JP2007290089A - Surface coated cutting tool having hard coating layer exhibiting excellent chipping resistance in high-speed heavy cutting difficult-to-cut material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cutting tool having a hard coating layer exhibiting excellent chipping resistance in high-speed heavy cutting a difficult-to-cut material. <P>SOLUTION: In this surface coated cutting tool, the following hard coating layer is formed on the surface of a tool base made of WC-base cemented carbide alloy or titanium carbonitride base cermet. The hard coating layer includes: a lower layer; and an upper layer. The lower layer is formed of a composition change (Ti, Al)N layer, wherein it has a component concentration distribution structure in which from the Al highest content point (hereinafter referred to as point A) to the Al lowest content point (hereinafter referred to as point B), and from the point B to the point A, Al and Ti contents respectively continuously change along the direction of layer thickness. The point A satisfies a specific composition formula (Ti<SB>1-X</SB>Al<SB>X</SB>)N, the point B satisfies a specific composition formula (Ti<SB>1-Y</SB>Al<SB>Y</SB>)N, and the interval between the adjacent points A and B is 0.03 to 0.1μm. The upper layer has an alternately stacked structure of a vanadium nitride layer and a vanadium oxide layer respectively having an average layer thickness per layer of 0.4 to 2 μm, in which an acidic nitride vanadium layer is interposed between the respective layers. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  This invention is especially suitable for cutting difficult-to-cut materials such as stainless steel, high manganese steel, and even mild steel under high speed with high heat generation and high cutting depth and high feed that require a high load locally on the cutting edge. The present invention also relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated tool) that exhibits excellent chipping resistance even when performed under high-speed heavy cutting conditions.

  In general, for coated tools, throwaway inserts that are detachably attached to the tip of the cutting tool for turning and planing of various steel and cast iron materials, drilling of the work material, etc. Drills and miniature drills, and solid type end mills used for chamfering, grooving and shouldering 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 coated tool, on the surface of a tool base composed of tungsten carbide (hereinafter referred to as WC) based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) based cermet,
And having an average layer thickness of 1 to 5 μm, and along the layer thickness direction, Al highest content points and Al lowest content points are alternately present at predetermined intervals, and from the Al highest content point Al lowest content point, having a component concentration distribution structure in which the Al and Ti content continuously change from the Al lowest content point to the Al highest content point, respectively,
Furthermore, the Al highest content point is the composition formula: (Ti _1-X Al _X ) N (however, in atomic ratio, X represents 0.70 to 0.95),
The Al minimum content point is a composition formula: (Ti _1-Y Al _Y ) N (however, Y is 0.50 to 0.65 in atomic ratio),
And a composite nitride layer of Ti and Al in which the distance between adjacent Al highest content point and Al minimum content point is 0.03 to 0.1 μm [hereinafter, composition change (Ti, Al) N A coating tool formed by physically vapor-depositing a hard coating layer is known, and the composition change (Ti, Al) N layer, which is the hard coating layer of the coating tool, has a component concentration distribution change structure. Because it has excellent high temperature hardness and heat resistance due to Al and excellent high temperature strength due to the same Ti, when it is used to perform continuous cutting and intermittent cutting of various general steels and ordinary cast iron under normal conditions Needless to say, it is also known that excellent cutting performance is exhibited even when this is used in high-speed cutting conditions.

Further, the above conventional coated tool is, for example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 2A and a schematic front view in FIG. A table is provided, and a Ti-Al alloy having a relatively high Al content (low Ti content) on one side and a relatively high Ti content (on Al content) on the other side, with the rotary table sandwiched therebetween. A low) Ti-Al alloy is used as a cathode electrode (evaporation source) and an arc ion plating apparatus is used, and a plurality of pieces are arranged on the rotary table of the apparatus at positions separated from the central axis in a radial direction by a predetermined distance. The tool base is mounted in a ring shape, and in this state, the atmosphere in the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the tool base is made uniform for the purpose of uniformizing the thickness of the hard coating layer formed by vapor deposition. While rotating itself, arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides to form a composition change (Ti, Al) N layer on the surface of the tool base. In the composition change (Ti, Al) N layer formed as a result, the tool base arranged in a ring shape on the rotary table has a relatively high Al content on the one side. At the point closest to the cathode electrode (evaporation source) of the Ti-Al alloy (low Ti content), the highest Al content point is formed in the layer, and the tool base is relatively Ti-containing on the other side. At the point closest to the cathode electrode of the Ti-Al alloy having a high amount (low Al content), the lowest Al content point is formed in the layer, and the rotation of the rotary table causes the layer to move along the layer thickness direction. Al best The point and the Al lowest content point appear alternately and repeatedly with a predetermined interval, and the Al and Ti contents continuously from the Al highest content point to the Al lowest content point and from the Al lowest content point to the Al highest content point, respectively. A changing component concentration distribution structure is formed.
Japanese Patent No. 3669334

