MOLYBDENUM MATERIAL AND METHOD FOR MANUFACTURING THE SAME
A molybdenum material having a diameter of 75 mm or more and a length of 250 mm or more, and having a relative density of 99.5% or more.
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The present invention relates to a molybdenum material. The present application claims priority based on Japanese Patent Application No. 2018-063888 filed on Mar. 29, 2018. The entire contents described in the Japanese patent application are incorporated herein by reference.
BACKGROUND ARTConventional molybdenum materials are disclosed, for example, in Japanese Patent Laying-Open Nos. 2007-169789 and 2007-113033.
CITATION LIST Patent Literature
- [PTL 1] Japanese Patent Laying-Open No. 2007-169789
- [PTL 2] Japanese Patent Laying-Open No. 2007-113033
A molybdenum material according to one aspect of the present invention is a molybdenum material having a diameter of 75 mm or more and a length of 250 mm or more, and having a relative density of 99.5% or more.
Conventional molybdenum materials have not been able to obtain large volumes. The present invention has been made to solve the above problem.
Description of Embodiments of the Present Invention (1) Summary of EmbodimentsA molybdenum material according to one embodiment of the present invention is a molybdenum material having a diameter of 75 mm or more and a length of 250 mm or more, and having a relative density of 99.5% or more.
Preferably, the molybdenum material has a relative density of 99.9% or more.
In one embodiment of the present invention, the molybdenum material contains 99.9% by mass or more of molybdenum.
In one embodiment of the present invention, the molybdenum material contains 0.3% by mass or more and 1.5% by mass or less of titanium, 0.03% by mass or more and 0.1% by mass or less of zirconium, and 0.01% by mass or more and 0.3% by mass or less of carbon, with a balance composed of molybdenum and unavoidable impurity.
A method for manufacturing a molybdenum material preferably comprises: (1) preparing a first core alloy having an outer diameter of 40 mm or less by hot isostatic pressing; (2) disposing the first core alloy in a tube having a diameter larger than that of the first core alloy; (3) disposing molybdenum powder in the tube around the first core alloy and subsequently compressing the tube by hot isostatic pressing; (4) removing the compressed tube to form a second core alloy having a diameter larger than that of the first core alloy; and repeating the steps (2) to (4).
(2) Comparison with Prior ArtAccording to PTL 1, in an example, W powder having a particle size of 4.1 μm was pressed with a pressure of 200 MPa by CIP (Cold Isostatic Pressing) and sintered in a hydrogen atmosphere having a temperature of 2250° C. to obtain a sintered rod having a relative density of 92%. In a subsequent step, the sintered rod was pressed by HIP (Hot Isostatic Pressing) at a temperature of 1750° C. and a pressure of 195 MPa for 3 hours to obtain a sintered rod having a relative density of 97.9%. A radial forging machine is used to form the rod with a forming degree of 67% to obtain a tungsten rod having an overall average relative density of 99.66% and having a relative core density of 99.63%. After the rod is annealed at a temperature of 1800° C. for 4 hours, it provides a crystal grain size, that is, about 800 crystal grains on average per square millimeter at a center portion of the rod and about 850 crystal grains on average per square millimeter at peripheral portion of the rod.
According to PTL 2, in an example, Mo powder having an average particle size of 45 μm or less is introduced into a soft steel can, and subsequently, the soft steel can is heated at 400° C. and vacuum-degassed, and thus sealed. The soft steel can was pressed by HIP at a temperature of 1250° C. and a pressure of 148 MPa for 5 hours to provide a Mo sintered body having a relative density of 99.8%. The Mo sintered body is cut to provide a plate having a length of 380 mm, a width of 110 mm, and a thickness of 8.1 mm, and the plate is heated to 700° C. and subsequently subjected to plastic working by rolling in a temperature range of 200° C. or higher to obtain a thickness of 4.6 mm.
The methods described in PTLs 1 and 2 do not meet customers' demand for efficient production of Mo material. In addition, the methods cannot produce a large-volume Mo material with little unevenness in density, that is required to meet demands for components such as furnace materials to have large size and high strength.
When a Mo material is manufactured through powder metallurgy, e.g., by pressing followed by sintering, or pressing by HIP, or the like, the resulting, sintered alloy tends to have an inner portion having a lower density and a peripheral portion having a higher density. This unevenness in density between the inner portion and the peripheral portion increases as the product's size increases. When the unevenness in density is corrected by plastic working involving a large amount of deformation, a large stress must be applied to the Mo material by hot working.
For the above reasons, increasing the diameter of a Mo material requires employing a large-sized preheating furnace and a large-sized hot plastic working apparatus. In addition, if the Mo material is not quickly transported from the non-oxidizing atmosphere in the preheating furnace to the air atmosphere in which the plastic working apparatus is disposed, the Mo material's temperature is reduced, and the Mo material cracks during plastic working. However, as the facilities are increased in size, and the Mo material is also increased in size and hence weight, it is difficult to quickly transport the Mo material.
