JP2012035380A - Surface-coated cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool having a hard coating layer that exhibits excellent wear resistance under a high-speed cutting condition of a heat-resistant alloy such as an Ni-based alloy or a Co-based alloy.SOLUTION: The surface-coated cutting tool is composed by forming a hard coating layer on the surface of a tool base body by vapor-deposition. The hard coating layer is composed of an alternately-laminated structure of a double-layer region with a layer thickness of 100-500 nm and a single-layer region constituted of a single layer with a layer thickness of 100-500 nm. The double-layer region is formed by alternately laminating a thin layer A with a layer thickness of 1-50 nm and a thin layer B with a layer thickness of 1-50 nm. The thin layer A is a Ti nitride layer. The thin layer B is a [TiSi]N layer (X is 0.01-0.30 by atomic ratio). The single layer is composed of a layer of the same kind as the thin layer A. The surface-coated cutting tool is provided with an intermediate layer near the surface of the hard coating layer. The intermediate layer is composed of a single layer that has the same composition and components as those of the thin layer B and a layer thickness of 0.3-1 μm.

Description

  The present invention provides a surface-coated cutting tool that exhibits excellent hardness and toughness even when a heat-resistant alloy such as a Ni-base alloy or a Co-base alloy is cut under high-speed cutting conditions with high heat generation. (Hereinafter referred to as a coated tool).

  In general, for coated tools, throwaway inserts that are detachably attached to the tip of the cutting tool for turning and planing of various steel and cast iron materials, drilling of the work material, etc. Drills, miniature drills, and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting processing in the same manner as in the past is known.

  Further, as a specific coated tool, for example, a composite nitride layer of Al and Cr (hereinafter referred to as (Al, WC) is formed on the surface of a tool base made of tungsten carbide (hereinafter referred to as WC) based cemented carbide. A coated tool (hereinafter referred to as a conventional coated tool) formed by vapor-depositing a hard coating layer having a multilayer structure of a Cr (N layer) and a composite nitride layer of Ti and Si (hereinafter referred to as a (Ti, Si) N layer). It is also known that this conventional coated tool exhibits high hardness and high oxidation start temperature in high-speed cutting of alloy steel.

  In the conventional coated tool, for example, an arc ion plate in which a cathode electrode (evaporation source) made of an Al—Cr alloy and a Ti—Si alloy having a composition according to the type of hard coating layer to be deposited is disposed. In the coating apparatus, a tool base is inserted into the apparatus, the inside of the apparatus is set to a nitrogen gas reaction atmosphere, and in a heated state, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode, It is also known that the tool base is manufactured by alternately depositing (Al, Cr) N layers and (Ti, Si) N layers on the surface of the tool base under the condition that a bias voltage is applied. (For example, refer to Patent Document 1).

Special table 2008-534297

  In recent years, the performance of cutting equipment has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting work. There is also a demand for general-purpose cutting tools for various work materials. However, in the above-mentioned conventional coated tools, no particular problem arises when this is used for high-speed cutting of alloy steel. For example, Ni When used for high-speed cutting with high heat generation of heat-resistant alloys such as base alloys and Co-base alloys, the heat conductivity of heat-resistant alloys that are work materials is low, and the surface temperature of the cutting edge of the cutting tool is reduced by the cutting heat. Therefore, the wear resistance and toughness are not sufficient and chipping and chipping are likely to occur. As a result, the wear resistance of the hard coating layer is not fully demonstrated and the service life is reached in a relatively short time. It is.

  In view of the above, the present inventors, from the viewpoint as described above, generate skit wear and cause welding even when used in high-speed cutting with high heat generation of heat-resistant alloys such as Ni-base alloys and Co-base alloys. In order to develop a coated tool that exhibits excellent wear resistance with a hard coating layer without generating, chipping, or chipping, we conducted intensive research.

