JP2006123079A - Surface coated member and surface coated cutting tool - Google Patents

Abstract

Provided is a long-life cutting tool having excellent fracture resistance and wear resistance by coating a surface with a hard coating layer having high strength.
In a surface-coated cutting tool 1 having a hard coating layer 3 including one or more titanium carbonitride layers 4 on the surface of a substrate 2, the surface of the surface-coated cutting tool 1 is hard with a hard sphere 8 in contact therewith. A wear mark 7 of a calotest that wears the hard coating layer 3 on a spherical curved surface so that the base 2 is exposed at the center of the wear mark 7 where the surface-coated cutting tool 1 is locally worn so that the ball 8 rotates while rolling. When observed, the titanium carbonitride layer 4 observed around the exposed substrate 2 existing at the center of the wear scar 7 has no cracks.
[Selection] Figure 1

Description

  The present invention relates to a surface coating member having a hard coating layer formed on the surface thereof, and in continuous cutting, welding wear, chipping, and chipping caused by cracks in the coating film can be prevented, and a large impact such as intermittent cutting is cut off. The present invention also relates to a surface-coated cutting tool having excellent chipping resistance and chipping resistance even when cutting such as a blade.

Conventionally, cutting tools widely used for metal cutting are titanium carbide (TiC) layers, titanium nitride (TiN) layers, titanium carbonitride (TiCN) layers on the surface of substrates such as cemented carbides, cermets, and ceramics. ) And a surface-coated cutting tool in which a plurality of hard coating layers such as an aluminum oxide (Al ₂ O ₃ ) layer are formed.

  In such surface-coated cutting tools, work materials such as carbon steel and cast iron are melted by the heat of cutting and adhere to the cutting edge, causing damage such as chipping of the cutting edge and film peeling when it falls off. There was a problem that the tool life could not be extended due to the occurrence of a large chipping or abnormal wear on the cutting edge as a trigger.

  Therefore, in Patent Document 1, a bonding layer having needle-like protrusions is interposed between the titanium carbonitride layer and the aluminum oxide layer to prevent the bonding layer from peeling off or cracking in the bonding layer itself. It describes what you can do.

In Patent Documents 2 and 3, the hard coating layer is proactively preliminarily generated with microcracks to suppress the progress of cracks, thereby reducing the occurrence of chipping and chipping, thereby reducing wear resistance and chipping resistance. A method of improving the above is described.
Japanese Patent Laid-Open No. 10-273778 JP-A-6-246513 Japanese Patent Laid-Open No. 13-267905

  However, since the difference in volume expansion between the titanium carbonitride layer and the aluminum oxide layer is not improved even by the method of changing the structure of the bonding layer as described in Patent Document 1, it still remains between the titanium carbonitride layer and the aluminum oxide layer. There was a problem that cracks occurred and further peeling occurred.

  Although the methods described in Patent Documents 2 and 3 can suppress chipping and chipping due to an impact during cutting, it is difficult to cut the workpiece under cutting conditions where the workpiece is easily welded to the tool. Abnormal wear and sudden defects due to chipping of the cutting edge due to the work material entering the cracks previously introduced into the titanium carbonitride layer, which is well suited to the work material, and promoting the welding of the work material Etc. occurred and the tool life was shortened.

  Accordingly, the present invention has been made to solve the above-mentioned problems, and its purpose is to suppress welding of the work material and to have excellent chipping resistance and chipping resistance without occurrence of chipping or film peeling. At the same time, it is an object to provide a long-life cutting tool having excellent wear resistance.

  As a result of studying the above-mentioned problems, the present inventor has provided the hard coating layer with titanium carbonitride that hardly generates cracks, thereby preventing welding of the work material and preventing chipping of the cutting edge and film peeling. I found out that I can do it.

