Powder for laminate molding, and laminate molded body

Abstract

Provided are: a powder for laminate molding, which has both good sinterability and flowability and good permeability of an aqueous binder solution; and a laminate molded body comprising the powder for laminate molding. A powder for laminate molding, which contains an Fe-based metal material, is used in a binder injection method, and is characterized by having a particle diameter D50 of 1.0 [mu] m or more and less than 15.0 [mu] m, a particle diameter difference D90-D10 between the particle diameter D90 and the particle diameter D10 of 5.0 [mu] m or more and 18.0 [mu] m or less, a specific surface area of 0.05 [m2 / g] or more and 0.25 [m2 / g] or less, and an average circularity of 0.85 or more and 0.99 or less, when a plurality of droplets of an aqueous PVP solution for evaluation are dropped at the same position at a total of 1.36 mL to an evaluation powder layer formed by powder pressing with a relative density of 45% to 47% and a thickness of 10 mm, the depth of penetration of the aqueous PVP solution for evaluation is 110 [mu] m to 250 [mu] m.

Description

Technical Field

[0001] The present invention relates to powder for laminated molding and a laminated molding body. Background Art

[0002] In recent years, laminated modeling methods using metal powders have become increasingly popular as a technology for creating three-dimensional objects. Known laminated modeling methods, based on the principle of bonding, include fused deposition modeling (FDM), selective laser sintering (SLS), and binder jetting.

[0003] Patent document 1 discloses a metal powder for molding, which is composed of a plurality of particles, wherein the particles contain at least one of Ni, Fe, and Co, and the total content of Ni, Fe, and Co is 50% by mass or more, wherein the ratio P1 of the number of particles having a roundness of less than 0.80 to the total number of particles is 10% or less, and the ratio P3 of the number of particles having a roundness of 0.95 or more to the total number of particles is 50% or more.

[0004] According to such a metal powder for modeling, since it contains many particles with large roundness, it is excellent in handleability and can produce a high-strength modeled object.

[0005] Furthermore, a metal sintered body can be efficiently produced by sintering the produced shaped body.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-102229

[0007] However, the metal powder for molding described in Patent Document 1 has a relatively large particle size D50, equivalent to an average particle size of 15 μm or more. Consequently, the resulting molded object suffers from poor sinterability of the metal powder. Furthermore, as the particle size decreases, the powder's fluidity decreases, and there is a tendency for the powder's packing capacity to decline. Therefore, when reducing the particle size to improve sinterability, it is necessary to increase the powder's fluidity. Furthermore, as the particle size decreases, the powder's surface area increases. Consequently, depending on the surface state of the particles that make up the powder, the permeability of the aqueous binder solution may decrease. If the permeability decreases, the shape accuracy of the molded object decreases.

[0008] Therefore, it is a challenge to realize a powder for laminated molding that has both good sinterability and fluidity and good permeability to aqueous binder solutions. Summary of the Invention

[0009] The laminated molding powder according to the application example of the present invention contains an Fe-based metal material and is used in a binder jetting method.

[0010] In a volume-based cumulative particle size distribution curve measured by a laser diffraction method, where the particle size at which the cumulative value from the small diameter side is 10% is defined as D10, the particle size at which the cumulative value from the small diameter side is 50% is defined as D50, and the particle size at which the cumulative value from the small diameter side is 90% is defined as D90, the particle size D50 is 1.0 μm or more and less than 15.0 μm, and the particle size difference D90-D10 between the particle size D90 and the particle size D10 is 5.0 μm or more and 18.0 μm or less,

[0011] The specific surface area is 0.05[m 2 / g] and above 0.25[m 2 / g] or below,

[0012] The average roundness is 0.85 or more and 0.99 or less.

[0013] When multiple droplets of the evaluation PVP aqueous solution totaling 1.36 mL are dropped at the same position onto the evaluation powder layer formed by compacting the powder to a relative density of 45% to 47% and a thickness of 10 mm, the penetration depth of the above-mentioned evaluation PVP aqueous solution is 110 μm to 250 μm.

[0014] The stacked structure according to the application example of the present invention has:

[0015] Powder for laminated molding according to an application example of the present invention; and

[0016] A binder that binds the particles of the laminated modeling powder to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a process diagram for explaining a method for manufacturing a stacked structure.

[0018] Figure 2 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0019] Figure 3 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0020] Figure 4 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0021] Figure 5 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0022] Figure 6 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0023] Figure 7 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0024] Figure 8 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0025] Figure 9 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0026] Figure 10 It is used for Figure 1 The diagram illustrates a method for manufacturing a stacked structure shown in FIG.

[0027] Figure 11 This is a cross-sectional view for explaining a method for measuring the penetration depth of the evaluation PVP aqueous solution into the evaluation powder layer.

[0028] Description of Reference Signs

[0029] 1: Powder for stacking molding; 2: Stacking molding device; 4: Adhesive solution; 6: Stacking molding body; 10: Powder layer for evaluation; 20: Container; 21: Device body; 22: Powder supply elevator; 23: Molding workbench; 24: Coating machine; 25: Roller; 26: Liquid supply unit; 30: Inkjet head; 31: Powder layer; 40: PVP aqueous solution for evaluation; 41: Adhesive layer; 60: Forming area; 211: Powder storage unit; 212: Molding unit; S102: Powder layer forming process; S104: Adhesive solution supply process; S106: Repeating process; d: Penetration depth. DETAILED DESCRIPTION

[0030] Hereinafter, the laminated molding powder and the laminated molding body of the present invention will be described in detail based on the embodiments shown in the drawings.

[0031] 1. Method for manufacturing a laminated body

[0032] First, a method for producing a laminated molding body using the laminated molding powder will be described.

[0033] Figure 1 This is a process diagram for explaining a method for manufacturing a stacked structure. Figures 2 to 10 They are used for Figure 1 The method for manufacturing the stacked molding shown in FIG. Figures 2 to 10In the , the X-axis, Y-axis, and Z-axis are defined as three mutually orthogonal axes. Each axis is represented by an arrow, with the distal end side being the "positive side" and the proximal end side being the "negative side." In the following description, the positive side of the Z-axis is specifically referred to as "up" and the negative side of the Z-axis is referred to as "down." Furthermore, the two directions parallel to the X-axis are referred to as X-axis directions, the two directions parallel to the Y-axis are referred to as Y-axis directions, and the two directions parallel to the Z-axis are referred to as Z-axis directions.

