Coated mold

Abstract

The coated mold has a mold and a hard coating film formed on at least a part of the outer surface of the mold. The hard coating film contains a nitride, carbonitride, oxide, or oxynitride of a metal element; the content of Al is 65 at% or more, the content of Cr is 15 at% or more, and the total content of Al and Cr is 80 at% or more and 100 at% or less, based on the total amount of the metal elements contained in the hard coating film; the surface roughness Ra of the hard coating film is 0.05 [mu] m or less; the d value of the hard coating film due to the (111) plane of the face-centered cubic lattice is from 2.25 to 2.45 (inclusive).

Description

Technical Field

[0001] This invention relates to a coated mold having a mold and a rigid film. Background Technology

[0002] In dies such as punches used in forging and pressure processing, not only hardness but also wear resistance is required to extend the service life of the die. To improve the wear resistance of the die, a hard film composed of nitrides or carbonitrides such as AlCr and AlCrSi is coated onto the die using methods such as physical vapor deposition or chemical vapor deposition, while simultaneously treating the hard film to impart good surface smoothness.

[0003] For example, Patent Document 1 describes a coated mold for plastic processing, characterized in that a hard film composed of AlxCrySiz nitride is coated on the surface of the mold substrate. Specifically, the coated mold for plastic processing described in Patent Document 1 includes a technique for improving the wear resistance of the coated mold by forming a hard film that is as smooth as possible on the working surface of the mold using a sputtering method.

[0004] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2010-284710. Summary of the Invention

[0005] The purpose of this invention is to provide a coating mold with excellent durability.

[0006] The inventors conducted dedicated research to solve the aforementioned problems, resulting in this invention.

[0007] That is, the coating mold of the present invention has a mold and a hard film formed on at least a portion of the outer surface of the mold; the hard film contains nitrides, carbonitrides, oxides or oxynitrides of metallic elements; in the total amount of the aforementioned metallic elements contained in the hard film, the Al content is 65 atomic% or more, the Cr content is 15 atomic% or more, and the total content of Al and Cr is 80 atomic% or more and 100 atomic% or less; the surface roughness Ra of the hard film is 0.05 μm or less; the d value of the (111) plane of the face-centered cubic lattice of the hard film is 2.25 Å or more and 2.45 Å or less. Attached Figure Description

[0008] Figure 1 This is a schematic top view used to illustrate the shape of the punch in the embodiment.

[0009] Figure 2 yes Figure 1 An enlarged view of part E in the image.

[0010] Figure 3 This is a cross-sectional view of the observation area of ​​the coated punch after the cold forging test in the embodiment.

[0011] Figure 4 It is a cross-sectional image of the observation plane of the coated punch at various angles after the cold forging test in Example 1.

[0012] Figure 5 It is a cross-sectional image of the observation plane of the coated punch at various angles after the cold forging test in Example 2.

[0013] Figure 6 It is a cross-sectional image of the observation plane of the coated punch at various angles after the cold forging test in Example 3.

[0014] Figure 7 It is a cross-sectional image of the observation plane of the coated punch at various angles after the cold forging test in Comparative Example 1.

[0015] Figure 8 This is a cross-sectional image of the observation plane of the coated punch at various angles after the cold forging test in Comparative Example 2. Detailed Implementation

[0016] If a hard coating is formed by sputtering as described in Patent Document 1, there is a possibility that the coating material, which was not ionized during film formation, reaches the mold surface as a substrate. This results in poor adhesion between the coated mold and the hard coating. If the coated mold with poor adhesion is used under high-load processing conditions, such as cold forging, even if the hard coating has good surface smoothness, durability (i.e., mold life) is problematic. Therefore, further improvements in durability are required in coated molds with hard coatings.

[0017] The inventors have conducted dedicated research and found that, in a coated mold having a mold and a hard film formed on at least a portion of the outer surface of the mold, a coated mold with excellent durability can be obtained when the hard film has a predetermined composition, a surface roughness Ra below a predetermined value, and a predetermined d value (i.e., the interplanar spacing value) of the (111) plane of the face-centered cubic lattice.

[0018] The following is a reference to the appendix. Figure 1 The embodiments of the present invention will be described in detail below. Furthermore, the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without prejudice to the spirit of the invention.

[0019] 1. Structure of the coating mold First, the structure of the coating mold in this embodiment will be described. The coating mold has a mold and a hard film formed on at least a portion of the outer surface of the mold. In this specification, "outer surface of the mold" refers to the surface portion (i.e., functional portion) of the mold that comes into contact with the workpiece during use. In other words, the hard film only needs to be formed on at least a portion of the functional portion of such a mold. Hereinafter, these constituent elements will be described in detail.

[0020] 1-1. Mold The type and shape of the mold are not particularly limited. For example, molds can include extrusion molding molds, upsetting molds, blanking molds, stamping molds, and various pressure forming molds. In addition, the material of the mold is not particularly limited. For example, iron-based alloys (e.g., SKD (Steel KoguDice) material, SKS (Steel Kogu Special) material), high-speed tool steel (e.g., HSS (High Speed ​​Steel)), superhard alloys, and various ceramics.

[0021] Specifically, the mold is not particularly limited, but a punch used to plastically shape the workpiece by colliding with it is preferred. The type of punch is not particularly limited; examples include punches with cross-sectional shapes such as quadrilaterals, hexagons, ellipses, and gears, and punches with shapes corresponding to the inner diameter of the forged workpiece. For example, a punch with a hexagonal cross-sectional shape can be used as a punch for forming bolts, nuts, etc. In addition, in this specification, the mold may also include, for example, a jig for plastic forming such as a puncher or pin, or a die used in combination with a punch, puncher, pin, etc.

[0022] Especially from the viewpoint of requiring high durability, dies are preferably used for cold plastic forming. Furthermore, among dies for cold plastic forming, from the viewpoint of use in particularly harsh environments, dies for cold forging are preferred. Specifically, in cold forging dies, tensile and compressive stresses are repeatedly applied in a closed region at high speeds (e.g., more than 50 times per minute). Therefore, compared to other dies that can be used for multiple purposes, cold forging dies require higher durability against repeated stresses. By forming the hardened film described later in such cold forging dies, the durability of the die can be improved more effectively, and the die life can be extended.

[0023] 1-2. Hard membrane In this embodiment, a hard film is formed on at least a portion of the outer surface of the aforementioned mold, for example by a method described later. Furthermore, the hard film has a predetermined composition, a surface roughness Ra below a predetermined value, and a predetermined d value originating from the (111) plane of a face-centered cubic lattice. This will be explained in detail below.

