JP3633607B2 - Metal powder for metal stereolithography, method for producing the same, method for producing three-dimensional shaped article by metal stereolithography, and metal stereolithography - Google Patents

Description

  The present invention irradiates a powder layer made of metal powder with a light beam to form a sintered layer, and laminates the sintered layer to obtain a desired three-dimensional shaped object. The present invention relates to a manufacturing method, a manufacturing method of a three-dimensional shaped object by metal stereolithography, and a metal stereolithography object.

  A powder layer formed of metal powder is irradiated with a light beam (directional energy beam, for example, a laser) to form a sintered layer, and a new powder layer is formed on the sintered layer and irradiated with the light beam. Thus, a technique for manufacturing a three-dimensional shaped object by repeating the formation of a sintered layer is known. In this technology, which is called metal stereolithography, by adjusting the energy density of the light beam, the metal powder is solidified after almost completely melting from the state in which there are many gaps (holes) in the modeled object. Forming a molding die or the like that can be obtained up to a state, that is, a molding density (sintered density) of almost 100%, and for this reason, the surface must be smooth. You can also. In addition, it is possible to form the surface with a high density, the inside with a low density, and a medium density in the meantime, and when changing the density in this way, a smooth surface without sacrificing the modeling speed. Can be obtained.

  However, in order to obtain a shaped object having such a density difference between the surface and the interior by metal stereolithography, a metal powder having characteristics different from those of metal powder used for normal powder sintering is required.

  For example, the particle size of the metal powder needs to be smaller than the thickness of the powder layer. At this time, the smaller the particle size, the higher the packing density of the powder, and the better the light beam (laser) absorption during modeling. In addition, the modeling density can be increased and the surface roughness can be decreased. However, if the powder is too fine and agglomerates, the packing density of the powder is decreased, and the powder cannot be spread uniformly and thinly.

  Also, in order to obtain a certain degree of modeling strength, the bonding area between the laser-irradiated modeling part and the underlying sintered layer must be large and the adhesion strength must be high, The bonding area must be large and the adhesion strength must be high.

  Furthermore, the upper surface of the laser-irradiated portion should not rise so much. When the next powder layer is laid to form the next layer, if the bulge amount exceeds the thickness of the powder layer, the formation of the powder layer itself may be difficult.

  In addition, since the metal powder has adhered to the surface of the modeled object, the processing when performing processing such as cutting finish to remove this unnecessary metal powder and expose the high-density surface It is desirable that the property is good.

  Of course, there should be no large cracks in the appearance, and it is desirable that the internal structure should be free of microcracks in consideration of the case of flowing a fluid (cooling water) inside an injection mold or the like.

  Here, a part or all of the metal powder irradiated with the laser is once melted and then rapidly solidified to form a sintered product. If the bonding area is large and the fluidity is large, the rise is small. Therefore, it is desired that the fluidity when melted is high and the wettability is good.

  From this point of view, the present applicant in Japanese Patent Application No. 11-335178 (Japanese Patent Application Laid-Open No. 2001-152204: Patent Document 1) is based on a mixture of chromium molybdenum steel and phosphorous copper, manganese copper and nickel powders. We proposed a metal powder for metal stereolithography. Chrome molybdenum steel is adopted from the viewpoint of strength and toughness, phosphorous copper or manganese copper is adopted from the viewpoint of wettability and fluidity, and nickel is adopted from the viewpoint of strength and workability.