  In recent years, the use of FA for cutting devices has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting processing. As a result, coated tools are affected as much as possible by the grade of work material. There is a tendency not to be versatile, that is, there is a tendency to require a coated tool capable of cutting as many kinds of work materials as possible. However, in the conventional coated tools described above, this is generally applied to low alloy steel, carbon steel, etc. There is no problem when used for high-speed cutting of normal cast iron such as steel, ductile cast iron, gray cast iron, etc. When cutting difficult-to-cut materials such as mild steel at high speeds and high-speed heavy cutting conditions such as high cutting and high feed that apply a high load locally to the cutting edge, it is difficult due to high heat generated during cutting. From the cutting material The work material and its chips are heated to a high temperature and the viscosity is further increased. As a result, the adhesiveness and reactivity to the surface of the hard coating layer are further increased. The occurrence of (slight chipping) increases rapidly, and at the present time, the service life is reached in a relatively short time.

In view of the above, the present inventors have developed the above-mentioned conventional coated tool in order to develop a coated tool that exhibits excellent chipping resistance with a hard coating layer, particularly in high-speed heavy cutting of difficult-to-cut materials. As a result of conducting research with a focus on
(A) A composition change (Ti, Al) N layer, which is a hard coating layer of the above-mentioned conventional coated tool, is formed with an average layer thickness of 1 to 5 μm as a lower layer, and vanadium oxide (vanadium oxide as an upper layer) is formed thereon. Depending on the degree of oxidation, various compound forms such as VO, V ₂ O ₃ and VO ₂ can be taken. Hereinafter, these are collectively referred to as VO). As a result, even when the work material (hard-to-cut material) and its swarf are heated at high temperature due to the heat generated during cutting, the cutting edge (the rake face and flank face and the cutting edge ridge line where these two surfaces intersect) and the workpiece Excellent slipperiness is ensured between the cutting material and the chips, the adhesiveness and reactivity of the work material and the chips to the cutting edge surface are significantly reduced, and the composition change (Ti , Al) Is the N layer well protected? , Compositional changes (Ti, Al) having excellent characteristics N layer may become to be sufficiently exhibited for a long time.

(B) However, when a VO layer is provided directly on the lower layer composed of the composition change (Ti, Al) N layer, the lower composition change (Ti, Al) N layer and the upper layer are formed. Adhesion with the VO layer, which is the upper layer, is not sufficient, and the high temperature strength of the VO layer, which is the upper layer, is not sufficient, resulting in insufficient adhesion between the lower layer and the upper layer of the hard coating layer, and the high temperature strength of the upper layer It is impossible to prevent chipping due to lack.

(C) When the upper layer is configured as an alternate layered structure of VO layers and VN layers, and an upper layer of an alternate layered structure in which a VNO layer is interposed between the VO layer and VN layer, the VN layer is Wear resistance of the VO and VN layers to compensate for the high temperature strength that the VO layer lacks, and the VNO layer enhances film formation reactivity during film formation of the VO layer or VN layer and at the same time promotes grain refinement. In addition, since the VNO layer has excellent adhesion to both the VN layer and the VO layer, the intervening VNO layer also improves the bonding strength between the VO layer and the VN layer. Therefore, the upper layer composed of such an alternately laminated structure has excellent surface slipperiness provided by the VO layer and excellent high temperature strength possessed by the VN layer, and the intervening VNO layer provides the bonding strength and resistance to each layer. wear There will those further improved, as a result, the hard coating layer comprises more more excellent high-temperature strength and excellent surface slipperiness, excellent chipping resistance, it is shown the wear resistance.

