JP6736777B2 - Molybdenum material and manufacturing method thereof - Google Patents

Description

This invention relates to a molybdenum material. This application claims priority based on Japanese Patent Application No. 2018-063888, which is a Japanese patent application filed on March 29, 2018. All contents described in the Japanese patent application are incorporated herein by reference.

Conventionally, molybdenum materials have been disclosed in, for example, Japanese Patent Laid-Open Nos. 2007-169789 and 2007-113033.

JP, 2007-169789, A JP 2007-113033 A

A 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 the relative density of the molybdenum material is 99.5% or more.

FIG. 1 is a cross-sectional view showing molybdenum powder filled in a container. FIG. 2 is a cross-sectional view showing a HIP-compressed container and molybdenum powder. FIG. 3 is a cross-sectional view of the molybdenum sintered body taken out from the container. FIG. 4 is a perspective view of a disk cut out from a molybdenum material. FIG. 5 is a perspective view showing a portion where the test piece is taken out from the disc.

[Problems to be solved by the present disclosure]
With the conventional molybdenum material, it was not possible to obtain a large volume.
Therefore, the present invention has been made to solve the above problems.

[Description of Embodiments of the Present Invention]
(1) Outline of Embodiment A 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 the relative density of the molybdenum material is 99.5% or more.

The relative density of the molybdenum material is preferably 99.9% or more.

In one embodiment of the present invention, the molybdenum material contains molybdenum in an amount of 99.9% by mass or more.

In one embodiment of the present invention, the molybdenum material is such that titanium is 0.3 mass% or more and 1.5 mass% or less, zirconium is 0.03 mass% or more and 0.1 mass% or less, and carbon is 0.01 mass%. % Or more and 0.3 mass% or less, and the balance is molybdenum and inevitable impurities.

The method for producing a molybdenum material is preferably a step (1) of producing a first core alloy having an outer diameter of 40 mm or less by using a hot isostatic pressing method, and a tube having a diameter larger than that of the first core alloy. A step (2) of arranging the first core alloy, a step (3) of arranging molybdenum powder in the tube around the first core alloy and then compressing it by a hot isostatic pressing method, and a tube after compression Is removed to form a second core alloy having a diameter larger than that of the first core alloy, and a step of repeating steps (2) to (4).

(2) Comparison with Prior Document In Patent Document 1, in the Examples, W powder having a particle size of 4.1 μm is pressed at a pressure of 200 MPa by using CIP (Cold Isostatic Pressing). By pressing and sintering in a hydrogen atmosphere at a temperature of 2250° C., a sintered rod having a relative density of 92% is obtained. In the next step, by pressing using HIP (Hot Isostatic Pressing (hot isostatic pressing)) at a temperature of 1750° C. and a pressure of 195 MPa for 3 hours, sintering with a relative density of 97.9% is performed. I have a rod. By subjecting this rod to a forming process with a forming degree of 67% using a radial forging machine, a tungsten rod with an average relative density of the entire rod of 99.66% and a relative core density of 99.63% was obtained. There is. After annealing this rod at a temperature of 1800° C. for 4 hours, the crystal grain size, that is, the average number of crystal grains per 1 mm ² is about 800 at the center of the rod and about 850 at the periphery.

In Patent Document 2, in an example, a soft iron can is filled with Mo powder having an average particle size of 45 μm or less, and then vacuum degassing is performed while heating at a temperature of 400° C. to seal the can. This soft iron can is pressed with HIP at a temperature of 1250° C. and a pressure of 148 MPa for 5 hours to obtain a Mo sintered body having a relative density of 99.8%. This Mo sintered body is cut into a plate shape having a length of 380 mm, a width of 110 mm, and a thickness of 8.1 mm, heated to 700° C., and then rolled to a thickness of 4.6 mm in a temperature range not lower than 200° C. Plastic working by.

The manufacturing methods described in Patent Documents 1 and 2 cannot meet customer demands for efficient manufacturing of Mo materials. In addition, it is impossible to manufacture a large volume of Mo material having a small density unevenness, which is required for the demand for increasing the size and increasing the strength of parts such as furnace materials.

When a Mo material is manufactured by powder metallurgy, for example, sintering after pressing, or pressing using HIP, the sintered alloy tends to have a low internal density and a high outer circumference. Further, the density unevenness between the inside and the outside increases as the product size increases. As a method of correcting this density unevenness, when performing plastic working involving a large amount of deformation, it was necessary to apply a large amount of hot stress to the Mo material.

For the above reasons, in order to increase the diameter of the Mo material, it is necessary to upsize the preheating furnace and the hot plastic working apparatus. Further, unless the Mo material is quickly conveyed from the non-oxidizing atmosphere in the preheating furnace to the air atmosphere in which the plastic working apparatus is placed, the temperature of the Mo material is lowered and the Mo material is cracked during the plastic working. The problem arises. However, there is a problem that the equipment becomes larger and the Mo material becomes larger and the weight increases, which makes it difficult to quickly convey the Mo material.

In the present disclosure, as shown in the embodiment by way of example, by making a Mo sintered body stepwise from the center side to the outer peripheral side and increasing the overall density, a diameter that has never existed before is obtained. A rod-shaped Mo material of 75 mm or more was obtained. By using this Mo material, a large number of parts having a uniform density can be obtained. When the Mo material is used as a target, since the density of the Mo material is uniform, it is possible to uniformly wear and obtain a large number of wafers having good wear characteristics. When the Mo material is used for a heater, it is possible to obtain a large number of heating elements that have a small variation in electric resistance and are hard to break. When the Mo material is used for a furnace material, a large number of members having a uniform material strength can be obtained. When the Mo material is used for an electrode for resistance welding, the density of the Mo material is uniform, so that a large number of electrodes with small fluctuations in joining conditions can be obtained.

