Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/05—Metallic powder characterised by the size or surface area of the particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/06—Metallic powder characterised by the shape of the particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/20—Direct sintering or melting
  • B22F10/25—Direct deposition of metal particles, e.g. direct metal deposition [DMD] or laser engineered net shaping [LENS]
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
  • C22C19/03—Alloys based on nickel or cobalt based on nickel
  • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
  • C22C19/03—Alloys based on nickel or cobalt based on nickel
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
  • C22C19/07—Alloys based on nickel or cobalt based on cobalt
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• the present invention relates to a metal powder suitable for metal additive manufacturing.
• the present invention relates to a metal powder suitable for deposition-type metal additive manufacturing.
• metal additive manufacturing has been applied to the production of objects made of metal.
• Representative methods of metal additive manufacturing include the powder bed method (powder bed fusion method) and the deposition method (directed energy deposition method).
• the irradiated areas of the spread metal powder melt and solidify when irradiated with a laser beam or electron beam.
• the metal particles bond together as a result of melting and solidification. Irradiation is selectively performed on parts of the metal powder, and the non-irradiated areas do not melt, and a bonded layer is formed only in the irradiated areas.
• New metal powder is then laid on top of the bonded layer, and the metal powder is irradiated with a laser beam or electron beam. The irradiation causes the metal particles to melt and solidify, forming a new bonded layer. The new bonded layer also bonds with the existing bonded layer.
• Patent Document 1 for an example of an additive manufacturing method using the powder bed method.
• a laser is used as a heat source, and metal powder is sprayed from a nozzle onto the laser focus area, where it is melted and layered.
• Patent Document 2 for an example of an additive manufacturing method using the deposition method.
• metal powder In order to develop powders suitable for metal additive manufacturing, efforts are being made to improve the properties of metal powder, such as laser absorption rate, inclusion concentration, and fluidity.
• the fluidity of metal powder is one of the most important properties from the standpoint of uniformly spreading metal powder in the powder bed method, and of continuously supplying metal powder from a nozzle in the deposition method.
• the method for measuring the fluidity of metal powders is specified in the Japanese Industrial Standards (JIS) Z2502:2020.
• JIS Japanese Industrial Standards
• the fluidity of metal powders is evaluated by measuring the time (s/50g) required for 50g of powder to fall from a funnel containing a sample.
• time s/50g
• a method has also been proposed in which nanoparticles are mixed in to reduce the adhesive force between the particles that make up the metal powder, thereby improving the fluidity of the metal powder (see Patent Document 3).
• the particle size range of metal powders used in the deposition method is 45 to 150 ⁇ m, which is larger than the particle size range of metal powders used in the powder bed method (10 to 45 ⁇ m).
• the metal powder In the deposition method, the metal powder needs to flow by its own weight inside a thin pipe in order to be sprayed from the nozzle, so the fluidity of the metal powder is important. If the fluidity of the metal powder is low, the metal powder may get clogged inside the pipe midway, preventing the powder from being properly supplied to the laser melting area, and the modeling process may be interrupted.
• the evaluation of metal powder fluidity stipulated in the aforementioned JIS Z2502:2020 is a method that involves sampling a small amount of powder (50 g), and therefore is not a method that can actually completely evaluate the fluidity required for the deposition method.
• the inventors investigated the nozzle blockage and found that needle-shaped particles with major axis diameters of about 300 to 800 ⁇ m, as shown in Figure 1, had accumulated in the blockage, and that the nozzle blockage was caused by the accumulation of needle-shaped particles in the powder discharge section due to long-term powder transport.
• the diameter of the nozzle outlet in the powder discharge section is usually the same as the major axis diameter of the needle-shaped particles or slightly larger than the major axis diameter.
• Acicular particles do not occur every time metal powder (e.g., atomized powder) is manufactured, but occur unexpectedly and unintentionally. Basically, by classifying metal powder, most of the acicular particles are sieved out, and most of the acicular particles are removed. Since the proportion of acicular particles is reduced by classification compared to before classification, classification was previously considered sufficient. This is because classification results in a value that does not interfere with the measurement of flow rate (s/50g) specified by JIS.
