WO2024075560A1 - Procédé de production de superalliage à base de ni empêchant la détérioration de la résistance à l'oxydation due à sb, et élément en superalliage à base de ni empêchant la détérioration de la résistance à l'oxydation due à sb - Google Patents

Procédé de production de superalliage à base de ni empêchant la détérioration de la résistance à l'oxydation due à sb, et élément en superalliage à base de ni empêchant la détérioration de la résistance à l'oxydation due à sb Download PDF

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WO2024075560A1
WO2024075560A1 PCT/JP2023/034641 JP2023034641W WO2024075560A1 WO 2024075560 A1 WO2024075560 A1 WO 2024075560A1 JP 2023034641 W JP2023034641 W JP 2023034641W WO 2024075560 A1 WO2024075560 A1 WO 2024075560A1
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mass
raw material
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superalloy
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Japanese (ja)
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京子 川岸
広史 原田
忠晴 横川
千尋 田畑
裕俊 前澤
淳 埋橋
忠勝 大久保
高田　裕治
進補 鈴木
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国立研究開発法人物質・材料研究機構
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Publication of WO2024075560A1 publication Critical patent/WO2024075560A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/04—Influencing the temperature of the metal, e.g. by heating or cooling the mould
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/02—Making non-ferrous alloys by melting
    • 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
    • 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

Definitions

  • the present invention relates to a method for producing a Ni-based superalloy that prevents the deterioration of oxidation resistance caused by Sb, and to a Ni-based superalloy component that prevents the deterioration of oxidation resistance caused by Sb.
  • Ni-base superalloys are used as turbine blades for jet engines, gas turbines, and the like.
  • various elements are used to improve high-temperature properties, and this has led to issues such as increased material costs and uneven supply of raw materials.
  • elements known to impair the high-temperature properties of Ni-base superalloys include sulfur (S) and antimony (Sb). Standards stipulate upper limits for the content ratios of these elements that impair high-temperature properties.
  • the allowable Sb ratio in the Ni-base superalloy AMS2280 for aerospace use is 50 ppm (see Non-Patent Document 1).
  • the allowable Sb ratio in Ni-base heat-resistant alloys used for boiler piping in thermal power plants and the like is 50 ppm (0.005 mass%) (see Patent Document 1, paragraphs [0057] and [0058]).
  • the composition ratio of Sb in the Ni-base heat-resistant alloy exceeds 50 ppm, a significant decrease in ductility and toughness after high-temperature, long-term heating at temperatures of 700°C or higher for 10,000 hours or more becomes a problem.
  • Sb is mixed in as an impurity element during the raw material melting process.
  • Non-Patent Document 2 describes that an alloy produced by adding Sb, a low-melting point metal impurity, to a master ingot and melting it in an Al 2 O 3 crucible contains 1.1 ppm of Sb, and that in a repeated oxidation test in which one cycle was 1100°C-1h and room temperature-1h, a clear mass loss was observed after 50 cycles.
  • the problem is that the oxidation resistance of Ni-based superalloys is deteriorated by the low melting point metal impurity element Sb.
  • Sb low melting point metal impurity element
  • Ni-based superalloys having the same oxidation resistance as conventional ones using materials with a relatively high impurity content (low grade), such as recycled materials instead of the high purity materials required for the manufacture of conventional Ni-based superalloys for turbine blades, it would be desirable from the viewpoint of material costs and raw material suppliers.
  • the present invention is intended to solve the above-mentioned problems, and aims to provide a manufacturing method for a Ni-base superalloy in which the deterioration of oxidation resistance of the Ni-base superalloy due to the low-melting point metal impurity element Sb can be prevented by using an additive element that can prevent the deterioration of oxidation resistance of the Ni-base superalloy due to Sb, even if Sb is mixed in during the raw material melting process and/or even if a material with a relatively high impurity content is used in the production of the Ni-base superalloy, and a Ni-base superalloy component in which the deterioration of oxidation resistance due to Sb is prevented.
  • the method for producing a Ni-base superalloy of the present invention includes the steps of: putting a Ni-base superalloy raw material containing Sb of a predetermined composition into a crucible, melting it in a vacuum by high-frequency induction melting furnace, adding a necessary amount of Ca (calcium) to the molten Ni-base superalloy raw material to prevent the oxidation resistance inhibiting action of Sb to the molten Ni-base superalloy raw material; stabilizing the molten metal at 1560 to 1640 ° C.
  • a raw material for Ni-base superalloys containing Sb of a predetermined composition refers to a material having a composition as specified in, for example, [10] or [11]. However, it is not required that the raw material satisfy the conditions regarding the content of Sb and Ca before being put into the crucible.
  • the conditions for such a stabilization treatment are determined taking into consideration the fact that the casting temperature is generally set to +90-170°C above the solidification start temperature of the casting alloy, that the melting point of Ni is 1455°C, and that the melting points of each element used as a constituent element of the target Ni-base superalloy.
  • the crucible is a CaO crucible
  • the Ca (calcium) is supplied to the molten Ni-base superalloy raw material by contact between the CaO crucible and the molten Ni-base superalloy raw material.
