JP6221872B2 - Surface coated cutting tool - Google Patents

Description

  The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool), and more specifically, for example, a work material that is accompanied by high heat generation such as titanium alloy, heat-resistant alloy, and stainless steel and that has a remarkable weldability to a cutting blade. The present invention relates to a coated tool that exhibits high-temperature stability, heat resistance, wear resistance, and welding resistance with excellent hard coating layers when high-speed cutting is performed.

  In general, coated tools are used for turning and planing of work materials such as various types of steel and cast iron, inserts that can be used detachably attached to the tip of a cutting tool, drilling processing of work materials, etc. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material, etc. Also, inserts are detachably attached and cutting is performed in the same way as solid type end mills Insert type end mill tools are known.

  In recent years, there is a high demand for higher efficiency in cutting metal materials, and it is required to increase the cutting speed. For this reason, it is requested | required that a wear resistance and a fracture | rupture resistance should be improved with respect to the film which coat | covers the tool base | substrate surface of a cutting tool.

Patent Document 1 discloses a hard coating layer based on an aluminum oxide, and Al _1-x M _x (O _1-Y N _Y ) _z (0 ≦ X ≦ 0.5, 0 <Y ≦ 0. 4, Z> 0), and M in this composition is at least one element selected from Ti, Zr, V, Nb, Mo, W, Y, Mg, Si, and B An AlM (ON) hard coating layer is disclosed. Further, the same document discloses that such a hard coating layer is excellent in wear resistance and heat resistance, and can be formed at a substrate temperature of 1000 ° C. or lower, specifically 400 to 600 ° C. Yes.

  Further, Patent Document 2 forms a film on a tool base of a coated tool, and this film is a composite in which one or more first super multi-layer films and one or more second super multi-layer films are alternately laminated. Including a super multi-layer film, wherein the first super multi-layer film is formed by alternately laminating one or more layers each of A1 layers and B layers, and the second super multi-layer film comprises A2 layers and C layers, respectively. It is configured by alternately laminating one or more layers, the A1 layer and the A2 layer are each composed of any one of TiN, TiCN, TiAlN, or TiAlCN, the B layer is composed of TiSiN or TiSiCN, and the C layer Discloses providing a coated tool having a laminated hard coating layer with reduced brittleness problems while maintaining wear resistance and heat resistance by being composed of AlCrN or AlCrCN.

  Further, as another conventional coated tool, for example, an arc ion plating apparatus, which is one of physical vapor deposition apparatuses shown schematically in FIG. 2, is loaded with a tool base, and the tool base is heated to 450 ° C. with a heater. While being heated to a temperature, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which an Al—Cr alloy having a predetermined composition is set under the condition of current: 100 A and simultaneously reacts in the apparatus. Nitrogen gas is introduced as a gas to form a nitrogen atmosphere. On the other hand, by evaporating evaporated particles on the surface of the tool base under the condition that a bias voltage of −200 V is applied (Al, Cr, for example) ) It is also known that a hard coating layer composed of an N layer is formed (see, for example, Patent Document 3).

JP 2010-236092 A International Publication No. 2008/146727 JP 2000-271699 A

  However, the automation of cutting machines in recent years has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting tools have as much influence on the type of work material as possible. However, in a conventional coated tool using a coating layer composed of an (Al, Cr) N layer, there is a tendency to be versatile, that is, a cutting tool capable of cutting as many grades as possible. Is used for cutting at normal cutting speeds of work materials such as steel and cast iron, but titanium alloys, heat-resistant alloys, stainless steel, etc. are accompanied by high heat generation and are applied to the cutting edge. When cutting under high-speed cutting conditions with remarkable impact and weldability, the (Al, Cr) N layer is a hard film, but the film itself may collapse or peel due to its hardness and high residual stress. Questions There are, as a result, occurs rapidly increased in defects in the cutting edge (small chipping), which is at present, leading to a relatively short time service life due.

For example, according to Patent Document 1, although it is possible to improve the wear resistance and heat resistance to some extent, since the problem of such an AlM (ON) hard coating layer shows brittleness, impact during cutting, etc. This causes a problem that the coating itself is broken or peeled off.
Further, even with the hard coating layer of Patent Document 2, even under severe cutting conditions, the individual coatings constituting the laminated structure cannot be sufficiently prevented from being broken or peeled, resulting in a sufficient hard coating. In some cases, the wear resistance of the entire layer could not be obtained.
Therefore, the technical problem to be solved by the present invention, that is, the object of the present invention is to have excellent heat resistance even when cutting titanium alloy, heat-resistant alloy, stainless steel, etc. under high-speed cutting conditions with high heat generation, An object of the present invention is to provide a coated tool that exhibits wear resistance and welding resistance and exhibits excellent cutting performance over a long period of time.