(3) Dimensions of Mo material The diameter of the Mo material is 75 mm or more. Moreover, the diameter of the Mo material is preferably 300 mm or less. Since the Mo material has a diameter of 75 mm or more, the Mo material can be used for parts having a large volume, for example, the above-mentioned 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.

The Mo material may have any diameter as long as it is 75 mm or more, but from the viewpoint of practical use, it is preferably 300 mm or less. As a method of measuring the diameter of the Mo material, the diameters of arbitrary plural points of the Mo material are measured with a caliper, and the average value of the measured maximum diameter and minimum diameter is taken as the diameter of the Mo material.

The variation in the diameter of the Mo material is preferably within 20%. When the black skin formed on the outer periphery of the Mo material is removed by machining, if the variation in the diameter of the Mo material exceeds 20%, it may be difficult to remove the black skin. It should be noted that "may be" means that such a situation may occur, but does not mean that such a situation will occur with a high probability.

The shape of the Mo material is not limited to the cylindrical shape and may be a polygonal shape. When the Mo material has a polygonal shape, the diameter of the virtual circle having the largest area inside the polygon is the diameter of the Mo material.

Further, the density of the Mo material is measured with respect to the portion within the virtual circle having the above-mentioned maximum area.
The length of the Mo material is 250 mm or more. The length of the Mo material is preferably 1500 mm or less. When the length of the Mo material is 250 mm or more, for example, when forming the above-mentioned parts from the Mo material, a large number of parts can be taken from the Mo material at one time. If the length of the Mo material is less than 250 mm, the take-off height of parts may be small, and production efficiency may be deteriorated. Further, the density of the central portion of the Mo material can be increased by the conventional method without using the steps in this embodiment. The Mo material may have any length as long as it is 250 mm or more, but it is preferably 1500 mm or less from the viewpoint of practical use.

The relative density inside the Mo material is 99.5% or more. When the relative density inside the Mo material is 99.5% or more, it is possible to reduce the density difference between the parts when a large number of the above parts are taken from each part of the Mo material. Preferably, the relative density inside the Mo material is 99.9% or more. More preferably, the relative density inside the Mo material is 100%.

When the relative density inside the Mo material is less than 99.5%, the density unevenness between the components is large, and the component characteristics may vary.

The method for measuring the relative density inside the Mo material is as follows. In the following, the relative density of the Mo material may be simply referred to as the relative density. With respect to the obtained rod-shaped Mo material, a disk having a thickness of 30 mm is cut out from a total of three locations on both ends and the center of the Mo material in the longitudinal direction. As an evaluation site, a test piece of 10×10×10 mm was cut out from a total of three places, in the diametrical direction of each cut-out disk, in the vicinity of the surface, the center, and the intermediate position between the vicinity of the surface and the center, and the Archimedes method was applied. Then, the relative density of the Mo material is measured. Specifically, the relative density of the Mo material is calculated from the composition of the Mo material, the true 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 the volume of the water surface rise when the test piece is placed in a beaker containing water. The mass of the test piece is measured by an electronic balance.

The relative density of the Mo material is calculated by the following formula.
Relative density of Mo material=(mass of test piece/volume of test piece)/true density The true density is determined by the composition of the Mo material.

The Mo material may contain 99.9 mass% or more of Mo. In this case, the ma workability and plastic workability of the Mo material can be improved as compared with the Mo material having a Mo content of less than 99.9% by mass.

As for the Mo material, Ti is 0.3% by mass or more and 1.5% by mass or less, Zr is 0.03% by mass or more and 0.1% by mass or less, and C is 0.01% by mass or more and 0.3% by mass or less. It may be contained, and the balance may be composed of Mo, unavoidable impurities and unavoidable gas impurities. In this case, the mechanical strength of the Mo material can be increased as compared with the Mo material having a Mo content of 99.9 mass% or more.

The unavoidable impurities include, for example, at least one of Al, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, Si, Na, K and W. The unavoidable gas impurities include, for example, at least one of N and O. The mass content of the total amount of unavoidable impurities in the Mo material is preferably 0.1 mass% or less. The mass content of the total amount of unavoidable gas impurities in the Mo material is preferably 0.01 mass% or less.

When the mass content of Ti in the Mo material exceeds 1.5 mass %, there is a possibility that a Mo material having a sufficient density cannot be obtained. If the mass content of Ti in the Mo material is less than 0.3% by mass, it may not be possible to obtain a Mo material having a strength exceeding pure Mo. The pure Mo is a molybdenum material having a Mo mass content of 99.9 mass% or more.

If the mass content of Zr in the Mo material exceeds 0.1% by mass, there is a possibility that a Mo material having a sufficient density cannot be obtained. If the mass content of Zr in the Mo material is less than 0.03 mass %, it may not be possible to obtain a Mo material having a strength exceeding pure Mo.

If the mass content of C in the Mo material exceeds 0.3 mass %, it may not be possible to obtain a Mo material having a sufficient density. When the mass content of C in the Mo material is less than 0.01% by mass, it may not be possible to obtain a Mo material having a strength exceeding pure Mo.