  • the crucible is an Al 2 O 3 crucible or an MgO crucible
  • the Ca (calcium) is added to the Ni-base superalloy raw material or a molten metal of the Ni-base superalloy raw material by adding CaO equivalent to 0.2% to 5% by weight based on the Ni-base superalloy raw material.
  • the CaO is preferably in the form of granules having a particle size of 1 to 10 mm.
  • the crucible is an Al2O3 crucible or an MgO crucible
  • the Ca (calcium) is added to the Ni-base superalloy raw material or a molten metal of the Ni-base superalloy raw material in an amount equivalent to 0.33 to 100 times the amount of Sb by mass ratio.
  • the Ca (calcium) is supplied as a component of CaF2 , and CaF2 is added to the raw material for the Ni-base superalloy, or to a molten metal of the raw material for the Ni-base superalloy.
  • the mold is a single crystal mold, the predetermined temperature to which the mold is preheated in the unidirectional solidification furnace is 1400 to 1550°C, and the bottom of the single crystal mold is cooled by a water-cooled chill plate.
  • the mold is a polycrystalline mold, and the predetermined temperature to which the mold is preheated in the directional solidification furnace is 1000 to 1100°C.
  • the raw material for the Ni-base superalloy is in a molten state before being poured into the mold and contains, in mass %, Cr (chromium): 2% or more and 25% or less, Co (cobalt): 0% or more and 25% or less, Mo (molybdenum): 0% or more and 8% or less, Re (rhenium): 0% or more and 10% or less, Ru (ruthenium): 0% or more and 10% or less, W (tungsten): 0% or more and 14% or less, Nb (niobium): 0% or more and 5% or less, V (vanadium): 0% or more and 3% or less, Al (aluminum): 1% or more and 10% or less, Ti (titanium): 0% or more and 10% or less, Ta (tantalum): 0% or more and 13% or less, Hf
  • the raw material for the Ni-base superalloy is in a molten state before being poured into the mold, and is, in mass%, Cr (chromium): 4% or more and 10% or less, Co (cobalt): 0% or more and 12% or less, Mo (molybdenum): 0% or more and 4% or less, Re (rhenium): 2% or more and 10% or less, Ru (ruthenium): 2% or more and 8% or less, W (tungsten): 2% or more and 8% or less, Nb (niobium): 0% or more and 2.5% or less, V (vanadium): 0% or more and 0.5% or less, Al (aluminum): 3% or more and 8% or less, Ti (titanium): 0% or more and 3% or less, Ta (tantalum): 4% or more and 10% or less, Hf (H
  • the Ni-based superalloy member of the present invention which prevents the deterioration of oxidation resistance due to Sb, comprises, in mass%, Cr (chromium): 2% or more and 25% or less, Co (cobalt): 0% or more and 25% or less, Mo (molybdenum): 0% or more and 8% or less, Re (rhenium): 0% or more and 10% or less, Ru (ruthenium): 0% or more and 10% or less, W (tungsten): 0% or more and 14% or less, Nb (niobium): 0% or more and 5% or less, V (vanadium): 0% or more and 3% or less, Al (aluminum): 1% or more and 10% or less, Ti (titanium): 0% or more and 10% or less, Ta (tantalum): 0% or more and 13% or less, Hf (Hafnium): 0% or more and 2.5% or less, C (carbon): 0% or
  • Ni-based superalloy member [13] of the present invention which prevents the deterioration of oxidation resistance due to Sb, preferably, in mass%, Cr (chromium): 4% or more and 10% or less, Co (cobalt): 0% or more and 12% or less, Mo (molybdenum): 0% or more and 4% or less, Re (rhenium): 2% or more and 10% or less, Ru (ruthenium): 2% or more and 8% or less, W (tungsten): 2% or more and 8% or less, Nb (niobium): 0% or more and 2.5% or less, V (vanadium): 0% or more and 0.5% or less, Al (aluminum): 3% or more and 8% or less, Ti (titanium): 0% or more and 3% or less, Ta (tantalum): 4% or more and 10% or less, Hf (Hafnium): 0% or more and 1% or less,
  • the Ni-base superalloy component is preferably a directionally solidified component, a single crystal cast component, or a polycrystalline solidified component.
  • the component is preferably a turbine blade or turbine vane component produced by sintering or 3D printing using a powdered Ni-base superalloy raw material satisfying the composition conditions described in [10] or [11].
  • an oxidation test piece having a diameter of 9 mm and a height of 5 mm is prepared from the Ni-base superalloy component, and in a repeated oxidation test in which one cycle is 1100°C-1h, room temperature holding-1h, no mass reduction is observed up to 100 cycles.
  • the method for producing the Ni-base superalloy of the present invention maintains the high-temperature properties (creep properties, oxidation resistance, etc.) of the Ni-base superalloy, and even if Sb is mixed in during the raw material melting process and/or a low-grade material containing a relatively high concentration of Sb of about 50 PPM is used, the deterioration of the oxidation resistance of the Ni-base superalloy due to Sb can be masked by the added element Ca.
  • Ni-base superalloy will exhibit oxidation resistance equivalent to that of a Ni-base superalloy produced using high-grade materials for Ni-base superalloys for turbine blades, which require an Sb content of 2 PPM or less. Therefore, in the production of Ni-base superalloys, it is possible to avoid limitations on the sources of raw material procurement, and to reduce material costs.
