することができる。これらＮｂのマッピング図およびＣｒのマッピング図を、図４～１０に併載しておく。図９（素材６）、図１０（素材７）のＣｒのマッピング図では、Ｃｒが全面に亘って均等に分布しており（つまり、Ｃｒが基地中に固溶しており）、Ｃｒの偏在が（つまり、Ｃｒの炭化物が）実質的に認められなかった。そして、この図４～１０のマッピング図を１視野（倍率２０００倍なら５０μｍ×６５μｍ、倍率１０００倍なら１００μｍ×１３０μｍ）として、この１視野で確認した炭化物の面積率および個数密度を、この１視野と縦横で隣り合う別の３視野でも確認して（つまり、倍率２０００倍なら１００μｍ×１３０μｍ、倍率１０００倍なら２００μｍ×２６０μｍ）、これら４視野分の値を平均した値を、本発明に係る第１の熱処理材の炭化物形態として求めた。 Regarding the distribution form of carbides, by analyzing the above observation location with EPMA (electron probe microanalyzer), the distribution form of MC is a mapping diagram of Nb, which is a metal element that composes it, and that of M 23 C 6 is It can also be confirmed in the Cr mapping diagram. The Nb mapping diagram and the Cr mapping diagram are shown in FIGS. 4 to 10. In the Cr mapping diagram of FIGS. 9 (material 6) and 10 (material 7), Cr is evenly distributed over the entire surface (that is, Cr is solid-solved in the base), and Cr is unevenly distributed. (Ie, no carbides of Cr) were found. Then, the mapping diagram of FIGS. 4 to 10 is set as one field of view (50 μm × 65 μm at 2000 times magnification, 100 μm × 130 μm at 1000 times magnification), and the area ratio and number density of carbides confirmed in this one field of view are shown in this one field of view. (That is, 100 μm × 130 μm at a magnification of 2000 times, 200 μm × 260 μm at a magnification of 1000 times), and the average value of these four fields of view is the value according to the present invention. It was determined as the carbide form of the heat treatment material of 1.
　そして、上記の観察場所において、素材１～７の結晶粒径をＥＢＳＤ像で評価した。ＥＢＳＤの測定条件は、上記の走査型電子顕微鏡（ＪＩＢ－４７００Ｆ（日本電子社製））に付属したＥＢＳＤ測定システム「Ａｚｔｅｃ　Ｖｅｒｓｉｏｎ　３．２（Ｏｘｆｏｒｄ　Ｉｎｓｔｒｕｍｅｎｔｓ社製）」を使用して、倍率：２０００倍（素材６、７は１０００倍）、スキャンステップ：０．１μｍとし、結晶粒の定義は方位差１５°以上を粒界とした。このときのＥＢＳＤ像を、図４～１０に併載しておく。そして、この測定条件および定義によって認識された粒のうちから上記のＥＰＭＡで確認したＭＣ炭化物のものを除いた粒を結晶粒とし、この結晶粒について、個々の結晶粒の最大径（最大長さ）と個数との関係による結晶粒径分布を確認し、結晶粒の最大径の平均直径を求めた。そして、この１視野のＥＢＳＤ像で求めた結晶粒の最大径の平均直径を、上記の炭化物形態のときと同様の要領で、この１視野と縦横で隣り合う別の３視野でも求めて、これら４視野分の値を平均した値を、本発明に係る第１の熱処理材の結晶粒径として求めた。
　以上の結果を表２に示す。また、この結果について、熱処理温度と炭化物形態（面積率、個数密度）、結晶粒径および硬さそれぞれとの関係を図示したものを、素材７（空冷）のものを除いて、図１１、図１２、図１３および図１４の順に示す。図１１および図１２において、熱処理温度が上がると、１１００℃と１１５０℃との間で、ＭＣの面積率および個数密度と、Ｍ２３Ｃ６の面積率および個数密度とが逆転し、ＭＣの方が面積率、個数密度が多くなっている。 Then, at the above-mentioned observation place, the crystal grain size of the materials 1 to 7 was evaluated by the EBSD image. The EBSD measurement conditions are as follows: Magnification: 2000 using the EBSD measurement system "Aztec Version 3.2 (Oxford Instruments)" attached to the above scanning electron microscope (JIB-4700F (JEOL Ltd.)). Double (1000 times for materials 6 and 7), scan step: 0.1 μm, and the definition of crystal grains was defined as grain boundaries with an orientation difference of 15 ° or more. The EBSD images at this time are also shown in FIGS. 4 to 10. Then, from the grains recognized by these measurement conditions and definitions, the grains excluding those of the MC carbide confirmed by the above EPMA are defined as crystal grains, and for these crystal grains, the maximum diameter (maximum length) of each crystal grain is used. ) And the number of crystals, the crystal grain size distribution was confirmed, and the average diameter of the maximum diameter of the crystal grains was determined. Then, the average diameter of the maximum diameters of the crystal grains obtained in the EBSD image of this one field of view is obtained in the same manner as in the case of the above-mentioned carbide form in another three fields of view vertically and horizontally adjacent to this one field of view. The average value of the values for the four fields of view was determined as the crystal grain size of the first heat-treated material according to the present invention.
