JP5207525B2 - Mold and mold manufacturing method - Google Patents

Description

  The present invention relates to a mold and a method for manufacturing the mold. Specifically, the present invention relates to a mold in which irregularities are formed on the surface in contact with the workpiece and a method for manufacturing the mold.

  In order to protect the environment and prevent global warming, there is an increasing tendency to reduce fossil fuel consumption, and there is a strong demand for reducing the weight of automobile bodies that are indispensable for everyday life as a means of transportation. In order to achieve this weight reduction, it is necessary to reduce the size and weight of automobile parts and ensure the rigidity and strength of the parts. For this reason, the shape of the parts becomes more complicated with the use of a high-strength steel sheet, which causes a situation that cannot be formed by an existing forming method when press forming.

  In addition, as a technique for improving the life of the mold, a steel shot material is projected onto the surface of the mold in order to impart residual compressive stress near the surface of the mold to improve mechanical properties and fatigue life. Shot peening is performed. For example, Patent Document 1 discloses that a shot material is applied to a nitriding member having a nitride dense layer formed on the member and a nitride porous layer formed on the nitride dense layer by nitriding the member. A shot peening method for a nitriding member for projecting and shot peening, comprising a projecting step of projecting a shot material harder than a nitride porous layer at a projection speed of 50 m / sec or more and 200 m / sec or less, and nitriding A method for removing the porous layer is described, and it is also described that a shot material having a particle size of 0.005 mm to 0.08 mm is used as the shot material.

JP 2007-56333 A

  However, when the projection process is a single step as in the conventional shot peening method, when this method is applied to the surface of the mold, the uneven shape of the unevenness formed on the surface of the mold tends to be sharp, In particular, when a fine shot material having a particle size of 0.005 mm or more and 0.08 mm or less, that is, 5 μm or more and 80 μm or less is used, the uneven convex shape formed on the surface of the mold is likely to be sharp. There is a problem that the friction coefficient of the surface of the mold becomes large and seizure occurs with the workpiece. Moreover, since the shot peening method projects the shot material on the nitrided member, the nitride layer is crushed and removed, and there is a possibility that a member having sufficient hardness cannot be obtained. there were.

  The present invention was devised in view of the above points, and provides a mold for suppressing seizure between a workpiece and a mold manufacturing method capable of manufacturing such a mold. With the goal.

  In order to achieve the above object, a mold according to the present invention is a mold in which unevenness is processed and formed on a surface in contact with a workpiece, and the unevenness is a first in which distances between convex portions are different from each other. And the depth of the first uneven area is substantially the same as the depth of the second uneven area, and the depth from the surface is about 5 μm. It is a work-hardened layer, and a nitride layer extends from the surface to a depth of 20 to 80 μm.

Here, the unevenness on the mold surface is composed of the first unevenness region and the second unevenness region where the distance between the protrusions is different from each other, so that there are fine unevenness regions that are formed and processed and hardened. In addition, it becomes difficult to be crushed by the workpiece, and there are a large number of recesses in which the lubricating oil is held, so that the slidability is improved.
In addition, since the depth of the first uneven area and the depth of the second uneven area are substantially the same, the recesses in which the lubricating oil is held can be evenly secured, and the slidability is improved.

  In order to achieve the above object, the mold manufacturing method of the present invention is a mold manufacturing method for manufacturing a mold in which irregularities are formed on the surface in contact with the workpiece, The surface that contacts the object is processed, and is composed of a first uneven region and a second uneven region in which the distance between the convex portions is different from each other, and the depth of the first uneven region and the second uneven surface. Concavity and convexity forming step for forming concavities and convexities having substantially the same depth in the region on the surface in contact with the workpiece, and a nitriding treatment step for forming a nitrided layer by nitriding the concavities and convexities formed by the concavity and convexity forming step It is characterized by having.

Here, the surface in contact with the workpiece is processed, and the first uneven region and the second uneven region having different distances between the protrusions are formed. The unevenness area formed by the unevenness forming process for forming the unevenness having substantially the same depth of the unevenness area 2 on the surface in contact with the work piece is finely formed and is crushed by the work piece. There are a large number of recesses in which the lubricating oil is held and the recesses in which the lubricating oil is held can be ensured uniformly, and a mold with improved slidability can be manufactured.
In addition, by nitriding the unevenness formed in the unevenness forming process, dislocations are introduced into the unevenness by being processed, so that nitrogen can easily enter the mold even at a relatively low temperature, and harden into the mold. Become.
In the present invention, the concavo-convex process forming step and the nitriding step are steps performed on a mold molded using a mold material.