  • FIG. 1 is a cross-sectional view of the essential configuration of a melting furnace using a vacuum high-frequency induction melting furnace for casting a directionally solidified test piece or a single crystal test piece made of an Sb-containing Ni-based superalloy according to one embodiment of the present invention.
  • 1 shows Ca--Sb--O inclusions (FE-EPMA) observed in an alloy melted in a CaO crucible according to one embodiment of the present invention.
  • FIG. 2 is a perspective view showing an example of an oxidation test piece.
  • FIG. 1 is a graph showing the results of a repeated oxidation test in which one cycle is 1100° C.-1 hour and room temperature holding-1 hour.
  • compositional components and their composition ratios of the raw materials for the Ni-base superalloy used in the method for producing the Ni-base superalloy of the present invention are based on the following viewpoints:
  • the numerical ranges are defined as including the upper and lower limit values, and therefore are in principle interpreted as being equal to or greater than the lower limit value and equal to or less than the upper limit value.
  • the numerical ranges are clearly stated as being greater than the lower limit value or less than the upper limit value.
  • Cr chromium
  • the composition ratio of Cr is 2% by mass or more and 25% by mass or less.
  • composition ratio is less than 2% by mass, it is difficult to ensure high-temperature corrosion resistance and high-temperature oxidation resistance, and if it exceeds 25% by mass, harmful phases such as ⁇ phase and ⁇ phase are generated, resulting in a decrease in high-temperature strength.
  • the composition ratio of Cr is preferably 4% by mass or more and 10% by mass or less, and more preferably 8% by mass or more and 10% by mass or less.
  • Co increases the solid solubility limit in parent phases such as Al and Ta at high temperatures, disperses and precipitates fine ⁇ ' phases through heat treatment, and improves the high-temperature strength of Ni-based superalloys.
  • Co is an optional composition element, and its composition ratio is 0 mass% or more and 25 mass% or less. If the composition ratio exceeds 25 mass%, it is not preferable because the desired high-temperature strength cannot be secured.
  • Mo mobdenum
  • Mo dissolves in the matrix and contributes to increasing the high-temperature strength of Ni-based superalloys through precipitation hardening.
  • Mo is an optional composition element, and its composition ratio is 0 mass% or more and 8 mass% or less. If the composition ratio exceeds 8 mass%, harmful phases are generated and high-temperature strength decreases.
  • the composition ratio of Mo is preferably 0 mass% or more and 4 mass% or less, and more preferably 0.4 mass% or more and 2 mass% or less.
  • Re rhenium
  • Re is an optional composition element, and its composition ratio is 0 mass% or more and 10 mass% or less.
  • the composition ratio of Re is preferably 2 mass% or more and 10 mass% or less.
  • TCP phase is an abbreviation for topological close-packed phase, also known as Frank-Kasper (FK) phases, and in the case of Ni-based superalloys, it refers to the ⁇ phase or ⁇ phase.
  • Ru dissolves in the gamma phase, which is the parent phase, and improves the high-temperature strength of Ni-based superalloys through solid-solution strengthening. Ru also suppresses the precipitation of TCP phases that are generated by the addition of Re and other elements, thereby improving the high-temperature strength of Ni-based superalloys.
  • Ru is an optional composition element, and its composition ratio is preferably 0% by mass or more and 10% by mass or less, and more preferably 0% by mass or more and 8% by mass or less. If the composition ratio of Ru exceeds 10% by mass, ⁇ phase will precipitate and the high-temperature strength will decrease, which is not preferable.
  • the price of Ru in bullion is about 200 to 300 times higher than that of Ni and other elements, it is preferable to use as little Ru as possible within the range in which high-temperature strength can be improved through solid-solution strengthening, and economically, it is preferable to set the upper limit at 8% by mass.
  • W has the effect of solid solution strengthening and precipitation hardening, similar to Mo, and improves the high temperature strength of Ni-based superalloys.
  • W is an optional composition element, and its composition ratio is 0 mass% or more and 14 mass% or less. If the composition ratio exceeds 14 mass%, harmful phases are generated and the TMF properties and creep properties of the Ni-based superalloy are deteriorated.
  • the composition ratio of W is preferably 2 mass% or more and 8 mass% or less, more preferably 4 mass% or more and 7 mass% or less.
  • the TMF characteristic refers to the thermo-mechanical fatigue characteristic, and for example refers to the crack initiation life (cracks of about 2 mm depth) under multiaxial thermal fatigue conditions in a turbine blade.
  • the creep characteristic refers to the creep strength of a material, and creep tests or creep rupture tests are used.
  • the creep rupture test aims to determine the time until rupture under a certain stress, and a multiple type test machine (multiple test pieces per test machine) is often used, but a single type (single test piece per test machine) can also be used.
  • Nb niobium substitutes for the Al site of the ⁇ ' phase and contributes to precipitation strengthening. When Mo and W coexist, it improves the high-temperature strength of the Ni-based superalloy through the effects of solid solution strengthening and precipitation strengthening in the presence of Mo and W.
