JP2008188736A - Surface coated cutting tool with excellent chipping resistance due to hard coating layer in heavy cutting of difficult-to-cut materials - Google Patents

Abstract

Provided is a surface-coated cutting tool that exhibits excellent chipping resistance in a hard coating layer in heavy cutting of difficult-to-cut materials.
(A) Al and Cr content between the highest Al content point and the lowest Al content point along the layer thickness direction on the surface of the tool base (a) having an average thickness of 1 to 5 μm. Is a composition change (Cr, Al) N layer or composition change (Cr, Al, M) N layer (where M is an element of the periodic table 4a, 5a, 6a group excluding Cr, Si , B or Y selected from one or more additional components), (b) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm, (c) A surface-coated cutting tool formed by forming an upper layer composed of a vanadium oxide layer having an average layer thickness of 0.4 to 2 μm, and a hard coating layer composed of (a) to (c) above.
[Selection figure] None

Description

  This invention has excellent chipping resistance and lubrication with an excellent 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) that exhibits the properties.

  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, shouldering, etc. of the work material, etc. A slow-away end mill tool that performs cutting work in the same manner as an end mill is known.

In addition, as a 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-P Al _P ) N or composition formula: ((Cr _1-Q M _Q ) _1-P Al _P ) N (where M is a periodic table 4a, 5a, 6a excluding Cr 1 or 2 or more kinds of additive components selected from group elements, Si, B, and Y, and P and Q indicate the content ratio of Al component and M component by atomic ratio)
Physical vapor deposition of a hard coating layer composed of a composite nitride layer of Cr and Al or a composite nitride layer of Cr, Al and M (hereinafter collectively referred to as (Cr, Al, M) N) And the (Cr, Al, M) N layer, which is a hard coating layer of the coated tool, has a high-temperature hardness due to Al as a constituent component, a high-temperature strength due to the Cr, The heat resistance is improved by the coexistence of Cr and Al. Furthermore, as the M component, one or two elements selected from the elements of groups 4a, 5a, and 6a of the periodic table excluding Cr, Si, B, and Y When containing more than seeds, the hard coating layer has improved wear resistance, high temperature oxidation resistance, and other characteristics, so it can be used for continuous cutting and intermittent cutting of various general steels and ordinary cast iron. It is also known to show excellent cutting performance when That.

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. Cr-Al alloy or Cr-Al-M alloy having a predetermined composition corresponding to the target composition of the hard coating layer (hereinafter collectively referred to as Cr-Al-M alloy) Is generated between the cathode electrode (evaporation source) and the anode electrode, for example, at a current of 90 A, and simultaneously nitrogen gas is introduced into the apparatus as a reaction gas, for example, a reaction atmosphere of 2 Pa, for example. On the other hand, a hard coating layer composed of a (Cr, Al, M) N layer of the target composition is applied to the surface of the tool base under the condition that a bias voltage of, for example, −100 V is applied. It is also known to be produced by vapor deposition.
JP 9-41127 A Japanese Patent Laid-Open No. 10-25566 JP 2004-106183 A JP 2004-269985 A Japanese Patent Laying-Open No. 2005-330539 JP 2006-82209 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. 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 especially difficult to cut stainless steel, high manganese steel, and mild steel with high chip viscosity and easy adhesion 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, M) N layers constituting the hard coating layers of the conventional coated tool formed using a conventional arc ion plating apparatus as shown in FIG. The structure shown in FIG. 1 (a) is a schematic plan view and FIG. 1 (b) is a schematic front view. Arc ion plating apparatus, that is, a base mounting rotary table is provided at the center of the apparatus, and a Cr-Al-M alloy having a relatively high Al content is provided on one side and the other side is provided with the rotary table interposed therebetween. An arc ion plating apparatus in which a Cr—Al—M alloy having a low Al content is used as a cathode electrode (evaporation source) and is opposed to the central axis on the rotary table of the apparatus at a predetermined distance in the radial direction. A plurality of substrates are attached in a ring shape along the outer periphery of the substrate, and in this state, the atmosphere inside the apparatus is set as a nitrogen atmosphere, the rotary table is rotated, and the thickness of the hard coating layer formed by vapor deposition is made uniform. When the substrate itself rotates, arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides to form a (Cr, Al, M) N layer on the surface of the substrate. In the resultant (Cr, Al, M) N layer, the base body arranged in a ring shape on the rotary table is a cathode electrode of a Cr—Al—M alloy having a relatively high Al content on the one side. When the closest point to the evaporation source), the highest Al content point was formed in the layer, and the substrate was closest to the cathode electrode of the above-mentioned relatively low Al content Cr-Al-M alloy. Al in the layer at the time A low content point is formed, and by rotation of the rotary table, the highest Al content point and the lowest Al content point appear alternately in the layer thickness direction along the layer thickness direction, and the Al highest content point is The lowest Al content point, and the component concentration distribution structure in which the Al content continuously changes from the lowest Al content point to the highest Al content point.