  Moreover, in the manufacturing method of the metal mold | die of this invention, an uneven | corrugated process formation process is a 1st projection process which projects 1st particle | grains on the surface which contacts a workpiece, and a 1st projection process, after a 1st projection process, In the case of the second projecting step of projecting the second particle having a particle size smaller than the particle on the surface in contact with the workpiece, the second projecting step is performed on the convex portion formed in the first projecting step. Since the second particles projected by the collision collide to form irregularities, the concave portions in which the lubricating oil is held can be formed uniformly.

  Further, in the mold manufacturing method of the present invention, when the nitriding process is performed in a nitrogen gas-containing atmosphere at 300 to 460 ° C., the nitriding process is performed at a relatively low temperature, so that thermal distortion of the mold can be suppressed. Here, if it is less than 300 ° C., a sufficient nitride layer may not be obtained, and if it exceeds 460 ° C., thermal distortion may be a problem.

  In the mold manufacturing method of the present invention, when the particle size of the first particles is 150 μm or more, the work-cured region can be formed in a wide range with a small number of particles. Here, when it is less than 150 μm, it is considered that there is not sufficient unevenness forming ability.

  The metal mold | die which concerns on this invention can suppress the seizure between workpieces.

  With the mold manufacturing method according to the present invention, a mold capable of suppressing seizure between the workpiece and the workpiece can be manufactured.

Hereinafter, embodiments of the present invention will be described with reference to the drawings to facilitate understanding of the present invention.
FIG. 1 is a schematic diagram for explaining how the surface of a mold is processed to obtain a mold to which the present invention is applied. First, first particles having a particle size of 100 to 500 μm, for example, alumina particles and stainless steel particles are projected onto a mold surface 1 with which a workpiece comes into contact at a projection pressure of 0.20 to 0.35 MPa. As shown to (a), the 1st uneven | corrugated area | region 2 which has the depth H1 is formed (1st projection process).
Next, second particles having a particle diameter smaller than the first particles, such as alumina particles and stainless steel particles, are projected onto the mold surface 1 on which the workpiece is in contact, in which the first uneven region 2 is formed. By projecting at a pressure of 0.20 to 0.35 MPa, as shown in FIG. 1B, a second uneven region 3 having a depth H2 is formed (second projecting step). Here, the depth H1 ′ and the depth H2 which are changed from the depth H1 due to the collision of the particles are substantially the same, but the distance between the convex portions of the first concave-convex region 2 is the same as that of the second concave-convex region 3. It is longer than the distance between the convex parts.

In addition, the second uneven region 3 is formed on the convex portion of the first uneven region 2 because the concave portion of the first uneven region 2 is work-hardened by collision with the first particles. The second particles are unlikely to be deformed even when they collide with the recesses. On the other hand, it is considered that the projections are relatively soft because they are not sufficiently work-hardened, and the second particles collide with each other to easily form dents.
In FIG. 1, only one first concavo-convex area and two second concavo-convex areas are shown for easy understanding, but the first concavo-convex area referred to in the present invention is defined between the convex parts. It is a set of various uneven areas with different distances, and the distance between the shortest protrusions is the set of various uneven areas with the same distance between the protrusions. An area longer than the distance.

By such a two-stage projection process, the metal constituting the mold is distorted, the hardness is increased by plastic deformation, and the work hardened layer 4 is formed from the mold surface 1 to a depth of about 5 μm.
Next, the mold in which the first concavo-convex region 2 and the second concavo-convex region 3 are formed on the surface by the first projecting step and the second projecting step is ammonia gas and nitrogen at a temperature of 300 to 460 ° C. Nitrided by exposure to a gas atmosphere or nitrogen gas atmosphere to form a nitrided layer 5 from the mold surface to a depth of 20 to 80 μm as shown in FIG. 1C, and the work hardened layer is nitrided The work hardening layer 4A thus obtained is obtained. It is sufficient that the depth of the nitride layer is up to 80 μm. If an attempt is made to form the nitride layer deeper than this, an economic burden arises.
Moreover, as a material which comprises a metal mold | die, ductile cast iron (FCD450) and die steel (SKD11) can be used.

