JP5920681B2 - Coated mold for plastic working excellent in sliding characteristics and manufacturing method thereof - Google Patents

Description

  The present invention relates to a coating die for plastic working that requires sliding characteristics such as wear resistance and galling resistance in a sliding environment with a workpiece such as a press working or forging die.

  In recent years, tools such as molds and drills have been used more severely, and further life improvement is required. Of these, wear such as wear and galling is caused by the sliding of the work surface of the tool and the workpiece, and is particularly noticeable in plastic working tools such as press working and forging dies in a severe sliding environment. In view of this, a technique for improving the wear resistance and galling resistance of the work surface by applying various surface treatments to the work surface of the tool has been widely implemented. In particular, the coating (coating) method can coat a hard film with a Vickers hardness exceeding HV1000 and has excellent adhesion to the substrate surface, so the life of the coated tool to which it is applied is greatly improved. .

For example, titanium carbide coated by chemical vapor deposition (CVD) (represented by TiC as an elemental structure; hereinafter the same), VC coated by salt bath, physical vapor deposition (PVD) All coatings of HV2000 or more, such as TiCN, TiC, VCN, VC, and AlCrN coated by the above method, have been put into practical use. Among various types of coating means, the PVD method that enables the temperature during coating to be a low temperature equal to or lower than the tempering temperature is effective for coating the tool.
In the mold for plastic processing, where the work material has high strength, the processed product has high precision, and the molding cycle speed is increasing, the load on the work surface is particularly increased, so a hard coating is formed. In many cases, TiCN or TiC having a high hardness and a low friction coefficient is used for cold working.

Recent molds are required to have excellent heat resistance so as to be able to cope with hot working in addition to further strengthening the work material and making the mold complex. On the other hand, as the hard film using the PVD method for the mold, the third element is added to the AlCr-based nitride film having excellent wear resistance and oxidation resistance, for example, There are AlCrSi-based nitride films (Patent Documents 1 and 2). Further, the hard film of the cutting tool includes an AlCrV-based nitride film (Non-Patent Document 1) and an AlVCrSi-based nitride film. (Patent Document 3)
Furthermore, a laminated structure of AlCr nitride and V nitride is disclosed as a hard coating suitable for a cutting tool and a sliding member. (Patent Document 4)

JP 2005-042146 A Japanese Patent Laid-Open No. 2003-321764 JP 2005-262388 A Japanese Patent Laid-Open No. 2005-256081

R. Franz et al., “Influence of phase transition on the tribological performance of arc-evaporated AlCrVN hard coatings, Surface & Coatings Tech. 1101-1105

In order to further improve the life of the coated tool, it is necessary to combine the above-mentioned hard coating with excellent wear resistance, heat resistance and sliding characteristics.
In this case, the AlCrSi-based nitride films of Patent Documents 1 and 2 have high hardness and excellent heat resistance, but have a large frictional resistance during product molding, and there is room for improvement in sliding characteristics. The AlCrV-based nitride film described in Non-Patent Document 1 is excellent in heat resistance and sliding characteristics, but has low film hardness and a problem in wear resistance. And even if it is the AlVCrSi type | system | group nitride film of patent document 3, the multicomponent system component adjustment is not easy but a subject remains. Furthermore, even if the laminated structure of AlCr nitride and V nitride of Patent Document 4 is used, there is room for improvement in wear resistance.

  Therefore, an object of the present invention is to provide a coating die for plastic working and a method for manufacturing the same, which is excellent in sliding characteristics on the work surface even in a cold to warm usage environment.

  The present inventors have paid attention to a wear mechanism generated in the hard coating in a plastic working coating mold in a sliding environment with a workpiece. The wear mechanism of hard coatings is caused by wear due to low hardness and heat resistance of the coating itself, and damage caused through the deposits due to local adhesion of the workpiece. I found out that there was. Therefore, as a result of research on a technique capable of simultaneously suppressing both of these wears, it was found that there is an advantageous film form for this suppression, and there is an element configuration and a film structure to express it.