  In view of the above, the inventors of the present invention cut a workpiece with high-temperature heat generation, particularly titanium alloy, heat-resistant alloy, stainless steel, and the like, which has remarkable weldability to the cutting edge under high-speed cutting conditions. In this case, intensive research was conducted to develop a coated tool having a hard coating layer with excellent heat resistance, wear resistance and welding resistance.

As a result, the following new findings were obtained.
(1) The (Al, Cr) (ON) layer has wear resistance, and heat resistance can be improved by containing a predetermined amount of oxygen.
(2) The (Al, Mn) (ON) layer is a very stable substance of Mn oxide itself, and when introduced into the Al oxide, it improves the high-temperature stability of the Al oxide. There is an effect. Furthermore, by further developing this to form a composite oxynitride of Al and Mn, the wear resistance is improved as compared with each oxide. As a result, it exhibits excellent heat resistance, wear resistance, and welding resistance to difficult-to-cut materials that easily generate heat during cutting.
(3) However, when the above-described (Al, Cr) (ON) layer and (Al, Mn) (ON) layer are respectively used alone, the wear resistance can be obtained only by the (Al, Cr) (ON) layer. Even if it can be secured, heat resistance is poor. Conversely, when an (Al, Mn) (ON) layer is used alone, it is practically used as a hard coating layer for cutting tools with poor wear resistance even if heat resistance can be secured. Not right. Further, if it is attempted to increase wear resistance by increasing the thickness of each layer, chipping is likely to occur due to the residual compressive stress generated in the layer, and the cutting performance cannot be maintained over a long period of time.

  Based on such knowledge, the present invention is a base layer, a thin layer A composed of an (Al, Cr) (ON) layer, a thin layer B composed of an (Al, Mn) (ON) layer, an average layer thickness of each layer, It was obtained as a result of detailed analysis of the relationship between the layer thickness of the thin layer A and the thin layer B, the relationship between the total thickness of the hard coating layer and the cutting performance, and specifically, Consists of configuration.

The present invention has been made based on the research results,
“(1) In a surface-coated cutting tool in which a hard coating layer is formed on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.55 to 5.5 μm formed on the surface of the tool substrate; and
Composition formula: (Al _1-e Cr _e ) N (where e represents the content ratio of Cr in the total amount of Al and Cr, and the atomic ratio is 0.25 ≦ e ≦ 0.55) A satisfactory underlayer,
(B) having an average layer thickness of 0.1 to 1.0 μm, and
Composition formula: (Al _1-a Cr _a ) (O _1-b N _b ) (where a represents the content ratio of Cr in the total amount of Al and Cr, and the atomic ratio is 0.25 ≦ a ≦ In addition, b represents the content ratio of N in the total amount of O and N, and the composite nitridation of Al and Ti satisfying the atomic ratio of 0.50 ≦ b ≦ 0.95) A thin layer A composed of physical layers;
(C) having an average layer thickness of 0.05 to 0.5 μm, and
Composition formula: (Al _1-c Mn _c ) (O _1-d N _d ) (where c represents the content ratio of Mn in the total amount of Al and Mn, and the atomic ratio is 0.10 ≦ c ≦ In addition, d represents the content ratio of N in the total amount of O and N, and the composite nitridation of Al and Mn satisfying the atomic ratio of 0.01 ≦ d ≦ 0.50) A thin layer B composed of physical layers,
The thin layer A and the thin layer B are alternately laminated on the foundation layer, and the layer thickness of the foundation layer is thicker than the total layer thickness of the alternate lamination formed on the upper layer. Is a surface-coated cutting tool characterized in that it is thicker than the layer thickness of the thin layer B, and the total layer thickness of the entire hard coating layer is 1.0 to 10.0 μm. "
It is characterized by.

  Next, the reason why the numerical values of the constituent layers of the hard coating layer of the coated tool of the present invention are limited as described above will be described.

