JP2006281409A - Surface coated cemented carbide cutting tool with hard coating layer exerting excellent wear resistance in high-speed cutting of high hardness steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide cutting tool with a hard coating layer exerting excellent wear resistance in high-speed cutting of high hardness steel. <P>SOLUTION: The surface coated cemented carbide cutting tool is composed by forming the hard coating layer on the surface of a cemented carbide base body by vapor deposition. The hard coating layer is composed of an upper layer with an average layer thickness of 0.5-1.5 μm and a lower layer with an average layer thickness of 2-6 μm respectively comprising nitride compound of Ti, Al, and Zr. The upper layer has an alternately laminated structure of a thin layer (A) and a thin layer (B) respectively having an average layer thickness of 5-20 nm (nanometers) per layer. The thin layer (A) is composed of a layer of the nitride compound of Ti, Al, and Zr satisfying formula: [Ti<SB>1-(A+B)</SB>Al<SB>A</SB>Zr<SB>B</SB>]N (where, (A) represents 0.01-0.06 and (B) represents 0.35-0.55 by atomic ratio). The thin layer (B) is composed of a layer of the nitride compound of Ti, Al, and Zr satisfying composition formula: [Ti<SB>1-(C+D)</SB>Al<SB>C</SB>Zr<SB>D</SB>] N (where, C represents 0.20-0.35 and D represents 0.20-0.30 by atomic ratio). The lower layer has a single layer structure and is composed of a layer of the nitride compound of Ti, Al, and Zr satisfying composition formula: [Ti<SB>1-(E+F)</SB>Al<SB>E</SB>Zr<SB>F</SB>] N (where, E represents 0.45-0.65 and F represents 0.05-0.15 by atomic ratio). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  This invention has excellent heat-resistant plastic deformation properties with a hard coating layer, and also has high-temperature hardness, heat-resistance and high-temperature strength, and therefore high heat of high-hardness steel such as alloy tool steel and hardened material of bearing steel. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that exhibits excellent wear resistance when used in high-speed machining involving generation.

  In general, coated carbide tools include a throw-away tip that is attached to the tip of a cutting tool for turning and planing of various steels and cast irons, and drilling of the work material. There are drills and miniature drills used for processing, etc., 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 work in the same manner as a type end mill is known.

In addition, as a coated carbide tool, a single-phase structure is formed on the surface of a cemented carbide substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. Have and
_{Formula: [Ti 1- (X + Y} ) Al X Zr Y] N ( provided that an atomic ratio, X is 0.45 to 0.65, Y represents a 0.05 to 0.15),
Coated carbide tool formed by vapor-depositing a hard coating layer composed of a composite nitride of Ti, Al, and Zr satisfying the following conditions (hereinafter referred to as (Ti, Al, Zr) N) with an average layer thickness of 2 to 6 μm In such a conventional coated cemented carbide tool, the (Ti, Al, Zr) N layer constituting the hard coating layer has high temperature hardness and heat resistance by the component Al, and high temperature strength by the same Ti. Furthermore, since it has heat-resistant plastic deformation properties due to Zr, it also has excellent resistance when used for cutting hardened steel such as alloy tool steel and hardened material of bearing steel that generate relatively high heat during cutting. It is also known to show wear.

Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, a cathode electrode (evaporation source) in which a Ti—Al—Zr alloy having a composition corresponding to the composition of the (Ti, Al, Zr) N layer that is a hard coating layer is set in a state heated to a temperature of 500 ° C. For example, arc discharge is generated between the anode electrode and the anode electrode under the condition of current: 90 A, and simultaneously, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa, for example. It is also known that it is produced by vapor-depositing a hard coating layer composed of the (Ti, Al, Zr) N layer on the surface of the cemented carbide substrate under the condition that a bias voltage of −100 V is applied.
JP-A-9-104966

  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 the coated carbide tool, when used to perform cutting of high hardness steel such as alloy tool steel and quenching material of bearing steel with relatively high heat generation at the time of cutting under normal cutting conditions, As described above, the cutting edge portion exhibits a normal normal wear form, and there is no problem and exhibits a predetermined wear resistance. In particular, the high-hardness steel is cut at a high speed with higher heat generation. When used under conditions, the hard coating layer (Ti, Al, Zr) N layer undergoes thermoplastic deformation that causes uneven wear, and as a result, the progress of wear is significantly accelerated. To reach the service life in a relatively short time The it is the status quo.

