JP2010137336A - Surface-coated cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool having a hard coating layer, exhibiting superior chipping resistance and wear resistance over a long period of service even when a heat resisting alloy such as an Ni based alloy and a Co based alloy is machined at high speeds which generates high heat. <P>SOLUTION: In this surface-coated cutting tool, a substrate layer and an upper layer formed by alternately laminating a thin layer A and a thin layer B are formed, as a hard coating layer, on the surface of a tool base. The substrate layer and the thin layer A is composite nitride layers of Al, Cr, Si represented by the composition formula [Al<SB>X</SB>Cr<SB>Y</SB>Si<SB>Z</SB>]N. The thin layer B is a composite nitride layer of Al, Ti, Si represented by the composition formula [Al<SB>U</SB>Ti<SB>V</SB>Si<SB>W</SB>]N. The substrate layer A has a layer thickness of exceeding 0.05 μm and not over 2 μm. The thin layer A and the thin layer B each have one-layer average layer thickness of 0.005-0.05 μm. The total layer thickness of the thin layer A and the thin layer B is 1-5 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  This invention exhibits excellent chipping resistance and wear resistance even when cutting heat-resistant alloys such as Ni-base alloys and Co-base alloys under high-speed cutting conditions with high heat generation. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool).

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

In addition, as a specific coated tool, for example, on the surface of a tool base made of tungsten carbide (hereinafter referred to as WC) based cemented carbide,
Composition _{formula: [Al X Cr Y Si Z} ] N
The composite nitride layer of Al, Cr, and Si satisfying X = 0.45, Y = 0.50, Z = 0.05 (where X, Y, and Z are atomic ratios) ( Hereinafter, (shown as an Al, Cr, Si) N layer) is an A layer,
When represented by the composition formula [Al _U Ti _V ] N,
B and B are composite nitride layers of Al and Ti that satisfy U = 0.5 and V = 0.5 (wherein U and V are both atomic ratios) (hereinafter referred to as (Al, Ti) N layers). age,
By forming the hard coating layer by alternately laminating the A layer and the B layer, it has excellent oxidation resistance, high hardness, and excellent wear resistance in high-speed cutting of high-hardness steel. It is known that a coated tool (hereinafter referred to as a conventional coated tool) can be obtained.

The above-mentioned conventional coated tool is, for example, loaded with the above-mentioned tool base into an arc ion plating apparatus which is one type of physical vapor deposition apparatus shown in the schematic explanatory diagram of FIG. In the state heated to the temperature of, for example, an arc discharge is generated between the cathode electrode (evaporation source) having a component composition corresponding to the type of the hard coating layer to be vapor-deposited and the anode electrode under the condition of current: 90 A, for example. At the same time, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa. On the other hand, the hard coating layer is formed on the surface of the tool base under the condition that a bias voltage of, for example, −100 V is applied to the tool base. It is also known that it is manufactured by vapor deposition.
JP 2004-106183 A

  In recent years, the performance of cutting machines has been remarkable. On the other hand, there are strong demands for labor saving and energy saving and further cost reduction for cutting. With this, cutting tends to be faster. In the conventional coated tool, for example, when it is used for high-speed cutting with high heat generation of a heat-resistant alloy such as a Ni-base alloy and a Co-base alloy, the (Al, Cr, Si) N layer is excellent. Although it has hardness, the strength is not sufficient, and the (Al, Ti) N layer has excellent interlayer adhesion strength, but the high temperature hardness is not sufficient, so chipping, generation of defects or reduction in wear resistance, etc. At present, the service life is reached in a relatively short time.

  In view of the above, the inventors of the present invention have a particularly excellent hard coating layer even when the heat-resistant alloy such as a Ni-base alloy or a Co-base alloy is used for high-speed cutting with high heat generation. As a result of earnest research to develop a coated tool that has excellent high-temperature strength and high-temperature hardness and exhibits excellent chipping resistance and wear resistance over a long period of use, the following findings were obtained. .