[0024] <Composition of Hard Skin> The hard coating comprises nitrides, carbonitrides, oxides, or oxynitrides of metallic elements. Furthermore, in the total amount of metallic elements contained in the hard coating, the Al content is 65 atomic% or more, the Cr content is 15 atomic% or more, and the combined content of Al and Cr is 80 atomic% or more and 100 atomic% or less. In this specification, "metallic element" refers not only to metallic elements but also to any partially metallic elements that are present.

[0025] In this specification, the composition of the total amount of metal elements contained in such a hard coating with Al content, Cr content, etc., refers to the average composition of the metal elements contained in the hard coating. The average composition of the metal elements contained in the hard coating, as described in detail in the following examples, can be measured, for example, by analysis using an energy dispersive X-ray spectrometer (EDS).

[0026] (Al and Cr) Nitrides, carbonitrides, oxides, or oxynitrides, primarily composed of Al and Cr, are excellent film types that balance wear resistance and heat resistance, and also exhibit superior adhesion to molds. In particular, by increasing the Al content in nitrides, carbonitrides, oxides, or oxynitrides, an oxide protective film is easily formed on the surface of the hard film, inhibiting oxidative wear. Simultaneously, increasing the Al content leads to a finer microstructure in the hard film, resulting in increased film hardness.

[0027] Specifically, the microstructural refinement of a hard coating refers to an increase in the number of grain boundaries within the coating. During coating crystallization, there are defects—point defects, line defects, or surface defects—in their atomic arrangement. When external stress is applied to the hard coating during mold use, these defects can move, resulting in coating damage. On the other hand, grain boundaries prevent the movement of these defects. Therefore, if the proportion of grain boundaries increases through crystal refinement, dislocation movement is suppressed, thereby increasing the strength of the hard coating.

[0028] Thus, by increasing the Al content ratio, oxidative wear of the hard film is suppressed, frictional wear of the film is suppressed by the increased hardness of the film due to the micronization of the hard film structure, and the strength of the film under external stress environment is improved.

[0029] In the rigid coating of this embodiment, the Al content is 65 atomic% or more of the total amount of metal elements contained in the rigid coating. If the Al content is 65 atomic% or more, the aforementioned Al addition effect can be fully utilized. Preferably, the Al content is 67 atomic% or more, more preferably 68 atomic% or more, and even more preferably a value selected from the group consisting of 70 atomic%, 72 atomic%, 74 atomic%, and 75 atomic%.

[0030] On the other hand, if the Al content is too high, the hardness of the hard coating may decrease. Therefore, the Al content in the total amount of metal elements contained in the hard coating is preferably 80 atomic% or less. Furthermore, the Al content in the total amount of metal elements contained in the hard coating is more preferably 78 atomic% or less, and even more preferably 77 atomic% or less.

[0031] In the hard coating of this embodiment, the Cr content is 15 atomic% or more in the total amount of metal elements contained in the hard coating. If the Cr content is 15 atomic% or more, a uniform and dense oxide protective film is easily formed on the surface of the hard coating formed on the coating mold in this embodiment, and damage to the hard coating is easily suppressed. The Cr content in the total amount of metal elements contained in the hard coating is preferably 18 atomic% or more, more preferably 20 atomic% or more, and even more preferably a value selected from the group consisting of 22 atomic%, 23 atomic%, 25 atomic%, and 28 atomic%.

[0032] On the other hand, if the Cr content is too high, it is difficult to obtain the aforementioned effects brought about by increasing the Al content. Therefore, in the total amount of metal elements contained in the hard coating, the Cr content is 35 atomic% or less, preferably 34 atomic% or less, more preferably 32 atomic% or less, and even more preferably 30 atomic% or less.

[0033] In the rigid coating of this embodiment, the total content of Al and Cr in the total amount of metal elements contained in the rigid coating is 80 atomic% to 100 atomic%. If the total content of Al and Cr is 80 atomic% to 100 atomic%, excellent durability can be imparted to the coated mold. The total content of Al and Cr is preferably 85 atomic% or more, more preferably 87 atomic% or more, further preferably a value selected from the group consisting of 90 atomic%, 93 atomic%, 96 atomic%, and 99 atomic%, and particularly preferably 100 atomic%.

[0034] Rigid coatings include nitrides, carbonitrides, oxides, or oxynitrides of the aforementioned metallic elements. From the viewpoint of having superior heat resistance, rigid coatings are preferably nitrides of metallic elements.

[0035] Specifically, as an example of such a hard coating, the hard coating is composed of nitrides of metal elements. Preferably, in the total amount of metal elements contained in the hard coating, the Al content is 65 atomic% to 80 atomic% and the Cr content is 20 atomic% to 35 atomic%, and the total content of Al and Cr is 100 atoms.

[0036] (Metallic elements other than Al and Cr) Hard coatings can also contain metallic elements other than Al and Cr within a range that does not significantly reduce the durability of the coated mold.

[0037] For example, hard coatings, aimed at improving properties such as wear resistance, heat resistance, and durability (hereinafter also referred to as "coating properties"), may contain one or more metallic elements selected from groups 4a, 5a, and 6a of the periodic table (groups 4, 5, and 6 in long-period periodic tables) and the group consisting of Si, B, Y, Yb, and Cu. Si and B among these elements are examples of half-metals. These elements are generally included to improve the coating properties of hard coatings.

[0038] If the content of metal elements other than Al and Cr becomes too high, the durability of the coated parts may decrease. Therefore, when the hard coating contains metal elements other than Al and Cr, the total content of these metal elements is preferably 20 atomic% or less, more preferably 10 atomic% or less, even more preferably 5 atomic% or less, and particularly preferably 3 atomic% or less, out of the total amount of metal elements contained in the hard coating.

[0039] <Surface roughness Ra (arithmetic mean height) of the hard coating> In this embodiment, the surface roughness Ra of the hard film is 0.05 μm or less. In this specification, "surface roughness Ra of the hard film," as detailed in the later embodiments, refers to the arithmetic mean height Ra measured using a surface roughness measuring machine according to JIS-B-0601 (2001). More specifically, in this specification, "surface roughness Ra of the hard film" refers to the surface roughness Ra of the hard film after grinding (post-processing) following the formation of the hard film; and refers to the surface roughness Ra of the hard film immediately after its formation if no grinding (post-processing) is performed.

