EP2789708A1 - Alliage de tungstène fritté - Google Patents

Alliage de tungstène fritté Download PDF

Info

Publication number
EP2789708A1
EP2789708A1 EP12856450.7A EP12856450A EP2789708A1 EP 2789708 A1 EP2789708 A1 EP 2789708A1 EP 12856450 A EP12856450 A EP 12856450A EP 2789708 A1 EP2789708 A1 EP 2789708A1
Authority
EP
European Patent Office
Prior art keywords
tungsten alloy
flat plate
sintered
sintered tungsten
heat treatment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP12856450.7A
Other languages
German (de)
English (en)
Other versions
EP2789708A4 (fr
Inventor
Gouhei TOYOSHIMA
Noboru Uenishi
Norihito Goma
Satoshi Umemoto
Takanori KADOKURA
Tomohiro Takida
Kazunaga SAKAKIBARA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ALMT Corp
Original Assignee
ALMT Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ALMT Corp filed Critical ALMT Corp
Publication of EP2789708A1 publication Critical patent/EP2789708A1/fr
Publication of EP2789708A4 publication Critical patent/EP2789708A4/fr
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/04—Alloys based on tungsten or molybdenum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F5/006—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of flat products, e.g. sheets
    • 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
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/045—Alloys based on refractory metals
    • 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
    • C22F1/02—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working in inert or controlled atmosphere or vacuum
    • 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
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles

