WO2014157662A1 - Method for manufacturing annular molded article - Google Patents
Method for manufacturing annular molded article Download PDFInfo
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- WO2014157662A1 WO2014157662A1 PCT/JP2014/059277 JP2014059277W WO2014157662A1 WO 2014157662 A1 WO2014157662 A1 WO 2014157662A1 JP 2014059277 W JP2014059277 W JP 2014059277W WO 2014157662 A1 WO2014157662 A1 WO 2014157662A1
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- WIPO (PCT)
- Prior art keywords
- annular
- molded body
- forging
- grain size
- annular molded
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K21/00—Making hollow articles not covered by a single preceding sub-group
- B21K21/06—Shaping thick-walled hollow articles, e.g. projectiles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B5/00—Extending closed shapes of metal bands by rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
- B21H1/00—Making articles shaped as bodies of revolution
- B21H1/06—Making articles shaped as bodies of revolution rings of restricted axial length
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/28—Making machine elements wheels; discs
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/76—Making machine elements elements not mentioned in one of the preceding groups
- B21K1/761—Making machine elements elements not mentioned in one of the preceding groups rings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K3/00—Making engine or like machine parts not covered by sub-groups of B21K1/00; Making propellers or the like
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
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- 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 an annular molded body used as a processing material when producing an annular product such as a turbine disk of an aircraft engine.
- the above-described turbine disk is an annular member having a through hole, and a plurality of turbine blades are disposed on the outer peripheral side, and are configured to rotate together with the turbine blades.
- the outer peripheral portion is exposed to combustion gas and becomes a high temperature of about 600 to 700 ° C., while the temperature of the inner peripheral portion is kept relatively low, and the engine is started and stopped.
- the thermal stress is repeatedly generated inside. For this reason, excellent low cycle fatigue characteristics are required, and the outer peripheral portion is subjected to centrifugal force due to high-speed rotation around the axis at high temperature, and therefore must have high creep strength characteristics. Also, high tensile / yield strength is required.
- the annular molded body used for the turbine disk is, for example, as described in Patent Documents 1 and 2, a Ni-based superb material having excellent heat resistance. It is produced by forging a material made of an alloy and cutting the resulting annular forged body. That is, the forging is strained and the crystal grains are refined to improve the tensile strength and fatigue strength.
- a hydraulically controlled forging press capable of strict control of the forging speed is desirable, and in order to obtain the circumferential uniformity of the structure (crystal grains) in the annular formed body, the entire material is simultaneously formed. It has been recognized that application of full forging is preferred.
- ring-rolled products are more susceptible to anisotropy in mechanical properties (strength properties) than press-forged products, and are not suitable for products that require isotropic mechanical properties such as turbine disks. .
- Patent Document 3 the forging process and the ring rolling process are combined, and in the forging process, the strain ⁇ 1 in the circumferential direction and the strain ⁇ h in the height direction and the strain ratio ⁇ h / ⁇ 1 are set to appropriate values.
- annular molded body with a fine crystal grain size and a uniform shape can be obtained, for example, a large-scale annular molded body with a large thickness is obtained.
- crystal grain size of the annular molded body sometimes becomes non-uniform due to variations in operating conditions.
- the present invention has been made in view of such circumstances, and it is possible to stably and inexpensively manufacture an annular molded body having a sufficiently high mechanical strength while ensuring the uniformity of the structure. It aims at providing the manufacturing method of the cyclic
- the method for producing an annular molded body of the present invention includes a forging step of forging an alloy body to produce a disk-shaped forged body, and the forging process.
- the absolute value ⁇ 1 in the circumferential direction of the forged body is 0.3 or more
- the absolute value ⁇ h in the height direction strain of the forged body is 0.3 or more
- the ratio between the absolute values of these strains The hot forging in which ⁇ h / ⁇ 1 is in the range of 0.4 to 2.5 is performed at least twice.
- the strain rate in the forging process is 0.5 s ⁇ 1 or less.
- the strain rate exceeds 0.5 s ⁇ 1
- the crystal grain size inside the forged body is coarse due to excessive increase in the temperature inside the forged body due to processing heat (so-called heat buildup). become.
- heat buildup processing heat
- the crystal grains inside the forged body cannot be refined. Therefore, in the present invention, by setting the strain rate within the range of 0.5 s ⁇ 1 or less, the temperature difference between the surface and the inside of the forged body during forging can be reduced, and the structure can be made uniform. It becomes.
- it is preferable to set the strain rate in the forging process to 0.15 s ⁇ 1 or less.
- the strain rate is defined by the following equation.
- the absolute value ⁇ 1 of the circumferential strain is set to a large value of 0.3 or more, the proportion of the circumferential strain applied to the annular intermediate in the ring rolling process can be reduced.
- the absolute value ⁇ h of the strain in the height direction is set to a large value of 0.3 or more, it is possible to secure a sufficient amount of strain in the height direction that is difficult to impart by ring rolling.
- the processing rate in the ring rolling can be reduced, the anisotropy of the strength characteristics of the annular molded body is suppressed, the isotropic property is enhanced, and a fine crystal structure with sufficiently ensured uniformity is obtained. It is done.
- the ratio ⁇ h / ⁇ 1 indicates the directional balance of applied strain, and is an index for controlling the relative position change in the material before and after processing.
- the corresponding numerical value must be zero or close to zero due to the manufacturing method, so it is essential to suppress the anisotropy by appropriately taking the strain application ratio in the height direction in the forging process.
- ⁇ h / ⁇ 1 is less than 0.4, the effect is insufficient.
- ⁇ h / ⁇ 1 exceeds 2.5, the distribution in the height direction becomes excessive, the plastic flow becomes unstable, and the axial symmetry of the plastic flow that is indispensable for imparting uniformity is reduced. Therefore, in the present invention, by defining the ratio ⁇ h / ⁇ 1 between the absolute values of strain within the range of 0.4 to 2.5, the plastic flow is stabilized and the axial symmetry is secured, and the structure is uniform. Can be achieved.
- the method for manufacturing an annular molded body in the ring rolling step, hot rolling is performed to give an absolute value ⁇ 2 of a circumferential strain in the annular molded body of 0.5 or more, and the annular molding is performed.
- the grain size of the product region in the body may be 8 or more in terms of ASTM grain size number.
- the ring rolling process by performing hot rolling that gives an absolute value ⁇ 2 of the circumferential distortion of the annular molded body of 0.5 or more, crystals in the product region that is made into a product by machining in the annular molded body It is surely refined so that the grain size is 8 or more in terms of ASTM crystal grain size number. Accordingly, it is possible to reliably increase the mechanical strength of the product obtained from the annular molded body.
- the ASTM grain size number is determined according to the standard specified in ASTM standard E122 of American Society of Testing and Materials (American Society for Testing Materials).
- the crystal grain size difference in the product region of the annular molded body in a cross section including the axis of the annular molded body is within a range of ⁇ 2 in terms of ASTM grain size number difference. It may be there.