The above results are shown in Table 2. Regarding this result, FIGS. 11 and 11 show the relationship between the heat treatment temperature and the carbide morphology (area ratio, number density), crystal grain size and hardness, except for the material 7 (air-cooled). 12, FIG. 13 and FIG. 14 are shown in this order. In FIGS. 11 and 12, when the heat treatment temperature rises, the area ratio and number density of MC and the area ratio and number density of M 23 C 6 are reversed between 1100 ° C. and 1150 ° C., and the MC However, the area ratio and the number density are high.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（ｃ）第２の加工材を作製する工程
　次に、素材１～７から直径６ｍｍ、長さ６０ｍｍの棒材を切り出した。棒材の長手方向は押出材の軸線方向に平行に取った。
　この棒材に、回転式スエジング装置を用いて、室温（約２５℃）で１２パスまでの複数パスの冷間塑性加工を施して、それぞれの記号に対応する第２の加工材１～７を作製した。各パスの加工率（減面率）は３０％以下とした。また、各パス間には熱処理を行わなかった。パススケジュールを表３に示す。そして、このパススケジュールで、最初の６．０ｍｍの直径から加工可能であった直径および減面率（つまり、加工材が破断したパス前の直径および減面率）を評価した。また、そのときの硬さ（軸線方向に平行に半割切断したときの、軸心の位置での断面硬さ）も測定した。結果を表４に示す。 (C) Step of Producing Second Processed Material Next, a rod material having a diameter of 6 mm and a length of 60 mm was cut out from the materials 1 to 7. The longitudinal direction of the bar was taken parallel to the axial direction of the extruded material.
Using a rotary swaging device, this bar is subjected to cold plastic working in multiple passes up to 12 passes at room temperature (about 25 ° C), and the second processed materials 1 to 7 corresponding to each symbol are applied. Made. The processing rate (reduction rate) of each pass was set to 30% or less. In addition, no heat treatment was performed between each pass. The path schedule is shown in Table 3. Then, in this pass schedule, the diameter and the surface reduction rate that could be processed from the initial diameter of 6.0 mm (that is, the diameter and the surface reduction rate before the pass in which the processed material broke) were evaluated. In addition, the hardness at that time (the cross-sectional hardness at the position of the axial center when cut in half parallel to the axial direction) was also measured. The results are shown in Table 4.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４の結果について、その冷間塑性加工前の押出材に施した熱処理の温度と、冷間塑性加工性（減面率）との関係を図３に示す。図３より、押出材に熱処理を施したことで、素材の加工性が飛躍的に向上した（ステージ１）。そして、熱処理温度が１０００℃を超えた辺りから、一旦、加工性が低下する傾向となるものの（ステージ２）、当初の加工性は維持して、熱処理温度が１１５０℃を超えた辺りから再び上昇に転じて、加工性がさらに向上した（ステージ３）。 Regarding the results in Table 4, the relationship between the temperature of the heat treatment applied to the extruded material before the cold plastic working and the cold plastic working (surface reduction rate) is shown in FIG. From FIG. 3, by heat-treating the extruded material, the workability of the material was dramatically improved (stage 1). Then, although the workability tends to decrease once when the heat treatment temperature exceeds 1000 ° C. (stage 2), the initial workability is maintained and the heat treatment temperature rises again when the heat treatment temperature exceeds 1150 ° C. The workability was further improved (stage 3).
　以上、実施例によりＮｉ基超耐熱合金の細線を、冷間塑性加工により製造できることを示した。本発明の製造方法により製造したＮｉ基超耐熱合金は冷間で塑性加工することで、任意の線径の線材等に加工できる。本実施例は、線材の製造について行なったが、板材など他の形状の製造への適用も可能である。

