JP4771199B2 - Surface-coated cermet cutting tool with excellent wear resistance due to high-speed cutting of heat-resistant alloys - Google Patents

Description

This invention has excellent heat resistance in the hard coating layer, and therefore, especially when heat-resistant steel, Co alloy, and heat-resistant alloys such as Ni alloy are cut under high-speed cutting conditions with high heat generation. The surface coating cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent wear resistance over a long period of time without the occurrence of thermoplastic deformation that causes uneven wear that accelerates the progress of wear in the hard coating layer. ).

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

Further, as a coated cermet tool, on the surface of a cermet base (hereinafter simply referred to as a base) composed of a tungsten carbide (hereinafter referred to as WC) base cemented carbide or a titanium carbonitride (hereinafter referred to as TiCN) base cermet, Having a single phase structure, and
_{Formula: [Ti 1- (X + Y} ) Al X Cr Y] N ( provided that an atomic ratio, X is 0.45 to 0.65, Y represents a 0.01 to 0.15),
A coated cermet tool formed by vapor-depositing a hard coating layer composed of a composite nitride of Ti, Al, and Cr [hereinafter referred to as (Ti, Al, Cr) N] layer satisfying the following conditions with an average layer thickness of 2 to 8 μm: The (Ti, Al, Cr) N layer is known to have high temperature hardness and high temperature oxidation resistance due to Al as a component, high temperature strength due to the Ti, and heat resistance improved due to the Cr. It is also known to do.

Furthermore, the above coated cermet tool, is charged with an arc ion plating apparatus of the above base is one of physical vapor deposition apparatus shown in example schematic diagram in FIG. 2, in the apparatus with a heater, for example, 500 ° C. An arc discharge is generated between the anode electrode and the cathode electrode (evaporation source) on which a Ti—Al—Cr alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of by introduction of nitrogen gas as a reaction gas into the apparatus, for example, a reaction atmosphere of 2 Pa, whereas the said substrate, for example under the conditions of applying a bias voltage of -100 V, the surface of the substrate, the (Ti, Al, It is also known to be produced by vapor-depositing a hard coating layer consisting of a Cr) N layer.
JP-A-7-237010

In recent years, the performance of cutting devices has been dramatically improved, while on the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and with this, cutting tends to be faster. In coated cermet tools, when used for cutting high-speed cutting conditions such as carbon steel, low-alloy steel, and ordinary cast iron, normal cutting performance is not a problem. When heat-resistant alloys such as Ni alloy, Co alloy, and Ni alloy are used for cutting under high-speed cutting conditions, heat generation during cutting is significant, and a hard coating layer (Ti, Al, Cr) In the N layer, thermoplastic deformation occurs due to insufficient heat resistance, and this causes uneven wear. As a result, wear progresses rapidly, and as a result, wear life is relatively short. Is the current situation That.

In view of the above, the present inventors have developed a coated cermet tool in which the hard coating layer takes a normal wear form especially in high-speed cutting of the above heat-resistant alloy and exhibits excellent wear resistance over a long period of time. As a result of conducting research by focusing on the (Ti, Al, Cr) N layer that constitutes the hard coating layer of the conventional coated cermet tool,
(A) In the (Ti, Al, Cr) N layer constituting the hard coating layer, the heat resistance improves as the Cr component content increases, but the conventional (Ti, Al, Cr) ) When the Cr content is about 1 to 15 atomic% in the N layer, the heat resistant alloy cannot be provided with heat resistance sufficient to prevent the occurrence of thermoplastic deformation in high-speed cutting with high heat generation. In order to ensure excellent heat resistance that does not cause thermoplastic deformation in the high-speed cutting process, it is necessary to contain 40-60 atomic% of Cr far exceeding 1-15 atomic%, while 40-60 In order to practically use a (Ti, Al, Cr) N layer containing an atomic% Cr component as a hard coating layer, it is necessary to contain a predetermined amount of Ti to ensure a predetermined high-temperature strength. In this case, the Al component content is Wamete inevitably become low state, as a result high-temperature hardness and shall become possible high temperature oxidation resistance of very low.