• the problem that this invention aims to solve is to provide a metal powder that contains a small proportion of acicular particles and is suitable for a deposition-type additive manufacturing device that supplies powder from a nozzle.
• the inventors discovered that one of the reasons why needle-shaped particles in a powder pass through sieve mesh with openings (the length of the space between the lines that make up the mesh) smaller than the long axis diameter during powder classification is that the intense vibrations applied to the powder during powder classification cause the needle-shaped particles in the powder to change position and stand up.
• the short axis diameter of the needle-shaped particle which is smaller than the size of the opening, faces the direction of the mesh of the sieve, causing the needle-shaped particle to pass through the sieve mesh vertically (see Figure 2).
• tapping balls made of urethane rubber are placed on the sieve.
• vibration is suppressed, so the acicular particles do not shake violently compared to when tapping balls are used. Therefore, (1) while using tapping balls as usual, sieving is performed sequentially using a vibrating sieve device using multiple sieves with different opening sizes to obtain powder of a specified particle size, and then (2) the obtained powder is sieved using a vibrating sieve device without using tapping balls or with a reduced number of tapping balls and using a sieve with a slightly larger opening size.
• the inventors have discovered that by not using tapping balls or by drastically reducing the number of tapping balls to suppress the vibrations applied to the powder and thereby suppressing the rising of acicular particles, it is possible to suitably obtain metal powder for additive manufacturing with very few acicular particles after classification through a sieve.
• the present invention provides the following metal powder for additive manufacturing.
• a metal powder for additive manufacturing in which the percentage of particles having an aspect ratio of 0.4 or less and a maximum major axis of 150 ⁇ m or more is 0.30% or less based on the number of all particles constituting the powder.
• the present invention also provides a method for producing metal powder for additive manufacturing, which includes a step of sieving the metal powder obtained by sequentially sieving using a vibrating sieve device using a sieve with large and small openings while using tapping balls as usual, again using a vibrating sieve device with a sieve with large or larger openings without using tapping balls or with a reduced number of tapping balls, to produce metal powder in which the proportion of particles with an aspect ratio of 0.4 or less and a maximum major axis of 150 ⁇ m or more is 0.30% or less of the total number of particles constituting the powder.
• the procedure utilizing the difference in vibration with and without tapping balls makes it possible to efficiently remove acicular particles.
• the metal powder for additive manufacturing of the present invention has excellent long-term fluidity, so when additive manufacturing is performed using the metal powder for additive manufacturing of the present invention, even if additive manufacturing work is continued by supplying powder using a nozzle using a deposition method, the additive manufacturing work can be continued for a long time without the nozzle being clogged with powder midway. Furthermore, when additive manufacturing is performed using the metal powder for additive manufacturing of the present invention, a densely molded body with low porosity can be obtained.
• the maximum value of the maximum major axis of all particles constituting the metal powder for additive manufacturing of the present invention is set to 1000 ⁇ m or less, a densely molded body with even lower porosity can be obtained, stable fluidity can be continuously ensured during manufacturing, and nozzle clogging can be further reduced.
• FIG. 1 is a diagram showing a secondary electron image of acicular particles in a Ni-based alloy powder taken with a scanning electron microscope (SEM).
• 2A and 2B are diagrams for explaining the phenomenon in which upright acicular particles pass through the mesh (slits) of a sieve used for classification, in which (a) is a schematic diagram viewed from above, and (b) is a schematic diagram viewed from the side.
• metal powder of the present invention The metal powder for additive manufacturing of the present invention (hereinafter referred to as "metal powder of the present invention”) will be described below.
• the metal powder of the present invention is a collection of many metal particles.
• the percentage of particles having an aspect ratio of 0.4 or less and a maximum major axis of 150 ⁇ m or more is 0.30% or less based on the number of all particles constituting the metal powder of the present invention.
• particles with an aspect ratio of 0.4 or less and a maximum diameter of 150 ⁇ m or more are called “acicular particles.”