That is, the present invention is a plastic working coating mold in which a hard coating is coated on the surface of a tool substrate, and the hard coating is formed by alternately laminating nitrides of AlCrSi and nitrides of V. In other words, the coating film mold for plastic working is excellent in sliding characteristics, in which the film thickness is 3 μm or more, the surface roughness is Ra <0.2 μm, Rz <2.0 μm, and Rsk <0. Moreover, since the tool life can be greatly improved by setting the film thickness of the hard coating to 8 μm or more, it is preferable.
As for the individual film thicknesses of the AlCrSi nitride and the V nitride stacked alternately, the V nitride is preferably thicker than the AlCrSi nitride. Further, the individual film thicknesses of the AlCrSi nitride and the V nitride stacked alternately are preferably 1.5 times or more the nitride of the AlCrSi. These hard coatings are more preferably coated by physical vapor deposition.
Further, the manufacturing method of the present invention is a method in which the surface of the tool base is coated with an AlCrSi nitride by physical vapor deposition using an AlCrSi alloy target in a nitrogen atmosphere, and a physics using a V metal target in a nitrogen atmosphere. By repeating the coating of V nitride by vapor deposition, a hard film having a thickness of 3 μm or more in which AlCrSi nitride and V nitride are alternately laminated is coated, and the surface of the hard film is coated with diamond paste. It is a method for producing a coating die for plastic working that is excellent in sliding properties such that Ra <0.2 μm, Rz <2.0 μm, and Rsk <0.
It is preferable to coat a hard film having a thickness of 8 μm or more in which the AlCrSi nitride and the V nitride are alternately laminated.
The current ratio of the AlCrSi alloy target and the V metal target is preferably 2.0 or less when the AlCrSi alloy target / V metal target is 2.0 or less.

  According to the present invention, the hard coating coated on the surface is excellent in wear resistance, heat resistance, and sliding properties over the cold to warm usage region, so that it is a coating for plastic working. It is possible to dramatically improve the life of the mold.

Sample No. which is an example of the present invention. 1 is a transmission electron microscope observation photograph of a cross section of 1 hard film, and is an example showing the film structure of the present invention. It is an enlarged photograph of the film | membrane surface which shows the damage form of the film | membrane by the ball-on-disk test of this invention example and a comparative example, and is an example which shows the effect of this invention.

  One of the important features of the present invention is that an optimum combination of element configurations and a coating structure capable of simultaneously suppressing wear due to the two types of mechanisms in the coated tool have been found. In other words, in order to suppress these wears, the hard coating itself is not only excellent in wear resistance and heat resistance, but also particularly excellent in sliding properties with the work material is effective in suppressing the above wear. is there.

  The inventors have also found that an AlCrSi nitride excellent in wear resistance and heat resistance and a V nitride excellent in sliding characteristics have a laminated structure. By adopting a laminated structure, the nitride of V is formed on the surface of the coating with a V oxide having excellent sliding characteristics under the usage environment of the plastic working coating mold, and the wear resistance of the nitride of AlCrSi The sliding characteristics can be greatly improved without impairing the heat resistance. Furthermore, in order to exert these effects, the inventors have found that there is an optimum film thickness and surface state of the laminated structure, and have reached the present invention. The details will be described below.

  Since the nitride of AlCrSi has a high hardness of HV3000 or higher, has excellent wear resistance, and also has excellent heat resistance, it is possible to suppress damage in the form of wear. However, according to the study of the present inventor, even in the case of AlCrSi nitride having excellent heat resistance and wear resistance, under severe sliding environment, the surface of the film during use is locally processed material. It has been found that the film tends to adhere, the sliding resistance becomes uneven on the surface of the film, and galling and seizure may occur, resulting in damage to the film. In particular, when the work material is Fe-based, Fe oxide generated from the work material may damage the coating surface.