(B) Composition formula: (Ti _{1- (A + B)} Al _A Cr _B ) N (provided that A is 0.01 to 0.10 and B is 0.40 to 0.60 in atomic ratio) A (Ti, Al, Cr) N layer having a Cr content of 40 to 60 atomic%;
A compositional formula: (Ti _{1− (C + D)} Al _C Cr _D ) N (wherein, C is 0.20 to 0.35 and D is 0.15 to 0.30 in an atomic ratio), relative (Ti, Al, Cr) N layer with a large content ratio of Al component,
Are alternately laminated in a state where each layer has an average layer thickness of 5 to 20 nm (nanometers), and the resulting (Ti, Al, Cr) N layer has a thin laminated structure, The excellent heat resistance of the (Ti, Al, Cr) N layer (hereinafter referred to as the thin layer A) having a high Cr content, and a relatively low Cr content ratio compared to the thin layer A, (Ti, Al, Cr) N layer (hereinafter referred to as thin layer B) having a high Al content ratio has relatively high high temperature hardness and high temperature oxidation resistance.

(C) The (Ti, Al, Cr) N layer having the alternate layered structure of the thin layer A and the thin layer B of (b) above has excellent heat resistance required for high-speed cutting of heat-resistant alloys. Since it does not have a sufficiently satisfactory high-temperature hardness and high-temperature oxidation resistance, it is provided as an upper layer of the hard coating layer, while the lower layer does not have sufficient heat resistance, but relatively Al components (Ti, Al, Cr) N layer having a composition corresponding to the above-described conventional hard coating layer having a high content ratio, excellent high temperature hardness and high temperature oxidation resistance,
_{Formula: [Ti 1- (E + F} ) Al E Cr F] N ( provided that an atomic ratio, E is 0.45 to 0.65, F represents a 0.01 to 0.15) satisfies the single (Ti, Al, Cr) N layer of single phase structure,
The resulting hard coating layer has a combination of high-temperature hardness, high-temperature oxidation resistance, and high-temperature strength in addition to excellent heat resistance. The coated cermet tool formed by vapor deposition of the above heat-resistant alloy is free from the occurrence of thermoplastic deformation causing uneven wear in the hard coating layer even in high-speed cutting with high heat generation, so that it takes a normal wear form. As a result, excellent wear resistance will be demonstrated over a long period of time.
The research results shown in (a) to (c) above were obtained.

This invention has been made based on the above research results, and on the surface of the substrate ,
(A) Both are composed of an upper layer and a lower layer made of (Ti, Al, Cr) N, the upper layer has a layer thickness of 0.5 to 1.5 μm, and the lower layer has a layer thickness of 2 to 6 μm. ,
(B) Each of the upper layers has an alternately laminated structure of thin layers A and B having a layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
_{Formula: [Ti 1- (A + B} ) Al A Cr B] N ( provided that an atomic ratio, A is 0.01 to 0.10, B represents a 0.40 to 0.60) satisfies (Ti , Al, Cr) N layer,
The thin layer B is
Composition formula: [Ti _{1− (C + D)} Al _C Cr _D ] N (wherein C is 0.20 to 0.35 and D is 0.15 to 0.30 in atomic ratio) (Ti , Al, Cr) N layer,
(C) the lower layer has a single phase structure;
Composition formula: [Ti _{1− (E + F)} Al _E Cr _F ] N (wherein E is 0.45 to 0.65 and F is 0.01 to 0.15 in atomic ratio) (Ti , Al, Cr) N layer,
It is characterized by a coated cermet tool that exhibits excellent wear resistance in high-speed cutting of a heat-resistant alloy, formed by vapor-depositing a hard coating layer comprising:

Next, the reason why the numerical values of the hard coating layer of the coated cermet tool of the present invention are limited as described above will be described.
(A) Composition formula and layer thickness of lower layer As described above, the Al component in the (Ti, Al, Cr) N layer constituting the hard coating layer improves the high temperature hardness and high temperature oxidation resistance, while the same Ti The component has the effect of improving the high-temperature strength and the Cr component, and the heat resistance of the Cr component.In the lower layer, the overall content of the Al component is increased to provide high high-temperature hardness and high-temperature oxidation resistance. When the E value indicating the Al content is less than 0.45 in the total amount of Ti and Cr (atomic ratio, the same applies hereinafter), excellent high temperature required for high-speed cutting of heat-resistant alloys with extremely high heat generation Hardness and high-temperature oxidation resistance cannot be ensured, and wear progresses rapidly. On the other hand, when the E value indicating the Al ratio exceeds 0.65, the high-temperature strength decreases rapidly. As a result, chipping (slight chipping) occurs. Since it becomes easy to produce, E value was determined as 0.45-0.65.
Further, if the F value indicating the ratio of Cr is the ratio of the total amount of Ti and Al, and less than 0.01, the predetermined minimum heat resistance cannot be ensured, while the F value is 0.15. Exceeds the above-mentioned excellent characteristics of the lower layer, that is, high-temperature hardness, high-temperature oxidation resistance, and high-temperature strength suddenly decrease, so the F value is set to 0.01 to 0.15. It was.
Furthermore, if the layer thickness is less than 2 μm, the excellent high-temperature hardness and high-temperature oxidation resistance cannot be imparted to the hard coating layer over a long period of time, resulting in short tool life, while the layer thickness is 6 μm. If it exceeds, chipping is likely to occur, so the layer thickness was determined to be 2 to 6 μm.

(B) Composition formula of thin layer A of the upper layer The Cr component in (Ti, Al, Cr) N of the thin layer A of the upper layer is as high as possible to improve the heat resistance as described above. Therefore, it is contained for the purpose of improving the heat-resistant plastic deformation property in high-speed cutting of a heat-resistant alloy accompanied by high heat generation. Therefore, if the B value is less than 0.40, desired excellent heat resistance can be secured. On the other hand, if the B value exceeds 0.60, the content ratio of the Ti component is relatively reduced, and the high-temperature strength that the layer itself should have can be secured, which causes chipping. Therefore, the B value was set to 0.40 to 0.60.
Further, the A value indicating the proportion of Al is the proportion of the total amount of Ti and Cr, and if it is less than 0.01, the minimum high-temperature hardness and high-temperature oxidation resistance cannot be ensured, and the cause of accelerated wear On the other hand, if the A value exceeds 0.10, the high-temperature strength suddenly decreases and chipping is likely to occur. Therefore, the A value was determined to be 0.01 to 0.10.

(C) Composition formula of thin layer B of the upper layer In the thin layer B of the upper layer, the content ratio of the Cr component is relatively lower than that of the thin layer A, and the content ratio of the Al component is relatively By keeping the thin layer A high, the thin layer A has insufficient high-temperature hardness and high-temperature oxidation resistance, reinforces high-temperature hardness and high-temperature oxidation resistance of the adjacent thin layer A, The upper layer having the excellent heat resistance of the layer A and the relatively high high temperature hardness and high temperature oxidation resistance of the thin layer B is formed, and the Al content in the composition formula is shown. When the C value is less than 0.20, the predetermined relatively high high temperature hardness and high temperature oxidation resistance cannot be ensured, and the progress of wear is promoted, while the C value is 0.35. If this is exceeded, a drop in the high-temperature strength of the entire upper layer is inevitable, and chipping occurs For this reason, the C value was set to 0.20 to 0.35.
Further, the D value indicating the ratio of Cr is the ratio of the total amount of Ti and Al, and if it is less than 0.15, the heat resistance of the entire upper layer is inevitably lowered, while the D value exceeds 0.30. Then, since the high-temperature strength of the entire upper layer suddenly decreases, the D value was set to 0.15 to 0.30.

(D) Layer thicknesses of upper layer thin layer A and layer B If each layer thickness is less than 5 nm, it is difficult to form each thin layer clearly with the above composition. It is impossible to ensure excellent heat resistance, and a predetermined relatively high high-temperature hardness and high-temperature oxidation resistance. Further, when the thickness of each layer exceeds 20 nm, the disadvantage of each thin layer, that is, the thin layer A If there is insufficient high-temperature hardness and high-temperature oxidation resistance, and if it is thin layer B, insufficient heat resistance will appear locally in the layer, which may cause chipping or promote wear progress. Each layer thickness was determined to be 5 to 20 nm.