[0040] If the surface roughness Ra of the rigid film is less than 0.05 μm, the rigid film has good surface smoothness, resulting in a coated mold with excellent durability. Preferably, the surface roughness Ra of the rigid film is less than 0.04 μm, and more preferably less than 0.03 μm.

[0041] The surface roughness Ra of a hard film can be easily set to a low value of 0.05 μm or less, for example, by forming a hard film using an arc ion plating method with a film-forming apparatus equipped with a permanent magnet, a filtering mechanism, etc., as described later. Even without post-treatment for surface smoothing such as grinding after the hard film is formed, this method can be very effective. Specifically, by forming a hard film using such an arc ion plating method, the adhesion of large particles (droplets) to the mold during film formation is reduced, resulting in a hard film with significantly superior surface smoothness. As a result, a coated mold with excellent durability can be obtained.

[0042] <The hard coating originates from the d-value of the (111) plane of the face-centered cubic lattice> In this embodiment, the rigid coating is formed by a d-value (hereinafter also simply referred to as the "d-value of the rigid coating") of the (111) face-centered cubic lattice, which is between 2.25 Å and 2.45 Å. When the d-value of the rigid coating is less than 2.25 Å, the stress in the coating is too high, making it easy for the coating to peel off from the substrate. When the d-value of the rigid coating is greater than 2.45 Å, the stress in the coating is too low, resulting in a shorter coating lifespan. Therefore, the d-value of the rigid coating is preferably set to between 2.25 Å and 2.45 Å. As a result, a coated mold with excellent durability can be obtained.

[0043] The d-value of the rigid coating is preferably 2.30 Å or more, more preferably 2.35 Å or more. Furthermore, the d-value of the rigid coating is preferably 2.43 Å or less, more preferably less than 2.40 Å, further preferably 2.39 Å or less, and particularly preferably 2.38 Å or less.

[0044] In this specification, “the hard coating originates from the d-value of the (111) face of the face-centered cubic lattice” refers to the value obtained by means of the method described in detail in the following examples.

[0045] Specifically, the d-value of the (111) plane of the face-centered cubic lattice, which is the origin of the hard film, can be determined by using an X-ray analysis apparatus, identifying the crystal structure of the hard film, and performing a peak search in the obtained X-ray peak pattern. More specifically, the d-value of the (111) plane of the face-centered cubic lattice, which is the origin of the hard film in this specification, refers to the diffraction angle of the peak of the (111) plane of the face-centered cubic lattice of chromium nitride (CrN), and the d-value of the (111) plane of the cubic crystal structure calculated according to Bragg's formula according to the following equation (1). In the following equation (1), d means: plane spacing, λ means: X-ray wavelength (1.5406 Å), and θ means: X-ray diffraction angle.

[0046] [Formula 1] .

[0047] The d-value of a hard coating, for example, can be set to a value between 2.25 Å and 2.45 Å by means of a conventional arc ion plating method to form a hard coating.

[0048] <Thickness of the hard membrane> The rigid film in this embodiment is not particularly limited, but it is preferably 4 μm or thicker. If the thickness of the rigid film is 4 μm or thicker, the durability against stress on the rigid film can be further improved, and a coated mold with superior durability can be obtained.

[0049] In this specification, "thickness of the rigid film," as described in detail in the following embodiments, refers to a value calculated by measuring the dimensional changes before and after the formation of the rigid film.

[0050] The thickness of the rigid film is more preferably 5 μm or more, and even more preferably 6 μm or more. Furthermore, the upper limit of the thickness of the rigid film is not particularly limited; for example, the thickness of the rigid film is preferably 10 μm or less, and more preferably 8 μm or less.

[0051] Thus, the coated die in this embodiment has excellent durability, so it can be appropriately used even for cold forging punches used in harsh environments, for example.

[0052] 2. Other structures of the coating mold In this embodiment, to further improve the adhesion between the mold and the rigid film, a base layer may also be provided between the mold and the rigid film as needed.

[0053] In particular, when the substrate material of the mold is an iron-based alloy (e.g., SKD material, SKS material, etc.) or a high-speed tool steel (e.g., HSS, etc.), from the viewpoint of reliably suppressing the possibility of film peeling from the substrate material, it is preferable to provide a base layer between the mold and the hard film.

[0054] As a base layer, it can be formed, for example, from any one or more layers selected from hard films containing metal elements that do not meet the aforementioned conditions for a hard film, such as nitrides, carbonitrides, oxides, or oxynitrides, metals, nitrides, carbonitrides, and carbides. Furthermore, as long as the durability of the aforementioned hard film is not compromised, one or more layers made of the aforementioned materials can be formed on the hard film formed on the outer surface of the mold.

[0055] Furthermore, in this embodiment, a second hard film (hereinafter referred to as a "first hard film") may be formed on top of the hard film formed on the outer surface of the mold (hereinafter referred to as the "first hard film"), having a different composition and / or physical properties than the first hard film but satisfying the aforementioned conditions for a hard film. Additionally, a third hard film (hereinafter referred to as a "third hard film") that satisfies the aforementioned conditions for a hard film may be formed on top of the films to which they are stacked.

[0056] Alternatively, the first hard coating and the second hard coating (or the first hard coating, the second hard coating, and the third hard coating) can be stacked on top of each other. Furthermore, the first hard coating and the second hard coating (or the first hard coating, the second hard coating, and the third hard coating) can be stacked in two or more alternating layers. Alternatively, as long as the durability of the aforementioned hard coating is not compromised, layers containing any one or more of the following—a hard coating, a metal, a nitride, a carbonitride, or an oxynitride—that do not meet the aforementioned conditions for a hard coating can be sandwiched between the stacked structures of such multiple hard coatings of this embodiment.

[0057] In the case of forming one or more such base layers, upper layers and / or different rigid films, there is no particular limitation, but the total thickness of the laminate is preferably less than 10 μm.

[0058] 3. Manufacturing method of coating mold The coated mold in this embodiment can be manufactured by coating (forming) a hard film on at least a portion of the outer surface of the mold. Sputtering or arc ion plating can be used for coating the hard film.

[0059] In sputtering, argon gas is introduced in addition to nitrogen as the reactant gas during film formation to sputter the target material. Normally, argon, being an inert gas, does not react with the sputtered metal particles and is not included in the film. However, because ionized argon possesses energy and collides with the substrate (mold) under a negative voltage, some argon is mixed into the film. If some argon is mixed into the film, defects may occur, potentially leading to a decrease in film strength. Therefore, when sputtering is used to form a hard film for molds used under high load conditions, it may result in a premature shortening of the mold's lifespan.