(D) The hard coating layer of (c) is an arc ion plating apparatus having a structure shown in, for example, a schematic plan view in FIG. 1 (a) and a schematic front view in FIG. A substrate mounting turntable is provided, a cathode electrode (evaporation source) is provided across the turntable, and a metal V is disposed on one of them as a cathode electrode (evaporation source), along the turntable, and Ti-Al alloy having a relatively high Al content (low Ti content) as a cathode electrode (evaporation source) on one side at a position 90 degrees away from each of the metals V, and a relatively Ti content on the other side Using a vapor deposition apparatus in which a high amount (low Al content) Ti—Al alloy is disposed as a cathode electrode (evaporation source) and is disposed at a position spaced apart from the central axis on the rotary table by a predetermined distance in the radial direction. Outside A plurality of tool bases are mounted in a ring shape along the section, and in this state, the rotary table is rotated with the atmosphere inside the apparatus as a nitrogen atmosphere, and the tool is formed for the purpose of uniformizing the thickness of the hard coating layer formed by vapor deposition While rotating the base itself, basically, first, arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of both Ti-Al alloys arranged opposite to each other, and the lower part is formed on the surface of the tool base. As a layer, a composition change (Ti, Al) N layer is deposited with an average layer thickness of 1 to 5 μm,
Next, the arc discharge between the cathode electrode (evaporation source) and the anode electrode of both the Ti—Al alloys is stopped, and the metal that is the cathode electrode (evaporation source) is kept in the same nitrogen atmosphere. An arc discharge is generated between V and the anode electrode, and a VN layer is deposited with an average layer thickness of 0.4 to 2 μm, and then the arc discharge between the metal V and the anode electrode is stopped, Stop supplying nitrogen gas into the device, evacuate the device for about 10 seconds,
Thereafter, the supply of a mixed gas of oxygen gas and nitrogen gas into the apparatus (however, the volume composition ratio of O ₂ : N ₂ = 1: 2) is started, and the atmosphere in the vapor deposition apparatus is changed to an oxygen-nitrogen mixed gas of 1.5 Pa. While maintaining the atmosphere, a current of 120 A was passed between the metal V, which is the cathode electrode (evaporation source), and the anode electrode to generate arc discharge to form a 0.02-0.2 μm VNO layer. Thereafter, the arc discharge between the metal V and the anode electrode is stopped, and at the same time, the supply of the oxygen-nitrogen mixed gas into the apparatus is stopped, and the inside of the apparatus is evacuated for about 10 seconds,
Thereafter, supply of oxygen gas into the apparatus is started to switch the atmosphere in the apparatus to an oxygen atmosphere, and then arc discharge is again generated between the metal V as the cathode electrode (evaporation source) and the anode electrode, After depositing a VO layer with an average thickness of 0.4-2 μm on the VNO layer, the arc discharge between the metal V and the anode electrode is stopped, and the supply of oxygen gas into the apparatus is stopped. After evacuating the device for about 10 seconds,
Supply of oxygen-nitrogen mixed gas (capacitance composition ratio of O ₂ : N ₂ = 1: 2) into the apparatus was started and the atmosphere in the vapor deposition apparatus was maintained in an oxygen-nitrogen mixed gas atmosphere of 1.5 Pa. Then, a current of 120 A is passed between the metal V as the cathode electrode (evaporation source) and the anode electrode to generate arc discharge to form a 0.02-0.2 μm VNO layer, and then the metal V The arc discharge between the anode electrode and the anode electrode is stopped, at the same time, the supply of the oxygen-nitrogen mixed gas into the apparatus is stopped, the inside of the apparatus is evacuated for about 10 seconds,
Thereafter, supply of nitrogen gas into the apparatus is started to switch the atmosphere to a nitrogen atmosphere, and arc discharge is generated again between the metal V, which is the cathode electrode (evaporation source), and the anode electrode, and is superimposed on the VNO layer. VN layer is vapor-deposited with an average layer thickness of 0.4-2 μm,
Thereafter, the VNO layer, the VO layer, and the VN layer are vapor-deposited by repeating the same procedure as described above, thereby forming an alternately laminated structure of the VN layer and the VO layer, and between the VN layer and the VO layer. An upper layer having a target total layer thickness (1 to 5 μm) having a laminated structure with a VNO layer interposed can be formed by vapor deposition.

(E) A coated tool formed by vapor-depositing a hard coating layer composed of the lower layer and the upper layer of a laminated structure is particularly difficult to cut stainless steel, high manganese steel, and mild steel with high viscosity and adhesion. Even if the cutting of the material is performed under high-speed heavy cutting conditions such as high cutting with high heat generation and high cutting with high load and high feed, the composition change (Ti, Al) N layer as the lower layer It has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength, and the upper layer composed of the laminated structure has excellent surface slipperiness possessed by the VO layer and high-temperature strength possessed by the VN layer, and VNO By interposing the layers, the wear resistance of the VO layer and the VN layer is improved, and the bonding strength between the layers is also improved. As a result, not only the entire upper layer has excellent surface slipperiness, but also excellent high temperature strength and resistance. Combined with wear The hard coating layer having such a structure as a whole has excellent surface slipperiness, excellent high-temperature strength, wear resistance, and between the difficult-to-cut material and the chips. Since the excellent surface slipperiness is ensured and the high-speed heavy cutting processing is performed with the stickiness and reactivity of the difficult-to-cut materials and chips to the cutting edge surface being significantly reduced, The occurrence of chipping in the parts is eliminated, and excellent wear resistance is exhibited over a long period of time.
The research results shown in (a) to (e) above were obtained.