Definitions

  • the present invention generally relates to a sintered tungsten alloy, and particularly to a sintered tungsten alloy used as a radiation shield material in radiation medical devices, nuclear reactor-related devices and the like.
  • Japanese Patent Laying-Open No. 9-71828 discloses a tungsten-based alloy material for radiation shielding, which has a layered structure obtained by performing plastic working on a sintered body containing 85% by weight or more of tungsten as a main component, with the rest consisting of nickel and iron or copper, and flattening tungsten particles and a binder layer containing nickel, and layering these flattened layers.
  • This tungsten-based alloy material is obtained by sintering a molded body at 1470°C to form a sintered body, and rolling the obtained sintered body at a heating temperature of 1300°C such that a processing rate in total becomes about 60%, and flattening the tungsten particles and the binder layer.
  • Japanese Patent Laying-Open No. 9-235641 discloses a tungsten heavy alloy plate containing tungsten at a weight ratio of 80 to 97%, nickel at a weight ratio of 2 to 15%, and one or two or more of iron, copper and cobalt at a weight ratio of 1 to 10% in total, having a thickness of 0.3 mm or smaller, and having such a dimension that both sides are more than 200 times as large as the thickness.
  • This heavy alloy plate is obtained by mixing material powders, molding the mixture into a thin plate having a thickness of 0.35 mm or smaller by a powder rolling press, and then, sintering the molded body in the non-oxidizing atmosphere, hot-rolling and/or cold-rolling the sintered body as needed, and then, performing finish rolling for flattening and smoothing.
  • the sintered tungsten alloy containing 85% by mass or more of tungsten has the radiation shielding effect, and thus, is used as a radiation shield material in radiation medical devices, nuclear reactor-related devices and the like.
  • the sintered tungsten alloy is used in such an application, it is necessary to fabricate a flat plate-like sintered tungsten alloy having a large area of a certain degree or more.
  • the conventional sintered tungsten alloy is not sufficient in elongation as a material property. Therefore, there is a problem that a flat plate-like radiation shield member having a complex shape cannot be molded by press working or forge processing.
  • an object of the present invention is to provide a flat plate-like sintered tungsten alloy that can be molded into a complex shape by press working or forge processing.
  • a sintered tungsten alloy according to the present invention is a flat plate-like sintered tungsten alloy, containing 85% by mass or more and 98% by mass or less of tungsten, 1.4% by mass or more and 11% by mass or less of nickel, and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of iron, copper and cobalt.
  • An elongation percentage of the flat plate-like sintered tungsten alloy in a planar direction is 20% or more.
  • a thickness of the flat plate-like sintered tungsten alloy is 1.5 mm or smaller.
  • an X-ray diffraction intensity ratio of a (111) plane of a Ni-(Fe, Cu, Co) phase in a flat plate surface of the flat plate-like sintered tungsten alloy (assuming that X-ray diffraction intensities of the (111) plane, a (100) plane, a (110) plane, and a (311) plane are I(111), I(100), I(110), and I(311), respectively, the X-ray diffraction intensity ratio of the (111) plane is a value of [I(111)/ ⁇ I(111)+I(100)+I(110)+I(311) ⁇ ]) is 0.68 or more and 0.9 or less.
  • a flat plate-like sintered tungsten alloy that can be molded into a complex shape by press working or forge processing.
  • a flat plate-like sintered tungsten alloy of the present invention as an intermediate product contains 85% by mass or more and 98% by mass or less of tungsten (W), 1.4% by mass or more and 11% by mass or less of nickel (Ni), and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of iron (Fe), copper (Cu) and cobalt (Co).
  • This sintered tungsten alloy has such a structure that a plurality of flattened tungsten crystal grains extending along the extending direction of a plane of the flat plate-like sintered tungsten alloy are stacked.
  • a first cross section along the thickness direction orthogonal to the extending direction of the plane of the flat plate-like sintered tungsten alloy and a second cross section which is a cross section along the thickness direction orthogonal to the extending direction of the plane of the flat plate-like sintered tungsten alloy and which is orthogonal to the first cross section are observed to obtain a first cross section portion of a certain width and a certain thickness selected from the first cross section and a second cross section portion of a certain width and a certain thickness selected from the second cross section.
  • a ratio of an average length to an average thickness of a plurality of tungsten crystal grains which are observed at the first cross section portion and the second cross section portion and which intersect with a center line passing through a center of the certain width and extending in the direction of the certain thickness is 9 or more and 125 or less.
  • the ratio of the average length to the average thickness of the tungsten crystal grains observed as described above is 9 or more and 125 or less in the flat plate-like sintered tungsten alloy as an intermediate product configured as described above, higher strength can be obtained at high temperature than that of the conventional sintered tungsten alloy. If the ratio of the average length to the average thickness of the tungsten crystal grains observed as described above is less than 9, there is a possibility that sufficiently high strength cannot be obtained at high temperature. If the ratio of the average length to the average thickness of the tungsten crystal grains observed as described above exceeds 125, fracture may occur.
  • the average thickness of the tungsten crystal grains observed as described above is preferably 2 ⁇ m or larger and 10 ⁇ m or smaller, and the average length of the tungsten crystal grains observed as described above is preferably 30 ⁇ m or longer and 250 ⁇ m or shorter. It is difficult to set the average thickness of the tungsten crystal grains to be smaller than 2 ⁇ m or to set the average length to exceed 250 ⁇ m.
  • the average thickness of the tungsten crystal grains observed as described above is 2 ⁇ m or larger and 3 ⁇ m or smaller
  • the average length of the tungsten crystal grains observed as described above is preferably within a range of 30 ⁇ m to 250 ⁇ m, and the ratio of the average length to the average thickness is preferably 10 or more and 125 or less.
  • the average thickness of the tungsten crystal grains observed as described above exceeds 3 ⁇ m and is 6 ⁇ m or smaller
  • the average length of the tungsten crystal grains observed as described above is preferably within a range of 54 ⁇ m to 250 ⁇ m, and the ratio of the average length to the average thickness is preferably 9 or more and 84 or less, in order to obtain sufficiently high strength at high temperature.
  • the average thickness of the tungsten crystal grains observed as described above exceeds 6 ⁇ m and is 10 ⁇ m or smaller
  • the average length of the tungsten crystal grains observed as described above is preferably within a range of 90 ⁇ m to 250 ⁇ m, and the ratio of the average length to the average thickness is preferably 9 or more and 42 or less, in order to obtain sufficiently high strength at high temperature.
  • the tungsten crystal grain in the planar direction of the flat plate-like sintered tungsten alloy has various shapes such as a substantially circular shape, a substantially oval shape, a substantially square shape, a substantially rectangular shape, and an indefinite shape.
  • the flat plate-like sintered tungsten alloy of the present invention as an intermediate product is manufactured through (1) materials preparing step, (2) mixing step, (3) molding step, (4) sintering step, (5) distortion introducing step, (6) heat treatment step, and (7) hot-rolling step.
  • a method for manufacturing the flat plate-like sintered tungsten alloy of the present invention as an intermediate product is a method for manufacturing a sintered tungsten alloy containing 85% by mass or more and 98% by mass or less of tungsten, 1.4% by mass or more and 11% by mass or less of nickel, and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of iron, copper and cobalt, characterized in that a distortion is introduced into a sintered body and heat treatment is performed on the sintered body having the distortion introduced therein, and then, the sintered body is hot-rolled at a rolling processing rate of 60% or more.
  • the flat plate-like sintered tungsten alloy thus manufactured can have such a structure that the ratio of the average length to the average thickness of the tungsten crystal grains observed as described above is 9 or more and 125 or less, and higher strength can be obtained at high temperature than that of the conventional sintered tungsten alloy.
  • a certain level of distortion is provided to a sintered tungsten alloy (sintered body) that has tungsten crystal grains with a grain size of 30 to 50 ⁇ m fabricated in accordance with a conventionally known manufacturing method (a mixing step, a molding step and a sintering step of material powders), and then, a certain level of heat treatment is performed.
  • the grain size of the tungsten crystal grain in the sintered tungsten alloy can be decreased to a certain value or smaller (5 to 20 ⁇ m).
  • the sintered body is hot-rolled at a rolling processing rate of 60% or more.
  • the thickness of the tungsten crystal grain can be decreased to a certain value or smaller and the length of the tungsten crystal grain can be increased to a certain value or larger, and thus, there can be obtained a sintered tungsten alloy having such a structure that a plurality of flattened tungsten crystal grains extending in the planar direction of the flat plate-like sintered tungsten alloy are stacked. As a result, higher strength can be obtained at high temperature than that of the conventional sintered tungsten alloy.
