Coated tool

Information

  • Patent Grant
  • 10265775
  • Patent Number
    10,265,775
  • Date Filed
    Friday, March 27, 2015
    9 years ago
  • Date Issued
    Tuesday, April 23, 2019
    5 years ago
Abstract
A coated tool includes a substrate and a coating layer having a plurality of first laminated structures alternated with a plurality of second laminated structures. Each of the first laminated structures and each of the second laminated structures contains at least two kinds of layers having different composition and alternately laminated twice or more. An average thickness of the layers contained in the first laminated structure is between 60 nm and 500 nm, while an average thickness of the layers contained in the second laminated structure is between 2 nm and 60 nm. Each of the layers within the laminated structures include at least one metal element and at least one non-metal element selected from among carbon, nitrogen, oxygen and boron. An average thickness of the first laminated structure and/or the second laminated structure decreases with increasing distance from the substrate.
Description
RELATED APPLICATIONS

This is a 371 US National Phase of International Patent Application No. PCT/JP2015/059553 filed Mar. 27, 2015, and published as WO 2015/147241A1 on Oct. 1, 2015, which claims priority to JP 2014-064910, filed Mar. 27, 2014. The contents of the aforementioned applications are incorporated by reference in their entirety.


TECHNICAL FIELD

The present invention relates to a coated tool.


BACKGROUND ART

In recent years, cutting with high efficiency has been highly demanded. Accompanying with heightening of this demand, a cutting tool having a longer tool life than that of the conventional ones has been required. Thus, as characteristics required for the tool materials, it is important to improve characteristics relating to lifetime of a cutting tool. For example, it is more important to improve wear resistance and fracture resistance of the cutting tool. To improve these characteristics, a coated tool wherein alternately laminated films in which coating films are alternately laminated are formed on a substrate has been used.


To improve characteristics of such alternately laminated films, various techniques have been proposed. In Patent document 1, for example, a cutting tool in which a specific metal element or a compound thereof, and a specific alloy compound are laminated onto a surface of a base material with laminating cycles of 0.4 nm to 50 nm has been proposed. It has been disclosed that the cutting tool shows excellent wear resistance.


In Patent document 2, a cutting tool in which a first layer and a second layer are alternately laminated on a substrate so that these layers become 4 layers or more has been proposed. The first layer contains a complex nitride represented by the compositional formula of (Ti1-XAlX)N (X: 0.30 to 0.70 in an atomic ratio). The second layer contains an aluminum oxide phase and a titanium nitride phase. A ratio of the aluminum oxide phase in the second layer is 35 to 65% by mass based on the total of the aluminum oxide phase and the titanium nitride phase. Average thicknesses of the first layer and the second layer are each 0.2 to 1 μm. An average thickness of the first layer and the second layer in total is 2 to 10 μm. It has been disclosed that the cutting tool has excellent wear resistance.


In Patent document 3, a coated tool containing a first laminated structure and a second laminated structure has been proposed. The first laminated structure has a structure in which two or more layers having different compositions are periodically laminated. The average thickness of the respective layers contained in the first laminated structure is 60 nm or more and 500 nm or less. The second laminated structure has a structure in which two or more layers having different compositions are periodically laminated. The average thickness of the respective layers contained in the second laminated structure is 2 nm or more and less than 60 nm.


PRIOR ART DOCUMENT
Patent Document



  • Patent document 1: JP Hei.7-205361A

  • Patent document 2: JP 2003-200306A

  • Patent document 3: WO 2014/025057A



SUMMARY OF THE INVENTION
Problems to be Solved by the Invention

In recent years, high speed, high feeding and deep cutting in a cutting process becomes more remarkable. Thus, fracture of the tool has been frequently generated. For example, due to the load applied to the cutting edge during the processing, cracks are generated at the surface of the tool. By propagating the cracks to the substrate, fracture of the tool is generated. In addition, if a temperature of the cutting edge is rapidly raised or lowered, cracks are generated at the substrate. By propagating the cracks to the coating layer, fracture of the tool is generated.


According to such a background, the cutting tool disclosed in the above-mentioned Patent document 1 has high wear resistance, but has a problem that fracture of the tool is likely generated. The cutting tool disclosed in Patent document 2 has a problem that wear resistance is poor since hardness of the film is insufficient. The cutting tool disclosed in Patent document 3 cannot fulfil the required properties since fracture resistance is insufficient.


The present invention has been done to solve these problems. An object of the present invention is to improve fracture resistance without lowering wear resistance of a coated tool. In addition, an object of the present invention is to provide a coated tool having long tool life.


Means to Solve the Problems

The present inventors have intensively researched on elongation of tool life of a coated tool. The present inventors have accomplished improvement in fracture resistance without lowering wear resistance of the coated tool by improving a constitution of the coating layer. As a result, tool life of the coated tool could be elongated.


That is, the summary of the present invention is as follows.


(1) A coated tool which comprises a substrate, and


a coating layer formed onto a surface of the substrate,


wherein the coating layer contains a first laminated structure and a second laminated structure,


the first laminated structure and the second laminated structure are laminated alternately and continuously twice or more,


the first laminated structure contains at least two kinds of layers having different compositions, and the two kinds of the layers are alternately laminated twice or more,


an average layer thickness of the layers contained in the first laminated structure is 60 nm or more and 500 nm or less,


the second laminated structure contains at least two kinds of layers having different compositions, and the two kinds of the layers are alternately laminated twice or more,


an average layer thickness of the layers contained in the second laminated structure is 2 nm or more and less than 60 nm,


the layers contained in the first laminated structure and the second laminated structure contain a compound which contains at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi, and at least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron, an average thickness(es) of the first laminated structure and/or the second laminated structure is/are continuously or stepwisely reduced from the substrate side toward a surface side of the coating layer.


(2) The coated tool according to (1), wherein an average thickness of the first laminated structure is 0.2 μm or more and 6 μm or less.


(3) The coated tool according to (1) or (2), wherein an average thickness of the second laminated structure is 0.02 μm or more and 6 μm or less.


(4) The coated tool according to any one of (1) to (3), wherein an average thickness of the whole coating layer is 0.22 μm or more and 12 μm or less.


(5) The coated tool according to any one of (1) to (4), wherein when an average thickness of the first laminated structure nearest to the surface of the coating layer is made TA1, and an average thickness of the first laminated structure nearest to the substrate is made TB1, then a ratio of TA1 to TB1 is 5% or more and 50% or less.


(6) The coated tool according to any one of (1) to (5), wherein when an average thickness of the second laminated structure nearest to the surface of the coating layer is made TA2, and an average thickness of the second laminated structure nearest to the substrate is made TB2, then a ratio of TA2 to TB2 is 5% or more and 50% or less.


(7) The coated tool according to any one of (1) to (6), wherein when an average thickness of the layers contained in the first laminated structure nearest to the surface of the coating layer is made TC1, and an average thickness of the layers contained in the first laminated structure nearest to the substrate is made TD1, then a ratio of TC1 to TD1 is 12% or more and 70% or less.


(8) The coated tool according to any one of (1) to (7), wherein when an average thickness of the layers contained in the second laminated structure nearest to the surface of the coating layer is made TC2, and an average thickness of the layers contained in the second laminated structure nearest to the substrate is made TD2, then a ratio of TC2 to TD2 is 5% or more and 70% or less.


(9) The coated tool according to any one of (1) to (8), wherein the layers contained in the first laminated structure and the layers contained in the second laminated structure contain a compound comprising at least two metal elements selected from the group consisting of Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y, and at least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron.


Effects of the Invention

The coated tool of the present invention is excellent in wear resistance and fracture resistance, so that it can accomplish the effect that tool life can be elongated than those of the conventional ones.





BRIEF DESCRIPTION OF THE DRAWING


FIG. 1 is an example of a schematic drawing of a cross-sectional structure of the coated tool of the present invention.





EMBODIMENT TO CARRY OUT THE INVENTION

The coated tool of the present invention comprises a substrate and a coating layer formed onto a surface of the substrate. The substrate of the present invention may be any material so long as it is used as a substrate of the coated tool. The substrate of the present invention is not particularly limited and may be, for example, a cemented carbide, cermet, ceramics, a cubic boron nitride sintered body, a diamond sintered body and high-speed steel. Among these materials, a cemented carbide is preferred. This is because the cemented carbide is excellent in wear resistance and fracture resistance.


In the coated tool of the present invention, an average thickness of the whole coating layer is preferably 0.22 to 12 μm. If the average thickness of the coating layer is less than 0.22 μm, wear resistance of the coated tool tends to be lowered. If the average thickness of the coating layer exceeds 12 μm, fracture resistance of the coated tool tends to be lowered. The average thickness of the whole coating layer is further preferably 1.0 to 8.0 μm.


In the coated tool of the present invention, the coating layer contains a specific first laminated structure and second laminated structure. The respective layers contained in the first laminated structure and the second laminated structure contain a compound comprising at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi, and at least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron. The coated tool of the present invention is excellent in wear resistance.


The layers contained in the first laminated structure and the second laminated structure more preferably contain a compound comprising at least two kinds of metal elements selected from the group consisting of Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y, and at least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron. This is because such a compound has a property of being hard. The compound contained in the layer constituting the first laminated structure may be specifically (Al0.50Ti0.50)N, (Al0.60Ti0.40)N, (Al0.67Ti0.33)N, (Al0.67Ti0.33)CN, (Al0.45Ti0.45Si0.10)N, (Al0.45Ti0.45Y0.10)N, (Al0.50Ti0.30Cr0.20)N, (Al0.50Ti0.45Nb0.05)N, (Al0.50Ti0.45Ta0.05)N, (Al0.50Ti0.45W0.05)N, (Ti0.90Si10)N, (Al0.50Cr0.50)N, etc.


The metal element(s) contained in the layer constituting the first laminated structure is/are preferably the same as the metal element(s) contained in the other layers constituting the first laminated structure. That is, a plurality of the layers constituting the first laminated structure are preferably constituted by the same kinds of the metal elements. In addition, it is preferred that an absolute value of the difference between a ratio of the specific metal elements contained in a layer constituting the first laminated structure and a ratio of the specific metal elements contained in the other layer constituting the first laminated structure adjacent to the above layer is 5 atomic % or more. “A ratio of the specific metal elements” herein mentioned means a ratio (atomic %) of the number of the atoms of the specific metal elements contained in the layer based on the number of atoms of the whole metal elements contained in the layer.


If the first laminated structure employs such a constitution, crystal lattice becomes inconsistent at the boundary surface between the layers without lowering adhesiveness between a layer constituting the first laminated structure and a layer adjacent to the layer. Therefore, cracks are likely propagated to the direction parallel to the boundary surface of the layers constituting the first laminated structure, whereby propagation of the cracks to the substrate can be effectively suppressed.