  As described above, it has been shown that a thin wire of a Ni-based superheat-resistant alloy can be produced by cold plastic working according to the examples. The Ni-based superheat-resistant alloy produced by the production method of the present invention can be processed into a wire rod or the like having an arbitrary wire diameter by plastic working in the cold. Although this embodiment was performed on the production of wire rods, it can also be applied to the production of other shapes such as plate materials.

Claims (7)

  1. 　Ｎｉ基超耐熱合金の製造方法であって、
    （ａ）炭素含有量が０．０５～０．２５質量％であり、かつ７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有する材料に、９００℃以上の温度で塑性加工を行なった後に冷却して、第１の加工材を作製する工程と、
    （ｂ）前記第１の加工材を９００℃以上の温度に加熱して熱処理を行い、第１の熱処理材を作製する工程と
    を含む、Ｎｉ基超耐熱合金の製造方法。     It is a manufacturing method of Ni-based super heat-resistant alloy.
    (A) A material having a carbon content of 0.05 to 0.25% by mass and a component composition in which the equilibrium precipitation amount of the gamma prime phase at 700 ° C. is 35 mol% or more is plasticized at a temperature of 900 ° C. or higher. The process of producing the first processed material by cooling after processing and
    (B) A method for producing a Ni-based superheat-resistant alloy, which comprises a step of heating the first processed material to a temperature of 900 ° C. or higher to perform heat treatment to prepare the first heat-treated material.
  2. （ｃ）前記第１の熱処理材に、５００℃以下の温度で塑性加工を行ない、第２の加工材を作製する工程と
    をさらに含む、請求項１に記載されたＮｉ基超耐熱合金の製造方法。     (C) The production of the Ni-based superheat-resistant alloy according to claim 1, further comprising a step of plastically working the first heat-treated material at a temperature of 500 ° C. or lower to prepare a second processed material. Method.
  3. （ｄ）前記第２の加工材に、９００℃以上の温度で熱処理を行う工程と
    をさらに含む、請求項２に記載されたＮｉ基超耐熱合金の製造方法。     (D) The method for producing a Ni-based superheat-resistant alloy according to claim 2, further comprising a step of heat-treating the second processed material at a temperature of 900 ° C. or higher.
  4. 　前記Ｎｉ基超耐熱合金が、質量％で、
    　Ｃ：０．０５～０．２５％、
    　Ｃｒ：８．０～２５．０％、
    　Ａｌ：０．５～８．０％、
    　Ｔｉ：０．４～７．０％、
    　Ｃｏ：０～２８．０％、
    　Ｍｏ：０～８．０％、
    　Ｗ：０～１５．０％、
    　Ｎｂ：０～４．０％、
    　Ｔａ：０～５．０％、
    　Ｆｅ：０～１０．０％、
    　Ｖ：０～１．２％、
    　Ｈｆ：０～３．０％、
    　Ｂ：０～０．３００％、
    　Ｚｒ：０～０．３００％
    を含み、残部がＮｉおよび不純物からなる、請求項１から請求項３までのいずれか１項に記載されたＮｉ基超耐熱合金の製造方法。     The Ni-based super heat-resistant alloy is in mass%.
    C: 0.05-0.25%,
    Cr: 8.0-25.0%,
    Al: 0.5-8.0%,
    Ti: 0.4-7.0%,
    Co: 0-28.0%,
    Mo: 0-8.0%,
    W: 0 to 15.0%,
    Nb: 0-4.0%,
    Ta: 0-5.0%,
    Fe: 0 to 10.0%,
    V: 0-1.2%,
    Hf: 0-3.0%,
    B: 0 to 0.300%,
    Zr: 0 to 0.300%
    The method for producing a Ni-based superheat-resistant alloy according to any one of claims 1 to 3, wherein the method comprises the above, and the balance is composed of Ni and impurities.
  5. 　冷間塑性加工用のＮｉ基超耐熱合金であって、
    　炭素含有量が０．０５～０．２５質量％であり、かつ７００℃におけるガンマプライム相の平衡析出量が３５モル％以上の成分組成を有し、
    　断面組織において、Ｍ２３Ｃ６の面積率が４．０面積％以下であり、結晶粒の最大径の平均粒径が１．４～１００μｍである、Ｎｉ基超耐熱合金。     Ni-based super heat-resistant alloy for cold plastic working
    It has a component composition having a carbon content of 0.05 to 0.25% by mass and an equilibrium precipitation amount of the gamma prime phase at 700 ° C. of 35 mol% or more.
    A Ni-based superheat-resistant alloy having an area ratio of M 23 C 6 of 4.0 area% or less and an average particle size of the maximum diameter of crystal grains of 1.4 to 100 μm in the cross-sectional structure.
  6. 　硬さが４６０ＨＶ以下である、請求項５に記載されたＮｉ基超耐熱合金。 The Ni-based superheat-resistant alloy according to claim 5, which has a hardness of 460 HV or less.
  7. 　　前記Ｎｉ基超耐熱合金が、質量％で、
    　Ｃ：０．０５～０．２５％、
    　Ｃｒ：８．０～２５．０％、
    　Ａｌ：０．５～８．０％、
    　Ｔｉ：０．４～７．０％、
    　Ｃｏ：０～２８．０％、
    　Ｍｏ：０～８．０％、
    　Ｗ：０～１５．０％、
    　Ｎｂ：０～４．０％、
    　Ｔａ：０～５．０％、
    　Ｆｅ：０～１０．０％、
    　Ｖ：０～１．２％、
    　Ｈｆ：０～３．０％、
    　Ｂ：０～０．３００％、
    　Ｚｒ：０～０．３００％
    を含み、残部がＮｉおよび不純物からなる、請求項５または請求項６に記載されたＮｉ基超耐熱合金。