[0034] Figures 1 to 10 The method for manufacturing the stacked molding body shown is a method called a binder jet method as a type of stacking molding method. Figure 1 As shown, the process includes a powder layer forming step S102, a binder solution supplying step S104, and a repetition step S106. The binder spraying method has the advantage of being able to produce a complex-shaped laminated body because it does not require a support structure for the body.

[0035] In the powder layer forming step S102, the modeling powder 1 is laid to form a powder layer 31. In the binder solution supplying step S104, the binder solution 4 is supplied to a predetermined area of ​​the powder layer 31 to bind the particles in the powder layer 31 to form a bonding layer 41. In the repetition step S106, the powder layer forming step S102 and the binder solution supplying step S104 are repeated one or more times to form a bonding layer 41. Figure 10 The stacked shaped body 6 shown in FIG.

[0036] The produced stacked shaped body 6 is subjected to a sintering process to become a metal sintered body. This allows efficient production of a metal sintered body having a complex shape.

[0037] 1.1.Layered modeling device

[0038] First, the stacked molding apparatus 2 used for manufacturing the stacked molding body 6 will be described.

[0039] like Figures 2 to 10 As shown, the stacking molding device 2 includes: a device body 21, which has a powder storage part 211 and a molding part 212; a powder supply elevator 22, which is arranged in the powder storage part 211; a molding workbench 23, which is arranged in the molding part 212; and a coater 24, a roller 25 and a liquid supply part 26 movably arranged on the device body 21.

[0040] The powder storage section 211 is a recessed portion with an opening at the top provided in the apparatus body 21. The powder storage section 211 stores the laminated molding powder 1. An appropriate amount of the laminated molding powder 1 stored in the powder storage section 211 is supplied to the molding section 212 via the coater 24.

[0041] A powder supply elevator 22 is located at the bottom of the powder storage section 211. The powder supply elevator 22 is movable vertically while holding the layered molding powder 1. By moving the powder supply elevator 22 upward, the layered molding powder 1 held on the powder supply elevator 22 is pushed upward, causing it to overflow from the powder storage section 211. This allows the overflowed layered molding powder 1 to be moved toward the molding section 212.

[0042] The molding section 212 is a recessed portion with an upper opening provided in the apparatus main body 21. A molding table 23 is disposed within the molding section 212. The coating machine 24 applies the layered molding powder 1 to the molding table 23 in a layered manner. The molding table 23 is movable vertically while the layered molding powder 1 is applied. The amount of the layered molding powder 1 applied to the molding table 23 can be adjusted by appropriately setting the height of the molding table 23.

[0043] like Figure 3 and Figure 4 As shown, the coater 24 and roller 25 can move in the X-axis direction from the powder storage section 211 to the molding section 212. The coater 24 can flatten the laminated molding powder 1 by dragging it, and lay it in a layer. The roller 25 compresses the flattened laminated molding powder 1 from above.

[0044] The liquid supply unit 26 is composed of, for example, an inkjet head or a dispenser, and is movable in the X-axis and Y-axis directions within the molding unit 212. Furthermore, the liquid supply unit 26 is capable of supplying a target amount of the binder solution 4 to a target location. Furthermore, the liquid supply unit 26 may include multiple discharge nozzles on a single head. Furthermore, the binder solution 4 may be discharged from the multiple discharge nozzles simultaneously or with a time difference.

[0045] 1.2. Powder layer formation process

[0046] Next, the powder layer forming step S102 using the stacking molding apparatus 2 will be described. In the powder layer forming step S102, the stacking molding powder 1 is laid on the molding table 23 to form a powder layer 31. Specifically, Figure 2 and Figure 3 As shown, the coating machine 24 is used to drag the layered molding powder 1 stored in the powder storage portion 211 onto the molding workbench 23 and level it to a uniform thickness. Figure 4The powder layer 31 shown is shown. At this time, the thickness of the powder layer 31 can be adjusted by lowering the upper surface of the molding table 23 relative to the upper end of the molding section 212 and adjusting the amount of lowering. Furthermore, as will be described later, the laminated molding powder 1 has excellent filling properties when flattened. Therefore, a powder layer 31 with a high filling rate can be obtained.

[0047] Next, the powder layer 31 is compressed in the thickness direction by the roller 25, and as shown in FIG. Figure 4 As shown, the roller 25 is moved in the X-axis direction. This can increase the filling rate of the layered modeling powder 1 in the powder layer 31. Furthermore, compression by the roller 25 can be performed as needed or omitted. Alternatively, the powder layer 31 can be compressed by a means other than the roller 25, such as a pressing plate.

[0048] 1.3. Binder solution supply process

[0049] In the binder solution supplying step S104, Figure 5 As shown, the binder solution 4 is supplied to the forming area 60 corresponding to the stacked molding body 6 to be molded in the powder layer 31 by the liquid supply unit 26. The binder solution 4 is a liquid containing a binder and water (aqueous binder solution). In the forming area 60 supplied with the binder solution 4, the particles of the stacked molding powder 1 are bonded to each other to obtain Figure 6 The bonding layer 41 is shown. In the bonding layer 41, particles of the laminated modeling powder 1 are bonded to each other by a binder, and have a shape retention property to such an extent that they are not damaged by their own weight.

[0050] Alternatively, the adhesive layer 41 may be heated simultaneously with or after the supply of the adhesive solution 4. This promotes the volatilization of the solvent and dispersion medium contained in the adhesive solution 4 and promotes the bonding of the particles due to the curing or hardening of the adhesive. Furthermore, if the adhesive comprises a photocurable resin or an ultraviolet curable resin, light irradiation or ultraviolet irradiation may be performed instead of or in addition to heating.

[0051] The heating temperature is not particularly limited, but is preferably 50° C. to 250° C., more preferably 70° C. to 200° C. This allows sufficient heat to be applied to the adhesive layer 41, thereby sufficiently promoting volatilization of the solvent and dispersion medium.

[0052] The binder solution 4 may also contain other solvents along with water. Examples of the solvent include alcohols, ketones, and carboxylates, and at least one of these is used. Furthermore, examples of the binder contained in the binder solution 4 include fatty acids, paraffin wax, microwax, polyethylene, polypropylene, polystyrene, acrylic resins, polyamide resins, polyesters, stearic acid, polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyurethane resins, epoxy resins, vinyl resins, unsaturated polyester resins, and phenolic resins.