(A) Average layer thickness and composition of the underlayer formed on the tool substrate:
Since the thin layer A and the thin layer B, which will be described later, according to the present invention are chemically stable, they are difficult to bond to the tool substrate. That is, since it is difficult for the thin layer A and the thin layer B to obtain high adhesion to the tool base surface, it is necessary to provide a base layer between the thin base A and the tool base. As the underlayer, a nitride excellent in adhesion to the tool base surface is preferably used. When a part of the nitride forming the base layer becomes an oxide, the adhesion to the tool base surface is lowered. Therefore, the nitride formed as the underlayer is required to have a sufficiently high oxidation start temperature and not be oxidized during the formation of the film. When the nitride used for the underlayer is represented by the composition formula: (Al _1-e Cr _e ) N, when the value of e is 0.25 ≦ e ≦ 0.55 in atomic ratio, the oxidation start temperature is Since the temperature is about 1100 ° C., Al is oxidized in a high pressure / high temperature environment during cutting, and a protective film of amorphous Al ₂ O ₃ is formed. Abrasion is excellent.
In addition, if the average thickness of the underlayer is less than 0.55 μm, sufficient wear resistance required for the underlayer cannot be secured, while if it exceeds 5.5 μm, chipping and defects occur. Since it becomes easy, the average layer thickness of the underlayer was determined to be 0.55 to 5.5 μm.
Therefore, it has an average layer thickness of 0.55 to 5.5 μm on the tool base, and the composition formula: (Al _1-e Cr _e ) N (where e is the amount of Cr in the total amount of Al and Cr) An underlayer satisfying a content ratio and satisfying an atomic ratio of 0.25 ≦ e ≦ 0.55) is formed.

(B) Composition of (Al, Cr) (ON) layer constituting thin layer A layer:
The (Al _1-a Cr _a ) (O _1-b N _b ) layer of the thin layer A that constitutes an alternate laminated structure with the thin layer B described later has uniform wear resistance, heat resistance and toughness throughout the layer. However, the Cr component, which is a constituent component, provides excellent high-temperature strength and high-temperature lubricity, and the Al component supplements high-temperature hardness and heat resistance. For this reason, a low friction coefficient is maintained even under high temperature cutting conditions, and excellent heat resistance is exhibited, but the a value (atomic ratio, the same applies hereinafter) indicating the Cr content in the total amount with Al is 0. If it is less than .25, high temperature strength cannot be secured, and abnormal damage is caused at the boundary portion of the cutting edge and defects are likely to occur, so a long life cannot be expected. When the a value indicating the Cr content ratio exceeds 0.55, the Al content ratio is relatively decreased, and not only the high-temperature hardness required for high-speed cutting can be secured, but also wear resistance. The a value was determined to be 0.25 to 0.55 because the property also deteriorated and it was difficult to prevent the occurrence of chipping.
The b (atomic ratio) indicating the content ratio of N in the total amount of O and N is the content ratio of the component N essential for increasing the hardness of the (Al, Cr) (ON) layer. In order to make the effect sufficient, it is necessary to occupy more than half of the total amount of O and N. However, if b exceeds 0.95, the content ratio of O is relatively less than 0.05, and the effect of improving heat resistance by the addition of O is not sufficiently achieved. Therefore, the a value was set to 0.50 to 0.95.

(C) Composition of (Al, Mn) (ON) layer constituting thin layer B layer:
The (Al _1-c Mn _c ) (O _1-d N _d ) layer of the thin layer B that constitutes an alternate laminated structure with the thin layer A described above has uniform wear resistance, heat resistance and toughness throughout the layer. However, the Mn component, which is a constituent component, provides excellent high-temperature stability, and by using a composite oxynitride of Al and Mn, wear resistance is improved compared to each oxide. To do. As a result, high temperature hardness and heat resistance are complemented by cutting components. Therefore, a low friction coefficient is maintained even under high temperature cutting conditions, and excellent heat resistance is exhibited. However, the c value (atomic ratio, the same applies hereinafter) indicating the content ratio of Mn in the total amount with Al is 0. If it is less than 10.10, high temperature strength cannot be ensured, so abnormal damage is caused at the boundary portion of the blade edge and defect is likely to occur, so a long life cannot be expected. When the c value indicating the Mn content ratio exceeds 0.50, the Al content ratio is relatively reduced, and not only the high-temperature hardness required for high-speed cutting cannot be secured, but also wear resistance. The c value was determined to be 0.10 to 0.50 because it was difficult to prevent the occurrence of chipping.
1-d (atomic ratio) indicating the content ratio of O in the total amount of O and N is the content ratio of the component O essential for improving the heat resistance of the (Al, Mn) (ON) layer. In order to make the effect sufficient, it is necessary to occupy more than half of the total amount of O and N. However, when 1-d exceeds 0.99, the content ratio of N is relatively less than 0.01, and the effect of improving the hardness due to the addition of N is not sufficiently achieved. Therefore, d value was defined as 0.01 or more and 0.50 or less.