  • Nb is an optional composition element, and its composition ratio is 0 mass% or more and 5 mass% or less, and more preferably 0 mass% or more and 2.5 mass% or less. If the composition ratio exceeds 5 mass%, harmful phases are generated at high temperatures, and the TMF properties and creep properties are reduced.
  • V vanadium
  • V vanadium
  • V is an element that dissolves in the ⁇ ' phase and strengthens it.
  • V is an optional composition element, and its composition ratio is 0 mass% or more and 3 mass% or less, and more preferably 0 mass% or more and 0.5 mass% or less. If the composition ratio of V exceeds 3 mass%, it is not preferable because the creep properties are reduced.
  • Al combines with Ni to form an intermetallic compound represented by Ni 3 Al which constitutes the ⁇ ' phase precipitated in the ⁇ matrix phase, improving the TMF and creep properties of Ni-based superalloys, particularly at low temperatures below 1000° C.
  • the Al composition ratio is 1 mass % or more and 10 mass % or less, and more preferably 3 mass % or more and 8 mass % or less. If the composition ratio is less than 1 mass %, the amount of ⁇ ' phase is small and the required TMF and creep properties cannot be obtained, whereas if it exceeds 10 mass %, the required TMF and creep properties cannot be obtained.
  • Ti strengthens the ⁇ ' phase and improves the creep properties of Ni-based superalloys.
  • Ti is an optional composition element, and its composition ratio is 0 mass% or more and 10 mass% or less, and more preferably 0 mass% or more and 3 mass% or less. If the composition ratio exceeds 10 mass%, it is not preferable because the desired high-temperature strength cannot be secured.
  • Ta strengthens the ⁇ ' phase and improves the creep properties of Ni-based superalloys.
  • Ta is an optional element, and its composition ratio is 0 mass% or more and 13 mass% or less, and more preferably 4 mass% or more and 10 mass% or less. If the composition ratio exceeds 13 mass%, it promotes the formation of eutectic ⁇ ' phase, making solution heat treatment difficult.
  • Hf (hafnium) contributes to strengthening grain boundaries during columnar crystallization due to normal solidification and unidirectional solidification, and may improve the oxidation resistance of Ni-based superalloys and also improve the TMF properties. In addition, when Ni-based superalloys are used as single crystals, it is possible to prevent the grain boundaries from weakening even if recrystallization occurs for some reason.
  • Hf is an optional composition element, and its composition ratio is 0 mass% or more and 2.5 mass% or less, and more preferably 0 mass% or more and 1 mass% or less. If the composition ratio exceeds 2.5 mass%, the formation of harmful phases is promoted, and the TMF properties and creep properties are deteriorated.
  • C carbon segregates at the grain boundaries to improve grain boundary strength, and some of it forms carbides such as TaC and precipitates in clumps.
  • carbides such as TaC and precipitates in clumps.
  • it is recommended to add 0.08 mass% or more.
  • adding more than 0.5 mass% will form excess carbides, reducing the high-temperature strength and ductility of the Ni-based superalloy and also reducing corrosion resistance.
  • the crystallization temperature of the carbides during solidification will increase, which can lead to pinning of the carbides between dendrites and the generation of porosity, a casting defect.
  • C is an optional composition element, and its composition ratio is 0 mass% or more and 0.5 mass% or less, and more preferably 0 mass% or more and 0.05 mass% or less.
  • B boron segregates to the grain boundaries to improve grain boundary strength, and some of it forms borides such as (Cr, Ni, Mo) 3 B 2 and precipitates at the grain boundaries of the alloy.
  • borides such as (Cr, Ni, Mo) 3 B 2 and precipitates at the grain boundaries of the alloy.
  • B is an optional composition element, and its composition ratio is 0 mass% or more and 0.1 mass% or less, more preferably 0 mass% or more and 0.02 mass% or less.
  • Zr zirconium segregates at grain boundaries during columnar crystallization due to normal solidification and unidirectional solidification, and has the effect of increasing grain boundary strength, but in most cases it forms an intermetallic compound Ni 3 Zr with nickel, the main component of the alloy. This compound reduces the ductility of the alloy and has a significantly low melting point, making solution treatment of the alloy difficult, among other harmful effects. Therefore, Zr is an optional composition element, and its composition ratio is 0% by mass or more and 0.5% by mass or less, and more preferably 0% by mass or more and 0.1% by mass or less.
  • Fe replaces Ni and has the effect of improving the hot workability of Ni-based superalloys.
  • raw materials are easy to procure, which is effective in reducing material costs.
  • the above-mentioned recycled materials may contain a certain amount of Fe, but materials that contain an excessive amount are not suitable as raw materials for Ni-based superalloys.
  • Fe is an optional composition element, and its composition ratio is 0 mass% or more and 20 mass% or less, and more preferably 0 mass% or more and 5 mass% or less. If the composition ratio exceeds 20 mass%, harmful phases are generated and high-temperature strength decreases.
  • Si has the effect of improving the oxidation resistance of Ni-based superalloys.
  • Si is an optional composition element, and its composition ratio is 0 mass% or more and 1 mass% or less, and more preferably 0 mass% or more and 0.5 mass% or less. If the composition ratio exceeds 1 mass%, harmful phases are generated and high-temperature strength decreases.