[0053] 1.4. Repeating process

[0054] In the repetition step S106, the powder layer forming step S102 and the binder solution supplying step S104 are repeated one or more times until the laminated body formed by laminating a plurality of adhesive layers 41 has a predetermined shape. That is, these steps are performed two or more times in total. Figure 10 The three-dimensional stacked structure 6 is shown.

[0055] Specifically, first, Figure 7 As shown, in Figure 6 The bonding layer 41 shown forms a new powder layer 31. Next, as Figure 8 As shown, the binder solution 4 is supplied to the formation region 60 in the newly formed powder layer 31. Figure 9 By repeating these operations, the second adhesive layer 41 is obtained. Figure 10 The stacked shaped body 6 is shown.

[0056] Furthermore, the laminated molding powder 1 that does not constitute the bonding layer 41 in the powder layer 31 is recovered and reused as needed, that is, supplied again to the production of the laminated molding body 6 .

[0057] The stacked shaped body 6 obtained as described above is subjected to a sintering process described later.

[0058] 1.5. Method for manufacturing a sintered metal body

[0059] A metal sintered body is obtained by sintering the stacked shaped body 6. In the sintering process, the stacked shaped body 6 is heated to cause a sintering reaction.

[0060] The sintering temperature varies depending on the constituent materials and particle size of the laminated modeling powder 1, but is preferably, for example, 980°C to 1330°C, more preferably 1050°C to 1260°C. The sintering time is preferably 0.2 hours to 7 hours, more preferably 1 hour to 6 hours.

[0061] Examples of the sintering environment include a reducing atmosphere such as hydrogen, an inert atmosphere such as nitrogen or argon, or a reduced pressure atmosphere obtained by reducing the pressure of these atmospheres. The reduced pressure atmosphere is not particularly limited as long as the pressure is less than normal pressure (100 kPa), but is preferably 10 kPa or less, and more preferably 1 kPa or less.

[0062] Furthermore, when the sintering process performed under the above-described conditions is defined as "main sintering," the stacked shaped body 6 may, if necessary, undergo "temporary sintering" or "debinding," which is equivalent to pre-treatment before the main sintering. This can remove at least a portion of the binder contained in the stacked shaped body 6 or cause a sintering reaction to occur in a portion. This can prevent unintended deformation during the main sintering process.

[0063] The temperature for sintering and degreasing is not particularly limited, as long as it is a temperature that does not completely sinter the metal powder, but is preferably 100°C to 500°C, more preferably 150°C to 300°C. Furthermore, the time for sintering and degreasing is preferably 5 minutes or longer, more preferably 10 minutes to 120 minutes, and even more preferably 20 minutes to 60 minutes, within the above-mentioned temperature range. Examples of the sintering and degreasing environment include atmospheric air, an inert atmosphere such as nitrogen or argon, or a reduced pressure environment obtained by reducing the pressure of these atmospheres.

[0064] The metal sintered body obtained as described above can be used as a material for, for example, automobile parts, bicycle parts, railway vehicle parts, ship parts, aircraft parts, and transportation equipment parts such as space transport parts, electronic equipment parts such as personal computer parts, mobile phone terminal parts, tablet terminal parts, and wearable terminal parts, electrical equipment parts such as refrigerators, washing machines, and air conditioners, mechanical parts such as machine tools and semiconductor manufacturing equipment, factory parts such as nuclear power plants, thermal power plants, hydroelectric power plants, refineries, and chemical complexes, watch parts, metal tableware, jewelry, and decorative items such as eyeglass frames.

[0065] 2. Layering powder

[0066] Next, the powder for laminated modeling according to the embodiment will be described.

[0067] The laminated modeling powder 1 according to this embodiment is a powder used in a binder jetting method.

[0068] 2.1. Constituent materials

[0069] The laminated molding powder 1 contains an Fe-based metal material. The Fe-based metal material is a metal material having an Fe content exceeding 50% by atomic ratio.

[0070] Examples of Fe-based metal materials include stainless steels such as austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, precipitation-hardening stainless steel, and austenitic-ferritic (duplex) stainless steel, low-carbon steel, carbon steel, heat-resistant steel, die steel, high-speed tool steel, Fe-Ni alloys, and Fe-Ni-Co alloys.

[0071] Among these, stainless steel is preferably used as the Fe-based metal material. Stainless steel is a type of steel with excellent mechanical strength and corrosion resistance. Therefore, by using the laminated molding powder 1 composed of stainless steel, a metal sintered body with excellent mechanical strength and corrosion resistance and high shape accuracy can be efficiently produced.

[0072] Among stainless steels, precipitation-hardening stainless steel is particularly preferably used. Precipitation-hardening stainless steel has excellent mechanical strength and toughness due to the formation of precipitates.

[0073] Examples of austenitic stainless steel include SUS301, SUS301L, SUS301J1, SUS302B, SUS303, SUS304, SUS304Cu, SUS304L, SUS304N1, SUS304N2, SUS304LN, SUS304J1, SUS304J2, SUS305, SUS309S, SUS310S, SUS312L, and SUS315 J1, SUS315J2, SUS316, SUS316L, SUS316N, SUS316LN, SUS316Ti, SUS316J1, SUS316J1L, SUS317, SUS317L, SUS317LN, SUS317J1, SUS317J2, SUS836L, SUS890L, SUS321, SUS347, SUSXM7, SUSXM15J1, etc.

[0074] Examples of ferritic stainless steel include SUS405, SUS410L, SUS429, SUS430, SUS430LX, SUS430J1L, SUS434, SUS436L, SUS436J1L, SUS445J1, SUS445J2, SUS444, SUS447J1, and SUS XM27.

[0075] Examples of martensitic stainless steel include SUS403, SUS410, SUS410S, SUS420J1, SUS420J2, and SUS440A.

[0076] Examples of precipitation-hardening stainless steel include SUS630 (17-4PH) and SUS631 (17-7PH).

[0077] Examples of austenite-ferrite (two-phase) stainless steel include SUS329J1, SUS329J3L, and SUS329J4L.

[0078] The above symbols are material symbols based on the JIS standard. The types of stainless steel in this specification are distinguished by the above material symbols.

[0079] Furthermore, the laminated modeling powder 1 may be provided with a coating covering the surface of the core particles composed of an Fe-based metal material. This coating is provided, for example, to improve the flowability and filling properties of the laminated modeling powder 1 or to enhance the compatibility between the laminated modeling powder 1 and the binder. Examples of materials constituting the coating include organic materials such as resins, inorganic materials such as ceramics and glass, and compounds derived from coupling agents.