In the present disclosure, as indicated in an embodiment by way of example, a Mo sintered body can be produced in a stepwise manner from a center side toward a peripheral side to have an overall high density to obtain a rod-shaped Mo material having a diameter of 75 mm or more which has not conventionally been achieved. By using the Mo material, a large number of components having uniform density can be obtained. When the Mo material is used for a target, the Mo material, having a uniform density, allows a large number of wafers which are uniformly consumed and thus have good consumability to be obtained. When the Mo material is used for a heater, the Mo material allows a large number of heating elements with small variation in electrical resistance and less likely to break to be obtained. When the Mo material is used for a furnace material, the Mo material allows a large number of members having uniform material strength to be obtained. When the Mo material is used for an electrode for resistance welding, the Mo material, having a uniform density, allows a large number of electrodes with small variation in bonding conditions to be obtained.
(3) Dimension of Mo MaterialThe Mo material has a diameter of 75 mm or more. The Mo material preferably has a diameter of 300 mm or less. When the Mo material has a diameter of 75 mm or more, the Mo material can be used for a large-volume component, for example, the aforementioned target, heater, furnace material, or electrode for resistance welding. Preferably, the Mo material has a diameter of 140 mm or more. More preferably, the Mo material has a diameter of 200 mm or more.
While the Mo material may have any diameter equal to or larger than 75 mm, it is preferably 300 mm or less from the viewpoint of actual use. The diameter of the Mo material is measured in a method as follows: the Mo material have a plurality of any portions thereof measured in diameter with a caliper, and an average value of maximum and minimum diameters measured is defined as the diameter of the Mo material.
Variation in diameter of the Mo material is preferably 20% or less. When the Mo material has a variation in diameter exceeding 20%, and a black skin formed on a periphery of the Mo material is removed by machining, it could be difficult to remove the black skin. It should be noted that the word “could” is intended to mean that there is a slight possibility that something will happen, and is not intended to mean that there is a high probability that it will happen.
The Mo material is not limited in shape to a cylindrical shape, and may have a polygonal shape. When the Mo material has a polygonal shape, the diameter of an imaginary circle having a maximum area inside the polygonal shape is defined as the diameter of the Mo material.
Further, the Mo material is measured in density at a portion inside the imaginary circle having the maximum area. The Mo material has a length of 250 mm or more. The Mo material preferably has a length of 1500 mm or less. When the Mo material has a length of 250 mm or more, and, for example, the aforementioned components are formed of the Mo material, a large number of such components can be obtained from the Mo material at a time. When the Mo material has a length of less than 250 mm, it could provide a small yield of such components and hence poor production efficiency. Further, without using a process in the present embodiment, a conventional process can also enhance the density of a center portion of the Mo material. While the Mo material may have any length equal to or larger than 250 mm, it is preferably 1500 mm or less from the viewpoint of actual use.
The Mo material internally has a relative density of 99.5% or more. When the Mo material internally has a relative density of 99.5% or more, and a large number of the aforementioned components are obtained from each portion of the Mo material, the components can have a small difference in density. Preferably, Mo material internally has a relative density of 99.9% or more. More preferably, the Mo material internally has a relative density of 100%.
When the Mo material internally has a relative density of less than 99.5%, it could provide components with a large unevenness in density therebetween, and hence variation in characteristics as components.
The Mo material's internal relative density is measured in the following method. Note that in the following description, the Mo material's relative density may simply be referred to as relative density. A disc having a thickness of 30 mm is cut out of the obtained rod-shaped Mo material at its opposite ends and center portion in its longitudinal direction for a total of three locations. As locations for evaluation, a total of three portions of each disc cut out, i.e., a portion in a vicinity of a surface, a center, and an intermediate portion between the vicinity of the surface and the center in the radial direction of the disc, are selected, and a test piece of 10×10×10 mm is cut out therefrom and subjected to measurement in relative density of the Mo material in Archimedes' method. Specifically, the Mo material's relative density is calculated from the composition of the Mo material, a theoretical density calculated from the composition of the Mo material, the volume of the test piece, and the mass of the test piece. The volume of the test piece is a volume corresponding to an increase of water in level in a beaker when the test piece is put in the beaker for the sake of illustration. The mass of the test piece is measured with an electronic balance.
The Mo material's relative density is determined by the following equation:
Mo material's relative density=(mass of test piece/volume of test piece)/theoretical density
The theoretical density is determined by the composition of the Mo material.
The Mo material may contain 99.9% by mass or more of Mo. When this Mo material is compared with a Mo material having a Mo content of less than 99.9% by mass, the former has better machinability and plastic workability than the latter.
The Mo material may contain 0.3% by mass or more and 1.5% by mass or less of Ti, 0.03% by mass or more and 0.1% by mass or less of Zr, and 0.01% by mass or more and 0.3% by mass or less of C, with a balance composed of Mo, unavoidable impurity and unavoidable gaseous impurity. When this Mo material is compared with the Mo material having a Mo content of 99.9% by mass or more, the former can have higher mechanical strength than the latter.