If the mass content of the total amount of unavoidable impurities in the Mo material exceeds 0.1% by mass, it may not be possible to obtain a Mo material having sufficient density and stable properties. If the mass content of the total amount of unavoidable gas impurities in the Mo material exceeds 0.01% by mass, it may not be possible to obtain a Mo material having sufficient density and stable characteristics.

The method for measuring the composition of the metal element is ICP (inductively coupled plasma emission spectroscopy) of JIS H1404 (2001). The measuring device for metal elements by ICP is ICPS-8100 manufactured by Shimadzu Corporation. The measuring device for C is EMIA-920-V2 manufactured by Horiba. The measuring device for O and N is ON-836 manufactured by LECO.

The breaking strength of the Mo material at room temperature is preferably 400 MPa or more, and the breaking strength of the Mo material at 1000° C. is preferably 50 MPa or more. If these breaking strengths are not satisfied, for example, when the Mo material is used for a furnace material, it may be deformed during use.

Included in the Mo material, it is preferable that the number of diameter 30μm or more holes 0 / cm ^2, the number of holes having a diameter of less than 30μm is 200 / cm ² or less.

The method for measuring the number of holes contained in the Mo material is as follows. With respect to the obtained rod-shaped Mo material, a disk-shaped sample having a thickness of 15 mm and a diameter of 10 mm is cut out from each position in the diameter direction at the center and in the vicinity of the surface. The cut surface of the sample is polished so that the surface roughness (Rz) of the polished surface is 0.2 μm or less. As a polishing method, for example, the cut surface is polished with No. 180 to No. 2000 water-resistant paper, and then buffed with a diamond suspension having a particle size of 1 μm to 3 μm.

The polished surface of the sample is observed using a stereoscopic microscope SZ40 manufactured by Olympus to confirm the position of the hole having the maximum diameter. The extraction range including the position of the pore with the largest diameter on the polished surface of the sample is observed at 1000 times using a microscope VHX-6000 manufactured by Keyence, and the maximum diameter of the pore is measured. The maximum diameter of the holes is the diameter of the inscribed circle of the observed holes. The extraction 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, while expanding the extraction range by 100 times, all those having a contrast different from that of the matrix are determined as voids, extracted, and subjected to contamination analysis to measure the number of holes. At this time, the number of pores is measured in a state where the extraction parameters are adjusted so that the maximum diameter of the pores matches the measurement value when observed at 1000 times.

When the Mo material contains pores with a diameter of 30 μm or more, and when the number of pores with a diameter of less than 30 μm exceeds 200/cm ² , for example, when the Mo material is used for a target application, sputtering is performed. There is a possibility that the variation in the thickness of the film formed by will increase.

[Detailed Description of Embodiments of the Present Invention]
Hereinafter, the present invention will be described based on examples.

(Example 1)
(1) Manufacturing Step of Mo Sintered Body as Mo Material (1-1) Raw Material As a raw material, Mo powder having an FSSS particle size of 4.0 μm by the Fischer method was used. The Fsss particle size is preferably 3 μm or more and 10 μm or less. If the Fsss particle size exceeds 10 μm, the density of the Mo sintered body may not increase as a whole. If the Fsss particle size is less than 3 μm, the density of the central portion of the Mo sintered body may not increase. Pure Mo powder was used as the raw material powder.

(1-2) Core Alloy In Example 1, Mo materials of sample numbers 1 to 3 and 101 shown in Table 1 were produced.

In order to obtain core sintered bodies of sample numbers 1 to 3 and 101 shown in Table 1, four capsules 21 which are the tubes shown in FIG. 1 were prepared. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 2000 mm. Regarding the inner diameter of the capsule 21, the sample number 1 was 43 mm, the sample number 2 was 60 mm, the sample number 3 was 77 mm, and the sample number 101 was 135 mm. The capsule 21 is composed of a mild steel can. However, the material of the capsule 21 is not limited to mild steel.

After filling the raw material powder 10 of Mo into the capsule 21 so that the bulk density is 4.2 g/cm ³ , a lid 22 to which a pipe 23 for high temperature degassing is welded is attached to the capsule 21 and TIG (Tungsten Inert Gas). Welded. A hose connected to the oil rotary pump and the oil diffusion pump was attached to the tip 25 of the pipe 23.

The container in which the lid 22 was welded to the capsule 21 was placed in an atmospheric furnace maintained at a temperature of 500° C., and a vacuum was drawn using an oil rotary pump and an oil diffusion pump, and the internal pressure of the container was changed from normal pressure to 1×10 ^{− The} pressure was reduced to ³ Pa. By taking out the container that has been degassed at high temperature in this way, crushing the pipe 23 at the position where the sealing portion 24 is provided, separating the pipe at the crushed portion, and TIG welding the end portion of the cut pipe. It sealed and provided the sealing part 24.

The thickness of the mild steel can is preferably 3 mm or more and 20 mm or less. If the thickness of the mild steel can exceeds 20 mm, the density of the Mo alloy may not increase during pressure sintering. If the thickness of the mild steel can is less than 3 mm, the capsule 21 may be broken during pressure sintering. In the capsule 21, the outer peripheral portion and the bottom portion may be integrally formed. When the capsule 21 has a large size, the outer peripheral portion and the bottom portion, which are formed of different members, may be joined to each other by TIG welding. Good. As the lid 22, for example, a plate material having the same thickness as the capsule 21 can be used.