[0060] Therefore, in the coating of a hard film onto a mold, arc ion plating is preferred. Furthermore, in arc ion plating, a film-forming apparatus equipped with a cathode having permanent magnets on the back and periphery of the target is preferred.

[0061] A film-forming apparatus used in arc ion plating typically includes: an arc evaporation source with a target material serving as a hard film; an anode, which becomes the destination for electrons during arc discharge; an arc power source for applying arc current to the target material; a furnace (vacuum container) housing a mold serving as a substrate; a substrate rotation mechanism for rotating the substrate within the furnace; a bias power source for applying a bias voltage to the substrate; a heater for heating the furnace and the substrate; a vacuum pump for maintaining a vacuum within the furnace; and a gas inlet for introducing either or both of an inactive gas (helium, neon, argon, krypton) and a reactive gas (nitrogen, hydrocarbon, oxygen) into the furnace. Furthermore, the film-forming apparatus preferably includes a filtration mechanism that reduces large particles (droplets) of the film-forming material using a magnetic field.

[0062] The film-forming method will be explained in detail below.

[0063] First, a vacuum is created inside the furnace by evacuation. The preferred vacuum pressure at this point is 10 × 10⁻⁶. ﹣3 Below Pa. A vacuum pressure of 5 × 10⁻⁶ is more preferred. ﹣3 Below Pa, 1×10 is further preferred. ﹣3 Pa below. By performing vacuuming, oxidation of the substrate caused by starting heating the substrate in a state with a large amount of residual gas in the furnace can be prevented.

[0064] After vacuuming, the substrate is heated. The heating temperature is preferably set to 400℃~550℃, more preferably 420℃~520℃, and even more preferably 450℃~500℃. Heating the substrate within this temperature range prevents a decrease in film adhesion due to insufficient diffusion at the substrate-film interface caused by excessively low temperatures, and also prevents the substrate material from softening due to heat.

[0065] Next, the substrate is etched. Etching can be performed by introducing an inert gas into the furnace, plasmaizing the inert gas, and causing the inert gas ions to collide with the substrate to which a negative bias voltage is applied. Alternatively, the mounted arc evaporation source can be discharged at any point along with the inert gas, ionizing the metal target mounted on the arc evaporation source and the inert gas at any point, causing them to collide with the substrate, thereby enabling etching. If the arc evaporation source is discharged without using an inert gas, etching can be performed using only metal ions.

[0066] When etching is performed by plasmaizing inactive gases, the furnace pressure is preferably 0.1 Pa to 5 Pa. If the inactive gas pressure is too low, the amount of inactive gas ions generated may be insufficient, resulting in inadequate etching. On the other hand, if the inactive gas pressure is too high, ionized inactive gases may collide with unionized inactive gases, also resulting in insufficient etching.

[0067] In etching processes where a metal target is ionized by an arc evaporation source discharge, the arc current is preferably set to 50A to 150A. If the arc current is too low, it may be difficult to generate an arc discharge, resulting in insufficient etching. On the other hand, if the arc current is too high, while more ions may be generated, improving the etching effect, other problems arise. Specifically, if the arc current is too high, more droplets (large particles) formed from a portion of the molten target material are generated, which adhere to the substrate surface, roughening the substrate surface. This roughness of the substrate (mold) surface affects the surface roughness Ra of the hard coating. Therefore, to obtain the desired surface roughness Ra of the hard coating and to suppress the generation of large particles, the arc current is preferably not too high.

[0068] From the viewpoint of both achieving sufficient etching effect and suppressing the generation of large particles, the arc current is preferably set within the aforementioned range of 50A to 150A. Furthermore, to reduce the adhesion of the generated large particles to the substrate, the arc evaporation source of the film-forming apparatus is preferably equipped with a filtration mechanism utilizing a magnetic field.

[0069] During etching, a negative bias voltage is applied to the substrate. From the viewpoint of obtaining a sufficient etching effect, the applied voltage is preferably -100V to -1000V. If the bias voltage applied to the substrate is too low, a sufficient etching effect may not be obtained. On the other hand, if the voltage is too high, there is a possibility of abnormal discharge occurring on the substrate surface, which may damage the substrate.

[0070] After etching, a hard film is formed onto the substrate. During film formation, a reactive gas is introduced into the furnace. To stabilize the discharge, an inactive gas may also be mixed with the reactive gas. However, there are cases where the inactive gas fails to react with the evaporated metal material and remains in the film, ultimately causing defects in the film. Therefore, when forming a hard film by mixing the reactive gas and the inactive gas, the residual content of the inactive gas in the hard film is preferably less than 5%, more preferably less than 1%.

[0071] In this specification, the amount of residual inactive gas components in the hard coating is defined as the amount measured using an EDS (detector: X-act C3400, analysis software: INCA) manufactured by Oxford Instruments Co., Ltd., attached to a scanning electron microscope (Hitachi High Technology Field Manufacturing Co., Ltd., S-3400N).

[0072] As the reactant gas, hydrocarbon gases such as nitrogen, oxygen, and methane can be selected, depending on the application. For example, in the case of forming Al and Cr nitrides, nitrogen can simply be introduced into the furnace as the reactant gas.

[0073] To form a dense and high-strength nitride-containing hard film, the furnace pressure during film formation is preferably 1 Pa to 10 Pa, more preferably 2 Pa to 8 Pa, and even more preferably 4 Pa ​​to 6 Pa. If the pressure is too low, the reaction between the evaporated metal and the reactive gas becomes insufficient, and the desired nitride cannot be formed. On the other hand, if the pressure is too high, the evaporated metal ions may collide with the reactive gas, and these ions may reach the substrate in a state of energy loss. As a result, these ions may no longer be able to diffuse sufficiently on the substrate surface, failing to form a dense film and thus causing a decrease in film strength.

[0074] Preferably, the absolute value of the negative bias voltage applied to the substrate gradually increases from the vicinity of the substrate towards the surface of the hard coating. For example, it is preferable that the absolute value of the negative bias voltage applied to the substrate gradually increases from the vicinity of the substrate towards the surface of the hard coating within the range of -50V to -200V. If the bias voltage is too low, the precipitation of soft hexagonal AlN (aluminum nitride) into the coating may lead to a decrease in the hardness of the hard coating. On the other hand, if the bias voltage is too high, the energy of metal ions and gas ions that collide with the substrate due to the negative voltage may increase, increasing the effect of knocking on the coating deposited on the substrate (ion knocking effect). As a result, the strain of the coating may increase, leading to increased stress. If the stress increases excessively, it can cause the coating to peel off.