Although the metal powder for metal stereolithography of the above composition can obtain a generally preferable result in terms of obtaining a model having a density difference between the surface and the interior by metal stereolithography, the wet There are some problems during molding in terms of properties and fluidity, and workability (cutability) is not so good, and the most important problem is that as shown in FIG. Many micro cracks are generated in the sintered portion. This microcrack becomes a problem when the obtained shaped article is used as a molding die.
JP 2001-152204 A

  The present invention has been made in view of the above points. The object of the present invention is to provide a metal powder that is excellent in modeling at the time of modeling called metal stereolithography and can obtain a modeled article without microcracks. Therefore, another object is to provide a method for producing a metal powder material that can easily obtain the above metal powder containing a plurality of kinds of powders, and still another object is injection molding. The object is to provide a method for producing a three-dimensional shaped article by metal stereolithography that can easily obtain a shaped article that can be suitably used for a metal mold, and can be used as an injection mold. Is to provide a simple metal stereolithography.

  Accordingly, the metal powder for metal stereolithography according to the present invention forms a sintered layer by irradiating a powder layer made of metal powder with a light beam, and laminates the sintered layer to form a desired three-dimensional shaped object. A metal powder for metal stereolithography, comprising an iron-based powder, a nickel or nickel-based alloy powder, a copper or copper-based alloy powder, and a graphite powder mixed therein Has characteristics. The graphite powder here is used for the purpose of lowering the melting point of the sintered material and improving the sintering density even in the sintering of iron-based powders, etc. Improvement and reduction of the occurrence of microcracks during solidification.

  The blending amount of the graphite powder is desirably within 1 weight percent. When it exceeds 1 weight percent, the effect of reducing microcracks cannot be obtained.

In particular, the amount of iron-based powder is 60 to 90 weight percent, the amount of nickel or nickel-based alloy powder is 5 to 35 weight percent, and the amount of copper or copper-based alloy powder is 5 to 15 weight percent . In some cases , the blending amount of the graphite powder is preferably 0.2 to 1.0 weight percent. The effect of adding graphite powder appears well.

  In addition, satisfying at least one of the conditions of whether the iron-based powder is a chromium molybdenum steel powder or the copper-based alloy powder is a copper-manganese alloy powder improves the characteristics due to the formability and the addition of graphite powder. Gives favorable results.

  The average particle diameter of each of the iron-based powder, nickel or nickel-based alloy powder, and copper or copper-based alloy powder is preferably 5 to 50 μm, but the iron-based powder has an average particle diameter of nickel or In addition, the average particle size of each of the powders of the nickel-based alloy and the copper and / or the copper-based alloy powder is smaller than the average particle size of the iron-based powder, in particular, the nickel-based and nickel-based alloy powder and the copper or copper It is desirable for reducing the microcracks that the average particle diameter of the alloy powder is about 3/4 or less.

  As metal powder for metal stereolithography, it is generally preferred that the powder particles are spherical particles and that the particle size distribution is narrow in order to laminate the powders with high density and uniformity, but graphite powder is added. In this case, the iron-based powder is preferably non-spherical particles, and the nickel or nickel-based alloy powder and the copper or copper-based alloy powder are preferably spherical particles. In particular, when the iron-based powder is a chromium molybdenum steel powder, it is preferably a non-spherical particle having an average particle size of 25 μm or less. This is effective in that the dispersion of the graphite powder is improved and the iron-based powder is well melted.

  As the graphite powder, one having a maximum particle length equal to or less than the average particle diameter of the iron-based powder can be suitably used. When the graphite powder is fine, carbon melts into the iron and lowers the melting point when melted by laser irradiation, so that the flowability at the time of melting is improved and the irregularities on the surface of the sintered layer are reduced.

  It is also preferable that a carbide generating element is mixed. Since precipitation of surplus carbon can be prevented, high-density, high-strength, and high-hardness modeling can be performed, and the surface roughness after cutting finish can be improved by eliminating the precipitated carbon.

  Moreover, the metal powder here may be formed as granulated powder.

  And the manufacturing method of the metal powder for metal stereolithography according to the present invention mixes flake-shaped graphite and grinds the flake-shaped graphite at the time of mixing. In addition, the graphite powder can be uniformly dispersed.