[0080] 2.2. Various properties of powders for laminated modeling

[0081] Next, various properties of the powder for laminated modeling 1 will be described. Note that the following properties are all properties measured in a state where the powder for laminated modeling 1 is not provided with the above-mentioned coating.

[0082] 2.2.1. Evaluation of the penetration depth of PVP aqueous solution

[0083] When the evaluation powder layer 10 is formed using the laminated modeling powder 1 according to this embodiment, the evaluation powder layer 10 has the characteristic that the penetration depth of the evaluation PVP aqueous solution 40 is within a predetermined range. The penetration depth of the evaluation PVP aqueous solution 40 in the evaluation powder layer 10 serves as an indicator that quantitatively represents the permeability of the binder solution 4 in the aforementioned binder jetting method. By optimizing this indicator, a laminated modeling powder 1 can be produced that can form a powder layer 31 with excellent permeability of the binder solution 4, even when the particle size of the laminated modeling powder 1 is small.

[0084] The evaluation PVP aqueous solution 40 is used to quantitatively measure the permeability of the binder solution 4 used in the binder spraying method. This evaluation PVP aqueous solution 40 is an aqueous solution containing PVP and 2-butoxyethanol. The PVP (polyvinyl pyrrolidone) content in the evaluation PVP aqueous solution 40 is 8% by mass, the 2-butoxyethanol content is 2% by mass, and the remainder is ion-exchanged water. The viscosity of the evaluation PVP aqueous solution 40 is set to 0.006 [Pa·s] (6 cP).

[0085] The penetration depth d of the evaluation PVP aqueous solution 40 is measured as follows.

[0086] Figure 11 This is a cross-sectional view for explaining a method of measuring the penetration depth of the evaluation PVP aqueous solution 40 into the evaluation powder layer 10 .

[0087] To measure the penetration depth d of the evaluation PVP aqueous solution 40, first, the layered modeling powder 1 is placed in a container 20 and compacted to form an evaluation powder layer 10. The evaluation powder layer 10 has a thickness of 10 mm and a relative density of 45% to 47%. The horizontal size of the evaluation powder layer 10 is set to account for the diffusion of the evaluation PVP aqueous solution 40, for example, to a size of 30 mm square or greater. The relative density is calculated by dividing the mass of the evaluation powder layer 10 by its volume to obtain a density, and then dividing this density by the true density of the layered modeling powder 1.

[0088] Next, multiple droplets of the PVP aqueous solution 40 for evaluation were ejected from the inkjet head 30 toward one location on the evaluation powder layer 10. The resolution of the inkjet head 30 used was 600 dpi, the droplet ejection rate was 7.17 m / s, the total amount of the PVP aqueous solution 40 for evaluation ejected toward one location was 1.36 mL, and the air temperature was 23°C.

[0089] Next, the powder layer 10 for evaluation was heated at 100° C. for 1 hour. This removed the water in the ejected PVP aqueous solution 40 for evaluation, and solidified the area where the PVP aqueous solution 40 for evaluation had penetrated.

[0090] Next, the solidified portion is removed from the evaluation powder layer 10. The length from the surface of the evaluation powder layer 10 to the deepest part (the length of the solidified portion) is measured. The measurement result is used as the penetration depth of the evaluation PVP aqueous solution 40 (penetration depth d).

[0091] In the evaluation powder layer 10 using the laminated molding powder 1 according to this embodiment, the penetration depth d of the evaluation PVP aqueous solution 40 is 110 μm or more and 250 μm or less. With a laminated molding powder 1 having a penetration depth within this range, even when the laminated molding powder 1 has a small particle size and a high particle surface energy, a powder layer 31 can be formed that is sufficiently permeable to the aqueous binder solution 4. Therefore, when used to manufacture laminated molding bodies 6 using a binder jetting method, a laminated molding powder 1 capable of producing laminated molding bodies 6 with high shape accuracy can be achieved.

[0092] Furthermore, the above-mentioned penetration depth d is preferably 130 μm or more and 220 μm or less, and more preferably 150 μm or more and 200 μm or less.

[0093] Furthermore, if the penetration depth d is below the lower limit, the binder solution 4 cannot penetrate into the target range in the binder solution supply step S104, resulting in reduced shape accuracy of the stacked molded body 6. Furthermore, since penetration takes time, the molding speed of the stacked molded body 6 decreases. On the other hand, if the penetration depth d is above the upper limit, the binder solution 4 penetrates too far in the binder solution supply step S104, causing so-called oozing, which reduces the shape accuracy of the stacked molded body 6.

[0094] Furthermore, preferably, all the droplets of the discharged PVP aqueous solution 40 for evaluation penetrate into the powder layer 10 for evaluation within 3 seconds, more preferably within 1 second, starting from the time of the last droplet discharge.

[0095] Particle size distribution

[0096] Regarding the powder for laminated molding 1 according to this embodiment, when the volume-based particle size distribution is obtained using a laser diffraction particle size distribution analyzer, the particle size at which the cumulative frequency from the small diameter side reaches 10% is designated as D10. Similarly, the particle sizes at which the cumulative frequency from the small diameter side reaches 50%, 90%, and 99% are designated as D50, D90, and D99, respectively. Examples of particle size distribution measuring instruments include the Nikkiso Co., Ltd. Microtrac and HRA9320-X100.

[0097] The particle size D50 of the laminated molding powder 1 is 1.0 μm or greater and less than 15.0 μm, preferably 3.0 μm or greater and 12.0 μm or less, and more preferably 4.0 μm or greater and 10.0 μm or less. This allows for a balance between sinterability and flowability of the laminated molding powder 1. As a result, a dense laminated molding body 6 with high molding accuracy can be obtained. This laminated molding body 6 can ultimately be used to manufacture a high-density, high-surface-accuracy metal sintered body.

[0098] If the particle size D50 is below the lower limit, the particles of the layered modeling powder 1 tend to aggregate. This reduces the fluidity of the layered modeling powder 1 and reduces the density of the metal sintered body. On the other hand, if the particle size D50 is above the upper limit, the sinterability of the layered modeling powder 1 decreases, reducing the density of the metal sintered body.

[0099] The ratio D10 / D50 of the particle size D10 to the particle size D50 is preferably 0.30 or more and 0.70 or less, more preferably 0.35 or more and 0.60 or less, and even more preferably 0.42 or more and 0.55 or less. As a result, the particle size of the powder 1 for stacking modeling becomes relatively consistent, which makes it easy to improve fluidity and ensure sinterability. In addition, if the ratio D10 / D50 is lower than the above lower limit, the particle size distribution becomes wider, and there is a concern that fluidity is reduced. On the other hand, when the ratio D10 / D50 is higher than the above upper limit, the particle size distribution is too narrow, making it difficult to increase the filling rate, and there is a concern that sinterability is reduced.