The Al component in the (Al, Ti) N layer constituting the hard coating layer of the conventional coated tool improves the high temperature hardness, the Ti component improves the high temperature strength, and the Ti in the (Ti, Si) N layer. The component has an effect of improving high temperature toughness and high temperature strength, and the Si component has an action of improving oxidation resistance and suppressing a decrease in hardness of the layer due to oxidation. In addition, since the hardness is improved by forming the alternate stack of the (Al, Ti) N layer and the (Ti, Si) N layer, the (Al, Ti) N layer and the (Ti, Si) N layer By providing a hard coating layer composed of an alternately laminated structure, improvement in oxidation resistance and wear resistance can be seen under normal cutting conditions.
However, in high-speed cutting of heat-resistant alloys such as Ni-base alloys and Co-base alloys, the cutting blade surface temperature becomes high, so that the internal stress ( However, when this internal stress (strain) is released by high heat during cutting, skid wear tends to progress and there is a problem that the life is short.

  Therefore, the present inventors have examined the laminated structure of the TiN layer and the (Ti, Si) N layer in more detail. As in the prior art, the hard coating layer is divided into a TiN layer and a (Ti, Si) N layer. The hard coating layer is not formed as a regular alternating layered structure, but a thin layer A composed of a TiN layer and a thin layer B composed of a (Ti, Si) N layer are alternately stacked. A hard coating layer is formed as an alternate laminated structure of a region and a single layer region composed of a single layer made of the thin layer A, and is thicker than the multilayer region and the single layer region near the surface of the hard coating layer ( When a single layer composed of a Ti, Si) N layer was obtained, the following knowledge was obtained.

That is, in the multi-layer region of the hard coating layer in which the thin layer A made of the TiN layer and the thin layer B made of the (Ti, Si) N layer are alternately laminated, the coarsening of the grains of each layer is prevented. In addition to improving film strength, it has excellent oxidation resistance and high hardness. Furthermore, the alternating layered structure of thin layer A and thin layer B prevents the propagation and progress of cracks, thereby preventing chipping. Improves chipping resistance and wear resistance.
In addition to this, the internal stress (strain) accumulated in the multilayer region as the layer thickness increases due to the formation of the single layer region composed of a single layer composed of the TiN layer in the hard coating layer. As the entire hard coating layer is relaxed by the presence of the region, large internal stress (strain) does not occur. As a result, high-speed cutting of heat-resistant alloys such as Ni-base alloys and Co-base alloys , The occurrence of delamination is suppressed.
Furthermore, high hardness and heat resistance are imparted to the hard coating layer by forming a single layer composed of a (Ti, Si) N layer thicker than the single layer region and the multilayer region near the surface of the hard coating layer, Scratch wear resistance can be improved.

The present invention has been made based on the above findings,
"In a surface-coated cutting tool in which a hard coating layer is deposited on the surface of a tool substrate,
The hard coating layer includes a multilayer region having a thickness of 100 to 500 nm and a layer having a thickness of 100 to 500 nm, in which thin layers A having a thickness of 1 to 50 nm and thin layers B having a thickness of 1 to 50 nm are alternately stacked. A lower layer having a layer thickness of 0.3 to 3.0 μm, comprising a single layer region composed of a single layer A having a thickness and configured as an alternately laminated structure of the multilayer region and the single layer region;
An intermediate layer consisting of a single layer B having a layer thickness of 0.3-1 μm;
From a single layer C having a layer thickness of 100 to 500 nm and a single layer C having a layer thickness of 100 to 500 nm in which thin layers C having a layer thickness of 1 to 50 nm and thin layers D having a layer thickness of 1 to 50 nm are alternately stacked. And an upper layer having a layer thickness of 0.2 to 1.0 μm configured as an alternate stacked structure of the multilayer region and the single layer region, and
(A) The thin layer A, the thin layer C, the single layer A, and the single layer C are:
Consisting of a nitride layer of Ti,
(B) The thin layer B, the thin layer D, and the single layer B are:
_{Formula: [Ti 1-X Si X} ] N
The surface-coated cutting tool is characterized by comprising a composite nitride layer of Ti and Si satisfying 0.01 to 0.30 (however, atomic ratio). "
It has the characteristics.
In the present invention, skid wear means wear caused by friction of the margin portion with the wall surface of the machined hole, particularly in a drill.

  The hard coating layer of the coated tool of the present invention will be described below.