  That is, the surface coating member of the present invention is a surface coating member having a hard coating layer including one or more titanium carbonitride layers on the surface of a substrate, and rotates hard balls to roll on the surface of the hard coating layer. Carrying out a so-called calotest that locally wears the hard sphere contact portion of the hard coating layer to form a sphere-curved wear mark so that the titanium carbonitride layer and the substrate of the hard coating layer are exposed, the wear When the trace is observed, the titanium carbonitride layer observed at the outer peripheral position of the exposed substrate existing at the center of the wear trace has no crack in the titanium carbonitride layer, in other words, the titanium carbonitride layer. Is formed continuously.

The hard coating layer includes at least a portion in which a titanium carbonitride layer, a bonding layer, and an aluminum oxide layer are sequentially stacked, and the film thickness of the titanium carbonitride layer is 3 μm ≦ t _T ≦ 13 μm. When the thickness satisfies 0.1 μm ≦ t _B ≦ 2 μm and the film thickness of the aluminum oxide layer satisfies 2 μm ≦ t _A ≦ 15 μm, the impact resistance of the entire hard coating layer is improved, and chipping and chipping as a whole tool are achieved. This is desirable because it is possible to prevent the damage and maintain high wear resistance.

  Further, the titanium carbonitride particles in the titanium carbonitride layer have a streak structure extending perpendicularly to the substrate surface, and the average crystal width w is 0.01 to 0.5 μm. This is desirable because it can increase the fracture resistance and chipping resistance of the crystal itself and can suppress the occurrence of cracks in the titanium carbonitride layer.

Further, when the titanium carbonitride layer is expressed as Ti (C _1-x N _x ), the titanium carbonitride layer has a composition in which x in the titanium carbonitride layer is greater than 0.5 and less than or equal to 0.70. This is desirable because the toughness of the layer can be improved to suppress the occurrence of cracks and the fracture resistance of the hard coating layer can be improved.

  Further, the ratio B / A of the average intensity A of titanium and the average intensity B of cobalt detected when the titanium carbonitride layer is analyzed by a wavelength dispersive X-ray microanalyzer (WDS: Wavelength Dispersive X-ray Spectroscopy). 0.01 to 0.1 is preferable because the toughness of the titanium carbonitride layer can be improved to suppress the occurrence of cracks and the fracture resistance of the hard coating layer can be improved.

  The ratio B / A of the average intensity A of titanium and the average intensity B of cobalt detected when the coupling layer is analyzed by the wavelength dispersive X-ray microanalyzer (WDS) is 0.01 to 0.1. Therefore, the stress difference due to the thermal expansion difference between the titanium carbonitride layer and the aluminum oxide layer can be relaxed, and delamination and chipping can be prevented.

  The surface covering member can be suitably used for structural materials that require wear resistance and fracture resistance, such as tools such as excavation tools, cutting tools, and blades, and wear-resistant materials such as molds and sliding members. However, particularly when used as a cutting tool, it exhibits excellent cutting performance capable of achieving both wear resistance and fracture resistance.

  According to the surface covering member of the present invention, in a surface covering member having a hard covering layer including one or more titanium carbonitride layers on the surface of the substrate, if a so-called calotest wear mark is observed, a partial portion of the hard covering layer is obtained. The distribution of wear resistance and fracture resistance can be evaluated. Specifically, by observing the wear scar, a carbonitriding layer is formed by continuously forming a titanium carbonitride layer observed around the exposed substrate present at the center of the wear scar. This is a guideline for indirectly confirming that the titanium layer itself is resistant to impact and that the residual stress at the interface with other layers is small and the occurrence of cracks between the layers is suppressed. In other words, the fact that no cracks are observed in the titanium carbonitride layer of the wear mark of Calotest means that cracks are also prevented from occurring in the hard coating layer during cutting, for example, the work material is welded. Even if it is cut under easy conditions, abnormal wear and chipping caused by cracks in the hard coating layer can be prevented and the life can be extended.