With regard to the above-mentioned “absolute value of the difference between a ratio of the specific metal elements contained in a layer and a ratio of the specific metal elements contained in the other layers adjacent to the above layer is 5 atomic % or more”, it is explained in more detail.


For example, when the first laminated structure is constituted by an (Al0.55Ti0.45)N layer and an (Al0.67Ti0.33)N layer, the kinds of the metal elements contained in the two layers are the same. This is because the two layers both contain Al and Ti. In this case, the number of the atoms of Al contained in the (Al0.55Ti0.45)N layer is 55 atomic % based on the number of the atoms of the whole metal elements. The number of the atoms of Al contained in the (Al0.67Ti0.33)N layer is 67 atomic % based on the number of the atoms of the whole metal elements. The difference in the ratios of the numbers of the atoms of Al in these two layers is 12 atomic %. Accordingly, in this case, the above-mentioned condition that “the absolute value of the difference is 5 atomic % or more” is satisfied.


For example, when the first laminated structure is constituted by a (Al0.49Ti0.39Cr0.12)N layer and a (Al0.56Ti0.36Cr0.08)N layer, the kinds of the metal elements contained in the two layers are the same. This is because the two layers both contain Al, Ti and Cr. In this case, the difference in the ratios of the numbers of the atoms of Ti contained in the two layers is 3 atomic %. The difference in the ratios of the numbers of the atoms of Cr contained in the two layers is 4 atomic %. These values are each less than 5 atomic %. However, even in this case, the difference in the ratios of the numbers of the atoms of Al contained in the two layers is 7 atomic %, so that the above-mentioned condition that “an absolute value of the difference is 5 atomic % or more” is satisfied.


In the present specification, when the nitride is shown as (MaLb)N, it means that an atomic ratio of the M element based on the whole metal elements is a, and an atomic ratio of the L element based on the whole metal elements is b. For example, (Al0.55Ti0.45)N means that an atomic ratio of the Al element based on the whole metal elements is 0.55, and an atomic ratio of the Ti element based on the whole metal elements is 0.45. That is, (Al0.55Ti0.45)N shows that an amount of the Al element based on the whole metal element is 55 atomic %, and an amount of the Ti element based on the whole metal element is 45 atomic %.


The metal element(s) contained in the layers constituting the second laminated structure is/are preferably the same as the metal element(s) contained in the other layers constituting the second laminated structure. That is, a plurality of the layers constituting the second laminated structure are preferably constituted by the same kinds of the metal elements. In addition, it is preferred that an absolute value of the difference between a ratio of the specific metal elements contained in a layer constituting the second laminated structure and a ratio of the specific metal elements contained in the other layer constituting the second laminated structure adjacent to the above layer is 5 atomic % or more. “A ratio of the specific metal elements” herein mentioned means a ratio (atomic %) of the number of the atoms of the specific metal elements contained in the layer based on the number of atoms of the whole metal elements contained in the layer.


If the second laminated structure employs such a constitution, crystal lattice becomes inconsistent at the boundary surface between the layers without lowering adhesiveness between a layer constituting the second laminated structure and a layer adjacent to the layer. Therefore, cracks are likely propagated to the direction parallel to the boundary surface of the layers constituting the second laminated structure, whereby propagation of the cracks to the substrate can be effectively suppressed. The meaning of the above-mentioned “absolute value of the difference between a ratio of the specific metal elements contained in a layer and a ratio of the specific metal elements contained in the other layers adjacent to the above layer is 5 atomic % or more” is the same as those explained in the above first laminated structure.


As the other embodiments of the coated tool of the present invention, it is preferred that one or more kinds of the metal elements contained in a layer constituting the first laminated structure is different from the metal elements contained in the other layer constituting the first laminated structure adjacent to the above layer. If one or more kinds of the metal elements is/are different, crystal lattice becomes inconsistent at the boundary surface between the layers, and cracks are likely propagated to the direction parallel to the boundary surface of the layers, whereby propagation of the cracks to the substrate can be effectively suppressed.


For example, when the first laminated structure is constituted by an (Al0.50Ti0.50)N layer and an (Al0.50Ti0.30Cr0.20)N layer, and the metal elements contained in the two layers are compared to each other, the above condition is satisfied. This is because the two layers contains Al and Ti, but Cr is contained in one layer alone.


For example, when the first laminated structure is constituted by an (Al0.50Cr0.50)N layer and an (Al0.67Ti0.33)N layer, and the metal elements contained in the two layers are compared to each other, the above condition is satisfied. This is because the two layers contains Al, but Cr and Ti are respectively contained in one layer alone.


Similarly, in the coated tool of the present invention, it is preferred that one or more kinds of the metal elements contained in a layer constituting the second laminated structure is different from the metal elements contained in the other layers constituting the second laminated structure adjacent to the above layer. If one or more kinds of the metal elements is/are different, crystal lattice becomes inconsistent at the boundary surface between the layers, and cracks are likely propagated to the direction parallel to the boundary surface of the layers, whereby propagation of the cracks to the substrate can be effectively suppressed.


The coated tool of the present invention contains a coating layer. The coating layer contains a first laminated structure. The first laminated structure contains two or more layers comprising the above-mentioned compound. The average thickness of the respective layers contained in the first laminated structure is 60 nm or more and 500 nm or less. Two or more layers contained in the first laminated structure are periodically laminated. The periodically laminated structure contains at least two kinds of layers having different compositions. These two kinds of layers are preferably laminated alternately twice or more. When two kinds of layers having different compositions are laminated alternately twice or more, propagation of the cracks is suppressed, so that fracture resistance of the coated tool is further improved.


In the present invention, the minimum unit of the thickness in which lamination of the layers is repeated is called as “laminating cycle”.



FIG. 1 is an example of a schematic drawing of a cross-sectional structure of the coated tool of the present invention. In the following, the laminating cycle is explained by referring to FIG. 1.


For example, Layer A1, Layer B1, Layer C1 and Layer D1 which have different compositions are repeatedly laminated from the substrate (1) toward the surface of the coating layer (2). More specifically, these layers are laminated in the order of Layer A1→Layer B1→Layer C1→Layer D1→Layer A1→Layer B 1→Layer C1→Layer D1→ . . . . In this case, the total thickness from Layer A1 to Layer D1 is a “laminating cycle”.


For example, Layer A1 and Layer B1 which have different compositions are repeatedly laminated from the substrate (1) toward the surface of the coating layer (2). More specifically, these layers are laminated in the order of Layer A1→Layer B1→Layer A2→Layer B1→Layer A1→Layer B1→ . . . . In this case, the total of the thickness of Layer A1 and the thickness of Layer B1 is a “laminating cycle”.


To form the first laminated structure, at least two kinds of layers having different compositions are periodically laminated. The average thickness of the respective layers is 60 nm or more and 500 nm or less. By being formed the first laminated structure as mentioned above, the following effects can be obtained.


Cracks generated at the surface of the coating layer during the use of the coated tool reach to the first laminated structure. The cracks reached to the first laminated structure propagate to the direction parallel to the boundary surface of the layers having different compositions. This brings an effect that the propagation of the cracks to the substrate can be prevented. Such an effect can be more heightened by alternately laminating two layers having different compositions twice or more. More specifically, it is preferred that Layer A1 and Layer B1 having different compositions are alternately laminated twice or more from the substrate toward the surface of the coating layer. That is, the first laminated structure preferably contains an alternately laminated structure of Layer A1→Layer B1→Layer A1→Layer B1→ . . . .


If the average thickness of the respective layers contained in the first laminated structure is less than 60 nm, propagation of the cracks to the substrate cannot sufficiently be prevented. On the other hand, if the average thickness of the respective layers exceeds 500 nm, fracture resistance of the coated tool is lowered. Therefore, the average thickness of the respective layers contained in the first laminated structure is 60 nm or more and 500 nm or less. The average thickness of the respective layers contained in the first laminated structure is preferably 60 nm or more and 250 nm or less.


If the average thickness of the first laminated structure is less than 0.2 μm, a number (a number of repeated times) of periodically laminating the layers having different compositions becomes small. In this case, the effect of suppressing propagation of cracks to the substrate is lowered. On the other hand, if the average thickness of the first laminated structure exceeds 6 μm, residual compressive stress of the whole coating layer becomes high. As a result, peeling or fracture of the coating layer likely occurs, whereby fracture resistance of the coated tool is lowered. Accordingly, the average thickness of the first laminated structure is preferably 0.2 to 6 μm.


The coated tool of the present invention contains a coating layer. The coating layer contains a second laminated structure. The second laminated structure contains two or more layers comprising the above-mentioned compound. The average thickness of the respective layers contained in the second laminated structure is 2 nm or more and less than 60 nm. Two or more layers contained in the second laminated structure are periodically laminated. The periodically laminated structure contains at least two kinds of layers having different compositions. These two kinds of layers are preferably laminated alternately twice or more. When two kinds of layers having different compositions are laminated alternately twice or more, hardness of the second laminated structure is high, so that wear resistance of the coated tool is further improved.


In the second laminated structure, the minimum unit of the thickness in which lamination of the layers is repeated is called as “laminating cycle”.


For example, in FIG. 1, Layer A2, Layer B2, Layer C2 and Layer D2 which have different compositions are repeatedly laminated from the substrate (1) toward the surface of the coating layer (2). More specifically, these layers are laminated in the order of Layer A2→Layer B2→Layer C2→Layer D2→Layer A2→Layer B2→Layer C2→Layer D2→ . . . . In this case, the total thickness from Layer A2 to Layer D2 is a “laminating cycle”.


For example, Layer A2 and Layer B2 which have different compositions are repeatedly laminated from the substrate (1) toward the surface of the coating layer (2). More specifically, these layers are laminated in the order of Layer A2→Layer B2→Layer A2→Layer B2→Layer A2→Layer B2→ . . . . In this case, total of the thickness of Layer A2 and the thickness of Layer B2 is a “laminating cycle”.


To form the second laminated structure, at least two kinds of layers having different compositions are periodically laminated. The average thickness of the respective layers is 2 nm or more and less than 60 nm. By the second laminated structure being thus formed, hardness of the second laminated structure becomes high whereby wear resistance of the coated tool improves. Such an effect can be more heightened by alternately laminating two layers having different compositions twice or more. More specifically, it is preferred that Layer A2 and Layer B2 having different compositions are alternately laminated twice or more from the substrate toward the surface of the coating layer. That is, the second laminated structure preferably contains an alternately laminated structure of Layer A2→Layer B2→Layer A2→Layer B2→ . . . .