[0100] The ratio D90 / D50 of the particle size D90 to the particle size D50 is preferably 1.50 or more and 2.70 or less, more preferably 1.70 or more and 2.60 or less, and even more preferably 1.90 or more and 2.50 or less. As a result, the particle size of the powder 1 for stacking modeling becomes relatively consistent, which makes it easy to improve fluidity and ensure sinterability. In addition, if the ratio D90 / D50 is lower than the above lower limit, the particle size distribution becomes narrower, making it difficult to increase the filling rate, and there is a concern that sinterability will be reduced. On the other hand, if the ratio D90 / D50 is higher than the above upper limit, the particle size distribution becomes wider, and there is a concern that fluidity will be reduced.

[0101] The particle size difference D90-D10 between the particle size D90 and the particle size D10 is 5.0 μm or greater and 18.0 μm or less, preferably 8.0 μm or greater and 15.0 μm or less, and more preferably 9.0 μm or greater and 13.0 μm or less. This results in a sufficiently narrow particle size distribution of the laminated molding powder 1, achieving high flowability. Consequently, the packing properties of the laminated molding powder 1 are enhanced, enabling the production of a dense laminated molding body 6 with high molding accuracy.

[0102] Furthermore, if the particle size difference D90-D10 falls below the lower limit, the particle size distribution of the laminated modeling powder 1 becomes extremely narrow, making it difficult to increase the filling rate and reducing sinterability. Consequently, the density and surface accuracy of the resulting metal sintered body decrease. On the other hand, if the particle size difference D90-D10 exceeds the upper limit, the particle size distribution of the laminated modeling powder 1 becomes broad, reducing flowability. Consequently, the density and surface accuracy of the resulting sintered body decrease.

[0103] Specific surface area

[0104] The specific surface area of ​​the powder 1 for laminated molding is 0.05 [m 2 / g] and above 0.25[m 2 / g] or less, preferably 0.10 [m 2 / g] and above 0.22[m 2 / g] or less, more preferably 0.15 [m 2 / g] and above 0.20[m 2 / g] or less. When the specific surface area is within the above range, both the sinterability and flowability of the laminated molding powder 1 are achieved. Furthermore, since the surface energy is optimized, the penetration depth of the binder solution 4 is also optimized, allowing the binder solution 4 to quickly penetrate the target area. As a result, a dense laminated molding body 6 with high molding accuracy can be obtained, and this laminated molding body 6 can ultimately be used to produce a high-density, high-surface-accuracy metal sintered body.

[0105] Furthermore, if the specific surface area is below the lower limit, the sinterability of the laminated molding powder 1 decreases, reducing the density of the metal sintered body. Furthermore, the permeation distance of the binder solution 4 becomes excessively long, raising the concern that molding accuracy may be reduced. On the other hand, if the specific surface area exceeds the upper limit, while the sinterability of the laminated molding powder 1 is improved, the flowability of the laminated molding powder 1 decreases, reducing the density and surface accuracy of the metal sintered body. Furthermore, the permeation depth of the binder solution 4 becomes insufficient, raising the concern that the binder solution 4 may not penetrate the target area.

[0106] The specific surface area of ​​the laminated molding powder 1 is determined by the BET method. An example of a specific surface area measuring apparatus is the BET specific surface area measuring apparatus HM1201-010 manufactured by Mountech Co., Ltd. The sample amount is 5 g.

[0107] 2.2.4. Average roundness

[0108] The average roundness of the powder 1 for stacking modeling is greater than or equal to 0.85 and less than or equal to 0.99, preferably greater than or equal to 0.86 and less than or equal to 0.98, and more preferably greater than or equal to 0.87 and less than or equal to 0.97. Thus, even if the particle size of the powder 1 for stacking modeling is small, the particles are easy to roll, and the filling state can be made close to the densest filling. As a result, both the sintering property and the fluidity of the powder 1 for stacking modeling can be taken into account. In addition, since the surface energy is optimized, the penetration depth of the binder solution 4 is also optimized, and the binder solution 4 can be quickly penetrated into the target range. Thus, a dense and high-precision stacking modeling body 6 can be obtained, and the stacking modeling body 6 can ultimately be used to manufacture a high-density and high-surface-precision metal sintered body.

[0109] Furthermore, if the average circularity is below the lower limit, the average circularity decreases, thereby reducing the flowability of the laminated modeling powder 1 and the filling rate. Furthermore, the penetration depth of the binder solution 4 becomes insufficient, raising the concern that the binder solution 4 may not penetrate the target range. On the other hand, if the average circularity exceeds the upper limit, manufacturing becomes more difficult, reducing the efficiency of manufacturing the laminated modeling powder 1. Furthermore, the penetration distance of the binder solution 4 becomes excessively long, raising the concern that molding accuracy may be reduced.

[0110] The average circularity of the powder 1 for laminated molding is measured as follows.

[0111] First, an image (two-dimensional electron image) of the powder 1 for laminated molding is captured using a scanning electron microscope (SEM). Next, the obtained image is read into image processing software. The image processing software may be, for example, "Mac-View," an image analysis-type particle size distribution measurement software manufactured by Mountech Co., Ltd. In addition, the imaging magnification is adjusted so that 50 to 100 particles are captured in one image. Furthermore, multiple images are acquired to obtain a total of 300 or more particle images.

[0112] Next, the software is used to calculate the circularity of more than 300 particle images and the average value is calculated. The obtained average value becomes the average circularity of the laminated modeling powder 1. Furthermore, where the circularity is defined as e, the area of ​​the particle image is defined as S, and the perimeter of the particle image is defined as L, the circularity e is calculated using the following formula.

[0113] e=4πS / L 2

[0114] 2.2.5. Water content

[0115] The moisture content of the powder for laminated modeling 1 is preferably 200 ppm or less, more preferably 30 ppm or more and 200 ppm or less, even more preferably 40 ppm or more and 150 ppm or less, and particularly preferably 50 ppm or more and 100 ppm or less. When the moisture content is within this range, the decrease in fluidity associated with water adsorption is suppressed. Thus, a powder for laminated modeling 1 with excellent fluidity can be obtained. Furthermore, when the moisture content is within this range, the ease of charging of the powder for laminated modeling 1 can be controlled within an appropriate range, thus suppressing the decrease in fluidity associated with charging.