The unavoidable impurity for example includes at least one of Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, Si, Na, K and W. The unavoidable gaseous impurity for example includes at least one of N and O. The Mo material preferably contains 0.1% by mass or less of unavoidable impurity in a total amount. The Mo material preferably contains 0.01% by mass or less of unavoidable gaseous impurity in a total amount.
When the Mo material has a Ti content in mass exceeding 1.5% by mass, the Mo material could fail to have a sufficient density. When the Mo material has a Ti content in mass of less than 0.3% by mass, the Mo material could fail to have a strength exceeding that of pure Mo. Note that pure Mo is a material of molybdenum having a Mo content in mass of 99.9% by mass or more.
When the Mo material has a Zr content in mass exceeding 0.1% by mass, the Mo material could fail to have a sufficient density. When the Mo material has a Zr content in mass of less than 0.03% by mass, the Mo material could fail to have a strength exceeding that of pure Mo.
When the Mo material has a C content in mass exceeding 0.3% by mass, the Mo material could fail to have a sufficient density. When the Mo material has a C content in mass of less than 0.01% by mass, the Mo material could fail to have a strength exceeding that of pure Mo.
When the Mo material contains unavoidable impurity in a total amount exceeding 0.1% by mass, the Mo material could fail to have a sufficient density and stable characteristics. When the Mo material contains unavoidable gaseous impurity exceeding 0.01% by mass in a total amount, the Mo material could fail to have a sufficient density and stable characteristics.
The composition of metal elements is measured through ICP (Inductively Coupled Plasma Emission Spectroscopy) according to JIS H1404 (2001). ICPS-8100 manufactured by Shimadzu Corporation is used to measure metal elements through ICP. C is measured with EMIA-920-V2 manufactured by HORIBA, Ltd. O and N are measured with ON-836 manufactured by LECO JAPAN CORPORATION.
The Mo material preferably has a tensile strength of 400 MPa or more at room temperature and a tensile strength of 50 MPa or more at 1000° C. When the Mo material does not satisfy these tensile strengths, and for example it is used for a furnace material, the Mo material could be deformed in use.
The Mo material preferably includes, per square centimeter, no pore having a diameter of 30 μm or more and 200 or less pores having a diameter of less than 30 μm.
The number of pores included in the Mo material is counted in the following method. A disc-shaped sample having a thickness of 15 mm and a diameter of 10 mm is cut out of the obtained rod-shaped Mo material at the center and in a vicinity of a surface in the radial direction. Each sample has a cut surface polished to have a polished surface with a surface roughness (Rz) of 0.2 μm or less. The sample is polished for example as follows: the cut surface is polished with a waterproof paper of #180 to 2000 and subsequently buff-polished using a suspension of diamond having a particle size of 1 to 3 μm.
The sample's polished surface is observed with a stereomicroscope SZ40 manufactured by Olympus Corporation, and where a pore having a maximum diameter is located is confirmed. A range extracted from the polished surface of the sample including the location of the pore having the maximum diameter is observed at a magnification of 1000 times with a microscope VHX-6000 manufactured by Keyence Corporation to measure the maximum diameter of the pore. The maximum diameter of the pore is defined as the diameter of the inscribed circle of the observed pore. For the sake of illustration, the extracted range is within a circle having a radius of 4 mm from the center of the polished surface of the sample having a diameter of 10 mm. Further, the extracted range is enlarged by 100 times, and what has a different matrix and a different contrast is all determined as void and extracted, and subjected to contamination analysis to count the number of pores. In doing so, the number of pores is counted with an extraction parameter adjusted so that the pore's maximum diameter matches a measured value thereof as observed at the magnification of 1000 times.
When the Mo material includes, per square centimeter, pores having a diameter of 30 μm or more and more than 200 pores having a diameter of less than 30 μm, and the Mo material is used for example for a target, a film formed by sputtering could have large variation in thickness.
Detailed Description of Embodiments of the Present InventionHereinafter, the present invention will be described based on examples.
Example 1(1) Process for Manufacturing Mo Sintered Body which is Mo Material
(1-1) Raw Material
As a raw material, Mo powder having an Fsss value of 4.0 μm as measured in the Fisher method was used. The Fsss value is preferably 3 μm or more and 10 μm or less. An Fsss value exceeding 10 μm could result in a Mo sintered body failing to have an overall increased density. An Fsss value of less than 3 μm could result in a Mo sintered body failing to have a center portion with an increased density. Pure Mo powder was used as raw material powder.
(1-2) Core Alloy
In Example 1, Mo materials of Sample Nos. 1 to 3 and 101 shown in Table 1 were produced.
In order to obtain the sintered core bodies of Sample Nos. 1 to 3 and 101 shown in Table 1, four capsules 21 each being a tube shown in
After raw material powder of Mo 10 is introduced into capsule 21 to have a bulk density of 4.2 g/cm3, a lid 22 having a hot-degassing pipe 23 welded thereto was welded to capsule 21 using TIG (Tungsten Inert Gas). A hose connected to an oil rotary pump and an oil diffusion pump was attached to a tip 25 of pipe 23.