Thin layer A, thin layer C (TiN layer) of the multilayer region in the lower layer and the upper layer:
A thin layer A or a thin layer C composed of a TiN layer that is alternately laminated with a thin layer B or a thin layer D ((Ti, Si) N layer) described later to form a multilayer region of the hard coating layer of the present invention, Since it is excellent in strength and interlayer adhesion, by alternately laminating with the thin layer B or the thin layer D, it complements the relatively insufficient characteristics of the thin layer B or the thin layer D, and at the same time the strength of the composite region. This is a layer for increasing the interfacial adhesion.

Thin layer B, thin layer D ((Ti, Si) N layer) in the lower layer and upper layer:
A thin layer B or a thin layer D composed of a (Ti, Si) N layer, which is alternately laminated with the thin layer A or the thin layer C (TiN layer) described above to form a multilayer region of the hard coating layer of the present invention, Since it has excellent oxidation resistance due to the Si component, it maintains excellent high hardness even at high temperatures in high-speed cutting of Ni-based alloys, Co-based alloys and the like.
A thin layer B and a thin layer D made of a (Ti, Si) N layer,
_{Formula: [Ti 1-X Si X} ] N
X is composed of a composite nitride layer of Ti and Si that satisfies 0.01 to 0.30 (however, the atomic ratio), but the value of X indicating the content ratio of Si (however, the atomic ratio) ) Is less than 0.01, the high-temperature hardness of the thin layer B and the thin layer D becomes insufficient. On the other hand, when the value of X exceeds 0.30, the thin layer B and the thin layer D Since the high temperature toughness and the high temperature strength of the steel deteriorate, the value of X is determined to be 0.01 to 0.30 (however, the atomic ratio).

Layer thickness of thin layer A, thin layer B, thin layer C, thin layer D:
In the multi-layered region formed by alternately laminating the thin layer A and the thin layer B or the thin layer C and the thin layer D, each layer is adjacent to each other to form a layer having a different composition. The coarsening of particle growth is prevented, the particle is refined, the film strength is improved, and the crack propagation and progress are prevented by this laminated structure, thereby improving the chip resistance and chipping resistance. However, if the thickness of each of the thin layer A, thin layer B, thin layer C, and thin layer D is less than 1 nm, it is difficult to clearly form each thin layer as having a predetermined composition. The above-mentioned excellent properties of the thin layer cannot be exhibited. On the other hand, if the thickness of each layer exceeds 50 nm, the film strength is reduced due to the coarsening of the particles, so that the chipping resistance and chipping resistance are reduced. Since it decreases, thin layer A, thin layer B, thin layer The respective thicknesses of the thin layer D, was defined as 1 to 50 nm.
In addition, the multi-layer region in which the thin layer A and the thin layer B or the thin layer C and the thin layer D are alternately laminated exhibits the high hardness provided by the thin layer B or the thin layer D when the region thickness is less than 100 nm. On the other hand, if the thickness of the region exceeds 500 nm, chipping and chipping are liable to occur. Therefore, thin layer A and thin layer B or thin layer C and thin layer D It is desirable that the region thickness of the multi-layered region in which and are alternately stacked is 100 to 500 nm.

Single layer A, single layer C (TiN layer) in the single layer region of the lower and upper layers:
The composition and composition of the single layer A and the single layer C in the single layer region alternately laminated with the multilayer region are the same as the thin layer A and the thin layer C in the multilayer region, and this single layer has strength and adhesion. It is the same as the thin layer A and the thin layer B that it has excellent properties.
However, in addition to the above-described effects, this single layer region has a great technical significance in that the increased internal stress (strain) accumulated in the multiple layer region can be mitigated by the presence of the single layer region. There is also an effect of relaxing the impact force applied to the hard coating layer during the cutting process in this single layer region.
Therefore, as a whole hard coating layer, large internal stress (strain) is not formed in the inside, as a result, in high-speed cutting with high heat generation of heat-resistant alloys such as Ni-base alloy, Co-base alloy, Generation of delamination is suppressed.
However, when the thickness of the single-layer region is less than 100 nm, the internal stress relaxation action and impact force relaxation action cannot be sufficiently expected. On the other hand, when the thickness exceeds 500 nm, the hard coating layer as a whole is resistant to oxidation. Therefore, the region thickness of the single layer region is determined to be 100 to 500 nm.