(A) The Al component in the (Al, Cr, Si) N layer constituting the hard coating layer of the conventional coated tool described above improves the high temperature hardness, and the Cr component improves the high temperature toughness and high temperature strength. In addition, Al and Cr coexistingly improve the high-temperature oxidation resistance, and the Si component has the effect of improving the high-temperature hardness by refining crystal grains and at the same time improving the heat-resistant plastic deformation, In high-speed cutting of heat-resistant alloys with high heat generation, it cannot be said that high-temperature toughness and high-temperature strength are sufficient, so this is likely to cause chipping, fracture, etc. Even if an attempt is made to improve the high temperature strength, the wear resistance deteriorates due to the relative decrease in the Al content ratio, so the chip resistance in the hard coating layer made of the (Al, Cr, Si) N layer is reduced. Grayed property, that there is a limit to the improvement of the chipping resistance.

(B) On the other hand, the Al component in the (Al, Ti) N layer constituting the B layer of the hard coating layer of the conventional coated tool has the same action as described above, and the Ti component has high temperature toughness, Since it has the effect of further improving the high-temperature strength, when the alternating layering of the A layer and the B layer is configured, the B layer supplements the high temperature toughness and high temperature strength that the A layer lacks, and the fineness of the particles As a result, the strength of the film is further improved, and as a result, the chipping resistance and the chipping resistance as an entire alternate laminate are improved. However, since this B layer has insufficient high-temperature oxidation resistance, for example, In high-speed cutting of a heat-resistant alloy with high heat generation, oxidation wear is likely to occur in the B layer. Further, when the thin layers of the A layer and the B layer are alternately formed, the high heat during the cutting is high. As a result, the A layer itself is easily oxidized. Fruit, hard coating layer comprising alternate lamination of a thin layer of the A layer and the B layer, since the reduction in hardness occurs, the wear resistance tends to deteriorate.

(C) Therefore, when a small amount of Si component is added and contained in the B layer as a constituent component, and this is composed of an (Al, Ti, Si) N layer, the Al component and Ti component are the same as described above. In addition to the action, the Si component improves the high-temperature oxidation resistance of the thin layer B, so that the decrease in the hardness of the layer due to oxidation is suppressed. The thin layer B includes the (Al, Cr, Si) N layer. In the alternate lamination with the thin layer A (hereinafter referred to as “thin layer A”), there is also an effect of improving interlayer adhesion, and therefore the strength of the entire layer is improved.

(D) Accordingly, an underlayer having the same composition as the thin layer A having a relatively large layer thickness is formed on the surface of the tool base, and the thin layer A and the thin layer B are alternately formed on the surface of the underlayer. When the upper layer having a laminated structure is formed, the upper layer portion of the hard coating layer that is strongly subjected to impact during cutting is high in adhesion and high-temperature strength, and the thin layer B has improved high-temperature oxidation resistance by the Si component. Since the upper layer is composed of an alternating laminated structure with the thin layer A, the upper layer has both excellent high temperature oxidation resistance and interlayer adhesion that the thin layer B has without impairing the characteristics of the thin layer A. At the same time, the strength of the upper layer is improved by the refinement of crystal grains due to the alternate laminated structure, while the underlayer of the hard coating layer has excellent oxidation resistance and high hardness, and sufficient wear resistance is ensured. Therefore, as the hard coating layer, The coated tool having the upper layer composed of the alternating layer structure of the layer and the thin layer A and the thin layer B is used for high-speed cutting of a heat-resistant alloy such as a Ni-based alloy and a Co-based alloy with high heat generation. Even if it exists, it exhibits excellent wear resistance over long-term use without causing chipping or chipping.

This invention has been made based on the above findings,
“A surface-coated cutting tool in which a hard coating layer composed of an underlayer and an upper layer is formed on the surface of a tool substrate by vapor deposition,
(A) The underlayer has a layer thickness of more than 0.05 μm and 2 μm or less, and
Composition _{formula: [Al X Cr Y Si Z} ] N
X, Y, Z (all atomic ratios) indicating the content ratios of Al, Cr, Si are 0.45 ≦ X ≦ 0.70, 0.25 ≦ Y ≦ 0.50, 0 .02 ≦ Z ≦ 0.15, a composite nitride layer of Al, Cr and Si satisfying X + Y + Z = 1,
(B) Each of the upper layers has an alternately laminated structure of a thin layer A and a thin layer B each having an average layer thickness of 0.005 to 0.05 μm, and the total of the thin layer A and the thin layer B. The layer thickness is 1-5 μm,
(C) The thin layer A is
Composition _{formula: [Al X Cr Y Si Z} ] N
X, Y, Z (all atomic ratios) indicating the content ratios of Al, Cr, Si are 0.45 ≦ X ≦ 0.70, 0.25 ≦ Y ≦ 0.50, 0 .02 ≦ Z ≦ 0.15, a composite nitride layer of Al, Cr and Si satisfying X + Y + Z = 1,
(D) The thin layer B is
Composition _{formula: [Al U Ti V Si W} ] N
, U, V, and W (all atomic ratios) indicating the content ratios of Al, Ti, and Si are 0.40 ≦ U ≦ 0.65, 0.30 ≦ V ≦ 0.55, 0 .02 ≦ W ≦ 0.15 and a composite nitride layer of Al, Ti and Si satisfying U + V + W = 1.
A surface-coated cutting tool characterized by that. "
It has the characteristics.