  Moreover, the manufacturing method of the three-dimensional shape molded article by metal stereolithography according to the present invention includes irradiating a desired portion of the powder layer formed of the metal powder described above with a light beam to form a sintered layer at the desired portion. Then, a new powder layer is formed on the sintered layer with the metal powder, and a desired portion of the powder layer is irradiated with a light beam to be integrated with the previously formed sintered layer. It is characterized by forming a desired three-dimensional shaped object by repeatedly forming a new sintered layer, and the metal stereolithography object according to the present invention is manufactured by the above manufacturing method. It has a feature in being.

  According to the above manufacturing method, even if there is a difference in density between the surface and the inside, it is possible to easily manufacture a metal stereolithography product having good characteristics. Of course, there are almost no microcracks in the internal structure, and it can be used for injection molds.

  In the metal stereolithographic metal powder of the present invention, the addition of graphite powder is effective in improving the wettability during melting and reducing the occurrence of microcracks during solidification, and the metal powder for metal stereolithography of the present invention In this production method, the handling of graphite is easy and it can be uniformly dispersed, and the effect of adding graphite can be advantageously derived.

  Moreover, in the manufacturing method of the three-dimensional shaped structure by metal stereolithography according to the present invention, a metal stereolithography object having good characteristics can be easily manufactured even if there is a density difference between the surface and the inside.

  Hereinafter, the present invention will be described in detail based on an embodiment. In addition, although the example of illustration shows what has the removal means 4 for the cutting process in the middle of modeling, and performs the cutting process of the surface of the modeled object modeled so far in the middle of the modeling, this invention is this removal The present invention can also be applied to normal metal stereolithography that does not have the means 4 and does not perform cutting work during modeling.

  FIG. 2 shows an example of an apparatus for metal stereolithography. By using a squeezing blade 21, the metal powder supplied on a lifting table 20 that moves up and down by a cylinder in a space surrounded by an outer periphery is smoothed. The powder layer forming means 2 for forming the powder layer 10 having a predetermined thickness Δt1 and the powder outputted from the laser oscillator 30 are irradiated onto the powder layer 10 through a scanning optical system such as a galvano mirror 31 to burn the metal powder. And a removal layer 4 formed by providing a milling head 41 via an XY drive mechanism 40 at the base portion of the powder layer formation unit 2. ing.

  As shown in FIG. 3, the manufacture of the three-dimensional shaped article in this product is a modeling base 22 on the upper surface of the lifting table 20 which is an adjusting means for adjusting the relative distance between the sintered layer forming means and the sintered layer. The first powder layer 10 is formed by supplying metal powder to the surface with the blade 21 and at the same time with the blade 21, and a portion of the powder layer 10 to be cured is irradiated with a light beam (laser) L to produce powder. Is sintered to form the sintered layer 11 integrated with the base 22.

  After that, the lifting table 20 is slightly lowered, the metal powder is supplied again, and the blade 21 is used to form the second powder layer 10. A light beam (laser) is applied to the portion of the powder layer 10 to be cured. L is irradiated to sinter the powder to form the sintered layer 11 integrated with the lower sintered layer 11.

  By lowering the elevating table 20 to form a new powder layer 10 and irradiating a light beam to make the required portion a sintered layer 11, a desired three-dimensional shaped object is manufactured. Yes, a carbon dioxide laser can be suitably used as the light beam, and the thickness Δt1 of the powder layer 10 is about 0.05 mm when the obtained three-dimensional shaped object is used for a molding die or the like. It is preferable to do this.

  The irradiation path of the light beam is created in advance from three-dimensional CAD data. That is, contour shape data of each cross section obtained by slicing STL data generated from a three-dimensional CAD model at an equal pitch (0.05 mm pitch when Δt1 is 0.05 mm) is used. At this time, irradiation with a light beam is performed so that at least the outermost surface of the three-dimensional shaped object can be sintered at a high density (porosity of 5% or less), and the inside is baked to a low density. In other words, the shape model data is preliminarily divided into the surface layer part and the inside, and the inside is a sintering condition that becomes porous, and the surface layer part is a condition that the powder almost melts and becomes high density By irradiating with a light beam, a shaped object having a dense surface can be obtained at high speed.