(E) Layer thickness of the upper layer If the layer thickness is less than 0.5 μm, it is impossible to provide the hard coating layer with its excellent heat resistance and predetermined high temperature hardness and high temperature oxidation resistance over a long period of time. On the other hand, if the layer thickness exceeds 1.5 μm, chipping tends to occur. Therefore, the layer thickness is set to 0.5 to 1.5 μm.

In the coated cermet tool of the present invention, the hard coating layer is composed of a (Ti, Al, Cr) N layer, and the upper layer of the hard coating layer has an alternate laminated structure of the thin layer A and the thin layer B. High heat hardness and high temperature oxidation resistance are maintained, and excellent heat resistance is provided, and the lower layer of the single phase structure has relatively high high temperature hardness and high temperature oxidation resistance. Even in high-speed cutting with high heat generation of heat-resistant alloys such as Ni alloy, Co alloy, and Ni alloy, the thermoplastic coating of the hard coating layer is remarkably suppressed, and excellent wear resistance is exhibited over a long period of time. It is.

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

As raw material powders, WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder each having a predetermined average particle diameter in the range of 1 to 3 μm, And Co powder, these raw material powders are blended in the composition shown in Table 1, wet mixed for 72 hours by a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa. The body was sintered in a vacuum of 6 Pa at a temperature of 1400 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to have a chip shape of ISO standard / CNMG120408. It was to form a WC-based cemented carbide substrate a-1 to a-10 of.

Further, as raw material powders, TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, all having a predetermined average particle diameter in the range of 0.5 to 2 μm, TaC powder, WC powder, Co powder, and Ni powder are prepared. These raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then compacted at a pressure of 100 MPa. The green compact was pressed into a body and sintered in a 2 kPa nitrogen atmosphere at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge was subjected to a honing process of R: 0.03. to form a TiCN based cermet substrate B-1 to B-6 having a tip shape of ISO standard · CNMG120408 Te.

(A) Next, each of the substrates A-1 to A-10 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, and then the arc ion plating apparatus shown in FIG. Attached along the outer periphery at a predetermined distance in the radial direction from the central axis on the inner rotary table, and corresponded to the target compositions shown in Tables 3 and 4 as cathode electrodes (evaporation sources) on one side, respectively. The Ti-Al-Cr alloy for forming the upper layer thin layer A having the component composition and the cathode electrode (evaporation source) on the other side also had component compositions corresponding to the target compositions shown in Tables 3 and 4, respectively. A Ti-Al-Cr alloy for forming the thin layer B as an upper layer is disposed opposite to the rotary table, and a cathode electrode (along the rotary table at a position shifted by 90 degrees from both the Ti-Al-Cr alloys. Evaporation source) The Ti-Al-Cr alloy for the lower layer formed is attached,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then the direct current of −1000 V is applied to the base that rotates while rotating on the rotary table A bias voltage is applied, and a current of 100 A is passed between the Ti-Al-Cr alloy for forming the lower layer and the anode electrode to generate an arc discharge, whereby the substrate surface is bombarded by the Ti-Al-Cr alloy. Wash and
(C) Introducing nitrogen gas as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, applying a DC bias voltage of −100 V to the substrate rotating while rotating on the rotary table, and forming the lower layer A current of 100 A is passed between the Ti-Al-Cr alloy for an anode and the anode electrode to generate an arc discharge, so that a single phase having a target composition and a target layer thickness shown in Tables 3 and 4 is formed on the surface of the substrate. (Ti, Al, Cr) N layer having a structure is deposited as a lower layer of the hard coating layer,
(D) Next, nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 2 Pa, and the thin substrate is applied in a state where a DC bias voltage of −100 V is applied to the substrate rotating while rotating on the rotary table. A predetermined current within a range of 50 to 200 A is passed between the cathode electrode and the anode electrode of the Ti-Al-Cr alloy for forming layer A to generate arc discharge, and a thin layer having a predetermined layer thickness is formed on the surface of the substrate. After forming the layer A, the arc discharge is stopped after the thin layer A is formed, and instead, the cathode layer and the anode electrode of the Ti-Al-Cr alloy for forming the thin layer B are also within the range of 50 to 200A. An arc discharge is generated by flowing a predetermined current to form a thin layer B having a predetermined layer thickness, and then the arc discharge is stopped (in this case, the formation of the thin layer B may be started), and the thin layer is again formed. A-forming Ti-Al-C The formation of the thin layer A by arc discharge between the cathode electrode and the anode electrode of the alloy and the formation of the thin layer B by arc discharge between the cathode electrode and the anode electrode of the Ti-Al-Cr alloy for forming the thin layer B are alternately performed. Repeatedly, on the surface of the substrate , an upper layer composed of alternating layers of the thin layer A and the thin layer B having the target composition and the single target layer thickness shown in Tables 3 and 4 along the layer thickness direction is also shown in Table 3, The surface-coated cermet throwaway tips (hereinafter referred to as the present invention-coated tips ) 1 to 16 as the present invention-coated cermet tools were produced by vapor deposition with the overall target layer thickness shown in FIG.