A container with capsule 21 having lid 22 welded thereto was placed in an atmospheric furnace held at a temperature of 500° C. and vacuumed using the oil rotary pump and the oil diffusion pump so that the container had an internal pressure reduced from normal atmospheric pressure to 1×10−3 Pa. The container thus hot-degassed was extracted and had pipe 23 collapsed at a position to be provided with a seal portion 24, and cut off at the collapsed portion, and the cut pipe had an end TIG-welded and thus sealed to have seal portion 24.
The soft steel can preferably has a thickness of 3 mm or more and 20 mm or less. When the soft steel can has a thickness exceeding 20 mm, and pressure-sintered, the resulting Mo alloy could fail to have an increased density. When the soft steel can has a thickness of less than 3 mm, and pressure-sintered, capsule 21 could be broken. Capsule 21 may have a circumference and a bottom formed integrally, and when capsule 21 has a large size, the capsule may have a circumference and a bottom that are separate members TIG-welded and thus bonded together. Lid 22 can for example be a plate material having the same thickness as capsule 21.
In hot-degassing the container, the furnace preferably has an internal temperature of 400° C. or higher and 500° C. or lower. When the furnace's temperature exceeds 500° C., and the container internally has a low degree of vacuum, the Mo powder could be oxidized. When the furnace's temperature is lower than 400° C., a gas component or the like adsorbed on the Mo powder could be insufficiently degassed, and the Mo alloy may have pores therein.
The container is hot-degassed preferably for 1 hour or more and 5 hours or less after capsule 21 attains the same temperature as that of the interior of the furnace. Once a period of time for which the container is hot-degassed exceeds 5 hours, the Mo alloy no longer has its characteristics improved, and hot-degassing the container for a period of time exceeding 5 hours thus results in impaired economy. When the container is hot-degassed for less than 1 hour, a gas component or the like adsorbed on the Mo powder could be insufficiently degassed, and the Mo alloy may have pores therein.
When the container is hot-degassed, its internal ultimate pressure is preferably less than 1×10−2 Pa. When the container's internal ultimate pressure is 1×10−2 Pa or more, the container could be insufficiently degassed, and when it is HIPed, the Mo alloy's density could be less likely to increase.
The Mo powder in the container preferably has a bulk density of 2.5 g/cm3 or more and 5.0 g/cm3 or less. When the Mo powder has a bulk density exceeding 5.0 g/cm3, a gas component or the like adsorbed on the Mo powder could be insufficiently degassed, and the Mo alloy's density could be less likely to increase. When the Mo powder has a bulk density of less than 2.5 g/cm3, and is HIPed, the Mo alloy's shrinkability is excessively large, and a resulting Mo sintered body could fail to have a targeted shape. More preferably, the Mo powder in the container has a bulk density of 3.5 g/cm3 or more and 4.5 g/cm3 or less.
(1-3) Sintering
The sealed container was placed in a furnace of a hot isostatic pressing apparatus and subjected to pressure-sintering by HIP at a temperature of 1280° C. and a pressure of 147 MPa for 5 hours. Hereinafter, pressure-sintering by HIP may simply be referred to as HIP. As shown in
After the container was pressure-sintered, the container was removed by machining to obtain a sintered core body 11, as shown in
Sintered core body 11 had its relative density measured in Archimedes' method, and it had a relative density of 99.5% or more and 99.9% or less at a center portion in the radial direction and a relative density of 100% at a portion other than the center portion. The HIP is performed with a heating temperature preferably of 1000° C. or higher and 1350° C. or lower. When the heating temperature exceeds 1350° C., it is a temperature close to the melting point of the soft steel constituting capsule 21, and capsule 21 could be broken during the HIP. When the heating temperature is lower than 1000° C., the Mo alloy's density could fail to increase during the HIP.
In the HIP, the container's internal ultimate pressure is preferably 98 MPa or more and 250 MPa or less. Once the container's internal ultimate pressure exceeds 250 MPa, the Mo alloy's density no longer increases, and HIPing the container beyond 250 MPa results in impaired economy. When the container's internal ultimate pressure is less than 98 MPa, the Mo alloy's density could fail to increase. The HIP is applied preferably for 1 hour or more and 10 hours or less. Applying the HIP beyond 10 hours does not further increase the Mo alloy's density, and HIPing the container beyond 10 hours results in impaired economy. When the HIP is applied for less than 1 hour, the Mo alloy's density could fail to increase.
When removing the soft steel can of the container, the Mo alloy's machining margin is preferably 3 mm or more and 10 mm or less. When the Mo alloy's machining margin exceeds 10 mm it results in an increased processing time and a reduced yield of material, and hence impaired economy. When the Mo alloy's machining margin is less than 3 mm, the soft steel can could be incompletely removed from the Mo alloy.
(1-4) Increasing Diameter
In order to increase the diameters of sintered core bodies 11 of Sample Nos. 1 to 3 in Table 1, capsules 21 of three soft steel cans each shown in
Subsequently, pressure-sintering by HIP was performed as described in the “(1-3) Sintering” section, and thereafter the container was removed by machining. Thus, Mo sintered bodies as second core alloys of Sample Nos. 1 to 3 having diameters and lengths as indicated in Table 1 at the “1st time” column were obtained.