  • Sb antimony
  • Sb causes a significant decrease in ductility and toughness in Ni-based superalloys after long-term heating at high temperatures of 700°C or higher for 10,000 hours or more. Therefore, in order to ensure good workability such as bending and weldability of long-term aged materials, it is necessary to first limit the Sb content in the raw materials for Ni-based superalloys to 50 PPM or less. If the content of Sb is less than 0.5 PPM, it can be treated as an unavoidable impurity, and its effect on the deterioration of the oxidation resistance of the manufactured Ni-based superalloy is within an acceptable range.
  • Sn (tin), Pb (lead), Zn (zinc) and As (arsenic) are known to be low melting point metal elements that, like Sb, cause a significant decrease in ductility and toughness of Ni-based superalloys after long-term heating at high temperatures.
  • the contents of these elements in the raw materials for Ni-based superalloys must be limited to 0.020 mass% or less of Sn, 0.010 mass% or less of Pb, 0.005 mass% or less of Zn and 0.005 mass% or less of As, respectively.
  • Ca (calcium) has the effect of fixing S (sulfur), which inhibits hot workability, as sulfide to improve the hot workability of Ni-based superalloys, so in order to obtain this effect, the raw material for Ni-based superalloys may contain Ca.
  • the Ca content exceeds 0.05 mass% (500 PPM)
  • the cleanliness of the Ni-based superalloy decreases, and the hot workability and ductility are impaired. Therefore, when Ca is added to the raw material for Ni-based superalloys, the Ca content is set to 0.05 mass% or less.
  • the upper limit of the Ca content is preferably 0.02 mass%, and more preferably 0.01 mass%.
  • the content of Ca in the raw material for the Ni-base superalloy is desirably 0.0005 mass% (5 PPM) or more, and more desirably 0.001 mass% (10 PPM) or more.
  • Ni-base superalloy components such as turbine blades and turbine vane parts using Ni-base superalloy raw materials having the above compositional components and their composition ratios.
  • Known manufacturing processes for Ni-base superalloy components include conventional casting, directional solidification, single-crystal solidification, and sintering or 3D printing using powdered Ni-base superalloy raw materials.
  • sintering or 3D printing, it is recommended to carry out the following heat treatment.
  • turbine blades and turbine vane parts made by normal casting methods can be manufactured by applying the following heat treatments. That is, the heat treatments are a series of steps: solution treatment, in which the material is held at 1200°C to 1300°C for 2 to 40 hours, followed by air cooling or cooling in an inert gas atmosphere at 150°C/min to 400°C/min; primary aging treatment, in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by air cooling or cooling in an inert gas atmosphere; and secondary aging treatment, in which the material is held at 800°C to 950°C for 10 to 30 hours, followed by air cooling or cooling in an inert gas atmosphere.
  • solution treatment in which the material is held at 1200°C to 1300°C for 2 to 40 hours, followed by air cooling or cooling in an inert gas atmosphere at 150°C/min to 400°C/min
  • primary aging treatment in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by air cooling or cooling in an
  • turbine blades and turbine vane parts made by the unidirectional solidification method can be manufactured by carrying out the following heat treatments. That is, the heat treatments are a series of steps: solution treatment, in which the material is held at 1200°C to 1300°C for 2 to 40 hours, followed by cooling in air or in an inert gas atmosphere at 200°C/min to 400°C/min; primary aging treatment, in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by cooling in air or in an inert gas atmosphere; and secondary aging treatment, in which the material is held at 800°C to 950°C for 10 to 30 hours, followed by cooling in air or in an inert gas atmosphere.
  • solution treatment in which the material is held at 1200°C to 1300°C for 2 to 40 hours, followed by cooling in air or in an inert gas atmosphere at 200°C/min to 400°C/min
  • primary aging treatment in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by cooling
  • Turbine blades and turbine vane parts made by the single crystal solidification method can be manufactured by applying the following heat treatments. That is, the heat treatments are a series of steps: solution treatment, in which the material is held at 1280°C to 1300°C for 2 to 40 hours, followed by air cooling or cooling in an inert gas atmosphere at 200°C/min to 400°C/min; primary aging treatment, in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by air cooling or cooling in an inert gas atmosphere; and secondary aging treatment, in which the material is held at 850°C to 950°C for 10 to 30 hours, followed by air cooling or cooling in an inert gas atmosphere.
  • solution treatment in which the material is held at 1280°C to 1300°C for 2 to 40 hours, followed by air cooling or cooling in an inert gas atmosphere at 200°C/min to 400°C/min
  • primary aging treatment in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by air
  • turbine blades and turbine vane parts made by sintering or 3D printing using powdered Ni-based superalloy raw materials that satisfy the above compositional conditions can be manufactured by carrying out the following heat treatments. That is, the heat treatments are a series of steps: solution treatment, in which the material is held at 1200°C to 1300°C for 2 to 40 hours, followed by cooling in air or in an inert gas atmosphere at 200°C/min to 400°C/min; primary aging treatment, in which the material is held at 1000°C to 1150°C for 2 to 5 hours, followed by cooling in air or in an inert gas atmosphere; and secondary aging treatment, in which the material is held at 850°C to 950°C for 10 to 30 hours, followed by cooling in air or in an inert gas atmosphere.
