JP2011235393A - Surface coated cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool having a hard coating layer which exhibits excellent wear resistance under high-speed cutting conditions for a heat-resistant alloy such as an Ni-based alloy or a Co-based alloy.SOLUTION: In the surface coated cutting tool, the hard coating layer formed of alternately laminated structure of a multilayer region having the layer thickness of 100-500 nm wherein a thin layer (A) of layer thickness of 1-50 nm and a thin layer (B) of layer thickness of 1-50 nm are alternately laminated, and a single layer region having the layer thickness of 100-500 nm is formed by vapor deposition on a surface of its tool base. The thin layer A is [AlCr]N (x is 0.30-0.80 in atomic ratio) layer, and the thin layer B is [TiSi]N (y is 0.01-0.30 in atomic ratio) layer. The single layer is composed of the same kind layer as the thin layer (A), and an intermediate layer formed of a single layer having the layer thickness of 0.3-1 μm with the same composition and component as the thin layer B is provided on the vicinity of the surface of the hard coating layer.

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, Cr) N layer constituting the hard coating layer of the conventional coated tool improves the high-temperature hardness, the Cr component improves the high-temperature toughness and high-temperature strength, and the (Ti, Si) N layer In the Ti component, the high temperature toughness and high temperature strength are improved, and the Si component has the effect of improving the oxidation resistance and suppressing the decrease in the hardness of the layer due to oxidation. In addition, since the hardness is improved by forming the alternate stack of the (Al, Cr) N layer and the (Ti, Si) N layer, the (Al, Cr) 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.

  Then, the present inventors examined the laminated structure of the (Al, Cr) N layer and the (Ti, Si) N layer in more detail, and as before, the hard coating layer was changed to (Al, Cr) N. Rather than forming a regular alternating layered structure of layers and (Ti, Si) N layers, the hard coating layer is composed of a thin layer A composed of (Al, Cr) N layers and (Ti, Si) N layers. A hard coating layer is formed as an alternate laminated structure of a multilayer region in which thin layers B made of layers are alternately laminated and a single layer region made of a single layer made of the thin layer A. When a single layer composed of a (Ti, Si) N layer thicker than the multilayer region and the single layer region was formed near the surface, the following knowledge was obtained.

That is, in the multilayer region of the hard coating layer in which the thin layer A composed of (Al, Cr) N layers and the thin layer B composed of (Ti, Si) N layers are alternately laminated, the grains of the respective layers Is prevented, and the film strength is improved, and it has excellent oxidation resistance and high hardness. Further, the alternate laminated structure of the thin layer A and the thin layer B prevents the propagation and progress of cracks. Thus, chipping resistance, chipping resistance and wear resistance are improved.
In addition to this, the internal stress (strain) accumulated in the multilayer region as the layer thickness increases due to the formation of a single layer region consisting of a single layer of (Al, Cr) N layer in the hard coating layer. ) Is relaxed by the presence of the single layer region, so that the hard coating layer as a whole does not generate large internal stress (strain), and as a result, such as Ni-based alloy, Co-based alloy, etc. Generation of delamination is suppressed in high-speed cutting of a heat-resistant alloy.
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 4.0 μm, which includes a single layer region composed of a single layer A having a thickness and is 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:
Composition formula: [Al _1-x Cr _x ] N
X is composed of a composite nitride layer of Al and Cr that satisfies 0.30 to 0.80 (however, the atomic ratio),
(B) The thin layer B, the thin layer D, and the single layer B are:
Composition formula: [Ti _1-y Si _y ] N
A surface-coated cutting tool characterized in that y is composed of a composite nitride layer of Ti and Si that satisfies 0.01 to 0.30 (however, the 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 ((Al, Cr) N layer) in the lower layer and upper layer:
A thin layer A or (Al, Cr) N layer which 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 the thin layer C is excellent in strength and interlayer adhesion, it is alternately laminated with the thin layer B or the thin layer D, thereby complementing the relatively insufficient characteristics of the thin layer B or the thin layer D at the same time. This is a layer for increasing the strength of the composite region and improving the interlayer adhesion.
A thin layer A and a thin layer C composed of (Al, Cr) N layers,
Composition formula: [Al _1-x Cr _x ] N
X is a composite nitride layer of Al and Cr that satisfies 0.30 to 0.80 (provided that the atomic ratio), and the value of X (provided that the atomic ratio) indicates the Cr content ratio. When the value is less than 0.30, the high-temperature hardness of the thin layer A or C is insufficient. On the other hand, when the value of x exceeds 0.80, the high-temperature toughness of the thin layer A or C is high. Since the strength decreases, the value of x is set to 0.30 to 0.80 (however, the atomic ratio).

