JP2007290083A - 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 including (a) and (b) is formed on the surface of a tool base made of tungsten carbide-base cemented carbide alloy or titanium carbonitride base cermet. The hard coating layer includes: (a) a lower layer; and (b) an upper layer. The lower layer (a) is formed of a composite nitride layer of Cr, Al, and V, which has an average layer thickness of 1 to 5μm, and satisfies a composition formula (Cr<SB>1-X-Y</SB>Al<SB>X</SB>V<SB>Y</SB>)N (wherein by the atomic ratio, X is 0.30 to 0.60, and Y is 0.05 to 0.30). The upper layer (b) 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 having an average layer thickness per layer of 0.02 to 0.2 μm is interposed between the respective layers, and has the total average layer thickness of 1 to 5 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  This invention exhibits excellent chipping resistance with a hard coating layer, especially when cutting difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel under heavy cutting conditions such as high cutting and high feed. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool).

  In general, for coated tools, throwaway inserts that 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,
Composition formula: (Cr _1-XY Al _X V _Y ) N (however, in atomic ratio, X represents 0.30 to 0.60, Y represents 0.05 to 0.30),
There is known a coated tool formed by physically vapor-depositing a hard coating layer composed of a composite nitride of Cr, Al, and V (hereinafter referred to as (Cr, Al, V) N) satisfying the following conditions with an average thickness of 1 to 15 μm. The (Cr, Al, V) N layer, which is a hard coating layer of the above-mentioned coated tool, was excellent in high-temperature hardness and heat resistance by Al as a constituent component, high-temperature strength by Cr, and further by containing V. It is also known that when it is used for continuous cutting and intermittent cutting of various general steels and ordinary cast iron, it exhibits excellent cutting performance since it has lubrication characteristics (surface slipperiness).

Further, the above-mentioned coated tool, for example, the above-mentioned tool base is loaded into an arc ion plating apparatus which is a kind of physical vapor deposition apparatus shown schematically in FIG. An arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Cr—Al—V alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of Nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the above-described (Cr, It is also known to be produced by vapor-depositing a hard coating layer consisting of an Al, V) N layer.
JP 2003-34859 A

  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, energy saving, and cost reduction for cutting processing. As a result, cutting tools are affected as much as possible by the material type of the work material. There is a tendency to demand a cutting tool that can cut as many grades as possible, but in the above-mentioned conventional coated tools, this is applied to general steel such as low alloy steel and carbon steel, and ductile There is no problem when it is used for cutting of ordinary cast iron such as cast iron and gray cast iron, but it is difficult to cut stainless steel, high manganese steel, and mild steel, etc., which have high chip viscosity and are easy to weld to the tool surface. If cutting of the material (work material) is performed under heavy cutting conditions such as high cutting and high feed that locally apply a high load to the cutting edge, the work material and chips are generated by the heat generated during cutting. Is heated to high temperature As a result, the viscosity increases further, and the adhesiveness and reactivity to the hard coating layer surface further increase. As a result, the occurrence of chipping (slight chipping) at the cutting edge increases rapidly, which is the cause of this. At present, the service life is reached in a relatively short time.

Therefore, the present inventors, from the above viewpoint, especially when cutting difficult-to-cut materials such as stainless steel, high manganese steel and mild steel under heavy cutting conditions such as high cutting and high feed, As a result of conducting research while focusing on the above conventional coated tools in order to develop a coated tool that exhibits excellent chipping resistance with a hard coating layer,
(A) The (Cr, Al, V) N layer, which is a hard coating layer of the above conventional coated carbide tool, is formed with an average layer thickness of 1 to 5 μm as a lower layer, and vanadium oxide (oxide) as an upper layer thereon Vanadium can take various compound forms such as VO, V ₂ O ₃ and VO ₂ depending on the degree of oxidation, but when these are collectively referred to as VO), the VO layer is surface slippery. 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 and flank surfaces, and the cutting edge ridge line where these two surfaces intersect) And the work material and the chips are further improved in slipperiness, the adhesiveness and reactivity of the work material and the chips to the cutting edge surface are remarkably reduced, and the lower layer. (Cr, Al, V) N layer is well protected To become so.