  • solution treatment in which the material is held at 1200°C to 1300°C for 2 to 40 hours, followed by cooling in air or in an inert gas atmosphere at 200°C/min to 400°C/min
  • primary aging treatment in which
  • Ni-based superalloy members such as turbine blades and turbine vane parts using a casting mold by using a Ni-based superalloy as a raw material for the Ni-based superalloy will be described.
  • the Ni-based superalloy as the raw material may be a Ni-based superalloy that contains a certain amount of Sb in advance within a range that satisfies the above-mentioned conditions, and such a material is conveniently referred to as an "Sb-containing Ni-based superalloy" in this specification.
  • the Ni-based single crystal superalloy TMS-238 used in the examples described below usually contains less than 0.5 PPM of Sb (the level of unavoidable impurities), so a predetermined amount of Sb was intentionally added to the molten metal to simulate an Sb-containing Ni-based superalloy.
  • Figure 1 is a cross-sectional view of the essential components of a melting furnace using a vacuum high-frequency induction melting furnace for casting directionally solidified test pieces or single crystal test pieces from Sb-containing Ni-based superalloys according to one embodiment of the present invention, with the vacuum exhaust system, temperature measurement device, molten raw material charging chamber, crucible tilting device, and mold lifting device not shown.
  • a vacuum high-frequency induction melting furnace 10 is installed in a melting chamber, and uses the electromagnetic induction effect of a high-frequency melting coil 14 to induce a high-current-density induced current in the metal material inside the furnace, which then heats and melts using the Joule heat generated by this induced current.
  • High-frequency induction melting furnaces have good thermal efficiency because they directly heat the metal material using electromagnetic induction, and also have the advantage of homogenizing the components because the molten metal is stirred by electromagnetic force, but they have a small refining function, so high-quality metal materials are required for melting.
  • the CaO crucible 12 is provided in the vacuum high-frequency induction melting furnace 10, and is in a vertical position into which the metal material of the Ni-based superalloy to be melted is fed from a melting material charging chamber (not shown), and the metal material is melted to become molten metal.
  • a C-1 model manufactured by Eight Ceramics Co., Ltd. was used as the CaO crucible 12.
  • the high-frequency melting coil 14 is provided on the periphery of the CaO crucible 12 in the vacuum high-frequency induction melting furnace 10, and induces an induced current with a high current density in the metal material in the CaO crucible 12.
  • the crucible tilting device (not shown) is a mechanism for tilting the CaO crucible 12 in the crucible tilting direction 16 so that the molten metal in the CaO crucible 12 can be poured from a pouring spout 28 into a mold 30 for a single crystal rod-shaped test piece.
  • the directional solidification furnace 20 has the same structure as the vacuum high-frequency induction melting furnace 10, and is provided in the mold chamber.
  • a NEV-5DSNIA model manufactured by Nisshin Giken Co., Ltd. was used as the directional solidification furnace 20.
  • the high frequency coil for mold 22 is provided on the periphery of the directional solidification furnace 20, and induces a high current density induced current in the metal material in the mold 30 for single crystal rod-shaped specimens located in the mold chamber, thereby supplying energy necessary for maintaining the molten state.
  • the graphite resistance heating element 24 is provided on the inner wall surface of the side wall of the directional solidification furnace 20, and is a heater for heating the inside of the directional solidification furnace 20.
  • the upper lining 25 is provided on the ceiling surface on the ceiling side of the directional solidification furnace 20, and is made of, for example, zirconia or alumina.
  • the side wall insulating material 26 is provided between the high frequency coil for mold 22 and the graphite resistance heating element 24, and is made of, for example, a mica sheet.
  • the upper insulating material 27 is provided between the upper lining 25 and the ceiling surface of the directional solidification furnace 20, and is made of, for example, a firebrick.
  • the pouring spout 28 is provided in the upper lining 25 and the upper insulating material 27, and is an opening for pouring the molten metal from the CaO crucible 12 in the melting chamber into the mold 30 for single crystal rod-shaped test pieces located in the mold chamber.
  • the bottom insulating material 29 is provided on the bottom surface of the directional solidification furnace 20, and is made of, for example, firebricks.
  • the mold 30 for single crystal rod-shaped test pieces is a mold for casting single crystal rod-shaped test pieces using a Ni-based superalloy.
  • FIG. 1 illustrates a mold of the type using a selector 32, a mold using a seed crystal may be used.
  • the mold base 34 is called a chill plate, and is provided with a cooling water flow path to ensure a temperature gradient necessary for crystal growth of the single crystal.
  • a self-made mold was used for the mold 30 for single crystal rod-shaped test pieces.
  • the manufacture of the mold is described in the above-mentioned Lost Wax Precision Casting Method (edited by Japan Foundry Association, published by Sangyo Tosho, 2015), and in this specification, the section on the molding method (pages 9 to 78) is particularly cited.
  • the manufacture of the mold is also described in the above-mentioned "The Superalloys Fundamentals and Applications” (written by Roger C. Reed, Cambridge University Press, 2006), and in this specification, the section on the molding method (pages 122 to 125) is particularly cited.
  • a mold lifting device (not shown) realizes the mold lifting direction 36 and ensures a cooling rate required for growing the Ni-based superalloy into a single crystal.