  • the flat plate-like sintered tungsten alloy according to the present invention contains 85% by mass or more and 98% by mass or less of tungsten, 1.4% by mass or more and 11% by mass or less of nickel, and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of iron, copper and cobalt.
  • An elongation percentage of the flat plate-like sintered tungsten alloy in the planar direction is 20% or more.
  • the flat plate-like sintered tungsten alloy in the planar direction is 20% or more in the flat plate-like sintered tungsten alloy configured as described above, the flat plate-like sintered tungsten alloy can be molded into a complex shape by press working or forge processing.
  • the elongation percentage of the flat plate-like sintered tungsten alloy in the planar direction is less than 20%, there is no difference in elongation percentage from the conventional sintered tungsten alloy and there is a possibility that the flat plate-like sintered tungsten alloy cannot be molded into a complex shape by press working or forge processing.
  • An upper limit value of the elongation percentage of the flat plate-like sintered tungsten alloy in the planar direction is 45%. It is difficult to obtain a flat plate-like sintered tungsten alloy in which the elongation percentage of the flat plate-like sintered tungsten alloy in the planar direction exceeds 45%.
  • the flat plate-like sintered tungsten alloy according to the present invention is manufactured through (1) materials preparing step, (2) mixing step, (3) molding step, (4) sintering step, (5) distortion introducing step, (6) heat treatment step, (7) hot-rolling step, and (8) heat treatment step.
  • the method for manufacturing the flat plate-like sintered tungsten alloy according to the present invention is a method for manufacturing a sintered tungsten alloy containing 85% by mass or more and 98% by mass or less of tungsten, 1.4% by mass or more and 11% by mass or less of nickel, and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of iron, copper and cobalt, characterized in that a distortion is introduced into a sintered body and heat treatment is performed on the sintered body having the distortion introduced therein, and then, the sintered body is hot-rolled at a rolling processing rate of 60% or more and further heat treatment is performed on the hot-rolled sintered body.
  • the elongation percentage of the flat plate-like sintered tungsten alloy in the planar direction can be 20% or more, and the flat plate-like sintered tungsten alloy can be molded into a complex shape by press working or forge processing.
  • the flat plate-like sintered tungsten alloy according to the present invention is obtained by performing further heat treatment on the flat plate-like sintered tungsten alloy of the present invention as an intermediate product.
  • the flat plate-like sintered tungsten alloy does not have the structure of the sintered tungsten alloy of the present invention as an intermediate product, but has a structure very close to a structure of the conventional sintered tungsten alloy immediately after sintering.
  • the sintered tungsten alloy according to the present invention is returned through the structure of the sintered tungsten alloy of the present invention as an intermediate product to the structure very close to the structure of the conventional sintered tungsten alloy.
  • the thickness of the flat plate-like sintered tungsten alloy according to the present invention is 1.5 mm or smaller.
  • an X-ray diffraction intensity ratio of a (111) plane of a Ni-(Fe, Cu, Co) phase in a flat plate surface of the flat plate-like sintered tungsten alloy (assuming that X-ray diffraction intensities of the (111) plane, a (100) plane, a (110) plane, and a (311) plane are I(111), I(100), I(110), and I(311), respectively, the X-ray diffraction intensity ratio of the (111) plane is a value of [I(111)/ ⁇ I(111)+I(100)+I(110)+I(311) ⁇ ]) is 0.68 or more and 0.9 or less.
  • the (111) plane serving as a sliding plane of an FCC (face-centered cubic) structure is oriented in parallel to the planar direction.
  • This has an influence even after (8) heat treatment step described above, and the orientation of the (111) plane remains in the flat plate-like sintered tungsten alloy as a final product. Since the sliding plane of the binder plane is oriented in parallel to the planar direction as described above, it can become easy for the tungsten crystal grains to slide in the binder component. By heat treatment, almost all defects present in the sintered tungsten alloy can be eliminated and elongation of the sintered tungsten alloy in the planar direction can be further enhanced.
  • the method for manufacturing the sintered tungsten alloy according to the present invention a distortion is introduced into the sintered body and heat treatment is performed on the sintered body having the distortion introduced therein, and then, hot-rolling processing is performed. Therefore, the sintered body can be hot-rolled at a rolling processing rate of 60% or more. As a result, the flat plate-like sintered tungsten alloy having a thickness of 1.5 mm or smaller can be formed. Therefore, the manufacturing method of the present invention is particularly advantageous to obtain a thin flat plate and the manufacturing cost can be reduced.
  • the obtained flat plate-like sintered tungsten alloy can be further thinned by rolling processing and the like.
  • a lower limit value of the thickness of the flat plate-like sintered tungsten alloy according to the present invention is 0.05 mm. It is difficult to set the thickness of the flat plate-like sintered tungsten alloy to be smaller than 0.05 mm.
  • the sintered tungsten alloy according to the present invention may contain elements other than nickel (Ni), iron (Fe), copper (Cu), and cobalt (Co), and may contain, for example, 0% by mass or more and 2% by mass or less of an element such as manganese (Mn), molybdenum (Mo), silicon (Si), rhenium (Re), chromium (Cr), titanium (Ti), vanadium (V), niobium (Nb), and tantalum (Ta), to such an extent that the function and effect of the present invention are not impaired.
  • an element such as manganese (Mn), molybdenum (Mo), silicon (Si), rhenium (Re), chromium (Cr), titanium (Ti), vanadium (V), niobium (Nb), and tantalum (Ta), to such an extent that the function and effect of the present invention are not impaired.
  • a tungsten powder, a nickel powder, and a metal powder of at least one substance selected from the group consisting of iron, copper and cobalt are prepared.
  • the materials are prepared to contain the tungsten powder at a blending ratio of 85% by mass or more and 98% by mass or less, nickel at a blending ratio of 1.4% by mass or more and 11% by mass or less, and the metal powder of at least one substance selected from the group consisting of iron, copper and cobalt at a blending ratio of 0.6% by mass or more and 6% by mass or less.
  • the strength of the obtained sintered tungsten alloy may be insufficient. If the blending ratio of the tungsten powder exceeds 98% by mass, the binder component may be insufficient and fracture may occur in the obtained sintered tungsten alloy during the rolling step.
  • the blending ratio of the nickel powder is less than 1.4% by mass, fracture may occur in the obtained sintered tungsten alloy during the rolling step. If the blending ratio of the nickel powder exceeds 11% by mass, the strength of the obtained sintered tungsten alloy may be insufficient.
  • Iron, copper and cobalt serve as a sintering aid. If the blending ratio of the metal powder of at least one substance selected from the group consisting of iron, copper and cobalt is less than 0.6% by mass, the dense sintered body cannot be obtained, and thus, fracture may occur in the obtained sintered tungsten alloy during the rolling step. If the blending ratio of the aforementioned metal powder exceeds 6% by mass, the binder component is excessively cured, and thus, the toughness of the obtained sintered tungsten alloy itself may be reduced.
  • the average grain size of each of the tungsten powder, the nickel powder and the aforementioned metal powder is preferably 1 ⁇ m or larger and 10 ⁇ m or smaller. If the average grain size of each of these powders is smaller than 1 ⁇ m, the manufacturing cost may increase. If the average grain size of each of these powders exceeds 10 ⁇ m, a gap is likely to be formed in the obtained sintered tungsten alloy, and thus, fracture may occur in the sintered tungsten alloy during the rolling step.
  • the tungsten powder, the nickel powder, and the metal powder of at least one substance selected from the group consisting of iron, copper and cobalt, which were prepared as described above, are mixed to obtain a mixture.
  • Mixing can be performed by using a Lodige mixer, an attritor, a ball mill or the like.
  • a solvent and a binder may be added to the material powders.
  • Camphor, Merball, stearic acid, paraffin or the like can be used as the binder.
  • Ethanol, methanol, acetone or the like can be used as the solvent.
  • Pressure is applied to the mixture obtained as described above and the mixture is molded to obtain a molded body.
  • the pressure is applied to the mixture by using cold isotropic pressure press (CIP), dry CIP, mechanical press or the like.
  • CIP cold isotropic pressure press
  • the pressure applied at the time of molding is preferably 49 MPa or higher and lower than 294 MPa. If the pressure is lower than 49 MPa, there is a possibility that the molded body cannot be obtained. Even if the molded body can be obtained, the molded body may be broken during handling and the subsequent steps. Even if the pressure is 294 MPa or higher, no problem arises, while the function for obtaining the molded body is not enhanced.
  • the molded body obtained as described above is sintered to obtain a sintered body.
  • the atmosphere of a hydrogen gas, vacuum or an inert gas can be used as the atmosphere for sintering the molded body.