(B) In the (Cr, Al, M) N layer (hereinafter referred to as composition change (Cr, Al, M) N layer) having the repeated continuous change component concentration distribution structure of (a), the above substrate is made of tungsten carbide ( In the following, after specifying a substrate made of a cemented carbide alloy or titanium carbonitride (hereinafter referred to as TiCN) based cermet (hereinafter collectively referred to as a cemented carbide substrate). The ratio of the Al content in the Cr-Al-M alloy that is the cathode electrode (evaporation source) on the side to the total amount of Cr and M is 0.70 to 0.95 in atomic ratio, and the other side The Al content in the Cr—Al—M alloy, which is the cathode electrode (evaporation source), is relatively low, and is also the ratio of the total amount of Cr and M, and the atomic ratio is 0.50 to 0.65. At the same time, the rotating tape on which the carbide substrate is mounted. By controlling the rotational speed of the cable,
The Al highest content point, the composition _{formula: (Cr 1-X Al X} ) N or composition _{formula: ((Cr 1-Z M} Z) 1-X Al X) N ( where, M is the period except for the Cr Table 4a, 5a, 6a group elements, Si, B, Y one or more additive components selected from among them, X represents Al content, Z represents M content Respectively, and the atomic ratio is 0.70 ≦ X ≦ 0.95, 0 <Z ≦ 0.30),
The Al minimum content point is the composition formula: (Cr _1−α Al _α ) N or the composition formula: ((Cr _1−γ M _γ ) _1−α Al _α ) N (where α is the Al content, γ Represents the content ratio of M, and the atomic ratio is 0.50 ≦ α ≦ 0.65, 0 <γ ≦ 0.30),
And the distance in the thickness direction between the adjacent Al highest content point and Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
In the Al highest content point portion, the Al content is relatively high, so the high-temperature hardness is high. On the other hand, in the Al minimum content point portion, the Al content is higher than the Al highest content point portion. Since the Cr content is low and the Cr content is high, the strength becomes relatively higher, and the distance between the Al highest content point and the Al lowest content point is extremely small. While maintaining strength, it also has high temperature hardness and heat resistance, and further, among the elements of the periodic table 4a, 5a, 6a group excluding Cr, Si, B, Y as M component in the layer When one or more additive components selected from the above are contained, wear resistance, high-temperature oxidation resistance, etc. are further improved, and chipping resistance is improved.

(C) The above composition change (Cr, Al, M) N layer is formed as a lower layer with an average layer thickness of 1 to 5 μm, and an upper layer is formed thereon with vanadium oxide (vanadium oxide, depending on the degree of oxidation, Various compound forms such as VO, V ₂ O ₃ and VO ₂ can be used. However, when these layers are collectively referred to as VO), the VO layer has excellent lubricity, and as a result, heat is generated during cutting. Even when the work material (difficult-to-cut material) and its chips are heated at a high temperature, the cutting edge (the rake face and flank face and the cutting edge ridge line where these two surfaces intersect), the work material and the chip Always has excellent lubricity and welding resistance, the adhesiveness and reactivity of the work material and chips to the cutting edge surface are significantly reduced, and the lower layer (Cr, Al, M) N layer should be well protected.