  Then, the powder layer 10 is formed and the light beam is irradiated to repeatedly form the sintered layer 11. The total thickness of the sintered layer 11 is, for example, the tool length of the milling head 41. When the required value obtained from the above is reached, the removal means 4 is once activated to cut the surface of the shaped object that has been shaped so far. For example, if the tool (ball end mill) of the milling head 41 is capable of cutting with a diameter of 1 mm, an effective blade length of 3 mm and a depth of 3 mm, and the thickness Δt1 of the powder layer 10 is 0.05 mm, 60 layers of fired When the binder layer 11 is formed, the removing means 4 is operated.

  By removing the low-density surface layer of the powder adhering to the surface of the modeled object by cutting by the removing means 4, the high-density part is entirely exposed on the surface of the modeled object by cutting into the high-density part.

  The cutting path by the removing means 4 is created in advance from three-dimensional CAD data in the same manner as the light beam irradiation path. At this time, the machining path is determined by applying contour processing, but the Z-direction pitch does not need to stick to the lamination pitch at the time of sintering, and in the case of a gentle inclination, by interpolating with a finer Z-direction pitch, Keep a smooth surface.

  In manufacturing a three-dimensional shaped object in such metal stereolithography, what kind of metal powder is used as described above has a great influence on the point of formability and the quality of the object. However, from the above-mentioned points required as a metal powder for metal stereolithography, a powder comprising iron-based powder, nickel or nickel-based alloy powder, copper or copper-based alloy powder is used. In the present invention, a mixture of graphite powder is used.

  In iron-based powder sintering and the like, although graphite is added for the purpose of lowering the melting point of the sintered material and improving the sintering density, a light beam is applied to the extremely thin powder layer 10 having a thickness Δt1 of 0.05 mm. In the case of melting by irradiation, there has been no attempt so far to add graphite, but the present inventors have improved wettability during melting and solidification of high-density portions. It has been found that the addition of graphite powder is very effective in reducing the occurrence of microcracks. The reason why the addition of graphite powder reduces the occurrence of microcracks is not clear, but a state in which a mass of graphite is scattered in the cross section after modeling (black dots in FIG. 1 are seen as graphite).

  The blending amount of the graphite powder depends on the blending of other metal powder materials, but is preferably within about 1 weight percent, particularly 60 to 90 weight percent of the iron-based powder, nickel or nickel-based alloy When the amount of the powder is 5 to 35 weight percent and the amount of the copper or copper alloy powder is 5 to 15 weight percent, the amount of the graphite powder is 0.2 to 1.0 weight percent. It is desirable. When the blending amount of the graphite powder exceeds 1 weight percent, the effect of reducing microcracks is completely lost, and microcracks equivalent to the case of not adding are generated.

  As the metal material, chromium-molybdenum steel powder can be suitably used as the iron-based powder, and copper-manganese alloy powder as the copper-based alloy powder. When at least one of these two conditions is satisfied, it is possible to more reliably improve the characteristics by adding graphite powder.

  Further, the blending amount of chromium molybdenum steel powder is 60 to 80% by weight, the blending amount of nickel powder is 15 to 25% by weight, the blending amount of copper manganese alloy powder is 5 to 15% by weight, and the blending amount of graphite powder is 0.00. When the content was 2 to 0.75 weight percent, no microcracks were generated in the high density portion, and good formability could be obtained in both the high density portion and the low density portion.

  In addition, it is desirable that the average particle diameter of each of the iron-based powder, nickel or nickel-based alloy powder, and copper or copper-based alloy powder is 5 to 50 μm. Therefore, when the thickness Δt1 of the powder layer 10 is 0.05 mm, the average particle diameter is preferably about 30 μm.