  FIG. 1 (a is an example of the present invention, (b) is a comparative example), hard coating of an example of a surface-coated cutting tool which is a preferred example of the surface-coated member of the present invention, which is a metal microscopic image of a wear mark of Calotest Description will be made based on FIG. 2 which is a scanning electron microscope (SEM) photograph of a fracture surface including a layer.

  According to FIGS. 1 and 2, a surface-coated cutting tool (hereinafter simply abbreviated as a tool) 1 includes tungsten carbide (WC) and, if desired, carbides, nitrides of Group 4a, 5a, and 6a metals in the periodic table. A cemented carbide obtained by bonding a hard phase composed of at least one selected from the group of carbonitrides with a binder phase composed of an iron group metal such as cobalt (Co) and / or nickel (Ni), a Ti-based cermet, Alternatively, the hard coating layer 3 is formed by chemical vapor deposition (CVD) on the surface of the substrate 2 made of ceramics such as silicon nitride, aluminum oxide, diamond, cubic boron nitride or the like.

  According to this embodiment, as shown in FIG. 2, the hard coating layer 3 has at least one titanium carbonitride (TiCN) layer 4. Further, FIG. 1 shows the wear scar 7 of the Calotest observed with a metal microscope or a scanning electron microscope (FIG. 1 is a metal micrograph), for example, at a magnification of 4 to 50 times (50 times in FIG. 1).

  Here, as shown in FIG. 3, the calotest defined as the evaluation item of the present invention is such that a hard sphere 8 made of metal or cemented carbide is brought into contact with the surface of the tool 1, that is, the surface of the hard coating layer 3. By rotating the support rod 9 that supports the hard sphere 8 in a state and rotating the hard sphere 8 while rolling, the tool 1 is locally worn, and the base 2 is placed at the center of the wear mark 7 as shown in FIG. The hard coating layer 3 is worn on the spherical curved surface so as to be exposed. Generally, the thickness of each layer is determined by observing the width of each layer of the hard coating layer 3 observed in the wear scar 7. This is an estimation method.

  According to the present invention, as the wear mark 7 of the above-mentioned calotest, the hard coating layer 3 is worn on the spherical curved surface so that the base body 2 is exposed at the center of the wear mark 7. It has been found that the properties and characteristics of the hard coating layer 3 can be evaluated by observing, for each layer, the wear and delamination of each layer of the hard coating layer 3 and the progress of cracks 5 included in the hard coating layer 3.

  According to the present invention, in the observation of the wear mark 7 of the Calotest as shown in FIG. 1, the titanium carbonitride layer observed at the outer peripheral position of the exposed substrate existing at the center of the wear mark 7 as shown in FIG. 4 is characterized by the absence of cracks, in other words, the titanium carbonitride layer 4 being formed continuously.

  Here, the titanium carbonitride layer 4 with the exposed wear marks 7 is continuously formed, which means that when the hard coating layer 3 is worn by the hard spheres 8, there are cracks 5 in the titanium carbonitride layer 4. In other words, the titanium carbonitride layer 4 is formed as a continuous structure without being divided by the crack 5.

  In addition, the crack in this invention refers to a crack whose width | variety which can be observed with a metal microscope or a scanning electron microscope (SEM) is 0.5 micrometer or more. Further, in the present invention, a plurality of titanium carbonitride layers may exist, but no cracks exist in each titanium carbonitride layer.

  Incidentally, since the crack 5 in the titanium carbonitride layer 4 may not be observed accurately if the size of the exposed portion of the substrate 2 is too large or too small, the substrate exposed in the wear scar 7 may be observed. It is preferable to adjust the wear conditions (time, type of hard sphere, abrasive, etc.) of the calotest so that the diameter of 2 is 0.1 to 0.6 times the diameter of the entire wear scar 7.