This invention was made based on the above research results, and on the surface of the tool base,
(A) It has an average layer thickness of 1 to 5 μm, and along the layer thickness direction, Al maximum content points and Al minimum content points are alternately present at predetermined intervals, and the Al maximum content A component concentration distribution structure in which the Al and Ti contents continuously change from the point to the Al minimum content point, from the Al minimum content point to the Al maximum content point,
Furthermore, the Al highest content point is the composition formula: (Ti _1-X Al _X ) N (however, in atomic ratio, X represents 0.70 to 0.95),
The Al minimum content point is a composition formula: (Ti _1-Y Al _Y ) N (however, Y is 0.50 to 0.65 in atomic ratio),
A lower layer composed of a composition change (Ti, Al) N layer in which the interval between the Al highest content point and the Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
(B) a vanadium nitride layer having a single layer average layer thickness of 0.4 to 2 μm and a vanadium oxide layer having a single layer average layer thickness of 0.4 to 2 μm, and a vanadium nitride layer and a vanadium oxide layer; An upper layer having an overall average layer thickness of 1 to 5 μm, with a vanadium oxynitride layer having an average layer thickness of 0.02 to 0.2 μm interposed between each of the layers,
It is characterized by a coated tool that exhibits excellent chipping resistance in high-speed heavy cutting of difficult-to-cut materials, which is formed by forming a hard coating layer composed of (a) and (b) above. is there.

Next, regarding the constituent layers of the hard coating layer of the coated tool of the present invention, the reason why the numerical values are limited as described above will be described.
(A) Lower layer (a) Composition of Al highest content point Al in the composition change (Ti, Al) N layer improves the high temperature hardness and heat resistance, while the same Ti is included for the purpose of improving the high temperature strength. Therefore, if the Al ratio (X value) at the highest Al content point exceeds 0.95 in terms of the total amount with Ti (atomic ratio), the Ti ratio becomes too low and abruptly increases. High-temperature strength decreases and chipping (minute chipping) is likely to occur on the cutting edge. On the other hand, if the ratio (X value) is also less than 0.70, the ratio of Al becomes too low, and the desired excellent Therefore, the ratio was determined to be 0.70 to 0.95.

(B) Composition of Al minimum content point As described above, the Al maximum content point is excellent in high-temperature hardness and heat resistance, but on the other hand, it is inferior in high-temperature strength. In order to compensate for this, the content of Ti is relatively high, and thereby the Al minimum content point that has a high high-temperature strength is alternately interposed in the thickness direction. Therefore, the Al content (Y value) is If the ratio (atomic ratio) in the total amount with Ti exceeds 0.65, the desired excellent high-temperature strength cannot be secured, while if the ratio (Y value) is also less than 0.50, the relative In particular, the ratio of Ti is excessively increased, and the minimum Al content point cannot be provided with the desired high-temperature hardness and heat resistance. Therefore, the ratio is set to 0.50 to 0.65.

(C) Interval between the highest Al content point and the lowest Al content point If the distance is less than 0.03 μm, it is difficult to clearly form each point with the above composition. As a result, each layer has a desired high temperature. When it becomes impossible to secure the characteristics and high temperature strength and the interval exceeds 0.1 μm, the disadvantages of each point, that is, when the Al highest content point is insufficient high temperature strength, when the Al minimum content point is high temperature characteristics The shortage appears locally in the layer, which makes it easier for chipping to occur on the cutting edge and promotes the progress of wear. Therefore, the interval was set to 0.03 to 0.1 μm.

(D) Average layer thickness If the average layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 5 μm, chipping tends to occur on the cutting edge. The average layer thickness was determined to be 1 to 5 μm.

(B) Upper layer (a) Single layer average layer thickness of vanadium nitride layer (VN layer) constituting alternate layered structure of upper layer VN layer constituting alternate layered structure of upper layer of hard coating layer itself was excellent It has high-temperature strength and compensates for the lack of high-temperature strength of the VO layer. However, if the average layer thickness of the VN layer is less than 0.4 μm, the improvement of the high-temperature strength of the upper layer is not sufficient, while the average layer thickness is 2 μm. If exceeded, the lubricating properties (surface slipperiness) required for the upper layer of the hard coating layer in heavy cutting of difficult-to-cut materials cannot be fully exhibited, and the high temperature hardness of the hard coating layer also decreases. Since this causes a decrease in wear resistance, the average layer thickness was determined to be 0.4 to 2 μm.

(B) Single layer average layer thickness of the vanadium oxide layer (VO layer) constituting the alternate layer structure of the upper layer The VO layer constituting the alternate layer structure of the upper layer of the hard coating layer has excellent surface slipperiness, The adhesion and reactivity to the work material (difficult-to-cut material) and swarf are extremely low, and this is the lower layer because the work material is maintained without change even when the work material is heated at the time of cutting. Protects the Ti, Al) N layer from the work material and chips heated at high temperature and suppresses the occurrence of chipping. However, if the average layer thickness is less than 0.4 μm, the above action is desirable. On the other hand, if the average layer thickness exceeds 2 μm, the chipping tends to occur even if the high temperature strength is reinforced by the alternately laminated structure with the VN layer. Is set to 0.4-2 μm I tried.