          The Ni-based super heat-resistant alloy is in mass%.
    C: 0.05-0.25%,
    Cr: 8.0-25.0%,
    Al: 0.5-8.0%,
    Ti: 0.4-7.0%,
    Co: 0-28.0%,
    Mo: 0-8.0%,
    W: 0 to 15.0%,
    Nb: 0-4.0%,
    Ta: 0-5.0%,
    Fe: 0 to 10.0%,
    V: 0-1.2%,
    Hf: 0-3.0%,
    B: 0 to 0.300%,
    Zr: 0 to 0.300%
    The Ni-based superheat resistant alloy according to claim 5 or 6, wherein the balance is composed of Ni and impurities.
PCT/JP2020/001725 2019-03-26 2020-01-20 Method for producing ni-based super-heat-resistant alloy, and ni-based super-heat-resistant alloy WO2020195049A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2020520084A JP6826766B1 (en) 2019-03-26 2020-01-20 Manufacturing method of Ni-based super heat-resistant alloy and Ni-based super heat-resistant alloy

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2019-059122 2019-03-26
JP2019059122 2019-03-26
JP2019-144497 2019-08-06
JP2019144497 2019-08-06

Publications (1)

Publication Number Publication Date
WO2020195049A1 true WO2020195049A1 (en) 2020-10-01

Family

ID=72609738

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/001725 WO2020195049A1 (en) 2019-03-26 2020-01-20 Method for producing ni-based super-heat-resistant alloy, and ni-based super-heat-resistant alloy

Country Status (2)

Country Link
JP (1) JP6826766B1 (en)
WO (1) WO2020195049A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112281099A (en) * 2020-10-13 2021-01-29 江苏联捷冶金设备有限公司 Tungsten-cobalt alloy sink roll and preparation method thereof
CN113584370A (en) * 2021-07-30 2021-11-02 北京北冶功能材料有限公司 Low-density high-strength high-entropy high-temperature alloy and preparation method thereof
CN113604706A (en) * 2021-07-30 2021-11-05 北京北冶功能材料有限公司 Low-density low-expansion high-entropy high-temperature alloy and preparation method thereof
CN114752817A (en) * 2022-04-08 2022-07-15 南京工程学院 High-temperature alloy die material and preparation method and application thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014070230A (en) * 2012-09-27 2014-04-21 Hitachi Metals Ltd METHOD FOR PRODUCING Ni-BASED SUPERALLOY
JP2017514998A (en) * 2014-03-14 2017-06-08 オウベル・アンド・デュヴァル Precipitation hardening nickel alloy, parts made of said alloy, and method for producing the same
WO2018155446A1 (en) * 2017-02-21 2018-08-30 日立金属株式会社 Ni-based super heat-resistant alloy and method for manufacturing same
WO2019004176A1 (en) * 2017-06-30 2019-01-03 日立金属株式会社 Method for manufacturing ni-based heat-resistant superalloy wire, and ni-based heat-resistant superalloy wire