[0116] If the water content is below the lower limit, the powder for laminated modeling 1 may be easily charged, which may reduce the fluidity. On the other hand, if the water content is above the upper limit, the powder for laminated modeling 1 may have too much water, which may reduce the fluidity.

[0117] The moisture content of the laminated modeling powder 1 is measured by placing the laminated modeling powder 1 in an environment at a temperature of 25°C and a relative humidity of 50% for at least one hour and then measuring it at 250°C using the Karl Fischer method. The measurement is performed using, for example, a moisture analyzer CA-310 manufactured by Nitto Seiko Analytical Science Co., Ltd.

[0118] 2.2.6. Oxygen content

[0119] The oxygen content of the laminated modeling powder 1 is preferably 1000 ppm to 4000 ppm by mass, more preferably 1500 ppm to 3500 ppm, and even more preferably 2000 ppm to 3000 ppm. If the oxygen content is within the above range, it is possible to suppress the adsorption of water while also suppressing changes in properties over time. This allows for a laminated modeling powder 1 with high fluidity and storage stability. Furthermore, an oxide film of moderate thickness is easily formed on the particle surface of the laminated modeling powder 1. This oxide film facilitates the penetration of the binder solution 4.

[0120] Furthermore, if the oxygen content is below the lower limit, the oxide film on the particle surface of the laminated modeling powder 1 may become thinner, potentially causing changes over time. Furthermore, when the laminated modeling powder 1 is used to form the powder layer 31, there is a concern that the permeability of the binder solution 4 in the powder layer 31 may be reduced. On the other hand, if the oxygen content is above the upper limit, water may be easily absorbed, resulting in an increased moisture content and a concern that the flowability of the laminated modeling powder 1 may be reduced. Furthermore, there is a concern that the sintering properties of the laminated modeling powder 1 may be reduced.

[0121] The oxygen content of the laminated molding powder 1 can be measured, for example, in accordance with the general rules for oxygen quantification of metallic materials specified in JIS Z 2613: 2006. Specifically, the measurement can be performed using an oxygen-nitrogen analyzer, TC-300 / EF-300, manufactured by LECO, or an oxygen-nitrogen-hydrogen analyzer, ONH836, manufactured by LECO.

[0122] 2.2.7. Bulk density and tap density

[0123] The bulk density of the powder 1 for laminated molding is preferably 2.50 g / cm 3 Above and 3.50g / cm 3 Below, more preferably 2.70g / cm 3 Above and 3.40g / cm 3 Below, more preferably 3.00 g / cm 3 Above and 3.30g / cm 3 If the bulk density is within the above range, good filling properties can be ensured even in the natural state. Therefore, when the powder layer 31 is formed using the laminated molding powder 1, a powder layer 31 with a high filling rate can be formed. As a result, a dense laminated molding body 6 with high molding accuracy can be obtained, and this laminated molding body 6 can ultimately be used to produce a high-density, high-surface-accuracy metal sintered body.

[0124] The bulk density of the laminated modeling powder 1 is measured according to the apparent density measurement method for metal powders specified in JIS Z 2504:2012. The bulk density is preferably measured using the POWDER TESTER (registered trademark) PT-X, a powder property evaluation device manufactured by Hosokawa Micron Co., Ltd. Furthermore, prior to measuring the bulk density, the laminated modeling powder 1 to be measured is preferably allowed to stand in an environment at 25°C and 50% relative humidity for at least one hour.

[0125] The tap density of the laminated molding powder 1 is preferably 4.20 g / cm 3 Above and 4.90g / cm 3 Below, more preferably 4.40g / cm 3 Above and 4.80g / cm 3 Below, more preferably 4.50 g / cm 3 Above and 4.70g / cm 3 If the tap density is within the above range, a high filling rate can be achieved when the powder layer 31 is flattened on the molding table 23 or compressed by the rollers 25. This allows for a dense, highly accurate stacked molded body 6 to be obtained, ultimately enabling the manufacture of a high-density, highly accurate metal sintered body using this stacked molded body 6.

[0126] The tap density of the laminated modeling powder 1 is measured using a powder property evaluation device, POWDER TESTER (registered trademark), PT-X, manufactured by Hosokawa Micron Co., Ltd. Prior to measuring the tap density, the laminated modeling powder 1 to be measured is preferably allowed to stand in an environment at 25° C. and 50% relative humidity for at least one hour.

[0127] Furthermore, the ratio of the tap density of the laminated molding powder 1 to its bulk density is preferably 1.20 to 1.80, more preferably 1.30 to 1.70, and even more preferably 1.40 to 1.60. When this ratio is within this range, the difference in filling rate between the laminated molding powder 1 in its natural state and the laminated molding powder 1 after vibration, load, etc., can be minimized. This can suppress deformation of the laminated molding body 6 associated with this difference in filling rate. As a result, a metal sintered body with high surface precision can be obtained.

[0128] The ratio may be lower than the above lower limit, but there is a concern that it will be difficult to stably produce the laminated molding powder 1 having such properties. On the other hand, if the ratio exceeds the above upper limit, the difference in filling rate will increase, and there is a concern that the laminated molding body 6 may be deformed.

[0129] Furthermore, the ratio of the tap density to the true density of the laminated molding powder 1 is preferably 0.580 to 0.640, more preferably 0.590 to 0.630, and even more preferably 0.600 to 0.620. When this ratio is within this range, a laminated molding powder 1 having a significantly increased density of the powder layer 31 can be achieved, even with a small particle size. As a result, a high-density metal sintered body with high surface accuracy can be produced. Furthermore, the amount of binder solution 4 used can be reduced while producing the laminated molding body 6.

[0130] Furthermore, if the ratio of the tap density to the true density is below the aforementioned lower limit, there is a concern that the filling properties of the laminated modeling powder 1 may be reduced or the required amount of the binder solution 4 may increase. On the other hand, if the ratio of the tap density to the true density is above the aforementioned upper limit, the manufacturing difficulty of the laminated modeling powder 1 may increase, leading to a concern that the cost may be increased and the manufacturing efficiency may be reduced.

[0131] 3. Method for producing powder for laminated modeling

[0132] Next, an example of a method for producing the laminated modeling powder 1 will be described.