In view of the above, the present inventors have developed the above-mentioned conventional cemented carbide tool exhibiting excellent wear resistance in which the hard coating layer is excellent in high-speed cutting of the above-mentioned high-hardness steel. As a result of conducting research by paying attention to the (Ti, Al, Zr) N layer constituting the hard coating layer of the coated carbide tool,
(A) The (Ti, Al, Zr) N layer constituting the conventional hard coating layer has a high heat resistance plasticity that can sufficiently suppress the thermoplastic deformation during the high-speed cutting of the high hardness steel. If more Zr component is contained for the purpose of securing the deformability, the content ratio of at least one of Ti and Al components as constituent components will decrease, but in this case, if the Ti component decreases If the high-temperature strength and the Al component decrease, it is inevitable that the high-temperature hardness and heat resistance will decrease. Therefore, the content ratio of the Zr component is inevitably about 0.05 to 0.15 atomic%. It must be the content ratio.

(B) Compared to the (Ti, Al, Zr) N layer of (a) above, the Zr content is extremely high, while the content ratio of the Zr component is increased, the Al content is reduced,
_{Formula: [Ti 1- (A + B} ) Al A Zr B] N ( provided that an atomic ratio, A is 0.01 to 0.06, B represents a 0.35 to 0.55) shall satisfy Thus, the low content of Al component makes the high-temperature hardness and heat resistance extremely insufficient, but the high Zr content further improves the heat-resistant plastic deformation (Ti, Al, Zr) N layer (hereinafter referred to as thin layer A) )When,
Compared to the thin layer A, the Al content rate is relatively high, while the Zr content rate is relatively low,
_{Formula: [Ti 1- (C + D} ) Al C Zr D] N ( provided that an atomic ratio, C is 0.20 to 0.35, D denotes the 0.20 to 0.30) shall satisfy Therefore, it has a low Zr content and a relatively low heat-resistant plastic deformability as compared with the thin layer A, but has a high high-temperature hardness and heat resistance due to the relatively high Al content (Ti , Al, Zr) N layer (hereinafter referred to as thin layer B),
Are alternately laminated in a state where each layer has an average layer thickness of 5 to 20 nm (nanometer), and as a result, (Ti, Al, Zr) of the alternately laminated structure of thin layers A and B as a result. In the N layer (in this case, both the thin layer A and the thin layer B contain a Ti component of 35 atomic% or more, thus maintaining high high-temperature strength), excellent heat resistance due to the above-described high Zr-containing thin layer A It should have plastic deformability and high temperature hardness and heat resistance due to the relatively high Al-containing thin layer B.

(C) The (Ti, Al, Zr) N layer having the alternately laminated structure of the thin layer A and the thin layer B of (b) is excellent in heat plastic deformation required for high-speed cutting of high hardness steel. However, since the content ratio of the Al component is relatively low in both the thin layer A and the thin layer B, it does not have sufficiently satisfying high temperature hardness and heat resistance, while the above (a) (Ti, Al, Zr) N layer, ie,
Composition formula: [Ti _{1− (E + F)} Al _E Zr _F ] N (wherein E is 0.45 to 0.65 and F is 0.05 to 0.15 in atomic ratio) The (Ti, Al, Zr) N layer of phase structure does not have sufficient heat-resistant plastic deformation required for high-speed cutting of high-hardness steel, but it has excellent high-temperature hardness due to the high content of Al component. If the hard coating layer is formed as a lower layer of the (Ti, Al, Zr) N layer having the alternate layered structure of the thin layer A and the thin layer B, the resulting hard coating is obtained. Since the layer has excellent heat plastic deformation and high temperature strength, and excellent high temperature hardness and heat resistance, the coated carbide tool formed by vapor-depositing this hard coating layer generates the above high heat generation. Even in high-speed cutting of high hardness steel, the thermoplastic deformation that causes uneven wear Raw without exerting over the superior wear resistance to long term.
The research results shown in (a) to (c) above were obtained.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) Both are composed of an upper layer and a lower layer made of (Ti, Al, Zr) N. The upper layer has an average layer thickness of 0.5 to 1.5 μm, and the lower layer has an average layer thickness of 2 to 6 μm. And
(B) Each of the upper layers has an alternate layered structure of thin layers A and thin layers B each having an average layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
_{Formula: [Ti 1- (A + B} ) Al A Zr B] N ( provided that an atomic ratio, A is 0.01 to 0.06, B represents a from 0.35 to 0.50) satisfies (Ti , Al, Zr) N layer,
The thin layer B is
Composition formula: [Ti _{1− (C + D)} Al _C Zr _D ] N (wherein C is 0.20 to 0.35 and D is 0.20 to 0.30 in terms of atomic ratio) (Ti , Al, Zr) N layer,
(C) the lower layer has a single phase structure;
Composition formula: [Ti _{1− (E + F)} Al _E Zr _F ] N (wherein E is 0.45 to 0.65 and F is 0.05 to 0.15 in atomic ratio) (Ti , Al, Zr) N layer,
It is characterized by a coated carbide tool that exhibits excellent wear resistance in high-speed cutting of high-hardness steel formed by vapor-depositing a hard coating layer made of