  • a batch furnace, a continuous pressure furnace or the like can be used as a sintering furnace that houses the molded body.
  • the sintering temperature is preferably 1200°C or higher and 1550°C or lower. If the sintering temperature is lower than 1200°C, the dense sintered body cannot be obtained, and thus, fracture may occur in the obtained sintered tungsten alloy during the rolling step. If the sintering temperature exceeds 1550°C, the sintered body may melt.
  • the sintering time is preferably 10 minutes or longer and 300 minutes or shorter when the sintering temperature is maximum. If the sintering time is shorter than 10 minutes, the dense sintered body cannot be obtained, and thus, fracture may occur in the obtained sintered tungsten alloy during the rolling step. If the sintering time exceeds 300 minutes, the tungsten crystal grains become too coarse, and thus, there is a possibility that the tungsten crystal grains cannot become sufficiently fine grains during the subsequent steps.
  • the molding step and the sintering step may be simultaneously performed by using hot isotropic pressure press (HIP).
  • HIP hot isotropic pressure press
  • an inert gas such as a nitrogen gas and an argon gas can be used as the atmosphere.
  • the pressure is preferably 500 MPa or higher and 1500 MPa or lower. If the pressure is lower than 500 MPa, the dense sintered body cannot be obtained, and thus, fracture may occur in the obtained sintered tungsten alloy during the rolling step. Even if the pressure exceeds 1500 MPa, no problem arises, while the function for obtaining the sintered body is not enhanced.
  • the temperature is preferably 1200°C or higher and 1550°C or lower. If the temperature is lower than 1200°C, the dense sintered body cannot be obtained, and thus, fracture may occur in the obtained sintered tungsten alloy during the rolling step. If the temperature exceeds 1550°C, the sintered body may melt.
  • a distortion is introduced into the sintered body (sintered tungsten alloy) obtained as described above.
  • the distortion is preferably introduced into the sintered body by, for example, deforming the flat plate-like sintered body in the thickness direction at a deformation rate of 20% or more and 50% or less. If the deformation rate is less than 20%, an amount of distortion introduced into the sintered body is insufficient, and thus, there is a possibility that fine crystal grains cannot be formed even if heat treatment is performed in the subsequent step. If the deformation rate exceeds 50%, fracture may occur in the sintered body.
  • the temperature of the sintered body at the time of introduction of the distortion is preferably 0°C or higher and 600°C or lower. If the temperature is lower than 0°C, the sintered body becomes hard, and thus, fracture may occur. If the temperature exceeds 600°C, the introduced distortion is released, and thus, there is a possibility that fine crystal grains cannot be formed even if heat treatment is performed in the subsequent step.
  • a method for introducing the distortion into the sintered body can include deforming the sintered body by forge processing, mechanical press working, cold-rolling processing or the like.
  • Heat treatment is performed on the sintered body (sintered tungsten alloy) having the distortion introduced therein.
  • the distortion introduced into the sintered body is recovered to an appropriate level and the tungsten crystal grains become fine grains.
  • the atmosphere of vacuum, a hydrogen gas, a nitrogen gas, an argon gas, or a carbon monoxide gas can be used as the atmosphere for performing heat treatment on the sintered body.
  • the heat treatment temperature is preferably 900°C or higher and 1400°C or lower. If the heat treatment temperature is lower than 900°C, recovery of the distortion is insufficient and the tungsten crystal grains do not become fine grains, and thus, fracture may occur in the sintered body during the subsequent hot-rolling step. If the heat treatment temperature exceeds 1400°C, the distortion is completely recovered and the tungsten crystal grains become coarse, and thus, fracture may occur in the sintered body during the subsequent hot-rolling step.
  • the heat treatment time is preferably 20 minutes or longer and 5 hours or shorter. If the heat treatment time is shorter than 20 minutes, recovery of the distortion is insufficient and the tungsten crystal grains do not become fine grains, and thus, fracture may occur in the sintered body during the subsequent hot-rolling step. If the heat treatment time exceeds 5 hours, the distortion is completely recovered and the tungsten crystal grains become coarse, and thus, fracture may occur in the sintered body during the subsequent hot-rolling step.
  • the average grain size of the tungsten crystal grains in the sintered tungsten alloy after heat treatment is preferably 5 ⁇ m or larger and 20 ⁇ m or smaller. It is difficult to set the average grain size of the tungsten crystal grains to be smaller than 5 ⁇ m. If the average grain size of the tungsten crystal grains exceeds 20 ⁇ m, fracture may occur in the sintered body during the subsequent hot-rolling step.
  • Rolling processing is performed on the sintered body (sintered tungsten alloy) subjected to heat treatment as described above at a rolling processing rate of 60% or more, with the sintered body heated.
  • the atmosphere of a hydrogen gas, a nitrogen gas, an argon gas or the like can be used as the atmosphere for heating the sintered body.
  • the rolling processing temperature is preferably 800°C or higher and 1400°C or lower. If the rolling processing temperature is lower than 800°C, a large load is applied to a rolling machine, and thus, rolling processing cannot be performed or fracture may occur in the sintered body. If the rolling processing temperature exceeds 1400°C, the tungsten crystal grains become coarse, and thus, fracture may occur in the sintered body when rolling processing is performed.
  • the rolling processing rate of one rolling is preferably 5% or more and 30% or less. If the rolling processing rate of one rolling is less than 5%, the number of rolling for achieving the rolling processing rate of 60% or more in total increases and the manufacturing cost increases. If the rolling processing rate of one rolling exceeds 30%, a large load is applied to the rolling machine, and thus, rolling processing cannot be performed or fracture may occur in the sintered body.
  • the rolling processing rate in total is preferably 60% or more and 95% or less. If the rolling processing rate in total is less than 60%, the tungsten crystal grains do not become flattened particles, and thus, there is a possibility that sufficiently high strength of the sintered tungsten alloy at high temperature is not obtained. If the rolling processing rate in total exceeds 95%, fracture may occur in the sintered body due to rolling processing.
  • (5) distortion introducing step and (6) heat treatment step are performed and then (7) hot-rolling step is performed on the sintered body (sintered tungsten alloy) obtained in (4) sintering step.
  • rolling can be performed at a rolling processing rate of 60% or more and 95% or less and the flat plate-like sintered tungsten alloy as an intermediate product having a thickness of 1.5 mm or smaller can be manufactured.
  • a lower limit value of the thickness of the sintered tungsten alloy of the present invention as an intermediate product is 0.5 mm. It is difficult to obtain the sintered tungsten alloy having a thickness of smaller than 0.5 mm, even when (5) distortion introducing step and (6) heat treatment step are performed and then (7) hot-rolling step is performed.
  • the atmosphere of vacuum, a hydrogen gas or an inert gas can be used as the atmosphere for performing heat treatment on the sintered body subjected to hot-rolling processing.
  • a batch furnace or a continuous pressure furnace can be used as a furnace for performing heat treatment.
  • the heat treatment temperature is preferably 1300°C or higher and 1550°C or lower. If the heat treatment temperature is lower than 1300°C, the tungsten crystal grains become coarse insufficiently, and thus, there is a possibility that the processability in cold working is not enhanced. If the heat treatment temperature exceeds 1550°C, the sintered body may melt.
  • the heat treatment time is preferably 10 minutes or longer and 5 hours or shorter. If the heat treatment time is shorter than 10 minutes, the tungsten crystal grains become coarse insufficiently, and thus, there is a possibility that the processability in cold working is not enhanced. If the heat treatment time exceeds 5 hours, the tungsten crystal grains become coarse and the processability decreases, and thus, fracture may occur in the sintered body when the sintered body is processed into a complex shape.
  • the average grain size of the tungsten crystal grains in the sintered tungsten alloy after heat treatment is preferably 20 ⁇ m or larger and 60 ⁇ m or smaller. If the average grain size of the tungsten crystal grains is smaller than 20 ⁇ m, the effect of heat treatment is insufficient and high elongation percentage is not obtained, and thus, there is a possibility that the processability in cold working is not enhanced. If the average grain size of the tungsten crystal grains exceeds 60 ⁇ m, the tungsten crystal grains become coarse and the processability decreases, and thus, fracture may occur in the sintered body when the sintered body is processed into a complex shape.
  • the aforementioned flat plate-like sintered tungsten alloy of the present invention as an intermediate product was fabricated. Namely, the aforementioned steps (1) to (7) were performed to fabricate the flat plate-like sintered tungsten alloy.
  • the obtained molded body had a dimension of 176 mm ⁇ 176 mmx8.2 mm.
  • the molded body obtained as described above was sintered in the hydrogen gas atmosphere furnace at a temperature of 1460°C for 80 minutes to obtain a sintered body ((4) sintering step).
  • the obtained sintered body had a dimension of 150 mm ⁇ 150 mmx7 mm.