Next, the hard coating layer of the coated tool of the present invention will be described in more detail.
(A) Thin layer A
The Al component in the thin layer A composed of the (Al, Cr, Si) N layer is improved in high-temperature hardness, and the Cr component is improved in high-temperature toughness and high-temperature strength. In addition, the Si component has the effect of improving high temperature hardness and heat plastic deformation. And if X value (atomic ratio) which shows the content rate of Al is less than 0.45 in the ratio which occupies for the total amount of Cr and Si, the minimum high temperature hardness and high temperature oxidation resistance cannot be ensured, If this X value exceeds 0.70, the high temperature toughness and high temperature strength will decrease, leading to chipping and chipping. 70. Further, if the Y value (atomic ratio) indicating the Cr content is less than 0.25 in the total amount of Al and Si, the minimum required high temperature toughness and high temperature strength cannot be ensured. The occurrence of chipping and defects cannot be suppressed. On the other hand, if the Y value exceeds 0.50, the progress of wear is promoted due to the decrease in the relative Al content. It was set to 0.50. Furthermore, when the Z value (atomic ratio) indicating the Si content ratio is less than 0.02 in the total amount of Al and Cr, it is expected to improve the wear resistance by improving the high temperature hardness and the heat-resistant plastic deformability. On the other hand, if the Z value exceeds 0.15, the wear resistance improving effect tends to decrease, so the Z value was determined to be 0.02 to 0.15.
For X, Y, and Z, particularly desirable ranges are 0.55 ≦ X ≦ 0.65, 0.25 ≦ Y ≦ 0.35, and 0.03 ≦ Z ≦ 0.10.

(B) Thin layer B
The thin layer B composed of the (Al, Ti, Si) N layers constituting the alternating layer structure with the thin layer A complements the characteristics (particularly chipping resistance and chipping resistance) that are lacking in the thin layer A. This is a layer provided for the purpose.
As already described, the thin layer A has excellent wear resistance especially by containing the Al component and Si component, and further has a predetermined chipping resistance and fracture resistance by containing the Cr component. In order to withstand the use of heat-resistant alloys such as Ni-base alloys and Co-base alloys with high heat generation under high-speed cutting conditions, the thin layer A is further improved in high-temperature oxidation resistance and high temperature. Toughness and high-temperature strength are required, and in order to ensure this, it is necessary to contain more Cr in the thin layer A, but in that case, the content ratio of Al and Si in the thin layer A must be reduced. In that case, since the thin layer A has insufficient high-temperature hardness and heat-resistant plastic deformability, which leads to a decrease in wear resistance, it is possible to further increase the Cr content in the thin layer A. Impossible.
Therefore, in the present invention, the thin layer B composed of the (Al, Ti, Si) N layer is alternately laminated with the thin layer A to form a hard coating layer composed of the alternately laminated structure of the thin layer A and the thin layer B. The high-temperature toughness that the thin layer A has, the high-temperature toughness that the thin layer A lacks, the high-temperature toughness that the adjacent thin layer B has, The strength of the upper layer is further improved by supplementing with high-temperature strength, and the finer particles by the alternate layered structure. As a result, the hard coating layer as a whole has excellent oxidation resistance, chipping resistance, chipping resistance, and wear resistance. It demonstrates its sexuality.
The effect of the Al component in the composition formula of the thin layer B is the same as that of the thin layer A, and the Ti component has the effect of further improving the high temperature toughness and the high temperature strength, but shows the Al content ratio. If the U value (atomic ratio) is less than 0.40, or the V value (atomic ratio) indicating the proportion of Ti exceeds 0.55, the minimum required high temperature hardness can be secured. This causes a decrease in wear resistance, and if the U value exceeds 0.65, or if the V value is less than 0.30, the effect of improving the high temperature toughness and high temperature strength by adding the Ti component can be expected. Therefore, it becomes difficult to suppress the occurrence of chipping and defects. Therefore, the U value indicating the Al content ratio was set to 0.40 to 0.65, and the V value indicating the Ti content ratio was determined to be 0.30 to 0.55.
In addition, when the W value (atomic ratio) indicating the Si content is less than 0.02, improvement in high-temperature oxidation resistance cannot be expected. On the other hand, when the W value exceeds 0.15, Since the high-temperature hardness decreases, the W value indicating the content ratio of the Si component is determined to be 0.02 to 0.15.
For U, V, and W, particularly desirable ranges are 0.45 ≦ U ≦ 0.60, 0.4 ≦ V ≦ 0.5, and 0.03 ≦ W ≦ 0.07.