Next, the reason why the numerical values of the hard coating layer of the coated carbide tool of the present invention are limited as described above will be described.
(A) Composition formula and average layer thickness of the lower layer As described above, the Al component in the (Ti, Al, Zr) N layer constituting the hard coating layer has high temperature hardness and heat resistance, and the Ti component has high temperature strength. In addition, the Zr component has the effect of improving the heat plastic deformation, and the lower layer maintains a high high-temperature hardness and heat resistance by relatively increasing the Al component content ratio. If the E value indicating the content ratio of Ti is less than 0.45 in terms of the total amount of Ti and Zr (atomic ratio, the same shall apply hereinafter), the desired excellent high-temperature hardness and heat resistance cannot be ensured, The progress of wear is accelerated rapidly. On the other hand, if the E value indicating the Al ratio exceeds 0.65, the high temperature strength decreases rapidly, and as a result, chipping (small chipping) is likely to occur. Therefore, the E value was set to 0.45 to 0.65. .
Further, if the F value indicating the proportion of Zr is a proportion of the total amount of Ti and Al, and less than 0.05, a predetermined heat resistant plastic deformation improvement effect cannot be ensured, while the F value is 0. When it exceeds 15, since a clear decreasing tendency appears in the high-temperature strength, the F value is set to 0.05 to 0.15.
Furthermore, if the average layer thickness is less than 2 μm, the excellent high-temperature hardness and heat resistance cannot be imparted to the hard coating layer over a long period of time, resulting in a short tool life, while the average layer thickness is 6 μm. If it exceeds, chipping is likely to occur, so the average layer thickness was set to 2 to 6 μm.

(B) Composition formula of upper layer thin layer A The Zr component in (Ti, Al, Zr) N of the upper layer thin layer A has a relatively high content ratio as described above, so that the heat resistant plastic deformation is achieved. Has the effect of preventing the occurrence of thermoplastic deformation that causes uneven wear in high-speed cutting of high-hardness steel with high heat generation, but the B value indicating the content ratio is the total amount of Ti and Al. If the ratio is less than 0.35, the desired excellent effect cannot be ensured for the above action. On the other hand, if the B value exceeds 0.55, the high temperature hardness and heat resistance are relatively adjacent to each other. Even if there is an excellent thin layer B, the high-temperature hardness and heat resistance of the upper layer, and further the reduction of the high-temperature strength are unavoidable, and wear is promoted and chipping is likely to occur. Therefore, the B value was determined to be 0.35 to 0.55.
Further, the A value indicating the proportion of Al is the proportion of the total amount of Ti and Zr, and if less than 0.01, the minimum high-temperature hardness and heat resistance cannot be ensured, causing wear promotion, On the other hand, if the A value exceeds 0.06, the high-temperature strength suddenly decreases and causes chipping. Therefore, the A value was set to 0.01 to 0.06.