Further, as the configuration of the hard coating layer 3, at least the titanium carbonitride layer 4, the bonding layer 11, and the aluminum oxide layer 6 are sequentially laminated, so that the impact resistance of the entire hard coating layer 3 is improved. This is desirable in order to prevent chipping and breakage of the tool 1 as a whole and to maintain high wear resistance. In particular, the thickness t of the titanium carbonitride layer 4 is 3 μm ≦ t _T ≦ 13 μm, the thickness of the bonding layer is 0.1 μm ≦ t _B ≦ 2 μm, and the thickness of the aluminum oxide layer is 2 μm ≦ t _A ≦ 15 μm. Satisfaction is desirable because it increases the impact resistance of the entire hard coating layer 3, prevents chipping and breakage of the entire tool 1, and maintains high wear resistance.

  Moreover, it is difficult for cracks to occur in the titanium carbonitride layer 4 itself that the average crystal width w in the titanium carbonitride layer 4 is in the range of 0.01 to 0.5 μm, particularly 0.01 to 0.1 μm. This is desirable because it can improve the chipping resistance and chipping resistance of the hard coating layer 3.

  Here, as a method of measuring the average crystal width w of the titanium carbonitride particles composed of streak crystals in the present invention, a scanning electron micrograph observation is performed on the cross section including the hard coating layer 3, and the titanium carbonitride layer 4 A straight line parallel to the interface between the substrate 2 and the hard coating layer 3 is drawn at a height of ½ of the film thickness (see line segment α in FIG. 2), and the average value of the width of each particle on the line segment, That is, a value obtained by dividing the line segment length by the number of grain boundaries crossing the line segment is defined as the average crystal width w.

In addition, when the titanium carbonitride layer 4 is expressed as Ti (C _1-x N _x ), _{x in the} titanium carbonitride layer 4 is greater than 0.5 and less than or equal to 0.7, particularly 0.5 or more and 0.65 or less. This composition is desirable because it can improve the toughness of the titanium carbonitride layer 4 to suppress the occurrence of cracks and improve the fracture resistance of the hard coating layer 3.

  Furthermore, the ratio B / A of the average intensity A of titanium and the average intensity B of cobalt detected when the titanium carbonitride layer 4 is analyzed by a wavelength dispersive X-ray microanalyzer (WDS) is 0.01-0. By setting it within the range of 1, the toughness of the titanium carbonitride layer 4 can be improved, cracking can be suppressed, and the fracture resistance of the hard coating layer 3 can be improved. Moreover, since abrasion resistance will fall when there is too much cobalt amount in the titanium carbonitride layer 4, it is more preferable that said ratio B / A exists in the range of 0.01-0.05.

  Further, the ratio B / A of the average intensity A of titanium and the average intensity B of cobalt detected when the coupling layer 11 is analyzed by the wavelength dispersive X-ray microanalyzer (WDS) is 0.01 to 0.1. Therefore, the stress difference due to the thermal expansion difference between the titanium carbonitride layer 4 and the aluminum oxide layer 6 can be relaxed, and delamination and chipping can be prevented.

  When performing wavelength dispersion X-ray microanalyzer (WDS) analysis, mapping analysis is performed to measure cobalt and titanium for each part of the titanium carbonitride film 4 in one field of view, and the average value is calculated to calculate titanium carbonitride. The strength of cobalt and titanium in the layer 4 is used.

    Here, as described above, the hard coating layer 3 may be formed in the order of the titanium carbonitride layer 4, the bonding layer 11, and the aluminum oxide layer 6 in order to improve the wear resistance and oxidation resistance of the tool 1. This is desirable because it can improve the tool life.

  Further, the aluminum oxide layer 6 is excellent in that the crystal structure mainly composed of α structure, in other words, the peak having the highest peak intensity among the peaks of the aluminum oxide layer 6 in X-ray diffraction analysis is made of α-type aluminum oxide. High temperature hardness can be obtained and abrasion resistance can be improved, which is desirable. Moreover, when the layer thickness of the aluminum oxide layer 6 is 3 to 8 μm, the film can be prevented from peeling and the fracture resistance can be improved while maintaining the wear resistance, particularly the wear resistance against cast iron. desirable. Since the aluminum oxide layer 6 is a material that is difficult to weld to the work material, even if a small amount of cracks are present in the aluminum oxide layer 6, the welding resistance is not so much impaired.