The temperature in the furnace at the time of high-temperature degassing is preferably 400°C or higher and 500°C or lower. If the furnace temperature exceeds 500° C., the Mo powder may be oxidized when the degree of vacuum in the container is low. If the temperature in the furnace is lower than 400° C., the gas components and the like adsorbed on the Mo powder cannot be sufficiently degassed, and voids may occur inside the Mo alloy.

The time for high-temperature degassing is preferably 1 hour or more and 5 hours or less after the temperature of the capsule 21 becomes the same as the furnace temperature. After the high temperature degassing time exceeds 5 hours, the properties of the Mo alloy are not improved, and thus the high temperature degassing for more than 5 hours deteriorates the economical efficiency. When the time of high-temperature degassing is less than 1 hour, gas components adsorbed on the Mo powder cannot be sufficiently degassed, and voids may occur inside the Mo alloy.

The ultimate pressure in the container during high temperature degassing is preferably less than 1×10 ⁻² Pa. When the ultimate pressure in the container is 1×10 ⁻² Pa or more, deaeration is not sufficiently performed, and the density of the Mo alloy may be difficult to increase during pressing with HIP.

The bulk density of the Mo powder in the container is preferably 2.5 g/cm ³ or more and 5.0 g/cm ³ or less. When the bulk density of the Mo powder exceeds 5.0 g/cm ³ , the gas components and the like adsorbed on the Mo powder cannot be sufficiently degassed, and the density of the Mo alloy may be difficult to increase. When the bulk density of the Mo powder is less than 2.5 g/cm ³ , the shrinkage rate of the Mo alloy during pressing with HIP becomes too large, and the Mo sintered body having a target shape may not be obtained. More preferably, the bulk density of the Mo powder in the container is 3.5 g/cm ³ or more and 4.5 g/cm ³ or less.

(1-3) Sintering The sealed container was placed in a furnace of a hot isostatic press, and pressure sintering was performed by HIP at a temperature of 1280° C. and a pressure of 147 MPa for 5 hours. .. Hereinafter, pressure sintering by HIP may be simply referred to as HIP. As shown in FIG. 2, HIP reduced the volume in the container.

After pressure sintering, the container was removed by machining to obtain a core sintered body 11 which is the first core alloy of sample numbers 1 to 3 and 101 as shown in FIG. The size of the core sintered body 11 is as shown in Table 1.

When the relative density of the core sintered body 11 was measured by the Archimedes method, it was 99.5% or more and 99.9% or less in the central portion in the diametrical direction and 100% in the portion other than the central portion. The heating temperature during HIP is preferably 1000°C or higher and 1350°C or lower. When the heating temperature exceeds 1350° C., the temperature becomes close to the melting point of the mild steel forming the capsule 21, and the capsule 21 may be broken during HIP. If the heating temperature is less than 1000°C, the density of the Mo alloy may not increase during HIP.

The ultimate pressure in the container during HIP is preferably 98 MPa or more and 250 MPa or less. After the ultimate pressure in the container exceeds 250 MPa, the density of the Mo alloy does not increase. Therefore, if the pressure exceeds 250 MPa, the economical efficiency deteriorates. If the ultimate pressure in the container is less than 98 MPa, the density of the Mo alloy may not increase. HIP is preferably performed for 1 hour or more and 10 hours or less. After the HIP application time exceeds 10 hours, the density of the Mo alloy does not increase, so that the HIP application for more than 10 hours deteriorates the economical efficiency. If the HIP time is less than 1 hour, the density of the Mo alloy may not increase.

The machining allowance of the Mo alloy when removing the mild steel can of the container is preferably 3 mm or more and 10 mm or less. If the machining allowance of the Mo alloy exceeds 10 mm, the machining time becomes long and the yield of the material decreases, so that the economical efficiency deteriorates. If the machining allowance of the Mo alloy is less than 3 mm, the mild steel can may not be completely removed from the Mo alloy.

(1-4) Increasing the diameter In order to increase the diameters of the core sintered bodies 11 of sample numbers 1 to 3 in Table 1, three mild steel can capsules 21 shown in FIG. 1 were prepared. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 1600 mm. Regarding the inner diameter of the capsule 21, the sample number 1 was 80 mm, the sample number 2 was 90 mm, and the sample number 3 was 100 mm. The core sintered body 11 was arranged in the center of the capsule 21, and the raw material described in the column of “(1-1) Raw material” was filled between the capsule 21 and the core sintered body 11. According to the process described in the column of "(1-2) Core alloy", high temperature degassing was performed at a temperature of 400°C, and the container was sealed.

Next, after performing pressure sintering by HIP as described in the column of "(1-3) Sintering", the container was removed by machining. As a result, Mo sintered bodies, which are the second core alloys of sample numbers 1 to 3 having the “diameter” and the “length” in the “first time” column of Table 1, were obtained.

In order to further increase the diameter of the obtained Mo sintered body, three mild steel can capsules 21 shown in FIG. 1 were prepared. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 1600 mm. Regarding the inner diameter of the capsule 21, the sample number 1 was 102 mm, the sample number 2 was 95 mm, and the sample number 3 was 88 mm. The Mo sintered body was arranged at the center of the capsule 21, and the raw material described in the column “(1-1) Raw material” was filled between the capsule 21 and the core sintered body 11. According to the process described in the column of "(1-2) Core alloy", high temperature degassing was performed at a temperature of 400°C, and the container was sealed.

Next, after performing pressure sintering by HIP as described in the column of "(1-3) Sintering", the container was removed by machining. As a result, Mo sintered compacts, which are Mo raw materials of sample numbers 1 to 3, having the “diameter” and the “length” in the “second time” column of Table 1 were obtained.