If the average thickness of the respective layers contained in the second laminated structure is less than 2 nm, it is difficult to form a layer having a uniform thickness. If the average thickness of the respective layers contained in the second laminated structure is 60 nm or more, hardness of the second laminated structure is lowered, so that wear resistance of the coated tool is lowered. Further, in this case, difference between the thickness of the second laminated structure and the thickness of the first laminated structure becomes small. As a result, cracks to the direction parallel to the boundary surface of the first laminated structure and the second laminated structure do not propagate, whereby propagation of the cracks to the substrate cannot sufficiently be suppressed. Therefore, the average thickness of the respective layers contained in the second laminated structure is 2 nm or more and less than 60 nm. The average thickness of the respective layers contained in the second laminated structure is preferably 5 nm or more and 30 nm or less.


If the average thickness of the second laminated structure is less than 0.02 μm, a number (a number of repeated times) of periodically laminating the layers having different compositions becomes small. In this case, the effect of improving hardness of the second laminated structure cannot be obtained. On the other hand, if the average thickness of the second laminated structure exceeds 6 μm, residual compressive stress of the second laminated structure becomes high. As a result, peeling or fracture of the coating layer likely occurs, whereby fracture resistance of the coated tool is lowered. Accordingly, the average thickness of the second laminated structure is preferably 0.02 to 6 μm.


The coated tool of the present invention contains a coating layer. The coating layer contains the first laminated structure excellent in fracture resistance and the second laminated structure excellent in wear resistance. Accordingly, the coated tool of the present invention is excellent in fracture resistance and wear resistance. The coating layer may contain an upper layer. The upper layer is a layer positioned at the surface side of the coating layer than the first laminated structure and the second laminated structure. The surface side of the coating layer means a side of the coating layer positioned opposite to the substrate. In addition, the coating layer may contain a lower layer. The lower layer is a layer positioned at the substrate side than the first laminated structure and the second laminated structure.


Constitutions of the upper layer and the lower layer are not particularly limited. The upper layer and the lower layer preferably contain at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi. Further, the upper layer and the lower layer preferably contain a compound comprising at least one kind of a metal element selected from these metal elements and at least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron. Constitutions of the upper layer and the lower layer are preferably a monolayer or a non-periodical multi-layer. When the upper layer and the lower layer have such a constitution, wear resistance of the upper layer and the lower layer is improved.


The first laminated structure and the second laminated structure are preferably laminated two or more alternately and continuously. If the first laminated structure and the second laminated structure are alternately laminated, cracks are likely propagated to the direction parallel to the boundary surface of the first laminated structure and the second laminated structure. As a result, propagation of the cracks to the substrate can be suppressed, whereby fracture resistance of the coated tool is improved.


Positional relationship of the first laminated structure and the second laminated structure is not particularly limited. The positional relationship of the first laminated structure and the second laminated structure are, for example, any of the following (1) to (4).


(1) The first laminated structure is nearest to the substrate, and the second laminated structure is nearest to the surface of the coating layer.


(2) The second laminated structure is nearest to the substrate, and the first laminated structure is nearest to the surface of the coating layer.


(3) The first laminated structure is nearest to the substrate, and is nearest to the surface of the coating layer.


(4) The second laminated structure is nearest to the substrate, and is nearest to the surface of the coating layer.


In the above-mentioned (1) to (4), “the surface of the coating layer” means a surface of the coating layer positioned opposite to the substrate.


Among the above-mentioned positional relationship, (1) is preferred. When the positional relationship of the first laminated structure and the second laminated structure is the above-mentioned (1), residual compressive stress of the first laminated structure is lower than residual compressive stress of the second laminated structure, so that peeling resistance of the coating layer tends to be improved.


The average thickness of the first laminated structure and/or the second laminated structure is continuously or stepwisely reduced from the substrate side toward the surface side of the coating layer. This is because fracture resistance can be improved without lowering wear resistance of the coating layer.


At the surface side of the coating layer, the average thickness(es) of the first laminated structure and/or the second laminated structure is/are decreased, so that a distance between boundary surfaces of the first laminated structures and the second laminated structures becomes short. When the distance between boundary surfaces of the first laminated structure and the second laminated structure becomes short, cracks are likely propagated to the direction parallel to the boundary surface of the first laminated structure and the second laminated structure. As a result, an effect of suppressing propagation of the cracks to the substrate can be obtained as well as fracture resistance is improved. Therefore, if the average thickness of either of the first laminated structure or the second laminated structure is made thin, fracture resistance is improved. If both of the average thicknesses of the first laminated structure and the second laminated structure are made thin, fracture resistance is further improved.


In the present invention, “continuously reduced” means, for example, that the thickness(es) of the first laminated structure and/or the second laminated structure is/are reduced from the substrate side toward the surface side with a certain regularity such as a proportional relationship. However, “continuously reduced” is not limited only to the case where the thickness(es) of the first laminated structure and/or the second laminated structure is/are reduced in accordance with the proportional relationship. For example, “continuously reduced” includes the case where the thickness(es) of the first laminated structure and/or the second laminated structure is/are reduced in accordance with the relation of inverse proportion or exponential relationship. In addition, “continuously reduced” also includes the case where the thickness tends to be reduced from the substrate side toward the surface side. This is because, even in this case, the effect of the present invention can be obtained. For example, the case where a part of the thickness of the coating layer is slightly increased from the substrate side toward the surface side is also included in the scope of the right of the present invention.


In the present invention, “stepwisely reduced” means, for example, that the thickness(es) of the first laminated structure and/or the second laminated structure is/are reduced irregularly from the substrate side toward the surface side. For example, “stepwisely reduced” includes the case where the thickness of the first laminated structure and/or the second laminated structure at the outermost surface alone is/are reduced. In addition, “stepwisely reduced” also includes the case where the thickness tends to be reduced from the substrate side toward the surface side. This is because, even in this case, the effect of the present invention can be obtained. For example, the case where a part of the thickness of the coating layer is slightly increased from the substrate side toward the surface side is also included in the scope of the right of the present invention.


When the average thickness of the first laminated structure nearest to the surface of the coating layer is made TA1, and the average thickness of the first laminated structure nearest to the substrate is made TB1, then a ratio of TA1 to TB1 ((TA1/TB1)×100) is preferably 5% or more and 50% or less, more preferably 5% or more and 30% or less. If the ratio of TA1 to TB1 is less than 5%, the effect of suppressing propagation of the cracks to the substrate may be lowered. On the other hand, if the ratio of TA1 to TB1 exceeds 50%, the effect of suppressing propagation of the cracks to the substrate may be lowered.


When the average thickness of the second laminated structure nearest to the surface of the coating layer is made TA2, and the average thickness of the second laminated structure nearest to the substrate is made TB2, then a ratio of TA2 to TB2 ((TA2/TB2)×100) is preferably 5% or more and 50% or less, more preferably 5% or more and 30% or less. If the ratio of TA2 to TB2 is less than 5%, the effect of suppressing propagation of the cracks to the substrate may be lowered. Further, wear resistance is also lowered in some cases. On the other hand, if the ratio of TA2 to TB2 exceeds 50%, the effect of suppressing propagation of the cracks to the substrate may be lowered.


The average thickness of the respective layers constituting the first laminated structure and the second laminated structure is preferably reduced continuously or stepwisely from the substrate side toward the surface side of the coating layer. This is because lowering in wear resistance can be suppressed, whereby fracture resistance is improved.


In the present invention, “continuously reduced” means, for example, that the average thickness of the respective layers constituting the first laminated structure and/or the second laminated structure are reduced from the substrate side toward the surface side with a certain regularity such as a proportional relationship. However, “continuously reduced” is not limited only to the case where the average thickness of the respective layers constituting the first laminated structure and/or the second laminated structure is reduced in accordance with the proportional relationship. For example, “continuously reduced” includes the case where the thicknesses of the respective layers are reduced in accordance with the relation of inverse proportion or exponential relationship. In addition, “continuously reduced” also includes the case where the thickness tends to be reduced from the substrate side toward the surface side. This is because, even in this case, the effect of the present invention can be obtained. For example, the case where a part of the thickness of the coating layer is slightly increased from the substrate side toward the surface side is also included in the scope of the right of the present invention.


In the present invention, “stepwisely reduced” means, for example, that the thicknesses of the respective layers constituting the first laminated structure and/or the second laminated structure are reduced irregularly from the substrate side toward the surface side. For example, “stepwisely reduced” includes the case where the thicknesses of the respective layers constituting the first laminated structure and/or the second laminated structure at the outermost surface alone are reduced. In addition, “stepwisely reduced” also includes the case where the thickness tends to be reduced from the substrate side toward the surface side. This is because, even in this case, the effect of the present invention can be obtained. For example, the case where a part of the thickness of the coating layer is slightly increased from the substrate side toward the surface side is also included in the scope of the right of the present invention.


When the average thickness of the layers contained in the first laminated structure nearest to the surface of the coating layer is made TC1, and the average thickness of the layers contained in the first laminated structure nearest to the substrate is made TD1, then a ratio of TC1 to TD1 ((TC1/TD1)×100) is preferably 12% or more and 70% or less, more preferably 30% or more and 60% or less. If the ratio of TC1 to TD1 is less than 12%, hardness of the surface side of the coating layer becomes high, whereby fracture resistance tends to be lowered. On the other hand, if the ratio of TC1 to TD1 exceeds 70%, wear resistance of the surface side of the coating layer tends to be lowered.


Incidentally, “the average thickness of the layers contained in the first laminated structure” is a value obtained as follows.


For example, when Layer A1 and Layer B1 are laminated in this order repeating 100 times as Layer A1→Layer B1→Layer A1→Layer B1→Layer A1→Layer B1→ . . . , the sum of the laminating cycles repeated 100 times is obtained. Next, a value in which the sum of the laminating cycles is divided by 100 which is a number of the times repeated is obtained. This value is “the average thickness of the layers contained in the first laminated structure”. That is, when the first laminated structure comprises “Layer A1→Layer B1→Layer A1→Layer B1→Layer A1→Layer B1→ . . . ”, the average thickness of “Layer A1→Layer B1” is “the average thickness of the layers contained in the first laminated structure”.


When the average thickness of the layers contained in the second laminated structure nearest to the surface of the coating layer is made TC2, and the average thickness of the layers contained in the second laminated structure nearest to the substrate is made TD2, then a ratio of TC2 to TD2 ((TC2/TD2)×100) is preferably 5% or more and 70% or less, more preferably 30% or more and 60% or less. If the ratio of TC2 to TD2 is less than 5%, hardness of the surface side of the coating layer becomes high, whereby fracture resistance tends to be lowered. On the other hand, if the ratio of TC2 to TD2 exceeds 70%, wear resistance of the surface side of the coating layer tends to be lowered.