(D) However, when a VO layer is provided directly on the lower layer composed of the composition change (Cr, Al, M) N layer, the composition change (Cr, Al, M) as the lower layer is provided. The adhesion between the N layer and the VO layer as the upper layer is not sufficient, and the high temperature strength of the VO layer itself as the upper layer is not sufficient, so that the adhesion between the lower layer and the upper layer of the hard coating layer is insufficient. Chipping cannot be sufficiently prevented due to insufficient high-temperature strength of the layer.

(E) A hard coating layer is formed by a laminated structure in which an intermediate layer made of a VN layer is interposed between an upper layer made of the VO layer and a lower layer made of the composition change (Cr, Al, M) N layer. Then, the VN layer compensates for the high temperature strength that the VO layer lacks, and the VN layer has excellent adhesion to both the upper layer composed of the VO layer and the lower layer composed of the composition change (Cr, Al, M) N layer. Therefore, by interposing the intermediate layer made of the VN layer between the upper layer and the lower layer, the bonding strength between the VO layer and the composition change (Cr, Al, M) N layer is also improved, and therefore, it has such a laminated structure. The hard coating layer has excellent lubricity and welding resistance provided by the VO layer, and the VN layer is provided to improve the bonding strength between the layers. As a result, the hard coating layer is further improved. Excellent chipping resistance To become that as shown.

(F) The hard coating layer is, for example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. A rotary table is provided, a cathode electrode (evaporation source) is provided across the rotary table, and a metal V is disposed on one side as a cathode electrode (evaporation source), and along the rotary table and from the metal V A cathode electrode (evaporation source) of a Cr—Al—M alloy having a relatively high Al content is disposed on one side at a position 90 degrees apart, and a Cr—Al— layer having a relatively low Al content is disposed on the other side. Using a vapor deposition apparatus in which an M alloy is disposed as a cathode electrode (evaporation source) opposite to each other, a plurality of tool bases are formed in a ring shape along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table. In In this state, the rotating table is rotated by setting the atmosphere inside the apparatus as a nitrogen atmosphere, and the tool base itself is rotated for the purpose of uniformizing the thickness of the hard coating layer to be deposited, and firstly opposed to the surface. An arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of each Cr—Al—M alloy, and a composition change (Cr, Al, M) N layer is formed as a lower layer on the surface of the tool base. After vapor deposition with an average layer thickness of 1-5 μm,
Arc discharge between the cathode electrode (evaporation source) of each Cr-Al-M alloy and the anode electrode is stopped, and then the cathode atmosphere (evaporation source) is maintained while the apparatus atmosphere is maintained in a nitrogen atmosphere. An arc discharge is generated between the metal V and the anode electrode, and a VN layer is formed by vapor deposition 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, 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,
Thereafter, supply of oxygen gas into the apparatus is started to switch the atmosphere in the apparatus to an oxygen atmosphere, and arc discharge is again generated between the metal V as the cathode electrode (evaporation source) and the anode electrode, and the VN layer By depositing a VO layer with an average layer thickness of 0.4-2 μm,
A hard coating layer having a laminated structure of a composition change (Cr, Al, M) N layer as a lower layer, a VN layer as an intermediate layer, and a VO layer as an upper layer can be formed by vapor deposition.