On the other hand, when a compound mainly composed of V is suitably oxidized in the temperature range of 25 to 200 ° C. and formed as a thin oxide layer on the surface of the base material, the nitride of V becomes a counterpart material ( In order to reduce the affinity with the workpiece, it was confirmed that the sliding properties are excellent.
And even when the workpiece is Fe-based, the oxide of V reacts with the Fe oxide and softens the Fe oxide, so the aggression to the film is reduced and the sliding resistance is suppressed, Furthermore, it has been found that the microcrystalline Fe oxide adheres thinly and evenly immediately above the V oxide formed on the surface of the film, so that the Fe oxide itself is also caused by the improvement of the sliding characteristics.
In the above-mentioned tool coated with the nitride of V, adhesion of the workpiece to the surface of the coating during use can be reduced, so that tool wear due to the mechanism can be suppressed. However, since the oxidation of the nitride of V further proceeds in the operating temperature range of approximately 300 ° C. or higher, it continues to contribute to the prevention of wear due to the formation of the oxide film. Helps wear.

In order to solve this problem, the above-described wear and tear can be achieved if V can be added to provide excellent sliding characteristics without impairing the characteristics of the hard film having excellent wear resistance and heat resistance. While introducing the suppression effect, this hard coating can be used continuously and stably even in the use region between warm temperatures.
In this case, Ti-based carbides and nitrides have a high hardness of HV3000 or higher, so they have excellent wear resistance, but their own oxidation temperature is low, so if the working surface temperature of the mold rises, the wear of the film Is easy to progress. On the other hand, since the AlCrSi nitride has a high hardness of HV3000 or higher, it has excellent wear resistance and excellent heat resistance as described above, so there is no problem of concern regarding Ti-based carbides and the like. . However, since the oxidation as seen in the nitride of V does not occur, it alone has poor sliding characteristics, and it is difficult to cope with local wear caused by adhesion of the workpiece.

  Therefore, the present invention provides a hard coating composed of a laminated structure of AlCrSi nitride and V nitride, so that the excellent sliding action of V nitride that generates an oxidation protective coating is wear resistant. The present inventors have found that AlCrSi nitride excellent in heat resistance can be imparted without impairing the characteristics. As a result, excellent wear resistance, heat resistance, and sliding characteristics are simultaneously achieved over the use range between cold and hot. The coated mold for plastic working according to the present invention having the above-mentioned properties in a well-balanced manner can suppress the occurrence of unevenness on the sliding surface of the film even in each temperature environment during use, and has low attack on the workpiece. Therefore, damage such as galling that occurs during sliding can be suppressed, and the life of the metal mold for plastic working can be improved.

The laminated film of AlCrSi nitride and V nitride employed in the present invention preferably has a nano-level thickness in order to effectively exhibit both characteristics of the individual nitride layers. The preferable film thickness in this case is such that the AlCrSi nitride film thickness is 100 nm or less and the V nitride film thickness is 100 nm or less.
In order to obtain sufficient sliding characteristics under the usage environment of the mold, the individual film thicknesses of the alternately stacked AlCrSi nitride and V nitride are as follows: V nitride is more than AlCrSi nitride Thickness is preferred. If the individual V nitrides are 1.5 times or more the AlCrSi nitrides, it is more preferable because V oxides that enhance the sliding characteristics are sufficiently generated. If the thickness of the nitride of V becomes too thick, the wear resistance may deteriorate depending on the use environment. The thickness of the nitride of V is not more than 4.0 times the thickness of the nitride of AlCrSi. It is preferable that

In the present invention, in the ratio adjustment of each constituent element, the metal composition component of the nitride of V is fixed by one element of V, so that the composition of the other AlCrSi nitride is adjusted to a predetermined one. Is the best. At this time, the ratio of each element type constituting the nitride of AlCrSi is Al _a Cr _b Si _c N (where a, b, and c indicate atomic ratios, and a + b + c = 1), , B, c ≠ 0 and a + b> 0.5. More preferably, a + b> 0.8. It is more preferable that the content of Al having excellent heat resistance is larger than that of Cr.

The film thickness of the hard film is 3 μm or more.
In press molding, since the force applied from the film surface is large, if the film is thinner than this, the film strength becomes poor and the film is easily damaged. In particular, in a high load environment, a large force is applied to the interface between the film and the base material, so the film is easily peeled off or damaged due to the difference in elastic deformation between the film and the base material. The influence of the film thickness on the thickness increases. Therefore, the film thickness is preferably 8 μm or more under a high load environment.
When the film thickness of the hard film becomes too thick, film peeling may easily occur, and the film thickness is preferably 20 μm or less. More preferably, it is 15 μm or less.