- this annular shaped product since the crystal grain size difference in the product region in the cross section of the annular shaped product is within the range of ⁇ 2 in terms of ASTM grain size number difference, this annular shaped product has a crystal grain size in the radial direction and the height direction. Uniformity is ensured.
- the crystal grain size of the forged body may be 7 or more in terms of ASTM grain size number.
- the crystal grain size of the forged body can be refined to 7 or more by the ASTM crystal grain size number. Therefore, the structure of the annular molded body can be refined while reducing the amount of strain applied in the next ring rolling step.
- the ratio T / H between the radial thickness T of the annular intermediate body and the height H along the axial direction of the annular intermediate body is 0.6 or more and 2 .3 after forming the annular intermediate so as to be in the range of 3 or less, ring rolling, the crystal grain size difference between a plurality of equivalent positions set uniformly in the circumferential direction on the annular molded body, ASTM grain size number The difference may be within a range of ⁇ 1.5.
- the annular intermediate is formed so that the ratio T / H between the radial thickness T and the height H of the annular intermediate is in the range of 0.6 to 2.3, and then ring-rolled.
- the crystal grain size difference between the circumferential equivalent positions in the annular molded body can be suppressed within the range of ⁇ 1.5 by the ASTM crystal grain size number difference. That is, the annular molded body obtained by molding this annular intermediate body ensures the uniformity of the crystal grain size in the circumferential direction.
- ring rolling is local processing, but unlike general partial forging, it has high continuity of processing, so the structure has a high axial symmetry, and deviation in material properties in the circumferential direction in an annular molded body. Is known to be small.
- the shape (roundness) of the molded annular molded body and the axial symmetry of the structure are further increased. it can.
- the alloy body may be a Ni-based alloy.
- the forging step is preferably performed at 950 ° C. to 1075 ° C.
- the ring rolling step is preferably performed at 900 ° C. to 1050 ° C.
- a method for producing an annular molded body capable of stably and inexpensively producing an annular molded body having a sufficiently high mechanical strength while ensuring the uniformity of the structure. Can do.
- FIG. 2 is a cross-sectional view taken along the line XX in FIG. It is a flowchart which shows the manufacturing method of the annular molded object and turbine disk which are one Embodiment of this invention. It is sectional drawing of the cyclic
- FIG. 3 is a drawing showing a tensile strength-drawing correlation diagram of an annular molded body according to an example of the present invention. It is a proof stress-drawing correlation diagram of an annular molded body according to an example of the present invention.
- the annular molded body 10 according to the present embodiment is used as a processing material for molding a turbine disk of an aircraft engine.
- the annular molded body 10 has a through hole and an annular shape centering on the axis O, and is directed radially inward from the main body 11 and the main body 11. And an outer ridge 13 projecting radially outward from the main body 11.
- the annular molded body 10 is made of a Ni-base superalloy excellent in heat resistance, and in this embodiment, is made of a Ni-base alloy Alloy718.
- the alloy composition of the Ni-based alloy Alloy 718 is as follows: Ni: 50.00 to 55.00% by mass, Cr: 17.0 to 21.0% by mass, Nb: 4.75 to 5.60% by mass, Mo; 2 0.8 to 3.3 mass%, Ti; 0.65 to 1.15 mass%, Al; 0.20 to 0.80 mass%, C; 0.01 to 0.08 mass%, the balance being Fe and inevitable It is considered as an impurity.
- the annular molded body 10 has a grain size of ASTM in the desired region (hereinafter referred to as “product region”) (not shown) that is machined into a turbine disk (product). 8 or more. 2 are cross sections including the axis O of the annular molded body 10, and these virtual planes VS1 and VS2 are at equivalent positions obtained by equally dividing the annular molded body 10 into two in the circumferential direction. Is set.
- the crystal grain size difference in the structure of the product region in the cross section of the virtual plane VS1 (or VS2) is within the range of ⁇ 2 in terms of ASTM crystal grain size number difference, and uniformity is ensured. .
- the difference in crystal grain size between equivalent positions in the circumferential direction of the annular molded body 10 that is, the difference between the crystal grain size in the virtual plane VS1 and the crystal grain size in the virtual plane VS2 is within the range of ⁇ 1.5 in terms of the ASTM crystal grain size number difference. It is said that.
- the billet is formed to have a diameter of, for example, about 7 inches to 12 inches (more specifically, 165 mm to 315 mm).
- the produced billet structure is ASTM No. It is about 6.
- Forming process S2 Next, the billet is forged so as to press in the axial direction of the billet, and a disk-shaped forged body is produced.
- the absolute strain value ⁇ 1 in the circumferential direction of the forged body is 0.3 or more
- the absolute strain in the height direction of the forged body Hot forging is carried out at least twice so that the value ⁇ h is 0.3 or more and the ratio ⁇ h / ⁇ 1 between the absolute values of these strains is in the range of 0.4 to 2.5.
- the strain rate in the hot forging in the forging step S2 is set to 0.5 s ⁇ 1 or less.
- the hot forging in the forging step S2 is performed using a hydraulically controlled forging press apparatus. This hydraulically controlled forging press apparatus can accurately adjust the strain rate during forging so as to be within the above-described range by hydraulic control.
- the strain rate in the hot forging in the forging step S2 is set to 0.01 s ⁇ 1 or more.
- the absolute value ⁇ 1 of the strain applied in the circumferential direction is set to 0.3 or more.
- the absolute value ⁇ h of the strain applied in the height direction along the axial direction of the forged body is set to 0.3 or more.
- the annular intermediate body 20 is produced by this drilling process + intermediate ring rolling step S3.
- the annular intermediate body 20 has a top surface and a bottom surface that have a substantially polygonal cross section orthogonal to the circumferential direction and extend in a direction substantially orthogonal to the axis O.
- a portion 21, an inner convex portion 22 projecting radially inward from the base portion 21, and an outer convex portion 23 projecting radially outward from the base portion 21 are provided.
- the annular intermediate 20 is subjected to ring rolling.
- the ring rolling is performed by hot rolling, and the temperature is set in the range of 900 ° C. to 1050 ° C., for example.
- the ring rolling device 30 includes a main roll 40 disposed on the outer peripheral side of the annular intermediate body 20, and a mandrel roll 50 disposed on the inner peripheral side of the annular intermediate body 20. And a pair of axial rolls 31 and 32 that are in contact with the end face in the axis O direction of the annular intermediate body 20 (in this embodiment, the upper surface and the lower surface of the base portion 21).
- the main roll 40 and the mandrel roll 50 are arranged so that the rotation axes thereof are parallel to each other, sandwich and press the annular intermediate body 20 from the inner peripheral side and the outer peripheral side, and rotate the annular intermediate body 20 in the circumferential direction. It is set as the structure rolled while making it.
- the pair of axial rolls 31 and 32 are configured to sandwich and press the annular intermediate body 20 in the axis O direction, and control the height dimension of the annular intermediate body 20.
- an accommodation recess 41 that can accommodate a part of the annular intermediate body 20 is provided on the outer peripheral portion of the main roll 40.