[0133] The laminated molding powder 1 can be produced using any manufacturing method, such as an atomization method. In the atomization method, molten metal is flowed from a crucible and collided with a high-speed jet of fluid, such as a liquid or gas. After colliding with the fluid, the molten metal falls due to inertia, thereby achieving spherical droplets. As a result, despite a relatively small diameter, a metal powder with a high average roundness and a relatively small specific surface area can be produced. Furthermore, reducing the specific surface area can reduce the amount of moisture.

[0134] Atomization methods include water atomization, gas atomization, and rotating water flow atomization, depending on the type of cooling medium and the structure of the device.

[0135] The amount of molten metal flowing down varies depending on the size of the apparatus, but is preferably greater than 1.0 kg / min and less than 20 kg / min, and more preferably greater than 2.0 kg / min and less than 10 kg / min. This optimizes the amount of molten metal flowing down in a given period of time, enabling efficient production of metal powders with a narrow particle size distribution and fully spherical particles. This results in metal powders with a high average roundness and a relatively small specific surface area, despite having a relatively small diameter. Furthermore, reducing the specific surface area can reduce the amount of moisture.

[0136] The temperature of the molten metal in the crucible (casting temperature) is preferably set to Tm + 100°C or higher and Tm + 350°C or lower, relative to the melting point Tm [°C] of the constituent materials of the powder for laminated molding 1, more preferably Tm + 180°C or higher and Tm + 320°C or lower, and even more preferably Tm + 250°C or higher and Tm + 300°C or lower. This ensures that the metal remains in the molten state for a longer period than before, even when finely divided by various atomization methods and solidified. As a result, even small-diameter metal powders with high average roundness and a relatively small specific surface area can be produced.

[0137] In various atomization methods, the outer diameter of the stream of molten metal as it flows down is not particularly limited, but is preferably 3.0 mm or less, more preferably 0.3 mm to 2.0 mm or less, and even more preferably 0.5 mm to 1.5 mm or less. This facilitates uniform contact between the fluid and the molten metal, allowing droplets of appropriate size to be dispersed evenly. As a result, a metal powder with the aforementioned average particle size and good average roundness can be produced with a narrow particle size distribution.

[0138] Furthermore, the produced metal powder may be classified as needed. Examples of the classification method include dry classification such as sieving classification, inertial classification, and centrifugal classification, and wet classification such as sedimentation classification.

[0139] 4. Effects of the above implementation

[0140] As described above, the powder for laminated molding 1 involved in the above embodiment is a powder for laminated molding containing an Fe-based metal material and used for a binder jetting method. In the volume-based cumulative particle size distribution curve measured by the laser diffraction method, when the particle size at the cumulative value from the small diameter side is 10% is set as D10, the particle size at the cumulative value from the small diameter side is 50% is set as D50, and the particle size at the cumulative value from the small diameter side is 90% is set as D90, the particle size D50 of the powder for laminated molding 1 is 1.0 μm or more and less than 15.0 μm, and the particle size difference D90-D10 between the particle size D90 and the particle size D10 is 5.0 μm or more and 18.0 μm or less. In addition, the specific surface area of ​​the powder for laminated molding 1 is 0.05 [m 2 / g] and above 0.25[m 2 / g] or less, and an average circularity of 0.85 to 0.99. Furthermore, when multiple droplets of the evaluation PVP aqueous solution 40, totaling 1.36 mL, were dropped at the same position onto the evaluation powder layer 10 formed by compacting the powder to a relative density of 45% to 47% and a thickness of 10 mm, the penetration depth of the evaluation PVP aqueous solution 40 (penetration depth d) was 110 μm to 250 μm.

[0141] With such a structure, it is possible to obtain the powder 1 for laminated modeling which has both excellent sinterability and fluidity and excellent permeability of the binder solution 4 (aqueous binder solution).

[0142] Furthermore, in the powder 1 for laminated molding according to the above embodiment, the oxygen content is 1000 ppm or more and 4000 ppm or less.

[0143] This structure can suppress moisture adsorption while also minimizing changes in properties over time. This allows for a laminated modeling powder 1 with high fluidity and storage stability. Furthermore, it facilitates the formation of an oxide film of moderate thickness on the particle surfaces of the laminated modeling powder 1. This oxide film facilitates the penetration of the binder solution 4.

[0144] In the laminated molding powder 1 according to the above embodiment, the particle size D50 is 4.0 μm or more and 10.0 μm or less, and the specific surface area is 0.10 [m 2 / g] and above 0.22[m 2 / g] or below.

[0145] With such a structure, it is possible to achieve both sinterability and fluidity of the laminated molding powder 1. As a result, a dense laminated molding body 6 with high molding accuracy can be obtained.

[0146] Furthermore, the powder 1 for laminated molding according to the above embodiment has a moisture content of 200 ppm or less as measured by the Karl Fischer method at 250°C.

[0147] This structure suppresses the decrease in fluidity associated with water adsorption. Consequently, a layered modeling powder 1 with excellent fluidity can be obtained. Furthermore, if the moisture content is within the above range, the chargeability of the layered modeling powder 1 can be controlled within an appropriate range, suppressing the decrease in fluidity associated with charging.

[0148] Furthermore, in the powder 1 for laminated modeling according to the above embodiment, the ratio of the tap density to the bulk density is 1.20 or more and 1.80 or less.

[0149] This structure reduces the difference in filling rate between the laminated molding powder 1 in its natural state and the laminated molding powder 1 after vibration, load, etc., has been applied. This prevents deformation of the laminated molding body 6 associated with this difference in filling rate. Consequently, a metal sintered body with high surface accuracy can be obtained.

[0150] Furthermore, in the powder 1 for laminated molding according to the above embodiment, the Fe-based metal material is precipitation-hardening stainless steel.

[0151] According to such a structure, a metal powder for injection molding capable of producing a metal sintered body having excellent mechanical strength and toughness can be obtained.

[0152] Furthermore, in the powder 1 for laminated modeling according to the above embodiment, the ratio of the tap density to the true density is 0.580 or more and 0.640 or less.

[0153] This structure allows the laminated molding powder 1 to achieve a particularly high density of the powder layer 31, even with a small particle size. Consequently, a high-density, high-surface-precision metal sintered body can be produced. Furthermore, the laminated molding body 6 can be produced while reducing the amount of binder solution 4 used.

[0154] Furthermore, the laminated molding body 6 according to the above embodiment includes the laminated molding powder 1 according to the above embodiment and a binder for binding particles of the laminated molding powder 1 to each other.