  However, as a metal powder for metal stereolithography, it is generally preferable that the powder particles are spherical particles and that the particle size distribution is narrow in order to uniformly stack the powders. However, when graphite powder is added, the iron-based powder is non-spherical particles, the powder of nickel or nickel-based alloy and the powder of copper or copper-based alloy are spherical particles, especially the iron-based powder. Chrome-molybdenum steel powder with non-spherical particles having an average particle size of 25 μm or less, and approximately 3/4 or less of the average particle size of each powder of nickel or nickel-based alloy powder and copper or copper-based alloy powder In this case, good results could be obtained.

[Example]
Chrome-molybdenum steel SCM440 powder (see FIG. 4) with non-spherical particles and an average particle size of 20 μm, nickel Ni powder (see FIG. 5) with spherical particles and an average particle size of 30 μm, and spherical particles with an average particle size of 30 μm copper-manganese alloy CuMnNi (for example, Cu-10% Mn-3% Ni) powder (see FIG. 6) is prepared, and the following six types of metal stereolithographic metal powders with different amounts of graphite C are prepared. Formed. Each% is% by weight.
a. 70% SCM440-21% Ni-9% CuMnNi
b. (70% SCM440-21% Ni-9% CuMnNi) + 0.2% C
c. (70% SCM440-21% Ni-9% CuMnNi) + 0.4% C
d. (70% SCM440-21% Ni-9% CuMnNi) + 0.5% C
e. (70% SCM440-21% Ni-9% CuMnNi) + 0.75% C
f. (70% SCM440-21% Ni-9% CuMnNi) + 1.0% C
Metal stereolithography was performed using these six types of metal powders a to f. The thickness of the powder layer was 0.05 mm, and the laser used was a carbon dioxide laser (90% output of 200 W output). When sintered at a laser scan speed of 75 mm / sec and a scan pitch of 0.25 mm, A number of microcracks were observed in those not added, whereas no microcracks were observed in those added with 0.5% of graphite d (see FIG. 1). In addition, only a few microcracks were observed in the case where 0.4% of graphite was added. And in what added 0.2% of graphite and what added 0.75%, the reduction effect of a microcrack can be confirmed compared with the thing which does not add graphite, and 1% of graphite was added. In the samples, microcracks were observed which were almost the same or slightly less than those not added with graphite.

  The high density part has a laser scan speed of 75 mm / sec and a scan pitch of 0.25 mm, the medium density part has a laser scan speed of 150 mm / sec and a scan pitch of 0.5 mm, and the low density part has a laser scan speed of 200 mm / sec. When a three-dimensional shaped object having a density difference is formed by irradiating the powder layer with laser every other layer at a pitch of 0.3 mm, the fluidity is enhanced in the case of adding graphite powder. We were able to confirm from the small amount of.

  In addition, in the metal powder having the same composition as the above d, a chrome molybdenum steel powder having a spherical particle shape and an average particle diameter of 30 μm is the same as that of other non-ferrous metal powder, and the powder layer has a thickness of 0.05 mm, a carbon dioxide laser (output) Sintered under the conditions of 90% output of 200 W), laser scan speed of 75 mm / sec, and scan pitch of 0.25 mm, a few micro cracks are observed and pores are generated compared to the above d. Although the modeling density was slightly reduced, a generally good model could be obtained.

  Moreover, when sintered under the same conditions using copper phosphorus CuP alloy powder (spherical particles and average particle size of 30 μm) instead of the copper-manganese alloy in the composition of d, generation of microcracks was observed, Unevenness was generated on the upper surface of the sintered layer, which hindered the formation of the next powder layer. There was also a problem in terms of bending strength.