- the outer side of the annular intermediate body 20 is provided.
- the depth is such that the outer peripheral portions of the convex portion 23, the base portion 21 and the inner convex portion 22 can be accommodated.
- a first molding groove 42 for molding the outer protruding portion 13 of the annular molded body 10 is formed in the bottom portion 41A of the housing recess 41 on the radially inner side (right side in FIG. 6) of the main roll 40. It is formed so as to be recessed.
- channel 42 is made into the same depth as the protrusion height of the outer side protruding item
- an insertion portion 51 configured to be inserted into the housing recess 41 of the main roll 40 is provided, and the annular molded body 10 is provided on the outer peripheral surface of the insertion portion 51.
- a second forming groove 52 for forming the inner ridge portion 12 is formed so as to be recessed toward the radially inner side (left side in FIG. 6) of the mandrel roll 50.
- channel 52 is made into the same depth as the protrusion height of the inner side protruding item
- the main roll 40 and the mandrel roll 50 configured as described above operate so as to approach each other, whereby the annular intermediate body 20 is sandwiched and pressed between the main roll 40 and the mandrel roll 50. Specifically, by rotating the main roll 40 around the rotation axis of the main roll 40, the main roll 40 and the mandrel roll 50 are brought close to each other, so that an intermediate ring is formed by the frictional resistance between the main roll 40 and the main roll 40. The body 20 is rotated around the axis O.
- the mandrel roll 50 is rotatable about the rotation axis of the mandrel roll 50 and is driven to rotate by frictional resistance with the annular intermediate body 20.
- the annular intermediate body 20 is plastically deformed so as to be filled in the housing recess 41 and the first molding groove 42 of the main roll 40 and the second molding groove 52 of the mandrel roll 50, and the annular molded body 10 is molded.
- the inner ridge 12 in the annular molded body 10 is plastically deformed corresponding to the shape of the second molding groove 52.
- the outer ridge 13 is plastically deformed corresponding to the shape of the first forming groove 42.
- the annular intermediate body 20 is plastically deformed so as to extend in the circumferential direction, and the inner diameter and the outer diameter thereof are enlarged to produce the annular molded body 10 shown in FIG. It is.
- strain of the circumferential direction in the annular molded object 10 is provided. Specifically, at least one hot rolling is performed, and the absolute value ⁇ 2 of the strain is set within a range of 0.5 to 1.3 in total.
- the annular molded body 10 produced as described above is adjusted in characteristics by heat treatment, and is formed into a final shape by cutting to be a turbine disk of an aircraft engine.
- the strain rate is set to 0.5 s -1 or less in the forging step S2 in which a forged body is manufactured by forging a billet. And it can suppress that the temperature inside a forging body rises excessively by processing heat (so-called heat buildup). Therefore, the temperature difference between the surface and the inside of the forged body during forging can be reduced, and the structure of the forged body can be made uniform. In order to ensure that this effect is achieved, it is preferable to set the strain rate in the forging step S2 to 0.15 s ⁇ 1 or less.
- the absolute value ⁇ 1 of the strain in the circumferential direction is set to a large value of 0.3 or more, so the ratio of the strain amount in the circumferential direction applied to the annular intermediate body 20 in the ring rolling step S4 is reduced. be able to. Furthermore, since the absolute value ⁇ h of the strain in the height direction is set to a large value of 0.3 or more, a sufficient amount of strain in the height direction that is difficult to impart in the ring rolling step S4 can be secured.
- the processing rate in the ring rolling step S4 can be lowered, the anisotropy of the strength property of the annular molded body 10 is suppressed, the isotropic property is enhanced, and the fine crystal in which the uniformity is sufficiently secured. Organization is obtained.
- the ratio ⁇ h / ⁇ 1 between the absolute value ⁇ 1 of the strain in the circumferential direction and the absolute value ⁇ h of the strain in the height direction is 0.4 or more, a sufficient strain application ratio in the height direction is ensured. Thus, even if the subsequent ring rolling step S4 cannot sufficiently impart strain in the height direction, the uniformity of the structure can be ensured.
- the ratio ⁇ h / ⁇ 1 is 2.5 or less, the distribution in the height direction is not excessive, the plastic flow is stable, and the axial symmetry of the plastic flow that is indispensable for imparting uniformity is ensured. Can do.
- the ratio ⁇ h / ⁇ 1 between the absolute values of strain is more preferably 0.6 or more and 2.1 or less. Thereby, since the axial symmetry of plastic flow can be improved, the uniformity of the structure can be ensured more reliably.
- the absolute value ⁇ 1 of the strain applied in the circumferential direction is set to 0.3 or more, and is applied in the height direction along the axial direction of the forged body. Since the absolute value ⁇ h of the strain amount is set to 0.3 or more, it can be suppressed that the temperature inside the forged body rises due to processing heat and the crystal becomes coarse.
- the grain size of the product region in the annular molded body 10 is It is surely refined to 8 or more by ASTM grain size number. Therefore, the mechanical strength of the product obtained from the annular molded body 10 is reliably increased.
- ⁇ 2 is preferably 1.3 or less.
- the crystal grain size of the annular molded body 10 is preferably 8 or more and 13 or less in terms of ASTM grain size number. Thereby, the mechanical strength of the product obtained from the annular molded body 10 can be more reliably increased.
- the annular molded body 10 since the crystal grain size difference in the product region in the cross section including the axis O of the annular molded body 10 is within the range of ⁇ 2 in terms of the ASTM crystal grain size number difference, the annular molded body 10 has a radial direction and a high height. The uniformity of crystal grain size in the vertical direction is sufficiently secured.
- the crystal grain size of the forged body can be refined to 7 or more by the ASTM grain size number. Therefore, the structure of the annular molded body 10 can be refined while reducing the amount of strain applied in the next ring rolling step.
- annular molded object 10 can be suppressed in the range of +/- 1.5 by ASTM crystal grain size number difference. That is, in the annular molded body 10 obtained by molding the annular intermediate body 20, the uniformity of the crystal grain size in the circumferential direction is sufficiently ensured.
- the ring rolling is local processing, but unlike general partial forging, it has high continuity of processing and thus has high axial symmetry of the structure after forming, and the material properties in the circumferential direction of the annular formed body 10 are high. It is known that the deviation becomes smaller. Therefore, as in this embodiment, by setting the ratio T / H within the above-described range in the annular intermediate body 20 before ring rolling, the shape (roundness) and structure of the molded annular molded body 10 are determined. The axial symmetry of can be further increased.
- annular molded body having a sufficiently high mechanical strength while ensuring the uniformity of the structure is stably manufactured at a low cost. It becomes possible.
- the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
- the shapes of the annular molded body 10 and the annular intermediate body 20 are not limited to this embodiment, and can be appropriately changed in design in consideration of the shape of the annular product such as a turbine disk to be produced.
- the annular molded body 10 and the annular intermediate body 20 have been described as being constituted by the Ni-based alloy Alloy 718.