(C) Layer thickness If the average layer thickness of each of the thin layer A and the thin layer B is less than 0.005 μm, it is difficult to clearly form each thin layer as having a predetermined composition, as well as fine particles. On the other hand, when the thickness of each of the thin layer A and the thin layer B exceeds 0.05 μm, the film strength tends to decrease, and at the same time, There is a risk that the layer has defects, that is, if it is a thin layer A, insufficient toughness and insufficient strength, and if it is a thin layer B, insufficient hardness appears locally in the layer, leading to deterioration of the properties of the entire hard coating layer. Therefore, the average layer thickness of each of the thin layer A and the thin layer B was determined to be 0.005 to 0.05 μm.
That is, the thin layer B is provided in order to compensate for insufficient characteristics among the characteristics of the thin layer A, but the thickness of each of the thin layers A and B is 0.005 to 0.05 μm. Within the above range, the hard coating layer composed of the alternately laminated structure of the thin layer A and the thin layer B has excellent high-temperature acid resistance without impairing excellent high-temperature hardness, high-temperature toughness, high-temperature strength, and heat-resistant plastic deformation. It acts as if it had a single layer, but if the layer thickness of the thin layer A and the thin layer B exceeds 0.2 μm, the toughness of the thin layer A, the strength is insufficient, Insufficient hardness of the thin layer B becomes apparent.
In addition, the layer (upper layer) having an alternately laminated structure of the thin layer A and the thin layer B cannot exhibit excellent characteristics when the total layer thickness is less than 1 μm, and the total layer thickness exceeds 5 μm. Then, since chipping and defects are likely to occur, the total layer thickness of the layer (upper layer) composed of the alternately laminated structure of the thin layer A and the thin layer B is determined to be 1 to 5 μm.

(D) Underlayer When alternating layers of thin layer A and thin layer B are formed directly on the surface of the tool substrate, the alternating layer impairs excellent high-temperature hardness, high-temperature toughness, high-temperature strength, and heat-resistant plastic deformation. It works as if it is a single layer with excellent high-temperature oxidation resistance, and does not cause chipping or chipping due to strong impact during cutting, but it is excellent over long-term use. In order to maintain high wear resistance, it is necessary to provide a hard coating layer with higher hardness. For this reason, the (Al, Cr, Si) N layer, that is, the A layer having a hardness superior to that of the alternate lamination, is relatively thick on the surface of the tool base as compared with each layer of the alternate lamination. By forming it as a base layer, the base layer can ensure excellent wear resistance over a long period of use.
However, if the thickness of the underlayer is 0.05 μm or less, the effect of providing the underlayer cannot be expected. On the other hand, if the thickness exceeds 2 μm, chipping and defects are likely to occur. The layer thickness was determined to be more than 0.05 μm and 2 μm or less.