[0075] From the viewpoint of both forming a film with such high hardness and suppressing peeling on the substrate, the bias voltage during film formation is preferably set within the aforementioned range of -50V to -200V.

[0076] Preferably, the arc current energizing the target material gradually increases from the vicinity of the substrate of the hard film toward the vicinity of the surface. For example, it is preferable that the arc current applied to the target material gradually increases from the vicinity of the substrate of the hard film toward the vicinity of the surface within the range of 50A to 200A.

[0077] By forming a hard film using an arc ion plating method with a film-forming apparatus equipped with a permanent magnet, a filter mechanism, etc., as described above, a hard film with excellent surface smoothness can be easily obtained. Furthermore, by varying the absolute value of the negative bias voltage applied to the substrate and the arc current energizing the target as described above, it is possible to control the crystal structure near the substrate (near the mold) and near the surface of the hard film to be different. As a result, the crystal structure of the final hard film is oriented with either a (111) or (200) plane in a cubic crystal structure, and the d-value of the interplanar spacing of the (111) plane can be made to be 2.25 Å or more and 2.45 Å or less.

[0078] In other words, according to such an arc ion plating method, it is easier to form a hard film that meets the aforementioned conditions of surface roughness Ra and d value of the (111) plane of the cubic crystal.

[0079] This specification discloses various techniques as described above, but the main techniques are summarized below.

[0080] The coating mold of the first aspect of the present invention has a mold and a hard film formed on at least a portion of the outer surface of the mold; the hard film contains a nitride, carbonitride, oxide or oxynitride of a metal element; in the total amount of the aforementioned metal element contained in the hard film, the Al content is 65 atomic% or more, the Cr content is 15 atomic% or more, and the total content of Al and Cr is 80 atomic% or more and 100 atomic% or less; the surface roughness Ra of the hard film is 0.05 μm or less; the d value of the (111) plane of the face-centered cubic lattice of the hard film is 2.25 Å or more and 2.45 Å or less.

[0081] The coating mold of the second aspect of the present invention is the coating mold of the first aspect, wherein the surface roughness Ra of the aforementioned hard film is less than 0.04 μm.

[0082] The coating mold of the third aspect of the present invention is the coating mold of the first or second aspect, wherein the aforementioned hard film is composed of a nitride of a metal element; in the total amount of the aforementioned metal element contained in the aforementioned hard film, the Al content is 65 atomic% to 80 atomic% and the Cr content is 20 atomic% to 35 atomic% and the total content of Al and Cr is 100 atoms.

[0083] The coating mold of the fourth aspect of the present invention is the coating mold of the first to third aspects, and the aforementioned mold is for cold plastic processing.

[0084] The coating die of the fifth aspect of the present invention is the coating die of the first to fourth aspects, wherein the aforementioned die is a punch used to plastically process the workpiece by colliding with it.

[0085] The coating mold of the sixth aspect of the present invention is the coating mold of the first to fifth aspects, wherein the mold is made of iron-based alloy or high-speed tool steel; and a base layer is provided between the mold and the hard film. Example

[0086] The present invention will now be described in more detail with the aid of embodiments, but the present invention is not limited to the embodiments at all.

[0087] 1. Formation of a hardened film onto a punch that serves as a mold. In Examples 1-3 and Comparative Examples 1-2, a coated die for cold forging (hereinafter also referred to as "coated punch") with a hard film formed on the punch serving as a mold was actually manufactured. Various physical properties of the hard film were measured and calculated, and the durability of the coated punch was evaluated.

[0088] The methods for measuring and calculating the various physical properties of hard coatings and the details of the molds (punches) used are as follows.

[0089] [Method for measuring the average composition of metallic elements contained in a hard coating] The average composition of metallic elements in the hard coating was calculated by using an Oxford Instruments EDS (detector: X-act C3400, analysis software: INCA) manufactured by Hitachi High-Tech Field Manufacturing Co., Ltd., attached to a scanning electron microscope (S-3400N, manufactured by Hitachi High-Tech Field Manufacturing Co., Ltd.). Measurements were performed on the coating thickness of the calotest cross-section under conditions of 15 kV accelerating voltage, 50 s effective measurement time, and 4 repetitions. The average composition of argon gas contained in the hard coating was also measured using the same method.

[0090] [Method for calculating the thickness of rigid coating] The thickness of the hard coating was calculated by measuring the dimensional changes before and after the formation of the hard coating using a micrometer (Mittoyo Corporation).

[0091] [Method for calculating the d-value of hard coating] Regarding the d-value of the hard coating, firstly, the crystal structure of the hard coating was identified using an X-ray analysis apparatus (Rigaku Corporation, "SmartLab") under the following conditions (1). Then, the obtained X-ray peak shape was determined by peak search under the following conditions (2). Specifically, the diffraction angles of the peaks on the (111) plane of the face-centered cubic lattice of chromium nitride (CrN) were determined, and the interplanar spacing d-value of the (111) plane of the cubic crystal structure was calculated according to the Bragg formula of the aforementioned equation (1).

[0092] (1) Measurement conditions for X-ray diffraction Target material: Cu Target output: 40kV-40mA 45kV-200mA Filter: Kβ filter Incident monochromator: CBO unit (Cu & Co) Counting monochromator: Not used Counter: Blink Counter Slit: Divergence: 1mm, Divergence Longitudinal Restriction: 10mm, Scattering: Open, Light Reception: Open Scanning speed: 1° / min Sampling width: 0.01° Scan axis: 2θ / θ Measurement angle (2θ): 30°~46° θ offset: 0° Total number of times: 1 (2) Conditions for peak search Method: Secondary Differential Method Peak width threshold: 0.25° Peak intensity threshold: 50 cps.

[0093] [Method for measuring the surface roughness Ra of hard coating (immediately after hard coating is formed or after grinding (post-treatment))] The surface roughness Ra (arithmetic mean height) of the hard coating was measured according to JIS-B-0601 (2001) using a surface roughness / profile shape composite measuring machine (SURFCOM NEX Co., Ltd.). Specifically, a coated punch was placed on a sample stage, and the surface roughness of the functional part of the punch substrate with the hard coating formed was measured under the following conditions. In addition, the surface roughness Ry (maximum height) of the hard coating, as well as the surface roughness Ra and surface roughness Ry of the punch surface before the hard coating was formed, were also measured using the same method.