- the present invention is not limited to this, and other materials (for example, Waspaloy (registered trademark) (United Technology Inc.) .), Alloy 720, Co-based alloy, Fe-based alloy, etc.).
- the melt of the Ni-based alloy Alloy 718 is melted and the billet is produced by casting.
- the present invention is not limited to this, and the billet is produced by a powder molding method. It is good also as a structure which performs a ring rolling process.
- the billet may be produced by double dissolution (VIM + ESR or VIM + VAR).
- the annular formed body 10 is formed by the ring rolling step S4, before the heat treatment step S5, the annular formed body 10 is subjected to processing such as partial forging for the purpose of giving a shape and adjusting the shape dimension. May be.
- the difference between the crystal grain size in the virtual plane VS1 and the crystal grain size in the virtual plane VS2 is determined according to ASTM using equivalent positions (virtual planes VS1, VS2) obtained by equally dividing the annular molded body 10 in the circumferential direction.
- the crystal grain size number difference is assumed to be within a range of ⁇ 1.5
- the number of virtual planes to be compared is not limited to two. That is, since the annular molded body 10 is ensured equivalence in the entire circumference in the circumferential direction, not only in the above-described two divisions, but also in the crystal grain size difference between equivalent positions divided into three or more equally in the circumferential direction, The difference in ASTM grain size number is within a range of ⁇ 1.5.
- the circumferential position for setting the equivalent position is not limited.
- Example preparation First, a melt of Ni-based alloy Alloy 718 was melted. Specifically, the melting raw material was prepared so as to be in the component range of the Ni-based alloy Alloy 718 described in the above embodiment. And triple dissolution was given to this molten metal. Specifically, vacuum induction heating melting (VIM), electroslag remelting (ESR), and vacuum arc remelting (VAR) were performed to produce a cylindrical billet with a diameter of 254 mm.
- VIP vacuum induction heating melting
- ESR electroslag remelting
- VAR vacuum arc remelting
- a forging process was performed on the billet to produce a disk-shaped forged body.
- Forging was performed twice by hot forging in which the temperature of the billet was heated to 1000 ° C.
- the forging process is performed under the conditions shown in Table 1 with respect to the absolute value ⁇ 1 of the strain in the circumferential direction of the forged body, the absolute value ⁇ h of the strain in the height direction of the forged body, the ratio ⁇ h / ⁇ 1 between the absolute values of these strains, and the strain rate. It carried out in.
- the annular intermediate 20 was molded such that the ratio T / H between the thickness T and the height H was a value shown in Table 1.
- the annular intermediate 20 was subjected to ring rolling.
- the ring rolling was performed twice by hot rolling in which the temperature of the annular intermediate 20 was heated to 1000 ° C.
- the ring rolling was performed so that the sum total of the absolute value ⁇ 2 of the circumferential strain of the annular molded body 10 satisfies the conditions shown in Table 1 by these two hot rollings.
- the annular molded body 10 was subjected to heat treatment.
- As a direct aging material water-cooled after ring rolling, 718 ° C./8 hours + 621 ° C./8 hours + A. C. What gave the aging treatment of (air cooling) was produced.
- Crystal grain size measurement Using the produced annular molded body 10, the maximum crystal grain size in the product region in the cross section including the virtual planes VS1 and VS2 and the average crystal grain size around the maximum crystal grain were measured and compared. The average crystal grain size around the maximum crystal grain was the average crystal grain size of the maximum crystal grain confirmation part (excluding the maximum crystal grain). The results are shown in Table 2.
- FIG. 8 shows a tensile strength-drawing correlation diagram
- FIG. 9 shows a proof stress-drawing correlation diagram.
- Example 1 of the present invention is superior to Comparative Example 2 in all of tensile strength, 0.2% proof stress, and drawing. confirmed. That is, it was found that Example 1 of the present invention has a fine crystal structure in which the isotropy of the strength characteristics is enhanced and the uniformity is sufficiently ensured.
- annular molded body of the present invention According to the method for producing an annular molded body of the present invention, an annular molded body having a sufficiently high mechanical strength while ensuring the uniformity of the structure can be produced stably and at low cost. For this reason, the manufacturing method of the annular molded object of this invention can be used suitably for manufacture of the turbine disk of an aircraft engine, etc.
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Abstract
Description
本願は、2013年3月28日に、日本に出願された特願2013-069205号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a method for producing an annular molded body used as a processing material when producing an annular product such as a turbine disk of an aircraft engine.
This application claims priority based on Japanese Patent Application No. 2013-0669205 filed in Japan on March 28, 2013, the contents of which are incorporated herein by reference.
前述のタービンディスクにおいては、その外周部が燃焼ガスに晒されて600~700℃程度の高温になる一方、内周部の温度は比較的低く抑えられており、エンジンの起動や停止にともなって、繰り返し内部に熱応力が生じることになる。そのため、優れた低サイクル疲労特性が求められるとともに、外周部では高温下で軸周りの高速回転に起因した遠心力を受けることから、高いクリープ強度特性を合わせ持つ必要がある。また、高い引張・降伏強度も要求される。 The above-described turbine disk is an annular member having a through hole, and a plurality of turbine blades are disposed on the outer peripheral side, and are configured to rotate together with the turbine blades.
In the above-described turbine disc, the outer peripheral portion is exposed to combustion gas and becomes a high temperature of about 600 to 700 ° C., while the temperature of the inner peripheral portion is kept relatively low, and the engine is started and stopped. The thermal stress is repeatedly generated inside. For this reason, excellent low cycle fatigue characteristics are required, and the outer peripheral portion is subjected to centrifugal force due to high-speed rotation around the axis at high temperature, and therefore must have high creep strength characteristics. Also, high tensile / yield strength is required.
しかしながら、前述した大型の油圧制御鍛造プレスは、非常に高価であるばかりか世界的に見ても数が少なく、このような大型の油圧制御鍛造プレスを用いた場合、環状成形体の供給能力が制限されるとともに製品コストも高止まりしてしまうことになる。また、近年のタービンディスクの大型化傾向は、大型の油圧制御鍛造プレスを用いたとしても密閉鍛造が困難な程度にまで達しており、鍛造する環状成形体の一部領域では望ましい機械的特性が得られ難く、組織の均一性を確保し難いといった課題が生じていた。 Incidentally, in recent years, with the demand for higher output of aircraft engines, there is a demand for larger turbine disks. In order to increase the size of the annular molded body as the size of the turbine disk increases, a large hydraulic control forging press of tens of thousands of tons is required (for example, see Non-Patent Document 1).
However, the large hydraulic control forging press described above is not only very expensive but also few in the world. When such a large hydraulic control forging press is used, the supply capacity of the annular molded body is low. In addition to being limited, product costs will remain high. In addition, the trend toward larger turbine disks in recent years has reached the point where hermetic forging is difficult even when large hydraulically controlled forging presses are used. There is a problem that it is difficult to obtain and it is difficult to ensure the uniformity of the structure.