  • Fig. 1 shows an optical microscope photograph obtained by observing a cross section of the flat plate-like sintered tungsten alloy obtained as described above.
  • the obtained flat plate-like sintered tungsten alloy was deformed in the thickness direction at a temperature of 25°C at a deformation rate of 30% to introduce a distortion into the sintered tungsten alloy ((5) distortion introducing step).
  • the flat plate-like sintered tungsten alloy having the distortion introduced therein had a dimension of 177 mm ⁇ 177 mm ⁇ 5 mm.
  • Heat treatment was performed on the flat plate-like sintered tungsten alloy having the distortion introduced therein, in the vacuum furnace at a temperature of 1200°C for 3 hours ((6) heat treatment step).
  • Fig. 2 shows an optical microscope photograph obtained by observing a cross section of the flat plate-like sintered tungsten alloy obtained as described above. As shown in Fig. 2 , it can be seen that the tungsten crystal grains have become fine grains and the average grain size is approximately 10 ⁇ m.
  • a sample of the flat plate-like sintered tungsten alloy subjected to heat treatment was heated in the hydrogen gas atmosphere furnace to a temperature of 1100°C, and then, the sample was taken out from the furnace and rolling processing was immediately performed at a rolling processing rate of approximately 10%, and the rolling processing was repeated until the rolling processing rate in total reached 80% ((7) hot-rolling step).
  • the flat plate-like sintered tungsten alloy after hot-rolling processing had a dimension of 100 mm ⁇ 1070 mm ⁇ 1 mm.
  • Heat treatment was performed on the obtained flat plate-like sintered tungsten alloy as an intermediate product in the vacuum furnace at a temperature of 1450°C for 60 minutes ((8) heat treatment step).
  • Fig. 3 shows an optical microscope photograph obtained by observing a cross section of the flat plate-like sintered tungsten alloy as a final product obtained as described above. As shown in Fig. 3 , it can be seen that the tungsten crystal grains have become coarse and the average grain size is approximately 35 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment temperature was 1300°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using an optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 21 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment temperature was 1550°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 43 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment time was 10 minutes in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 25 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment time was 3 hours in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 39 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment time was 5 hours in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 57 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.1 mm was fabricated similarly to Example 1, except that a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 20% in the distortion introducing step and the heat treatment temperature was 1500°C in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 19 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 39 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.9 mm was fabricated similarly to Example 1, except that a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 40% in the distortion introducing step and the heat treatment temperature was 1500°C in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 10 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 38 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.7 mm was fabricated similarly to Example 1, except that a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step and the heat treatment temperature was 1500°C in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 39 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 2.0 mm was fabricated similarly to Example 1, except that rolling processing was performed until the rolling processing rate in total reached 60% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 39 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.5 mm was fabricated similarly to Example 1, except that rolling processing was performed until the rolling processing rate in total reached 70% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 36 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.7 mm was fabricated similarly to Example 1, except that rolling processing was performed until the rolling processing rate in total reached 85% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 37 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that rolling processing was performed until the rolling processing rate in total reached 90% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 37 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that the thickness of a sintered body obtained in the sintering step was 14 mm and rolling processing was performed until the rolling processing rate in total reached 95% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 39 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that the thickness of a sintered body obtained in the sintering step was 20 mm, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 95% in the hot-rolling step, and the heat treatment temperature was 1300°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 23 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that the thickness of a sintered body obtained in the sintering step was 20 mm, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 95% in the hot-rolling step, and the heat treatment temperature was 1450°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 37 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that the thickness of a sintered body obtained in the sintering step was 20 mm, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 95% in the hot-rolling step, and the heat treatment temperature was 1550°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 47 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 2.2 mm was fabricated similarly to Example 1, except that a tungsten powder having an average grain size of 1 ⁇ m was used and a copper powder was used instead of the iron powder in the materials preparing step, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 20% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 60% in the hot-rolling step, and the heat treatment temperature was 1300°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 19 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 21 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.7 mm was fabricated similarly to Example 1, except that a tungsten powder having an average grain size of 5 ⁇ m was used and a copper powder was used instead of the iron powder in the materials preparing step, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 20% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 70% in the hot-rolling step, and the heat treatment temperature was 1300°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 19 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 23 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.7 mm was fabricated similarly to Example 1, except that a tungsten powder having an average grain size of 10 ⁇ m was used and a copper powder was used instead of the iron powder in the materials preparing step, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 20% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 90% in the hot-rolling step, and the heat treatment temperature was 1300°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 19 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 22 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that preparation was made in the materials preparing step to contain a tungsten powder at a blending ratio of 85% by mass, a nickel powder at a blending ratio of 10.5% by mass, and an iron powder at a blending ratio of 4.5% by mass, rolling processing was performed until the rolling processing rate in total reached 90% in the hot-rolling step, and the heat treatment temperature was 1300°C and the heat treatment time was 3 hours in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 9 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 24 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that preparation was made in the materials preparing step to contain a tungsten powder at a blending ratio of 90% by mass, a nickel powder at a blending ratio of 7% by mass, and an iron powder at a blending ratio of 3% by mass, rolling processing was performed until the rolling processing rate in total reached 90% in the hot-rolling step, and the heat treatment temperature was 1300°C and the heat treatment time was 3 hours in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 10 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 24 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that preparation was made in the materials preparing step to contain a tungsten powder at a blending ratio of 98% by mass, a nickel powder at a blending ratio of 1.4% by mass, and an iron powder at a blending ratio of 0.6% by mass, rolling processing was performed until the rolling processing rate in total reached 90% in the hot-rolling step, and the heat treatment temperature was 1300°C and the heat treatment time was 3 hours in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 10 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 26 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that a nickel powder having an average grain size of 1 ⁇ m was used and a cobalt powder was used instead of the iron powder in the materials preparing step, and the heat treatment temperature was 1300°C and the heat treatment time was 5 hours in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 11 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 28 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that a nickel powder having an average grain size of 5 ⁇ m was used and a cobalt powder was used instead of the iron powder in the materials preparing step, and the heat treatment temperature was 1300°C and the heat