(G) A coated tool formed by vapor-depositing a hard coating layer composed of the lower layer, the intermediate layer and the upper layer is particularly difficult to cut stainless steel, high manganese steel, and mild steel with high viscosity and adhesion. Even when the material is machined under heavy cutting conditions such as high cutting with high load and high feed, the composition change (Cr, Al, M) N layer as the lower layer has excellent high-temperature hardness, heat resistance, When the layer has high-temperature strength or contains an M component in the layer, the wear resistance, high-temperature oxidation resistance, etc. are further improved, and the upper layer has excellent lubricity and resistance to the VO layer. In addition to having weldability, the VN layer also improves the bonding strength between the lower layer and the intermediate layer. As a result, the hard coating layer having such a structure as a whole has excellent lubricity and welding resistance. High temperature strength, wear resistance, heat resistance, high temperature resistance Chipping at the cutting edge because heavy cutting is performed with significantly reduced stickiness and reactivity of difficult-to-cut materials and chips to the cutting edge surface. Generation of excellent wear resistance over a long period of time.
The research results shown in (a) to (g) above were obtained.

This invention was made based on the above research results,
“(1) On the surface of a tool base made 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 Cr contents continuously change from the point to the Al lowest content point, from the Al lowest content point to the Al highest content point,
Furthermore, the Al highest content point is the composition formula: (Cr _1-X Al _X ) N (where X represents the content ratio of Al, and the atomic ratio is 0.70 ≦ X ≦ 0.95),
The Al minimum content point is a composition formula: (Cr _1−α Al _α ) N (where α represents the Al content ratio, and is an atomic ratio of 0.50 ≦ α ≦ 0.65),
A lower layer composed of a composite nitride layer of Cr and Al, wherein the distance between the Al highest content point and the Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
(B) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm,
(C) an upper layer comprising a vanadium oxide layer having an average layer thickness of 0.4-2 μm,
A surface-coated cutting tool that exhibits a chipping resistance in which a 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) to (c).
(2) On the surface of the tool base made 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 Cr contents continuously change from the point to the Al lowest content point, from the Al lowest content point to the Al highest content point,
Further, the highest Al content point is the composition formula: ((Cr _1−Z M _Z ) _1−X Al _X ) N (where M is an element of groups 4a, 5a and 6a of the periodic table excluding Cr, One or more additive components selected from Si, B, and Y are shown, X is the Al content, Z is the M content, and the atomic ratio is 0.70 ≦ X ≦ 0.95, 0 <Z ≦ 0.30),
The Al minimum content point is the composition formula: ((Cr _1-γ M _γ ) _1-α Al _α ) N (where α represents the Al content rate, γ represents the M content rate, and the atomic ratio, 0.50 ≦ α ≦ 0.65, 0 <γ ≦ 0.30),
A lower layer composed of a composite nitride layer of Cr, Al, and M, wherein the distance between the Al highest content point and the Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
(B) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm,
(C) an upper layer comprising a vanadium oxide layer having an average layer thickness of 0.4-2 μm,
A surface-coated cutting tool that exhibits a chipping resistance in which a 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) to (c).
(3) The hard coating layer is formed by heavy cutting of the difficult-to-cut material according to (2), wherein the additive component M is one or more selected from Si, B, and Y. A surface-coated cutting tool with excellent chipping resistance. "
It has the characteristics.

  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 the highest Al content point The composition component (Cr, Al, M) that constitutes the lower layer The Al component, which is a component of the N layer, improves the high-temperature hardness in the hard coating layer, The Cr component has the effect of improving the high-temperature strength and improving the heat resistance by coexistence of Cr and Al. Further, of the M component, the periodic table 4a, 5a, 6a excluding Cr Elements, Si and B have the effect of improving the wear resistance of the hard coating layer, and Y has the function of improving the high temperature oxidation resistance of the hard coating layer, but Al at the highest Al content point. If the ratio (X value) exceeds 0.95 in the total amount of Cr and M (atomic ratio), the ratio of Cr becomes too small and the high-temperature strength rapidly decreases, and chipping (finely) Chipping) or the like is likely to occur, while the ratio (X value) is also 0. If it is less than 70, the proportion of Al becomes too low to ensure the desired excellent high-temperature hardness and heat resistance, and the Z value indicating the M content is the total amount of Cr. If the proportion (atomic ratio) exceeds 0.30, the wear resistance, high-temperature oxidation resistance, etc. are improved, but the high-temperature strength required for heavy cutting of difficult-to-cut materials cannot be secured, Since it becomes difficult to prevent occurrence of chipping, the X value was set to 0.70 to 0.95 and the Z value was set to 0.30 or less.