Incidentally, “the average thickness of the layers contained in the second laminated structure” is a value obtained as follows.


For example, when Layer A2 and Layer B2 are laminated in this order repeating 100 times as Layer A2→Layer B2→Layer A2→Layer B2→Layer A2→Layer B2→ . . . , the sum of the laminating cycles repeated 100 times is obtained. Next, a value in which the sum of the laminating cycles is divided by 100 which is a number of the times repeated is obtained. This value is “the average thickness of the layers contained in the second laminated structure”. That is, when the second laminated structure comprises “Layer A2→Layer B2→Layer A2→Layer B2→Layer A2→Layer B2→ . . . ”, the average thickness of “Layer A2→Layer B2” is “the average thickness of the layers contained in the second laminated structure”.


A process for preparing the coating layer in the coated tool of the present invention is not particularly limited. For example, the coating layer can be prepared by the physical vapor deposition method such as the ion plating method, the arc ion plating method, the sputtering method and the ion mixing method, etc. For example, the first laminated structure and the second laminated structure explained above can be formed on the substrate by the physical vapor deposition method. In particular, the coating layer formed by the arc ion plating method has high adhesiveness to the substrate. Accordingly, among these methods, the arc ion plating method is preferred.


The respective layers can be formed onto the surface of the substrate by the conventional coating method. According to the above, the coated tool of the present invention can be prepared.


The process for preparing the coated tool of the present invention is, for example, as follows.


A substrate processed to a tool shape is charged in a reaction vessel of a physical vapor deposition device. Next, inside the reaction vessel is evacuated until a pressure becomes 1×10−2 Pa or lower. After evacuation, the substrate is heated to 200 to 800° C. by a heater in the reaction vessel. After heating, an Ar gas is introduced into the reaction vessel, and the pressure is made 0.5 to 5.0 Pa. Under the Ar gas atmosphere with the pressure of 0.5 to 5.0 Pa, a bias voltage with −200 to −1000V is applied to the substrate. A current with 5 to 20 A is passed through the tungsten filament in the reaction vessel. The surface of substrate is subjected to an ion bombardment treatment by an Ar gas. After the surface of the substrate is subjected to the ion bombardment treatment, the reaction vessel is evacuated so that a pressure inside thereof becomes 1×10−2 Pa or lower.


Then, a reaction gas such as a nitrogen gas, etc., is introduced into the reaction vessel. By making the pressure in the reaction vessel 0.5 to 5.0 Pa, a bias voltage with −10 to −150V is applied to the substrate. By evaporating the metal evaporation sources depending on the metal components of the respective layers by an arc discharge, the respective layers can be formed onto the surface of the substrate. Incidentally, two or more kinds of metal evaporation sources placed in a position apart from each other are evaporated by an arc discharge, and the table onto which a substrate has been fixed is rotated to form a layer constituting the first laminated structure or the second laminated structure. In this case, by adjusting a rotation number of the table onto which the substrate has been fixed in the reaction vessel, the thicknesses of the respective layers constituting the first laminated structure or the second laminated structure can be controlled. By alternately evaporating two or more kinds of metal evaporation sources by an arc discharge, a layer constituting the first laminated structure or the second laminated structure can be also formed. In this case, by adjusting arc discharge times of the metal evaporation sources respectively, the thicknesses of the respective layers constituting the first laminated structure or the second laminated structure can be controlled.


The thicknesses of the respective layers constituting the coating layer and the thicknesses of the respective laminated structures can be measured by observing the cross-sectional structure of the coated tool. For example, the thicknesses of the respective layers constituting the coating layer and the thicknesses of the respective laminated structures can be measured by using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), etc.


The average thicknesses of the respective layers constituting the coating layer and the average thicknesses of the respective laminated structures can be obtained as follows.


At the position nearer to 50 μm from the cutting edge of the surface opposed to the metal evaporation sources toward the center portion of said surface, the cross-sectional surface of the coated tool is observed at the three portions or more. From the observed cross-sectional surface, thicknesses of the respective layers and thicknesses of the respective laminated structure are measured. By calculating the average value of the measured thicknesses, the average thickness can be obtained.


The compositions of the respective layers of the coated tool of the present invention can be measured from the cross-sectional structure of the coated tool by using an energy dispersive X-ray spectrometry (EDS) or a wavelength dispersive X-ray spectrometry (WDS), etc.


A kind of the coated tool of the present invention may be specifically a tool for milling or turning. Examples of such a tool may be an indexable cutting insert, a drill and an end mill.


Example 1

A cemented carbide corresponding to P10 with an ISO standard SEEN1203AGTN insert shape was prepared as the substrate. In the reaction vessel of an arc ion plating device, metal evaporation sources which became the compositions of the respective layers shown in Table 1 and Table 2 were arranged. The prepared substrate was fixed to fixing metal fitting of a rotary table in the reaction vessel.


Thereafter, inside the reaction vessel was evacuated until the pressure therein became 5.0×10−3 Pa or lower. After evacuation, the substrate was heated by a heater in the reaction vessel until the temperature thereof became 500° C. After heating, an Ar gas was introduced into the reaction vessel so that the pressure in the reaction vessel became 5.0 Pa.


At an Ar gas atmosphere with a pressure of 5.0 Pa, a bias voltage with −1,000V was applied to the substrate. A current of 10 A was passed through the tungsten filament in the reaction vessel. Under such conditions, the ion bombardment treatment by an Ar gas was carried out for 30 minutes to the surface of the substrate. After completion of the ion bombardment treatment, inside the reaction vessel was evacuated until the pressure in the reaction vessel became 5.0×10−3 Pa or lower.


After evacuation, a nitrogen gas was introduced into the reaction vessel, and inside the reaction vessel was made a nitrogen gas atmosphere with a pressure of 2.7 Pa. A bias voltage of −50V was applied to the substrate. The respective layers were formed by evaporating the metal evaporation sources by an arc discharge with an arc current of 200 A.


When Layer A1 and Layer B1 of Present products 1 to 9 and Comparative products 1 and 2 were to be formed, the metal evaporation sources of Layer A1 and the metal evaporation sources of Layer B1 were alternately evaporated by an arc discharge to form Layer A1 and Layer B1. At this time, the respective arc discharge times were so adjusted that Layer A1 and Layer B1 have the thicknesses shown in Table 3. In Comparative product 3 having a thick thickness of the layer, the metal evaporation sources of Layer X and the metal evaporation sources of Layer Y were similarly evaporated by the arc discharge alternately to form Layer X and Layer Y. At this time, the thickness of Layer X and the thickness of Layer Y were controlled by adjusting the arc discharge time at the time of forming the respective layers.


When Layer A2 and Layer B2 of Present products 1 to 9 and Comparative products 1 and 2 were to be formed, the metal evaporation sources of Layer A2 and the metal evaporation sources of Layer B2 were evaporated by an arc discharge simultaneously to form Layer A2 and Layer B2. At this time, the number of rotation of the table was adjusted within the range of 0.2 to 10 min−1 so that Layer A2 and Layer B2 have the thicknesses shown in Table 3. In Comparative product 4 having a thin thickness of the layer, the metal evaporation sources of Layer X and the metal evaporation sources of Layer Y were similarly evaporated by the arc discharge simultaneously to form Layer X and Layer Y. At this time, the thickness of Layer X and the thickness of Layer Y were controlled by adjusting the number of rotation of the table within the range of 0.2 to 10 min−1.


Comparative product 5 is constituted by layers having a thin thickness and layers having a thick thickness alternately laminated. The thicknesses of the layers constituting Comparative product 5 were controlled by adjusting the arc discharge time and the number of rotation of the table. The number of rotation of the table was adjusted within the range of 0.2 to 10 min−1. The monolayer of Comparative product 6 was formed by evaporating the metal evaporation sources by an arc discharge with an arc current of 200 A while applying a bias voltage of −50V to the substrate.


The respective layers were formed onto the surface of the substrate until the layers became predetermined thicknesses shown in Table 3 and Table 4. Thereafter, a power of the heater was turned off, and after the temperature of the sample became 100° C. or lower, the sample was taken out from the reaction vessel.












TABLE 1









First laminated structure
Second laminated structure












LAYER A1
LAYER B1
LAYER A2
LAYER B2


Sample No.
Composition
Composition
Composition
Composition





Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 1


Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 2


Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 3


Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 4


Present
(Ti0.50Al0.50)N
(Ti0.33Al0.67)N
(Ti0.50Al0.50)N
(Ti0.33Al0.67)N


product 5


Present
(Ti0.50Al0.50)N
(Ti0.33Al0.67)N
(Ti0.50Al0.50)N
(Ti0.33Al0.67)N


product 6


Present
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N


product 7


Present
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N


product 8


Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 9


Comparative
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 1


Comparative
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N


product 2


















TABLE 2









Coating layer



Alternate laminate










Average thickness

















LAYER X







and






LAYER Y






Repeated
Total



Composition
LAYER X
LAYER Y
times
thickness













Sample No.
LAYER X
LAYER Y
(nm)
(nm)
(times)
(μm)
















Comparative
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
100
100
20
4.00


product 3


Comparative
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
10
10
200
4.00


product 4


Comparative
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N
10
100
40
4.40


product 5









Comparative
(Ti0.50Al0.50)N Monolayer
4.00


product 6



















TABLE 3









First laminated
Second laminated



structure
structure












LAYER A1
LAYER B1
LAYER A2
LAYER B2



Average
Average
Average
Average



thickness
thickness
thickness
thickness


Sample No.
(nm)
(nm)
(nm)
(nm)














Present
100
100
10
10


product 1


Present
60
60
2
2


product 2


Present
250
250
10
10


product 3


Present
100
100
55
55


product 4


Present
300
300
50
50


product 5


Present
200
200
2
2


product 6


Present
100
100
10
10


product 7


Present
80
80
2
2


product 8


Present
150
150
30
30


product 9


Comparative
100
100
10
10


product 1


Comparative
200
200
2
2


product 2


















TABLE 4









Coating layer











First layer





(Substrate side)
Second layer



Layer A1 and Layer B1
Layer A2 and Layer B2
Third layer












Average

Average
Layer A1 and Layer B1


















Repeated
thickness

Repeated
thickness

Repeated
Average


Sample
Laminated
times
(μm)
Laminated
times
(μm)
Laminated
times
thickness


No.
structure
(times)
TB1
structure
(times)
TB2
structure
(times)
(μm)