[0094] ·condition Measurement category: Roughness measurement Deadline Category: 2RC Tilt Correction: Least Squares Linear Correction Measurement length: 1.3mm Cutoff wavelength: 0.25mm Measurement magnification: 10,000x Measurement speed: 0.15 mm / second.

[0095] [Mold] As a mold, a punch for cold forging and front extrusion processing is used. Specifically, a punch made of superhard alloy of CIS specification VC30 (CIS019D classification) is used. More specifically, the experimental punch is made by grinding and machining the raw material made of this superhard alloy to give it the following shape.

[0096] exist Figure 1 The diagram shows a schematic top view used to illustrate the shape of the punch in the embodiment. Figure 1 In the accompanying drawings, the reference numerals indicate the punch 1, the functional part 2, the gripping part 3, and the upper part 4. Additionally, Figure 1 The punch 1 shown is roughly cylindrical in shape. For example... Figure 1 As shown, the punch 1 includes a functional part 2 that contacts the workpiece during forging and a holding part 3 of length C for holding by the forging device. The upper end 4 is the end face of the functional part 2. Specifically, the length L of the functional part 2 is set to 116 mm relative to the length direction of the punch 1, and the length C of the holding part 3 is set to 260 mm. More specifically, by performing grinding and cutting processes, such as... Figure 1 Enlarged view of part E Figure 2 As shown, the end diameter L1 of punch 1 is set to 24.65mm, the clearance diameter L2 is set to 24.5mm, the radius of the arc formed by the end point P1 is set to 1.5mm, the clearance angle α is set to 1.5°, and the end angle β of the upper end 4 is set to 9°. Overall, as... Figure 1 and Figure 2 The configuration shown is such that the end diameter L1 of the punch 1 and the diameter reduction portion of the punch 1 along the length direction are connected in a smooth arc shape.

[0097] After grinding and cutting, mirror polishing is performed on the outer surface of the functional part 2, including the upper end 4 where a hard film is subsequently formed, so that the surface roughness Ra (arithmetic mean height) is less than 0.03 μm and the surface roughness Ry (maximum height) is less than 0.3 μm.

[0098] Then, by forming a hardened film on the punch thus made using different methods, the coated punches in Example 1 and Comparative Example 1 are manufactured. The manufacturing methods of each coated punch will be described in detail below.

[0099] (Example 1) In Example 1, a film-forming apparatus equipped with a permanent magnet and a filtration mechanism is used to form a hard film on a punch to manufacture a coated punch. The structure of the film-forming apparatus and the specific method for forming the hard film are described below.

[0100] [Film-forming device] In the formation (film formation) of a hard film onto the surface of a substrate (in this embodiment 1, the surface of the functional part of the punch), a film-forming apparatus using an arc ion plating method is employed. The detailed structure of this film-forming apparatus is as follows. The apparatus includes multiple cathodes (arc evaporation sources), a vacuum container, and a substrate rotation mechanism. In the cathodes, an electromagnetic coil for plasma focusing is provided on the front surface of the target, and a permanent magnet is provided on the back side of the target. Furthermore, the cathodes are equipped with a filtration mechanism that reduces droplets using a magnetic field. The interior of the vacuum container is vented by a vacuum pump, and gas is introduced into the vacuum container from a supply port located within the container. A bias power supply is connected to the substrates located within the vacuum container, allowing multiple substrates to be independently subjected to negative bias voltages. The substrate rotation mechanism includes a worktable, a plate-shaped clamp mounted on the worktable, and a tubular clamp mounted on the plate-shaped clamp. In the substrate rotation mechanism, the worktable rotates at a speed of 1.5 revolutions per minute. The plate-shaped clamp and the tubular clamp are each capable of rotating on their own axis and revolving around a central point.

[0101] [Heating and vacuum degassing process (pre-film formation process)] Initially, the functional part of the punch, which serves as the substrate, is fixed in a tubular clamp inside the vacuum chamber of the film-forming apparatus, and the pre-film-forming process is performed as follows. Specifically, the vacuum chamber is first evacuated to 5 × 10⁻⁶. ﹣3 Pa or less. Then, it is heated by a heater installed inside the vacuum container until the temperature of the functional part of the punch reaches 500°C.

[0102] [Ar bombardment process (pre-film formation process)] Then, Ar gas is introduced into a vacuum container, and an electric current flows through the wire to generate Ar ions. Subsequently, a negative bias voltage is applied to the functional part of the punch to perform Ar bombardment.

[0103] [Film Forming Process] After Ar bombardment, the gas inside the vacuum container is replaced with nitrogen, and the pressure inside the vacuum container is set to 4 Pa. Then, power is supplied to the cathode, and a negative bias voltage is applied to the functional portion of the punch, which serves as the substrate, to form an Al and Cr nitride (hard film) of approximately 5 μm. In this Example 1, a cathode with an Al content of 75 atomic% and a Cr content of 25 atomic% was used. Furthermore, the bias voltage varies (tilts) in the range of -70V to -200V, gradually increasing in absolute value from the vicinity of the functional portion of the punch (near the substrate) towards the surface of the hard film. The arc current also varies (tilts) in the range of 70A to 180A, gradually increasing in absolute value from the vicinity of the functional portion of the punch (near the substrate) towards the surface of the hard film.

[0104] For the coated punch in Example 1 manufactured in this way, the various physical properties of the hard film after the film is formed are measured and calculated using the aforementioned method.

[0105] Finally, as a prerequisite for the subsequent durability test of the coated punch, the outer surface of the functional part of the coated punch in Example 1 was mirror-polished again. The surface roughness Ra of the functional part of the coated punch after polishing was adjusted to 0.05 μm or less (more specifically, the surface roughness Ra was adjusted to 0.03 μm), and the surface roughness Ry was adjusted to 0.5 μm or less. The measurement and calculation results of various physical properties of the aforementioned hard film, as well as the value of the surface roughness Ra of the hard film after polishing (post-treatment), are summarized in Table 1 below.

[0106] The method for evaluating the durability of the coated punch is as follows. The evaluation results of the coated punch in Example 1, together with those of other examples and comparative examples, are summarized and described below.

[0107] [Methods for evaluating the durability of coated punches] The durability of the coated punch was evaluated using it as a cold forging die (for front extrusion). The cold forging machine and other cold forging test conditions were as follows. Durability was evaluated by observing the coated punch after use as a cold forging die. Figure 3The test was performed by exposing the base material of the cross-section of the coated punch (specifically, the functional part of the coated punch) at various angles. If almost no base material of the coated punch is observed at any angle, the coated punch is judged to have good durability. If a large amount of base material of the coated punch is observed at any angle, the coated punch is judged to have poor durability.