(B) Composition of the lowest Al content point As described above, the highest Al content point is excellent in high-temperature hardness, but on the other hand, the high-temperature strength is inferior. For this purpose, the Al content is relatively high, and the Al minimum content points that have high high-temperature strength are alternately interposed in the thickness direction. Therefore, the Al content (α value) is If the ratio (atomic ratio) in the total amount of Cr and M exceeds 0.65, the desired excellent high-temperature strength cannot be ensured, while the content ratio (α value) is less than 0.50. Since the ratio of Cr is relatively large and the Al minimum content point cannot be provided with a desired high temperature hardness, the α value is set to 0.50 to 0.65, and About the content ratio (γ value) of M component Is a γ value for the same reasons specified to 0.30 as in the Al highest containing point.

(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. High temperature characteristics and high temperature strength cannot be ensured, and if the distance exceeds 0.1 μm, each point has a defect, that is, the highest Al content point is insufficient high temperature strength, and the lowest Al content point is high temperature. Insufficient characteristics appear locally in the layer, which makes it easier for chipping to occur at the cutting edge and promotes the progress of wear. Therefore, the interval is set to 0.03 to 0.1 μm. It was.

(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) An intermediate layer composed of a vanadium nitride layer (VN layer) The VN layer constituting the intermediate layer of the hard coating layer has an excellent high-temperature strength in itself and compensates for the lack of the high-temperature strength of the VO layer. If the average layer thickness 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, it is necessary for the upper layer of the hard coating layer in heavy cutting of difficult-to-cut materials. The lubrication characteristics (surface slipperiness) cannot be sufficiently exhibited, and the high temperature hardness of the hard coating layer also decreases, which causes a decrease in wear resistance. .4-2 μm.

(C) Upper layer composed of vanadium oxide layer (VO layer) The VO layer constituting the upper layer of the hard coating layer has excellent lubricity and welding resistance, and is a work material (hard-to-cut material) and chips The adhesiveness and reactivity with respect to the material are extremely low, and this is maintained without changing even when the work material is heated at the time of cutting. Therefore, the composition change (Cr, Al, M) N layer as the lower layer is formed. Protects from the high-temperature heated work material and chips and exerts an action of suppressing the occurrence of chipping thereof, but if the average layer thickness is less than 0.4 μm, the desired effect cannot be obtained in the action, On the other hand, if the average layer thickness exceeds 2 μm and becomes too thick, chipping is likely to occur even if the high-temperature strength is reinforced with the laminated structure with the VN layer, so the average layer thickness is set to 0.4 to 2 μm. It was.

  In the coated tool of the present invention, the lower layer (Cr, Al, M) N layer constituting the hard coating layer has excellent high temperature hardness, heat resistance, high temperature strength, or even better wear resistance. It has high temperature oxidation resistance, and the upper layer formed as a laminated structure with a VN layer intervening has excellent lubricity (surface slipperiness), welding resistance, and high temperature strength. The layer as a whole has excellent high temperature hardness, heat resistance, high temperature strength, etc., as well as excellent lubricity and welding resistance. As a result, especially stainless steel and high manganese steel with high viscosity and adhesion In addition, it is accompanied by a large heat generation of difficult-to-cut materials such as mild steel, and exhibits excellent chipping resistance even during heavy cutting with high load, and exhibits excellent wear resistance over a long period of time. is there.