  In the surface-coated cutting tool of the present invention, the hard coating layer is composed of an underlayer and an upper layer, and the upper layer includes a thin layer A composed of an (Al, Cr, Si) N layer, and (Al, Ti, By being configured as an alternating layered structure of thin layers B composed of Si) N layers, it has excellent high temperature hardness, high temperature toughness, high temperature strength, heat plastic deformation and high temperature oxidation resistance. Since the wear resistance is ensured by being formed with the same composition and thickness as the thin layer A, high-speed cutting of heat-resistant alloys such as Ni-base alloys and Co-base alloys with particularly high heat generation In processing, in addition to high-temperature hardness, high-temperature toughness, high-temperature strength, and heat-resistant plastic deformability, the hard coating layer exhibits excellent high-temperature oxidation resistance and excellent interlayer adhesion. As a result, chipping, chipping, No uneven wear or delamination Is intended to exert a long term wear resistance was.

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

As raw material powders, WC powder, ZrC 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 as shown in Table 1. Compounded into the composition, wet-mixed with a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact was maintained in a vacuum of 6 Pa at a temperature of 1400 ° C. for 1 hour. After sintering, tool bases A-1 to A-5 made of WC-based cemented carbide having an ISO standard / CNMG120408 chip shape by performing honing of R: 0.02 on the cutting edge portion. Formed.

(A) Next, each of the tool bases A-1 to A-10 is ultrasonically cleaned in acetone and dried, and the center on the rotary table in the arc ion plating apparatus shown in FIG. Attached along the outer peripheral portion at a predetermined distance in the radial direction from the shaft, as a cathode electrode (evaporation source) on one side, an underlayer and a thin layer each having a component composition corresponding to the target composition shown in Table 2 An Al—Cr—Si alloy for forming layer A, and an Al—Ti—Si alloy for forming thin layer B each having a component composition corresponding to the target composition shown in Table 2 as the cathode electrode (evaporation source) on the other side Are arranged opposite to each other with the rotary table interposed therebetween.
In FIG. 1, the cathode electrode for forming the thin layer A and the cathode electrode for forming the underlayer are used together. However, the cathode electrode for forming the thin layer A and the cathode electrode for forming the underlayer are provided separately from each other. Of course it is possible.
(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 direct current bias voltage is applied, for example, an arc discharge is generated by passing a current of 100 A between the Al—Cr—Si alloy cathode electrode and the anode electrode for forming the base layer and the thin layer A, and thereby the surface of the tool base is formed. Clean with bombard.
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and An arc discharge is generated by passing a current of 100 A between the base layer and the Al-Cr-Si alloy for forming the thin layer A and the anode electrode, and the target composition and target layer shown in Table 3 are formed on the surface of the tool base. A thick underlayer is deposited.
(D) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table. An arc discharge is generated by flowing a predetermined current in the range of 50 to 200 A between the cathode electrode and the anode electrode of the Al—Ti—Si alloy for forming the thin layer B, and on the tool base (the underlying layer). After that, a thin layer B having a predetermined thickness is formed, and then a predetermined current in the range of 50 to 200 A is passed between the cathode electrode and the anode electrode of the Al—Ti—Si alloy for forming the base layer and the thin layer A. After arc discharge is generated to form the thin layer A having a predetermined thickness, the thin layer B and the thin layer A are alternately and repeatedly formed.
According to the procedures (a) to (d), the base layer having the target composition and target layer thickness shown in Table 2 and the thin layer A having the target composition and target thickness shown in Table 2 are formed on the surface of the tool base. The coated chips 1 to 5 of the present invention as the coated tool of the present invention in the form of a throwaway tip defined in ISO · CNMG120408 were produced by vapor deposition of the upper layer composed of the alternating layers of the thin layer B and the thin layer B, respectively.