  Hereinafter, the present invention will be described in more detail based on examples. The die steel (SKD11) used here constitutes the surface of the mold that actually contacts the workpiece.

<Example 1>
After projecting alumina particles having a particle size of 200 μm (0.2 mm) onto a die steel (SKD11) at a projection pressure of 0.25 MPa, stainless steel (SUS304) particles having a particle size of 100 μm (0.1 mm) are projected at a projection pressure of 0. Projected at 35 MPa. Then, the die steel (SKD11) on which the particles are projected is embedded in the filled granular solid, a nitriding gas is circulated in the granular solid, and the nitriding gas is once adsorbed on the surface of the granular solid. Nitrogen treatment was performed by bringing atomic nitrogen into continuous contact under heating at 460 ° C, for example, at 380-520 ° C.
Moreover, the graph which carried out the Fourier transformation of the surface shape of the die steel (SKD11) obtained through the two-step projection process and nitriding treatment in Example 1 is shown in FIG. In FIG. 3, the horizontal axis indicates the frequency, and the vertical axis indicates the spectrum amplitude (the depth of the unevenness). Here, a region on the right side of the center of the horizontal axis is a high frequency region, that is, a second uneven region, and a region on the left side of the center of the horizontal axis is a low frequency region, that is, a first uneven region.
Moreover, the figure which shows the surface roughness of the die steel (SKD11) obtained through the two-step projection process and nitriding process in Example 1 in FIG. 4 is shown.
Next, using the die steel (SKD11) obtained through the two-stage projection process and the nitriding treatment as described above, a sliding test was performed as shown in FIG. That is, while pressing the sample 6 against the cold-rolled steel plate (SPFC440) 9 in the pressing direction 7 while increasing the pressing load by 200 kg, the cold-rolled steel plate 9 is pulled out in the drawing direction 8 at a speed of 1 m / min. The load (galling resistance) seized on the cold rolled steel sheet 9 was examined. The results are shown in Table 1.

<Example 2>
A stainless steel (SUS304) particle having a particle size of 100 μm (0.1 mm) is applied to a die steel (SKD11) after projecting a stainless steel (SUS304) particle having a particle size of 500 μm (0.5 mm) at a projection pressure of 0.35 MPa. Was projected at a projection pressure of 0.35 MPa. Then, the die steel (SKD11) on which the particles are projected is embedded in the filled granular solid, a nitriding gas is circulated in the granular solid, and the nitriding gas is once adsorbed on the surface of the granular solid. Nitriding was carried out by continuously contacting atomic nitrogen under heating at 460 ° C.
FIG. 5 shows a graph obtained by Fourier transforming the surface shape of the die steel (SKD11) obtained through the two-stage projection process and nitriding treatment in Example 2. Moreover, the figure which shows the surface roughness of the die steel (SKD11) obtained through the two-step projection process and nitriding process in Example 2 in FIG. 6 is shown.
Next, a sliding test was performed in the same manner as in Example 1 using the die steel (SKD11) obtained through the two-stage projection process and the nitriding treatment as described above. The results are shown in Table 1.

<Example 3>
A stainless steel (SUS304) particle having a particle size of 100 μm (0.1 mm) is applied to a die steel (SKD11) after projecting a stainless steel (SUS304) particle having a particle size of 200 μm (0.2 mm) at a projection pressure of 0.35 MPa. Was projected at a projection pressure of 0.35 MPa. Then, the die steel (SKD11) on which the particles are projected is embedded in the filled granular solid, a nitriding gas is circulated in the granular solid, and the nitriding gas is once adsorbed on the surface of the granular solid. Nitriding was carried out by continuously contacting atomic nitrogen under heating at 460 ° C.
Moreover, the graph which carried out the Fourier transformation of the surface shape of the die steel (SKD11) obtained through the two-step projection process and nitriding treatment in Example 3 is shown in FIG. Moreover, the figure which shows the surface roughness of the die steel (SKD11) obtained through the two-step projection process and nitriding process in Example 3 in FIG. 8 is shown.
Next, a sliding test was performed in the same manner as in Example 1 using the die steel (SKD11) obtained through the two-stage projection process and the nitriding treatment as described above. The results are shown in Table 1.