Present
First
6
1.20
Second
50
1.00
First
4
0.80


product 1


Present
First
8
0.96
Second
250
1.00
First
6
0.72


product 2


Present
First
4
2.00
Second
50
1.00
First
2
1.00


product 3


Present
First
6
1.20
Second
20
2.20
First
4
0.80


product 4


Present
First
8
4.80
Second
30
3.00
First
4
2.40


product 5


Present
First
15
6.00
Second
120
0.48
First
4
1.60


product 6


Present
First
6
1.20
Second
300
6.00
First
2
0.40


product 7


Present
First
8
1.28
Second
8
0.03
First
2
0.32


product 8


Present
First
10
3.00
Second
10
0.60
First
3
0.90


product 9


Comparative
First
5
1.00
Second
50
1.00
First
5
1.00


product 1


Comparative
First
3
1.20
Second
50
0.20
First
3
1.20


product 2












Coating layer














Sixth layer





Fifth layer
(Surface side)



Fourth layer
Layer A1 and Layer B1
Layer A2 and Layer B2














Layer A2 and Layer B2

Average

Average




















Repeated
Average

Repeated
thickness

Repeated
thickness
Total


Sample
Laminated
times
thickness
Laminated
times
(μm)
Laminated
times
(μm)
thickness


No.
structure
(times)
(μm)
structure
(times)
TA1
structure
(times)
TA2
(μm)





Present
Second
30
0.60
First
2
0.40
Second
10
0.20
4.20


product 1


Present
Second
150
0.60
First
4
0.48
Second
50
0.20
3.96


product 2


Present
Second
20
0.40






4.40


product 3


Present
Second
10
1.10
First
2
0.40
Second
 5
0.55
6.25


product 4


Present
Second
15
1.50






11.70


product 5


Present
Second
28
0.11
First
2
0.80
Second
10
0.04
9.03


product 6


Present
Second
70
1.40






9.00


product 7


Present
Second
4
0.02






1.65


product 8


Present
Second
10
0.60
First
2
0.60
Second
10
0.60
6.30


product 9


Comparative
Second
50
1.00
First
5
1.00
Second
50
1.00
6.00


product 1


Comparative
Second
50
0.20
First
3
1.20
Second
50
0.20
4.20


product 2





*“First” and “Second” at the column of “Laminated structure” mean the first laminated structure and the second laminated structure of the Present product with the corresponding number in Table 1 and Table 2.
















TABLE 5









First laminated structure
Second laminated structure












Average

Average




thickness

thickness



Surface side/

Surface side/




Substrate side

Substrate



(%)
Reduction in
side (%)
Reduction in



(TA1/TB1) ×
average
(TA2/TB2) ×
average


Sample No.
100
thickness
100
thickness














Present
33
Continuous
20
Continuous


product 1


Present
50
Continuous
20
Continuous


product 2


Present
50
Stepwise
40
Stepwise


product 3


Present
33
Continuous
25
Continuous


product 4


Present
50
Continuous
50
Continuous


product 5


Present
13
Stepwise
8
Stepwise


product 6


Present
33
Stepwise
23
Stepwise


product 7


Present
25
Stepwise
50
Stepwise


product 8


Present
20
Stepwise
100
Not reduced


product 9


Comparative
100
Not reduced
100
Not reduced


product 1


Comparative
100
Not reduced
100
Not reduced


product 2









The average thicknesses of the respective layers and the average thickness of the respective laminated structures of the obtained samples were obtained as follows.


Cross-sectional surfaces at the three portions were observed by TEM at the neighbor of the position of 50 μm from the cutting edge at the surface opposed to the metal evaporation sources of the coated tool toward the center portion of said surface. The thicknesses of the respective layers and the thicknesses of the respective laminated structures were measured, and an average value of the measured thicknesses was calculated.


The compositions of the respective layers of the obtained samples were obtained as follows.


The compositions were measured by using EDS at the cross-sectional surface at the position of 50 μm from the cutting edge at the surface opposed to the metal evaporation sources of the coated tool toward the center portion of said surface.


These measured results are also shown in Tables 1 to 4.


Incidentally, compositional ratios of metal elements of the respective layers in Tables 1 to 4 show an atomic ratio of the respective metal elements based on the whole metal elements in the metal compounds constituting the respective layers.


From the average thickness of the first laminated structure shown in Table 4, a ratio of the average thickness of the first laminated structure nearest to the surface of the coating layer based on the average thickness of the first laminated structure nearest to the substrate was obtained. Similarly, from the average thickness of the second laminated structure shown in Table 4, a ratio of the average thickness of the second laminated structure nearest to the substrate based on the average thickness of the second laminated structure nearest to the surface of the coating layer was obtained. These results are shown in Table 5.


By using the obtained samples, the following Cutting test 1 and Cutting test 2 were carried out, and fracture resistance and wear resistance were evaluated. The evaluation results are shown in Table 6.


[Cutting Test 1: Evaluation of Fracture Resistance]


Work piece material: SCM440,


Shape of work piece material: a rectangular parallelepiped with 105 mm×220 mm×60 mm (provided that six holes with a diameter of φ40 mm have been drilled at the surface with 105 mm×220 mm of the rectangular parallelepiped at which face milling processing is to be carried out.)


Cutting speed: 260 m/min,


Feed: 0.4 mm/tooth,


Depth of cut: 2.0 mm,


Cutting width: 105 mm,


Coolant: none,


Cutter effective diameter: φ125 mm,


Evaluation item: A processed length until the sample had been defected (defect is generated at the cutting blade portion of the sample) was measured as the tool life. A processed length until the sample had fractured was measured.


[Cutting Test 2: Evaluation of Wear Resistance]


Work piece material: SCM440,


Shape of work piece material: a rectangular parallelepiped with 105 mm×220 mm×60 mm,


Cutting speed: 260 m/min,


Feed: 0.12 mm/tooth,


Depth of cut: 2.0 mm,


Cutting width: 50 mm,


Coolant: none,


Cutter effective diameter: φ100 mm,


Evaluation item: A processed length until the maximum flank wear width had become 0.2 mm was the tool life. The processed length until the maximum flank wear width had reached 0.2 mm was measured.


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 1 is as follows.


⊚: 11 m or more


◯: 10.5 m or more and less than 11 m


Δ: 10 m or more and less than 10.5 m


X: Less than 10 m


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 2 is as follows.


⊚: 5 m or more


◯: 4.5 m or more and less than 5 m


Δ: 4 m or more and less than 4.5 m


X: Less than 4 m


An order of the evaluation is (Excellent) ⊚>◯>Δ>X (Poor). The evaluation of ⊚ or ◯ means that cutting performance is excellent. The results of the obtained total evaluation are shown in Table 6.












TABLE 6









Cutting test 1
Cutting test 2



Wear resistance test
Fracture resistance test












Tool life

Tool life



Sample No.
(m)
Evaluation
(m)
Evaluation














Present product 1
10.2
Δ
5.4



Present product 2
10.5

5.1



Present product 3
10.3
Δ
5.3



Present product 4
10.5

5.9



Present product 5
11.5

5.7



Present product 6
12.1

5.5



Present product 7
10.8

6.7



Present product 8
12.7

4.7



Present product 9
10.7

5.1



Comparative product 1
10.3
Δ
4.2
Δ


Comparative product 2
10.4
Δ
3.8
X


Comparative product 3
9.7
X
3.8
X


Comparative product 4
9.6
X
3.6
X


Comparative product 5
9.7
X
3.7
X


Comparative product 6
8.5
X
3.3
X









From the results of Table 6, the results of the wear resistance test of Present products were Δ or higher. The results of the wear resistance of Present products were equal to those of Comparative products or more in the point of not evaluated to as X. In addition, the results of the fracture resistance test of all the Present products were ⊚ or ◯. The results of the fracture resistance test of Comparative products were Δ or x. From these results, it can be understood that Present products are excellent in fracture resistance than Comparative products. From these results, it can be understood that tool lives of Present products are elongated. As can be seen from these results, according to the present invention, fracture resistance could be improved without lowering wear resistance of the coated tool.


Example 2

A cemented carbide corresponding to P10 with an ISO standard SEEN1203AGTN insert shape was prepared as the substrate. In the reaction vessel of an arc ion plating device, metal evaporation sources which became the compositions of the respective layers shown in Table 7 were arranged. According to the same preparation method as in Example 1, the samples having layer constitutions shown in Tables 8 and 9 were prepared.


Present product 10 and Comparative product 10 were prepared as follows.


In the reaction vessel of the arc ion plating device, metal evaporation sources which became the compositions of the respective layers shown in Table 7 were arranged. A mixed gas of an N2 gas and a CH4 gas was introduced into the reaction vessel. A partial pressure ratio of the N2 gas and the CH4 gas in the mixed gas is N2:CH4=1:1. A pressure in the reaction vessel is 2.7 Pa. The respective layers were prepared in the same manner as in Example 1 except for setting the atmosphere in the reaction vessel as mentioned above, and the samples having layer constitutions shown in Tables 8 and 9 were prepared.


Present product 18 was prepared as follows.


In the reaction vessel of the arc ion plating device, metal evaporation sources which became the compositions of the respective layers shown in Table 7 were arranged. When an oxide layer was to be formed, an O2 gas was introduced into the reaction vessel, and a pressure in the reaction vessel was controlled to 2.7 Pa. Thereafter, when a nitride layer was to be formed, the O2 gas was exhausted from the reaction vessel, an N2 gas was introduced into the reaction vessel, and a pressure in the reaction vessel was controlled to 2.7 Pa. The samples having layer constitutions shown in Tables 8 and 9 were prepared in the same manner as in Example 1 except for setting the atmosphere in the reaction vessel as mentioned above.