  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, and after sintering, tool bases A-1 to A-10 made of WC-based cemented carbide with ISO standard / CNMG120408 chip shape 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 Then, the green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base B made of TiCN-based cermet having an ISO standard / CNMG120408 chip shape was obtained. -1 to B-6 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, and provided with cathode electrodes (evaporation sources) on opposite sides across the rotary table. Has a metal V as a cathode electrode (evaporation source), and has a relatively high Al content on the one side of the position along the rotary table and 90 degrees away from the metal V. The cathode electrode (evaporation source) of the alloy is disposed opposite to the other side as a cathode electrode (evaporation source) of a Cr-Al-M alloy having a relatively low Al content,
(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 cathode electrode and the anode electrode of each of the Cr—Al—M alloys. -Bombarded with M 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 each of the Cr—Al—M alloys of the cathode electrode and the anode electrode, so that Table 3 and Table 4 are formed on the surface of the tool base along the layer thickness direction. The highest Al content point and the lowest Al content point of the target composition shown in FIG. 3 are alternately repeated at the target intervals shown in Tables 3 and 4, and from the highest Al content point to the lowest Al content point, the lowest Al content point. The composition change (Cr, Al, having a component concentration distribution structure in which the Al (Cr) content continuously changes from the content point to the Al maximum content point and having the target layer thicknesses also shown in Tables 3 and 4 M) N Was vapor deposited as the lower layer of the hard coating layer with an average layer thickness of 1 to 5 [mu] m, the stop arc discharge between the cathode electrode (vapor source) and the anode electrode of each Cr-Al-M alloy,
(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 the VN layer having the target layer thickness shown in Table 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 supply of nitrogen gas into the apparatus is stopped. Vacuum for about 10 seconds,
(E) After that, 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 flowing a current of VO, and a VO layer having the target layer thickness shown in Tables 3 and 4 is formed on the VN layer by vapor deposition. Then, the arc discharge between the metal V and the anode electrode is performed. , Stop supplying oxygen gas into the device, evacuate the device for about 10 seconds,
The hard coating layer was formed by vapor deposition according to the above (a) to (e), and the present surface coated throwaway tips (hereinafter referred to as the present coated tips) 1 to 39 as the coated tools of the present invention were produced.

  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. The device was charged and a Cr-Al-M alloy having a predetermined composition was mounted as a cathode electrode (evaporation source). After heating to 500 ° C., a DC bias voltage of −1000 V is applied to the tool base, and a current of 100 A is passed between the cathode electrode Cr—Al—M alloy and the anode electrode to generate arc discharge, Thus, the surface of the tool base is bombarded with the Cr—Al—M alloy, then nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 3 Pa, and a via applied to the tool base. The voltage is lowered to -100 V to generate an arc discharge between each cathode electrode and anode electrode having the predetermined composition, whereby each of the tool bases A-1 to A-10 and B-1 to B-6 is generated. A surface-coated throwaway tip as a comparative coating tool (by coating a hard coating layer comprising (Cr, Al, M) N layers having the target compositions and target layer thicknesses shown in Tables 5 and 6 on the surface) (Hereinafter referred to as comparative 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 39 and the comparative coated chips 1 to 16 are as follows.
Work material: JIS · SCMnH1 lengthwise equidistant four round grooved round bars,
Cutting speed: 225 m / min. ,
Cutting depth: 3.5 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes,
Of high manganese steel under the above conditions (cutting condition A), a dry intermittent high cutting test (normal cutting is 1.5 mm),
Work material: JIS / SUS304 round bar,
Cutting speed: 240 m / min. ,
Incision: 2.3 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high-cut cutting test under normal conditions (cutting condition B) (normal cutting is 1.5 mm),
Work material: JIS-S11C lengthwise equal 4 round grooved round bars,
Cutting speed: 240 m / min. ,
Infeed: 3.2 mm,
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes,
Was performed in a dry interrupted high feed cutting test (normal feed is 0.25 mm / rev.), And the flank wear width of the cutting edge was measured in any cutting test. . The measurement results are shown in Tables 7 and 8.