また、鍛造プレスとリング圧延とを組み合わせて環状成形体を成形する手法も考えられるが、所望の均一微細組織を得るには、前記リング圧延後にさらに最終鍛造を施す必要性が生じて、製造工程が複雑となるとともに製造コストが嵩んでしまうといった問題があった。 On the other hand, instead of forming the annular formed body by forging press, a method of forming by ring rolling can be considered. In this case, the equipment cost can be reduced and it is easy to cope with an increase in the size of the annular molded body. However, in general, ring-rolled products are more susceptible to anisotropy in mechanical properties (strength properties) than press-forged products, and are not suitable for products that require isotropic mechanical properties such as turbine disks. .
In addition, a method of forming an annular formed body by combining forging press and ring rolling is also conceivable, but in order to obtain a desired uniform microstructure, it is necessary to perform final forging after the ring rolling, and the manufacturing process However, there is a problem in that the manufacturing cost increases.
ここで、特許文献3に記載の環状成形体の製造方法について、本発明の発明者が検討した結果、鍛造体の周方向のひずみεθ1と高さ方向のひずみεhおよびこれらひずみ比εh/εθ1を適正な値に制御した熱間鍛造を複数回実施することにより、確かに結晶粒径が微細で均一な環状成形体が得られることは確認されたものの、例えば肉厚の厚い大型の環状成形体においては、操業条件のばらつき等によって、稀に環状成形体の結晶粒径が不均一となることがあった。 By the way, recently, production of high-power aircraft engines has become active, and demand for large-sized annular molded bodies has increased. Therefore, manufacturing that can stably mass-produce annular molded bodies having a uniform structure is possible. There is a need for a method.
Here, the inventors of the present invention have studied the manufacturing method of the annular molded body described in Patent Document 3, and as a result, the strain εθ1 in the circumferential direction and the strain εh in the height direction and the strain ratio εh / εθ1 are obtained. Although it has been confirmed that by carrying out hot forging controlled to an appropriate value a plurality of times, an annular molded body with a fine crystal grain size and a uniform shape can be obtained, for example, a large-scale annular molded body with a large thickness is obtained. In rare cases, the crystal grain size of the annular molded body sometimes becomes non-uniform due to variations in operating conditions.
なお、ひずみ速度は、以下の式で定義される。 In the method for producing an annular molded body of the present invention, the strain rate in the forging process is 0.5 s −1 or less. Here, when the strain rate exceeds 0.5 s −1 , the crystal grain size inside the forged body is coarse due to excessive increase in the temperature inside the forged body due to processing heat (so-called heat buildup). become. In addition, in ring rolling after forging, since the inside cannot be sufficiently distorted, the crystal grains inside the forged body cannot be refined. Therefore, in the present invention, by setting the strain rate within the range of 0.5 s −1 or less, the temperature difference between the surface and the inside of the forged body during forging can be reduced, and the structure can be made uniform. It becomes. In order to ensure that the above-described effects are achieved, it is preferable to set the strain rate in the forging process to 0.15 s −1 or less.
The strain rate is defined by the following equation.
そこで、本発明では、ひずみの絶対値同士の比εh/εθ1を0.4以上2.5以下の範囲内に規定することで、塑性流動を安定させて軸対称性を確保し、組織の均一化を図ることが可能となる。 The ratio εh / εθ1 indicates the directional balance of applied strain, and is an index for controlling the relative position change in the material before and after processing. In the subsequent ring rolling process, the corresponding numerical value must be zero or close to zero due to the manufacturing method, so it is essential to suppress the anisotropy by appropriately taking the strain application ratio in the height direction in the forging process. However, if εh / εθ1 is less than 0.4, the effect is insufficient. On the other hand, if εh / εθ1 exceeds 2.5, the distribution in the height direction becomes excessive, the plastic flow becomes unstable, and the axial symmetry of the plastic flow that is indispensable for imparting uniformity is reduced.
Therefore, in the present invention, by defining the ratio εh / εθ1 between the absolute values of strain within the range of 0.4 to 2.5, the plastic flow is stabilized and the axial symmetry is secured, and the structure is uniform. Can be achieved.
この場合、リング圧延工程において、環状成形体の周方向のひずみの絶対値εθ2を0.5以上付与する熱間圧延を行うことで、環状成形体において機械加工により製品とされる製品領域の結晶粒度が、ASTM結晶粒度番号で8以上となるように確実に微細化される。したがって、環状成形体から得られる製品の機械的強度を確実に高めることが可能となる。
なお、ASTM結晶粒度番号とは、American Society of Testing and Materials(米国材料試験協会)のASTM規格E122に規定する基準によって決定されるものである。 Here, in the method for manufacturing an annular molded body according to the present invention, in the ring rolling step, hot rolling is performed to give an absolute value εθ2 of a circumferential strain in the annular molded body of 0.5 or more, and the annular molding is performed. The grain size of the product region in the body may be 8 or more in terms of ASTM grain size number.
In this case, in the ring rolling process, by performing hot rolling that gives an absolute value εθ2 of the circumferential distortion of the annular molded body of 0.5 or more, crystals in the product region that is made into a product by machining in the annular molded body It is surely refined so that the grain size is 8 or more in terms of ASTM crystal grain size number. Accordingly, it is possible to reliably increase the mechanical strength of the product obtained from the annular molded body.
The ASTM grain size number is determined according to the standard specified in ASTM standard E122 of American Society of Testing and Materials (American Society for Testing Materials).
この場合、環状成形体の断面内の製品領域における結晶粒度差が、ASTM結晶粒度番号差で±2の範囲内とされているので、この環状成形体は、径方向及び高さ方向における結晶粒度の均一性が確保されている。 Further, in the method for producing an annular molded body according to the present invention, the crystal grain size difference in the product region of the annular molded body in a cross section including the axis of the annular molded body is within a range of ± 2 in terms of ASTM grain size number difference. It may be there.
In this case, since the crystal grain size difference in the product region in the cross section of the annular shaped product is within the range of ± 2 in terms of ASTM grain size number difference, this annular shaped product has a crystal grain size in the radial direction and the height direction. Uniformity is ensured.
この場合、鍛造工程において、前述のように高いひずみ量を付与することによって、鍛造体の結晶粒度がASTM結晶粒度番号で7以上に微細化できる。従って、次のリング圧延工程において付与するひずみ量を低減しつつも、環状成形体の組織の微細化が可能となる。 Moreover, in the manufacturing method of the annular molded body according to the present invention, in the forging step, the crystal grain size of the forged body may be 7 or more in terms of ASTM grain size number.
In this case, in the forging process, by applying a high strain amount as described above, the crystal grain size of the forged body can be refined to 7 or more by the ASTM crystal grain size number. Therefore, the structure of the annular molded body can be refined while reducing the amount of strain applied in the next ring rolling step.
