WO2018216461A1

WO2018216461A1 - Sintered member and method for producing same

Info

Publication number: WO2018216461A1
Application number: PCT/JP2018/017803
Authority: WO
Inventors: 朝之伊志嶺; 繁樹江頭; 宗巨野田
Original assignee: 住友電気工業株式会社; 住友電工焼結合金株式会社
Priority date: 2017-05-26
Filing date: 2018-05-08
Publication date: 2018-11-29
Also published as: US20210162499A1; JPWO2018216461A1

Abstract

Provided is a method for producing a sintered member, the method comprising: a step for preparing raw material powder containing iron-based powder; a step for pressure molding the raw material powder to form a columnar or cylindrical powder compact having a relative density of at least 97%; and a step for sintering the powder compact, wherein the raw material powder contains at least one among a mixed powder containing pure iron powder and Ni powder, and an iron alloy powder containing Ni as an additive element, and the sum content of Ni powder in the raw material powder and Ni as an additive element is at least 1 mass%.

Description

Method for manufacturing sintered member

The present disclosure relates to a method for manufacturing a sintered member. This application claims priority based on Japanese Patent Application No. 2017-105088 filed on May 26, 2017, and incorporates all the contents described in the aforementioned Japanese Patent Application.

As a method for producing a sintered member used for automobile parts or general machine parts, a method for producing a sintered body of Patent Document 1 is known. The method for manufacturing the sintered body includes a step of pressure-molding a metal powder to produce a molded body, a step of temporarily firing the molded body, a step of machining the temporary fired body, a machining step, And a step of firing. In the step of producing a molded body, the pressure during pressure molding is set to 100 MPa to 1500 MPa.

JP 2007-77468 A

The method for producing a sintered member according to the present disclosure is as follows.
Preparing a raw material powder containing iron-based powder;
A step of pressure-molding the raw material powder to form a cylindrical or cylindrical powder compact having a relative density of 97% or more;
A step of sintering the green compact.
The raw material powder includes at least one of a mixed powder containing pure iron powder and Ni powder, and an iron alloy powder containing Ni as an additive element,
The total content of the Ni powder in the raw material powder and Ni as the additive element is 1% by mass or more.

FIG. 1 is a graph showing the relationship between molding pressure and molding density in Test Example 1. FIG. 2 is a graph showing the relationship between molding density and tensile strength in Test Example 1.

<< Description of Embodiments of the Present Disclosure >>
First, the contents of the embodiments of the present disclosure will be listed and described.

(1) A method for manufacturing a sintered member according to one aspect of the present disclosure includes:
Preparing a raw material powder containing iron-based powder;
A step of pressure-molding the raw material powder to form a cylindrical or cylindrical powder compact having a relative density of 97% or more;
A step of sintering the green compact.
The raw material powder includes at least one of a mixed powder containing pure iron powder and Ni powder, and an iron alloy powder containing Ni as an additive element,
The total content of the Ni powder in the raw material powder and Ni as the additive element is 1% by mass or more.

According to the above configuration, a sintered member having high density and high strength can be manufactured. This is because the relative density of the green compact is 97% or more and the green compact shrinks due to sintering, so the relative density of the sintered member is larger than the relative density of the green compact. This is because the strength can be improved by the relative density of the sintered member being high.

(2) As one form of the manufacturing method of the said sintered member, providing the process of cutting the said compacting body after the said formation process and before the said sintering process is mentioned.

According to the above configuration, a sintered member having a high density and a complicated shape can be easily manufactured. The compacted body contains 1% by mass of Ni that lowers the machinability as a powder or 1% by mass or more as an additive element of the alloy, as compared with a sintered member or a melted material having the same composition. Easy to cut because it is soft and has low stickiness. In addition, although the green compact is softer than a sintered member or melted material, the relative density is very high and the strength is high to some extent.

<< Details of Embodiments of the Present Disclosure >>
Details of embodiments of the present disclosure are described below.

[Method for producing sintered member]
The method for manufacturing a sintered member according to the embodiment includes a step of preparing raw material powder (raw material preparation step), a step of pressing the raw material powder to form a green compact (molding step), and compacting. And a step of sintering the body (sintering step). One of the features of this method for producing a sintered member is that a specific raw material powder is prepared in the raw material preparation step, and a green compact that satisfies a specific relative density in the forming step is produced. Hereinafter, details of each process will be described.