  When the aluminum oxide layer 6 has an α-type crystal structure, a titanium carbonate (TiCO) layer or titanium oxynitride (TiNO) of 0.2 μm or less is provided between the titanium carbonitride layer 4 and the aluminum oxide layer 6. The α-type crystal structure can be stably grown by interposing the bonding layer 11 made of either a layer or a titanium carbonitride (TiCNO) layer.

  Moreover, as the hard coating layer 3, as the lowermost layer 10 existing between the substrate 2 and the titanium carbonitride layer 4, a titanium nitride (TiN) layer, a titanium carbide (TiC) layer, a titanium carbonitride oxide (TiCNO) layer In addition, by interposing at least one layer selected from the group consisting of a titanium carbonate (TiCO) layer and a titanium oxynitride (TiNO) layer, in particular, a titanium nitride layer, each component of the hard coating layer 3 is prevented from diffusing. It is possible to improve the interlayer adhesion, control the structure of the titanium carbonitride layer 4 and the aluminum oxide layer 6, the crystal structure, the adhesion, and the state of occurrence of cracks.

  Further, by forming a titanium nitride layer as the uppermost layer 12 of the hard coating layer 3, the tool 1 exhibits a gold color, so that it is easy to determine whether the tool 1 has been discolored and used, This is desirable because the progress of wear can be easily confirmed.

  In the above description, the example in which the surface covering member of the present invention is applied to a cutting tool has been described. However, the present invention is not limited to this example. For example, the wear resistance of an excavation tool, a mold, a sliding member, etc. It can be suitably used for structural materials that require wear resistance and fracture resistance such as materials.

(Production method)
In order to produce the above-mentioned surface-coated cutting tool, first, an inorganic powder such as metal carbide, nitride, carbonitride, oxide, etc. that can form the above-mentioned hard alloy by firing, metal powder, carbon powder, etc. Are added and mixed as appropriate, and then molded into a predetermined tool shape by a known molding method such as press molding, cast molding, extrusion molding, or cold isostatic pressing, and then fired in a vacuum or non-oxidizing atmosphere. By doing so, the base body 2 made of the hard alloy described above is produced.

  Here, cobalt can be diffused in the titanium carbonitride layer 4 by forming the hard coating layer 3 after polishing the surface of the substrate 2 after the thickness of 0.01 μm or less. In addition, the diffusion amount of cobalt from the base 2 can be optimized by forming a titanium nitride layer as the lowermost layer 10 to a thickness of 0.1 to 1 μm.

Thereafter, the titanium carbonitride layer 4 is formed on the surface of the lowermost layer 10. The film-forming conditions of the streaky titanium carbonitride layer 4 are, for example, 0.1% by volume to 10% by volume of titanium chloride (TiCl ₄ ) gas as a reaction gas composition by chemical vapor deposition (CVD) as a reaction gas composition, Nitrogen (N ₂ ) gas is 0 to 60% by volume, methane (CH ₄ ) gas is 0 to 0.1% by volume, acetonitrile (CH ₃ CN) gas is 0.1 to 3% by volume, and the remainder is hydrogen (H ₂ ) A mixed gas composed of a gas is prepared and introduced into the reaction chamber, and a film is formed in the chamber at 800 to 1100 ° C. and 5 to 85 kPa. The preferable range of the film forming temperature is preferably 860 to 880 ° C. in order to optimize the average crystal width of the titanium carbonitride layer 4.