treatment time was 5 hours in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 10 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 30 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that a nickel powder having an average grain size of 10 ⁇ m was used and a cobalt powder was used instead of the iron powder in the materials preparing step, and the heat treatment temperature was 1300°C and the heat treatment time was 5 hours in the heat treatment step after the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 10 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 27 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that an iron powder having an average grain size of 1 ⁇ m was used in the materials preparing step, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, and rolling processing was performed until the rolling processing rate in total reached 60% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 32 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that an iron powder having an average grain size of 5 ⁇ m was used in the materials preparing step, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, and rolling processing was performed until the rolling processing rate in total reached 60% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 35 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that an iron powder having an average grain size of 10 ⁇ m was used in the materials preparing step, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, and rolling processing was performed until the rolling processing rate in total reached 60% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 33 ⁇ m.
  • a conventional sintered tungsten alloy fabricated by performing the aforementioned steps (1) to (4) was processed to have a thickness of 1 mm by grinding and polishing.
  • Fig. 4 shows an optical microscope photograph obtained by observing a cross section of the flat plate-like sintered tungsten alloy obtained as described above.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment temperature was 1200°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 18 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment time was 6 minutes in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 17 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 1.0 mm was fabricated similarly to Example 1, except that the heat treatment time was 6 hours in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 64 ⁇ m.
  • Example 2 An attempt was made to fabricate a flat plate-like sintered tungsten alloy similarly to Example 1, except that a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 17% in the distortion introducing step and the heat treatment temperature was 1500°C in the heat treatment step after the hot-rolling step. However, fracture occurred after the hot-rolling step.
  • Example 1 a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 24.3 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 2.5 mm was fabricated similarly to Example 1, except that rolling processing was performed until the rolling processing rate in total reached 50% in the hot-rolling step.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 37 ⁇ m.
  • a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm was fabricated similarly to Example 1, except that the thickness of a sintered body obtained in the sintering step was 20 mm, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 95% in the hot-rolling step, and the heat treatment temperature was 1200°C in the heat treatment step after the hot-rolling step. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • a cross section of the flat plate-like sintered tungsten alloy as a final product was observed by using the optical microscope.
  • the average grain size of the tungsten crystal grains was approximately 17 ⁇ m.
  • Example 2 An attempt was made to fabricate a flat plate-like sintered tungsten alloy having a thickness of 0.5 mm similarly to Example 1, except that the thickness of a sintered body obtained in the sintering step was 20 mm, a distortion was introduced into the sintered tungsten alloy by deforming the sintered tungsten alloy in the thickness direction at a deformation rate of 50% in the distortion introducing step, rolling processing was performed until the rolling processing rate in total reached 95% in the hot-rolling step, and the heat treatment temperature was 1600°C in the heat treatment step after the hot-rolling step. However, the flat plate-like sintered tungsten alloy melted. Similarly to Example 1, a cross section of the flat plate-like sintered tungsten alloy after heat treatment after the distortion introducing step was observed by using the optical microscope. As a result of observation, the average grain size of the tungsten crystal grains was approximately 5 ⁇ m.
  • SEM scanning electron microscope
  • first cross section 101 and second cross section 102 a photograph of an arbitrary site (field of view) was taken at a magnification of 1000x, and a photograph of a site (field of view) displaced in this cross section from the arbitrary site along the extending direction of plane 100 was taken. 7 photographs of fields of view obtained by sequential displacement were connected in the extending direction of plane 100 to obtain a photograph of a cross section portion having a thickness T of 70 ⁇ m and a width W of 500 ⁇ m.
  • FIG. 6 shows one example (Example 1) of the scanning electron microscope (SEM) photograph of the cross section portion.
  • Fig. 7 schematically shows the aforementioned cross section portion.
  • measurement was conducted of thicknesses t and lengths s of a plurality of tungsten crystal grains G1 to G4 which intersect with a center line 200 passing through a center of certain width W (500 ⁇ m) and extending in the direction of certain thickness T (70 ⁇ m). Average values of these measurement values were obtained and defined as the average thickness and the average length of the tungsten crystal grains. A ratio of the average length to the average thickness of the tungsten crystal grains was also calculated.
  • Table 1 shows the average thickness and the average length as well as the ratio of the average length to the average thickness of the tungsten crystal grains calculated as described above.
  • a tensile test piece 10 having thickness T was fabricated from the flat plate-like sintered tungsten alloy obtained as a final product in each of Examples 1 to 29 and Comparative Examples 1 to 3, 5, 6, 9, 11 and 12.
  • the gauge length was set at 8 mm with center line 20 centered.
  • Tensile test piece 10 thus fabricated was placed in a tensile test machine of model No. 5867 manufactured by Instron Co., Ltd. and a tensile test was conducted in the ambient atmosphere at a test temperature of 20°C at a tensile speed of 300 mm/min. until rupture occurred. A rate of increase in gauge length of the test piece until rupture occurred was defined as the elongation percentage. As to the flat plate-like sintered tungsten alloy obtained as an intermediate product in Example 1 as well, the elongation percentage was measured similarly to the above.
  • Table 1 shows the measurement result of the elongation percentage obtained as described above.
  • a parenthesized numerical value in "Example 1" in Table 1 represents the elongation percentage of the flat plate-like sintered tungsten alloy obtained as an intermediate product in Example 1.
  • test piece having a thickness of 0.5 mm and having a plane of 8 mmx8 mm was fabricated from the flat plate-like sintered tungsten alloy obtained as a final product in each of Examples 1 to 29 and Comparative Examples 1 to 3, 5, 6, 9, 11 and 12.
  • the plane of 8 mmx8 mm of the fabricated test piece was irradiated with X rays by using an X-ray diffraction device of model No. SmartLab-2D-PILATUS manufactured by Rigaku Corporation, to measure X-ray diffraction intensities of a (111) plane, a (100) plane, a (110) plane, and a (311) plane of a Ni-(Fe, Cu, Co) phase in the flat plate surface.
  • the X-ray diffraction conditions were such that the used X rays were Cu-K ⁇ , excitation conditions were 45 kV and 200 mA, a collimator of ⁇ 0.8mm was used, and a measurement method was a ⁇ -2 ⁇ method.
  • the plane of 8 mmx8 mm serving as the measurement plane was subjected to mechanical polishing and then alkaline electrolytic polishing.
  • an X-ray diffraction intensity ratio of the (111) plane (assuming that the X-ray diffraction intensities of the (111) plane, the (100) plane, the (110) plane, and the (311) plane are I(111), I(100), I(110), and I(311), respectively, the X-ray diffraction intensity ratio of the (111) plane is a value of [I(111)/ ⁇ I(111)+I(100)+I(110)+I(311) ⁇ ]) was calculated.
  • Table 1 shows the measurement result of the X-ray diffraction intensity ratio of the (111) plane of the Ni-(Fe, Cu, Co) phase obtained as described above.
  • Sample No. Tungsten crystal grains (intermediate product) Elongation percentage [%] X-ray diffraction intensity ratio of (111) plane Average thickness [ ⁇ m] Average length [ ⁇ m] Ratio (average length/average thickness)
  • Example 1 5.38 97.42 18.11 27.7(1.0) 0.75
  • Example 3 5.38 97.42 18.11 29.7 0.69
  • Example 4 5.38 97.42 18.11 22.9 0.77
  • Example 5 5.38 97.42 18.11 27.5 0.74
  • Example 6 5.38 97.42 18.11 23.6 0.71
  • Example 7 5.81 108.97 18.76 28.6 0.76
  • Example 8 4.23 94.63 22.37 29.2 0.79
  • Example 9 3.77 85.71 22.73 29.1 0.79
  • Example 10 5.88 54.78 9.32 22.3 0.70
  • a value of the X-ray diffraction intensity ratio of the (111) plane of the Ni-(Fe, Cu, Co) phase is 0.68 or more and 0.9 or less in the sample in each Example of the present invention.
  • the sintered tungsten alloy of the present invention is used as a radiation shield material in radiation medical devices, nuclear reactor-related devices and the like.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)
EP12856450.7A 2011-12-07 2012-11-27 Alliage de tungstène fritté Withdrawn EP2789708A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011267845 2011-12-07
PCT/JP2012/080565 WO2013084749A1 (fr) 2011-12-07 2012-11-27 Alliage de tungstène fritté