(C) Composition formula of upper layer thin layer B In the upper layer thin layer B, the content ratio of the Zr component is relatively lower and the content ratio of the Al component is higher than the thin layer A described above. By maintaining it, it has a relatively high high temperature hardness and heat resistance, reinforces the lack of high temperature hardness and heat resistance of the adjacent thin layer A, and thus has excellent heat plastic deformation properties that the thin layer A has. And the upper layer having high temperature hardness and heat resistance is formed by the thin layer B. When the C value indicating the Al content in the composition formula is less than 0.20, the desired high temperature hardness and The heat resistance cannot be ensured and the progress of wear is promoted. On the other hand, if the C value exceeds 0.35, the high temperature strength of the entire upper layer is lowered, which causes chipping. Therefore, the C value was set to 0.20 to 0.35.
Further, if the D value indicating the proportion of Zr is a proportion of the total amount of Ti and Al and is less than 0.20, the heat resistance plastic deformation of the entire upper layer is inevitably lowered, while the D value is 0.30. Since the high-temperature strength suddenly drops when the value exceeds D, the D value is set to 0.20 to 0.30.

(D) Single layer average layer thickness of thin layer A and thin layer B of the upper layer If each layer average layer thickness is less than 5 nm, it is difficult to clearly form each thin layer with the above composition. The desired excellent heat-resistant plastic deformation property and predetermined high-temperature hardness and heat resistance cannot be ensured for the layer, and when the average layer thickness of each layer exceeds 20 nm, the disadvantage of each thin layer, that is, the thin layer If it is A, insufficient high-temperature hardness and heat resistance, and if it is a thin layer B, insufficient heat-resistant plastic deformation will appear locally in the layer, which may cause chipping or promote wear progress. Therefore, the average layer thickness of each layer was determined to be 5 to 20 nm.

(E) Average layer thickness of the upper layer If the average layer thickness is less than 0.5 μm, the excellent heat-resistant plastic deformability cannot be imparted to the hard coating layer over a long period of time, resulting in a short tool life. When the average layer thickness exceeds 1.5 μm, chipping is likely to occur. Therefore, the average layer thickness was set to 0.5 to 1.5 μm.

  In the coated carbide tool of the present invention, the hard coating layer is composed of a (Ti, Al, Zr) N layer, and it is excellent in that the upper layer of the hard coating layer has an alternately laminated structure of the thin layer A and the thin layer B. The alloy tool steel with high heat generation is especially suitable because it has heat plastic deformation, predetermined high temperature hardness and heat resistance, and the lower layer of the single phase structure has excellent high temperature hardness and heat resistance. Even in high-speed cutting of hardened steel such as hardened material for bearing steel, the hard coating layer exhibits excellent heat-resistant plastic deformation, and as a result, there is no occurrence of thermoplastic deformation that causes uneven wear on the cutting edge. The part takes a normal wear form and exhibits excellent wear resistance over a long period of time.

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

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C for 1 hour, after sintering, WC-based carbide with honing of R: 0.03 on the cutting edge and chip shape of ISO standard CNMG120408 Alloy carbide substrates A-1 to A-10 were formed.

In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and 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 pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. The carbide substrates B-1 to B-6 made of TiCN base cermet having the following chip shape were formed.