In order to further increase the diameters of the obtained Mo sintered bodies, capsules 21 of three soft steel cans each shown in
Subsequently, pressure-sintering by HIP was performed as described in the “(1-3) Sintering” section, and thereafter the container was removed by machining. Thus, Mo sintered bodies as Mo materials of Sample Nos. 1 to 3 having diameters and lengths as indicated in Table 1 at the “2nd time” column were obtained.
(2) Evaluation of Mo Material
The rod-shaped Mo materials of Sample Nos. 1 to 3 and 101 having a diameter of 75 mm and a length of 1500 mm, as obtained through the above process, were each cut at a front end 1, a center 2 at a rear end 3, as shown in
As shown in Table 1, it has been confirmed that the Mo materials of Sample Nos. 1 to 3 of Example 1 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 1 and 2 of Example 1 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 101 as a Comparative Example had a relative density including a portion less than 99.5%.
Example 2In Example 2, sintered core body 11 was produced in the same manner as in Example 1 except that the length was 1000 mm, and sintered core body 11 was additionally HIPed twice to have an increased diameter to thus produce Mo materials for Sample Nos. 4 to 6. For a comparative example, a Mo material for Sample No. 102 was produced in the same manner as Sample No. 101 except that the length was 1000 mm. In the same manner as in Example 1, test pieces were cutout and subjected to measurement of relative density. A result thereof is shown in Table 2.
As shown in Table 2, it has been confirmed that the Mo materials of Sample Nos. 4 to 6 of Example 2 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 4 and 5 of Example 2 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 102 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 3In Example 3, sintered core body 11 was produced in the same manner as in Example 1 except that the length was 500 mm, and sintered core body 11 was additionally HIPed twice to have an increased diameter to thus produce Mo materials for Sample Nos. 7 to 9. For a comparative example, a Mo material for Sample No. 103 was produced in the same manner as Sample No. 101 except that the length was 500 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 3.
As shown in Table 3, it has been confirmed that the Mo materials of Sample Nos. 7 to 9 of Example 3 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 7 and 8 of Example 3 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 103 as the Comparative Example had a relative density including a portion less than 99.5%. [0069] (Example 4) In Example 4, sintered core body 11 was produced in the same manner as in Example 1 except that the length was 250 mm, and sintered core body 11 was additionally HIPed twice to have an increased diameter to thus produce Mo materials for Sample Nos. 10 to 12. For a comparative example, a Mo material for Sample No. 104 was produced in the same manner as Sample No. 101 except that the length was 250 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 4.
As shown in Table 4, it has been confirmed that the Mo materials of Sample Nos. 10 to 12 of Example 4 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 10 and 11 of Example 4 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 104 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 5In Example 5, in order to obtain sintered core bodies 11 for Sample Nos. 13 to 15, capsules 21 of three soft steel cans each shown in
As shown in Table 5, it has been confirmed that the Mo materials of Sample Nos. 13 to 15 of Example 5 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 13 and 14 of Example 5 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 105 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 6In Example 6, sintered core body 11 was produced in the same manner as in Example 5 except that the length was 1000 mm, and sintered core body 11 was additionally HIPed twice or three times to have an increased diameter to thus produce Mo materials for Sample Nos. 16 to 18. For a comparative example, a Mo material for Sample No. 106 was produced in the same manner as Sample No. 105 except that the length was 1000 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 6.
As shown in Table 6, it has been confirmed that the Mo materials of Sample Nos. 16 to 18 of Example 6 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 16 and 17 of Example 6 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 106 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 7In Example 7, sintered core body 11 was produced in the same manner as in Example 5 except that the length was 500 mm, and sintered core body 11 was additionally HIPed twice or three times to have an increased diameter to thus produce Mo materials for Sample Nos. 19 to 21. For a comparative example, a Mo material for Sample No. 107 was produced in the same manner as Sample No. 105 except that the length was 500 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 7.
As shown in Table 7, it has been confirmed that the Mo materials of Sample Nos. 19 to 21 of Example 7 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 19 and 20 of Example 7 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 107 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 8In Example 8, sintered core body 11 was produced in the same manner as in Example 5 except that the length was 250 mm, and sintered core body 11 was additionally HIPed twice or three times to have an increased diameter to thus produce Mo materials for Sample Nos. 22 to 24. For a comparative example, a Mo material for Sample No. 108 was produced in the same manner as Sample No. 105 except that the length was 250 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 8.