この場合、環状中間体における径方向の厚さTと高さHとの比T/Hが0.6以上2.3以下の範囲内となるように環状中間体を成形した後、リング圧延することにより、環状成形体における周方向の等価位置同士の結晶粒度差をASTM結晶粒度番号差で±1.5の範囲内に抑制することができる。すなわち、この環状中間体を成形して得られる環状成形体は、周方向における結晶粒度の均一性が確保される。詳しくは、リング圧延は局部加工であるものの一般的な部分鍛造とは異なり、加工の連続性を有することから成形後の組織の軸対称性が高く、環状成形体における周方向の材料特性の偏差が小さくなることが知られている。本発明では、リング圧延前の環状中間体において前記比T/Hを前述の範囲内に設定することによって、成形された環状成形体の形状(真円度)及び組織の軸対称性を一段と高くできる。 Furthermore, in the manufacturing method of the annular molded body according to the present invention, the ratio T / H between the radial thickness T of the annular intermediate body and the height H along the axial direction of the annular intermediate body is 0.6 or more and 2 .3 after forming the annular intermediate so as to be in the range of 3 or less, ring rolling, the crystal grain size difference between a plurality of equivalent positions set uniformly in the circumferential direction on the annular molded body, ASTM grain size number The difference may be within a range of ± 1.5.
In this case, the annular intermediate is formed so that the ratio T / H between the radial thickness T and the height H of the annular intermediate is in the range of 0.6 to 2.3, and then ring-rolled. Thereby, the crystal grain size difference between the circumferential equivalent positions in the annular molded body can be suppressed within the range of ± 1.5 by the ASTM crystal grain size number difference. That is, the annular molded body obtained by molding this annular intermediate body ensures the uniformity of the crystal grain size in the circumferential direction. Specifically, ring rolling is local processing, but unlike general partial forging, it has high continuity of processing, so the structure has a high axial symmetry, and deviation in material properties in the circumferential direction in an annular molded body. Is known to be small. In the present invention, by setting the ratio T / H within the aforementioned range in the annular intermediate body before ring rolling, the shape (roundness) of the molded annular molded body and the axial symmetry of the structure are further increased. it can.
本実施形態に係る環状成形体10は、航空機用エンジンのタービンディスクを成形する加工素材として使用されるものである。 Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
The annular molded
また、環状成形体10は、耐熱性に優れたNi基超合金で構成されており、本実施形態では、Ni基合金Alloy718で構成されている。 As shown in FIGS. 1 and 2, the annular molded
Further, the annular molded
まず、Ni基合金Alloy718の溶湯を溶製する。ここで、前述したNi基合金Alloy718の成分範囲になるように、溶解原料を調製し、真空誘導加熱溶解(VIM:Vacuum Induction Melting)を行って、インゴットを製出する。次に、このインゴットをエレクトロスラグ再溶解(ESR:Electro Slag Remelting)して、再度インゴットを製出する。さらに、このインゴットを、真空アーク再溶解(VAR:Vacuum Arc Remelting)した後、熱間鍛造を行い円柱状のビレット(合金素体)を製出する。 (Melting casting process S1)
First, a melt of Ni-based alloy Alloy 718 is melted. Here, a melting raw material is prepared so as to be in the component range of the above-described Ni-based alloy Alloy 718, and vacuum induction heating melting (VIM: Vacuum Induction Melting) is performed to produce an ingot. Next, this ingot is electroslag remelted (ESR: Electro Slag Remelting) to produce the ingot again. Further, this ingot is subjected to vacuum arc remelting (VAR) and then hot forging is performed to produce a cylindrical billet (alloy body).
次に、ビレットに対して、該ビレットの軸線方向に押圧するように鍛造加工を行い、円板状の鍛造体を作製する。
この鍛造工程S2においては、ビレットの温度を、例えば950~1075℃に加熱した状態で、鍛造体の周方向のひずみの絶対値εθ1が0.3以上、鍛造体の高さ方向のひずみの絶対値εhが0.3以上、かつ、これらひずみの絶対値同士の比εh/εθ1が0.4以上2.5以下の範囲内となるように熱間鍛造を、少なくとも2回以上実施する。 (Forging process S2)
Next, the billet is forged so as to press in the axial direction of the billet, and a disk-shaped forged body is produced.
In this forging step S2, with the billet temperature heated to, for example, 950 to 1075 ° C., the absolute strain value εθ1 in the circumferential direction of the forged body is 0.3 or more, and the absolute strain in the height direction of the forged body Hot forging is carried out at least twice so that the value εh is 0.3 or more and the ratio εh / εθ1 between the absolute values of these strains is in the range of 0.4 to 2.5.
本実施形態においては、鍛造工程S2の熱間鍛造を、油圧制御鍛造プレス装置を用いて実施している。この油圧制御鍛造プレス装置は、油圧制御によって、鍛造時のひずみ速度を上述の範囲内となるように精度良く調整することが可能である。なお、本実施形態では、鍛造工程S2の熱間鍛造におけるひずみ速度を0.01s-1以上としている。 The strain rate in the hot forging in the forging step S2 is set to 0.5 s −1 or less.
In the present embodiment, the hot forging in the forging step S2 is performed using a hydraulically controlled forging press apparatus. This hydraulically controlled forging press apparatus can accurately adjust the strain rate during forging so as to be within the above-described range by hydraulic control. In the present embodiment, the strain rate in the hot forging in the forging step S2 is set to 0.01 s −1 or more.
この鍛造工程S2により、鍛造体の高さは、例えば60mm~500mm程度に調整される。このような鍛造工程によって、鍛造体にはひずみが十分に付与されて、該鍛造体の結晶粒度はASTM結晶粒度番号で7以上に微細化される。 Furthermore, in the present embodiment, the absolute value εθ1 of the strain applied in the circumferential direction is set to 0.3 or more. Moreover, the absolute value εh of the strain applied in the height direction along the axial direction of the forged body is set to 0.3 or more.
By this forging step S2, the height of the forged body is adjusted to, for example, about 60 mm to 500 mm. By such a forging process, the forged body is sufficiently strained, and the crystal grain size of the forged body is refined to 7 or more by the ASTM grain size number.
次いで、得られた鍛造体の中央部に、ウォーターカッターによって断面円形の貫通孔を形成する。さらに、貫通孔形成後に必要に応じて中間リング圧延を行う。この穿孔加工+中間リング圧延工程S3によって、環状中間体20が製出されることになる。
本実施形態では、環状中間体20は、図4に示すように、周方向に直交する断面が概略多角形状をなしており、軸線Oに対して略直交する方向に延びる上面及び下面を有する基体部21と、この基体部21から径方向内方に向けて突出した内側凸部22と、基体部21から径方向外方に向けて突出した外側凸部23と、を備えている。 (Drilling process + Intermediate ring rolling process S3)
Next, a through hole having a circular cross section is formed by a water cutter in the center of the obtained forged body. Furthermore, intermediate ring rolling is performed as necessary after forming the through holes. The annular
In the present embodiment, as shown in FIG. 4, the annular
次に、この環状中間体20に対してリング圧延を行う。なお、このリング圧延は熱間圧延で行われ、その温度は、例えば900℃~1050℃の範囲内とされている。
ここで、リング圧延装置30は、図5に示すように、環状中間体20の外周側に配設されるメインロール40と、環状中間体20の内周側に配設されるマンドレルロール50と、環状中間体20の軸線O方向端面(本実施形態では、基体部21の上面および下面)に当接される一対のアキシャルロール31、32と、を備えている。 (Ring rolling process S4)
Next, the annular intermediate 20 is subjected to ring rolling. The ring rolling is performed by hot rolling, and the temperature is set in the range of 900 ° C. to 1050 ° C., for example.