For comparison purposes, these substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plating apparatus shown in FIG. A Ti—Al—Cr alloy having a component composition corresponding to the target composition shown in Table 5 was attached as a cathode electrode (evaporation source), and the apparatus was first evacuated to 0.1 Pa. While maintaining the following vacuum, the inside of the apparatus was heated to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the substrate , and the Ti—Al—Cr alloy of the cathode electrode and the anode electrode were by flowing a 100A current to generate an arc discharge, it has bombarded washed substrate surface in the Ti-Al-Cr alloy, and then reaction of 3Pa by introducing nitrogen gas as a reaction gas into the apparatus cut With the gas, lowering the bias voltage applied to the substrate to -100 V, the cause arcing between the cathode electrode and the anode electrode of Ti-Al-Cr alloy, wherein with the substrate A-1 to A A hard coating layer composed of a (Ti, Al, Cr) N layer having a single-phase structure having a target composition and a target layer thickness shown in Table 5 is deposited on each surface of -10 and B-1 to B-6. By forming, comparative surface-coated cermet throwaway tips (hereinafter referred to as comparative coated tips ) 1 to 16 as comparative coated cermet tools corresponding to conventional coated cermet tools were produced, respectively.

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 1-16 and the comparative coated chips 1-16,
Work material: JIS / SUH31 round bar,
Cutting speed: 200 m / min. ,
Cutting depth: 2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 15 minutes,
Dry continuous high-speed cutting test of heat-resistant steel under the conditions (cutting condition A) (normal cutting speed is 100 m / min.),
Work material: Round bar with four longitudinal grooves at equal intervals in the length direction of Co alloy having a composition of Co-25.5% Cr-7.5% W-10.5% Ni in mass%.
Cutting speed: 100 m / min. ,
Cutting depth: 1mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed cutting test of Co alloy under the conditions (cutting condition B) (normal cutting speed is 50 m / min.),
Work material: Ni alloy round bar with a composition of Ni-15.5% Cr-0.9% Co-8% Fe in mass%,
Cutting speed: 90 m / min. ,
Cutting depth: 2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
The dry continuous high-speed cutting test (normal cutting speed is 40 m / min.) Of the Ni alloy under the above conditions (cutting condition C) was performed, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 6.

As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [by mass ratio, TiC / WC = 50/50] powder, and 1 Prepare 8 .mu.m Co powder, mix these raw material powders with the composition shown in Table 7, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and then press at a pressure of 100 MPa. The green compacts were press-molded, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions , 8 mm in diameter, 13 mm, and 26mm to form a three base-forming rod sintered body, the further three round bar sintered body of said at grinding, in combinations shown in Table 7 A base made of a WC-base cemented carbide having a four-blade square shape with a diameter × length of the cutting edge of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, respectively, and a twist angle of 30 degrees. (End mill) C-1 to C-8 were produced.

Then, the surfaces of these substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. 1 under the same conditions as in No. 1, and a lower layer composed of a (Ti, Al, Cr) N layer having a single phase structure with the target composition and target layer thickness shown in Table 8, and Table 8 along the layer thickness direction. A book as a coated cermet tool of the present invention is formed by vapor-depositing an upper layer composed of alternating layers of thin layer A and thin layer B having a target composition and a single target layer thickness with the overall target layer thickness shown in Table 8 as well. Invention surface coated cermet end mills (hereinafter referred to as the present invention coated end mills ) 1 to 8 were produced.