[0108] (Conditions for cold forging test) Cold forging forming machine: "BPF-680SSUL" manufactured by Sakamura Machinery Co., Ltd. Die: Hard alloy punch (coated punch of the example or comparative example) Process: Process 2 Construction method: Front extrusion Machining depth: 110mm Reduction rate: 50%–65% Rotation speed: 40-50 revolutions per minute Raw material to be formed: alloy steel Application: Automotive parts Lubrication: Phosphate-treated and forging oil (chlorine-free) Number of units processed: 6,000 to 7,000.

[0109] (Example 2) In Example 2, except that a cathode with an Al content of 70 atomic% and a Cr content of 30 atomic% was used, the coated punch was manufactured using the same method as in Example 1. Similar to Example 1, for the coated punch manufactured in Example 2, various physical properties of the hard film after film formation were measured and calculated using the aforementioned method. Furthermore, as in Example 1, the surface roughness Ra and surface roughness Ry of the functional parts of the coated punch in Example 2 were adjusted as a prerequisite for durability testing. The measurement and calculation results of various physical properties of the hard film in Example 2, as well as the value of the surface roughness Ra of the hard film after grinding treatment (post-treatment), are summarized and presented in Table 1 below. Then, as in Example 1, the durability of the coated punch in Example 2 was also evaluated. The evaluation results of the coated punch in Example 2, along with other examples and comparative examples, are summarized and described below.

[0110] (Example 3) In Example 3, except that a cathode with an Al content of 80 atomic% and a Cr content of 20 atomic% was used, the coated punch was manufactured using the same method as in Example 1. Similar to Example 1, for the coated punch manufactured in Example 3, various properties of the hard film after film formation were measured and calculated using the aforementioned method. Furthermore, as in Example 1, the surface roughness Ra and surface roughness Ry of the functional parts of the coated punch in Example 3 were adjusted as a prerequisite for durability testing. The measurement and calculation results of various properties of the hard film in Example 3, as well as the value of the surface roughness Ra of the hard film after grinding treatment (post-treatment), are summarized and presented in Table 1 below. Then, as in Example 1, the durability of the coated punch in Example 3 was also evaluated. The evaluation results of the coated punch in Example 3, along with other examples and comparative examples, are summarized and described below.

[0111] (Comparative Example 1) In Comparative Example 1, except that a hard film was formed using a film-forming apparatus (manufactured by Kobe Steel Co., Ltd.) that has a permanent magnet but no filter mechanism, a negative bias voltage of 60V was set during film formation, and an arc current of 120A was set during film formation, the coated punch was manufactured by the same method as in Example 1.

[0112] Similar to Example 1, the various physical properties of the hard film after film formation were measured and calculated using the aforementioned method for the coated punch manufactured in Comparative Example 1. Furthermore, as in Example 1, the surface roughness Ra and surface roughness Ry of the functional parts of the coated punch in Comparative Example 1 were adjusted as a preparatory step for the durability test. However, the surface roughness Ra of the hard film in Comparative Example 1 immediately after formation was coarse to 0.25 μm, and even after performing the same mirror polishing treatment as in Example 1, the surface roughness Ra of the hard film after polishing (post-treatment) was a value higher than 0.05 μm. The measurement and calculation results of various physical properties of the hard film in Comparative Example 1, as well as the value of the surface roughness Ra of the hard film after polishing (post-treatment), are summarized and presented in Table 1 below. Then, as in Example 1, the durability of the coated punch in Comparative Example 1 was also evaluated. The evaluation results of the coated punch in Comparative Example 1 are summarized and described below along with those of other examples and comparative examples.

[0113] (Comparative Example 2) In Comparative Example 2, except that two cathodes were used for film formation—one having an Al content of 62 atomic% and a Cr content of 38 atomic% and the other having an Al content of 50 atomic% and a Ti content of 50 atomic%—a coated punch was manufactured using the same method as in Comparative Example 1. Specifically, unlike Comparative Example 1, Comparative Example 2 had a three-layer structure: a first layer formed on the surface of the functional portion of the punch, which served as a substrate, and composed of AlTiN; a second layer formed on top of the first layer and composed of AlTiN and AlCrN; and a third layer formed on top of the second layer and composed of AlCrN. In the first layer, the average composition of the metallic elements contained in the hard film was 50 atomic% Al and 50 atomic% Ti. In the second layer, the average composition of the metallic elements contained in the hard film was 56 atomic% Al, 25 atomic% Ti, and 19 atomic% Cr. In the third layer (a hard film formed on the outer surface of the punch), the average composition of the metallic elements contained in the hard film is 62 atomic% Al and 38 atomic% Cr. In addition, the film formation time is adjusted so that the thickness ratio of each layer is 1 (first layer): 3 (second layer): 1 (third layer).

[0114] Similar to Example 1, the various physical properties of the hard film after film formation were measured and calculated using the aforementioned method for the coated punch manufactured in Comparative Example 2. Furthermore, as in Example 1, adjustments were made to the surface roughness Ra and surface roughness Ry of the hard film formed as the third layer of the functional part of the coated punch in Comparative Example 2, similar to Example 1. However, the surface roughness Ra of the hard film in Comparative Example 2 immediately after formation was coarse to 0.20 μm, and even after performing the same mirror polishing treatment as in Example 1, the surface roughness Ra of the hard film (third layer) after polishing (post-treatment) was a value higher than 0.05 μm. The measurement and calculation results of various physical properties of the hard film in Comparative Example 2, as well as the value of the surface roughness Ra of the hard film (third layer) after polishing (post-treatment), are summarized in Table 1 below. Then, as in Example 1, the durability of the coated punch in Comparative Example 2 was evaluated. The evaluation results of the coated punch in Comparative Example 2, together with the other embodiments and comparative examples, will be summarized and described below.

[0115] Table 1 below summarizes the physical properties of the hard coatings in the coated punches of Examples 1-3 and Comparative Examples 1-2. Furthermore, the hard coatings of the coated punches of Examples 1-3 and Comparative Examples 1-2 do not contain any residual inactive gas (specifically argon). Figure 4The image shows cross-sectional views of the coated punch from various angles after the cold forging test in Example 1. Figure 5 The image shows cross-sectional views of the coated punch from various angles after the cold forging test in Example 2. Furthermore, in Figure 6 The image shows cross-sectional views of the coated punch from various angles after the cold forging test in Example 3. Figure 7 The image shows cross-sectional views of the coated punch from various angles after the cold forging test in Comparative Example 1. Figure 8 The image shows cross-sectional views of the coated punch at various angles after the cold forging test in Comparative Example 2.