For comparison purposes, these tool bases A-1 to A-5 were ultrasonically cleaned in acetone and dried, and then loaded into the arc ion plating apparatus shown in FIG. As the (evaporation source), an Al—Cr—Si alloy and an Al—Ti alloy each having a component composition corresponding to the target composition shown in Table 3 were mounted,
First, while evacuating the inside of the apparatus and maintaining the vacuum at 0.5 Pa or less, the inside of the apparatus was heated to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the tool base, and the cathode electrode An arc discharge is generated by passing a current of 100 A between the Al—Cr—Si alloy (or Al—Ti alloy) and the anode electrode, so that the surface of the tool base is made of the Al—Cr—Si alloy (or Al—Ti alloy). )
Next, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 2 Pa, and the bias voltage applied to the tool base is lowered to −100 V, and the Al—Cr—Si alloy (or Al—Ti alloy) is used. An arc discharge is generated between the cathode electrode and the anode electrode, and the (Al, Cr, Si) N layer (or Table 3) having the target composition and target layer thickness shown in Table 3 is formed on the surface of the tool base. (Al, Ti) N layer) having the target composition and target layer thickness shown in FIG.
Then, an arc discharge is generated between the cathode electrode and the anode electrode of the Al—Ti alloy (or Al—Cr—Si alloy), and the target composition and target layer shown in Table 3 are formed on the surface of the tool base. A (Al, Ti) N layer having a thickness (or an (Al, Cr, Si) N layer having a target composition and a target layer thickness shown in Table 3) is formed by vapor deposition.
By alternately repeating the deposition formation of the (Al, Cr, Si) N layer and the (Al, Ti) N layer, a hard coating layer having an alternate lamination of the target composition and the target layer thickness shown in Table 3 is provided. Then, comparative coated tips 1 to 5 as a comparative coated tool having a throwaway tip shape defined in ISO · CNMG120408 were manufactured.

Next, in the state where each of the above various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1 to 5 and the conventional coated chips 1 to 5 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: 80 m / min. ,
Cutting depth: 2.0 mm,
Feed: 0.3 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: 60 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.20 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 25 m / min.),
In each cutting test, the flank wear width of the cutting edge was measured. The measurement results are shown in Table 4.

As raw material powders, WC powder having an average particle size of 0.8 μm, 1.3 μm TaC powder, 1.2 μm NbC powder, 1.2 μm ZrC powder, 2.3 μm Cr ₃ C ₂ powder, Prepare 1.5 μm VC powder and 1.8 μm Co powder, mix these raw material powders with the blending composition shown in Table 5, add wax and ball mill mix in acetone for 24 hours, and dry under reduced pressure After that, it was press-molded into various green compacts of a predetermined shape at a pressure of 100 MPa, and these green compacts were in a range of 1370 to 1470 ° C. at a temperature increase rate of 7 ° C./min in a 6 Pa vacuum atmosphere. The temperature is raised to a predetermined temperature, held at this temperature for 1 hour, and then sintered under furnace cooling conditions to form a round bar sintered body for forming a tool base. Further, the round bar sintered body is ground. In processing, the diameter x length of the cutting edge shown in Table 5 Produced WC-based cemented carbide tool bases (end mills) C-1 to C-4 having a size of 10 mm × 22 mm and a four-blade square shape with a twist angle of 45 degrees.

  Next, the surfaces of these tool bases (end mills) C-1 to C-4 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, along the layer thickness direction, the target composition and the underlayer having the target layer thickness shown in Table 6 and the thin layers A and B having the target composition and the target layer thickness also shown in Table 6 The coated end mills 1 to 4 of the present invention as the coated tool of the present invention were produced by vapor-depositing upper layers composed of alternating layers.

  For the purpose of comparison, the surfaces of the tool bases (end mills) C-1 to C-4 are ultrasonically cleaned in acetone and dried, and then mounted on the arc ion plating apparatus shown in FIG. Then, under the same conditions as in Example 1, the (Al, Cr, Si) N layer having the target composition and target layer thickness shown in Table 7 is formed on the surface of the tool base (end mill) C-1 to C-4. Comparative coating end mills 1 to 4 as comparative coating tools were manufactured by vapor-depositing hard coating layers composed of alternating layers of and (Al, Ti) N layers.

Next, the present invention coated end mills 1-4 and comparative coated end mills 1-4,
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): 3 mm,
Table feed: 300 mm / min,
Ni-base alloy dry high-speed grooving test under the conditions (normal cutting speed and groove depth are 25 m / min. And 1.2 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 6 and 7, respectively.

  Using the round bar sintered body manufactured in Example 2 above, from this round bar sintered body, the diameter x length of the groove forming portion is 8 mm x 48 mm and the helix angle is 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. And under the same conditions as in Example 1 above, the underlayer of the target composition and target layer thickness shown in Table 8 and the thin layer of the target composition and target thickness shown in Table 8 along the layer thickness direction. The coated drills 1 to 4 of the present invention as the coated tools of the present invention were produced by vapor-depositing and forming upper layers composed of alternating layers of A and thin layers B, respectively.