(B) However, when the VO layer is provided directly on the lower layer made of the (Cr, Al, V) N layer, the lower layer (Cr, Al, V) 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 The chipping cannot be prevented sufficiently due to the shortage.

(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 rotary table is provided, cathode electrodes (evaporation sources) are provided on opposite sides of the rotary table, and a metal V is disposed on one side as a cathode electrode (evaporation source). Uses an arc ion plating apparatus in which a Cr—Al—V alloy having a predetermined composition is arranged as a cathode electrode (evaporation source), and the outer peripheral portion is located at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus. A plurality of tool bases are mounted in a ring shape along with the rotation of the rotary table with the atmosphere inside the apparatus being a nitrogen atmosphere, and the thickness of the hard coating layer formed by vapor deposition is uniformized. For the purpose of rotating the tool base itself, basically, first, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of the Cr—Al—V alloy, and the surface of the tool base is formed. After the (Cr, Al, V) N layer is deposited with an average layer thickness of 1 to 5 μm as a lower layer,
The metal that is the cathode electrode (evaporation source) while stopping the arc discharge between the cathode electrode (evaporation source) of the Cr—Al—V alloy and the anode electrode, and subsequently maintaining the atmosphere in the apparatus in a 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,
Further, the VNO layer, the VO layer, and the VN layer are deposited and formed by repeating the same procedure as described above, so that the VNO layer and the VO layer are alternately stacked, and the VNO layer is interposed between the VN layer and the VO layer. An upper layer having a target overall layer thickness (1 to 5 μm) having a laminated structure in which layers are interposed can be formed by vapor deposition.

(E) The coated tool formed by vapor-depositing the hard coating layer composed of the lower layer, the interlayer adhesion layer, and the upper layer of the laminated structure is stainless steel, high manganese steel, and further mild steel having high viscosity and adhesion. Even when cutting difficult-to-cut materials such as high cuts with high loads and heavy cutting conditions such as high feed, the lower layer (Cr, Al, V) N layer has excellent high-temperature hardness and heat resistance The upper layer having a laminated structure has the excellent surface slipping property of the VO layer and the high temperature strength of the VN layer, and the VO layer is interposed by the VNO layer. And the wear resistance of the VN layer is improved, and the bonding strength between the layers is also improved. As a result, the entire upper layer not only has excellent surface slipperiness, but also has excellent high temperature strength and wear resistance. Like this As a whole, the hard coating layer made of steel has a higher temperature strength, a superior surface slipperiness and wear resistance, and a sufficient surface between the difficult-to-cut material and the chips. Since slipperiness is ensured and heavy cutting is performed with the stickiness and reactivity of difficult-to-cut materials and chips to the cutting edge surface being significantly reduced, chipping occurs at the cutting edge. It will disappear, and will exhibit excellent wear resistance 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) having an average layer thickness of 1-5 μm, and
Composition _{formula: (Cr 1-X-Y} Al X V Y) N ( provided that an atomic ratio, X is 0.30 to 0.60, Y represents a 0.05 to 0.30) and Cr satisfying a A lower layer composed of a composite nitride layer of Al and V;
(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 forms a hard coating layer constituted by (a) and (b) described above and exhibits excellent chipping resistance in heavy cutting of difficult-to-cut materials. .

  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) The Al component is a component of the constituting composition and average layer thickness lower layer of the lower layer _{(Cr 1-X-Y Al} X V Y) N improves high-temperature hardness and heat resistance in the hard coating layer In addition, the Cr component has the effect of improving the high temperature strength, and the V component has the effect of improving the lubricity (surface slipperiness), but the X value indicating the proportion of Al occupies the total amount of Cr and V. If the ratio (atomic ratio, hereinafter the same) is less than 0.30, the ratio of Cr becomes relatively large, and the predetermined high-temperature hardness and heat resistance cannot be ensured, which reduces the wear resistance. On the other hand, when the X value indicating the Al ratio exceeds 0.60, the Cr content ratio is relatively decreased, and the high temperature strength required for heavy cutting of difficult-to-cut materials can be secured. X. Since it becomes difficult to prevent occurrence of chipping, X The value is set to 0.30 to 0.60, and if the Y value indicating the ratio of V is less than 0.05 in the ratio of the total amount of Al and Cr, desired lubrication characteristics (surface slipperiness) are obtained. On the other hand, if the Y value exceeds 0.30, the high-temperature strength suddenly decreases, so the Y value was set to 0.05 to 0.30.