(2) Evaluation of Mo material For each rod-shaped Mo material of sample numbers 1 to 3 and 101 having a diameter of 75 mm and a length of 1500 mm obtained by the above process, the front end 1, the center 2 and the rear are shown in FIG. At the end 3, a disk having a thickness L1 of 30 mm was cut out. As shown in FIG. 5, as an evaluation place, a test piece was cut out from each of a peripheral position 4, a central position 6, and a position 5 between the peripheral and the center in the diametrical direction of each of the cut out disks. And the relative density was measured. The results are shown in Table 1.

As shown in Table 1, it was confirmed that the relative density of the Mo material in the sample numbers 1 to 3 of Example 1 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 1 and 2 of Example 1 was 99.9% or more. It was confirmed that the relative density of the Mo material in sample No. 101 of the comparative example contained less than 99.5%.

(Example 2)
In Example 2, a core sintered body 11 was prepared in the same manner as in Example 1 except that the length was 1000 mm, and HIP was added twice to the core sintered body 11 to increase the diameter. , Mo materials of sample numbers 4 to 6 were produced. In the comparative example, a Mo material of sample number 102 was prepared in the same manner as sample number 101 except that the length was 1000 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 2.

As shown in Table 2, it was confirmed that the relative density of the Mo material in the sample numbers 4 to 6 of Example 2 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 4 and 5 of Example 2 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 102 of the comparative example contained less than 99.5%.

(Example 3)
In Example 3, a core sintered body 11 was prepared in the same manner as in Example 1 except that the length was 500 mm, and HIP was added twice to the core sintered body 11 to increase the diameter. , Mo materials of sample numbers 7 to 9 were produced. In the comparative example, a Mo material of sample number 103 was manufactured in the same manner as sample number 101 except that the length was 500 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 3.

As shown in Table 3, it was confirmed that the relative density of the Mo material in the sample numbers 7 to 9 of Example 3 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 7 and 8 of Example 3 was 99.9% or more. It was confirmed that the relative density of the Mo material in sample No. 103 of the comparative example contained less than 99.5%.

(Example 4)
In Example 4, a core sintered body 11 was prepared in the same manner as in Example 1 except that the length was 250 mm, and HIP was added twice to the core sintered body 11 to increase the diameter. , Mo materials of sample numbers 10 to 12 were produced. In the comparative example, a Mo material of sample number 104 was manufactured in the same manner as sample number 101 except that the length was 250 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 4.

As shown in Table 4, it was confirmed that the relative density of the Mo material in the sample numbers 10 to 12 of Example 4 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 10 and 11 of Example 4 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 104 of the comparative example contained less than 99.5%.

(Example 5)
In Example 5, in order to obtain the core sintered bodies 11 of sample numbers 13 to 15, three capsules 21 of mild steel can shown in FIG. 1 were prepared. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 2000 mm. Regarding the inner diameter of the capsule 21, the sample number 13 was 43 mm, the sample number 14 was 60 mm, and the sample number 15 was 77 mm. A core sintered body 11 was prepared in the same manner as in Example 1, and HIP was added to the core sintered body 11 twice or three times to increase the diameter to 100 mm, and the sample numbers 13 to 13 were measured. 15 Mo materials were produced. In the comparative example, a Mo material of sample number 105 was prepared in the same manner as sample number 101 except that the diameter was 100 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 5.

As shown in Table 5, it was confirmed that the relative density of the Mo material in sample numbers 13 to 15 of Example 5 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 13 and 14 of Example 5 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 105 of the comparative example contained less than 99.5%.

(Example 6)
In Example 6, the core sintered body 11 was prepared in the same manner as in Example 5 except that the length was 1000 mm, and the HIP was applied to the core sintered body 11 twice or three times. The Mo material of sample numbers 16 to 18 was produced by sizing. In the comparative example, a Mo material of Sample No. 106 was prepared in the same manner as Sample No. 105 except that the length was 1000 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 6.

As shown in Table 6, it was confirmed that the relative density of the Mo material in the sample numbers 16 to 18 of Example 6 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 16 and 17 of Example 6 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 106 of the comparative example contained less than 99.5%.

(Example 7)
In Example 7, the core sintered body 11 was prepared in the same manner as in Example 5 except that the length was 500 mm, and HIP was added to the core sintered body 11 twice or three times. After being sized, Mo materials of sample numbers 19 to 21 were produced. In the comparative example, a Mo material of sample number 107 was manufactured in the same manner as sample number 105 except that the length was 500 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 7.

As shown in Table 7, it was confirmed that the relative density of the Mo material in the sample numbers 19 to 21 of Example 7 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 19 and 20 of Example 7 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 107 of the comparative example contained less than 99.5%.

(Example 8)
In Example 8, a core sintered body 11 was prepared in the same manner as in Example 5 except that the length was 250 mm, and HIP was added to the core sintered body 11 twice or three times. After being sized, Mo materials of sample numbers 22 to 24 were produced. In the comparative example, a Mo material of sample number 108 was manufactured in the same manner as sample number 105 except that the length was 250 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 8.

As shown in Table 8, it was confirmed that the relative density of the Mo material in the sample numbers 22 to 24 of Example 8 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 22 and 23 of Example 8 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 108 of the comparative example contained less than 99.5%.