(C) Single layer average layer thickness of vanadium oxynitride layer (VNO layer) constituting the laminated structure of the upper layer The VNO layer is formed by forming a VO layer or a VN layer on the VNO layer. It enhances film formation reactivity and promotes crystal grain refinement during film formation, thus improving the wear resistance of the VO layer or VN layer. In addition, both the VN layer and the VO layer are effective. Since it has excellent adhesion, by interposing the VNO layer between the VN layer and the VO layer, the adhesion / bonding strength between the layers of the upper layer of the laminated structure is improved. As a result, the upper layer as a whole is improved. Although it contributes to the improvement of high temperature strength and wear resistance, if the average layer thickness of the VNO layer is less than 0.02 μm, the effect of improving the bonding strength and wear resistance is not sufficient, while the average layer thickness is 0 Hard coating when exceeding 2μm Since the can not be sufficiently exhibited surface slip properties required for the upper layer, it was determined and the average layer thickness and 0.02～0.2Myuemu.

(D) Overall average layer thickness of the upper layer If the overall average layer thickness of the upper layer is less than 1 μm, the high-speed heavy cutting of difficult-to-cut materials cannot sufficiently exhibit the excellent surface slipperiness, It cannot be expected to reduce the adhesion and reactivity of the work material (difficult-to-cut material) and cutting chips to the surface of the cutting edge. On the other hand, if the overall average layer thickness exceeds 5 μm, the hard coating layer is hardened at high temperature. Therefore, the overall average layer thickness was determined to be 1 to 5 μm.

  In the coated tool of the present invention, the composition change (Ti, Al) N layer of the lower layer constituting the hard coating layer has excellent high-temperature hardness and heat resistance, excellent high-temperature strength, and intervenes a VNO layer. Since the upper layer composed of the alternating laminated structure has excellent surface slipperiness, high temperature strength, and wear resistance as a whole upper layer, the hard coating layer as a whole has excellent high temperature hardness, heat resistance, High temperature strength, wear resistance and surface slipperiness, resulting in high heat generation, especially with high heat generation of difficult-to-cut materials such as highly viscous and sticky stainless steel, high manganese steel, and mild steel Even with heavy cutting, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of time.

  Next, the coated 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 in 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 tool bases A-1 to A-10 were formed.

In addition, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, mix these raw material powders into the composition shown in Table 2, wet mix for 24 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / Tool bases B-1 to B-6 made of TiCN base cermet having a chip shape of CNMG120408 were formed.

(A) Next, each of the tool bases A-1 to A-10 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, and then the arc ion plating shown in FIG. Attached along the outer periphery at a position that is a predetermined distance in the radial direction from the central axis on the rotary table in the apparatus, a cathode electrode (evaporation source) is provided across the rotary table, and one of the cathode electrodes (evaporation source) The metal V is arranged as a source), and the Al content is relatively high as a cathode electrode (evaporation source) on one side of the position along the rotary table and 90 degrees away from each of the metals V ( Ti-Al alloy (low Ti content), Ti-Al alloy having a relatively high Ti content (low Al content) on the other side as a cathode electrode (evaporation source), facing each other,
(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. A DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between one of the two Ti-Al alloys for forming the lower layer of the cathode electrode and the anode electrode. The surface is bombarded with the Ti-Al alloy,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, and a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table. A current of 100 A is passed between the cathode electrode (the Ti-Al alloy for forming the highest Al content point and the Ti-Al alloy for forming the lowest Al content point) and the anode electrode to generate an arc discharge, whereby the tool base The Al maximum content point and the Al minimum content point of the target composition shown in Tables 3 and 4 are alternately present at the target intervals shown in Tables 3 and 4 alternately along the layer thickness direction, and It has a component concentration distribution structure in which the Al (Ti) content continuously changes from the highest Al content point to the lowest Al content point, from the lowest Al content point to the highest Al content point, and , Compositional change with target layer thicknesses shown in 4 (Ti, Al) N layer was vapor deposited as the lower layer of the hard coating layer,
(D) The arc discharge between the cathode electrode and the anode electrode of both the Ti-Al alloys for forming the lower layer is stopped, the atmosphere in the apparatus is maintained in a nitrogen atmosphere of 4 Pa, and the direct current to the tool substrate is maintained. Under the condition that the bias voltage is also -100 V, a current of 120 A is caused to flow between the metal V of the cathode electrode and the anode electrode to generate an arc discharge. After the deposition of the layer, the arc discharge between the metal V and the anode electrode is stopped, at the same time, the supply of nitrogen gas into the apparatus is stopped, and the apparatus is evacuated for about 10 seconds,
(E) Thereafter, supply of a mixed gas of oxygen gas and nitrogen gas (however, a volume composition ratio of O ₂ : N ₂ = 1: 2) into the apparatus was started, and the atmosphere in the vapor deposition apparatus was changed to 1.5 Pa of oxygen − While maintaining the nitrogen mixed gas atmosphere, a current of 120 A is passed between the cathode V (evaporation source) metal V and the anode electrode to generate arc discharge, and thus the single layer shown in Tables 3 and 4 After the VNO layer having the target layer thickness is formed by vapor deposition, the arc discharge between the metal V and the anode electrode is stopped. At the same time, the supply of the oxygen-nitrogen mixed gas is stopped into the apparatus, and the apparatus is evacuated for about 10 seconds. Pull,
(F) Thereafter, supply of oxygen gas into the apparatus is started to switch the atmosphere in the vapor deposition apparatus to an oxygen atmosphere of 0.2 Pa, and again 120 A between the metal V as the cathode electrode (evaporation source) and the anode electrode. Then, an arc discharge is generated by depositing a VO layer having a target layer thickness shown in Tables 3 and 4 on the VNO layer, and then an arc between the metal V and the anode electrode is formed. The discharge is stopped, the supply of oxygen gas into the apparatus is stopped, the inside of the apparatus is evacuated for about 10 seconds (g), and then the oxygen-nitrogen mixed gas (O ₂ : N ₂ = 1: 2 capacity) is entered into the apparatus. (Composition ratio) was started, and the atmosphere in the vapor deposition apparatus was maintained in a 1.5 Pa oxygen-nitrogen mixed gas atmosphere, while 120 A of the cathode V (evaporation source) was placed between the metal V and the anode electrode. An electric current is passed to generate an arc discharge, Thus, after the VNO layer having the target layer thickness shown in Tables 3 and 4 is formed by vapor deposition, the arc discharge between the metal V and the anode electrode is stopped, and at the same time, the oxygen-nitrogen mixed gas is supplied into the apparatus. Stop and evacuate the device for about 10 seconds,
(H) Thereafter, supply of nitrogen gas into the apparatus is started, and the atmosphere in the vapor deposition apparatus is kept at a nitrogen atmosphere of 2 Pa, and 120 A is provided between the metal V as the cathode electrode (evaporation source) and the anode electrode. Then, arc discharge is caused to flow, and after VN layer having a target layer thickness shown in Tables 3 and 4 is formed by vapor deposition, arc discharge between the metal V and the anode electrode is stopped, At the same time, the supply of nitrogen gas into the apparatus is stopped, the inside of the apparatus is evacuated for about 10 seconds,
(J) The above steps (e) to (h) are repeated, and an upper layer having a target total layer thickness consisting of an alternately laminated structure of VN layers and VO layers through VNO layers as shown in Tables 3 and 4 is formed by vapor deposition. To do.
Hard coating layers were formed by vapor deposition according to the above (a) to (j), and surface coating throwaway tips (hereinafter referred to as the present invention coated tips) 1 to 16 as the present invention coated tools were produced, respectively.