For comparison purposes, the surfaces of the substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then loaded into the arc ion plating apparatus shown in FIG. By depositing a hard coating layer comprising a (Ti, Al, Cr) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 9 under the same conditions as in Example 1 above. Comparative surface-coated cermet end mills (hereinafter referred to as comparative coated end mills ) 1 to 8 as comparative coated cermet tools corresponding to conventional coated cermet tools were produced, respectively.

Next, of the present invention coated end mills 1-8 and comparative coated end mills 1-8, the present invention coated end mills 1-3 and comparative coated end mills 1-3 are as follows:
Work material-plane: 100 mm × 250 mm, thickness: 50 mm Ni alloy plate of the above composition (mass%, Ni-15.5% Cr-0.9% Co-8% Fe),
Cutting speed: 70 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 280 mm / min,
The dry high-speed grooving test of Ni alloy under the conditions (normal cutting speed is 30 m / min.), The coated end mills 4 to 6 and the comparative coated end mills 4 to 6 of the present invention ,
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm plate material of JIS / SUH31,
Cutting speed: 100 m / min. ,
Groove depth (cut): 4 mm
Table feed: 500 mm / min,
With respect to the heat-resistant steel dry high-speed grooving test (normal cutting speed is 50 m / min.), The coated end mills 7 and 8 of the present invention and the comparative coated end mills 7 and 8
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm Co alloy of the above composition (mass%, Co-25.5% Cr-7.5% W-10.5% Ni) Board,
Cutting speed: 60 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 150 mm / min,
The dry high-speed grooving test of Co alloy under the conditions (normal cutting speed is 30 m / min.) Is performed, and the flank wear width of the outer peripheral edge of the cutting edge is the service life in any grooving test. The cutting groove length up to 0.1 mm as a standard was measured. The measurement results are shown in Tables 8 and 9, respectively.

The diameter prepared in Example 2 of 8 mm (for substrates C-1 through C-3 form), 13 mm (for substrates C-4~C-6 form), and 26 mm (base C-7, C-8 form with three round bar sintered body use), from the three round bar sintered at grinding, diameter × length of the groove forming portions respectively 4 mm × 13 mm (base D-1 to D -3), 8mm × 22mm (base D-4~D-6), and dimensions of 16 mm × 45 mm (base D-7, D-8) , and both with a two-blade shape of the twist angle of 30 degrees Substrates (drills) D-1 to D-8 made of WC-base cemented carbide were produced.

Next, the cutting edges of these substrates (drills) D-1 to D-8 are subjected to honing, 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 lower layer composed of a (Ti, Al, Cr) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 10, and also in the layer thickness direction In accordance with the present invention, the upper layer composed of alternating layers of the thin layer A and the thin layer B having the target composition shown in Table 10 and a single target layer thickness is formed by vapor deposition with the overall target layer thickness shown in Table 10 as well. The surface-coated cermet drills according to the present invention (hereinafter referred to as the present invention-coated drills ) 1 to 8 as coated cermet tools were produced, respectively.

For comparison purposes, the surfaces of the substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried, and the arc ion plate shown in FIG. A hard coating layer comprising a (Ti, Al, Cr) N layer having a single phase structure with the target composition and target layer thickness shown in Table 11 under the same conditions as in Example 1 above. The surface-coated cermet drills (hereinafter referred to as comparative coated drills ) 1 to 8 as comparative coated cermet tools corresponding to conventional coated cermet tools were produced.

Next, of the present invention coated drills 1-8 and comparative coated drills 1-8, for the present invention coated drills 1-3 and comparative coated drills 1-3,
Work material-Plane: 100 mm × 250, thickness: 50 mm Co alloy of the above composition (mass%, Co-25.5% Cr-7.5% W-10.5% Ni) Board,
Cutting speed: 50 m / min. ,
Feed: 0.1 mm / rev,
Hole depth: 6mm,
For the Co alloy wet high-speed drilling test (normal cutting speed is 20 m / min.), The inventive coated drills 4 to 6 and the comparative coated drills 4 to 6
Work material-plane: 100 mm × 250 mm, thickness: 50 mm Ni alloy plate of the above composition (mass%, Ni-15.5% Cr-0.9% Co-8% Fe),
Cutting speed: 70 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 15mm,
With respect to the Ni alloy wet high speed drilling cutting test (normal cutting speed is 30 m / min.), The present invention coated drills 7 and 8 and the comparative coated drills 7 and 8,
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm plate material of JIS / SUH31,
Cutting speed: 100 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 30mm,
Wet high-speed drilling test of heat-resistant steel under normal conditions (normal cutting speed is 50 m / min.), And any wet high-speed drilling test (using water-soluble cutting oil) The number of drilling processes until the flank wear width reached 0.3 mm was measured. The measurement results are shown in Table 8, respectively.