(A) Next, each of the above carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then the arc ion plate shown in FIG. Attached along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the coating apparatus, and used as a cathode electrode (evaporation source) on one side with the target compositions shown in Tables 3 and 4, respectively. As the upper layer Ti-Al-Zr alloy for forming the thin layer A having the corresponding component composition and the cathode electrode (evaporation source) on the other side, the component compositions corresponding to the target compositions shown in Tables 3 and 4 are also used. A Ti-Al-Zr alloy for forming the thin layer B as an upper layer is disposed opposite to the rotary table, and a cathode is formed along the rotary table at a position shifted by 90 degrees from both the Ti-Al-Zr alloys. Electrode (evaporation source) To likewise respectively mounted Ti-Al-Zr alloy for the lower layer formed having a component composition corresponding to the target composition shown in Tables 3 and 4,
(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 carbide substrate that rotates while rotating on the rotary table is set to −1000 V. And applying a current of 100 A between the lower layer forming Ti—Al—Zr alloy and the anode electrode to generate an arc discharge, whereby the surface of the carbide substrate is made to be the Ti—Al— Bombarded with Zr alloy,
(C) Introducing nitrogen gas as a reaction gas into the apparatus to make a reaction atmosphere of 3 Pa, applying a DC bias voltage of −100 V to a carbide substrate rotating while rotating on the rotary table, and An arc discharge is generated by flowing a current of 100 A between the layer-forming Ti—Al—Zr alloy and the anode electrode, so that the target composition and target layer thickness shown in Tables 3 and 4 are formed on the surface of the cemented carbide substrate. (Ti, Al, Zr) N layer having a single-phase structure is deposited as a lower layer of the hard coating layer,
(D) Next, the flow rate of nitrogen gas as a reaction gas introduced into the apparatus is adjusted to a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to the carbide substrate rotating while rotating on the rotary table. In the applied state, 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-Zr alloy for forming the thin layer A to generate arc discharge, and the carbide A thin layer A having a predetermined layer thickness is formed on the surface of the substrate. After the thin layer A is formed, the arc discharge is stopped, and instead, between the cathode electrode and the anode electrode of the Ti-Al-Zr alloy for forming the thin layer B Similarly, a predetermined current in the range of 50 to 200 A is supplied to generate arc discharge to form a thin layer B having a predetermined thickness, and then the arc discharge is stopped (in this case, starting from the formation of the thin layer B). You may) Formation of thin layer A by arc discharge between cathode electrode and anode electrode of Ti-Al-Zr alloy for forming A, and arc discharge between cathode electrode and anode electrode of Ti-Al-Zr alloy for forming thin layer B The formation of the thin layer B is repeated alternately, so that the thin layer A and the thin layer B having the target composition and the target layer thickness shown in Tables 3 and 4 along the layer thickness direction are alternately formed on the surface of the cemented carbide substrate. The upper layer composed of the laminated layers is vapor-deposited with the overall target layer thickness shown in Tables 3 and 4 as well. 1 to 16 were manufactured.

  For the purpose of comparison, these carbide substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plate shown in FIG. A Ti—Al—Zr alloy having a component composition corresponding to the target composition shown in Table 5 was mounted as a cathode electrode (evaporation source) as a cathode electrode (evaporation source). The apparatus was heated to 500 ° C. with a heater while maintaining a vacuum of 1 Pa or less, and a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and the Ti—Al—Zr alloy and anode of the cathode electrode An electric current of 100 A is passed between the electrodes to generate an arc discharge, whereby the surface of the carbide substrate is bombarded with the Ti—Al—Zr alloy, and then nitrogen gas is introduced into the apparatus as a reactive gas. and a bias voltage applied to the cemented carbide substrate is lowered to −100 V to generate an arc discharge between the cathode electrode and the anode electrode of the Ti—Al—Zr alloy. (Ti, Al, Zr) N layer having a single phase structure with a target composition and a target layer thickness shown in Table 5 on the surface of each of hard substrates A-1 to A-10 and B-1 to B-6 The conventional surface-coated carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 as conventional coated carbide tools were produced by vapor-depositing a hard coating layer made of

Next, the coated carbide tips 1-16 of the present invention and the conventional coated carbide tip 1 in the state where each of the various coated carbide tips is screwed to the tip of the tool steel tool with a fixing jig. About ~ 16
Work material: SKD11 hardened material (hardness: HRC60) round bar,
Cutting speed: 70 m / min. ,
Cutting depth: 0.3 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes
Dry continuous high-speed cutting test (normal cutting speed is 30 m / min.) Of alloy tool steel hardened material under the conditions (cutting condition A)
Work material: JIS / SKD61 hardened material (hardness: HRC52), four longitudinally spaced round bars with equal intervals in the length direction,
Cutting speed: 80 m / min. ,
Cutting depth: 0.5mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed cutting test of alloy tool steel hardened material under the conditions (cutting condition B) (normal cutting speed is 40 m / min.),
Work material: JIS / SUJ2 hardened material (hardness: HRC56) round bar,
Cutting speed: 80 m / min. ,
Cutting depth: 0.4mm,
Feed: 0.15 mm / rev. ,
Cutting time: 8 minutes
The dry continuous high-speed cutting test (normal cutting speed is 40 m / min.) Of the hardened bearing steel under the above conditions (cutting condition C), 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 Three types of sintered carbide rod forming bodies for forming a carbide substrate having diameters of 8 mm, 13 mm, and 26 mm were formed, and further, the three types of round rod sintered bodies described above were subjected to grinding and shown in Table 7. Made of WC-base cemented carbide with a combination of 4 blade square shape with diameter and length of 6mm × 13mm, 10mm × 22mm, and 20mm × 45mm respectively, and a twist angle of 30 degrees. Carbide substrates (end mills) C-1 to C-8 were produced.