(Example 9)
In Example 9, in order to obtain the core sintered bodies 11 of sample numbers 25 to 27, three capsules 21 of a mild steel can shown in FIG. 1 were prepared. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 2000 mm. Regarding the inner diameter of the capsule 21, the sample number 25 was 43 mm, the sample number 26 was 60 mm, and the sample number 27 was 77 mm. A core sintered body 11 was prepared in the same manner as in Example 1, and HIP was additionally applied to the core sintered body 11 four times or five times to increase the diameter to 150 mm. 27 Mo materials were produced. In the comparative example, a Mo material of Sample No. 109 was manufactured in the same manner as Sample No. 101 except that the diameter was 150 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 9 and 10.

As shown in Table 10, it was confirmed that the relative density of the Mo material in the sample numbers 25 to 27 of Example 9 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 25 and 26 of Example 9 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 109 of the comparative example contained less than 99.5%.

(Example 10)
In Example 10, a core sintered body 11 was prepared in the same manner as in Example 9 except that the length was 1000 mm, and HIP was added to the core sintered body 11 four times or five times. After being sized, Mo materials of sample numbers 28 to 30 were produced. In the comparative example, a Mo material of sample number 110 was manufactured in the same manner as sample number 109 except that the length was 1000 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 11 and 12.

As shown in Table 12, it was confirmed that the relative density of the Mo material in the sample numbers 28 to 30 of Example 10 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 28 and 29 of Example 10 was 99.9% or more. It was confirmed that the relative density of the Mo material in sample No. 110 of the comparative example contained less than 99.5%.

(Example 11)
In Example 11, a core sintered body 11 was prepared in the same manner as in Example 9 except that the length was 500 mm, and HIP was added to the core sintered body 11 four times or five times. After being sized, Mo materials of sample numbers 31 to 33 were produced. In the comparative example, a Mo material of sample number 111 was manufactured in the same manner as sample number 109 except that the length was 500 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 13 and 14.

As shown in Table 14, it was confirmed that the relative density of the Mo material in the sample numbers 31 to 33 of Example 11 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 31 and 32 of Example 11 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 111 of the comparative example contained less than 99.5%.

(Example 12)
In Example 12, the core sintered body 11 was manufactured in the same manner as in Example 9 except that the length was 250 mm, and HIP was added to the core sintered body 11 four or five times. After being sized, Mo materials of sample numbers 34 to 36 were produced. In the comparative example, a Mo material of sample number 112 was prepared in the same manner as sample number 109 except that the length was 250 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 15 and 16.

As shown in Table 16, it was confirmed that the relative density of the Mo material in the sample numbers 34 to 36 of Example 12 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 34 and 35 of Example 12 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 112 of the comparative example contained less than 99.5%.

(Example 13)
In Example 13, three mild steel can capsules 21 shown in FIG. 1 were prepared to obtain core sintered bodies 11 of sample numbers 37 to 39. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 2000 mm. Regarding the inner diameter of the capsule 21, the sample number 37 was 43 mm, the sample number 38 was 60 mm, and the sample number 39 was 77 mm. The core sintered body 11 was prepared in the same manner as in Example 1, and HIP was added to the core sintered body 11 six times or seven times to increase the diameter to 220 mm, and the sample numbers 37 to 37 were measured. 39 Mo materials were produced. In the comparative example, a Mo material of sample number 113 was manufactured in the same manner as sample number 101 except that the diameter was 220 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 17 and 18.

As shown in Table 18, it was confirmed that the relative density of the Mo material in the sample numbers 37 to 39 of Example 13 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 37 and 38 of Example 13 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 113 of the comparative example contained less than 99.5%.

(Example 14)
In Example 14, the core sintered body 11 was prepared in the same manner as in Example 13 except that the length was 1000 mm, and the HIP was added to the core sintered body 11 6 times or 7 times. After being sized, Mo materials of sample numbers 40 to 42 were produced. In the comparative example, a Mo material of sample number 110 was manufactured in the same manner as sample number 113 except that the length was 1000 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 19 and 20.

As shown in Table 20, it was confirmed that the relative density of the Mo material in the sample numbers 40 to 42 of Example 14 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 40 and 41 of Example 14 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 114 of the comparative example contained less than 99.5%.

(Example 15)
In Example 15, the core sintered body 11 was prepared in the same manner as in Example 13 except that the length was 500 mm, and the HIP was added to the core sintered body 11 6 times or 7 times. After being sized, Mo materials of sample numbers 43 to 45 were produced. In the comparative example, a Mo material of sample number 115 was manufactured in the same manner as sample number 113 except that the length was 500 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 21 and 22.

As shown in Table 22, it was confirmed that the relative density of the Mo material in the sample numbers 43 to 45 of Example 15 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 43 and 44 of Example 15 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 115 of the comparative example contained less than 99.5%.

(Example 16)
In Example 16, the core sintered body 11 was manufactured in the same manner as in Example 13 except that the length was 250 mm, and HIP was added to the core sintered body 11 6 times or 7 times to increase the size. After being sized, Mo materials of sample numbers 46 to 48 were produced. In the comparative example, a Mo material of sample number 116 was manufactured in the same manner as sample number 113 except that the length was 250 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 23 and 24.

As shown in Table 24, it was confirmed that the relative density of the Mo material in the sample numbers 46 to 48 of Example 16 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 46 and 47 of Example 16 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 116 of the comparative example contained less than 99.5%.