Intermediate single layer B ((Ti, Si) N layer):
The component / composition of the single layer B formed in the vicinity of the surface of the hard coating layer, which is the most characteristic technical matter of the present invention, is the same as the thin layer B and the thin layer D described above in the multilayer region. The single layer is high in hardness and excellent in heat resistance, similar to the thin layer B and the thin layer D.
However, this intermediate layer is formed thicker than the single layer region and the multiple layer region described above, and is specified from the surface in the hard coating layer, that is, the surface that is not exposed and is not easily affected by the tool base. By forming it at a depth of 3 mm, the effect of suppressing the progress of skid wear is exhibited.
However, when the thickness of the intermediate layer is less than 0.3 μm, the above-mentioned effect cannot be expected sufficiently. On the other hand, when the thickness exceeds 1.0 μm, the high temperature toughness and high temperature strength of the hard coating layer as a whole are lowered. The thickness of the intermediate layer was determined to be 0.3 to 1.0 μm.

Lower and upper layer thickness:
As described above, the intermediate layer exerts the effect of suppressing the progress of skid wear, but it is not preferable if it is exposed on the surface of the hard coating layer because the wear tends to proceed. It is not preferable because the peel resistance is lowered due to the difference in thermal expansion coefficient between the layer and the substrate.
Therefore, the thickness of the lower layer is set to 0.3 to 3.0 μm, and the thickness of the upper layer is set to 0.2 to 1.0 μm.

  In the surface-coated cutting tool of the present invention, the hard coating layer is configured as an alternately laminated structure of a multilayer region in which thin layers A and thin layers B are alternately laminated and a single layer region composed of a single layer. At the same time, by forming the multilayer region composed of (TiSi) N and a single layer thicker than the single layer region in the vicinity of the surface, the film strength of each thin layer is improved in the multilayer region, and excellent toughness, It has weldability and suppresses the propagation and propagation of cracks, thereby improving chipping resistance, chipping resistance, and wear resistance. The internal stress (strain) that tends to form and accumulate in the layer region is alleviated, so that delamination caused by this can be prevented, and the mechanical impact applied during cutting can also be alleviated. Moreover, it was provided near the surface. Since a single layer made of TiSi) N exerts the effect of suppressing skit wear, excellent cutting over a long period of time when used in high-speed cutting with high heat generation of heat-resistant alloys such as Ni-base alloys and Co-base alloys. Demonstrate performance.

The arc ion plating apparatus used for forming a hard coating layer is shown, (a) is a schematic plan view, and (b) is a schematic front view. It is a cross-sectional schematic diagram of the hard coating layer of the coated tool of this invention.

  Next, the coated tool of the present invention will be specifically described with reference to examples.

[Tool body forming]
As raw material powders, WC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are blended in the composition shown in Table 1. The mixture is wet mixed in a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact is sintered in a 6 Pa vacuum at a temperature of 1400 ° C. for 1 hour. After the sintering, honing of R: 0.02 was applied to the cutting edge portion to form tool bases A-1 to A-5 made of a WC-based cemented carbide having a chip shape of ISO standard / CNMG120408.