The surface roughness is Ra <0.2 μm, Rz <2.0 μm, and Rsk <0.
The surface of the hard film contains droplets, film defects, impurities, and the like, and is not suitable for use as a coating die for plastic working, so it needs to be smooth. In particular, when the film is thick, the surface roughness decreases due to accumulation of droplets and film defects, so the surface of the film needs to be smooth.
Under the sliding environment, the convex portion on the surface of the film is the starting point, and adhesion of the work material occurs, resulting in film peeling or wear. Therefore, it is most important to reduce the convex portions.
Therefore, only Ra and Rz, which are general surface roughnesses (ISO4287-1997), are insufficient to grasp the frequency of the convex portions, and in addition to Ra and Rz, control of Rsk is important. .
The surface roughness Rsk value (ISO4287-1997) is a parameter indicating the objectivity with respect to the center line of the amplitude distribution curve. For example, when the surface of the film has many concave portions, Rsk <0 is indicated, and when there are many convex portions, Rsk> 0 is indicated, and the frequency of the convex portions and the concave portions can be managed.
By controlling the surface roughness within the above range, in the coated tool including the V nitride layer, the V oxide formed on the surface of the base material under the use environment of the tool is very thinly formed. Therefore, the sliding characteristics are improved. When the workpiece is Fe-based, the sliding property can be improved by allowing the Fe oxide to be thinly and uniformly deposited on the entire V oxide on the V oxide.

  The above-mentioned hard coating employed by the present invention is not particularly limited with respect to the coating method. However, considering the heat effect on the base material of the coating mold for plastic working, the fatigue strength of the product, and the adhesion of the film, if the base material is die steel or high-speed steel, the temperature is lower than the tempering temperature. It is preferable to use a physical vapor deposition method (PVD method) such as an arc ion plating method or a sputtering method in which the film can be formed by a method and compressive stress remains in the film.

In the present invention, when a laminated film is formed by employing the PVD method, a V (vanadium) metal target can be used for the film formation. The V metal target has an advantage that it has good workability and is easy to manufacture. Therefore, AlCrSi nitride coating by physical vapor deposition method using an AlCrSi alloy target in a nitrogen atmosphere on the surface of a base material for a plastic mold, and physical vapor deposition using a V metal target in a nitrogen atmosphere. By repeating the coating of V nitride by the method, the coating die for plastic working of the present invention can be easily obtained.
More specifically, two or more types of targets each consisting of a simple V metal that is easy to manufacture and an AlCrSi alloy with adjusted components are prepared. And the PVD apparatus by which a target component is coat | covered alternately with the structure where a base material rotates in the center which a some target surrounds can be used. At this time, by adjusting the film forming atmosphere to nitrogen, when the surface of the rotating substrate passes the front surface of the AlCrSi alloy target, the nitride of AlCrSi is coated, and when passing the front surface of the V metal target, V The nitride can be coated.

  In order to achieve the surface roughness of the present invention, a polishing method after coating is important. With the conventional coating polishing methods such as polishing with abrasive paper and polishing with media made of resin and diamond particles, the surface roughness of Ra and Rz is smoothed, but the protrusions can be reliably reduced. It's not easy. Therefore, it is preferable to perform buffing using a diamond paste to reduce the number of protrusions and efficiently reduce the value of Rsk as well as Ra and Rz.

In the physical vapor deposition method using a target, since the coating rate differs depending on each component of the target, the individual film thickness can be controlled by controlling the current applied to the target. In the AlCrSi alloy target and the V metal target used in the present invention, the deposition rate of the V metal target is higher than that of the AlCrSi alloy target. The film thickness tends to be a thick film.
Therefore, in order to obtain sufficient lubrication characteristics under the tool use environment, in order to make the V nitride film thicker than the AlCrSi nitride film, the AlCrSi alloy target and the V metal are used. The ratio of the current supplied to the target is preferably 2.0 or less for the alloy target of AlCrSi / V metal target. In this case, the current supplied to the AlCrSi alloy target may be reduced, or the current supplied to the V metal target may be increased. More preferably, it is 1.5 or less.
In order to ensure a constant film formation rate, the current input to the target is preferably 80 A or more. If the current applied to the target becomes too large, the film formation is difficult to stabilize, so it is preferable to set the current to 160 A or less.