• the "aspect ratio" of a particle means the ratio of the minor axis diameter of the particle to the major axis diameter of the particle (minor axis diameter of the particle/major axis diameter of the particle). The more elongated the particle, the smaller the aspect ratio of the particle.
• the "major axis diameter” and “minor axis diameter” of a particle refer to the length of the major axis and the minor axis, respectively, when the particle is surrounded by two pairs of parallel lines.
• the "maximum major axis" of a particle means the maximum value of the distance between any two points on the contour of the particle.
• the fluidity of metal powders can be confirmed based on JIS Z2502:2020. Specifically, the fluidity of metal powders can be evaluated by opening the orifice at the bottom of a funnel containing a 50 g sample of metal powder and measuring the time (s/50 g) it takes for 50 g of powder to fall from the funnel. This fluidity can be used as a guide to evaluate the ease of handling of metal powders under normal conditions when the nozzle is not clogged.
• the proportion of acicular particles by number is set to 0.30% or less based on the number of all particles constituting the metal powder of the present invention.
• the proportion of acicular particles by number in the metal powder of the present invention is preferably 0.25% or less, more preferably 0.20% or less, and even more preferably 0.15% or less.
• the number proportion of acicular particles in the metal powder of the present invention may be 0.01% or more.
• the number proportion of acicular particles in the metal powder of the present invention may be 0.02% or more.
• the particle count and particle shape analysis can be performed, for example, using an image analyzer Morphologi G3 manufactured by Malvern. Specifically, the process is as follows. First, the metal powder is dispersed on a glass slide, and the particle shapes projected two-dimensionally using an optical microscope are observed for each of the particles constituting the metal powder, and the major axis diameter, minor axis diameter, and maximum major axis diameter of each particle are obtained. Specifically, an image of each particle is taken, and shape parameters are calculated by image analysis to obtain the major axis diameter, minor axis diameter, and maximum major axis diameter of each particle. These procedures can be automatically taken and automatically analyzed by computer software, so that the number and shape of all particles constituting the metal powder can be examined.
• the metal powder to be counted and analyzed for particle shape is determined in relation to the mesh size of the sieve used for classification. In one embodiment, the number of particles is counted and the shape of particles is analyzed for metal powder with a particle size of 45 ⁇ m or more.
• the maximum value of the maximum long diameter of all particles constituting the metal powder of the present invention is preferably 1000 ⁇ m or less.
• the metal powder of the present invention preferably does not contain particles whose maximum long diameter exceeds 1000 ⁇ m. If the maximum long diameter of a particle is too large, it is likely to cause nozzle clogging. Even if the number ratio of acicular particles meets the criteria of the present invention, if even one particle whose maximum long diameter exceeds 1000 ⁇ m is included, it may cause nozzle clogging. Therefore, the maximum value of the maximum long diameter of all particles constituting the metal powder of the present invention is preferably 1000 ⁇ m or less, more preferably 370 ⁇ m or less, and even more preferably 300 ⁇ m or less.
• the lower limit of the maximum value can be adjusted as appropriate.
• the lower limit of the maximum value may be, for example, 100 ⁇ m or more, or 200 ⁇ m or more. Each of these lower limits may be combined with any of the above-mentioned upper limits.
• the median diameter D50 of the metal powder of the present invention is preferably 45 ⁇ m or more and 150 ⁇ m or less, more preferably 55 ⁇ m or more and 120 ⁇ m or less, and even more preferably 60 ⁇ m or more and 90 ⁇ m or less.
• the median diameter D50 of a metal powder is the particle diameter at the point where the cumulative volume is 50% in a volume-based cumulative frequency distribution curve obtained with the total volume of the metal powder being 100%.
• the median diameter D50 is measured by a laser diffraction scattering method.
• An example of a device suitable for this measurement is the Microtrac MT3000 laser diffraction/scattering particle size distribution measuring device manufactured by Nikkiso Co., Ltd.
• the powder is poured into the cell of this device together with pure water, and the particle diameter is detected based on the light scattering information of the particles.
• Examples of the metal powder of the present invention include Ni-based alloy powder, Co-based alloy powder, Fe-based alloy powder, Cu-based alloy powder, etc.