<Manufacturing process of the present coated chip>
[Installation and pretreatment of tool base on the device]
(A) Next, each of the tool bases A-1 to A-5 is ultrasonically cleaned in acetone and dried, and the center axis on the rotary table in the arc ion plating apparatus shown in FIG. Attached along the outer periphery at a predetermined distance in the radial direction from the surface, as a cathode electrode (evaporation source) on one side, TiN layer forming metal Ti, as a cathode electrode (evaporation source) on the other side, A Ti—Si alloy for forming a (Ti, Si) N layer having a component composition corresponding to the target composition shown in FIG.
The cathode electrode (evaporation source) made of metal Ti is used for vapor deposition formation of thin layer A, thin layer C, single layer A, single layer C and bombard cleaning of the tool base, and is made of Ti-Si alloy. (Evaporation source) is used for vapor deposition formation of the thin layer B, the thin layer D, and the single layer B.
[Bombard cleaning process of tool base surface]
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then the tool substrate that rotates while rotating on the rotary table is −1000 V A DC bias voltage is applied, for example, a current of 200 A is passed between the metal Ti cathode electrode and the anode electrode to generate arc discharge, and the tool base surface is bombarded.
[Formation of lower layer of hard coating layer]
(C) (Formation of a single layer region) Next, while introducing nitrogen gas as a reaction gas into the apparatus and maintaining a reaction atmosphere of 7 Pa, while rotating on the rotary table at a speed of 6 to 48 rpm, A DC bias voltage of −30 V is applied to a tool base having a multilayer region that rotates (revolves) at a speed of 1 to 8 rpm around the rotation center axis, and 150 A is applied between the metal Ti cathode electrode and the anode electrode. Is generated to form a single layer region having a target composition and a target layer thickness shown in Tables 2 and 3 on the surface of the tool base.
(D) (Formation of multi-layer region) Further, while introducing nitrogen gas as a reaction gas into the apparatus to form a reaction atmosphere of 7 Pa, while rotating on the rotary table at a speed of 6 to 48 rpm, A DC bias voltage of −30 V is applied to the tool base that rotates (revolves) around the rotation center axis of the rotary table at a speed of 1 to 8 rpm, and a current of 100 A flows between the metal Ti cathode electrode and the anode electrode. Arc discharge is generated, and at the same time, an arc discharge is generated by flowing a current of 100 A between a Ti-Si alloy cathode electrode and an anode electrode arranged opposite to the metal Ti cathode electrode with a rotary table interposed therebetween, A thin layer A is deposited on the tool base located near the Ti cathode electrode, and a thin layer B is deposited on the tool base located near the Ti-Si alloy cathode electrode. By rotating the rotary table, a thin layer B is deposited on the tool base on which the thin layer A is deposited, and a thin layer C is deposited on the tool base on which the thin layer B is deposited. Then, the thin layer A and the thin layer B are alternately deposited repeatedly, whereby the thin layer A and the thin layer B having the target composition and the target layer thickness shown in Tables 2 and 3 are alternately formed on the surface of the tool base. A stacked multilayer region is formed.
(E) The steps (c) and (d) are alternately repeated until the thickness of the lower layer of the target hard coating layer shown in Table 3 is reached.
[Formation of intermediate layer of hard coating layer]
(F) Next, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 7 Pa, and while rotating on the rotary table at a speed of 6 to 48 rpm, A DC bias voltage of −30 V is applied to a tool base that rotates (revolves) at a speed of 1 to 8 rpm, and a current of 100 A flows between the Ti—Si alloy cathode electrode and the anode electrode to generate arc discharge. A single layer B (intermediate layer) having a target composition and a target layer thickness shown in Tables 2 and 3 is formed on the surface of the tool substrate.
[Formation of upper layer of hard coating layer]
(G) Next, in the same manner as the above (c) to (e), a multilayer region in which thin layers C and thin layers D having target compositions and target layer thicknesses shown in Tables 2 and 3 are alternately laminated, and The single layer region composed of the single layer C having the target composition and the target layer thickness shown in Tables 2 and 3 is alternately repeated until the layer thickness of the upper layer of the target hard coating layer shown in Table 3 is reached. Vapor deposition is formed.
Through the above steps, as shown in FIG. 2, the lower layer and the upper layer having an alternate stacked structure of a multilayer region and a single layer region are provided, and (TiSi) N is interposed between the lower layer and the upper layer. The present coated chips 1 to 10 as the present invention coated tool having a throwaway tip shape defined in ISO · CNMG120408 in which a hard coating layer having an intermediate layer consisting of layers was formed by vapor deposition were produced.