(Example 17)
In Example 17, three capsules 21 of a mild steel can shown in FIG. 1 were prepared in order to obtain the core sintered bodies 11 of sample numbers 49 to 51. The thickness of the capsule 21 was 10 mm, and the length of the capsule 21 was 2000 mm. Regarding the inner diameter of the capsule 21, the sample number 49 was 43 mm, the sample number 50 was 60 mm, and the sample number 51 was 77 mm. A core sintered body 11 was prepared in the same manner as in Example 1, and HIP was additionally applied to the core sintered body 11 9 times or 10 times to increase the diameter to 300 mm, and the sample numbers 49 to 51 Mo materials were produced. In the comparative example, a Mo material of Sample No. 117 was prepared in the same manner as Sample No. 101 except that the diameter was 300 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 25 and 26.

As shown in Table 26, it was confirmed that the relative density of the Mo material in the sample numbers 49 to 51 of Example 17 was 99.6% or more. It was confirmed that the relative density of the Mo material in the sample numbers 49 and 50 of Example 17 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 117 of the comparative example contained less than 99.5%.

(Example 18)
In Example 18, the core sintered body 11 was prepared in the same manner as in Example 17 except that the length was 1000 mm, and HIP was added 9 times or 10 times to the core sintered body 11 to increase the size. After being sized, Mo materials of sample numbers 52 to 54 were produced. In the comparative example, a Mo material of sample number 118 was manufactured in the same manner as sample number 117 except that the length was 1000 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 27 and 28.

As shown in Table 27, it was confirmed that the relative density of the Mo material in the sample numbers 52 to 54 of Example 18 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 52 and 53 of Example 18 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample number 118 of the comparative example contained less than 99.5%.

(Example 19)
In Example 19, the core sintered body 11 was prepared in the same manner as in Example 17 except that the length was 500 mm, and the HIP was added 9 times or 10 times to the core sintered body 11 to increase the size. After being sized, Mo materials of sample numbers 55 to 57 were produced. In the comparative example, a Mo material of sample number 119 was manufactured in the same manner as sample number 117 except that the length was 500 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 29 and 30.

As shown in Table 30, it was confirmed that the relative density of the Mo material in the sample numbers 55 to 57 of Example 19 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 55 and 56 of Example 19 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 119 of the comparative example contained less than 99.5%.

(Example 20)
In Example 20, the core sintered body 11 was manufactured in the same manner as in Example 17 except that the length was 250 mm, and HIP was added to the core sintered body 11 9 times or 10 times to increase the size. After being sized, Mo materials of sample numbers 58 to 60 were produced. In the comparative example, a Mo material of sample number 120 was manufactured in the same manner as sample number 117 except that the length was 250 mm. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 31 and Table 32.

As shown in Table 32, it was confirmed that the relative density of the Mo material in the sample numbers 58 to 60 of Example 20 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 58 and 59 of Example 20 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 120 of the comparative example contained less than 99.5%.

From the results of Examples 1 to 20, even when the Mo material contains 99.9 mass% or more of Mo, the relative density of the Mo material can be 99.5% or more. It was confirmed that the relative density of the Mo material could be 99.9% or more.

(Example 21)
In Example 21, as in Example 17, except that the composition of the Mo material was changed by adding the Ti component, the Zr component, and the C component to the Mo component of the raw material, the sample numbers 301 to 303 and 601 were changed. A Mo material was produced. Specifically, a raw material powder was prepared by mixing Mo powder, TiC powder, and ZrC powder. The FSSS particle size of the Mo powder was 4.0 μm. The FSSS particle size of the TiC powder was 2.0 μm. The FSSS particle size of the ZrC powder was 3.0 μm.

The FSSS particle size of the Mo powder is preferably 3 μm or more and 10 μm or less. If the Fsss particle size of the Mo powder exceeds 10 μm, the density of the Mo sintered body may not increase as a whole. If the Fsss particle size of the Mo powder is less than 3 μm, the density of the central portion of the Mo sintered body may not increase. The FSSS particle size of the TiC powder is preferably 1 μm or more and 20 μm or less. If the Fsss particle size of the TiC powder exceeds 20 μm, the density of the Mo sintered body may not increase as a whole. If the Fsss particle size of the TiC powder is less than 1 μm, the density of the central portion of the Mo sintered body may not increase. The FSSS particle size of the ZrC powder is preferably 1 μm or more and 20 μm or less. If the Fsss particle size of the ZrC powder exceeds 20 μm, the density of the Mo sintered body may not increase as a whole. If the Fsss particle size of the ZrC powder is less than 1 μm, the density of the central portion of the Mo sintered body may not increase.

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 the raw material powder. When using TiC powder and ZrC powder, C powder may be mixed with the raw material powder. The FSSS particle size of the C powder is preferably 0.1 μm or more and 10 μm or less. If the Fsss particle size of the C powder exceeds 10 μm, the density of the Mo sintered body may not increase as a whole. If the Fsss particle size of the C powder is less than 0.1 μm, the density of the central portion of the Mo sintered body may not increase. The pure Ti is a titanium material having a Ti mass content of 99.9 mass% or more. The pure Zr is a zirconium material having a Zr mass content of 99.9 mass% or more.

Table 33 shows the mass content of each component based on the weighed value of the raw material powder and the mass content of each component based on the measured composition of the Mo material in Example 21. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 34 and Table 35.

As shown in Table 35, it was confirmed that the relative density of the Mo material in the sample numbers 301 to 303 of Example 21 was 99.6% or more. It was confirmed that the relative density of the Mo material in the sample numbers 301 and 302 of Example 21 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 601 of the comparative example contained less than 99.5%.