<Example 4>
After projecting alumina (alundum) particles having a particle size of 300 μm (0.3 mm) on a die steel (SKD11) at a projection pressure of 0.2 MPa, amorphous alloy particles having a particle size of 50 μm (0.05 mm) (Amo beads ( (Registered trademark)) was projected at a projection pressure of 0.2 MPa. Then, the die steel (SKD11) on which the particles are projected is embedded in the filled granular solid, a nitriding gas is circulated in the granular solid, and the nitriding gas is once adsorbed on the surface of the granular solid. Nitriding was carried out by continuously contacting atomic nitrogen under heating at 460 ° C.
Next, a sliding test was performed in the same manner as in Example 1 using the die steel (SKD11) obtained through the two-stage projection process and the nitriding treatment as described above. The results are shown in Table 1.

<Example 5>
After projecting alumina (alundum) particles having a particle size of 300 μm (0.3 mm) on a die steel (SKD11) at a projection pressure of 0.2 MPa, zirconia particles having a particle size of 50 μm (0.05 mm) are projected at a projection pressure of 0. Projected at 2 MPa. Then, the die steel (SKD11) on which the particles are projected is embedded in the filled granular solid, a nitriding gas is circulated in the granular solid, and the nitriding gas is once adsorbed on the surface of the granular solid. Nitriding was carried out by continuously contacting atomic nitrogen under heating at 460 ° C.
Next, a sliding test was performed in the same manner as in Example 1 using the die steel (SKD11) obtained through the two-stage projection process and the nitriding treatment as described above. The results are shown in Table 1.

<Comparative Example 1>
Stainless steel (SUS304) particles having a particle size of 100 μm (0.1 mm) were projected at a projection pressure of 0.35 MPa on die steel (SKD11). The die steel (SKD11) on which the particles were projected was subjected to nitriding treatment by exposure to an atmosphere of ammonia gas and nitrogen gas at 460 ° C.
Next, a sliding test was conducted in the same manner as in Example 1 using the die steel (SKD11) obtained through the one-step projection process and nitriding as described above. The results are shown in Table 1.

<Comparative example 2>
Alumina particles having a particle size of 200 μm (0.2 mm) were projected onto a die steel (SKD11) at a projection pressure of 0.35 MPa. The die steel (SKD11) on which the particles were projected was subjected to nitriding treatment by exposure to an atmosphere of ammonia gas and nitrogen gas at 460 ° C.
Next, a sliding test was conducted in the same manner as in Example 1 using the die steel (SKD11) obtained through the one-step projection process and nitriding as described above. The results are shown in Table 1.

<Comparative Example 3>
To die steel (SKD11), alumina (alundum) particles having a particle size of 300 μm (0.3 mm) were projected at a projection pressure of 0.2 MPa. The die steel (SKD11) on which the particles were projected was subjected to nitriding treatment by exposure to an atmosphere of ammonia gas and nitrogen gas at 460 ° C.
Next, a sliding test was conducted in the same manner as in Example 1 using the die steel (SKD11) obtained through the one-step projection process and nitriding as described above. The results are shown in Table 1.

<Comparative example 4>
Alumina particles having a particle size of 500 μm (0.5 mm) were projected onto a die steel (SKD11) at a projection pressure of 0.35 MPa. The die steel (SKD11) on which the particles were projected was subjected to nitriding treatment by exposure to an atmosphere of ammonia gas and nitrogen gas at 460 ° C.
Next, a sliding test was conducted in the same manner as in Example 1 using the die steel (SKD11) obtained through the one-step projection process and nitriding as described above. The results are shown in Table 1.

FIG. 9 is a graph obtained by Fourier transforming the surface shape of ductile cast iron (FCD450) obtained through nitriding after metal particles (SS20) having a particle size of 100 μm (0.1 mm) are projected in one stage. FIG. 10 is a diagram showing the surface roughness of this ductile cast iron (FCD450).
FIG. 11 shows a graph obtained by Fourier transforming the surface shape of ductile cast iron (FCD450) obtained by nitriding after amorphous particles having a particle size of 200 μm (0.2 mm) are projected in one stage. 12 shows a diagram showing the surface roughness of this ductile cast iron (FCD450).
FIG. 13 is a graph obtained by performing Fourier transform on the surface shape of ductile cast iron (FCD450) obtained by nitriding after a stainless steel (SUS304) particle having a particle size of 100 μm (0.1 mm) is projected in one stage. FIG. 14 is a diagram showing the surface roughness of this ductile cast iron (FCD450).