  For the purpose of comparison, the surface of the tool base (drill) D-1 to D-4 is 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 above, the target composition and target layer thickness (Al, Cr) shown in Table 9 are formed on the surfaces of the tool bases (drills) D-1 to D-4. , Si) N layers and (Al, Ti) N layers were vapor deposited to form a hard coating layer, thereby producing comparative coated drills 1 to 4 as comparative coated tools.

Next, for the present invention coated drills 1-8 and comparative coated drills 1-4,
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: 45 m / min. ,
Feed: 0.30 mm / rev,
Hole depth: 20 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 8 and 9, respectively.

  As a result of the present invention coated tool as the present invention coated tool 1-5, the present invention coated end mills 1-4 and the present invention coated drills 1-4 constituting the hard coating layer, the thin layer A and the thin layer An upper layer composed of an alternately laminated structure of layers B, and further, a hard coating layer composed of alternate laminations of comparative coated tips 1 to 5, comparative coated end mills 1 to 4 and comparative coated drills 1 to 4 (Al, Cr, Si) ) The composition of the N layer and the (Al, Ti) N layer was measured by energy dispersive X-ray analysis using a transmission electron microscope, and each showed substantially the same composition as the target composition.

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

  From the results shown in Tables 4 and 6 to 9, the coated tool of the present invention has an excellent hard coating layer in which the hard coating layer is composed of an upper layer composed of an alternating layer structure of an underlayer, thin layer A, and thin layer B. High-temperature hardness, high-temperature toughness, high-temperature strength, heat-resistant plastic deformability, as well as excellent high-temperature oxidation resistance and interlayer adhesion strength. Even when it is used for cutting under high-speed conditions, the hard coating layer (Al, Cr, In comparative coated tools composed of alternating layers of Si) N layers and (Al, Ti) N layers, especially in high-speed cutting of heat-resistant alloys such as Ni-base alloys and Co-base alloys, chipping resistance and fracture resistance Due to lack of performance, the service life is reached in a relatively short time. Bet is clear.

  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. Because it exhibits excellent wear resistance over a long period of time and exhibits excellent cutting performance, it is sufficiently satisfied with the FA of cutting equipment, labor saving and energy saving of cutting work, and further cost reduction It can respond.

The arc ion plating apparatus used for forming the hard coating layer which comprises the coating tool of this invention is shown, (a) is a schematic plan view, (b) is a schematic front view. The arc ion plating apparatus used for forming the hard coating layer which comprises a comparative coating tool is shown, (a) is a schematic plan view, (b) is a schematic front view.

Claims (1)

A surface-coated cutting tool in which a hard coating layer composed of an underlayer and an upper layer is vapor-deposited on the surface of a tool substrate,
(A) The underlayer has a layer thickness of more than 0.05 μm and 2 μm or less, and
Composition _{formula: [Al X Cr Y Si Z} ] N
X, Y, Z (all atomic ratios) indicating the content ratios of Al, Cr, Si are 0.45 ≦ X ≦ 0.70, 0.25 ≦ Y ≦ 0.50, 0 .02 ≦ Z ≦ 0.15, a composite nitride layer of Al, Cr and Si satisfying X + Y + Z = 1,
(B) Each of the upper layers has an alternately laminated structure of a thin layer A and a thin layer B each having an average layer thickness of 0.005 to 0.05 μm, and the total of the thin layer A and the thin layer B. The layer thickness is 1-5 μm,
(C) The thin layer A is
Composition _{formula: [Al X Cr Y Si Z} ] N
X, Y, Z (all atomic ratios) indicating the content ratios of Al, Cr, Si are 0.45 ≦ X ≦ 0.70, 0.25 ≦ Y ≦ 0.50, 0 .02 ≦ Z ≦ 0.15, a composite nitride layer of Al, Cr and Si satisfying X + Y + Z = 1,
(D) The thin layer B is
Composition _{formula: [Al U Ti V Si W} ] N
, U, V, and W (all atomic ratios) indicating the content ratios of Al, Ti, and Si are 0.40 ≦ U ≦ 0.65, 0.30 ≦ V ≦ 0.55, 0 .02 ≦ W ≦ 0.15 and a composite nitride layer of Al, Ti and Si satisfying U + V + W = 1.
A surface-coated cutting tool characterized by that.

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