  Each of the hard coatings employed by the present invention has a compound structure of an AlCrSi nitride and a V nitride, and can exhibit its characteristics by setting an optimum film thickness and surface state. Therefore, even if AlCrSi nitride and part or all of V nitride take the form of carbonitride and oxycarbonitride, the effects of the present invention are exhibited.

In Example 1, the characteristics of the coating composition were evaluated with a ball-on-disk tester.
As the base material to be surface-treated, a disk-shaped test piece (diameter 20 mm × thickness 5 mm) of high-speed steel SKH51 specified by JIS was prepared. This was tempered to 64 HRC by tempering at 540 to 580 ° C. after quenching by cooling with nitrogen gas from heating and holding at 1180 ° C. in vacuum. These flat surfaces were mirror-polished to a surface roughness Ra of 0.016 μm, Rz of 0.016 μm, and Rsk−0.116, and then subjected to alkali ultrasonic cleaning.

  An arc ion plating method was used as the film forming means. The film formation is performed using a PVD apparatus having a structure in which the substrate rotates around the center surrounded by a plurality of targets, and the first and second targets shown in Table 1 are installed in the arc evaporation source. Then, the substrate was placed on a plate having a rotation mechanism on a jig table having a planetary mechanism in the chamber. The table and the plate on the table rotate independently of each other.

Next, heat degassing was performed in a vacuum at a temperature of 773 K and 1 × 10 ⁻³ Pa in an arc ion plating apparatus having a chamber volume of 1.4 m ³ (the insertion space for the processed product is 0.3 m ³ ). Thereafter, cleaning with Ar plasma was performed at a temperature of 723K. Then, nitrogen in the reaction gas was introduced into the apparatus, and arc discharge was generated on various targets. Under 723 K, the reaction gas pressure was 3 Pa, the table rotation speed was 5 rpm, and the base material during coating was -100 V. A bias voltage of Moreover, each film thickness ratio was adjusted by changing the electric current supplied to the V metal target.
Sample No. 1 to 5, the total film thickness of the hard coating is about 3.5 μm. 6 and 7, the film formation time was adjusted so that the total film thickness was about 8 μm. Table 1 shows the film forming conditions.

The coated surface was smoothed by buffing using a diamond paste having a particle diameter of 3 μm so that the sample had a predetermined surface roughness. And the surface roughness Ra, Rz, Rsk value of the film surface of each sample uses a stylus type roughness meter (SURFCOM 480A manufactured by Tokyo Seimitsu Co., Ltd.), an evaluation length of 4 mm, a measurement speed of 0.3 mm / s, The measurement was performed under the condition of a cut-off value of 0.8 mm.
The hardness of the coating surface was measured with a load of 150 kgf using a Vickers hardness tester (HM100 manufactured by Mitutoyo Corporation).
The average film thickness of the laminated film was measured by transmission electron microscope observation. The total film thickness was measured with an electron microscope. Table 2 shows each measurement result.

Sample No. 1 in which AlCrSi nitride layers and V nitride layers were alternately laminated. 1 to 3 had a hardness of HV3000 or higher. As the thickness of the V nitride layer increased, the hardness tended to decrease. Sample No. The V nitride of 5 had a hardness of HV2100, which was lower than that of the film containing the AlCrSi nitride.
The individual film thicknesses that were alternately stacked were obtained from the average of the film thicknesses of 10 adjacent layers in the measurement region.
Sample No. The individual film thicknesses of the laminated film 1 were about 3 nm for the AlCrSi nitride layer and about 6 nm for the V nitride layer. In FIG. 1 is a cross-sectional observation photograph of a film by a transmission electron microscope.
Sample No. No. 2 had a thickness of about 3 nm for the AlCrSi nitride layer and about 4.5 nm for the V nitride layer. Sample No. No. 3 had a thickness of about 3 nm for the AlCrSi nitride layer and about 3 nm for the V nitride layer. Sample No. No. 6 had an AlCrSi nitride layer of about 3 nm and a V nitride layer of about 6 nm.
The surface roughness of each sample was Ra <0.2 μm, Rz <2.0 μm, and Rsk <0.