(D) Average layer thickness of thin layer A and thin layer B and total layer thickness of hard coating layer:
The hard coating layer of the present invention has an alternate laminated structure in which thin layers A and thin layers B having different compositions are alternately laminated, thereby preventing the growth of particles in each layer from being coarsened. The particle size is reduced, the film strength is improved, and crack propagation and progress are prevented by this laminated structure, thereby improving the chipping resistance and chipping resistance. Is less than 0.1 μm and the average layer thickness of the thin layer B is less than 0.05 μm, it is difficult to clearly form each thin layer as having a predetermined composition. Unable to demonstrate the characteristics. On the other hand, if the average layer thickness of the thin layer A exceeds 1.0 μm and the average layer thickness of the thin layer B exceeds 0.5 μm, the chip strength and chipping resistance decrease due to the decrease in film strength due to the coarsening of the particles. Therefore, the average layer thickness of each of the thin layer A and the thin layer B was determined to be 0.1 to 1.0 μm and 0.05 to 0.5 μm.
In addition, if the total thickness of the hard coating layer including the above-described underlayer and the alternately laminated structure of the thin layers A and B is less than 1.0 μm, the excellent defect resistance provided by the above-mentioned alternately laminated structure is less than 1.0 μm. On the other hand, when the thickness exceeds 10.0 μm, chipping and defects tend to occur, so that the total thickness of the hard coating layer is 1.0 to It was determined to be 10.0 μm.
Furthermore, when the layer thickness (X) of the underlayer is thinner than the total layer thickness (Y) of the alternately laminated thin layers A and B formed thereon, the ratio of the hard film to the total thickness is relative Since the wear resistance cannot be sufficiently secured, the relationship between the layer thickness (X) of the underlayer and the total layer thickness (Y) of the alternate lamination of the thin layers A and B is X> Y was determined.

The (Al, Cr) N layer constituting the base layer constituting the hard coating layer of the present invention shown in FIG. 3, the (Al, Cr) (ON) layer constituting the thin layer A, and the thin layer B are constituted. The (Al, Mn) (ON) layer to be used is, for example, a tool base is loaded into an arc ion plating apparatus which is one type of physical vapor deposition apparatus shown in the schematic explanatory diagram of FIG. For example, in a state heated to a temperature of 500 ° C.
(A) For example, an arc discharge is generated between the anode electrode and the Al—Cr alloy as the cathode electrode (evaporation source) under the condition of current: 110 A, and at the same time, nitrogen gas is introduced into the apparatus as a reaction gas. For example, the reaction atmosphere is 5.0 Pa, and the tool base is a base layer having a predetermined target layer thickness on the tool base surface by vapor deposition for a predetermined time, for example, under the condition that a bias voltage of −70 V is applied. An (Al, Cr) N layer is formed.
(B) For example, an arc discharge is generated between the anode electrode and the Al—Cr alloy as the cathode electrode (evaporation source) under the condition of current: 110 A, and at the same time, the atmosphere in the apparatus is 0.5 to 9.0 Pa. An oxygen-nitrogen mixed atmosphere (for example, an oxygen: nitrogen flow rate ratio of 50:50) is deposited on the tool base surface for a predetermined time under a condition where, for example, a bias voltage of −100 V is applied. Then, the (Al, Cr) (ON) layer that is the thin layer A having a predetermined target layer thickness is formed.
(C) Next, a cathode electrode (evaporation source) made of an Al—Mn alloy having a predetermined composition is disposed in the apparatus, and, for example, an electric current is provided between the anode electrode and the Al—Mn alloy as the cathode electrode (evaporation source). : Arc discharge is generated under the condition of 110A, and the atmosphere in the apparatus is set to an oxygen-nitrogen mixed atmosphere of 0.5 to 9.0 Pa (for example, the ratio of oxygen: nitrogen flow% is 50:50). For example, an (Al, Mn) (ON) layer constituting a thin layer B having a predetermined target layer thickness is formed on the thin layer A by performing deposition for a predetermined time under the condition that a bias voltage of −100 V is applied. It is formed.
By repeating the steps (b) and (c) until a predetermined total layer thickness is obtained, the hard coating layer of the present invention can be formed by vapor deposition.