For comparison purposes,
(A) Each of the above-mentioned tool bases A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, and on the rotating table in the arc ion plating apparatus shown in FIG. Therefore, as the cathode electrode (evaporation source) on one side, the Ti-Al alloy for forming the lowest Al content point with various component compositions, and the various component compositions as the cathode electrode (evaporation source) on the other side The Ti-Al alloy for forming the highest Al content point was placed oppositely across the rotary table,
(B) First, the inside of the apparatus was heated to 500 ° C. with a heater while the inside of the apparatus was evacuated and maintained at a vacuum of 0.1 Pa or less, and then a −1000 V DC bias voltage was applied to the tool base, and the cathode An arc discharge is generated by passing a current of 100 A between either one of the two Ti—Al alloys of the electrode and the anode electrode, and the tool substrate surface is bombarded with the Ti—Al alloy,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, and a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table. A current of 100 A is passed between the cathode electrode (the Ti-Al alloy for forming the lowest Al content point and the Ti-Al alloy for forming the highest Al content point) and the anode electrode to generate an arc discharge, and thereby the tool base The Al minimum content point and the Al maximum content point of the target composition shown in Tables 5 and 6 are alternately present at the target intervals shown in Tables 5 and 6 alternately along the layer thickness direction, and It has a component concentration distribution structure in which the Al (Ti) content continuously changes from the highest Al content point to the lowest Al content point, from the lowest Al content point to the highest Al content point, and 6, a composition change (Ti, Al) N layer corresponding to the lower layer of the above-described coated chip of the present invention having a target layer thickness shown in FIG. 1 to 16 (hereinafter referred to as conventional coated chips) were produced.

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 16 and the conventional coated chips 1 to 16 are as follows.
Work material: JIS · SCMnH1 lengthwise equidistant four round grooved round bars,
Cutting speed: 300 m / min. ,
Cutting depth: 3.5 mm,
Feed: 0.25 mm / rev. ,
Cutting time: 5 minutes,
In the above conditions (cutting condition A), a dry-intermittent and high-cutting cutting test of high manganese steel (normal cutting speed and cutting amount are 200 m / min. And 1.5 mm, respectively),
Work material: JIS / SUS316 round bar,
Cutting speed: 320 m / min. ,
Cutting depth: 4 mm,
Feed: 0.25 mm / rev. ,
Cutting time: 10 minutes,
(Continuous cutting speed and cutting amount are 220 m / min. And 1.5 mm, respectively) of stainless steel under the above conditions (cutting condition B),
Work material: JIS / S15C round bar,
Cutting speed: 280 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.4 mm / rev. ,
Cutting time: 5 minutes,
(Continuous cutting speed and feed are 180 m / min. And 0.25 mm / rev., Respectively) The flank wear width of the cutting edge was measured. The measurement results are shown in Table 7.