  Here, if the ratio of acetonitrile gas in the reaction gas is less than 0.1% by volume among the above film forming conditions, it cannot be grown into a streaky titanium carbonitride crystal and becomes a granular crystal. Conversely, if the mixing ratio of acetonitrile gas in the reaction gas exceeds 3% by volume, the average crystal width of the titanium carbonitride crystal becomes large, and the ratio cannot be controlled.

  Further, after forming the streaky titanium carbonitride layer 4, the diffusion of cobalt from the base 2 can be promoted by setting the temperature in the chamber as high as 1050 to 1150 ° C.

Next, the bonding layer 11 is formed. When a titanium carbonitride (TiCNO) layer is formed as the bonding layer 11, the bonding layer 11 is adjusted while adjusting the structure of the titanium carbonitride layer 4 by controlling the film formation rate to be 0.3 to 1 μm / hr. The residual stress generated between the two can be reduced, and the residual stress generated at the interface of the aluminum oxide can be reduced without any cracks. An organization can be realized. As a specific film forming method, 0.1 to 1% by volume of titanium chloride (TiCl ₄ ) gas, 0.1 to 10% by volume of methane (CH ₄ ) gas, and 0.01% of carbon dioxide (CO ₂ ) gas are used. ˜1% by volume, nitrogen (N ₂ ) gas is 0-10% by volume, and the remaining gas mixture is hydrogen (H ₂ ) gas, which is sequentially adjusted and introduced into the reaction chamber. The atmosphere may be 1 to 6 kPa.

And according to this invention, the aluminum oxide layer 6 is formed into a film continuously. As a method of forming the aluminum oxide layer 6, ₃ to 20% by volume of aluminum chloride (AlCl ₃ ) gas, 0.5 to 3.5% by volume of hydrogen chloride (HCl) gas, and carbon dioxide (CO ₂ ) gas are used. Using a mixed gas composed of 0.01 to 5.0% by volume, 0 to 0.01% by volume of hydrogen sulfide (H ₂ S) gas, and the remainder consisting of hydrogen (H ₂ ) gas, 900 to 1100 ° C. and 5 to 10 kPa Is desirable.

Further, in order to form the titanium nitride (TiN) layer of the outermost surface layer 12, 0.1 to 10% by volume of titanium chloride (TiCl ₄ ) gas and 0 to 60% of nitrogen (N ₂ ) gas are used as the reaction gas composition. A mixed gas consisting of volume% and the remaining hydrogen (H ₂ ) gas is sequentially adjusted and introduced into the reaction chamber, and the inside of the chamber may be set to 800 to 1100 ° C. and 5 to 85 kPa.

  At this time, in addition to the above-described method, after the hard coating layer is formed by the chemical vapor deposition method, the cooling rate of the chamber up to 700 ° C. is controlled to 12 to 30 ° C./min. A structure | tissue can be controlled to the structure | tissue in which a crack is not observed by the said Calotest.

  The present invention is not limited to the above embodiment. For example, in the above description, the case where the chemical vapor deposition (CVD) method is used as the film forming method has been described. It may be formed by a physical vapor deposition (PVD) method.

  6% by mass of metallic cobalt (Co) powder with an average particle size of 1.2 μm and 0% of titanium carbide (TiC) powder with an average particle size of 2.0 μm with respect to tungsten carbide (WC) powder with an average particle size of 1.5 μm. .5% by mass, tantalum carbide (TaC) powder was added and mixed at a rate of 5% by mass, formed into a cutting tool shape (CNMA120204) by press molding, and then subjected to binder removal treatment in a vacuum of 0.01 Pa. A cemented carbide was produced by firing at 1500 ° C. for 1 hour. Further, the prepared cemented carbide was subjected to blade edge processing (Honing R) by brushing.