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 .8 μm Co powder was prepared, each of these raw material powders was blended in the blending composition shown in Table 9, and then added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressed into a predetermined shape 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 were formed, and further, the three types of round rod sintered bodies were ground by grinding as shown in Table 9. 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, the Al minimum content point and the Al maximum content point of the target composition shown in Table 10 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 10, and It has a component concentration distribution structure in which the Al (Cr) 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 10 The composition change of the target layer thickness (Cr, Al, M) The lower layer composed of the N layer and the hard coating layer composed of the VN layer and the VO layer of the target layer thickness also shown in Table 10 are formed by vapor deposition. Invented coated tool Of the present invention the surface coating cemented carbide end mill (hereinafter, the present invention refers to the coating end mill) 1-27 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 hard coating layer composed of the (Cr, Al, M) N layer having the target composition and the target layer thickness shown in Table 12 is vapor-deposited. Surface-coated carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 10 were produced.

Next, with respect to the present invention coated end mills 1 to 27 and comparative coated end mills 1 to 10,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 55 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 250 mm / min,
High-manganese steel dry-type high-grooving groove cutting test under normal conditions (cutting condition D) (normal groove depth is 3 mm),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 64 m / min. ,
Groove depth (cut): 3.5 mm,
Table feed: 240 mm / min,
(Cutting condition E) of stainless steel dry type high feed groove cutting test (normal table feed is 120 mm / min),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S11C plate,
Cutting speed: 45 m / min. ,
Groove depth (cut): 8 mm,
Table feed: 150 mm / min,
Dry high-cut groove cutting test of mild steel under normal conditions (cutting condition F) (normal groove depth is 5 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 Tables 11 and 12, 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. In the same condition as in Example 1 above, the lowest Al content point and the highest Al content point of the target composition shown in Table 13 along the layer thickness direction are alternately set at the target interval shown in Table 13. It has a component concentration distribution structure that repeatedly exists and the Al (Cr) 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 lower layer composed of the target layer thickness composition change (Cr, Al, M) N layer shown in Table 13 and the hard coating layer composed of the VN layer and VO layer of the target layer thickness also shown in Table 13 are deposited. By forming a book The present invention surface coating cemented carbide drills as bright coated tool (hereinafter, the present invention refers to the coating drill) 1-27 were prepared, respectively.

  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, M) N layer having the target composition and target layer thickness shown in Table 15 is formed by vapor deposition under the same conditions as in Example 1 above. Thus, surface coated carbide drills (hereinafter referred to as comparative coated drills) 1 to 10 as comparative coated tools were manufactured, respectively.

Next, about the said invention coated drill 1-27 and the comparative coated drill 1-10,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 75 m / min. ,
Feed: 0.45 mm / rev,
Hole depth: 10 mm,
Wet high feed drilling test of high manganese steel under the above conditions (cutting condition G) (normal feed is 0.2 mm / rev),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 105 m / min. ,
Feed: 0.4 mm / rev,
Hole depth: 10 mm,
Stainless steel wet high feed drilling test under normal conditions (cutting condition H) (normal feed is 0.2 mm / rev),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S11C plate,
Cutting speed: 50 m / min. ,
Feed: 0.35 mm / rev,
Hole depth: 7 mm,
Wet high feed drilling test of mild steel under normal conditions (cutting condition I) (normal feed is 0.2 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 14 and 15, respectively.

As a result, the composition change (Cr, Al, M) constituting the hard coating layers of the present coated chips 1 to 39, the present coated end mills 1 to 27, and the present coated drills 1 to 27 as the present coated tools obtained. ) The composition of the lowest Al content point and the highest Al content point of the N layer (lower layer) was measured by energy dispersive X-ray analysis using a transmission electron microscope. The composition was substantially the same as the highest content point.
Further, the composition of the hard coating layer composed of the (Cr, Al, M) N layers of the comparative coating tips 1 to 16, the comparative coating end mills 1 to 10 and the comparative coating drills 1 to 10 as the comparative coating tool is changed to transmission electron. When measured by an energy dispersive X-ray analysis method using a microscope, each showed substantially the same composition as the target composition.