  Then, the surfaces of these carbide 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. Under the same conditions as in Example 1, a lower layer composed of a (Ti, Al, Zr) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 8, and also along the layer thickness direction. A coated carbide tool of the present invention is formed by vapor-depositing an upper layer composed of alternating layers of thin layers A and B having a target composition shown in FIG. The present invention surface-coated carbide end mills (hereinafter referred to as the present invention coated carbide end mills) 1 to 8 were produced.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. Then, a hard coating layer composed of a (Ti, Al, Zr) N layer having a single-phase structure having the target composition and target layer thickness shown in Table 9 is deposited under the same conditions as in Example 1. Thus, conventional surface-coated carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated carbide tools were manufactured, respectively.

Next, of the present invention coated carbide end mills 1-8 and conventional coated carbide end mills 1-8, the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm hardened material of JIS SKD61 (hardness: HRC52),
Cutting speed: 100 m / min. ,
Groove depth (cut): 1mm,
Table feed: 150 mm / min,
About the dry high-speed grooving test (normal cutting speed is 50 m / min.) Of the alloy tool steel hardened material under the conditions of the present invention, the coated carbide end mills 4 to 6 and the conventional coated carbide end mills 4 to 6 of the present invention,
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm, JIS / SUJ2 quenching material (hardness: HRC56) plate material,
Cutting speed: 80 m / min. ,
Groove depth (cut): 2 mm,
Table feed: 150 mm / min,
For the dry high-speed grooving test (normal cutting speed is 40 m / min.) Of the hardened bearing steel under the following conditions, the present invention coated carbide end mills 7, 8 and the conventional coated carbide end mills 7, 8:
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm thick JIS / SKD11 quenching material (hardness: HRC60),
Cutting speed: 50 m / min. ,
Groove depth (cut): 4 mm
Table feed: 30 mm / min,
A dry high-speed grooving test (normal cutting speed is 25 m / min.) Of a hardened alloy tool steel under the above conditions was performed. The cutting groove length up to 0.1 mm, which is a guide for the service life, was measured. The measurement results are shown in Tables 8 and 9, respectively.

  The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding), respectively. Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all Carbide substrates (drills) D-1 to D-8 made of a WC-base cemented carbide having a two-blade shape with a twist angle of 30 degrees were produced.

  Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. 1 is also used. A lower layer composed of a (Ti, Al, Zr) N layer having a single-phase structure having a target composition and a target layer thickness shown in Table 10 under the same conditions as in Example 1, and the same layer. By vapor-depositing an 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 along the thickness direction, with the overall target layer thickness also shown in Table 10, The surface coated carbide drills (hereinafter referred to as the present invention coated carbide drills) 1 to 8 as the present invention coated carbide tools were produced, respectively.

  For comparison purposes, the surfaces of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and the arc shown in FIG. A hard material comprising a (Ti, Al, Zr) 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, charged in the ion plating apparatus By depositing a coating layer, conventional surface-coated carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools were manufactured, respectively.