Publications (2)

Publication Number Publication Date
EP2789708A1 true EP2789708A1 (fr) 2014-10-15
EP2789708A4 EP2789708A4 (fr) 2015-10-14

Family

ID=48574122

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12856450.7A Withdrawn EP2789708A4 (fr) 2011-12-07 2012-11-27 Alliage de tungstène fritté

Country Status (4)

Country Link
US (1) US20140308536A1 (fr)
EP (1) EP2789708A4 (fr)
JP (2) JP5805213B2 (fr)
WO (2) WO2013084749A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106756379A (zh) * 2017-01-10 2017-05-31 广州市华司特合金制品有限公司 钨合金屏蔽板及设置有钨合金屏蔽板的电子信息卡
RU2623566C1 (ru) * 2016-09-15 2017-06-27 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" (Госкорпорация "Росатом") Способ изготовления спеченных пористых изделий из псевдосплава на основе вольфрама
EP3229268A4 (fr) * 2014-12-05 2018-01-03 Superufo291 Tec Substrat dissipateur de chaleur et procédé pour sa fabrication

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110172598A (zh) * 2018-12-13 2019-08-27 苏州赛特锐精密机械配件有限公司 一种共注射制备双组分钨铜合金的方法
CN111910112B (zh) * 2020-07-01 2022-02-11 昆山家锐电子科技有限公司 一种钨铜合金材料及其制备方法、应用
CN113817944B (zh) * 2021-09-13 2022-10-11 安泰天龙(北京)钨钼科技有限公司 一种高性能钨合金棒材及其制备方法
CN115341125B (zh) * 2022-08-12 2023-06-06 广州市华司特合金制品有限公司 一种钨合金医疗屏蔽板及其制备方法
CN115478236B (zh) * 2022-08-30 2023-02-28 广州市华司特合金制品有限公司 一种高比重钨合金的热处理方法