[Raw material preparation process]
The raw material preparation step prepares a raw material powder including an iron-based powder having a plurality of iron-based particles. The iron-based refers to pure iron or an iron alloy containing iron as a main component. The raw material powder includes any one of a mixed powder containing Ni as a powder, an iron alloy powder containing Ni as an additive element, and a composite powder containing both the mixed powder and the iron alloy powder.

(Mixed powder)
The mixed powder includes pure iron powder and Ni powder. The content of the pure iron powder is, for example, 90% by mass or more, further 95% by mass or more when the raw material powder is 100% by mass. The content of the Ni powder is 1% by mass or more when the raw material powder is 100% by mass. When the content of the Ni powder is 1% by mass or more, the hardenability is improved and the mechanical properties of the sintered member can be improved. The content of the Ni powder is further 2% by mass or more and 10% by mass or less. This mixed powder becomes an iron-based alloy by sintering in a subsequent sintering step.

The mixed powder may further contain a powder of an alloying element that becomes an iron-based alloy by sintering in a subsequent sintering step. Examples of the alloying element include at least one selected from Cu, Sn, Cr, Mo, Mn, and C. The alloying element contributes to the improvement of the mechanical properties of the sintered member. Among the alloying elements, the content of Cu, Sn, Cr, Mn and Mo powders is more than 0% by mass and 5.0% by mass or less, further 0.1% by mass when the raw material powder is 100% by mass. % Or more and 2.0% by mass or less. On the other hand, the content of the C powder is more than 0% by mass and 2.0% by mass or less, and further 0.1% by mass or more and 1.0% by mass or less when the raw material powder is 100% by mass.

(Iron alloy powder)
The iron alloy powder has a plurality of iron alloy particles containing iron as a main component and Ni as an additive element.
The iron content is 90% by mass or more, and more preferably 95% by mass or more when the iron alloy is 100% by mass. The content of Ni, when the iron alloy is 100% by mass, is 1% by mass or more, and further 2% by mass or more and 10% by mass or less.

The iron alloy may further contain at least one additive element selected from Cu, Sn, Cr, Mo, Mn, and C. Iron alloys are allowed to contain inevitable impurities. Specific iron alloys include Fe—Ni—Mo alloy, Fe—Ni—Mo—C alloy, Fe—Ni—C alloy, Fe—Ni—Mo—Cr alloy, Fe—Ni—Mo—Mn. Alloy, Fe—Ni—Cr alloy, Fe—Ni—Cu alloy, Fe—Cu—Ni—Mo alloy, Fe—Ni—Mo—Cu—C alloy and the like. The total content of Cu, Sn, Cr, Mn and Mo in the iron alloy is more than 0% by mass and 5.0% by mass or less, and further 0.1% by mass to 2.0% by mass. The content of C in the iron alloy is more than 0% by mass and 2.0% by mass or less, and further 0.1% by mass to 1.0% by mass. C may not be included as an additive element of the iron alloy but may be included in the raw material powder as a powder. That is, the raw material powder may contain C powder in addition to the iron alloy powder.

(Composite powder)
The composite powder includes both the above mixed powder and the above iron alloy powder. That is, the composite powder includes pure iron powder, Ni powder, and iron alloy powder having a plurality of iron alloy particles containing iron as a main component and Ni as an additive element. The total content of pure iron and iron contained in the iron alloy in the raw material powder is 90% by mass or more, further 95% by mass or more when the total raw material powder is 100% by mass. The total content of Ni contained as an additive element in the Ni powder and the iron alloy in the raw material powder is 1% by mass or more when the entire raw material powder is 100% by mass, and further 2% by mass or more and 10% by mass or less. Is mentioned.

As the iron-based powder, water atomized powder, reduced powder, gas atomized powder, carbonyl powder and the like can be used. As for the average particle diameter of iron-type powder, 20 micrometers or more and 200 micrometers or less are mentioned, for example. If the average particle diameter of the iron-based powder is within the above range, it is easy to handle and pressure forming. In particular, the fluidity of the iron-based powder can be easily ensured by setting the average particle size of the iron-based powder to 20 μm or more. By setting the average particle size of the iron-based powder to 200 μm or less, it is easy to obtain a sintered body having a dense structure. The average particle diameter of the iron-based powder is further 50 μm or more and 150 μm or less. The average particle size of the iron-based powder is a particle size (D50) at which the cumulative volume in the volume particle size distribution measured by a laser diffraction particle size distribution measuring device is 50%.