Here, as shown in FIG. 5, the
そして、このリング圧延工程S4では、環状成形体10における周方向のひずみの絶対値εθ2を0.5以上付与することとしている。詳しくは、少なくとも1回以上の熱間圧延を施して、前記ひずみの絶対値εθ2が総計で0.5以上1.3以下の範囲内に設定されるようにしている。 By carrying out the ring rolling in this way, the annular
And in this ring rolling process S4, it is supposed that 0.5 or more of absolute value (epsilon) (theta) 2 of the distortion | strain of the circumferential direction in the annular molded
前述のようにして製出された環状成形体10は、熱処理によって特性が調整されるとともに、切削加工によって最終形状に成形され、航空機用エンジンのタービンディスクとされる。 (Heat treatment step S5 / Cutting step S6)
The annular molded
例えば、環状成形体10及び環状中間体20の形状は、本実施形態に限定されるものではなく、製出するタービンディスク等の環状製品の形状を考慮して適宜設計変更することが可能である。
また、環状成形体10及び環状中間体20がNi基合金Alloy718で構成されたものとして説明したが、これに限定されることはなく、その他の材質(例えば、Waspaloy(登録商標)(United Technology Inc.)、Alloy720、Co基合金、Fe基合金等)で構成されたものであってもよい。 The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the shapes of the annular molded
In addition, the annular molded
また、ビレットを前述の三重溶解により製出する代わりに、二重溶解(VIM+ESR、又はVIM+VAR)により製出してもよい。 In addition, it has been described that the melt of the Ni-based alloy Alloy 718 is melted and the billet is produced by casting. However, the present invention is not limited to this, and the billet is produced by a powder molding method. It is good also as a structure which performs a ring rolling process.
Further, instead of producing the billet by the triple dissolution described above, the billet may be produced by double dissolution (VIM + ESR or VIM + VAR).
まず、Ni基合金Alloy718の溶湯を溶製した。詳しくは、前述の実施形態で説明したNi基合金Alloy718の成分範囲になるように溶解原料を調製した。そして、この溶湯に対して三重溶解を施した。詳しくは、真空誘導加熱溶解(VIM)、エレクトロスラグ再溶解(ESR)、真空アーク再溶解(VAR)を施して、直径φ254mmの円柱状のビレットを製出した。 (Sample preparation)
First, a melt of Ni-based alloy Alloy 718 was melted. Specifically, the melting raw material was prepared so as to be in the component range of the Ni-based alloy Alloy 718 described in the above embodiment. And triple dissolution was given to this molten metal. Specifically, vacuum induction heating melting (VIM), electroslag remelting (ESR), and vacuum arc remelting (VAR) were performed to produce a cylindrical billet with a diameter of 254 mm.
鍛造工程は、鍛造体の周方向のひずみの絶対値εθ1、鍛造体の高さ方向のひずみの絶対値εh、これらひずみの絶対値同士の比εh/εθ1、ひずみ速度について、表1に示す条件で実施した。 Next, a forging process was performed on the billet to produce a disk-shaped forged body. Forging was performed twice by hot forging in which the temperature of the billet was heated to 1000 ° C.
The forging process is performed under the conditions shown in Table 1 with respect to the absolute value εθ1 of the strain in the circumferential direction of the forged body, the absolute value εh of the strain in the height direction of the forged body, the ratio εh / εθ1 between the absolute values of these strains, and the strain rate. It carried out in.
次いで、環状成形体10に熱処理を実施した。直接時効材として、リング圧延後水冷し、718℃/8時間+621℃/8時間+A.C.(空冷)の時効処理を施したものを作製した。また、溶体化時効材として、リング圧延後970℃/1時間+W.Q.(水焼入)の溶体化処理後、718℃/8時間+A.C.(空冷)の時効処理を施したものを作製した。 Next, the annular intermediate 20 was subjected to ring rolling. The ring rolling was performed twice by hot rolling in which the temperature of the annular intermediate 20 was heated to 1000 ° C. In addition, the ring rolling was performed so that the sum total of the absolute value εθ2 of the circumferential strain of the annular molded
Next, the annular molded
作製された環状成形体10を用いて、仮想平面VS1、VS2を含む断面内の製品領域における最大結晶粒度と最大結晶粒周辺の平均結晶粒度を測定し対比した。なお、最大結晶粒周辺の平均結晶粒度は、最大結晶粒確認部(最大結晶粒を除く)の平均結晶粒度とした。結果を表2に示す。 (Crystal grain size measurement)
Using the produced annular molded
前述のように作製された環状成形体10のうち本発明例1と比較例3について、図1の仮想平面VS1、VS2を含む等価位置から周方向、高さ方向、径方向の引張試験片をそれぞれ採取し、650℃高温引張試験をそれぞれ行った。なお、試験は平行部径6.35mmのASTM E8 small size試験片を用いてASTM E21に準拠して実施し、引張強さ、耐力(0.2%耐力)及び絞りについてそれぞれ測定した。また、周方向、高さ方向、径方向の各測定値の偏差を確認するため、周方向の測定値を1(100%)とした場合の高さ方向及び径方向の割合を算出した。図8に引張強さ-絞り相関図を、図9に耐力-絞り相関図をそれぞれ示す。 (High temperature tensile property confirmation test)
Of the annular molded
一方、鍛造工程におけるひずみ速度が0.5s-1以下とした本発明例1-4においては、最大結晶粒度と最大結晶粒周辺の平均結晶粒度との差が小さく、組織が十分に均一化されていることが確認される。ひずみ速度を0.5s-1以下の範囲内とすることにより、鍛造時における鍛造体の表面と内部との温度差が小さくなり、組織の均一化を図ることができたと推測される。なお、ひずみ速度を0.15s-1以下とした本発明例1,2,4においては、さらに組織の均一化が図られている。 In Comparative Examples 1 and 2 where the strain rate in the forging process exceeds 0.5 s −1 , the maximum crystal grain size and the average crystal grain size around the maximum crystal grain are greatly different, and it is confirmed that the structure is not uniformized. Is done. It is presumed that the crystal grain size inside the forged body is locally coarsened due to excessive increase in the temperature inside the forged body due to processing heat (so-called heat buildup).
On the other hand, in Invention Example 1-4 in which the strain rate in the forging process is 0.5 s −1 or less, the difference between the maximum crystal grain size and the average crystal grain size around the maximum crystal grain is small, and the structure is sufficiently uniformized. It is confirmed that By setting the strain rate within the range of 0.5 s −1 or less, it is presumed that the temperature difference between the surface and the inside of the forged body during forging was reduced, and the structure was made uniform. In Examples 1, 2, and 4 of the present invention in which the strain rate is 0.15 s −1 or less, the structure is further uniformized.