<Manufacturing process of comparative coated chip>
[Pretreatment of tool substrate surface]
(H) For the purpose of comparison, these tool bases A-1 to A-5 were ultrasonically cleaned in acetone and dried, respectively, and charged into the arc ion plating apparatus shown in FIG. As the cathode electrode (evaporation source), metal Ti and a Ti—Si alloy having a component composition corresponding to the target composition shown in Table 4 are mounted, and the inside of the apparatus is first evacuated to a vacuum of 0.5 Pa or less. Then, the inside of the apparatus is heated to 500 ° C. with a heater, a DC bias voltage of −1000 V is applied to the tool base, and a current of 100 A is applied between the metal Ti of the cathode electrode and the anode electrode. The surface of the tool base is bombarded with metal Ti by causing an arc discharge to flow.
[Formation of hard coating layer]
(I) (Formation of multi-layer region) Next, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 7 Pa, and the bias voltage applied to the tool base is lowered to -30 V, and the metal Ti By generating an arc discharge between the cathode electrode and the anode electrode, a TiN layer having a target composition and a target layer thickness shown in Table 4 is vapor-deposited on the surface of the tool base, and then the Ti-Si By generating an arc discharge between the cathode electrode and the anode electrode of the alloy, a (Ti, Si) N layer having a target composition and a target layer thickness shown in Table 4 is deposited on the surface of the tool base, By alternately repeating the deposition and formation of the TiN layer and the (Ti, Si) N layer, a multi-layered region composed of alternately stacked target compositions and target layer thicknesses shown in Table 4 is formed.
(J) (Formation of single layer region) Next, while introducing nitrogen gas as a reaction gas into the apparatus and maintaining a reaction atmosphere of 7 Pa, while rotating on the rotary table at a speed of 6 to 48 rpm, A DC bias voltage of −30 V is applied to the tool base having a multilayer region that rotates (revolves) at a speed of 1 to 8 rpm around the rotation center axis, and 100 A is applied between the metal Ti cathode electrode and the anode electrode. Current is generated to generate arc discharge, thereby depositing a single layer region having a target composition and a target layer thickness shown in Table 4 on the surface of the tool base.
(K) Then, by repeating the above (i) and (j) alternately until the target layer thickness shown in Table 4 is reached, a comparison of the throwaway tip shapes defined in ISO · CNMG120408 having a hard coating layer Comparative coated tips 1 to 10 as coated tools were produced, respectively.

[Evaluation test]
Next, in the state where each of the various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1 to 10 and the comparative coated chips 1 to 10 are as follows.
Work Material: Ni-19% Cr-18.5% Fe-5.2% Cd-5% Ta-3% Mo-0.9% Ti-0.5% Al-0.3% by mass% Four longitudinally-grooved round bars at equal intervals in the length direction of a Ni-based alloy having a composition of Si-0.2% Mn-0.05% Cu-0.04% C,
Cutting speed: 35 m / min. ,
Incision: 2.5mm,
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes
A dry high-speed intermittent cutting test of a Ni-based alloy under the above conditions (cutting condition A) (normal cutting speed is 30 m / min.),
Work material: Equal intervals in the length direction of Co-based alloy having a composition of Co-23% Cr-6% Mo-2% Ni-1% Fe-0.6% Si-0.4% C in mass% 4 fluted round bars,
Cutting speed: 40 m / min. ,
Cutting depth: 3mm,
Feed: 0.45 mm / rev. ,
Cutting time: 5 minutes
A dry high-speed intermittent cutting test of a Co-based alloy under the conditions (cutting condition B) (normal cutting speed is 35 m / min.),
In each cutting test, the flank wear width of the cutting edge was measured. The measurement results are shown in Table 5.

[Tool body forming]
As raw material powders, WC powder having an average particle size of 0.8 μm, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, and 1.8 μm Co powder were prepared. 6 was added to the composition shown in FIG. 6 and added with wax, mixed in a ball mill for 24 hours in acetone, dried under reduced pressure, and then press-molded into various compacts of a predetermined shape at a pressure of 100 MPa. The body is heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a heating rate of 7 ° C./min in a vacuum atmosphere of 6 Pa, held at this temperature for 1 hour, and then sintered under furnace cooling conditions. Then, a round tool sintered body for forming a tool base is formed, and further, a diameter of the cutting edge portion × length is 10 mm × 22 mm and a twist angle is 45 degrees by grinding from the round bar sintered body. Made of WC-based cemented carbide with a 4-flute square shape Tool substrate (end mill) C-1~C-4 were prepared, respectively.