The raw material powder may contain at least one of a lubricant and an organic binder. However, it is preferable that the lubricant and the organic binder are as small as possible. As for the total content, 0.1 mass% or less is mentioned. By doing so, even if the raw material powder contains at least one of a lubricant and an organic binder, the proportion of the metal powder contained in the molded body can be increased, so that a dense compacted green body can be easily obtained. When the lubricant and the organic binder are not contained, it is not necessary to degrease the green compact in a subsequent process.

[Molding process]
In the forming step, the raw material powder is pressure-molded to produce a green compact with a relative density of 97% or more. The relative density is further preferably 98% or more, and particularly preferably 99% or more. Examples of the shape of the green compact include a shape that conforms to the final shape of the sintered member, a shape that is suitable for subsequent cutting, and specifically, a columnar shape, a cylindrical shape, and the like. For the production of the green compact, an appropriate molding device (mold) that can be molded into the above-mentioned shape is used. Specifically, it is preferable to use a mold capable of uniaxial pressing so as to be press-formed along the axial direction of a column or cylinder. Uniaxial pressurization includes using a die having a die having openings on the top and bottom and a pair of punches fitted into the top and bottom openings. The raw material powder is filled into the cavity of the die of this mold, and the raw material powder in the cavity is compressed by the upper punch and the lower punch to produce a compacted body.

The molding pressure (surface pressure) is 1560 MPa or more. By increasing the molding pressure, a green compact with a high relative density can be produced. The molding pressure is further preferably 1660 MPa or more and 1760 MPa or more, and particularly preferably 1860 MPa or 1960 MPa or more. There is no particular upper limit on the molding pressure.

The molding step is preferably performed by a mold (external) lubrication method in which a lubricant is applied to the inner peripheral surface of the mold (the inner peripheral surface of the die or the pressing surface of the punch). Then, it is easy to prevent the raw material powder from sticking to the mold. As the lubricant, for example, higher fatty acid, metal soap, fatty acid amide, higher fatty acid amide and the like can be used. Examples of the metal soap include zinc stearate and lithium stearate. Examples of fatty acid amides include stearic acid amide, lauric acid amide, and palmitic acid amide. Examples of the higher fatty acid amide include ethylene bis stearic acid amide.

The relative density of the green compact to be produced is preferably 98% or more, particularly preferably 99% or more. The relative density of the green compact is obtained from “{(molding density of the green compact) / (true density of the green compact)} × 100”. The compacting density of the compacted body is determined by immersing the compacted body in oil, “oil content density × {(mass of compacted body before oil impregnation) / (mass of compacted compact after oil impregnation)}” Ask from. The oil impregnation density is a value obtained by dividing the mass of the green compact after oil impregnation by the volume of the green compact.

Further, the relative density of the green compact can be obtained by image analysis of the cross section of the green compact with commercially available image analysis software. First, in the cross section of the green compact, images of 10 or more observation fields are acquired. The cross section may be an arbitrary cross section, and 10 or more cross sections may be taken as one visual field per cross section, or a plurality of visual fields may be taken per cross section. The size of each visual field is 500 μm × 600 μm. The image of each observation visual field is binarized to obtain the area ratio of the metal in each observation visual field, and the area ratio is regarded as the relative density of each observation visual field. And the average value of the relative density of all the observation visual fields is calculated | required, and it is set as the relative density of a compacting body.

[Sintering process]
In the sintering step, the green compact is sintered. By this sintering, a sintered member in which the particles of the metal powder are brought into contact with each other is obtained. The relative density of this sintered member is over 97%. Since the green compact has a relative density of 97% or more and the green compact shrinks due to sintering, the relative density of the sintered member after sintering is greater than the relative density of the green compact. is there. Since the green compact has a very high density, the amount of shrinkage of the green compact by sintering is very small, but the relative density of the sintered member exceeds the relative density of the green compact.