  Sample No. About 1-7, the sliding characteristic when an other party material was set to JIS bearing steel SUJ2 was evaluated. As a test condition, a ball-on-disk tester (Tribometer manufactured by CSM Instruments) was used. The disk-shaped test piece was rotated at a speed of 150 mm / sec while pressing SUJ2 balls (diameter 6 mm) against the coating film with a load of 2 N in the atmosphere of 25 ° C. (normal temperature) to 400 ° C. The test distance was 100 m, and the friction coefficient was an average value of 10 m, 20 m, 30 m, 40 m, 50 m, 60 m, 70 m, 80 m, 90 m, and 100 m. Table 3 shows the wear coefficients of various films at various temperatures.

  Sample No. 2 having a laminated structure of AlCrSi nitride and V nitride. 1 to 3 and 6 are sample Nos. 1 and 2 which are nitrides of V. The coefficient of friction was as low as 5. Sample No. From the comparison of the stacking periods of 1 to 3, the friction coefficient increased as the ratio of the nitride layer of V decreased. Sample No. 1, which is a nitride of AlCrSi not containing nitride of V. Nos. 4 and 7 had higher wear coefficients than the examples of the present invention.

  Furthermore, about the film surface after the said test, the unevenness | corrugation of a film | membrane sliding part was measured on the conditions of 1.5 mm / s with a surface roughness meter (Surfcom 480A by Tokyo Seimitsu Co., Ltd.), The wear state of the film was evaluated. That is, when the surface unevenness value is plus (+), it is an attached form, and when it is minus (−), it means that the film is worn. Table 4 shows the measurement results of the wear state of the film. (FIG. 2 shows an enlarged overview photograph of the coating surface.) Table 5 shows the measurement results of the wear of the mating member φ6 SUJ2 ball.

Sample No. Since 1-3, 6 contains the nitride of AlCrSi which is excellent in abrasion resistance and heat resistance, the unevenness | corrugation of the sliding part decreased in each temperature environment. And since it contains the nitride layer of V which is excellent in sliding characteristics, the wear diameter of the counterpart material is almost the same in each temperature environment, and the aggressiveness to the counterpart material is reduced.
On the other hand, sample No. Nos. 4 and 7 did not contain a V nitride layer having excellent sliding performance, and as shown in Table 4, the counterpart material locally adhered to the surface of the film from a 25 ° C. test environment. As the test temperature increased, the amount of adhesion increased. Further, as the adhesion amount increased, the attacking property against the counterpart material also increased, and the wear diameter of the ball became extremely large as shown in Table 5.
Sample No. In No. 5, local adhesion did not occur, and the opponent aggression was also low as shown in Table 5. However, in the test environment of 200 ° C. or higher, the heat resistance of the film was low, the film was oxidized, and the amount of wear of the film increased as shown in Table 4.
Both the AlCrSiN film and the VN film have large variations in the amount of adhesion of the mating material on the sliding surface or the wear amount of the film at each test temperature, and the AlCrSi nitride and the V nitride of the composition of the present invention The sliding property was inferior compared to the laminated film.

Next, the actual durability was evaluated by a reciprocating frictional wear test in which the load applied to the hard coating was larger, assuming the usage environment of the actual mold.
For the substrate to be surface-treated, a square test of die steel SKD61 as defined in JIS, which was tempered to 45 HRC by tempering at 540 to 580 ° C. after quenching by cooling with nitrogen gas from heating at 1050 ° C. in vacuum. A piece (180 × 20 × 20) was prepared. These planes were mirror-polished to a surface roughness Ra of 0.016 μm, Rz of 0.016 μm, and Rsk−0.116, and then subjected to alkali ultrasonic cleaning.