Next, of the present invention coated carbide drills 1-8 and conventional coated carbide drills 1-8, the present invention coated carbide drills 1-3 and conventional coated carbide drills 1-3 are as follows:
Work material—Plate: 100 mm × 250, thickness: 50 mm, JIS / SUJ2 quenching material (hardness: HRC56),
Cutting speed: 40 m / min. ,
Feed: 0.06mm / rev,
Hole depth: 12mm,
With respect to the wet high speed drilling test of the bearing steel hardened material under the conditions (normal cutting speed is 15 m / min.), The present invention coated carbide drills 4-6 and the conventional coated carbide drills 4-6,
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm hardened material of JIS SKD61 (hardness: HRC55),
Cutting speed: 40 m / min. ,
Feed: 0.07mm / rev,
Hole depth: 24mm
Wet high-speed drilling test (normal cutting speed is 15 m / min.) Of the alloy tool steel hardened material under the following conditions, the present invention coated carbide drills 7 and 8 and the conventional coated carbide drills 7 and 8:
Work material—Plate: 100 mm × 250 mm, thickness: 50 mm, JIS / SKD11 quenching material (hardness: HRC58),
Cutting speed: 25 m / min. ,
Feed: 0.05mm / rev,
Hole depth: 40mm,
Wet high-speed drilling machining test (normal cutting speed is 10 m / min.) Of alloy tool steel hardened material under the above conditions, and cutting the tip in any wet high-speed drilling machining test (using water-soluble cutting oil) The number of drilling processes until the flank wear width of the blade surface reached 0.3 mm was measured. The measurement results are shown in Table 8, respectively.

  (Ti, Al, Zr) of the present coated carbide tips 1-16, the present coated carbide end mills 1-8, and the present coated carbide drills 1-8 as the present coated carbide tool obtained as a result. ) Upper thin layer A and thin layer B constituting the hard coating layer made of N, composition of the lower layer, conventional coated carbide tips 1 to 16 as a conventional coated carbide tool, conventional coated carbide end mill 1 to 8 and the composition of the hard coating layer made of (Cr, Al) N of the conventional coated carbide drills 1 to 8 were measured by energy dispersive X-ray analysis using a transmission electron microscope. The composition was substantially the same as the target 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 carbide tools of the present invention has an upper layer in which the hard coating layer has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm. And the thin layer A, the thin layer B, and the lower layer are composed of (Ti, Al, Zr) N having different compositions, and the lower layer is excellent in high-temperature hardness. Heat resistance, and high temperature strength, while the upper layer has excellent heat plastic deformation, predetermined high temperature hardness and heat resistance, and high temperature strength, so that the hard coating layer has these excellent characteristics. Therefore, even in high-speed cutting of high hardness steel such as alloy tool steel and bearing steel quenching material with high heat generation, there is no occurrence of thermoplastic deformation causing uneven wear on the cutting edge, Normal wear form and excellent wear resistance On the other hand, the conventional coated carbide tool in which the hard coating layer is composed of a (Ti, Al, Zr) N layer having a single phase structure is particularly susceptible to thermoplastic deformation in the cutting edge due to the lack of heat-resistant plastic deformation of the hard coating layer. As a result, the wear form becomes an uneven wear form, so that it is clear that the wear progresses faster and reaches the service life in a relatively short time.

  As described above, the coated carbide tool of the present invention is not only for cutting under normal cutting conditions such as various types of steel and cast iron, but particularly for high-hardness steel such as hardened material of alloy tool steel and bearing steel. It exhibits excellent wear resistance even during high-speed cutting with high heat generation, and exhibits excellent cutting performance over a long period of time. It can cope with energy saving and cost reduction sufficiently satisfactorily.

The arc ion plating apparatus used for forming the hard coating layer which comprises this invention coated carbide 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 cemented carbide 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 Zr, the upper layer has an average layer thickness of 0.5 to 1.5 μm, and the lower layer has an average layer thickness of 2 to 6 μm. Have
(B) Each of the upper layers has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
Ti satisfying the composition formula: [Ti _{1− (A + B)} Al _A Zr _B ] N (wherein A is 0.01 to 0.06 and B is 0.35 to 0.55 in atomic ratio) A composite nitride layer of Al and Zr;
The thin layer B is
Ti satisfying the composition formula: [Ti _{1− (C + D)} Al _C Zr _D ] N (wherein C is 0.20 to 0.35 and D is 0.20 to 0.30 in atomic ratio) A composite nitride layer of Al and Zr,
(C) the lower layer has a single phase structure;
Ti satisfying the composition formula: [Ti _{1− (E + F)} Al _E Zr _F ] N (wherein E is 0.45 to 0.65 and F is 0.05 to 0.15 in atomic ratio) A composite nitride layer of Al and Zr;
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance in high-speed cutting of high-hardness steel, formed by vapor-depositing a hard coating layer comprising:

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