  Further, if the average layer thickness is less than 1 μm, it is insufficient to exhibit its excellent wear resistance over a long period of time, whereas if the average layer thickness exceeds 5 μm, the above-mentioned high viscosity is difficult. In the heavy cutting of the cutting material, chipping is likely to occur at the cutting edge, so the average layer thickness was set to 1 to 5 μm.

(B) Single layer average layer thickness of the vanadium nitride layer (VN layer) constituting the alternate layer structure of the upper layer The VN layer constituting the alternate layer structure of the upper layer of the hard coating layer itself has excellent high-temperature strength. 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 if the average layer thickness exceeds 2 μm, In the heavy cutting of the material, the lubricating properties (surface slipperiness) required for the upper layer of the hard coating layer cannot be fully exhibited, and the high temperature hardness of the hard coating layer also decreases, which is wear resistant. The average layer thickness was determined to be 0.4 to 2 μm.

(C) 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. The Cr, Al, V) N layer is protected from the high-temperature heated work material and chips and exhibits an effect of suppressing the occurrence of chipping, but if the average layer thickness is less than 0.4 μm, the effect On the other hand, if the average layer thickness exceeds 2 μm, the chipping is likely to occur even if the high temperature strength is reinforced by the alternately laminated structure with the VN layer. Layer thickness is 0.4-2μm It was determined.

(D) Single layer average layer thickness of the vanadium oxynitride layer (VNO layer) constituting the laminated structure of the upper layer The VNO layer is formed by forming the VO layer or 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.

(E) Overall average layer thickness of the upper layer If the overall average layer thickness of the upper layer is less than 1 μm, the hard coating layer cannot sufficiently exhibit excellent surface slipperiness in heavy cutting of difficult-to-cut materials. The effect of reducing the adhesion and reactivity of the cutting material (difficult-to-cut material) and chips to the cutting edge surface cannot be expected. On the other hand, if the overall average layer thickness exceeds 5 μm, the high temperature hardness of the hard coating layer Decreases rapidly and wear resistance becomes insufficient, so the total average layer thickness is set to 1 to 5 μm.