And for the above cemented carbide, sample No. 1 was formed by forming a hard coating layer composed of a multilayer film having the structure shown in Table 2 under the conditions shown in Table 1 on the various hard coating layers by the CVD method. 1 to 6 surface-coated cutting tools were produced. The chamber cooling rate to 700 ° C. after forming the hard coating layer 3 was 18 ° C./min. Sample No. Regarding 1 to 5, polishing was performed using a brush when forming the hard coating layer, and the outermost surface of the cemented carbide was removed. Sample No. For No. 6, a hard coating layer was formed on the burned skin surface after firing. Further, before forming TiCNO1 in the coating layer of Table 1 (Sample Nos. 1 to 4 and 6 of Table 1), after forming a streaky titanium carbonitride layer, the temperature in the chamber was once raised to 1050 ° C. Then, the temperature was further lowered to 1010 ° C. to form a TiCNO1 layer. Before forming the TiCNO2 film in the coating layer in Table 1 (Sample No. 5 in Table 1), after forming a streaked titanium carbonitride layer, the temperature inside the chamber was raised to 1010 ° C. to form a TiCNO2 layer. Filmed.

  About the obtained tool, the scanning electron microscope (SEM) photograph was taken about the arbitrary fractured surfaces including the cross section of a hard coating layer, or 5 places of grinding | polishing surfaces, and the structure | tissue of the titanium carbonitride (TiCN) layer was observed in each photograph. At this time, a line α as shown in FIG. 2 is drawn at a position half the total film thickness with respect to the film thickness of the titanium carbonitride layer, and the number of grain boundaries crossing each line segment is measured. Then, the value converted into the crystal width of the titanium carbonitride crystal was calculated, and the average value of the crystal width calculated for each of the five photographs was calculated as the average crystal width w. Moreover, the film thickness t of the titanium carbonitride layer was measured by the metal micrograph or SEM photograph.

  Furthermore, the crack state of the hard coating layer of the surface-coated cutting tool was observed with a metal microscope or SEM for the wear scar generated by the calotest test performed under the following conditions, and the titanium carbonitride layer observed with the calotest wear scar was observed. The presence or absence of cracks was measured.

Equipment: CSEM-CALOTEST manufactured by Nanotech
Steel balls 30 mm diameter spherical steel balls Diamond paste 1/4 MICRON
Cracks in a worn state so that the diameter of the substrate exposed in the wear scar is 0.1 to 0.6 times the diameter of the entire wear scar (0.3 to 0.7 mm in this measurement) Was observed. The results are shown in Table 2.

  Further, mapping analysis was performed with a wavelength dispersion type X-ray microanalyzer (WDS), the average intensity A of titanium and the average intensity B of cobalt in the titanium carbonitride layer were measured, and the ratio, B / A, was calculated. The results are shown in Table 2.

Further, the peak position of the titanium carbonitride layer was confirmed by X-ray diffraction analysis (XRD), and Ti (C _1-X , Tc) was determined from the peak positions of titanium nitride (TiN) and titanium carbide (TiC) defined by JCPDS. The value of X when expressed as N _X ) was estimated. The results are shown in Table 2.

  Then, using this cutting tool, a continuous cutting test and an intermittent cutting test were performed under the following conditions to evaluate the wear resistance and fracture resistance. The results are shown in Table 3.

(Continuous cutting test)
Work Material: Ductile Cast Iron Sleeve Material (FCD700)
Tool shape: CNMA120204
Cutting speed: 250 m / min Feed speed: 0.4 mm / rev
Cutting depth: 2mm
Cutting time: 20 minutes Others: Use of water-soluble cutting fluid Evaluation item: Observe the cutting edge with a microscope and measure the amount of flank wear and tip wear (intermittent test)
Work material: Ductile cast iron 4-slot sleeve material (FCD700)
Tool shape: CNMA120204
Cutting speed: 200 m / min Feeding speed: 0.3 to 0.5 mm / rev
Cutting depth: 2mm
Other: Use of water-soluble cutting fluid Evaluation item: Number of impacts leading to breakage
Observe the peeling state of the hard coating layer of the cutting edge with a microscope at the point of impact 1000 times

  From Tables 1-3, sample no. In 5 and 6, the particle size of the titanium carbonitride layer was large, or no diffusion of cobalt was observed in the titanium carbonitride layer, and both had cracks in the titanium carbonitride layer due to the polishing marks of the calotest. . Compared with 1-4, the wear resistance and fracture resistance were significantly reduced. Moreover, the welding of the work material was intense on the cutting edge portion of these tools.