Thin layer B, thin layer D ((Ti, Si) N layer) in the lower layer and upper layer:
The thin layer B or (Ti, Si) N layer which is laminated with the thin layer B or the thin layer D ((Ti, Si) N layer) described above to form the multilayer region of the hard coating layer of the present invention. Since the thin layer D has excellent oxidation resistance due to the Si component, the thin layer D maintains excellent high hardness even at high temperatures in high-speed cutting such as Ni-based alloys and Co-based alloys.
A thin layer B and a thin layer D made of a (Ti, Si) N layer,
Composition formula: [Ti _1-y Si _y ] N
Y 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 y indicating the Si content ratio (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 y exceeds 0.30, the thin layer B and the thin layer D Since the high-temperature toughness and high-temperature strength of the steel sheet are lowered, the value of y 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 ((Al, Cr) N 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 was determined to be 0.3 to 3.0 μm, and the thickness of the upper layer was determined to be 0.1 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 each other, and having a component composition corresponding to the target composition shown in Table 2 as the cathode electrode (evaporation source) on one side (Al, Cr) (Ti, Si) N-layer forming Ti- having an ingredient composition corresponding to the target composition shown in Table 2 as the N-layer forming Al-Cr alloy and the cathode electrode (evaporation source) on the other side facing each other A Si alloy is arranged with the rotary table in between.
The cathode electrode (evaporation source) made of an Al—Cr alloy is used for vapor deposition of the thin layer A, thin layer C, single layer A, single layer C and bombard cleaning of the tool base, and is made of a Ti—Si alloy. The cathode electrode (evaporation source) is used for vapor deposition 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 100 A is passed between an Al—Cr alloy cathode electrode and an anode electrode to generate an arc discharge, and the tool base surface is bombarded.
[Formation of lower layer of hard coating layer]
(C) (Formation of single layer region) Next, while introducing nitrogen gas as a reaction gas into the apparatus and maintaining the reaction atmosphere of 10 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 on which a multi-layer region rotating (revolves) at a speed of 1 to 8 rpm around the rotation center axis is applied between the Al—Cr alloy cathode electrode and the anode electrode. Then, a current of 100 A is passed through to generate an arc discharge, whereby a single layer region having a target composition and a target layer thickness shown in Tables 2 and 3 is deposited 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 make a reaction atmosphere of 10 Pa, while rotating on the rotary table at a speed of 6 to 48 rpm, A DC bias voltage of −70 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 is applied between the Al—Cr alloy cathode electrode and the anode electrode. To generate arc discharge, and at the same time, a current of 100 A is passed between the Ti—Si alloy cathode electrode and the anode electrode, which are arranged opposite to the Al—Cr alloy cathode electrode with the rotary table interposed therebetween, thereby causing the arc discharge. The thin layer A is applied to the tool base located near the Al—Cr alloy cathode electrode, and the thin layer A is applied to the tool base located near the Ti—Si alloy cathode electrode. B is vapor-deposited, and then the rotating table is rotated to deposit a thin layer B on the tool base on which the thin layer A is vapor-deposited, and a thin layer on the tool base on which the thin layer B is vapor-deposited. C is vapor-deposited, and in the same manner, thin layer A and thin layer B are alternately and repeatedly vapor-deposited on the surface of the tool base to form thin layer A having the target composition and target layer thickness shown in Tables 2 and 3. A multilayer region in which the thin layers B are alternately laminated 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 make a reaction atmosphere of 10 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), an Al—Cr alloy and a Ti—Si alloy each 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 0.5 Pa or less. The apparatus was heated to 500 ° C. with a heater while maintaining a vacuum of −1000 V, a −1000 V DC bias voltage was applied to the tool base, and the cathode electrode was placed between the Al—Cr alloy and the anode electrode. The surface of the tool base is bombarded with an Al—Cr alloy by generating an arc discharge by supplying a current of 100 A.
[Formation of hard coating layer]
(I) (Formation of Multilayer Area) Next, nitrogen gas is introduced as a reaction gas into the apparatus to make a reaction atmosphere of 10 Pa, and the bias voltage applied to the tool base is lowered to −70 V, and the Al— By generating an arc discharge between the cathode electrode and the anode electrode of the Cr alloy, an (Al, Cr) N layer having a target composition and a target layer thickness shown in Table 4 is deposited on the surface of the tool base. Then, by generating an arc discharge between the cathode electrode and the anode electrode of the Ti—Si alloy, the target composition and target layer thickness (Ti, Si) shown in Table 4 are formed on the surface of the tool base. By forming the N layer by vapor deposition and alternately repeating the vapor deposition of the (Al, Cr) N layer and the (Ti, Si) N layer, it is composed of the alternate lamination of the target composition and the target layer thickness shown in Table 4. Forming a layer region.
(J) (Formation of single layer region) Next, while introducing nitrogen gas as a reaction gas into the apparatus and maintaining a reaction atmosphere of 10 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 on which a multi-layer region rotating (revolves) at a speed of 1 to 8 rpm around the rotation center axis is applied between the Al—Cr alloy cathode electrode and the anode electrode. Then, a current of 100 A is passed through to generate an 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. ,
Cutting depth: 4 mm,
Feed: 0.35 mm / rev. ,
Cutting time: 5 minutes,
A dry high-speed intermittent cutting test of a Ni-based alloy under the conditions (cutting condition A) (normal cutting speed is 20 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: 45 m / min. ,
Cutting depth: 3 mm,
Feed: 0.5 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 (Al, Cr) N layer having the target composition and target layer thickness shown in Table 8 and (Ti) are formed on the surfaces of the tool bases (end mills) C-1 to C-4. , Si) N comparison layer end mill as a comparative coating tool having a hard coating layer formed by alternately laminating a multilayer region composed of alternating layers with N layers and a single layer region composed of (Al, Cr) N layers 1 to 8 were produced.