  According to one aspect of the coated tool of the present invention, a thin layer A composed of an (Al, Cr) (ON) layer and an (Al, Mn) layer on an underlayer composed of an (Al, Cr) N layer as a hard coating layer. By having an alternately laminated structure with the thin layer B composed of the (ON) layer, the excellent wear resistance and heat resistance exhibited by the thin layer A, and the excellent high temperature hardness and heat resistance exhibited by the thin layer B, Due to the synergistic effect with toughness, the hard coating layer has excellent high temperature hardness, heat resistance, high temperature strength, wear resistance, lubricity, impact resistance, chipping resistance, chipping resistance. In particular, high wear resistance and heat resistance are exhibited over a long period of time even when high-speed cutting is performed with a large load accompanied by large heat generation such as a titanium alloy, a heat-resistant alloy, and stainless steel.

The arc ion plating apparatus used for forming the hard coating layer which comprises this invention coated tool and a comparative 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 explaining a prior art. It is a longitudinal cross-sectional film | membrane structural view of the hard coating layer which comprises this invention coated tool.

  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 into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C. for 1 hour, and after sintering, tool bases A-1 to A-6 made of WC-base cemented carbide having an ISO standard / CNMG120408 insert 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, this 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 substrate B made of TiCN base cermet having an ISO standard / CNMG120408 insert shape was used. -1 to B-4 were formed.

(A) Next, each of the tool bases A-1 to A-6 and B-1 to B-4 is ultrasonically cleaned in acetone and dried, and then the arc ion plating apparatus shown in FIG. A first electrode is provided with two cathode electrodes (evaporation sources) that are mounted along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the inner rotary table, and that face each other across the rotary table. An Al—Cr alloy having a predetermined composition for forming the underlayer and the thin layer A, and an Al—Mn alloy having a predetermined composition for forming the thin layer B as the second electrode,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then rotated to a tool base that rotates while rotating on a rotary table. A DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the Al—Cr alloy (cathode electrode) and the anode electrode, and the tool base surface is bombard washed.
(C) Next, the atmosphere in the apparatus is maintained in a nitrogen atmosphere of 0.5 to 9.0 Pa, and a DC bias voltage of -20 to -150 V is applied to the rotating tool base while rotating on the rotary table, and the cathode An arc discharge is generated by flowing a current of 120 A between an Al—Cr alloy electrode, which is an electrode (evaporation source), and an anode electrode, and (Al) as an underlayer having a target composition and a target layer thickness shown in Table 3 , Cr) N layer was deposited.
(D) Next, the atmosphere in the apparatus is maintained in an oxygen-nitrogen mixed atmosphere of 0.5 to 9.0 Pa (for example, the ratio of the flow rate% of oxygen: nitrogen is 50:50), and rotates while rotating on the rotary table. A DC bias voltage of −20 to −150 V was applied to the tool base, and a current of 120 A was passed between the Al—Cr alloy electrode as the cathode electrode (evaporation source) and the anode electrode to generate arc discharge. The (Al, Cr) (ON) layer as the thin layer A having the target composition and target layer thickness shown in FIG.
(E) Next, the atmosphere inside the apparatus is maintained in an oxygen-nitrogen mixed atmosphere of 0.5 to 9.0 Pa (for example, the ratio of the flow rate% of oxygen: nitrogen is 50:50), and rotates while rotating on the rotary table. A direct current bias voltage of −50 to −150 V is applied to the tool base, and a current of 120 A is passed between the Al—Mn alloy of the cathode electrode and the anode electrode to generate an arc discharge. On top of this, after the (Al, Mn) (ON) layer as the thin layer B having the target composition and target layer thickness shown in Table 3 is formed by vapor deposition, arc discharge between the cathode electrode (evaporation source) and the anode electrode is performed. Stop
By alternately repeating the steps (d) and (e), an alternate lamination having a total layer thickness shown in Table 3 is formed on the underlayer on the tool substrate by vapor deposition. (Referred to as a coated insert of the present invention) 1 to 10 were produced.