  On the other hand, in accordance with the present invention, sample No. In 1-4, the hard coating layer did not peel off, had a long life both in continuous cutting and in intermittent cutting, and had excellent cutting performance in both chipping resistance and chipping resistance.

It is the metal microscope image ((a) this invention example, (b) conventional example) of the abrasion trace which carried out the calotest of the surface coating cutting tool which is a suitable example of the surface coating cutting member of this invention. It is a scanning electron microscope image about the surface coating layer area | region in the torn surface of the surface coating cutting tool of Fig.1 (a). It is a schematic diagram for demonstrating the testing method of a caro test.

Explanation of symbols

1: Surface coated cutting tool 2: Substrate 3: Hard coating layer 4: Titanium carbonitride (TiCN) layer 5: Crack 6: Aluminum oxide (Al ₂ O ₃ ) layer 7: Wear scar 8: Hard ball 9: Support rod 10 : Bottom layer 11: intermediate layer 12: top layer w: average crystal width t of titanium carbonitride layer: film thickness of titanium carbonitride layer

Claims (8)

In the surface coating member having a hard coating layer including one or more titanium carbonitride layers on the surface of the substrate, the hard sphere contact portion of the hard coating layer is rotated by rolling the hard sphere on the surface of the hard coating layer. It is made to wear locally to form a spherical curved wear scar so as to expose the titanium carbonitride layer and substrate of the hard coating layer, and there is no crack in the titanium carbonitride layer where the wear scar is exposed. A surface covering member characterized by the above. The hard coating layer includes at least a portion in which a titanium carbonitride layer, a bonding layer, and an aluminum oxide layer are sequentially laminated. The film thickness of the titanium carbonitride layer is 3 μm ≦ t _T ≦ 13 μm, and the film thickness of the bonding layer is The surface covering member according to claim 1, wherein 0.1 μm ≦ t _B ≦ 2 μm, and the film thickness of the aluminum oxide layer is 2 μm ≦ t _A ≦ 15 μm. 2. The titanium carbonitride particles in the titanium carbonitride layer have a streak structure extending perpendicularly to the substrate surface, and the average crystal width w is 0.01 to 0.5 μm. Or the surface covering member of 2. When the titanium carbonitride layer is expressed as Ti (C1 _-xNx ), _{x in the} titanium carbonitride layer has a composition of more than 0.5 and 0.7 or less. 4. The surface covering member according to any one of 3. When the titanium carbonitride layer is analyzed by a wavelength dispersive X-ray microanalyzer (WDS), the ratio B / A of the average intensity A of titanium and the average intensity B of cobalt is 0.01 to 0.1. The surface covering member according to claim 1, wherein the surface covering member is provided. The ratio B / A of the average intensity A of titanium and the average intensity B of cobalt detected when the coupling layer is analyzed by the wavelength dispersive X-ray microanalyzer (WDS) is 0.01 to 0.1. The surface covering member according to claim 5. In the surface coating member having a hard coating layer including one or more titanium carbonitride layers on the surface of the substrate, the hard coating layer includes a portion in which at least a titanium carbonitride layer, a bonding layer, and an aluminum oxide layer are sequentially laminated, The film thickness of the titanium carbonitride layer is 3 μm ≦ t _T ≦ 13 μm, the film thickness of the bonding layer is 0.1 μm ≦ t _B ≦ 2 μm, and the film thickness of the aluminum oxide layer is 2 μm ≦ t _A ≦ 15 μm. The surface covering member characterized. A surface-coated cutting tool comprising the surface-coated member according to claim 1.

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