  In the coated tool of the present invention, the lower (Cr, Al, V) N layer constituting the hard coating layer has excellent high-temperature hardness, heat resistance, high-temperature strength, and surface slipperiness, and the VNO layer Since the upper layer composed of an alternating layer structure with intervening layers has excellent high temperature strength, surface slipperiness, and wear resistance as a whole, the hard coating layer as a whole has excellent high temperature hardness, It has heat resistance, high temperature strength, wear resistance, and even better lubrication characteristics (surface slipperiness). As a result, it is particularly difficult to cut difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel with high viscosity and adhesion. Even heavy cutting with high heat and high load 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 predetermined distance in the radial direction from the central axis on the rotary table in the apparatus, cathode electrodes (evaporation sources) are arranged on opposite sides across the rotary table, one of which Is arranged with a metal V as a cathode electrode (evaporation source), and a Cr-Al-V alloy for forming a lower layer having a predetermined composition as a cathode electrode (evaporation source) on the other side.
(B) First, the inside of the apparatus is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the lower electrode forming Cr—Al—V alloy of the cathode electrode and the anode electrode, whereby the surface of the tool base is placed on the Cr—Al -Bombarded with V alloy,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and An arc discharge is generated by passing a current of 120 A between the Cr—Al—V alloy of the cathode electrode and the anode electrode, and the target composition and target layer thickness shown in Tables 3 and 4 are formed on the surface of the tool base. The (Cr, Al, V) N layer as the lower layer is deposited with an average layer thickness of 1 to 5 μm, and then an arc between the cathode electrode (evaporation source) and the anode electrode of the Cr—Al—V alloy is formed. Stop discharging,
(D) Subsequently, while maintaining the atmosphere in the apparatus in a 2 Pa nitrogen atmosphere, a current of 120 A was passed between the metal V as the cathode electrode (evaporation source) and the anode electrode to generate arc discharge, and 3. After vapor-depositing a VN layer having a target layer thickness shown in Table 4, arc discharge between the metal V and the anode electrode is stopped, and at the same time, supply of nitrogen gas into the apparatus is stopped. The inside 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, these tool bases A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plating shown in FIG. Insert the Cr-Al-V alloy with various compositions as the cathode electrode (evaporation source), and first evacuate the apparatus and keep it at a vacuum of 0.1 Pa or less with a heater. After heating the inside of the apparatus to 500 ° C., a DC bias voltage of −1000 V is applied to the tool base, and a current of 100 A is applied between the Cr—Al—V alloy of the cathode electrode and the anode electrode to cause arc discharge. Thus, the surface of the tool base is bombarded with the Cr—Al—V alloy, and then nitrogen gas is introduced into the apparatus as a reaction gas to create a reaction atmosphere of 3 Pa, and the tool base is marked. The bias voltage is reduced to -100V, and arc discharge is generated between the cathode electrode and the anode electrode of the Cr-Al-V alloy, so that the tool bases A-1 to A-10 and B-1 to B are generated. A conventional surface as a conventional coating tool is formed by vapor-depositing a (Cr, Al, V) N layer having the target composition and target layer thickness shown in Tables 5 and 6 on each surface of -6 as a hard coating layer. Coated throwaway chips (hereinafter referred to as conventional coated chips) 1 to 16 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 / SUS316 lengthwise equidistant 4 round grooved round bars,
Cutting speed: 200 m / min. ,
Cutting depth: 3.5 mm,
Feed: 0.25 mm / rev. ,
Cutting time: 5 minutes,
Stainless steel dry interrupted cutting test (normal cutting is 1.5 mm) under the above conditions (cutting condition A),
Work material: JIS / S15C round bar,
Cutting speed: 220 m / min. ,
Cutting depth: 4 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-cut cutting test of mild steel under the above conditions (cutting condition B) (normal cutting is 1.5 mm),
Work material: JIS · SCMnH1 lengthwise equidistant four round grooved round bars,
Cutting speed: 180 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes,
The high-manganese steel dry interrupted high-feed cutting test (normal feed is 0.25 mm / rev.) Under the above conditions (cutting condition C). It 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 tool base forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm are formed, and further, the three kinds of round bar sintered bodies are shown in Table 8 by grinding. In combination, the diameter x length of the cutting edge is 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm, respectively, and each is made of a WC-based cemented carbide with a 4-flute square shape with 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, a lower layer composed of a (Cr, Al, V) N layer having the target composition and target layer thickness shown in Table 9, and a VN layer having a single target layer thickness also shown in Table 9 The surface coating cemented carbide end mill of the present invention (hereinafter referred to as the coated tool) of the present invention is formed by vapor-depositing a hard coating layer composed of an upper layer (having a target total layer thickness) having a laminated structure of a VNO layer and a VO layer. (Referred to as the present invention coated end mill) 1 to 8 were produced.

  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. And by depositing a hard coating layer comprising a (Cr, Al, V) N layer having the target composition and target layer thickness shown in Table 10 under the same conditions as in Example 1 above, Conventional surface-coated carbide end mills (hereinafter referred to as conventional coated end mills) 1 to 8 were produced, 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-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 60 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 200 mm / min,
Stainless steel dry-type high-grooving groove cutting test (normal groove depth is 3 mm),
About this invention coated end mills 4-6 and conventional coated end mills 4-6,
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 75 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 280 mm / min,
Dry high feed groove cutting test of mild steel under normal conditions (normal table feed is 140 mm / min),
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 × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 60 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 180 mm / min,
High-manganese steel dry-type high-grooving groove cutting test under normal conditions (normal groove depth is 10 mm),
In each groove cutting test, the cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge reached 0.1 mm, which is a guide for the service life. The measurement results are shown in Table 9 and Table 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 tool bases (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. The lower layer consisting of the (Cr, Al, V) N layer of the target composition and target layer thickness shown in Table 11 and the single layer target also shown in Table 11 under the same conditions as in Example 1 above. The present invention as a coated tool of the present invention is formed by vapor-depositing a hard coating layer composed of an upper layer (having a target total layer thickness) having a layer thickness, an alternately laminated structure of a VN layer and a VO layer via a VNO layer. Surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 8 were produced.