  Further, instead of the copper-manganese alloy in the blend of d, a copper phosphorus alloy powder (spherical particles having an average particle size of 30 μm) is used, and the chromium molybdenum steel powder has a spherical particle shape and an average particle size of other nonferrous metal powders. When the same 30 μm material was used, a better result was obtained than a combination of a non-spherical particle-shaped chromium molybdenum steel having an average particle size of 20 μm and a spherical particle-shaped copper phosphorus CuP alloy powder having an average particle size of 30 μm. Although it could be obtained, the occurrence of microcracks was observed.

  The combination of copper-phosphorus alloy powder and the combination of copper-manganese alloy powder differ in the factors that cause microcracking. In the case of mixing copper-manganese alloy powder, the micro-cracks are caused by insufficient melting during laser sintering. It is considered that cracks are generated, and it is considered that the use of a chromium molybdenum steel powder having an average particle size smaller than that of other nonferrous metal powders promotes melting and reduces the occurrence of microcracks.

  In addition, when non-spherical particles are used as the chromium molybdenum steel powder, the graphite powder is more effectively dispersed on the surface of each particle of the chromium molybdenum steel powder than when the spherical particle is used. The addition seems to work more effectively.

  By the way, it is addition of the graphite powder, but flake-like graphite (see FIG. 7) is added to the iron-based powder and nickel or nickel-based alloy powder and copper or copper-based alloy powder. When mashing was performed using a mortar for mixing, no graphite powder was observed in the mixed powder (see FIG. 8). This is thought to be due to the effective dispersion of graphite on the surface of metal powder, especially non-spherical chrome molybdenum steel powder, and better formability can be obtained than when graphite powder is simply mixed with metal powder. In addition, there were fewer microcracks.

  In addition, when graphite powder whose maximum particle size is less than the average particle diameter of iron-based powder, especially 10 μm or less is used, when carbon is melted by laser irradiation, carbon enters the iron and the melting point is reduced. Since the carburizing effect can be obtained and the flowability at the time of melting is improved, the unevenness on the surface of the sintered layer can be reduced.

  Incidentally, ultrafine particles of graphite powder with a maximum length of 1 to several μm can be obtained as carbon black, which is black fine powder obtained by incomplete combustion or thermal decomposition of natural gas or liquid hydrocarbon, and jet mill pulverization It can also be obtained by law.

  Further, as described above, the black dots in FIG. 1 are obtained by precipitating graphite, but it is also preferable that carbide forming elements are mixed in advance in iron. When carbide generating elements such as chromium Cr, molybdenum Mo, tungsten W, and vanadium V are mixed, carbon to be precipitated when solidifying from a molten state becomes carbide by bonding with the carbide generating elements. Carbon deposition can be prevented.

  FIG. 9 is an SEM photograph of the above example d when tungsten W powder is added ((70% SCM440-21% Ni-9% CuMnNi) + 0.5% C + 0.5% W). It is a SEM photograph when the system powder SCM440 is changed to SKH steel powder containing a large amount of carbide forming elements ((70% SKH51-21% Ni-9% CuMnNi) + 0.5% C). Each% is% by weight. Carbon deposition is clearly reduced compared to that according to Example d shown in FIG. When the carbon precipitation is reduced in this way, it is possible to perform a high-density, high-strength, high-hardness modeling, and the absence of precipitated carbon can also improve the surface roughness after cutting finish. .

  The metal powder in each of the above examples may be formed as a granulated powder. It becomes easy to handle. In addition, a three-dimensional shaped object obtained by performing metal stereolithography using such a metal powder has sufficient characteristics to be used as an injection mold.