TABLE 7









First laminated structure
Second laminated structure












LAYER A1
LAYER B1
LAYER A2
LAYER B2


Sample No.
Composition
Composition
Composition
Composition





Present
(Ti0.50Al0.50)CN
(Ti0.67Al0.33)CN
(Ti0.50Al0.50)CN
(Ti0.67Al0.33)CN


product 10


Present
(Ti0.50Al0.50)N
(Al0.45Ti0.45Si0.10)N
(Ti0.50Al0.50)N
(Al0.45Ti0.45Si0.10)N


product 11


Present
(Ti0.50Al0.50)N
(Al0.45Ti0.45Sr0.10)N
(Ti0.50Al0.50)N
(Al0.45Ti0.45Sr0.10)N


product 12


Present
(Ti0.50Al0.50)N
(Al0.45Ti0.45Y0.10)N
(Ti0.50Al0.50)N
(Al0.45Ti0.45Y0.10)N


product 13


Present
(Ti0.50Al0.50)N
(Al0.50Ti0.30Cr0.20)N
(Ti0.50Al0.50)N
(Al0.50Ti0.30Cr0.20)N


product 14


Present
(Ti0.50Al0.50)N
(Al0.50Ti0.45Nb0.05)N
(Ti0.50Al0.50)N
(Al0.50Ti0.45Nb0.05)N


product 15


Present
(Ti0.67Al0.33)N
(Al0.50Ti0.45Ta0.05)N
(Ti0.67Al0.33)N
(Al0.50Ti0.45Ta0.05)N


product 16


Present
(Ti0.67Al0.33)N
(Al0.50Ti0.45W0.05)N
(Ti0.67Al0.33)N
(Al0.50Ti0.45W0.05)N


product 17


Present
(Al0.50Cr0.50)2O3
(Ti0.90Si0.10)N
(Al0.50Cr0.50)2O3
(Ti0.90Si0.10)N


product 18


Present
(Ti0.50Al0.50)N
(Al0.50Cr0.50)N
(Ti0.50Al0.50)N
(Al0.50Cr0.50)N


product 19


Present
TiN
(Ti0.40Al0.30Cr0.20Si0.10)N
TiN
(Ti0.40Al0.30Cr0.20Si0.10)N


product 20


Comparative
(Ti0.50Al0.50)N
(Al0.50Ti0.30Cr0.20)N
(Ti0.50Al0.50)N
(Al0.50Ti0.30Cr0.20)N


product 7


Comparative
TiN
(Ti0.40Al0.30Cr0.20Si0.10)N
TiN
(Ti0.40Al0.30Cr0.20Si0.10)N


product 8


Comparative
(Ti0.67Al0.33)N
(Ti0.90Si0.10)N
(Ti0.67Al0.33)N
(Ti0.90Si0.10)N


product 9


Comparative
(Ti0.50Al0.50)CN
(Ti0.67Al0.33)CN
(Ti0.50Al0.50)CN
(Ti0.67Al0.33)CN


product 10


















TABLE 8









Second laminated



structure











First laminated structure
LAYER
LAYER












LAYER A1
LAYER B1
A2
B2



Average
Average
Average
Average



thickness
thickness
thickness
thickness


Sample No.
(nm)
(nm)
(nm)
(nm)





Present product 10
100
100
10
10


Present product 11
100
100
10
10


Present product 12
100
100
10
10


Present product 13
100
100
10
10


Present product 14
100
100
10
10


Present product 15
100
100
10
10


Present product 16
100
100
10
10


Present product 17
100
100
10
10


Present product 18
100
100
10
10


Present product 19
100
100
10
10


Present product 20
100
100
10
10


Comparative
100
100
10
10


product 7


Comparative
100
100
10
10


product 8


Comparative
100
100
10
10


product 9


Comparative
100
100
10
10


















TABLE 9









Coating layer











First layer





(Substrate side)
Second layer



Layer A1 and Layer B1
Layer A2 and Layer B2
Third layer












Average

Average
Layer A1 and Layer B1


















Repeated
thickness

Repeated
thickness

Repeated
Average



Laminated
times
(μm)
Laminated
times
(μm)
Laminated
times
thickness


Sample No.
structure
(times)
TB1
structure
(times)
TB2
structure
(times)
(μm)





Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 10


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 11


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 12


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 13


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 14


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 15


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 16


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 17


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 18


Present
First
4
0.80
Second
70
1.40
First
4
0.80


product 19


Present
First
6
1.20
Second
70
1.40
First
4
0.80


product 20


Comparative
First
4
0.80
Second
40
0.80
First
4
0.80


product 7


Comparative
First
4
0.80
Second
40
0.80
First
4
0.80


product 8


Comparative
First
4
0.80
Second
40
0.80
First
4
0.80


product 9


Comparative
First
4
0.80
Second
40
0.80
First
4
0.80


product 10












Coating layer














Sixth layer





Fifth layer
(Surface side)



Fourth layer
Layer A1 and Layer B1
Layer A2 and Layer B2














Layer A2 and Layer B2

Average

Average




















Repeated
Average

Repeated
thickness

Repeated
thickness
Total



Laminated
times
thickness
Laminated
times
(μm)
Laminated
times
(μm)
thickness


Sample No.
structure
(times)
(μm)
structure
(times)
TA1
structure
(times)
TA2
(μm)





Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 10


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 11


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 12


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 13


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 14


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 15


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 16


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 17


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 18


Present
Second
40
0.80
First
4
0.80
Second
10
0.20
4.80


product 19


Present
Second
40
0.80
First
2
0.40
Second
10
0.20
4.80


product 20


Comparative
Second
40
0.80
First
4
0.80
Second
40
0.80
4.80


product 7


Comparative
Second
40
0.80
First
4
0.80
Second
40
0.80
4.80


product 8


Comparative
Second
40
0.80
First
4
0.80
Second
40
0.80
4.80


product 9


Comparative
Second
40
0.80
First
4
0.80
Second
40
0.80
4.80


product 10





*“First” and “Second” at the column of “Laminated structure” mean the first laminated structure and the second laminated structure of the Present product with the corresponding number in Table 7 and Table 8.
















TABLE 10









First laminated structure
Second laminated structure












Average

Average




thickness

thickness



Surface side/

Surface side/



Substrate side

Substrate



(%)
Reduction in
side (%)
Reduction in



(TA1/TB1) ×
average
(TA2/TB2) ×
average


Sample No.
100
thickness
100
thickness














Present
33
Continuous
14
Continuous


product 10


Present
33
Continuous
14
Continuous


product 11


Present
33
Continuous
14
Continuous


product 12


Present
33
Continuous
14
Continuous


product 13


Present
33
Continuous
14
Continuous


product 14


Present
33
Continuous
14
Continuous


product 15


Present
33
Continuous
14
Continuous


product 16


Present
33
Continuous
14
Continuous


product 17


Present
33
Continuous
14
Continuous


product 18


Present
100
Not reduced
14
Continuous


product 19


Present
33
Continuous
14
Continuous


product 20


Comparative
100
Not reduced
100
Not reduced


product 7


Comparative
100
Not reduced
100
Not reduced


product 8


Comparative
100
Not reduced
100
Not reduced


product 9


Comparative
100
Not reduced
100
Not reduced


product 10









The average thicknesses of the respective layers and the compositions of the respective layers of the obtained samples were measured in the same manner as in Example 1. These results are shown in Tables 8 to 10. In addition, Cutting test 1 and Cutting test 2 which were the same as in Example 1 were carried out by using the obtained samples to evaluate wear resistance and fracture resistance. The evaluation results are shown in Table 11.


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 1 is as follows.


⊚: 11 m or more


◯: 10.5 m or more and less than 11 m


Δ: 10 m or more and less than 10.5 m


X: Less than 10 m


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 2 is as follows.


⊚: 5 m or more


◯: 4.5 m or more and less than 5 m


Δ: 4 m or more and less than 4.5 m


X: Less than 4 m


An order of the evaluation is (Excellent) ⊚>◯>Δ>x (Poor). The evaluation of ⊚ or ◯ means that cutting performance is excellent. The results of the obtained total evaluation are shown in Table 11.












TABLE 11









Cutting test 1




Wear resistance
Cutting test 2



test
Fracture resistance test












Tool life

Tool life



Sample No.
(m)
Evaluation
(m)
Evaluation














Present product 10
10.2
Δ
5.5



Present product 11
10.4
Δ
5.3



Present product 12
10.4
Δ
5.3



Present product 13
10.1
Δ
5.6



Present product 14
10.1
Δ
5.3



Present product 15
10.3
Δ
5.4



Present product 16
10.5

5.1



Present product 17
10.5

5.2



Present product 18
10.2
Δ
5.3



Present product 19
10.1
Δ
4.9



Present product 20
10.0
Δ
5.1



Comparative product 7
9.8
X
4.1
Δ


Comparative product 8
9.7
X
4.0
X


Comparative product 9
9.8
X
4.1
Δ


Comparative product 10
9.8
X
4.1
Δ









From the results shown in Table 11, the results of the wear resistance test of Present products were Δ or more. The results of the wear resistance test of Present products were equal to those of Comparative products or more in the point of not evaluated to as X. In addition, the results of the fracture resistance test of all the Present products were ⊚ or ◯. The results of the fracture resistance test of Comparative products were Δ or X. From these results, it can be understood that Present products are excellent in fracture resistance than Comparative products. From these results, it can be understood that tool lives of Present products is elongated. As can be seen from these results, according to the present invention, fracture resistance could be improved without lowering wear resistance of the coated tool.


Example 3

Present products 21 to 27 and Comparative products 11 to 13 were prepared as follows.


A cemented carbide corresponding to P10 with an ISO standard SEEN1203AGTN insert shape was prepared as the substrate. In the reaction vessel of an arc ion plating device, metal evaporation sources which became the compositions of the respective layers shown in Table 12 and Table 13 were arranged. According to the same preparation method as in Example 1, the samples having layer constitutions shown in Tables 13, 14 and 16 were prepared.