As shown in Table 8, it has been confirmed that the Mo materials of Sample Nos. 22 to 24 of Example 8 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 22 and 23 of Example 8 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 108 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 9In Example 9, in order to obtain sintered core bodies 11 for Sample Nos. 25 to 27, capsules 21 of three soft steel cans each shown in
As shown in Table 10, it has been confirmed that the Mo materials of Sample Nos. 25 to 27 of Example 9 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 25 and 26 of Example 9 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 109 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 10In Example 10, sintered core body 11 was produced in the same manner as in Example 9 except that the length was 1000 mm, and sintered core body 11 was additionally HIPed four or five times to have an increased diameter to thus produce Mo materials for Sample Nos. 28 to 30. For a comparative example, a Mo material for Sample No. 110 was produced in the same manner as Sample No. 109 except that the length was 1000 mm. In the same manner as in Example 1, test pieces were cutout and subjected to measurement of relative density. A result thereof is shown in Tables 11 and 12.
As shown in Table 12, it has been confirmed that the Mo materials of Sample Nos. 28 to 30 of Example 10 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 28 and 29 of Example 10 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 110 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 11In Example 11, sintered core body 11 was produced in the same manner as in Example 9 except that the length was 500 mm, and sintered core body 11 was additionally HIPed four or five times to have an increased diameter to thus produce Mo materials for Sample Nos. 31 to 33. For a comparative example, a Mo material for Sample No. 111 was produced in the same manner as Sample No. 109 except that the length was 500 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 13 and 14.
As shown in Table 14, it has been confirmed that the Mo materials of Sample Nos. 31 to 33 of Example 11 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 31 and 32 of Example 11 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 111 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 12In Example 12, sintered core body 11 was produced in the same manner as in Example 9 except that the length was 250 mm, and sintered core body 11 and additionally HIPed four or five times to have an increased diameter to thus produce Mo materials for Sample Nos. 34 to 36. For a comparative example, a Mo material for Sample No. 112 was produced in the same manner as Sample No. 109 except that the length was 250 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 15 and 16.
As shown in Table 16, it has been confirmed that the Mo materials of Sample Nos. 34 to 36 of Example 12 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 34 and 35 of Example 12 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 112 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 13In Example 13, in order to obtain sintered core bodies 11 for Sample Nos. 37 to 39, capsules 21 of three soft steel cans each shown in
As shown in Table 18, it has been confirmed that the Mo materials of Sample Nos. 37 to 39 of Example 13 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 37 and 38 of Example 13 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 113 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 14In Example 14, sintered core body 11 was produced in the same manner as in Example 13 except that the length was 1000 mm, and sintered core body 11 was additionally HIPed six or seven times to have an increased diameter to thus produce Mo materials for Sample Nos. 40 to 42. For a comparative example, a Mo material for Sample No. 110 was produced in the same manner as Sample No. 113 except that the length was 1000 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 19 and 20.
As shown in Table 20, it has been confirmed that the Mo materials of Sample Nos. 40 to 42 of Example 14 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 40 and 41 of Example 14 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 114 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 15In Example 15, sintered core body 11 was produced in the same manner as in Example 13 except that the length was 500 mm, and sintered core body 11 was additionally HIPed six or seven times to have an increased diameter to thus produce Mo materials for Sample Nos. 43 to 45. For a comparative example, a Mo material for Sample No. 115 was produced in the same manner as Sample No. 113 except that the length was 500 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 21 and 22.
As shown in Table 22, it has been confirmed that the Mo materials of Sample Nos. 43 to 45 of Example 15 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 43 and 44 of Example 15 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 115 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 16In Example 16, sintered core body 11 was produced in the same manner as in Example 13 except that the length was 250 mm, and sintered core body 11 was additionally HIPed six or seven times to have an increased diameter to thus produce Mo materials for Sample Nos. 46 to 48. For a comparative example, a Mo material for Sample No. 116 was produced in the same manner as Sample No. 113 except that the length was 250 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 23 and 24.
As shown in Table 24, it has been confirmed that the Mo materials of Sample Nos. 46 to 48 of Example 16 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 47 and 48 of Example 16 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 116 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 17In Example 17, in order to obtain sintered core bodies 11 for Sample Nos. 49 to 51, capsules 21 of three soft steel cans each shown in
As shown in Table 26, it has been confirmed that the Mo materials of Sample Nos. 49 to 51 of Example 17 had a relative density of 99.6% or more. It has been confirmed that the Mo materials of Sample Nos. 49 and 50 of Example 17 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 117 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 18In Example 18, sintered core body 11 was produced in the same manner as in Example 17 except that the length was 1000 mm, and sintered core body 11 was additionally HIPed nine or ten times to have an increased diameter to thus produce Mo materials for Sample Nos. 52 to 54. For a comparative example, a Mo material for Sample No. 118 was produced in the same manner as Sample No. 117 except that the length was 1000 mm. In the same manner as in Example 1, test pieces were cutout and subjected to measurement of relative density. A result thereof is shown in Tables 27 and 28.
As shown in Table 27, it has been confirmed that the Mo materials of Sample Nos. 52 to 54 of Example 18 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 52 and 53 of Example 18 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 118 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 19In Example 19, sintered core body 11 was produced in the same manner as in Example 17 except that the length was 500 mm, and sintered core body 11 was additionally HIPed nine or ten times to have an increased diameter to thus produce Mo materials for Sample Nos. 55 to 57. For a comparative example, a Mo material for Sample No. 119 was produced in the same manner as Sample No. 117 except that the length was 500 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 29 and 30.