<Production process of the coated end mill of the present invention>
Next, the surfaces of these tool bases (end mills) C-1 to C-4 were ultrasonically cleaned in acetone and dried, and then inserted into the arc ion plating apparatus shown in FIG. A multilayer region where the thin layer A and the thin layer B are alternately laminated and the thin layer A having the target composition and the target layer thickness shown in Table 7 along the layer thickness direction under the same conditions as in Example 1. The present coated end mills 1 to 8 as the present coated tool were manufactured by vapor deposition of hard coated layers having an alternately laminated structure with single layer regions composed of the same components and compositions.

<Manufacture of comparative coated end mill>
For comparison purposes, the surfaces of the tool bases (end mills) C-1 to C-4 are ultrasonically cleaned in acetone and dried, and then loaded into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, the TiN layer and the (Ti, Si) N layer having the target composition and target layer thickness shown in Table 8 are formed on the surfaces of the tool bases (end mills) C-1 to C-4. Comparative coated end mills 1 to 8 as comparative coated tools having a hard coating layer formed by alternately laminating a multilayer region composed of alternating layers and a single layer region composed of a TiN layer were manufactured.

[Evaluation test]
Next, for the present invention coated end mills 1-8 and comparative coated end mills 1-8,
Work Material-Plane Dimensions: 100mm x 250mm, Thickness: 50mm, Mass%, Ni-19% Cr-14% Co-4.5% Mo-2.5% Ti-2% Fe-1.2 Ni-base alloy plate material having a composition of% Al-0.7% Mn-0.4% Si,
Cutting speed: 45 m / min. ,
Groove depth (cut): 0.25 mm,
Table feed: 85mm / min,
Ni-base alloy dry high-speed groove cutting test under the conditions (normal cutting speed and groove depth are 40 m / min. And 0.2 mm, respectively),
The cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge reached 0.1 mm, which is a guide for the service life. The measurement results are shown in Tables 7 and 8, respectively.

<Manufacture of the present invention coated drill>
The round bar sintered body produced in Example 2 was used, and from this round bar sintered body, the diameter of groove forming portion × length was 8 mm × 48 mm and the twist angle was 2 degrees by grinding. WC-base cemented carbide tool bases (drills) D-1 to D-4 having a single-blade shape were produced, respectively.

  Next, the cutting edges of these tool bases (drills) D-1 to D-4 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. A multilayer region in which thin layers A and thin layers B are alternately laminated with the target composition and target layer thickness shown in Table 9 along the layer thickness direction under the same conditions as in Example 1 And this invention covering drill 1-8 as this invention covering tool was manufactured by carrying out vapor deposition formation of the upper layer which consists of an alternate lamination structure with a single layer field, respectively.

<Manufacture of comparative coated drills>
For the purpose of comparison, honing is performed on the surfaces of the tool bases (drills) D-1 to D-4, ultrasonic cleaning is performed in acetone, and the arc ion plate shown in FIG. A TiN layer having a target composition and a target layer thickness shown in Table 10 and (Ti) is placed on the surface of the tool base (drill) D-1 to D-4 under the same conditions as in the first embodiment. As a comparative coating tool, a hard coating layer formed by alternately laminating a multi-layer region composed of an alternately laminated structure with Si, N layers and a single layer region composed of (Ti, Si) N layers is deposited. Comparative coated drills 1 to 8 were manufactured.

[Evaluation test]
Next, for the present invention coated drills 1-8 and comparative coated drills 1-8,
Work Material—Plane Size: 100 mm × 250 mm, Thickness: 50 mm, Mass%, Ni-19% Cr-18.5% Fe-5.2% Cd-5% Ta-3% Mo-0.9 Ni-based alloy plate having a composition of% Ti-0.5% Al-0.3% Si-0.2% Mn-0.05% Cu-0.04% C,
Cutting speed: 30 m / min. ,
Feed: 0.2 mm / rev. ,
Hole depth: 20mm,
Wet high-speed drilling test of Ni-based alloy under the following conditions (normal cutting speed and feed are 25 m / min. And 0.15 mm / rev., Respectively),
(Using water-soluble cutting oil), and the number of drilling operations was measured until the flank wear width of the cutting edge surface reached 0.3 mm. The measurement results are shown in Tables 9 and 10, respectively.
Moreover, about this invention coated drills 1-8 and comparative coated drills 1-8, after processing 60 holes of the same work material as described above, the amount of wear from the groove side of the margin portion to the second surface side is measured. Thus, the skid wear resistance was evaluated. The results are shown in Table 11.