[0155] This structure provides a dense and highly accurate laminated molding body 6 by utilizing the high fluidity and filling properties of the laminated molding powder 1. Therefore, for example, by sintering the laminated molding body 6, a high-density and highly accurate metal sintered body can be obtained.

[0156] The laminated molding powder and the laminated molding body of the present invention have been described above based on the illustrated embodiments. However, the present invention is not limited thereto. For example, the laminated molding powder and the laminated molding body of the present invention may be supplemented with arbitrary components in the above embodiments.

[0157] Example

[0158] Next, specific embodiments of the present invention will be described.

[0159] 5. Production of powder for laminated modeling

[0160] By using the water atomization method, laminated modeling powders of Sample Nos. 1 to 23 were produced. The structures of the laminated modeling powders of the respective Sample Nos. are shown in Tables 1 to 4.

[0161] [Table 1]

[0162] Table 1

[0163] Steel Type Classification Steel Type 1 SUS630(17-4PH) Precipitation hardening stainless steel Steel Type 2 SUS316L Austenitic stainless steel Steel Type 3 SUS420J2 Martensitic stainless steel

[0164] 6. Obtaining the characteristics of powder for laminated modeling

[0165] For each layered modeling powder, representative particle size, specific surface area, average circularity, penetration depth of the PVP aqueous solution for evaluation, oxygen content, moisture content, ratio of tap density to bulk density, and ratio of tap density to true density were measured. The measurement results are shown in Tables 2 to 4. In Tables 2 to 4, the layered modeling powder corresponding to the present invention in each sample number is designated as "Example," while the layered modeling powder not corresponding to the present invention is designated as "Comparative Example."

[0166] 7. Evaluation of powder for laminated modeling

[0167] 7.1. Relative density of sintered metals

[0168] Using the laminated molding powder of each sample number, a cubic laminated molding was produced using the binder jetting method. The dimensions of the resulting laminated molding were 40 mm in length, 20 mm in width, and 5 mm in thickness. The binder solution used was the same PVP aqueous solution used for evaluation.

[0169] Next, the resulting laminated body was degreased and then sintered in a furnace. For Steel Type 1, the sintering conditions were set at 1100°C for 3 hours in an argon atmosphere. This yielded a sintered metal body. For Steel Types 2 and 3, the sintering conditions were also selected based on their compositions.

[0170] Next, the density of the resulting metal sintered body was measured. The relative value of the measured density relative to the true density of the laminated molding powder used, i.e., the relative density of the sintered body, was calculated. The calculated relative density was then evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 2 to 4.

[0171] A: Relative density is above 99.0%

[0172] B: Relative density is 98.5% or more and less than 99.0%

[0173] C: Relative density is 98.0% or more and less than 98.5%

[0174] D: Relative density less than 98.0%

[0175] 7.2. Surface roughness of sintered metal bodies

[0176] The surface roughness of the largest surface of the resulting metal sintered body was measured. This surface roughness is the arithmetic mean roughness Ra and was measured according to the method specified in JIS B 0671-1:2002. Furthermore, in Table 2, the surface roughness of each metal sintered body is evaluated relative to the surface roughness of the metal sintered body produced using the laminated molding powder of Sample No. 9. Similarly, in Table 3, the surface roughness of the metal sintered body produced using the laminated molding powder of Sample No. 19 is used as a benchmark, and in Table 4, the surface roughness of the metal sintered body produced using the laminated molding powder of Sample No. 23 is used as a benchmark. The evaluation results are shown in Tables 2 to 4.

[0177] A: The relative value of surface roughness is less than 80% of the reference value

[0178] B: The relative value of surface roughness is 80% or more and less than 90% of the reference value

[0179] C: The relative value of surface roughness is 90% or more and less than 100% of the reference value

[0180] D: The relative value of surface roughness is 100% or more of the reference value

[0181] [Table 2]

[0182] Table 2

[0183]

[0184] [Table 3]

[0185] Table 3

[0186]

[0187] [Table 4]

[0188] Table 4

[0189]

[0190] 7.3. Review of evaluation results

[0191] As shown in Tables 2 to 4, it was found that the metal sintered bodies produced using the powder for laminated molding of each example had high relative density and good surface roughness.

[0192] As described above, it is clear that the powder for laminated molding of the present invention can produce a metal sintered body having a high density and high surface accuracy.

Claims

1. A powder for laminated modeling, characterized in that: Contains Fe-based metal materials and is used in the binder jetting method, In a volume-based cumulative particle size distribution curve measured by a laser diffraction method, where the particle size at which the cumulative value from the small diameter side is 10% is defined as D10, the particle size at which the cumulative value from the small diameter side is 50% is defined as D50, and the particle size at which the cumulative value from the small diameter side is 90% is defined as D90, the particle size D50 is 1.0 μm or more and less than 15.0 μm, and the particle size difference D90-D10 between the particle size D90 and the particle size D10 is 5.0 μm or more and 18.0 μm or less, The specific surface area is 0.05m 2 / g or above and 0.25m 2 / g or less, The average circularity is 0.85 or more and 0.99 or less, When multiple droplets of the evaluation PVP aqueous solution totaling 1.36 mL are dropped at the same position onto an evaluation powder layer formed by compacting powder with a relative density of greater than or equal to 45% and less than or equal to 47% and a thickness of 10 mm, the penetration depth of the evaluation PVP aqueous solution is greater than or equal to 110 μm and less than or equal to 250 μm. PVP is polyvinyl pyrrolidone.

2. The powder for laminated molding according to claim 1, characterized in that The oxygen content is 1000 ppm or more and 4000 ppm or less.

3. The powder for laminated molding according to claim 1 or 2, characterized in that The particle size D50 is 4.0 μm or more and 10.0 μm or less, The specific surface area is 0.10m 2 / g or above and 0.22m 2 / g or less.

4. The powder for laminated molding according to claim 1 or 2, characterized in that The moisture content measured by the Karl Fischer method at 250° C. was 200 ppm or less.

5. The powder for laminated molding according to claim 1 or 2, characterized in that: The ratio of the tap density to the bulk density is 1.20 or more and 1.80 or less.

6. The powder for laminated molding according to claim 1 or 2, characterized in that: The Fe-based metal material is precipitation hardening stainless steel.

7. The powder for laminated molding according to claim 6, characterized in that The ratio of the tap density to the true density is 0.580 or more and 0.640 or less.

8. A stacked shaped body, characterized in that: have: The powder for laminated molding according to claim 1 or 2; and A binder for bonding the particles of the laminated modeling powder to each other.

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