• the metal powder of the present invention is a Ni-based alloy powder.
• the Ni-based alloy powder may be composed of Ni and inevitable impurities, or may contain one or more elements selected from Fe, Cr, C, Mn, Si, Mo, Co, Nb, Al, Ti and B in addition to Ni and inevitable impurities.
• the Ni-based alloy powder contains one or more elements selected from Fe, Cr, C, Mn, Si, Mo, Co, Nb, Al, Ti and B
• the balance of the Ni-based alloy powder is composed of Ni and inevitable impurities.
• the metal powder of the present invention is a Co-based alloy powder.
• the Co-based alloy powder may be composed of Co and inevitable impurities, or may contain one or two elements selected from Cr and Mo in addition to Co and inevitable impurities.
• the Co-based alloy powder contains one or two elements selected from Cr and Mo, the balance of the Co-based alloy powder is composed of Co and inevitable impurities.
• the metal powder of the present invention is an Fe-based alloy powder.
• the Fe-based alloy powder may be composed of Fe and inevitable impurities, or may contain, in addition to Fe and inevitable impurities, one or more elements selected from Ni, Co, Mo, Ti, Al, Cr, Cu and C.
• the Fe-based alloy powder contains one or more elements selected from Ni, Co, Mo, Ti, Al, Cr, Cu and C
• the balance of the Fe-based alloy powder is composed of Fe and inevitable impurities.
• the metal powder of the present invention is a Cu-based alloy powder.
• the Cu-based alloy powder may be composed of Cu and unavoidable impurities, or may contain Zr in addition to Cu and unavoidable impurities.
• the Cu-based alloy powder contains Zr, the balance of the Cu-based alloy powder is composed of Cu and unavoidable impurities.
• the metal powder of the present invention can be obtained by preparing a metal powder raw material having a predetermined component composition and classifying the prepared metal powder raw material.
• metal powder raw materials include Ni-based alloy powder, Co-based alloy powder, Fe-based alloy powder, and Cu-based alloy powder.
• Ni-based alloy powder, Co-based alloy powder, Fe-based alloy powder, and Cu-based alloy powder are the same as those described above.
• the atomization method is preferred.
• the gas atomization method is particularly preferred.
• the raw material is placed in a container (quartz crucible) with a small hole at the bottom, and the raw material is melted by high-frequency induction heating in an argon gas or nitrogen gas atmosphere.
• argon gas or nitrogen gas is sprayed, scattering the molten metal, which is then rapidly cooled and solidified to obtain the metal powder raw material.
• the metal powder raw material is a gas atomized powder produced by a gas atomization method.
• the classification of the metal powder raw material can be carried out, for example, by a dry vibrating sieve device.
• the vibrating sieve device is a device that efficiently sifts the metal powder raw material on the screen by vibrating the screen with a motor, vibrator, etc., and selects particles of a certain size from the metal powder raw material. To prevent clogging, tapping balls are usually bounced on the screen. The tapping balls are made of urethane, for example.
• a vibrating sieve device for example, a DALTON Vibrating Sieve (Inner Ring Type) 502 can be used.
• sieving is performed to adjust the particle size, and then sieving is performed to remove acicular particles.
• Sieving to adjust the particle size may also be performed after sieving to remove acicular particles.
• the metal powder raw material is sieved using a vibrating sieve device with a sieve with large openings while using tapping balls as usual, to obtain the undersize fraction.
• the undersize fraction obtained above is sieved using a vibrating sieve device with a sieve with small openings while using tapping balls as usual, to obtain the surplus fraction.
• the surplus fraction obtained is metal powder of the specified particle size (small to large openings).
• a vibrating sieving device using a sieve with large or larger openings is used without using tapping balls or with a reduced number of tapping balls to sieve the metal powder obtained by sieving to adjust particle size, actively removing the acicular particles and obtaining the undersieve.
• the obtained undersieve is the metal powder of the present invention in which the proportion of acicular particles is reduced.