すなわち、本発明例1は、強度特性の等方性が高められているとともに、均一性が十分に確保された微細結晶組織を有していることがわかった。 Further, as shown in FIGS. 8 and 9, as a result of the high-temperature tensile property confirmation test, Example 1 of the present invention is superior to Comparative Example 2 in all of tensile strength, 0.2% proof stress, and drawing. confirmed.
That is, it was found that Example 1 of the present invention has a fine crystal structure in which the isotropy of the strength characteristics is enhanced and the uniformity is sufficiently ensured.
20 環状中間体
H 環状中間体の軸線方向に沿う高さ
O 軸線
S2 鍛造工程
S4 リング圧延工程
T 環状中間体における径方向の厚さ
VS1 仮想平面(等価位置)
VS2 仮想平面(等価位置) DESCRIPTION OF
VS2 virtual plane (equivalent position)
Claims (8)
- 合金素体を鍛造して円板状の鍛造体を作製する鍛造工程と、前記鍛造体に貫通孔を形成してなる環状中間体をリング圧延して環状成形体を作製するリング圧延工程と、を備える環状成形体の製造方法であって、
前記鍛造工程では、ひずみ速度が0.5s-1以下、前記鍛造体の周方向のひずみの絶対値εθ1が0.3以上、前記鍛造体の高さ方向のひずみの絶対値εhが0.3以上、これらひずみの絶対値同士の比εh/εθ1が0.4以上2.5以下の範囲内となる熱間鍛造を、少なくとも2回以上行うことを特徴とする環状成形体の製造方法。 A forging step of forging an alloy body to produce a disc-shaped forged body, a ring rolling step of ring-rolling an annular intermediate formed by forming a through hole in the forged body, and producing an annular shaped body, A method for producing an annular molded body comprising:
In the forging step, the strain rate is 0.5 s −1 or less, the absolute strain value εθ1 in the circumferential direction of the forged body is 0.3 or more, and the absolute strain value εh in the height direction of the forged body is 0.3. As described above, a method for producing an annular molded body is characterized in that hot forging is performed at least twice or more so that the ratio εh / εθ1 between the absolute values of these strains is in the range of 0.4 to 2.5. - 前記環状成形体の軸線を含む断面内における該環状成形体の製品領域の結晶粒度差が、ASTM結晶粒度番号差で±2の範囲内であることを特徴とする請求項1に記載の環状成形体の製造方法。 2. The annular molding according to claim 1, wherein a crystal grain size difference in a product region of the annular molded body in a cross section including an axis of the annular molded body is within a range of ± 2 in terms of ASTM grain size number difference. Body manufacturing method.
- 前記鍛造工程では、前記鍛造体の結晶粒度をASTM結晶粒度番号で7以上とすることを特徴とする請求項1又は請求項2に記載の環状成形体の製造方法。 In the forging step, the crystal grain size of the forged body is set to 7 or more in terms of ASTM grain size number, The method for producing an annular molded body according to claim 1 or 2.
- 前記環状中間体における径方向の厚さTと該環状中間体の軸線方向に沿う高さHとの比T/Hが0.6以上2.3以下の範囲内となるように該環状中間体を成形した後、リング圧延して、前記環状成形体に周方向均等に設定した複数の等価位置同士の結晶粒度差を、ASTM結晶粒度番号差で±1.5の範囲内とすることを特徴とする請求項1から請求項3のいずれか一項に記載の環状成形体の製造方法。 The annular intermediate body has a ratio T / H between a radial thickness T of the annular intermediate body and a height H along the axial direction of the annular intermediate body in the range of 0.6 to 2.3. After forming, the ring rolling is performed, and the crystal grain size difference between a plurality of equivalent positions set uniformly in the circumferential direction in the annular molded body is set within a range of ± 1.5 in terms of ASTM crystal grain size number difference. The method for producing an annular molded body according to any one of claims 1 to 3.
- 前記リング圧延工程では、前記環状成形体における周方向のひずみの絶対値εθ2を0.5以上1.3以下付与する熱間圧延を行うことを特徴とする請求項1から請求項4のいずれか一項に記載の環状成形体の製造方法。 The said ring rolling process performs the hot rolling which provides 0.5 or more and 1.3 or less absolute value of the distortion | strain of the circumferential direction in the said annular molded object, It is any one of Claim 1 to 4 characterized by the above-mentioned. The manufacturing method of the cyclic molded object as described in one term.
- 前記合金素体はNi基合金であることを特徴とする請求項1から5のいずれか一項に記載の環状成形体の製造方法。 The method for producing an annular formed body according to any one of claims 1 to 5, wherein the alloy body is a Ni-based alloy.
- 前記鍛造工程は950℃~1075℃で行われることを特徴とする請求項6に記載の環状成形体の製造方法。 The method for producing an annular molded body according to claim 6, wherein the forging step is performed at 950 ° C to 1075 ° C.
- 前記リング圧延工程は900℃~1050℃で行われることを特徴とする請求項6又は請求項7に記載の環状成形体の製造方法。 The method for producing an annular molded body according to claim 6 or 7, wherein the ring rolling step is performed at 900 ° C to 1050 ° C.
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EP14775622.5A EP2979774B1 (en) | 2013-03-28 | 2014-03-28 | Method for manufacturing annular formed body |
ES14775622T ES2932530T3 (en) | 2013-03-28 | 2014-03-28 | Method for manufacturing ring-shaped bodies |
MX2015013639A MX2015013639A (en) | 2013-03-28 | 2014-03-28 | Method for manufacturing annular molded article. |
CN201480028783.2A CN105228771A (en) | 2013-03-28 | 2014-03-28 | The manufacture method of annular shaped body |
RU2015146287A RU2631221C2 (en) | 2013-03-28 | 2014-03-28 | Method of manufacture of annular moulded body |
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RU2703764C1 (en) * | 2019-02-21 | 2019-10-22 | Акционерное общество "Металлургический завод "Электросталь" | Method for production of large-size annular part of gas turbine engine from heat-resistant nickel-base alloy |
RU2741046C1 (en) * | 2020-07-27 | 2021-01-22 | Акционерное общество "Металлургический завод "Электросталь" | Method for production of large-size contour annular article from heat-resistant nickel-base alloy |
CN115592055A (en) * | 2022-10-10 | 2023-01-13 | 江苏保捷锻压有限公司(Cn) | Multi-step forging process for outer diameter of annular part |
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RU2699428C1 (en) * | 2018-05-28 | 2019-09-05 | Федеральное государственное автономное образовательное учреждение высшего образования "Уральский федеральный университет имени первого Президента России Б.Н. Ельцина" | Method of forging rolling rings |
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RU2631221C2 (en) | 2017-09-19 |
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ES2932530T3 (en) | 2023-01-20 |
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