Furthermore, the composition of the vanadium nitride layer constituting the intermediate layer of the hard coating layer of the present coated tool and the composition of the vanadium oxide layer constituting the upper layer were also measured by energy dispersive X-ray analysis using a transmission electron microscope. The vanadium nitride layer has a structure mainly composed of VN, and the vanadium oxide layer has a mixed structure mainly composed of VO and containing V ₂ O ₃ and VO ₂ .

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

  From the results shown in Tables 7, 8, 11, 12, 14, and 15, all of the coated tools of the present invention have a high cutting depth for difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel, which are particularly highly viscous and sticky. Even under heavy cutting conditions such as high feed and high feed, excellent high-temperature hardening is possible with the composition change (Cr, Al, M) N layer, which is the lower layer of the hard coating layer, firmly bonded to the surface of the tool base. The upper layer comprising a vanadium oxide layer having a heat resistance, a high temperature strength, or in addition to this, an excellent wear resistance, a high temperature oxidation resistance, and a vanadium nitride layer interposed as an intermediate layer, With excellent lubricity and welding resistance between the work material and the chips, it has excellent wear resistance over a long period of time without occurrence of chipping. Layer is (Cr, Al M) In the comparative coated tool which is composed of the N layer and does not include the vanadium nitride layer and the vanadium oxide layer, both of the work material (difficult-to-cut material), the chip, and the hard coating in the heavy cutting of the difficult-to-cut material It is clear that since the adhesiveness and reactivity with the layer are further increased, chipping occurs at the cutting edge and 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 the conventional arc ion plating apparatus used in forming the hard coating layer which comprises a comparative coating tool.

Claims (3)

On the surface of the tool base composed of tungsten carbide base cemented carbide or titanium carbonitride base 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 Cr contents continuously change from the point to the Al lowest content point, from the Al lowest content point to the Al highest content point,
Furthermore, the Al highest content point is the composition formula: (Cr _1-X Al _X ) N (where X represents the content ratio of Al, and the atomic ratio is 0.70 ≦ X ≦ 0.95),
The Al minimum content point is a composition formula: (Cr _1−α Al _α ) N (where α represents the Al content ratio, and is an atomic ratio of 0.50 ≦ α ≦ 0.65),
A lower layer composed of a composite nitride layer of Cr and Al, wherein the distance between the Al highest content point and the Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
(B) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm,
(C) an upper layer comprising a vanadium oxide layer having an average layer thickness of 0.4-2 μm,
A surface-coated cutting tool that exhibits a chipping resistance in which a 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) to (c). On the surface of the tool base composed of tungsten carbide base cemented carbide or titanium carbonitride base 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 Cr contents continuously change from the point to the Al lowest content point, from the Al lowest content point to the Al highest content point,
Further, the highest Al content point is the composition formula: ((Cr _1−Z M _Z ) _1−X Al _X ) N (where M is an element of groups 4a, 5a and 6a of the periodic table excluding Cr, One or more additive components selected from Si, B, and Y are shown, X is the Al content, Z is the M content, and the atomic ratio is 0.70 ≦ X ≦ 0.95, 0 <Z ≦ 0.30),
The Al minimum content point is the composition formula: ((Cr _1-γ M _γ ) _1-α Al _α ) N (where α represents the Al content rate, γ represents the M content rate, and the atomic ratio, 0.50 ≦ α ≦ 0.65, 0 <γ ≦ 0.30),
A lower layer composed of a composite nitride layer of Cr, Al, and M, wherein the distance between the Al highest content point and the Al lowest content point adjacent to each other is 0.03 to 0.1 μm,
(B) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm,
(C) an upper layer comprising a vanadium oxide layer having an average layer thickness of 0.4-2 μm,
A surface-coated cutting tool that exhibits a chipping resistance in which a 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) to (c).   The additive component M is one or more selected from Si, B, and Y, wherein the hard coating layer has excellent resistance to hard cutting in heavy cutting of difficult-to-cut materials. Surface coated cutting tool that demonstrates chipping properties.

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