• a sieve with a larger mesh size than the sieve used in sieving it is preferable to use a sieve with a larger mesh size than the sieve used in sieving to adjust the particle size in order to remove acicular particles. This is to prevent particles other than acicular particles from clogging and to increase the classification efficiency.
• a sieve with a nominal mesh size of 150 ⁇ m can be used.
• the particle size of the metal powder of the present invention is adjusted to 45 to 125 ⁇ m for deposition-based additive manufacturing by classification of the metal powder raw material.
• Metal powder with a particle size of 45 to 125 ⁇ m can be obtained by sieving the metal powder raw material using a sieve with a nominal mesh size of 125 ⁇ m, and then sieving the resulting undersize using a sieve with a nominal mesh size of 45 ⁇ m, to obtain the oversize.
• the classification procedure for obtaining metal powder having a particle size of 45 to 125 ⁇ m with a reduced proportion of acicular particles will be described below.
• the metal powder raw material is sieved using a vibrating sieve device using a sieve with a nominal opening of 125 ⁇ m to obtain an undersize fraction.
• the undersize fraction obtained above is sieved using a vibrating sieve device using a sieve with a nominal opening of 45 ⁇ m to obtain an oversize fraction.
• the oversize fraction obtained above is sieved using a vibrating sieve device using a sieve with a nominal opening of 150 ⁇ m to actively remove acicular powder to obtain an undersize fraction.
• the obtained undersize fraction is a metal powder with a particle size of 45 to 125 ⁇ m in which the number ratio of acicular particles is reduced.
• the additive manufacturing object of the present invention is an additive manufacturing object obtained by additive manufacturing using an additive manufacturing material that contains the metal powder of the present invention.
• Typical additive manufacturing methods include the powder bed method (powder bed fusion method) and the deposition method (directed energy deposition method).
• the additive manufacturing material may contain materials other than the metal powder of the present invention (e.g., a powder binder such as a resin powder), but it is preferable that it is composed only of the metal powder of the present invention.
• a powder binder such as a resin powder
• the additive manufacturing material containing the metal powder of the present invention is suitable for additive manufacturing using the deposition method.
• the porosity of the layered object of the present invention is preferably 0.14% or less, more preferably 0.12% or less, and even more preferably 0.06% or less.
• the lower limit of the porosity of the layered object of the present invention is preferably as small as possible.
• the relative density can be measured as follows.
• the density (g/mm 3 ) of the layered object is calculated using the weight of the layered object in air, the weight in water, and the density of water (Archimedes density measurement method).
• the density (g/mm 3 ) of the powder used in manufacturing the layered object is calculated by dry density measurement using a constant volume expansion method (gas used: helium gas, device used: Shimadzu micromeritics AccuPyc1330).
• the relative density ( % ) of the layered object is calculated from the density of the layered object and the density of the powder based on the following formula.
• Relative density (%) of layered product density of layered product / density of powder x 100
• the metal powder of the present invention has a small proportion of acicular particles and has little effect on the deterioration of fluidity, so additive manufacturing using the metal powder of the present invention makes it possible to obtain a dense additive manufacturing body with a low porosity.
• a metal powder raw material having the following composition was prepared by gas atomization. The percentages in the following composition are by mass.
• Ni-based alloy powder Fe: 23%, Cr: 20%, C: 0.05%, Mn: 0.1%, Si: 0.2%, Mo: 3.0%, Co: 0.3 %, Nb: 5.2%, Al: 0.5%, Ti: 0.9%, B: 0.003%, remainder: Ni and inevitable impurities
• Fe-based alloy powder Ni: 18.0%, Co: 9.0%, Mo: 4.9%, Ti: 0.7%, Al: 0.1%, Cr: 0.2%, Cu: 0.1%, C: 0.02%, balance: Fe and unavoidable impurities (this powder is made of maraging steel)
• Ni-based alloy powder was used in Examples 1 and 2, Co-based alloy powder in Examples 3 and 4, Fe-based alloy powder in Examples 5 and 6, and Cu-based alloy powder in Examples 7 and 8.
• Ni-based alloy powder was used in Comparative Examples 1 to 3, Co-based alloy powder in Comparative Examples 4 to 6, Fe-based alloy powder in Comparative Examples 7 to 9, and Cu-based alloy powder in Comparative Examples 10 to 12.