  Thin layer A (thin layer C) and thin layer B (thin layer) of the present coated tip 1-10, the present coated end mill 1-8, and the present coated drill 1-8 as the present coated tool obtained as a result. D) and the single layer B constituting the multi-layer region and the single-layer region and the intermediate layer which are alternately laminated, and the comparison coating tips 1 to 10, the comparison coating end mills 1 to 8 and the comparison coating drills 1 to 8 Energy dispersive X-ray analysis using a transmission electron microscope for the composition of the TiN layer and the (Ti, Si) N layer constituting the multilayer region and the single layer region in which the layer A and the thin layer B are alternately laminated. When measured by the method, each showed substantially the same composition as the target composition.

  Moreover, when the average layer thickness of the said hard coating layer was cross-sectional measured using the scanning electron microscope, all showed the average value (average value of 5 places) substantially the same as target layer thickness.

From the results shown in Tables 5 and 7 to 11, the coated tool of the present invention is a multilayer in which the hard coating layer is formed by alternately laminating the thin layer A (thin layer C) and the thin layer B (thin layer D). And an intermediate layer composed of a single layer of (TiSi) N layer thicker than the multilayer region and the single layer region in the vicinity of the surface. As a result, the multi-layered area improves toughness, chipping resistance, fracture resistance, welding resistance, and wear resistance, and the presence of the single-layered area prevents delamination and reduces mechanical shock. Furthermore, the presence of the intermediate layer can reduce skit wear, so that it is excellent for a long time when used in high-speed cutting with high heat generation of heat-resistant alloys such as Ni-base alloys and Co-base alloys. Cutting performance (especially peel resistance, wear resistance) Exhibit.
On the other hand, there is an intermediate layer in which the hard coating layer is composed only of an alternate laminated structure of a composite region composed of alternating layers of TiN layers and (Ti, Si) N layers and a single layer region composed of TiN layers. In comparison coated tools, it is clear that high-speed cutting of heat-resistant alloys such as Ni-base alloys and Co-base alloys has a particularly short life due to insufficient skirt wear resistance.

  As described above, the coated tool of the present invention can be used for high-speed cutting of heat-resistant alloys such as Ni-base alloys and Co-base alloys with high heat generation as well as cutting of general steel and ordinary cast iron. Since it shows excellent cutting performance over a long period of time, it can satisfactorily cope with the FA of the cutting apparatus, labor saving and energy saving of cutting, and cost reduction.

Claims (1)

In a surface-coated cutting tool in which a hard coating layer is vapor-deposited on the surface of a tool substrate,
The hard coating layer includes a multilayer region having a thickness of 100 to 500 nm and a layer having a thickness of 100 to 500 nm, in which thin layers A having a thickness of 1 to 50 nm and thin layers B having a thickness of 1 to 50 nm are alternately stacked. A lower layer having a layer thickness of 0.3 to 3.0 μm, comprising a single layer region composed of a single layer A having a thickness and configured as an alternately laminated structure of the multilayer region and the single layer region;
An intermediate layer consisting of a single layer B having a layer thickness of 0.3-1 μm;
From a single layer C having a layer thickness of 100 to 500 nm and a single layer C having a layer thickness of 100 to 500 nm in which thin layers C having a layer thickness of 1 to 50 nm and thin layers D having a layer thickness of 1 to 50 nm are alternately stacked. And an upper layer having a layer thickness of 0.2 to 1.0 μm configured as an alternate stacked structure of the multilayer region and the single layer region, and
(A) The thin layer A, the thin layer C, the single layer A, and the single layer C are:
Consisting of a nitride layer of Ti,
(B) The thin layer B, the thin layer D, and the single layer B are:
_{Formula: [Ti 1-X Si X} ] N
The surface-coated cutting tool is characterized by comprising a composite nitride layer of Ti and Si satisfying 0.01 to 0.30 (however, atomic ratio).

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