TABLE 12









First laminated structure
Second laminated structure











Sample
LAYER A1
LAYER B1
LAYER A2
LAYER B2


No.
Composition
Composition
Composition
Composition





Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 21


Present
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N


product 22


Present
(Ti0.50Al0.50)N
(Al0.50Ti0.30Cr0.20)N
(Ti0.50Al0.50)N
(Al0.50Ti0.30Cr0.20)N


product 23


Present
(Ti0.67Al0.33)N
(Al0.50Ti0.45W0.05)N
(Ti0.67Al0.33)N
(Al0.50Ti0.45W0.05)N


product 24


Present
(Al0.50Cr0.50)N
(Ti0.90Si0.10)N
(Al0.50Cr0.50)N
(Ti0.90Si0.10)N


product 25


Present
(Ti0.50Al0.50)N
(Al0.50Ti0.45Nb0.05)N
(Ti0.50Al0.50)N
(Al0.50Ti0.45Nb0.05)N


product 26


Present
(Ti0.50Al0.50)N
(Ti0.40Al0.30Cr0.20Si0.10)N
(Ti0.50Al0.50)N
(Ti0.40Al0.30Cr0.20Si0.10)N


product 27


















TABLE 13









Coating layer



Alternately laminated layers










First layer













LAYER X





and




LAYER Y
Second layer



Average thickness
Repeated
Average thickness














Composition
LAYER X
LAYER Y
times
LAYER X
LAYER Y














Sample No.
LAYER X
LAYER Y
(nm)
(nm)
(times)
(nm)
(nm)





Comparative
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
100
100
10
90
90


product 11


Comparative
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
60
60
22
40
40


product 12


Comparative
(Ti0.67Al0.33)N
(Ti0.33Al0.67)N
60
60
25
40
40


product 13












Coating layer










Alternately laminated layers











Third layer













Second layer

LAYER X




LAYER X

and



and LAYER Y

LAYER Y



Repeated
Average thickness
Repeated
Total















times
LAYER X
LAYER Y
times
thickness



Sample No.
(times)
(nm)
(nm)
(times)
(μm)







Comparative
10
80
80
10
5.40



product 11



Comparative
22
22
20
22
5.32



product 12



Comparative
20
22
20
15
5.23



product 13
























TABLE 14









First layer




Sixth layer



(Substrate side)
Second layer


Fifth layer
(Surface side)



First laminated
Second laminated
Third layer
Fourth layer
First laminated
Second laminated



structure
structure
First laminated
Second laminated
structure
structure


















LAYER
LAYER
LAYER
LAYER
structure
structure

LAYER

LAYER




















A1
B1
A2
B2
LAYER
LAYER
LAYER
LAYER
LAYER
B1
LAYER
B2



Average
Average
Average
Average
A1
B1
A2
B2
A1
Average
A2
Average



thickness
thick-
thickness
thick-
Average
Average
Average
Average
Average
thickness
Average
thickness


Sample
(nm)
ness
(nm)
ness
thickness
thickness
thickness
thickness
thickness
(nm)
thickness
(nm)


No.
TD1
(nm)
TD2
(nm)
(nm)
(nm)
(nm)
(nm)
(nm)
TC1
(nm)
TC2






















Present
100
100
30
30
80
80
20
20
60
60
10
10


product 21


Present
150
150
30
30
60
60
10
10






product 22


Present
100
100
40
40
80
80
10
10
60
60
2
2


product 23


Present
200
200
30
30
80
80
20
20
60
60
10
10


product 24


Present
70
70
20
20
65
65
10
10
60
60
5
5


product 25


Present
70
70
30
30
70
70
20
20
70
70
10
10


product 26


Present
80
80
20
20
60
60
20
20
40
40
20
20


product 27



















TABLE 15









First laminated structure
Second laminated structure












Average

Average




thickness of

thickness of



respective

respective



layers

layers



Surface side/
Reduction in
Surface side/
Reduction in



Substrate side
average
Substrate
average



(%)
thickness of
side (%)
thickness of



(TC1/TD1) ×
respective
(TC2/TD2) ×
respective


Sample No.
100
layers
100
layers














Present
60
Continuous
33
Continuous


product 21


Present
40
Stepwise
33
Stepwise


product 22


Present
60
Continuous
5
Stepwise


product 23


Present
30
Stepwise
33
Continuous


product 24


Present
86
Continuous
25
Stepwise


product 25


Present
100
Not reduced
33
Continuous


product 26


Present
50
Continuous
100
Not reduced


product 27


















TABLE 16









Coating layer











First layer





(Substrate side)
Second layer



Layer A1 and Layer B1
Layer A2 and Layer B2
Third layer












Average

Average
Layer A1 and Layer B1


















Repeated
thickness

Repeated
thickness

Repeated
Average



Laminated
times
(μm)
Laminated
times
(μm)
Laminated
times
thickness


Sample No.
structure
(times)
TB1
structure
(times)
TB2
structure
(times)
(μm)





Present
First
6
1.20
Second
40
2.40
First
4
0.64


product 21


Present
First
6
1.80
Second
40
2.40
First
4
0.48


product 22


Present
First
4
0.80
Second
40
3.20
First
3
0.48


product 23


Present
First
8
3.20
Second
20
1.20
First
3
0.48


product 24


Present
First
10
1.40
Second
40
1.60
First
7
0.91


product 25


Present
First
6
0.84
Second
40
2.40
First
4
0.56


product 26


Present
First
6
0.96
Second
40
1.60
First
4
0.48


product 27












Coating layer














Sixth layer





Fifth layer
(Surface side)



Fourth layer
Layer A1 and Layer B1
Layer A2 and Layer B2














Layer A2 and Layer B2

Average

Average




















Repeated
Average

Repeated
thickness

Repeated
thickness
Total



Laminated
times
thickness
Laminated
times
(μm)
Laminated
times
(μm)
thickness


Sample No.
structure
(times)
(μm)
structure
(times)
TA1
structure
(times)
TA2
(μm)





Present
Second
20
0.80
First
2
0.24
Second
10
0.20
5.48


product 21


Present
Second
20
0.40






5.08


product 22


Present
Second
30
0.60
First
2
0.24
Second
20
0.08
5.40


product 23


Present
Second
15
0.60
First
2
0.24
Second
 5
0.10
5.82


product 24


Present
Second
30
0.60
First
3
0.36
Second
20
0.20
5.07


product 25


Present
Second
20
0.80
First
2
0.28
Second
10
0.20
5.08


product 26


Present
Second
35
1.40
First
2
0.16
Second
10
0.40
5.00


product 27





*“First” and “Second” at the column of “Laminated structure” mean the first laminated structure and the second laminated structure of the Present product with the corresponding number in Table 7 and Table 8.
















TABLE 17









First laminated structure
Second laminated structure












Average

Average




thickness

thickness



Surface side/

Surface side/



Substrate side

Substrate



(%)
Reduction in
side (%)
Reduction in



(TA1/TB1) ×
average
(TA2/TB2) ×
average


Sample No.
100
thickness
100
thickness














Present
20
Continuous
8
Stepwise


product 21


Present
27
Stepwise
17
Stepwise


product 22


Present
30
Continuous
3
Continuous


product 23


Present
8
Stepwise
8
Stepwise


product 24


Present
26
Stepwise
13
Continuous


product 25


Present
33
Continuous
8
Stepwise


product 26


Present
17
Continuous
25
Stepwise


product 27









The average thicknesses of the respective layers and the compositions of the respective layers of the obtained samples were measured in the same manner as in Example 1. These results are shown in Table 12 to 17. In addition, Cutting test 1 and Cutting test 2 which were the same as in Example 1 were carried out by using the obtained samples to evaluate wear resistance and fracture resistance. The evaluation results are shown in Table 18.


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 1 is as follows.


⊚: 11 m or more


◯: 10.5 m or more and less than 11 m


Δ: 10 m or more and less than 10.5 m


X: Less than 10 m


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 2 is as follows.


⊚: 5 m or more


◯: 4.5 m or more and less than 5 m


Δ: 4 m or more and less than 4.5 m


X: Less than 4 m


An order of the evaluation is (Excellent) ⊚>◯>Δ>x (Poor). The evaluation of ⊚ or ◯ means that cutting performance is excellent. The results of the obtained total evaluation are shown in Table 18.












TABLE 18









Cutting test 1
Cutting test 2



Wear resistance test
Fracture resistance test












Tool life

Tool life



Sample No.
(m)
Evaluation
(m)
Evaluation





Present
10.1
Δ
6.1



product 21


Present
10.0
Δ
6.0



product 22


Present
10.0
Δ
6.0



product 23


Present
10.3
Δ
5.4



product 24


Present
10.1
Δ
5.1



product 25


Present
10.1
Δ
5.5



product 26


Present
10.1
Δ
5.5



product 27


Comparative
10.0
Δ
4.3
Δ


product 11


Comparative
10.2
Δ
4.1
Δ


product 12


Comparative
10.2
Δ
4.3
Δ


product 13









From the results of Table 18, the results of the wear resistance test of Present products were Δ. The results of the wear resistance test of Present products were equal to those of Comparative products or more in the point of not evaluated to as X. In addition, the results of the fracture resistance test of all the Present products were ⊚. The results of the fracture resistance test of Comparative products were Δ. From these results, it can be understood that Present products are excellent in fracture resistance than Comparative products. From these results, it can be understood that tool lives of Present products are elongated. As can be seen from these results, according to the present invention, fracture resistance could be improved without lowering wear resistance of the coated tool.


Example 4

Present products 28 to 30 were prepared as follows.


A cemented carbide corresponding to P10 with an ISO standard SEEN1203AGTN insert shape was prepared as the substrate. In the reaction vessel of an arc ion plating device, metal evaporation sources which became the compositions of the respective layers shown in Table 19 were arranged. According to the same preparation method as in Example 1, the samples having layer constitutions shown in Table 20 and Table 21 were prepared.













TABLE 19









First laminated structure
Second laminated structure















Lower layer
LAYER A1
LAYER B1
LAYER A2
LAYER B2
Upper layer


Sample No.
Composition
Composition
Composition
Composition
Composition
Composition





Present
(Al0.50Ti0.30Cr0.20) N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Al0.50Ti0.30Cr0.20)N


product 28


Present
TiN
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N



product 29


Present

(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N
(Ti0.67Al0.33)N
(Ti0.50Al0.50)N


product 30



















TABLE 20









First laminated
Second laminated



structure
structure












LAYER
LAYER
LAYER
LAYER



A1
B1
A2
B2



Average
Average
Average
Average



thickness
thickness
thickness
thickness


Sample No.
(nm)
(nm)
(nm)
(nm)














Present
100
100
10
10


product 28


Present
60
60
2
2


product 29


Present
250
250
10
10


product 30


















TABLE 21









Coating layer












First






layer



(Substrate



side)
Second layer
Third layer



Lower
Layer A1 and Layer B1
Layer A2 and Layer B2
Fourth layer














layer

Average

Average
Layer A1 and Layer B1


















Average

Repeated
thickness

Repeated
thickness

Repeated
Average


Sample
thickness
Laminated
times
(μm)
Laminated
times
(μm)
Laminated
times
thickness


No.
(μm)
structure
(times)
TB1
structure
(times)
TB2
structure
(times)
(μm)





Present
0.5
First
6
1.20
Second
50
1.00
First
4
0.80


product


28


Present
0.5
First
8
0.96
Second
250
1.00
First
6
0.72


product


29


Present
0
First
4
2.00
Second
50
1.00
First
2
1.00


product


30












Coating layer
















Eighth







layer






(Surface




Sixth layer
Seventh layer
side)



Fifth layer
Layer A1 and Layer B1
Layer A2 and Layer B2
Upper















Layer A2 and Layer B2

Average

Average
layer





















Repeated
Average

Repeated
thickness

Repeated
thickness
Average
Total


Sample
Laminated
times
thickness
Laminated
times
(μm)
Laminated
times
(μm)
thickness
thickness


No.
structure
(times)
(μm)
structure
(times)
TA1
structure
(times)
TA2
(μm)
(μm)





Present
Second
30
0.60
First
2
0.40
Second
10
0.20
0.50
5.20


product


28


Present
Second
150
0.60
First
4
0.48
Second
50
0.20
0.00
4.46


product


29


Present
Second
20
0.40






0.50
4.90


product


30





*“First” and “Second” at the column of “Laminated structure” mean the first laminated structure and the second laminated structure of the Present product with the corresponding number in Table 19 and Table 20.
