For comparison purposes,
(A) Each of the tool bases A-1 to A-6 and B-1 to B-4 is ultrasonically cleaned in acetone and dried, and then in the arc ion plating apparatus shown in FIG. Attached along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table, two cathode electrodes (evaporation sources) facing each other across the rotary table are arranged, and the first electrode is An Al—Cr alloy having a predetermined composition for forming the thin layer A and an Al—Mn alloy having a predetermined composition for forming the thin layer B as the second electrode are disposed,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then rotated to a tool base that rotates while rotating on a rotary table. A DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the Al—Cr alloy (cathode electrode) and the anode electrode, and the tool base surface is bombard washed.
(C) Next, the atmosphere in the apparatus is maintained in a nitrogen atmosphere of 0.5 to 9.0 Pa, and a DC bias voltage of -20 to -150 V is applied to the rotating tool base while rotating on the rotary table, and the cathode An arc discharge is generated by passing a current of 120 A between the Al—Cr alloy electrode, which is an electrode (evaporation source), and the anode electrode, and (Al) as an underlayer having a target composition and a target layer thickness shown in Table 4 , Cr) N layer was deposited.
(D) Next, the atmosphere in the apparatus is maintained in an oxygen-nitrogen mixed atmosphere of 0.5 to 9.0 Pa (for example, the oxygen: nitrogen flow rate ratio is 90:10), and rotates while rotating on the rotary table. A DC bias voltage of −20 to −150 V is applied to the tool base, and a current of 120 A is passed between the Al—Cr alloy electrode, which is the cathode electrode (evaporation source), and the anode electrode to generate arc discharge. The (Al, Cr) (ON) layer as the thin layer A having the target composition and target layer thickness shown in Table 4 was formed by vapor deposition.
(E) Subsequently, the atmosphere in the apparatus is maintained in an oxygen-nitrogen mixed atmosphere of 0.5 to 9.0 Pa (for example, the ratio of the flow rate% of oxygen: nitrogen is 5:95) and rotates while rotating on the rotary table. A DC bias voltage of −20 to −500 V is applied to the tool base to be used, and a current of 120 A is passed between the Al—Mn alloy of the cathode electrode and the anode electrode to generate an arc discharge. Further, after the (Al, Mn) (ON) layer as the thin layer B having the target composition and the target layer thickness shown in Table 4 is formed by vapor deposition, arc discharge between the cathode electrode (evaporation source) and the anode electrode is performed. Stop,
By alternately repeating the steps (d) and (e), an alternate lamination having a total layer thickness shown in Table 4 is formed on the underlayer by vapor deposition, and a surface coating insert (hereinafter referred to as a comparative coating insert) is used as a comparative coating tool. 1) to 6 were produced. The formation conditions (bias voltage, oxygen partial pressure, nitrogen partial pressure) of each layer are also shown in Table 4. In addition, about the comparison covering insert 1, it did not form alternate lamination | stacking, but was taken as the hard coating layer which consists only of an (Al, Cr) N layer.

About this invention coated insert 1-10 and comparative coated inserts 1-4, the cutting test was done on the following cutting conditions.
Work Material: Ni-19% Cr-18.5% Fe-5.2% Cd-5% Ta-3% Mo-0.9% Ti-0.5% Al-0.3% by mass% Ni-based alloy round bar having a composition of Si-0.2% Mn-0.05% Cu-0.04% C;
Cutting speed: 55 m / min. ,
Cutting depth: 2.0 mm,
Feed: 0.20 mm / rev. ,
Cutting time: 6 minutes,
Wet continuous high-speed high-feed cutting test of Ni-based alloy under the following conditions (cutting condition A) (normal cutting speed and feed are 35 m / min. And 0.15 mm / rev., Respectively),
Work material: JIS / SUS304 (HB180) round bar,
Cutting speed: 145 m / min. ,
Cutting depth: 2.5mm,
Feed: 0.3 mm / rev. ,
Cutting time: 9 minutes,
(Continuous cutting speed and feed rate are 120 m / min. And 0.3 mm / rev., Respectively)
Work material: Round bar of Ti base alloy having a composition of Ti-6% Al-4% V in mass%,
Cutting speed: 115 m / min. ,
Cutting depth: 2.5 mm,
Feed: 0.25 mm / rev. ,
Cutting time: 11 minutes,
Wet continuous high-speed high-cut cutting test of Ti-based alloy under the following conditions (cutting condition C) (normal cutting speed, cutting and feed are 100 m / min., 2.0 mm., 0.2 respectively. mm / rev.),
The flank wear width of the cutting edge was measured in any high-speed cutting test. The measurement results are shown in Tables 5 and 6.

As in Example 1, all of WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder having an average particle diameter of 1 to 3 μm. The raw material powder consisting of the above is blended in the composition shown in Table 1, wet mixed for 72 hours with a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa. , Temperature: Sintered at 1400 ° C. for 1 hour to form a round tool sintered body for forming a tool base having a diameter of 13 mm. WC-base cemented carbide tool bases (end mills) A-1 to A-6 having a four-blade square shape with a diameter x length of 10 mm x 22 mm and a twist angle of 30 degrees were manufactured. .