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 μm Co powder, mix these raw material powders with the composition shown in Table 8, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and 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 Then, three types of round rod sintered bodies for forming a tool base having diameters of 8 mm, 13 mm, and 26 mm are formed, and further, the three types of round bar sintered bodies are ground and are 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. Tool bases (end mills) C-1 to C-8 were produced.

  Subsequently, the surfaces of these tool bases (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, the Al lowest content point and the Al highest content point of the target composition shown in Table 9 along the layer thickness direction are alternately repeated at the target interval shown in Table 9, and It has a component concentration distribution structure in which the Al (Ti) content continuously changes from the highest Al content point to the lowest Al content point, from the lowest Al content point to the highest Al content point, and is also shown in Table 9 Composition of target layer thickness (Ti, Al) It is composed of a lower layer composed of an N layer and an alternate laminated structure of a VN layer, a VNO layer and a VO layer having a target layer thickness as shown in Table 9 (target entire layer) Composed of upper layer (thick) By depositing form the quality coating layer, the present invention surface-coated cemented carbide end mills of the present invention coated tool (hereinafter, the present invention refers to the coating end mill) 1-8 were prepared, respectively.

  For the purpose of comparison, the surfaces of the tool bases (end mills) C-1 to C-8 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 lowest Al content point and the highest Al content point of the target composition shown in Table 10 along the layer thickness direction are alternately repeated at the target interval shown in Table 10 as well. And having a component concentration distribution structure in which the Al (Ti) content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and The conventional surface-coated carbide as a conventional coating tool is formed by depositing a composition change (Ti, Al) N layer corresponding to the lower layer of the above-described coated end mill of the present invention with the target layer thickness shown in Table 10 as a hard coating layer. Endomi (Hereinafter, conventional coating end mill called) was 1-8 were prepared, respectively.

Next, of the present invention coated end mills 1-8 and the conventional coated end mills 1-8,
About this invention coated end mills 1-3 and conventional coated end mills 1-3,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 100 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 200 mm / min,
High-manganese steel dry high-grooving groove cutting test under normal conditions (normal cutting speed and groove depth are 60 m / min. And 3 mm, respectively),
About this invention coated end mills 4-6 and conventional coated end mills 4-6,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 120 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 250 mm / min,
Stainless steel dry-type high feed groove cutting test under normal conditions (normal cutting speed and table feed are 70 m / min. And 130 mm / min, respectively)
For the coated end mills 7 and 8 of the present invention and the conventional coated end mills 7 and 8,
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 90 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 200 mm / min,
A dry high-groove grooving test of mild steel under the conditions (normal cutting speed and groove depth are 50 m / min. And 10 mm, respectively). The cutting groove length was measured until the flank wear width reached 0.1 mm, which is a guide for the service life. The measurement results are shown in Tables 9 and 10, respectively.

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

  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. In the same conditions as in Example 1 above, the target minimum distance between the Al minimum content point and the Al maximum content point of the target composition shown in Table 11 along the layer thickness direction is also shown in Table 11 alternately. And a component concentration distribution structure in which the Al (Ti) content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, In addition, a lower layer composed of a composition change (Ti, Al) N layer of the target layer thickness shown in Table 11 and a VN layer and a VO layer through the VNO layer of the single target layer thickness also shown in Table 11 Consists of alternating layered structure ( By vapor-depositing a hard coating layer composed of an upper layer (of the total thickness of the standard), the surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 8 as the present invention-coated tools are formed. Each was manufactured.

  For the purpose of comparison, the surface of the tool base (drill) D-1 to D-8 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 Al minimum content point and the Al maximum content point of the target composition shown in Table 12 along the layer thickness direction are also shown in Table 12 alternately. And a component concentration distribution structure in which the Al (Ti) content continuously changes from the highest Al content point to the lowest Al content point and from the lowest Al content point to the highest Al content point. And forming a composition change (Ti, Al) N layer corresponding to the lower layer of the above-described coated drill of the present invention having the target layer thickness shown in Table 12 as a hard coating layer. Conventional surface coating Cemented carbide drills (hereinafter, conventional coating drill called) was 1-8 were prepared, respectively.