Sintering conditions can be appropriately selected according to the composition of the raw material powder. As for sintering temperature, 1100 degreeC or more and 1400 degrees C or less are mentioned, for example, Furthermore, 1200 degreeC or more and 1300 degrees C or less are mentioned. As for sintering time, 15 minutes or more and 150 minutes or less are mentioned, for example, Furthermore, 20 minutes or more and 60 minutes or less are mentioned. Known conditions can be applied to the sintering conditions.

[Other processes]
In addition to the raw material preparation step, the molding step, and the sintering step, the sintered member manufacturing method includes a step of cutting the molded body (molded body processing step), and a step of carburizing and tempering the sintered member. It is possible to include at least one step of (heat treatment step) and a step of finishing the sintered member (finishing step).

(Molded body processing process)
In the green body processing step, the green body is cut after the molding step and before the sintering step. In the cutting process, the green compact is processed into a predetermined shape using a cutting tool. Since the green compact before sintering is cut, a sintered member having a high density and a complicated shape can be easily manufactured. The green compact does not contain Ni, which lowers the machinability, as a powder, or contains 1% by mass or more as an additive element of the alloy. Easy to cut because it is soft and soft. In addition, the green compact is softer than the sintered member or melted material, but has a relatively high relative density and a certain degree of strength. Therefore, it is easy to suppress the occurrence of chips and cracks due to cutting. The green compact has only the raw material powder hardened by molding, and the metal powder particles are in mechanical contact with each other. In the sintered member, particles of the metal powder are diffusion-bonded and firmly bonded by sintering. When the melted material is the same size as the green compact, it is a material that is much larger and integrated than the metal particles that make up the green compact.

Especially, the processing speed to the compacted body using the mixed powder can be made faster than the processing speed to the compacted body using the alloy powder. For example, when dry cutting is performed on a powder compact using an alloy powder and a powder compact using a mixed powder using a hob made of powder HSS, the maximum peripheral speed of the tool ( The cutting speed) is 350 m / min in the case of processing the alloy powder into a green compact, and 450 m / min in the case of processing the mixed powder into a green compact. Similarly, the maximum peripheral speed of the tool is 150 m / min in the case of processing into a molten material, and 150 m / min in the case of processing into a sintered member.

Examples of the cutting process include a turning process and a turning process. The milling includes drilling. Examples of the cutting tool include drilling, reamer, turning, milling, end mill, turning, cutting tool, and other types of cutting tips in the case of drilling. In addition, a hob, a broach, a pinion cutter, or the like may be used, or a machining center that can automatically perform a plurality of types of processing may be used.

Before being subjected to cutting, a volatile solution or a plastic solution in which an organic binder is dissolved may be applied or immersed on the surface of the green compact. If it does so, it is easy to suppress the crack and notch | chip of the surface layer of the compacting body at the time of cutting. Examples of the organic binder include polyethylene, polypropylene, polymethyl methacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polyether, polyvinyl alcohol, vinyl acetate, paraffin, and various waxes.

Cutting may be performed while applying a compressive stress to the green compact in a direction that cancels the tensile stress acting on the green compact. If it does so, it will be easy to suppress a crack and a chip of a compacting object. For example, when forming a processed hole in a green compact with a broach, strong tensile stress acts near the exit of the processed hole when the broach penetrates the green compact. In this case, a plurality of green compacts may be stacked in multiple stages. It is preferable to dispose a dummy green compact or a plate material under the lowest green compact. If a plurality of green compacts are stacked in multiple stages, the lower surface of the green compact on the upper side is pressed against the upper surface of the lower green compact, and compressive stress acts on the lower surface. If broaching is performed from above the multi-stage stacked compacts, cracks and chips near the exit of the processed holes formed on the lower surface of the compact can be effectively prevented. Moreover, when forming a processing groove in a compacting body with a milling cutter, a strong tensile stress acts near the exit of the processing groove. In this case, it is possible to arrange a plurality of green compacts in the direction of milling and to apply a compressive stress to the portion serving as the exit of the processing groove.

(Heat treatment process)
In the heat treatment step, the sintered member is carburized and tempered. Thus, the mechanical properties of the sintered member, particularly the hardness and toughness, are improved.

(Finishing process)
In the finishing process, the surface roughness of the sintered member is reduced, and the size of the sintered member is adjusted to the design dimension. For example, the grinding | polishing process etc. to the surface of a sintered member are mentioned.