As shown in Table 30, it has been confirmed that the Mo materials of Sample Nos. 55 to 57 of Example 19 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 55 and 56 of Example 19 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 119 as the Comparative Example had a relative density including a portion less than 99.5%.
Example 20In Example 20, sintered core body 11 was produced in the same manner as in Example 17 except that the length was 250 mm, and sintered core body 11 was additionally HIPed nine or ten times to have an increased diameter to thus produce Mo materials for Sample Nos. 58 to 60. For a comparative example, a Mo material for Sample No. 120 was produced in the same manner as Sample No. 117 except that the length was 250 mm. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 31 and 32.
As shown in Table 32, it has been confirmed that the Mo materials of Sample Nos. 58 to 60 of Example 20 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 58 and 59 of Example 20 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 120 as the Comparative Example had a relative density including a portion less than 99.5%.
From the results of Examples 1 to 20, it has been confirmed that, even when the Mo material contains 99.9% by mass or more of Mo, the Mo material can have a relative density of 99.5% or more, and furthermore, the Mo material can also have a relative density of 99.9% or more.
Example 21In Example 21, Mo materials for Sample Nos. 301 to 303 and 601 were produced in the same manner as in Example 17 except that the Mo materials had a composition changed by adding a Ti component, a Zr component and a C component to a Mo component of a raw material. Specifically, Mo powder, TiC powder, and ZrC powder were mixed together to prepare raw material powder. The Mo powder had an Fsss value of 4.0 μm. The TiC powder had an Fsss value of 2.0 μm. The ZrC powder had an Fsss value of 3.0 μm.
The Mo powder preferably has an Fsss value of 3 μm or more and 10 μm or less. When the Mo powder has an Fsss value exceeding 10 μm, it could result in a Mo sintered body failing to have an overall increased density. When the Mo powder has an Fsss value of less than 3 μm, it could result in a Mo sintered body failing to have a center portion with an increased density. The TiC powder preferably has an Fsss value of 1 μm or more and 20 μm or less. When the TiC powder has an Fsss value exceeding 20 μm, it could result in a Mo sintered body failing to have an overall increased density. When the TiC powder has an Fsss value of less than 1 μm, it could result in a Mo sintered body failing to have a center portion with an increased density. The ZrC powder preferably has an Fsss value of 1 μm or more and 20 μm or less. When the ZrC powder has an Fsss value exceeding 20 μm, it could result in a Mo sintered body failing to have an overall increased density. When the ZrC powder has an Fsss value of less than 1 μm, it could result in a Mo sintered body failing to have a center portion with an increased density.
Instead of TiC powder, pure Ti powder or TiH powder may be mixed. Instead of ZrC powder, pure Zr powder or ZrH powder may be mixed. In these cases, C powder is mixed with raw material powder. C powder may also be mixed with raw material powder when TiC powder and ZrC powder are used. The C powder preferably has an Fsss value of 0.1 μm or more and 10 μm or less. When the C powder has an Fsss value exceeding 10 μm, it could result in a Mo sintered body failing to have an overall increased density. When the C powder has an Fsss value of less than 0.1 μm, it could result in a Mo sintered body failing to have a center portion with an increased density. Note that pure Ti is a titanium material having a Ti content in mass of 99.9% by mass or more. Note that pure Zr is a zirconium material having a Zr content in mass of 99.9% by mass or more.
Table 33 shows a content in mass of each component according to a weighed value of raw material powder and a content in mass of each component according to a measured value of a composition of each Mo material in Example 21. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 34 and 35.
As shown in Table 35, it has been confirmed that the Mo materials of Sample Nos. 301 to 303 of Example 21 had a relative density of 99.6% or more. It has been confirmed that the Mo materials of Sample Nos. 301 and 302 of Example 21 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 601 as a Comparative Example had a relative density including a portion less than 99.5%.
Example 22In Example 22, Mo materials for Sample Nos. 401 to 403 and 602 were produced in the same manner as in Example 21 except for the compositions of the Mo materials. Table 36 shows a content in mass of each component according to a weighed value of raw material powder and a content in mass of each component according to a measured value of a composition of each Mo material in Example 22. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 37 and 38.
As shown in Table 38, it has been confirmed that the Mo materials of Sample Nos. 401 to 403 of Example 22 had a relative density of 99.6% or more. It has been confirmed that the Mo materials of Sample Nos. 401 and 402 of Example 22 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 602 as a Comparative Example had a relative density including a portion less than 99.5%.
Example 23In Example 23, Mo materials for Sample Nos. 501 to 503 and 603 were produced in the same manner as in Example 21 except for the compositions of the Mo materials. Table 39 shows a content in mass of each component according to a weighed value of raw material powder and a content in mass of each component according to a measured value of a composition of each Mo material in Example 23. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Tables 40 and 41.
As shown in Table 41, it has been confirmed that the Mo materials of Sample Nos. 501 to 503 of Example 23 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 501 and 502 of Example 23 had a relative density of 99.9% or more. It has been confirmed that the Mo material of Sample No. 603 as a Comparative Example had a relative density including a portion less than 99.5%.