  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. A hard coating layer composed of a (Cr, Al, V) N layer having the target composition and target layer thickness shown in Table 12 is formed by vapor deposition under the same conditions as in Example 1 above. Thus, conventional surface coated carbide drills (hereinafter referred to as conventional coated drills) 1 to 8 as conventional coated tools were manufactured, respectively.

Next, of the present invention coated drills 1 to 8 and the conventional coated drills 1 to 8, the present invention coated drills 1 to 3 and the conventional coated drills 1 to 3 are:
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 70 m / min. ,
Feed: 0.38 mm / rev,
Hole depth: 8 mm,
Stainless steel wet high feed drilling cutting test under normal conditions (normal feed is 0.2 mm / rev),
About this invention coated drill 4-6 and conventional coated drills 4-6,
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 100 m / min. ,
Feed: 0.45 mm / rev,
Hole depth: 20 mm,
Wet high feed drilling test of mild steel under normal conditions (normal feed is 0.25 mm / rev),
About this invention covering drills 7 and 8 and conventional covering drills 7 and 8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 125 m / min. ,
Feed: 0.45 mm / rev,
Hole depth: 28 mm,
Wet high feed drilling test of high manganese steel under normal conditions (normal feed is 0.25 mm / rev),
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.

  (Cr, Al, V) N constituting the hard coating layer of the present coated tips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated tool obtained as a result. The composition of the layer (lower layer) and the conventional coating tip 1-16 as a conventional coating tool, the conventional coating end mills 1-8, and the hard coating comprising the (Cr, Al, V) N layer of the conventional coating drills 1-8 The composition of the layers was measured by energy dispersive X-ray analysis using a transmission electron microscope, and each showed substantially the same composition as the target 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 7 and 9-12, the coated tools of the present invention are particularly heavy, such as high cutting and high feed of difficult-to-cut materials such as stainless steel and high manganese steel, and also mild steel with high viscosity and adhesion. Even in cutting under the cutting conditions, the (Cr, Al, V) N layer, which is the lower layer of the hard coating layer, is firmly adhered and bonded to the surface of the tool base, and has excellent high temperature hardness, heat resistance, high temperature strength, and Surface slipperiness, and a superior surface slip between the work material and the chips by the upper layer composed of an alternately laminated structure of vanadium nitride layers and vanadium oxide layers with vanadium oxynitride layers interposed The high temperature strength and wear resistance of the upper layer as a whole are maintained at the same time, and thus 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 the (Cr, Al, V) N layer, the work material (hard-cutting material) and the chips in the heavy cutting of the difficult-to-cut material Since the adhesion and reactivity between the hard coating layer and the hard coating layer are further increased, and the adhesion of the hard coating layer to the tool substrate surface is insufficient, chipping occurs in the cutting edge portion, It is clear that the service life is reached in a relatively short time.

  As described above, the coated tool of the present invention exhibits excellent chipping resistance not only for cutting of general steel and ordinary cast iron, but particularly for heavy cutting of the above difficult-to-cut materials, and for a long time. Since it shows excellent cutting performance, it can fully satisfactorily cope with the FA of the cutting apparatus, labor saving and energy saving of cutting, and cost reduction.

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. It is a schematic explanatory drawing of a normal arc ion plating apparatus.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) having an average layer thickness of 1-5 μm, and
Composition _{formula: (Cr 1-X-Y} Al X V Y) N ( provided that an atomic ratio, X is 0.30 to 0.60, Y represents a 0.05 to 0.30) and Cr satisfying a A lower layer composed of a composite nitride layer of Al and V;
(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 in which the hard coating layer is excellent in heavy cutting of difficult-to-cut materials, which is formed by forming the hard coating layer configured as described above in (a) and (b).

Images