[Usage]
The sintered member manufacturing method according to the embodiment can manufacture a sintered member having high density and high strength. Further, a sintered member having a high density and a complicated shape can be easily manufactured. Therefore, the method for manufacturing a sintered member according to the embodiment is suitably used for manufacturing various general structural parts (sintered parts such as mechanical parts such as sprockets, rotors, gears, rings, flanges, pulleys, and bearings). it can.

(Sintered member)
The sintered member is formed by bonding a plurality of metal particles, and the relative density exceeds 97%. This sintered member can be manufactured by the above-described method for manufacturing a sintered member (raw material preparation step, molding step and sintering step). Since the relative density of the molded body is 97% or more, the relative density of the sintered member that has undergone the subsequent sintering step also exceeds 97%. The method for measuring the relative density is the same as the method for measuring the relative density of the green compact. This sintered member has no substantial change in density within a range of 1 mm from the surface thereof. That is, the density is substantially uniform. This is because no rolling process is applied to the sintered member. Further, the stream structure in which the metal particles are stretched is not formed in the metal structure of the sintered member. This is because the sintered member is not forged.

<< Test Example 1 >>
Sintered members were prepared and the relative density and strength of the sintered members were evaluated.

[Sample No. 1-1-No. 1-3, no. 1-101-No. 1-103]
Sample No. 1-1-No. 1-3, no. 1-101-No. The sintered member 1-103 was produced through the raw material preparation step, the forming step, and the sintering step in the same manner as the above-described sintered member manufacturing method.

[Raw material preparation process]
As the raw material powder, an iron alloy powder and a carbon powder prepared by a water atomization method were prepared. The composition of the iron alloy powder is 2 mass% Ni-0.5 mass% Mo-balance Fe and inevitable impurities, and the average particle diameter (D50) is 70 μm. The average particle diameter (D50) of the carbon powder is 5 μm. When the raw material powder was 100% by mass, the carbon powder content was 0.3% by mass, and the balance was iron alloy powder. The raw material powder does not contain a lubricant and an organic binder.

[Molding process]
The raw material powder was pressure-molded to produce a cylindrical compact (outer diameter: 75 mm, height: 20 mm). A mold capable of uniaxial pressing was used for the production of the green compact. This mold has openings on the top and bottom and forms a die having circular insertion holes that form the outer peripheral surface of the cylindrical powder compact, and both end faces of the cylindrical compact. And upper and lower punches having a circular press surface. On the inner peripheral surface of the die, an alcohol solution of myristic acid was applied as a lubricant.
The molding pressure is as shown in Table 1. The molding pressure in Table 1 is a numerical value obtained by converting “8 ton / cm ² to 20 ton / cm ² ” into “MPa” and rounding.

The relative density of the produced green compact was measured. The relative density of the green compact was determined from “{(molding density of the green compact) / (true density of the green compact)} × 100”. The compacting density of the compacted body is determined by immersing the compacted body in oil, “oil content density × {(mass of compacted body before oil impregnation) / (mass of compacted compact after oil impregnation)}” I asked for it. The oil impregnation density is a value obtained by dividing the mass of the green compact after oil impregnation by the volume of the green compact. The true density of the green compact (raw material powder) is about 7.8 g / cm ³ . Table 1 shows the molding density and the relative density of the green compact of each sample. Moreover, the relationship between the shaping | molding pressure (MPa) of the compacting body of each sample and a shaping | molding density (g / cm < ³ >) is shown in FIG. The horizontal axis of the graph shown in FIG. 1 is the molding pressure (MPa), and the vertical axis is the molding density (g / cm ³ ). In FIG. 1-1-No. The results of 1-3 are plotted with black circles. 1-101-No. The results of 1-103 are plotted with black diamonds.

[Sintering process]
The green compact was sintered to produce a sintered member. The sintering conditions were a sintering temperature of 1150 ° C., a sintering time of 60 minutes, and a sintering atmosphere of a nitrogen atmosphere.