It is a cross-sectional photograph of magnification 25 times of the metal stereolithography thing manufactured with the metal powder of an example of embodiment of this invention. It is a schematic perspective view of an example of the apparatus which performs metal stereolithography using the metal powder same as the above. It is explanatory drawing same as the above. It is a SEM photograph of the non-spherical particle-like chromium molybdenum steel powder same as the above. It is a SEM photograph of the spherical particle-like nickel powder same as the above. It is a SEM photograph of the spherical particulate copper manganese alloy powder same as the above. It is a SEM photograph of flaky graphite same as the above. It is a SEM photograph of a mixture same as the above. It is a cross-sectional photograph of magnification 25 times of the metal stereolithography thing manufactured with the metal powder which added the carbide | carbonized_material production | generation element. It is a cross-sectional photograph of magnification 25 times of the metal stereolithography thing manufactured with the metal powder using the iron-type powder containing many carbide | carbonized_material generation elements. It is a cross-sectional photograph of magnification 25 times of the metal stereolithography thing manufactured with the metal powder of the prior art example.

Claims (15)

  A metal powder for metal stereolithography, which forms a sintered layer by irradiating a powder layer made of metal powder to form a sintered layer and obtains a desired three-dimensional shaped object by laminating the sintered layer. A metal powder for metal stereolithography, characterized in that it is made of a nickel-based powder, nickel or a nickel-based alloy powder, copper or a copper-based alloy powder, and graphite powder is mixed.   The metal powder for metal stereolithography according to claim 1, wherein the amount of the graphite powder is within 1 weight percent. The amount of iron-based powder is 60 to 90 percent by weight, the amount of nickel or nickel-based alloy powder is 5 to 35 percent by weight, and the amount of copper or copper-based alloy powder is 5 to 15 percent by weight. The metal powder for metal stereolithography according to claim 1 or 2, wherein the compounding amount of the graphite powder is 0.2 to 1.0 weight percent.   The iron-based powder satisfies at least one of the conditions as to whether the iron-based powder is a chromium molybdenum steel powder or the copper-based alloy powder is a copper-manganese alloy powder. Metal powder for metal stereolithography. 5. The average particle diameter of each powder of iron-based powder, nickel or nickel-based alloy powder and copper or copper-based alloy powder is 5 to 50 μm, according to claim 1. Metal powder for metal stereolithography of description. The average particle diameter of the iron-based powder is smaller than the average particle diameter of each powder of nickel or a nickel-based alloy powder and copper or a copper-based alloy powder . Metal powder. 7. The metallic light according to claim 6, wherein the average particle diameter of the iron-based powder is approximately 3/4 or less of the average particle diameter of the nickel or nickel-based alloy powder and the copper or copper-based alloy powder. Metal powder for modeling. The iron-based powder is non-spherical particles, nickel or a nickel-based alloy powder and copper or copper-based alloy powders are spherical particles, or any one of claims 5 to 7. Metal powder for metal stereolithography. 9. The metal powder for metal stereolithography according to claim 8, wherein the iron-based powder is chrome molybdenum steel powder and has an average particle diameter of 25 μm or less . The metal powder for metal stereolithography according to any one of claims 1 to 9, wherein the maximum length of the graphite powder particles is equal to or less than the average particle diameter of the iron-based powder. It forms as granulated powder, The metal powder for metal stereolithography of any one of Claims 1-10 characterized by the above-mentioned. The metal powder for metal stereolithography according to any one of claims 1 to 11, wherein a carbide generating element is mixed . It is a manufacturing method of the metal powder for metal stereolithography of any one of Claims 1-12, Comprising: Iron-type powder, nickel or a nickel-type alloy powder, copper or a copper-type alloy powder, On the other hand, a method for producing metal powder for metal stereolithography, characterized in that flaky graphite is mixed and flaked graphite is ground during mixing. A light beam is irradiated to a desired portion of the powder layer formed of the metal powder according to any one of claims 1 to 12 to form a sintered layer at a desired portion, and then on the sintered layer. Forming a new powder layer with the above metal powder and irradiating a desired portion of the powder layer with a light beam to form a new sintered layer integrated with the previously formed sintered layer. A method for producing a three-dimensional shaped object by metal stereolithography, wherein a desired three-dimensional shaped object is formed by repetition. A metal stereolithographic product manufactured by the method for producing a three-dimensional modeled product by metal stereolithography according to claim 14.