Family Cites Families (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3254995A (en) * 1962-04-13 1966-06-07 Powder Alloys Corp Heavy metal alloys
US3979234A (en) * 1975-09-18 1976-09-07 The United States Of America As Represented By The United States Energy Research And Development Administration Process for fabricating articles of tungsten-nickel-iron alloy
US4332617A (en) * 1979-09-18 1982-06-01 The United States Of America As Represented By The United States Department Of Energy Method of fabricating thin-walled articles of tungsten-nickel-iron alloy
DE3446334A1 (de) * 1984-12-19 1986-06-19 Philips Patentverwaltung Gmbh, 2000 Hamburg Verfahren zur herstellung von <111>-vorzugsorientiertem wolfram
US4749410A (en) * 1985-07-10 1988-06-07 Gte Products Corporation Elongated tungsten heavy metal aritcle and method for producing same
US4851042A (en) * 1987-05-12 1989-07-25 Rensselaer Polytechnic Institute Hardness and strength of heavy alloys by addition of tantalum
US4801330A (en) * 1987-05-12 1989-01-31 Rensselaer Polytechnic Institute High strength, high hardness tungsten heavy alloys with molybdenum additions and method
US4743512A (en) * 1987-06-30 1988-05-10 Carpenter Technology Corporation Method of manufacturing flat forms from metal powder and product formed therefrom
FR2622209B1 (fr) * 1987-10-23 1990-01-26 Cime Bocuze Alliages lourds de tungstene-nickel-fer a tres hautes caracteristiques mecaniques et procede de fabrication desdits alliages
US4768365A (en) * 1987-11-23 1988-09-06 Gte Products Corporation Process for producing tungsten heavy alloy sheet
JPH02122048A (ja) * 1988-10-31 1990-05-09 Nippon Yakin Kogyo Co Ltd 低温で高延性を有するタングステン焼結合金
JPH0639641B2 (ja) * 1988-10-31 1994-05-25 日本冶金工業株式会社 タングステン焼結合金の製造方法
JPH02259053A (ja) * 1989-03-31 1990-10-19 Mitsubishi Metal Corp 硬質タングステン基焼結合金部材の製造法
JPH0723516B2 (ja) * 1989-11-30 1995-03-15 日本冶金工業株式会社 タングステン焼結合金の製造方法
JPH03173738A (ja) * 1989-11-30 1991-07-29 Nippon Yakin Kogyo Co Ltd 高強度，高靭性タングステン焼結合金
JP2815656B2 (ja) * 1990-01-30 1998-10-27 三菱マテリアル株式会社 パッケージ型半導体装置の高強度放熱性構造部材
JPH042736A (ja) * 1990-04-18 1992-01-07 Japan Steel Works Ltd:The 高靭性Ｗ―Ｎｉ―Ｆｅ焼結合金の製造方法
JP2726140B2 (ja) * 1990-05-31 1998-03-11 日本冶金工業株式会社 高靭性タングステン焼結合金
JPH0436428A (ja) * 1990-05-31 1992-02-06 Nippon Yakin Kogyo Co Ltd 高靭性タングステン焼結合金の製造方法
JPH07116547B2 (ja) * 1990-05-31 1995-12-13 日本冶金工業株式会社 高靭性タングステン焼結合金
JP2819906B2 (ja) * 1991-12-27 1998-11-05 住友金属工業株式会社 室温および高温強度に優れた工具用Ｎｉ基合金
JPH05263163A (ja) * 1992-03-18 1993-10-12 Japan Steel Works Ltd:The Ｗ−Ｎｉ −Ｆｅ 焼結合金の製造方法
KR950005290B1 (ko) * 1992-08-06 1995-05-23 주식회사풍산 충격인성을 갖는 텅스텐 기(基) 합금의 열처리 방법
JPH06316706A (ja) * 1993-04-30 1994-11-15 Japan Steel Works Ltd:The 高強度Ｗ−Ｎｉ−Ｆｅ合金焼結体の製造方法
JP3697559B2 (ja) 1995-08-31 2005-09-21 東邦金属株式会社 放射線遮蔽用タングステン基合金材料
JPH09235641A (ja) 1996-02-28 1997-09-09 Toho Kinzoku Kk タングステン重合金板及びその製法
JP3665169B2 (ja) * 1997-02-03 2005-06-29 株式会社日本製鋼所 高強度高延性タングステン合金の製造方法
DE19824078C2 (de) * 1998-05-29 2001-05-31 Zinser Textilmaschinen Gmbh Verfahren beim Herstellen von verdichtetem Garn und Einrichtung hierfür
US6136105A (en) * 1998-06-12 2000-10-24 Lockheed Martin Corporation Process for imparting high strength, ductility, and toughness to tungsten heavy alloy (WHA) materials
JP2002030372A (ja) * 2000-07-12 2002-01-31 Allied Material Corp 薄物・異形状超重合金板及びその製造方法
JP4259994B2 (ja) * 2003-12-02 2009-04-30 日本ペイント株式会社 重合金シートの製造方法
ES2558877T3 (es) * 2006-06-22 2016-02-09 H.C. Starck Hermsdorf Gmbh Procedimiento para la fabricación de cuerpos moldeados de metal refractario
CN100582267C (zh) * 2008-02-22 2010-01-20 中南大学 一种含稀土的细晶W-Ni-Fe合金的制备方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3229268A4 (fr) * 2014-12-05 2018-01-03 Superufo291 Tec Substrat dissipateur de chaleur et procédé pour sa fabrication
RU2623566C1 (ru) * 2016-09-15 2017-06-27 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" (Госкорпорация "Росатом") Способ изготовления спеченных пористых изделий из псевдосплава на основе вольфрама
CN106756379A (zh) * 2017-01-10 2017-05-31 广州市华司特合金制品有限公司 钨合金屏蔽板及设置有钨合金屏蔽板的电子信息卡
CN106756379B (zh) * 2017-01-10 2019-01-25 广州市华司特合金制品有限公司 钨合金屏蔽板及设置有钨合金屏蔽板的电子信息卡

Also Published As

Publication number Publication date
JP5805213B2 (ja) 2015-11-04
US20140308536A1 (en) 2014-10-16
WO2013084748A1 (fr) 2013-06-13
JPWO2013084749A1 (ja) 2015-04-27
WO2013084749A1 (fr) 2013-06-13
EP2789708A4 (fr) 2015-10-14
JPWO2013084748A1 (ja) 2015-04-27
JP5847196B2 (ja) 2016-01-20

Similar Documents

Publication Publication Date Title
EP2789708A1 (fr) Alliage de tungstène fritté
US10563291B2 (en) Method of forming a sintered nickel-titanium-rare earth (Ni—Ti—Re) alloy
EP3705590B1 (fr) Matériau d&#39;alliage, produit utilisant ledit matériau d&#39;alliage, et machine hydraulique ayant ledit produit
JP6677875B2 (ja) 多結晶タングステン及びタングステン合金焼結体並びにその製造方法
EP2804711B1 (fr) Melange de poudre sur préparation d&#39;un alliage de nickel-titane-metaux de terres rares
KR101693814B1 (ko) 티타늄이 포함된 산화물 분산 강화 분산동 합금 및 그의 제조방법
JP2016512287A (ja) ニッケル−チタン合金の熱機械処理
CN105063394B (zh) 一种钛或钛合金材料的制备方法
JP5855435B2 (ja) α＋β型またはβ型チタン合金およびその製造方法
KR102373916B1 (ko) 다결정 텅스텐 소결체 및 다결정 텅스텐 합금 소결체 그리고 그것들의 제조 방법
EP3369833B1 (fr) Acier inoxydable austénitique à durcissement par phase dispersée, procédé pour la fabrication de l&#39;acier inoxydable et produit fabriqué à partir de l&#39;acier inoxydable
EP2189548B1 (fr) Matériau amortissant les contraintes
CN113165077A (zh) 由层叠成型体构成的Ni基合金构件、Ni基合金构件的制造方法以及使用Ni基合金构件的产品
Gülsoy et al. Injection molding of mechanical alloyed Ti–Fe–Zr powder
KR102198726B1 (ko) 스퍼터링 타깃용 재료
KR102314078B1 (ko) 산화물분산강화 합금 제조방법
CN114629267A (zh) 非磁性构件及其制造方法
Rajath Hegde et al. Synthesis, characterization and annealing of mechanically alloyed nanostructured FeAl powder
CN118284711A (zh) 钛材料
Guo Fabrication, microstructure and properties of a multifunctional titanium alloy

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20140627

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAX Request for extension of the european patent (deleted)
RA4 Supplementary search report drawn up and despatched (corrected)

Effective date: 20150910

RIC1 Information provided on ipc code assigned before grant

Ipc: C22C 27/04 20060101AFI20150904BHEP

Ipc: C22F 1/18 20060101ALI20150904BHEP

Ipc: B22F 3/24 20060101ALI20150904BHEP

Ipc: C22C 1/04 20060101ALI20150904BHEP

Ipc: C22F 1/00 20060101ALI20150904BHEP

17Q First examination report despatched

Effective date: 20160408

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20160819