As apparent from FIGS. 3, 5 and 7, as in Examples 1 to 3, after the particles are projected, a two-stage projecting process in which particles having a smaller particle size are projected is performed, followed by nitriding. The surface of the processed mold has substantially the same spectral amplitude, that is, the depth of the unevenness, in the first unevenness region and the second unevenness region in which almost all the frequency bands, that is, the distance between the protrusions are different from each other. there were.
Further, when the mold materials obtained in Examples 1 to 3 were viewed with an SEM (scanning electron microscope), a work hardened layer was formed from the surface of the mold to a depth of about 5 μm. The nitride layer was up to a depth of ˜80 μm.
Further, as apparent from FIGS. 4, 6 and 8, as in Examples 1 to 3, after the particles were projected, after a two-stage projecting process in which particles with a smaller particle size were projected, The surface of the mold subjected to the nitriding treatment is not rough compared to the surface of the mold obtained through the one-step projection process and the nitriding treatment as shown in FIG. 10, FIG. 12 and FIG. It was flat. That is, the surface of the mold obtained through the one-step projection process and nitriding treatment as shown in FIGS. In the two uneven regions, the depth of the unevenness was different from each other.

Further, as apparent from the sliding test results of Examples 1 to 5 and Comparative Examples 1 to 4 shown in Table 1, after the particles are projected, a two-stage projecting process in which particles having a smaller particle size are projected. The mold subjected to nitriding treatment was subjected to a projecting process in which particles were projected in one stage, and exhibited a larger galling resistance than the mold subjected to nitriding treatment. Thereby, it turned out that the metal mold | die of this invention is hard to produce seizure compared with the conventional metal mold | die.
In addition, from this, the first uneven region and the second uneven region having different distances between the protrusions were obtained through a one-step projection process and a nitriding process having surfaces with different uneven depths. The mold is considered to exhibit a galling resistance smaller than that of the mold subjected to the nitriding treatment after passing through a two-stage projecting process in which particles having a smaller particle diameter are projected after the particles are projected, Therefore, it is considered that seizure is likely to occur.
FIG. 15 is a graph showing the relationship between the galling resistance and the first projected particle size for Examples 1 to 5 and Comparative Examples 1 to 4. In FIG. 15, “◯” indicates each example (two-stage projection + nitriding process), and “□” indicates each comparative example (one-stage projection + nitriding process).

  Moreover, although the example which projects a particle | grain on a metal mold | die was demonstrated as a means to process and form an unevenness | corrugation, the surface which contacts a to-be-processed object is processed, and the 1st uneven | corrugated area | region where the distance between convex parts differs from the 1st If the surface is formed of two uneven regions and the unevenness in which the depth of the first uneven region and the depth of the second uneven region are substantially the same as each other can be formed on the surface in contact with the workpiece, the particles May not be projected, may be mechanically processed, and when projecting particles, it may not necessarily be a two-stage projection process, and may be a three-stage or more projection process .

Thus, in the present invention, after the first projecting step of projecting the first particles onto the surface in contact with the workpiece and the first projecting step, the second particle size is smaller than the first particles. A second projecting step of projecting the particles on the surface in contact with the workpiece, the surface in contact with the workpiece is processed, and the first uneven region and the second in which the distance between the convex portions is different from each other Consists of concavo-convex areas, and the first concavo-convex area and the second concavo-convex area have substantially the same concavo-convex depth on the surface in contact with the workpiece. The concave and convex regions are made to exist finely, are not easily crushed by the work piece, and there are many concave portions where the lubricating oil is retained, and the concave portions where the lubricating oil is retained can be secured evenly, improving the slidability. Dies can be manufactured, and processed irregularities are nitrided Therefore, dislocations are introduced into the irregularities after being processed, and nitrogen becomes easy to enter the mold even at a relatively low temperature (pipe diffusion), and hardens to the inside of the mold. It is possible to manufacture a mold that reduces wear and reduces frictional heat and suppresses seizure.
Since the 2nd particle projected by the 2nd projection process collides with the convex part formed at the 1st projection process, and forms unevenness, the concave part where lubricating oil is held can be formed uniformly.