  • the conditions for casting a directionally solidified test piece or a single crystal test piece of an Sb-containing Ni-base superalloy using the vacuum high-frequency induction melting furnace 10 thus constructed will be described below.
  • the casting temperature of the vacuum high-frequency induction melting furnace 10 is +90 to 170°C of the solidification start temperature of the cast alloy, and the preheating temperature of the mold is set to 1400 to 1550°C.
  • the melting point of Ni is 1455°C, and the melting points of each element used as a constituent element of the Ni-based superalloy are 1495°C for Co (cobalt), 1907°C for Cr (chromium), 3440°C for W (tungsten), 660°C for Al (aluminum), 3020°C for Ta (tantalum), 3182°C for Re (rhenium), and 2334°C for Ru (ruthenium). Therefore, the temperature condition for stabilizing the molten metal in the CaO crucible 12 with the Sb-containing Ni-based superalloy completely melted is preferably 1560 to 1640°C.
  • the metallic material used was Ni-based single crystal superalloy TMS-238.
  • Table 1 shows the compositional elements and compositional ratios of TMS-238, and Table 2 shows the mechanical properties.
  • Table 1 shows the compositional elements and compositional ratios of conventional alloys CMSX-4 and MX-4/PWA1497, and Table 2 shows the mechanical properties of CMSX-4.
  • the above metal material (TMS-238) was melted by high frequency in a vacuum to cast a single crystal test piece according to the following procedure. The degree of vacuum was 6 ⁇ 10 ⁇ 2 Pa.
  • single crystal rod-shaped test pieces were also prepared by casting the alloys melted in an Al 2 O 3 crucible.
  • the metal material was Ni-based single crystal superalloy TMS-238, 10 ppm of Sb was added (injected into the molten metal), the molten metal was poured into a single crystal rod-shaped test piece mold 30 preheated to 1400 to 1550°C, and the mold 30 was pulled out of the unidirectional solidification furnace 20 at a speed of 200 mm/h, in the same manner as in the above example.
  • Glow discharge mass spectrometry confirmed that the single crystal bars of the alloy melted in the CaO crucible contained 9.5 ppm Sb, and the single crystal bars of the alloy melted in the Al2O3 crucible contained 3.8 ppm Sb. Glow discharge mass spectrometry was performed on a Thermo Scientific, Model VG9000.
  • FIG. 2 shows Ca-Sb-O inclusions (FE-EPMA: Field Emission Electron Probe Microanalyzer) observed in an alloy melted in a CaO crucible according to an embodiment of the present invention, where (A) is a backscattered electron image, (B) is O (oxygen), (C) is Ca (calcium), and (D) is Sb (antimony).
  • EPMA Electro Probe Micro Analysis
  • an electron beam is irradiated onto a sample, and the elements constituting the sample and their amounts are measured by detecting the characteristic X-rays that are generated.
  • FE-EPMA equipped with a field emission electron gun enables elemental analysis of a microscopic area of about 100 nm.
  • Data acquisition by the EBSD (Electron Back Scattered Diffraction Pattern) method was performed using a TEAM TM EDS, EDAX Division, manufacturer name, AMETEK, Inc.
  • Ca-Sb:O 1:3:2 to 1:4:3 mass ratio
  • the particle shape of the Ca-Sb-O inclusions had a particle size of 100 to 500 nm.
  • Oxidation test pieces with a diameter of 9 mm and a height of 5 mm were prepared from the single crystal rod-shaped test pieces, and a cyclic oxidation test was carried out in which one cycle consisted of 1100°C-1h, room temperature holding-1h.
  • Fig. 4 shows the results of the cyclic oxidation test. As shown in Figure 4, the mass of the alloy test piece melted in the Al2O3 crucible increased by 0.2 [mg/ cm2 ] from the first cycle compared to the initial state of the repeated oxidation test, and the mass began to decrease from the 15th cycle, resulting in a mass decrease of 3.8 [mg/ cm2 ] at 100 cycles.
  • the mass of the test piece of the alloy melted in the CaO crucible increased by 0.2 [mg/ cm2 ] from the first cycle compared to the beginning of the cyclic oxidation test, and increased by 0.3 [mg/ cm2 ] at the 100th cycle.
  • the elements constituting the oxidized test piece and their amounts were measured using EBSD. As a result, no segregation of Sb was observed at the interface between the oxide film and the base material. It is considered that the diffusion of Sb to the interface was suppressed by Ca-Sb-O inclusions.
  • a CaO crucible is used to supply Ca and O that mask the oxidation resistance deterioration caused by the impurity Sb contained in the Ni-base superalloy raw material by contacting the CaO crucible with the molten Ni-base superalloy raw material, but the present invention is not limited to this.
  • an Al2O3 crucible or an MgO crucible may be used as the crucible for melting the Ni - base superalloy raw material, and Ca and O that have the above-mentioned masking effect may be separately supplied to the Ni-base superalloy raw material or the molten Ni-base superalloy raw material.
  • a significant amount of calcium fluoride or a calcium compound may be mixed in to supply Ca (calcium) in a mass ratio of 0.33 to 100 times the content of the impurity Sb.