(Example 22)
In Example 22, Mo materials of sample numbers 401 to 403 and 602 were produced in the same manner as in Example 21 except for the composition of the Mo material. Table 36 shows the mass content of each component based on the weighed value of the raw material powder and the mass content of each component based on the measured composition of the Mo material in Example 22. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Tables 37 and 38.

As shown in Table 38, it was confirmed that the relative density of the Mo material in the sample numbers 401 to 403 of Example 22 was 99.6% or more. It was confirmed that the relative density of the Mo material in the sample numbers 401 and 402 of Example 22 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample No. 602 of the comparative example contained less than 99.5%.

(Example 23)
In Example 23, Mo materials of sample numbers 501 to 503 and 603 were produced in the same manner as in Example 21 except for the composition of the Mo material. Table 39 shows the mass content of each component based on the weighed value of the raw material powder and the mass content of each component based on the measured composition of the Mo material in Example 23. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 40 and Table 41.

As shown in Table 41, it was confirmed that the relative density of the Mo material in the sample numbers 501 to 503 of Example 23 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 501 and 502 of Example 23 was 99.9% or more. It was confirmed that the relative density of the Mo material in sample No. 603 of the comparative example contained less than 99.5%.

From the results of Examples 21 to 23, the Mo raw material was 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 carbon. Even when the content is 0.01% by mass or more and 0.3% by mass or less, and the balance is molybdenum and unavoidable impurities, the relative density of the Mo material can be 99.5% or more. It was confirmed that the relative density could be 99.9% or more.

(Example 24)
In Example 24, Mo materials of sample numbers 701 to 705 and 601 were produced in the same manner as in Example 21 except that HIP was not added. Table 42 shows the mass content of each component based on the weighed value of the raw material powder and the mass content of each component based on the measured composition of the Mo material in Example 24. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 43.

As shown in Table 43, it was confirmed that the relative density of the Mo material in the sample numbers 701 to 703 of Example 24 was 99.6% or more. It was confirmed that the relative density of the Mo material in the sample numbers 701 and 702 of Example 24 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample numbers 704, 705, and 601 of the comparative example includes a portion of less than 99.5%.

(Example 25)
In Example 25, Mo materials of sample numbers 801 to 805 and 602 were produced in the same manner as in Example 22 except that HIP was not added. Table 44 shows the mass content of each component based on the weighed value of the raw material powder and the mass content of each component based on the measured composition of the Mo material in Example 25. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 45.

As shown in Table 45, it was confirmed that the relative density of the Mo material in the sample numbers 801 to 803 of Example 25 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 801 and 802 of Example 25 was 99.9% or more. It was confirmed that the relative density of the Mo material in the sample numbers 804, 805, and 602 of the comparative example included a portion of less than 99.5%.

(Example 26)
In Example 26, Mo materials of sample numbers 901 to 905 and 603 were produced in the same manner as in Example 23 except that HIP was not added. Table 46 shows the mass content of each component based on the weighed value of the raw material powder and the mass content of each component based on the measured composition of the Mo material in Example 26. In the same manner as in Example 1, the test piece was cut out and the relative density was measured. The results are shown in Table 47.

As shown in Table 47, it was confirmed that the relative density of the Mo material in the sample numbers 901 to 903 of Example 26 was 99.5% or more. It was confirmed that the relative density of the Mo material in the sample numbers 901 and 902 of Example 26 was 99.9% or more. It was confirmed that the relative densities of the Mo materials in sample numbers 904, 905, and 603 of the comparative example included less than 99.5%.

From the results of Examples 24 to 26, the Mo raw 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 carbon. Even when the content is 0.01% by mass or more and 0.3% by mass or less, and the balance is molybdenum and unavoidable impurities, the relative density of the Mo material can be 99.5% or more. It was confirmed that the relative density could be 99.9% or more.

The embodiments and examples disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiments but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 front end, 2 center, 3 rear end, 4 to 6 positions, 10 raw material powder, 21 capsules, 22 lids, 23 pipes, 24 sealing parts, 25 tips.

Claims (4)

Position of the peripheral edge in the diametrical direction of each disc, which is a sintered molybdenum material having a diameter of 75 mm or more and a length of 250 mm or more, and having a thickness of 30 mm cut out at the front end, the center, and the rear end of the molybdenum material. A molybdenum material in which the relative density at all positions is 99.9% or more when the relative density is measured by cutting out the test piece from each of the position at the center and the position between the periphery and the center. The molybdenum raw material according to claim 1, which contains 99.9% by mass or more of molybdenum. It contains titanium in an amount of 0.3% by mass or more and 1.5% by mass or less, zirconium in an amount of 0.03% by mass or more and 0.1% by mass or less, and carbon in an amount of 0.01% by mass or more and 0.3% by mass or less, and the balance. The molybdenum material according to claim 1, wherein the molybdenum and the unavoidable impurities. A step (1) of producing a first core alloy having an outer diameter of 40 mm or less using a hot isostatic pressing method;
Placing the first core alloy in a tube having a diameter larger than that of the first core alloy (2),
Placing molybdenum powder in the tube around the first core alloy and then compressing it by a hot isostatic pressing method (3),
Removing the tube after compression to form a second core alloy having a larger diameter than the first core alloy (4),
A method for producing a molybdenum material, comprising the steps of repeating steps (2) to (4) to obtain the molybdenum material according to any one of claims 1 to 3.

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