[Sample No. 1-111-No. 1-117]
Sample No. 1-111-No. The sintered member No. 1-117 has a sample No. 1 except that the lubricant is not applied to the mold and the raw material powder further contains a lubricant. It was produced in the same manner as 1-1. Ethylene bis stearamide was used as the lubricant, and the content of the lubricant in the raw material powder was 0.6% by mass. Sample No. 1-111-No. The relative density of the green compact of 1-117 was measured as Sample No. Measurement was performed in the same manner as in 1-1. Table 1 shows the molding density and the relative density of the green compact of each sample. Moreover, the relationship between the shaping | molding pressure (MPa) of the compacting body of each sample and a shaping | molding density (g / cm < ³ >) is shown in FIG. Sample No. 1-111-No. The results of 1-117 are plotted with white squares.

As shown in Table 1 and FIG. 1-1-No. It can be seen that the relative density of each of the 1-3 compacts is 97% (molding density≈7.57 g / cm ³ ) or more. From this result, sample no. 1-1-No. It is considered that the relative density of each of the 1-3 sintered members exceeds 97% (molding density≈7.57 g / cm ³ ).

In contrast, sample no. 1-101-No. 1-103, no. 1-111-No. It can be seen that the relative density of the green compacts of 1-117 is less than 97%. From this result, sample no. 1-101-No. 1-103, no. 1-111-No. It is considered that the relative density of each of the sintered members 1-117 is less than 97%.

[Evaluation of strength]
The strength of the sintered member was evaluated by performing a tensile test and measuring the tensile strength. Sample No. In the same manner as in 1-1, the sample No. Cylindrical sintered members of 2-1, 2-2, 2-101 to 2-103 were produced. Here, the molding pressure was adjusted so that the molding density (relative density) of each sample was the value shown in Table 2. This cylindrical sintered member was processed into a predetermined shape and subjected to carburizing and quenching to prepare a test piece for measuring tensile strength. A test piece is flat form comprised by the narrow part and the wide part formed in the both ends of a narrow part. The thickness of the test piece is 4 mm and the length is 72 mm. The narrow width portion is composed of a central portion and a shoulder portion having an arcuate side surface formed from the central portion to the wide width portion. The central portion has a length of 32 mm, the central width is 5.7 mm, and both ends have a width of 5.96 mm. The radius R of the side surface of the shoulder is 25 mm. The width of the thick part is 8.7 mm.
A tensile test was performed on the test piece using a general-purpose tensile tester.

The results of tensile strength (MPa) are shown in Table 2. The tensile strength (MPa) shown in Table 2 is an average value of the evaluation number n = 5. FIG. 2 shows the relationship between the molding density (g / cm ³ ) and the tensile strength (MPa). The horizontal axis of the graph shown in FIG. 2 is the molding density, and the vertical axis is the tensile strength. In FIG. 2-1, No. 2 The average value of the tensile strength of 2-2 was plotted with black circles, and sample No. 2-101-No. The average value of the tensile strength of 2-103 is plotted with black diamonds, and the maximum value and the minimum value of the tensile strength in these samples are indicated by error bars.

As shown in Table 2 and FIG. 2-1. It can be seen that the tensile strength of the test piece (sintered member) 2-2 is 1700 MPa or more, further 1750 MPa or more, particularly 1800 MPa or more. In contrast, sample no. 2-101-No. It can be seen that the tensile strength of the 2-103 test piece (sintered member) is less than 1700 MPa. Therefore, it can be understood that a sintered member having a high density and high strength can be obtained by sintering a green compact having a relative density of 97% or more.

Note that a common chromium-molybdenum steel (SCM415) used for structural parts that are extremely loaded such as transmission gears for automobiles is used as a sample No. When the tensile strength was measured in the same manner as in 1-1, the tensile strength was 1372 MPa. That is, sample no. 2-1. It can be seen that the tensile strength of the sintered member 2-2 is very high.

It should be understood that the embodiment disclosed herein is illustrative in all respects and is not restrictive in any way. The scope of the present invention is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.

Claims

Preparing a raw material powder containing iron-based powder;
A step of pressure-molding the raw material powder to form a cylindrical or cylindrical powder compact having a relative density of 97% or more;
A step of sintering the green compact.
The raw material powder includes at least one of a mixed powder containing pure iron powder and Ni powder, and an iron alloy powder containing Ni as an additive element,
The manufacturing method of the sintered member whose total content of the said Ni powder in the said raw material powder and Ni as said additional element is 1 mass% or more.
The method for producing a sintered member according to claim 1, further comprising a step of cutting the green compact after the step of forming and before the step of sintering.