TABLE 22









First laminated structure
Second laminated structure












Average

Average




thickness

thickness



Surface side/

Surface side/



Substrate side

Substrate



(%)
Reduction in
side (%)
Reduction in



(TA1/TB1) ×
average
(TA2/TB2) ×
average


Sample No.
100
thickness
100
thickness





Present
33
Continuous
20
Continuous


product 28


Present
50
Continuous
20
Continuous


product 29


Present
50
Stepwise
40
Stepwise


product 30









The average thicknesses of the respective layers and the compositions of the respective layers of the obtained samples were measured in the same manner as in Example 1. These results are shown in Tables 19 to 22. In addition, Cutting test 1 and Cutting test 2 which were the same as in Example 1 were carried out by using the obtained samples to evaluate wear resistance and fracture resistance. The evaluation results are shown in Table 23.


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 1 is as follows.


⊚: 11 m or more


◯: 10.5 m or more and less than 11 m


Δ: 10 m or more and less than 10.5 m


X: Less than 10 m


Evaluation standard of the processed length until the tool reaches its tool life in Cutting test 2 is as follows.


⊚: 5 m or more


◯: 4.5 m or more and less than 5 m


Δ: 4 m or more and less than 4.5 m


X: Less than 4 m


An order of the evaluation is (Excellent) ⊚>◯>Δ>x (Poor). The evaluation of ⊚ or ◯ means that cutting performance is excellent. The results of the obtained total evaluation are shown in Table 23.












TABLE 23









Cutting test 1
Cutting test 2



Wear resistance test
Fracture resistance test












Tool life

Tool life



Sample No.
(m)
Evaluation
(m)
Evaluation





Present
10.2
Δ
5.3



product 28


Present
10.4
Δ
5.1



product 29


Present
10.2
Δ
5.4



product 30









From the results of Table 23, the results of the wear resistance test of Present products were Δ. The results of the wear resistance test of Present products did not have X. In addition, the results of the fracture resistance test of all the Present products were ⊚. From these results, it can be understood that Present products are excellent in fracture resistance. From these results, it can be understood that Present products are elongated in tool lives whereas these have the lower layer and/or the upper layer. As can be seen from these results, according to the present invention, fracture resistance can be improved without lowering wear resistance of the coated tool.


UTILIZABILITY IN INDUSTRY

According to the present invention, fracture resistance can be improved without lowering wear resistance of the coated tool. According to the present invention, tool life can be elongated than the conventional ones. Accordingly, utilizability in industry of the present invention is high.


EXPLANATION OF REFERENCE NUMERALS




  • 1 Substrate


  • 2 Coating layer


  • 3
    a First laminated structure in which the thickness is thick at the substrate side


  • 3
    b First laminated structure in which the thickness is thin at the surface side


  • 4
    a Second laminated structure in which the thickness is thick at the substrate side


  • 4
    b Second laminated structure in which the thickness is thin at the surface side


  • 5
    a Layer A1 in which the thickness is thick at the substrate side


  • 5
    b Layer A1 in which the thickness is thin at the surface side


  • 6
    a Layer B1 in which the thickness is thick at the substrate side


  • 6
    b Layer B1 in which the thickness is thin at the surface side


  • 7
    a Layer A2 in which the thickness is thick at the substrate side


  • 7
    b Layer A2 in which the thickness is thin at the surface side


  • 8
    a Layer B2 in which the thickness is thick at the substrate side


  • 8
    b Layer B2 in which the thickness is thin at the surface side


Claims
  • 1. A coated tool which comprises: a substrate, anda coating layer formed on a surface of the substrate,wherein the coating layer contains a first laminated structure and a second laminated structure,the first laminated structure and the second laminated structure are laminated alternately and continuously twice or more,the first laminated structure contains at least two kinds of layers having different compositions, and the two kinds of layers are alternately laminated twice or more,an average thickness of the layers contained in the first laminated structure is 60 nm or more and 500 nm or less,the second laminated structure contains at least two kinds of layers having different compositions, and the two kinds of layers are alternately laminated twice or more,an average thickness of the layers contained in the second laminated structure is 2 nm or more and less than 60 nm,the layers contained in the first laminated structure and the second laminated structure contain a compound comprising: at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi, andat least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron, andan average thickness(es) of the first laminated structure and/or the second laminated structure is/are continuously or stepwisely reduced from a substrate side toward a surface side of the coating layer,wherein the average thickness of the first laminated structure is 0.2 μm or more and 6 μm or less,wherein the average thickness of the second laminated structure is 0.02 μm or more and 6 μm or less,wherein an average thickness of the coating layer is 0.22 μm or more and 12 μm or less,wherein an average thickness of the first laminated structure nearest to the surface of the coating layer is given by TA1, and an average thickness of the first laminated structure nearest to the substrate is given by TB1, a ratio of TA1 to TB1 is 5% or more and 50% or less,wherein an average thickness of the second laminated structure nearest to the surface of the coating layer is given by TA2, and an average thickness of the second laminated structure nearest to the substrate is given by TB2, a ratio of TA2 to TB2 is 5% or more and 50% or less,wherein an average thickness of the layers contained in the first laminated structure nearest to the surface of the coating layer is given by TC1, and an average thickness of the layers contained in the first laminated structure nearest to the substrate is given by TD1, a ratio of TC1 to TD1 is 12% or more and 70% or less, andwherein an average thickness of the layers contained in the second laminated structure nearest to the surface of the coating layer is given by TC2, and an average thickness of the layers contained in the second laminated structure nearest to the substrate is given by TD2, a ratio of TC2 to TD2 is 5% or more and 70% or less.
  • 2. The coated tool according to claim 1, wherein the layers contained in the first laminated structure and the layers contained in the second laminated structure contain: a compound comprising at least two metal elements selected from the group consisting of Ti, Nb, Ta, Cr, W, Al, Si, Sr and Y, andat least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron.
  • 3. The coated tool according to claim 1, wherein: the average thickness of the first laminated structure nearest to the substrate is thicker than the average thickness of the first laminated structure nearest to the surface side of the coating layer;the average thickness of the second laminated structure nearest to the substrate is thicker than the average thickness of the second laminated structure nearest to the surface side of the coating layer;the total number of layers in each of the first laminated structures decreases, with increasing distance from the substrate;the total number of layers in each of the second laminated structures decreases, with increasing distance from the substrate; andthe total number of layers in any of the first laminated structures is less than the total number of layers in any of the second laminated structures.
  • 4. A coated tool which comprises: a substrate, anda coating layer formed on a surface of the substrate,wherein the coating layer contains a first laminated structure and a second laminated structure,the first laminated structure and the second laminated structure are laminated alternately and continuously twice or more,the first laminated structure contains at least two kinds of layers having different compositions, and the two kinds of layers are alternately laminated twice or more,an average thickness of the layers contained in the first laminated structure is 60 nm or more and 500 nm or less,the second laminated structure contains at least two kinds of layers having different compositions, and the two kinds of layers are alternately laminated twice or more,an average thickness of the layers contained in the second laminated structure is 2 nm or more and less than 60 nm,the layers contained in the first laminated structure and the second laminated structure contain a compound comprising: at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Sr, Y, Sn and Bi, andat least one non-metal element selected from the group consisting of carbon, nitrogen, oxygen and boron,an average thickness of the first laminated structure nearest to the substrate is thicker than an average thickness of the first laminated structure nearest to a surface of the coating layer; andan average thickness of the second laminated structure nearest to the substrate is thicker than an average thickness of the second laminated structure nearest to the surface of the coating layer,wherein the average thickness of the first laminated structures is 0.2 μm or more and 6 μm or less,wherein the average thickness of the second laminated structures is 0.02 μm or more and 6 μm or less,wherein an average thickness of the coating layer is 0.22 μm or more and 12 μm or less,wherein the average thickness of the first laminated structure nearest to the surface of the coating layer is given by TA1, and the average thickness of the first laminated structure nearest to the substrate is given by TB1, a ratio of TA1 to TB1 is 5% or more and 50% or less,wherein the average thickness of the second laminated structure nearest to the surface of the coating layer is given by TA2, and the average thickness of the second laminated structure nearest to the substrate is given by TB2, a ratio of TA2 to TB2 is 5% or more and 50% or less,wherein an average thickness of the layers contained in the first laminated structure nearest to the surface of the coating layer is given by TC1, and an average thickness of the layers contained in the first laminated structure nearest to the substrate is given by TD1, a ratio of TC1 to TD1 is 12% or more and 70% or less, andwherein an average thickness of the layers contained in the second laminated structure nearest to the surface of the coating layer is given by TC2, and an average thickness of the layers contained in the second laminated structure nearest to the substrate is given by TD2, a ratio of TC2 to TD2 is 5% or more and 70% or less.
  • 5. The coated tool according to claim 4, wherein: at least three first laminated structures and at least three second laminated structure are laminated alternately; andthe total number of layers in each of the first laminated structures decreases, with increasing distance from the substrate; andthe total number of layers in each of the second laminated structures decreases, with increasing distance from the substrate.
  • 6. The coated tool according to claim 5, wherein: the total number of layers in any of the first laminated structures is less than the total number of layers in any of the second laminated structures.
Priority Claims (1)
Number Date Country Kind
2014-064910 Mar 2014 JP national
PCT Information
Filing Document Filing Date Country Kind
PCT/JP2015/059553 3/27/2015 WO 00
Publishing Document Publishing Date Country Kind
WO2015/147241 10/1/2015 WO A
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7923130 Shibata et al. Apr 2011 B2
20090155559 Xu et al. Jun 2009 A1
20100215951 Shibata Aug 2010 A1
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20150203956 Asari et al. Jul 2015 A1
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Entry
Extended European Search Report in corresponding application No. 15768527.2 dated Oct. 2, 2017.
International Search Report dated Jun. 23, 2015 issued in counterpart International (PCT) Application (No. PCT/JP2015/059553).
Written Opinion dated Jun. 23, 2015 issued in counterpart International (PCT) Application (No. PCT/JP2015/059553).
Japanese Patent Office, “Notification of Reasons for Refusal,” issued in connection with Japanese Patent Application No. 2016-510518, dated Apr. 3, 2018.
Related Publications (1)
Number Date Country
20180071829 A1 Mar 2018 US