  • the composition elements of the calcium compound must not contain harmful elements that impair the heat resistance and oxidation resistance of the target Ni-base superalloy, such as As (arsenic) and S (sulfur).
  • a vacuum high-frequency induction melting furnace is used to cast Ni-based superalloy components by unidirectional solidification or single crystallization using Ni-based superalloys as raw materials for the Ni-based superalloy, but polycrystalline turbine parts may also be manufactured by conventional casting.
  • a polycrystalline mold is used. A polycrystalline mold does not have a selector or chill plate that is provided in a mold for single crystal rod-shaped test pieces.
  • the mold is preheated to a temperature of 800 to 1100°C.
  • the required Ca can be added by melting in a crucible made of a normal material such as an Al 2 O 3 crucible or MgO, and adding CaO granules (e.g., about 5 mm in diameter, preferably 1 to 10 mm in diameter) to the molten metal.
  • CaO granules e.g., about 5 mm in diameter, preferably 1 to 10 mm in diameter
  • the amount of CaO added is preferably 2 kg per 100 kg of molten metal as a standard value, and preferably a ratio equivalent to 0.2% to 5% by weight based on the raw material for the Ni-based superalloy. The point is to bring the molten Ni-base superalloy raw material into contact with CaO, and since excess CaO does not dissolve in the molten metal as slag, the effect on the Ca composition ratio of the directionally solidified component, single crystal cast component, or polycrystalline solidified component to be manufactured is minor.
  • CaO granules are added to the molten Ni-base superalloy raw material
  • the present invention is not limited to this, and CaO granules may be added to the Ni-base superalloy raw material before melting.
  • CaF 2 fluorite
  • the additive element Ca can mask the oxidation resistance degradation effect caused by Sb, so that even if a low-grade material for Ni-base heat-resistant alloys for boiler piping is used, it is expected that the Ni-base superalloys will exhibit oxidation resistance equivalent to that of Ni-base superalloys made using high-grade materials for conventional Ni-base superalloys for turbine blades.

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Abstract

La présente invention concerne un procédé de production d'un superalliage à base de Ni contenant du Sb empêchant la détérioration de la résistance à l'oxydation à l'aide d'un élément additif qui empêche la détérioration de la résistance à l'oxydation d'un superalliage à base de Ni due à l'élément d'impureté Sb. Un procédé de production d'un superalliage à base de Ni selon la présente invention comprend une étape dans laquelle : un matériau de départ pour un superalliage à base de Ni contenant du Sb ayant une composition spécifique est placé dans un creuset et est fondu à haute fréquence sous vide au moyen d'un four de fusion par induction à haute fréquence, tout en ajoutant du Ca dans la masse fondue du matériau de départ pour le superalliage à base de Ni en une quantité qui est nécessaire pour empêcher l'effet inhibiteur de résistance à l'oxydation du Sb ; la masse fondue est stabilisée à une température située dans la plage allant de 1 560 °C à 1 640 °C à l'intérieur du creuset pendant 10 minutes à 60 minutes dans un état dans lequel le matériau de départ pour le superalliage à base de Ni est complètement fondu ; la masse fondue est introduite dans un moule qui a été préchauffé à une température prédéfinie à l'intérieur d'un four de solidification unidirectionnelle, et le moule rempli de la masse fondue est retiré du four de fusion par induction à haute fréquence à une vitesse située dans la plage allant de 50 mm/h à 350 mm/h ; et après solidification unidirectionnelle du matériau de départ pour le superalliage à base de Ni et refroidissement du matériau solidifié de manière unidirectionnelle à la température ambiante, l'élément solidifié de manière unidirectionnelle coulé est retiré du four de solidification unidirectionnelle.
PCT/JP2023/034641 2022-10-03 2023-09-25 Procédé de production de superalliage à base de ni empêchant la détérioration de la résistance à l'oxydation due à sb, et élément en superalliage à base de ni empêchant la détérioration de la résistance à l'oxydation due à sb WO2024075560A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6299427A (ja) * 1985-10-28 1987-05-08 Mitsui Eng & Shipbuild Co Ltd 合金中の微量金属成分の含有率の調節方法
JP2013108166A (ja) * 2011-11-17 2013-06-06 Cannon-Muskegon Corp タービンブレード及びベーン用途向けのレニウムを含まない単結晶超合金
JP2013119668A (ja) * 2011-12-06 2013-06-17 Cannon-Muskegon Corp タービンブレード及びベーン用の低レニウム単結晶超合金
JP2015214744A (ja) * 2014-05-08 2015-12-03 キャノン−マスキーゴン コーポレイション 高強度単結晶超合金

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6299427A (ja) * 1985-10-28 1987-05-08 Mitsui Eng & Shipbuild Co Ltd 合金中の微量金属成分の含有率の調節方法
JP2013108166A (ja) * 2011-11-17 2013-06-06 Cannon-Muskegon Corp タービンブレード及びベーン用途向けのレニウムを含まない単結晶超合金
JP2013119668A (ja) * 2011-12-06 2013-06-17 Cannon-Muskegon Corp タービンブレード及びベーン用の低レニウム単結晶超合金
JP2015214744A (ja) * 2014-05-08 2015-12-03 キャノン−マスキーゴン コーポレイション 高強度単結晶超合金

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