  Further, since the nitriding process is performed in an atmosphere containing nitrogen gas at 300 to 460 ° C., the nitriding process can be performed at a relatively low temperature, and thermal distortion of the mold can be suppressed.

  Moreover, since the particle diameter of the first particles is 150 μm or more, the work-cured region can be formed in a wide range with a small number of particles.

It is the schematic explaining a mode that the surface of a metal mold | die is processed and the metal mold | die which applied this invention is obtained. It is the schematic explaining the outline of a sliding test. It is the graph which carried out the Fourier transformation of the surface shape of the die steel (SKD11) obtained through the two-step projection process in Example 1, and nitriding treatment. It is a figure which shows the surface roughness of the die steel (SKD11) obtained through the two-step projection process and nitriding treatment in Example 1. It is the graph which carried out the Fourier transformation of the surface shape of the die steel (SKD11) obtained through the two-step projection process in Example 2, and nitriding treatment. It is a figure which shows the surface roughness of the die steel (SKD11) obtained through the two-step projection process and nitriding treatment in Example 2. It is the graph which carried out the Fourier transformation of the surface shape of the die steel (SKD11) obtained through the two-step projection process in Example 3, and nitriding treatment. It is a figure which shows the surface roughness of the die steel (SKD11) obtained through the two-step projection process and nitriding treatment in Example 3. It is the graph which carried out the Fourier-transform of the surface shape of the ductile cast iron (FCD450) obtained through the nitriding process after the metal particle (SS20) with a particle size of 100 micrometers (0.1mm) was projected in one step. It is a figure which shows the surface roughness of the ductile cast iron (FCD450) of FIG. It is the graph which carried out the Fourier-transform of the surface shape of the ductile cast iron (FCD450) obtained through the nitriding process after the amorphous particle of a particle size of 200 micrometers (0.2 mm) was projected in one step. It is a figure which shows the surface roughness of the ductile cast iron (FCD450) of FIG. It is the graph which carried out the Fourier transform of the surface shape of the ductile cast iron (FCD450) obtained through the nitriding process after the stainless steel (SUS304) particle | grains with a particle size of 100 micrometers (0.1mm) were projected in one step. It is a figure which shows the surface roughness of the ductile cast iron (FCD450) of FIG. It is a graph which shows the relationship between the galling-proof load about Examples 1-5 and Comparative Examples 1-4 and the 1st projection particle size.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold surface 2 1st uneven | corrugated area | region 3 2nd uneven | corrugated area | region 4 Work hardening layer 4A Nitrided work hardening layer 5 Nitride layer 6 Sample 7 Pushing direction 8 Pull-out direction 9 Cold-rolled steel plate

Claims (5)

A mold in which irregularities are processed and formed on the surface in contact with the workpiece,
The concavo-convex is composed of a first concavo-convex area and a second concavo-convex area where the distance between the ridges is different from each other, and the depth of the first concavo-convex area is the same as the depth of the second concavo-convex area. Almost the same,
The second concavo-convex region is formed on a convex portion of the first concavo-convex region,
Up to a depth of about 5 μm from the surface is a work hardened layer,
A mold from the surface to a depth of 20 to 80 μm is a nitride layer. A mold manufacturing method for manufacturing a mold in which irregularities are formed on a surface in contact with a workpiece,
The surface that contacts the workpiece is processed, and is composed of a first concavo-convex area and a second concavo-convex area in which the distance between the convex portions is different from each other, and the depth of the first concavo-convex area is the same as the second. Concavity and convexity forming that forms the concavities and convexities in which the depths of the concavity and convexity regions are substantially the same with each other and the second concavity and convexity are formed on the convex portions of the first concavity and convexity regions on the surface that contacts the workpiece Process,
And a nitriding treatment step of forming a nitride layer by nitriding the irregularities formed in the irregularity forming step. The concavo-convex process forming step includes a first projecting step of projecting the first particles onto the surface in contact with the workpiece,
The second projecting step of projecting, after the first projecting step, second particles having a smaller particle size than the first particles onto a surface in contact with the workpiece. The manufacturing method of the metal mold | die as described in. The said nitriding process process is performed in 300-460 degreeC nitrogen gas containing atmosphere. The manufacturing method of the metal mold | die of Claim 2 characterized by the above-mentioned. The method for producing a mold according to claim 3, wherein the particle diameter of the first particles is 150 µm or more.

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