[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: 55 m / min. ,
Groove depth (cut): 0.7 mm,
Table feed: 60 mm / min,
Ni-base alloy dry high-speed grooving test under the conditions (normal cutting speed and groove depth are 35 m / min. And 0.5 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>
Using the round bar sintered body produced in Example 2 above, from this round bar sintered body, the diameter x length of the groove forming part was 8 mm x 48 mm and the helix angle was 30 degrees by grinding. WC base cemented carbide tool bases (drills) D-1 to D-4 each having a two-blade shape were manufactured.

  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, the surfaces of the above-mentioned tool bases (drills) D-1 to D-4 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ions shown in FIG. In the plating apparatus, under the same conditions as in Example 1, the target compositions and target layer thicknesses (Al, Cr) shown in Table 10 were formed on the surfaces of the tool bases (drills) D-1 to D-4. ) Evaporating and forming a hard coating layer formed by alternately laminating a multi-layer region composed of an alternately laminated structure of N layers and (Ti, Si) N layers and a single layer region composed of (Ti, Si) N layers. Thus, comparative coated drills 1 to 8 as comparative coated tools were produced, respectively.

[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: 40 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 15 mm,
Wet high-speed drilling test of Ni-based alloy under the following conditions (normal cutting speed and feed are 25 m / min. And 0.12 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 The composition of the (Al, Cr) N 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 is measured using a transmission electron microscope. When measured by energy dispersive X-ray analysis, 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, the hard coating layer has an alternate lamination structure of a composite region composed of alternating layers of (Al, Cr) N layers and (Ti, Si) N layers and a single layer region composed of (Al, Cr) N layers. In the comparative coated tool composed only of the intermediate layer, the high-speed cutting process of the heat-resistant alloy such as Ni-base alloy and Co-base alloy is not sufficient in skit wear resistance. It is clear that the service life is reached.

  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 4.0 μm, which includes a single layer region composed of a single layer A having a thickness and is 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:
Composition formula: [Al _1-x Cr _x ] N
X is composed of a composite nitride layer of Al and Cr that satisfies 0.30 to 0.80 (however, the atomic ratio),
(B) The thin layer B, the thin layer D, and the single layer B are:
Composition formula: [Ti _1-y Si _y ] N
A surface-coated cutting tool characterized in that y is composed of a composite nitride layer of Ti and Si that satisfies 0.01 to 0.30 (however, the atomic ratio).

Images