Next, among the above-mentioned present invention coated drills 1-8 and conventional coated drills 1-8,
About this invention coated drill 1-3 and conventional coated drill 1-3,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 110 m / min. ,
Feed: 0.40 mm / rev,
Hole depth: 8 mm,
Wet high speed drilling test of high manganese steel under the following conditions (normal cutting speed and feed are 60 m / min. And 0.2 mm / rev, respectively)
About this invention coated drill 4-6 and conventional coated drills 4-6,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 160 m / min. ,
Feed: 0.4 mm / rev,
Hole depth: 20 mm,
Wet high-speed drilling test of stainless steel under the following conditions (normal cutting speed and feed are 90 m / min. And 0.25 mm / rev, respectively)
About this invention covering drills 7 and 8 and conventional covering drills 7 and 8,
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 180 m / min. ,
Feed: 0.50 mm / rev,
Hole depth: 28 mm,
Wet high-speed drilling test of mild steel under the following conditions (normal cutting speed and feed are 120 m / min. And 0.25 mm / rev, respectively)
In each wet high-speed drilling test (using water-soluble cutting oil), the number of drilling processes until the flank wear width of the tip cutting edge surface reached 0.3 mm was measured. The measurement results are shown in Tables 11 and 12, respectively.

The composition change (Ti, Al) N constituting the hard coating layers 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 tools obtained as a result. Layer (lower layer), and conventional coated chips 1 to 16 as a conventional coated carbide tool, conventional coated end mills 1 to 8, and a hard coating layer of conventional coated drills 1 to 8 (Ti, Al) N layer The composition of the Al minimum content point and the Al maximum content point was measured by energy dispersive X-ray analysis using a transmission electron microscope. It showed the same composition.
Furthermore, when the composition of the vanadium nitride layer, vanadium oxynitride layer, and vanadium oxide layer constituting the upper layer of the hard coating layer of the coated tool of the present invention was measured by energy dispersive X-ray analysis using a transmission electron microscope, The vanadium nitride layer is composed mainly of VN, the vanadium oxynitride layer is composed mainly of VNO, and the vanadium oxide layer is composed mainly of VO, which contains V ₂ O ₃ and VO _2. Showed the organization.

  In addition, the average layer thickness of the lower layer of the hard coating layer, the average layer thickness of the vanadium nitride layer, vanadium oxynitride layer and vanadium oxide layer constituting the upper layer of the alternately laminated structure, and the total thickness of the upper layer are scanned. When a cross-section was measured using a scanning electron microscope, all showed an average value (average value of five locations) substantially the same as the target layer thickness.

  From the results shown in Tables 3 to 7 and 9 to 12, the coated tools of the present invention are all high speed conditions accompanied by high heat generation of difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel, which are particularly highly viscous and sticky. The composition change (Ti, Al) N layer, which is the lower layer of the hard coating layer, has excellent high-temperature hardness and heat resistance, even under high-speed heavy cutting under heavy cutting conditions such as high cutting and high feed. Further, excellent surface slippage between the work material and the chips is achieved by an upper layer having an excellent laminated structure of vanadium nitride and vanadium oxide layers having a high temperature strength and interposing a vanadium oxynitride layer. As a result, the high temperature strength and wear resistance of the upper layer as a whole are maintained, so that excellent wear resistance is exhibited over a long period of time without occurrence of chipping. On the other hand, in the conventional coated tool in which the hard coating layer is composed of a composition change (Ti, Al) N layer, the high-speed heavy cutting of the difficult-to-cut material is accompanied by high heat generation, so that The stickiness and reactivity between the material (difficult-to-cut materials) and the chips and the hard coating layer is further increased, and this causes chipping at the cutting edge, resulting in a relatively short service life. It is clear that

  As described above, the coated tool of the present invention is not only for cutting of general steel and ordinary cast iron, but also has high heat generation, and the high-speed heavy load of difficult-to-cut materials in which a high load is locally applied to the cutting edge. Even when used for cutting, it exhibits excellent chipping resistance and exhibits excellent cutting performance over a long period of time. It can cope with low cost sufficiently satisfactorily.

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

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) It has an average layer thickness of 1 to 5 μm, and along the layer thickness direction, Al maximum content points and Al minimum content points are alternately present at predetermined intervals, and the Al maximum content A component concentration distribution structure in which the Al and Ti contents continuously change from the point to the Al minimum content point, from the Al minimum content point to the Al maximum content point,
Furthermore, the Al highest content point is the composition formula: (Ti _1-X Al _X ) N (however, in atomic ratio, X represents 0.70 to 0.95),
The Al minimum content point is a composition formula: (Ti _1-Y Al _Y ) N (however, Y is 0.50 to 0.65 in atomic ratio),
And a lower layer composed of a composite nitride layer of Ti and Al in which the interval between the Al highest content point and the Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
(B) a vanadium nitride layer having a single layer average layer thickness of 0.4 to 2 μm and a vanadium oxide layer having a single layer average layer thickness of 0.4 to 2 μm, and a vanadium nitride layer and a vanadium oxide layer; An upper layer having an overall average layer thickness of 1 to 5 μm, with a vanadium oxynitride layer having an average layer thickness of 0.02 to 0.2 μm interposed between each of the layers,
A surface-coated cutting tool that exhibits a chipping resistance with excellent hard coating layer in high-speed heavy cutting of difficult-to-cut materials, formed by forming the hard coating layer composed of (a) and (b) above.

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