  Then, the surfaces of these tool bases (end mills) A-1 to A-6 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. 1 under the same conditions as in Table 1, the target composition shown in Table 7 and the target layer thickness (Al, Cr) N layer, and the target composition shown in Table 7 and target layer thickness (Al, Mn) ( ON) Layers composed of (Al, Cr) (ON) layers with target composition and target layer thicknesses shown in Table 7 and alternating layers of thin layers B (Al, Mn) (ON) layers By forming a hard coating layer having a target total layer thickness shown in Table 7 having a structure by vapor deposition, the surface coated carbide end mill (hereinafter referred to as the present coated end mill) 1 to 10 as the coated tool of the present invention. Were manufactured respectively.

For comparison purposes, the surfaces of the tool bases (end mills) A-1 to A-5 are ultrasonically cleaned in acetone and dried, and then loaded into the arc ion plating apparatus shown in FIG. Then, in the same process as in Example 1, using the formation conditions (bias voltage, nitrogen partial pressure) shown in Table 8, the target composition and target layer thickness (Al, Cr) N layers shown in Table 8 are used. Alternating layered structure of underlayer and thin layer A composed of (Al, Cr) (ON) layer having the target composition and thickness shown in Table 8 and thin layer B composed of (Al, Mn) (ON) layer Surface-coated cemented carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 5 as comparative coated tools were produced by vapor-depositing and forming a hard coated layer having a target total layer thickness shown in Table 8 below. In addition, about the comparison coating | coated end mill 1, the formation of an alternating lamination was not performed but it was set as the hard coating layer of only the (Al, Cr) N layer.
Next, for the present invention coated end mills 1-10 and comparative coated end mills 1-5,
Work Material-Plane Dimensions: 100mm x 250mm, Thickness: 50mm, Mass%, Ni-19% Cr-14% Co-4.5% Mo-2.5% Ti-2% Fe-1.2 Ni-base alloy plate material having a composition of% Al-0.7% Mn-0.4% Si,
Cutting speed: 60 m / min. ,
Groove depth (cut): 2 mm,
Table feed: 135mm / min,
Wet high-speed grooving test of Ni-based alloy under the following conditions (normal cutting speed and groove depth are 50 m / min. And 1.0 mm, respectively),
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 7 and 8, respectively.

  The round bar sintered body with a diameter of 13 mm manufactured in Example 2 was used, and from this round bar sintered body, the dimensions of the groove forming part diameter × length were 8 mm × 22 mm and the twist angle by grinding. WC base cemented carbide tool bases (drills) A-1 to A-6 each having a 30-degree two-blade shape were produced.

  Next, the cutting blades of these tool bases (drills) A-1 to A-6 are subjected to honing, ultrasonically cleaned in acetone, and dried in the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, the base composition composed of (Al, Cr) N layers with the target composition and target layer thickness shown in Table 9, and the target composition and target layer thickness shown in Table 9 It is composed of an alternating laminated structure of a thin layer A composed of (Al, Cr) (ON) layers and a thin layer B composed of (Al, Mn) (ON) layers having the target composition and target layer thickness also shown in Table 9. Similarly, by forming a hard coating layer having a target total layer thickness shown in Table 9 by vapor deposition, the surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 10 as the present invention-coated tools are respectively provided. Manufactured.

  For the purpose of comparison, the surfaces of the tool bases (drills) A-1, 2, 4 to 6 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc shown in FIG. The ion plating apparatus was charged, and in the same process as in Example 1, using the formation conditions (bias voltage, nitrogen partial pressure) shown in Table 10, the target composition and target layer thickness (Al , Cr) N layer, a target composition shown in Table 10 and a thin layer A consisting of an (Al, Cr) (ON) layer with a target layer thickness, and a target composition and target layer thickness shown in Table 10. Surface coating as a comparative coating tool by vapor-depositing a hard coating layer having a target total layer thickness shown in Table 10 consisting of an alternately laminated structure with thin layers B consisting of (Al, Mn) (ON) layers. Hard drills (hereinafter referred to as comparative coated drills) 1 to 5 Each was produced. In addition, about the comparison covering drill 1, the formation of an alternating lamination was not performed but it was set as the hard coating layer only of the (Al, Cr) N layer.