Hard coating layer made of (Ti, Al, Cr) N of the present coated chips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated cermet tool obtained as a result. Thin layer A and thin layer B of the upper layer, and the composition of the lower layer, and comparative coated tips 1-16, comparative coated end mills 1-8 as comparative coated cermet tools corresponding to conventional coated cermet tools, and The composition of the hard coating layer made of (Ti, Al, Cr) N of the comparative coated drills 1 to 8 was measured by energy dispersive X-ray analysis using a transmission electron microscope. Showed the same composition.

  Further, when the average layer thickness of the constituent layers of the hard coating layer was subjected to cross-sectional measurement using a transmission electron microscope, all showed the same average value (average value of five locations) as the target layer thickness.

From the results shown in Tables 3 to 11, each of the coated cermet tools of the present invention has a single-phase structure lower layer composed of (Ti, Al, Cr) N, each having a hard coating layer having a different composition, and a layer thickness. Each layer is composed of an upper layer having an alternating layered structure of thin layers A and thin layers B of 5 to 20 nm, the lower layer has excellent high temperature hardness and oxidation resistance, and the upper layer has excellent heat resistance. In addition, since the hard coating layer has these excellent characteristics comprehensively, especially when used for high-speed cutting with high heat generation of heat-resistant alloys such as heat-resistant steel, Co alloy, and Ni alloy, Since the hard coating layer exhibits excellent heat-resistant plastic deformation, cutting is performed while taking a normal wear form. As a result, the hard coating layer exhibits excellent wear resistance. (Ti of single phase structure Al, the comparative coated cermet tool composed of Cr) N layer, in the high speed machining of heat resistant alloys, the heat resistance insufficient hard layer thermal plastic deformation caused by, is avoided cutting in uneven wear form From this, it is clear that the progress of wear is further accelerated, and as a result, the service life is reached in a relatively short time.

As described above, the coated cermet tool of the present invention is accompanied not only by cutting under high-speed cutting conditions such as various carbon steels, low alloy steels, and even ordinary cast iron, but particularly with high heat generation of heat resistant alloys. Excellent wear resistance even during high-speed cutting, excellent cutting performance over a long period of time, and versatility for work materials. In addition, it can cope with the cost reduction sufficiently satisfactorily.

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

Claims (1)

On the surface of the cermet substrate composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) Both are composed of an upper layer and a lower layer made of a composite nitride of Ti, Al, and Cr. The upper layer has a layer thickness of 0.5 to 1.5 μm, and the lower layer has a layer thickness of 2 to 6 μm. And
(B) Each of the upper layers has an alternately laminated structure of thin layers A and B having a layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
Ti satisfying the composition formula: [Ti _{1− (A + B)} Al _A Cr _B ] N (wherein A represents 0.01 to 0.10 and B represents 0.40 to 0.60) A composite nitride layer of Al and Cr;
The thin layer B is
_{Formula: [Ti 1- (C + D} ) Al C Cr D] N ( provided that an atomic ratio, C is 0.20 to 0.35, D denotes the 0.15 to 0.30) and Ti which satisfies A composite nitride layer of Al and Cr,
(C) the lower layer has a single phase structure;
Ti satisfying the composition formula: [Ti _{1− (E + F)} Al _E Cr _F ] N (wherein E is 0.45 to 0.65 and F is 0.01 to 0.15 in atomic ratio) A composite nitride layer of Al and Cr;
A surface-coated cermet cutting tool that exhibits excellent wear resistance in high-speed cutting of heat-resistant alloys, formed by vapor-depositing a hard coating layer made of

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