[0116] [Table 1] .

[0117] As shown in Table 1 above, the coated punches in Examples 1-3 exhibit low surface roughness Ra values ​​in the hard film not only after grinding (post-treatment) but also immediately after the hard film is formed, demonstrating good surface smoothness. Furthermore, as... Figures 4-6 As shown, after the cold forging test, the coated punches in Examples 1 to 3 showed almost no exposure of the base material at any angle, indicating good durability.

[0118] On the other hand, as shown in Table 1 above, the surface roughness Ra of the hard film on the coated punches in Comparative Examples 1-2 after grinding (post-treatment) also became a relatively high value, exceeding 0.05 μm, indicating poor surface smoothness. Furthermore, as... Figure 7 As shown, in Comparative Example 1, the coated punch exhibited a maximum exposure of approximately 600 μm of the punch base material at 0° after the cold forging test, indicating poor durability. Furthermore, as... Figure 8 As shown, the coated punch in Comparative Example 2 also showed a maximum exposure of the punch base material of about 300 μm at 270° after the cold forging test, indicating poor durability.

[0119] 2. Formation of rigid film onto test pieces made of SKD material In Examples 4 and 5, a test piece made of SKD material was used as the substrate instead of a punch, and a coated test piece with a hard film formed on the test piece was fabricated. Furthermore, as a reference evaluation, the adhesion between the test piece and the film was observed in Examples 4 and 5.

[0120] (Example 4) In Example 4, except that a test piece made of SKD material, which is an iron-based alloy, was used as the substrate, a coated test piece was prepared using the same method as in Example 1 of 1. Furthermore, similar to Example 1 of 1., various physical properties of the hard film after film formation were measured and calculated for the coated test piece prepared in Example 4 using the method described in 1. Furthermore, as a reference evaluation, the adhesion between the test piece and the hard film was observed for the prepared coated test piece.

[0121] (Example 5) In Example 5, except for forming a CrN substrate layer between the test piece and the hard film made of AlCrN, the coated test piece was prepared using the same method as in Example 4. Specifically, firstly, a cathode having a composition of 100 atomic% Cr was used, with a bias voltage set to -50V and an arc current set to 150A, to form a CrN substrate layer on the surface of the test piece until the film thickness reached 1 μm. Next, using the same film-forming method described in Example 1 of 1 above, a hard film made of AlCrN was formed on the CrN substrate layer. In detail, in the formation of the hard film made of AlCrN on the substrate layer, a cathode having a composition of 75 atomic% Al and 25 atomic% Cr was used. The bias voltage was varied (tilted) in the range of -70V to -200V, gradually increasing in absolute value from the vicinity of the CrN substrate layer toward the vicinity of the surface. The arc current is also varied (tilted) in the range of 70A to 180A, gradually increasing from the vicinity of the CrN substrate towards the vicinity of the surface. At this time, film formation is carried out to make the thickness of the hard film composed of AlCrN 5μm.

[0122] Similar to Example 4, for the coated test piece produced in Example 5, various physical properties of the hard film after film formation were measured and calculated using the method described in section 1 above. Furthermore, for the produced coated test piece, the adhesion between the test piece and the base layer and the hard film was observed as a reference evaluation.

[0123] Table 2 below summarizes the physical properties of the rigid coatings in the coated test pieces of Examples 4-5. Furthermore, the rigid coatings in the coated test pieces of Examples 4-5 do not contain any residual inactive gas (specifically argon).

[0124] [Table 2] .

[0125] As shown in Table 2 above, even without grinding (post-processing) after the hard coating is formed, the coated test pieces in Examples 4 and 5 exhibit low surface roughness Ra values ​​and good surface smoothness immediately after the hard coating is formed. Furthermore, in the coated test piece of Example 4, slight peeling of the hard coating was observed between the test piece and the hard coating, albeit in a small area. On the other hand, no such peeling of the hard coating was observed in the coated test piece of Example 5. Based on these results, it is preferable to provide a base layer between the mold and the hard coating when the substrate material of the mold is made of SKD material, from the viewpoint of reliably suppressing the possibility of coating peeling.

[0126] This application is based on Japanese Patent Application No. 2023-158820, filed on September 22, 2023, and Japanese Patent Application No. 2024-100601, filed on June 21, 2024, the entire contents of which are incorporated herein by reference.

[0127] It should be understood that the embodiments and examples disclosed herein are illustrative and not restrictive in all respects. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0128] Industrial availability According to embodiments of the present invention, a coated die with excellent durability can be obtained. In particular, from the viewpoint of use in particularly harsh environments, the coated die of this embodiment is preferably applied to cold forging dies.

Claims

1. A coating mold, characterized in that, It has a mold and a hard film formed on at least a portion of the outer surface of the aforementioned mold; The aforementioned hard coating comprises nitrides, carbonitrides, oxides, or oxynitrides of metallic elements; In the total amount of the aforementioned metallic elements contained in the aforementioned hard coating, the Al content is more than 65 atomic% and the Cr content is more than 15 atomic% and the combined content of Al and Cr is more than 80 atomic% and less than 100 atomic%. The surface roughness Ra of the aforementioned hard film is below 0.05 μm; The aforementioned hard film is caused by the d value of the (111) plane of the face-centered cubic lattice being above 2.25 Å and below 2.45 Å.

2. The coating mold as described in claim 1, characterized in that, The surface roughness Ra of the aforementioned hard film is below 0.04 μm.

3. The coating mold as described in claim 1, characterized in that, The aforementioned hard coating is composed of nitrides of metallic elements; Of the total amount of the aforementioned metallic elements contained in the aforementioned hard coating, the Al content is 65 atomic% to 80 atomic% and the Cr content is 20 atomic% to 35 atomic% and the total content of Al and Cr is 100 atoms.

4. The coating mold as described in claim 1, characterized in that, The aforementioned mold is for cold plastic processing.

5. The coating mold as described in claim 1, characterized in that, The aforementioned mold is a punch used to plastically process the workpiece by colliding with it.

6. The coating mold as described in claim 1, characterized in that, The aforementioned mold is made of iron-based alloy or high-speed tool steel; There is a base layer between the aforementioned mold and the aforementioned rigid film.

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