• the metal powder raw material was classified. Classification was performed using a dry vibrating sieve device (Dalton's vibrating sieve (inner ring type) 502). By classifying the metal powder raw material, a metal powder with a particle size of 45 to 125 ⁇ m in which the number ratio of acicular particles was reduced was obtained as metal powder for deposition-type additive manufacturing.
• the specific classification procedure is as follows.
• the metal powder raw material was sieved using a vibrating sieve device with a sieve with a nominal mesh size of 125 ⁇ m while using tapping balls as usual, to obtain the undersize.
• the undersize obtained above was sieved using a vibrating sieve device with a sieve with a nominal mesh size of 45 ⁇ m while using tapping balls as usual, to obtain the surplus.
• the surplus was sieved using a vibrating sieve device with a sieve with a nominal mesh size of 150 ⁇ m to actively remove acicular particles, to obtain the undersize.
• the undersize obtained is metal powder with a particle size of 45 to 125 ⁇ m with a reduced proportion of acicular particles.
• the median diameter D50 was measured by a laser diffraction scattering method using a laser diffraction/scattering type particle size distribution measuring device "Microtrac MT3000" manufactured by Nikkiso Co., Ltd.
• the flowability of the metal powder was evaluated based on JIS Z2502:2020. Specifically, the orifice at the bottom of a funnel containing 50 g of a metal powder sample was opened, and the flowability was evaluated by measuring the time (s/50 g) required for 50 g of powder to fall from the funnel. The ease of handling of the powder under normal conditions while the nozzle is not blocked can be evaluated using this flowability as a guide.
• Metal powder with a particle size of 45 to 125 ⁇ m and a reduced proportion of acicular particles was used to fabricate blocks with a square of 10 mm using a deposition-type three-dimensional additive manufacturing device (Mitsubishi Heavy Industries Machine Tool Co., Ltd., LAMDA200).
• the relative density was measured as follows.
• the density (g/mm 3 ) of the layered object was calculated using the weight of the layered object in air, the weight in water, and the density of water (Archimedes density measurement method).
• the density (g/mm 3 ) of the powder used in the manufacture of the layered object was calculated by dry density measurement using a constant volume expansion method (gas used: helium gas, device used: Shimadzu micromeritics AccuPyc1330).
• the relative density ( % ) of the layered object was calculated from the density of the layered object and the density of the powder based on the following formula.
• Relative density (%) of layered product density of layered product / density of powder x 100
• the metal powders of Examples 1 to 8 had a low percentage of acicular particles and little effect on the deterioration of fluidity, so when additive manufacturing was performed, the additive manufactured body had a low porosity and was dense.
• the metal powders of Comparative Examples 1 to 12 had a high proportion of acicular particles, and therefore the porosity of the additively manufactured body was higher than that of the metal powders of Examples 1 to 8.
• the metal powders of Comparative Examples 3, 6, 9, and 12 contained particles with a maximum major axis exceeding 1000 ⁇ m, which led to blockages during additive manufacturing, making it impossible to obtain an additively manufactured body.
• the metal powder of the present invention is suitable as a metal powder for additive manufacturing, which is used for three-dimensional additive manufacturing of metal parts, etc., and is particularly suitable as a metal powder for additive manufacturing using the deposition method.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Nanotechnology (AREA)
• Powder Metallurgy (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=92675058

Family Applications (1)

Country Status (4)

Citations (6)

Family Cites Families (1)

• 2023
  • 2023-03-03 JP JP2023033116A patent/JP7615195B2/ja active Active
• 2024
  • 2024-03-01 EP EP24767066.4A patent/EP4678309A1/en active Pending
  • 2024-03-01 WO PCT/JP2024/007810 patent/WO2024185698A1/ja not_active Ceased
  • 2024-03-01 CN CN202480015476.4A patent/CN120769786A/zh active Pending
  • 2024-12-26 JP JP2024231340A patent/JP7813865B2/ja active Active

Patent Citations (6)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events