Next, for the present invention coated drills 1-10 and comparative coated drills 1-5,
Work Material—Plane Size: 100 mm × 250 mm, Thickness: 50 mm, Mass%, Ni-19% Cr-18.5% Fe-5.2% Cd-5% Ta-3% Mo-0.9 Ni-based alloy plate having a composition of% Ti-0.5% Al-0.3% Si-0.2% Mn-0.05% Cu-0.04% C,
Cutting speed: 60 m / min. ,
Feed: 0.20 mm / rev,
Hole depth: 25 mm,
Wet high-speed drilling machining test of Ni-based alloy under the conditions (normal cutting speed and feed are 20 m / min. And 0.12 mm / rev, respectively),
(Using water-soluble cutting oil), and the number of drilling operations was measured until the flank wear width of the cutting edge surface reached 0.3 mm. The measurement results are shown in Tables 9 and 10, respectively.

  It is a thin layer A constituting the hard coating layer of the present coated inserts 1 to 10, the present coated end mills 1 to 10, and the present coated drills 1 to 10 as the present coated tool obtained as a result (Al, Cr) (ON) layer and thin layer B (Al, Mn) (ON) layer composition, comparative coated inserts 1-6 as comparative coated tools, comparative coated end mills 1-5, and comparative coated drill 1 The composition of the (Al, Cr) (ON) layer that is the thin layer A and the (Al, Mn) (ON) layer that is the thin layer B and the base layer (Al, Cr) When the composition of the N layer was measured by energy dispersive X-ray analysis using a transmission electron microscope, it showed substantially the same composition as the target composition.

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

  From the results shown in Tables 3 to 10, the coated tool of the present invention formed an underlayer having a predetermined composition and target layer thickness on the tool base, and then a thin layer A having a predetermined composition and target layer thickness, and a predetermined layer. As a result of forming an alternate laminate composed of a thin layer B having a composition of the target layer thickness and a thin layer A, the (Al, Cr) (ON) layer, which is the thin layer A, is in a state of being firmly bonded to the tool base surface. The thin layer A and the thin layer B have different heat resistance and wear resistance, and the (Al, Mn) (ON) layer, which is the thin layer B, has improved properties, high temperature hardness, and high temperature strength. As a result of improving the impact resistance, chipping resistance, and crack progress resistance by the synergistic effect of alternating lamination, excellent chipping resistance is ensured even during high-speed cutting of titanium alloys, heat-resistant alloys, stainless steel, etc. No wear and excellent wear resistance over a long period of time To. On the other hand, in the comparative coated tool in which any one of the layers constituting the hard coating layer deviates from the composition and average layer thickness specified in the present invention, all are high-speed cutting of titanium alloy, heat-resistant alloy, and stainless steel. It is apparent that the wear resistance is not sufficient and the toughness of the film is reduced, so that 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 is excellent in wear resistance and fracture resistance in high-speed cutting such as titanium alloy, heat-resistant alloy, stainless steel as well as cutting of general work materials. Since it exhibits excellent cutting performance and exhibits excellent cutting performance over a long period of time, it can satisfactorily respond to automation of the cutting apparatus, labor saving and energy saving of cutting, and cost reduction.

Claims (1)

In a surface-coated cutting tool formed by forming a hard coating layer on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.55 to 5.5 μm formed on the surface of the tool substrate; and
Composition formula: (Al _1-e Cr _e ) N (where e represents the content ratio of Cr in the total amount of Al and Cr, and the atomic ratio is 0.25 ≦ e ≦ 0.55) A satisfactory underlayer,
(B) having an average layer thickness of 0.1 to 1.0 μm, and
Composition formula: (Al _1-a Cr _a ) (O _1-b N _b ) (where a represents the content ratio of Cr in the total amount of Al and Cr, and the atomic ratio is 0.25 ≦ a ≦ In addition, b represents the content ratio of N in the total amount of O and N, and the composite nitridation of Al and Ti satisfying the atomic ratio of 0.50 ≦ b ≦ 0.95) A thin layer A composed of physical layers;
(C) having an average layer thickness of 0.05 to 0.5 μm, and
Composition formula: (Al _1-c Mn _c ) (O _1-d N _d ) (where c represents the content ratio of Mn in the total amount of Al and Mn, and the atomic ratio is 0.10 ≦ c ≦ In addition, d represents the content ratio of N in the total amount of O and N, and the composite nitridation of Al and Mn satisfying the atomic ratio of 0.01 ≦ d ≦ 0.50) A thin layer B composed of physical layers,
The thin layer A and the thin layer B are alternately laminated on the foundation layer, and the layer thickness of the foundation layer is thicker than the total layer thickness of the alternate lamination formed on the upper layer. Is a surface-coated cutting tool characterized in that it is thicker than the layer thickness of the thin layer B, and the total layer thickness of the entire hard coating layer is 1.0 to 10.0 μm.