From the results of Examples 21 to 23, it has been confirmed that a Mo material that contains 0.3% by mass or more and 1.5% by mass or less of titanium, 0.03% by mass or more and 0.1% by mass or less of zirconium, and 0.01% by mass or more and 0.3% by mass or less of carbon, with a balance composed of molybdenum and unavoidable impurity, can also have a relative density of 99.5% or more, and furthermore, can also have a relative density of 99.9% or more.
Example 24In Example 24, Mo materials for Sample Nos. 701 to 705 and 601 were produced in the same manner as in Example 21 except that HIP was not additionally performed. Table 42 shows a content in mass of each component according to a weighed value of raw material powder and a content in mass of each component according to a measured value of a composition of each Mo material in Example 24. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 43.
As shown in Table 43, it has been confirmed that the Mo materials of Sample Nos. 701 to 703 of Example 24 had a relative density of 99.6% or more. It has been confirmed that the Mo materials of Sample Nos. 701 and 702 of Example 24 had a relative density of 99.9% or more. It has been confirmed that the Mo materials of Sample Nos. 704, 705 and 601 as Comparative Examples had a relative density including a portion less than 99.5%.
Example 25In Example 25, Mo materials for Sample Nos. 801 to 805 and 602 were produced in the same manner as in Example 22 except that HIP was not additionally performed. Table 44 shows a content in mass of each component according to weighed value of raw material powder and content in mass of each component according to a measured value of a composition of each Mo material in Example 25. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 45.
As shown in Table 45, it has been confirmed that the Mo materials of Sample Nos. 801 to 803 of Example 25 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 801 and 802 of Example 25 had a relative density of 99.9% or more. It has been confirmed that the Mo materials of Sample Nos. 804, 805 and 602 of as Comparative Examples had a relative density including a portion less than 99.5%.
Example 26In Example 26, Mo materials for Sample Nos. 901 to 905 and 603 were produced in the same manner as in Example 23 except that HIP was not additionally performed. Table 46 shows a content in mass of each component according to a weighed value of raw material powder and a content in mass of each component according to a measured value of a composition of each Mo material in Example 26. In the same manner as in Example 1, test pieces were cut out and subjected to measurement of relative density. A result thereof is shown in Table 47.
As shown in Table 47, it has been confirmed that the Mo materials of Sample Nos. 901 to 903 of Example 26 had a relative density of 99.5% or more. It has been confirmed that the Mo materials of Sample Nos. 901 and 902 of Example 26 had a relative density of 99.9% or more. It has been confirmed that the Mo materials of Sample Nos. 904, 905, 603 as Comparative Examples had a relative density including a portion less than 99.5%.
From the results of Examples 24 to 26, it has been confirmed that a Mo material that contains 0.3% by mass or more and 1.5% by mass or less of titanium, 0.03% by mass or more and 0.1% by mass or less of zirconium, and 0.01% by mass or more and 0.3% by mass or less of carbon, with a balance composed of molybdenum and unavoidable impurity, can also have a relative density of 99.5% or more, and furthermore, can also have a relative density of 99.9% or more.
It should be understood that the embodiments and examples disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the appended claims rather than by the embodiments described above, and is intended to include all modifications within the scope and meaning equivalent to the claims.
REFERENCE SIGNS LIST1 front end, 2 center, 3 rear end, 4-6 location, 10 raw material powder, 21 capsule, 22 lid, 23 pipe, 24 seal portion, 25 tip.
Claims
1. A molybdenum material having a diameter of 75 mm or more and a length of 250 mm or more, and having a relative density of 99.5% or more.
2. The molybdenum material according to claim 1, wherein the relative density is 99.9% or more.
3. The molybdenum material according to claim 1, that contains 99.9% by mass or more of molybdenum.
4. The molybdenum material according to claim 1, that contains 0.3% by mass or more and 1.5% by mass or less of titanium, 0.03% by mass or more and 0.1% by mass or less of zirconium, and 0.01% by mass or more and 0.3% by mass or less of carbon, with a balance composed of molybdenum and unavoidable impurity.
5. A method for manufacturing a molybdenum material, comprising:
- (1) preparing a first core alloy having an outer diameter of 40 mm or less by hot isostatic pressing;
- (2) disposing the first core alloy in a tube having a diameter larger than that of the first core alloy;
- (3) disposing molybdenum powder in the tube around the first core alloy and subsequently compressing the tube by hot isostatic pressing; (4) removing the compressed tube to form a second core alloy having a diameter larger than that of the first core alloy; and repeating the steps (2) to (4) to obtain a molybdenum material according to claim 1.
Type: Application
Filed: Mar 20, 2019
Publication Date: Jan 14, 2021
Applicant: A.L.M.T. Corp. (Tokyo)
Inventors: Akihiro YOSHIDA (Toyama-shi), Takanori KADOKURA (Toyama-shi), Tomohiro TAKIDA (Toyama-shi)
Application Number: 16/981,440