As the film forming means, the same arc ion plating method as in Example 1 was used. Cleaning with Ar plasma was performed under the same conditions as in Example 1. Then, nitrogen in the reaction gas was introduced into the apparatus, and arc discharge was generated on various targets. Under 723 K, the reaction gas pressure was 3 Pa, the table rotation speed was 5 rpm, and the base material during coating was -100 V. No. 5 was applied to the sample No. 8-No. 19 was coated. The film thickness was changed by adjusting the coating time.
Then, sample b. The film surface of 8-17 was smoothed.
Sample No. Nos. 18 and 19 were smoothed with # 600 and # 1000 abrasive papers. The film forming conditions are shown in Table 6.

Sample No. whose surface was smoothed About 8-23, the surface roughness and the film thickness were measured by the same method as Example 1. And the frequency | count of damage and the friction coefficient were measured using the reciprocating friction wear test machine (Kyowa Giken Co., Ltd.). SKD61 (45HRC) of φ10 × 16 was used as the mating material to slide. The test was carried out at a measurement load of 200 kgf, a measurement speed of 150 mm / s, a sliding distance of 300 mm reciprocation, test conditions of room temperature and no lubrication.
The number of reciprocating friction and wear tests was up to 300 reciprocations, and the evaluation was performed by the number of times when the film was damaged and the substrate was exposed. The coefficient of friction was obtained by dividing the friction stress during sliding by the measured load.
Table 7 shows the results of various characteristic evaluations.

Among the examples of the present invention, Sample No. with a film thickness of 8 μm or more. In Nos. 8 to 14, no film damage occurred even in a reciprocating frictional wear test in which a high load was applied.
Sample No. of the present invention. 15 to 17 are sample Nos. Compared with 8-14, the film thickness was thin, and film damage occurred under a high load use environment.
Sample No. 18 shows the sample No. of the example of the present invention. 9 and Ra and Rz were similar, but Rsk> 0, and there were many convex portions on the coating surface. Therefore, although the film thickness was large, the sliding resistance was high, and the film damage occurred due to the generation of abrasion powder starting from the convex portion.
Sample No. In No. 19, since the surface roughness did not satisfy the range defined by the present invention and the film thickness was not within the preferred range, film damage occurred immediately.

  Since the coating surface for plastic working of the present invention has excellent wear resistance, heat resistance, and sliding properties on the surface of the coating, it can be applied to sliding parts constituting various machines.

Claims (8)

  A tool mold for plastic working in which a hard film is coated on the surface of a tool substrate, wherein the hard film is formed by alternately laminating AlCrSi nitride and V nitride, A coating die for plastic working excellent in sliding characteristics, characterized in that the film thickness is 3 μm or more, the surface roughness is Ra <0.2 μm, Rz <2.0 μm, and Rsk <0.   The coating die for plastic working excellent in sliding characteristics according to claim 1, wherein the film thickness of the hard coating is 8 µm or more.   3. The slide according to claim 1, wherein the thicknesses of the AlCrSi nitride and the V nitride stacked alternately are such that the V nitride is thicker than the AlCrSi nitride. Coated mold for plastic working with excellent dynamic characteristics.   4. The individual film thicknesses of the AlCrSi nitride and the V nitride stacked alternately are such that the V nitride is 1.5 times or more the AlCrSi nitride. Coating mold for plastic working with excellent sliding characteristics as described in 1.   5. The coating die for plastic working excellent in sliding characteristics according to claim 1, wherein the hard coating is coated by a physical vapor deposition method. The surface of the tool base is coated with AlCrSi nitride by physical vapor deposition using an AlCrSi alloy target in a nitrogen atmosphere, and V nitride is coated by physical vapor deposition using a V metal target in a nitrogen atmosphere. By repeating
Covering a hard film having a thickness of 3 μm or more in which AlCrSi nitride and V nitride are alternately laminated,
The surface of the hard coating is buffed with a diamond paste so that Ra <0.2 μm, Rz <2.0 μm, and Rsk <0. Production method.   7. The coating metal for plastic working having excellent sliding characteristics according to claim 6, wherein a hard film having a film thickness of 8 μm or more in which the AlCrSi nitride and the V nitride are alternately laminated is coated. Mold manufacturing method.   8. The sliding ratio according to claim 6, wherein the current ratio of the AlCrSi alloy target and the V metal target is 2.0 or less when the AlCrSi alloy target / V metal target is 2.0 or less. A manufacturing method of a coated mold for plastic working.