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014070230A (en) * 2012-09-27 2014-04-21 Hitachi Metals Ltd METHOD FOR PRODUCING Ni-BASED SUPERALLOY
JP2017514998A (en) * 2014-03-14 2017-06-08 オウベル・アンド・デュヴァル Precipitation hardening nickel alloy, parts made of said alloy, and method for producing the same
WO2018155446A1 (en) * 2017-02-21 2018-08-30 日立金属株式会社 Ni-based super heat-resistant alloy and method for manufacturing same
WO2019004176A1 (en) * 2017-06-30 2019-01-03 日立金属株式会社 Method for manufacturing ni-based heat-resistant superalloy wire, and ni-based heat-resistant superalloy wire

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112281099A (en) * 2020-10-13 2021-01-29 江苏联捷冶金设备有限公司 Tungsten-cobalt alloy sink roll and preparation method thereof
CN113584370A (en) * 2021-07-30 2021-11-02 北京北冶功能材料有限公司 Low-density high-strength high-entropy high-temperature alloy and preparation method thereof
CN113604706A (en) * 2021-07-30 2021-11-05 北京北冶功能材料有限公司 Low-density low-expansion high-entropy high-temperature alloy and preparation method thereof
CN114752817A (en) * 2022-04-08 2022-07-15 南京工程学院 High-temperature alloy die material and preparation method and application thereof
CN114752817B (en) * 2022-04-08 2022-09-23 南京工程学院 High-temperature alloy die material and preparation method and application thereof

Also Published As

Publication number Publication date
JPWO2020195049A1 (en) 2021-04-08
JP6826766B1 (en) 2021-02-10

Similar Documents

Publication Publication Date Title
JP6422045B1 (en) Ni-base superalloy and manufacturing method thereof
JP6889418B2 (en) Manufacturing method of Ni-based super heat-resistant alloy and Ni-based super heat-resistant alloy
EP3441489B1 (en) Method for manufacturing ni-based alloy member
US11085104B2 (en) Method for manufacturing Ni-based heat-resistant superalloy wire, and Ni-based heat-resistant super alloy wire
WO2020195049A1 (en) Method for producing ni-based super-heat-resistant alloy, and ni-based super-heat-resistant alloy
JP6150192B2 (en) Method for producing Ni-base superalloy
JP4493029B2 (en) Α-β type titanium alloy with excellent machinability and hot workability
JP5652730B1 (en) Ni-base superalloy and manufacturing method thereof
JP6965986B2 (en) Manufacturing method of α + β type titanium alloy wire and α + β type titanium alloy wire
JP6826879B2 (en) Manufacturing method of Ni-based super heat-resistant alloy
EP3012337B1 (en) Hot-forged ti-al-based alloy and method for producing same
JP6719216B2 (en) α-β type titanium alloy
JP6748951B2 (en) Method for producing Ni-base superheat-resistant alloy and Ni-base superheat-resistant alloy
JP2018154922A (en) α+β TYPE TITANIUM ALLOY EXTRUDED SHAPE
JP2021130861A (en) PRODUCTION METHOD OF α+β TYPE TITANIUM ALLOY BAR MATERIAL
CN113508183A (en) Bar material
JP2019183263A (en) Ni BASED SUPERALLOY MATERIAL FOR COLD WORKING
WO2017170433A1 (en) Method for producing ni-based super heat-resistant alloy
EP3520915A1 (en) Method of manufacturing ni-based super heat resistant alloy extruded material, and ni-based super heat resistant alloy extruded material
TWI564398B (en) Nickel-based alloy and method of producing thereof
WO2016152663A1 (en) α-β TITANIUM ALLOY
EP4299776A1 (en) Tial alloy for forging, tial alloy material, and method for producing tial alloy material
JP2021011601A (en) METHOD FOR PRODUCING Ni-BASED SUPERALLOY
JP2020001047A (en) Ni-BASED SUPER HEAT RESISTANT ALLOY WELDING MATERIAL
JPH06240391A (en) Nickel-tungsten alloy excellent in high temperature strength, its production and jig for hot working using it

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2020520084

Country of ref document: JP

Kind code of ref document: A

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20776711

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20776711

Country of ref document: EP

Kind code of ref document: A1