JP4621975B2 - Surface-coated cemented carbide cutting tool with excellent wear resistance due to high-speed cutting and hard coating layer - Google Patents

Description

  In the present invention, the hard coating layer is constituted by a lower layer having excellent high-temperature hardness and heat resistance and an upper layer having excellent high-temperature oxidation resistance, and therefore various Ti-based alloys and high Si-containing Al- Even when cutting hard hard-to-cut materials such as Si-based alloys under high-speed cutting conditions with high heat generation, a surface-coated cemented carbide cutting tool that exhibits excellent wear resistance over a long period of time (hereinafter referred to as the following) This is related to a coated carbide tool.

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

Further, as a coated carbide tool, on the surface of a carbide substrate composed of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet,
Composition formula: (Ti _1-X Al _X ) N (however, in atomic ratio, X represents 0.40 to 0.75),
There is known a coated carbide tool formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Ti and Al satisfying the following conditions (hereinafter referred to as (Ti, Al) N) with an average layer thickness of 1 to 10 μm. Since the (Ti, Al) N layer has high-temperature hardness and heat resistance due to Al as a constituent component and high-temperature strength due to the Ti, the coated carbide tool is continuously cut from various steels and cast irons. It is also known to exhibit excellent cutting performance when used for intermittent cutting.

Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, in a state heated to a temperature of 500 ° C., an arc discharge is generated between the anode electrode and the cathode electrode (evaporation source) in which a Ti—Al alloy having a predetermined composition is set, for example, under a current of 90 A, At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to give a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate is applied with a bias voltage of, for example, −100 V on the surface of the carbide substrate. It is also known that it is produced by vapor-depositing a hard coating layer composed of a (Ti, Al) N layer.
Japanese Patent No. 2644710

  The performance and automation of cutting machines in recent years have been remarkable. On the other hand, there are strong demands for labor saving and energy saving and further cost reduction for cutting. Accordingly, cutting speed has been increased and types of work materials have been increased. Although there is a tendency that a general-purpose coated carbide tool not limited to the above is widely desired, in the above-mentioned conventional coated carbide tool, this is performed on various cutting materials such as steel and cast iron under normal cutting conditions. There is no problem when it is used for, but when this is used to perform cutting of hard difficult-to-cut materials such as various Ti-based alloys and high Si-containing Al-Si based alloys under high-speed cutting conditions, The extremely high heat generated at the time of cutting significantly accelerates the progress of wear of the hard coating layer, so that the service life is reached in a relatively short time.

In view of the above, the present inventors have developed the above-described coated carbide tool that exhibits excellent wear resistance in which the hard coating layer is excellent in high-speed cutting of the hard difficult-to-cut materials. As a result of conducting research focusing on conventional coated carbide tools,
(A) When a (Ti, Al) N layer, which is a hard coating layer of the above conventional coated carbide tool, is used as a lower layer, and a chromium boride (hereinafter referred to as CrB ₂ ) layer is formed thereon as an upper layer, Since the CrB ₂ layer has excellent high-temperature oxidation resistance, the lower layer (Ti, Al) N is formed from a heated atmosphere caused by high heat generated during high-speed cutting of the hard hard-to-cut material, which is a work material. The layer is well protected, and as a result, the excellent properties of the (Ti, Al) N layer can be fully exerted over a long period of time.

(B) However, the adhesion between the CrB ₂ layer as the upper layer and the (Ti, Al) N layer as the lower layer was particularly high-speed cutting of the hard difficult-to-cut material in an intermittent cutting mode. In some cases, peeling phenomenon is likely to occur, and it cannot be said that it is sufficient. However, when a chromium nitride (hereinafter referred to as CrN) layer is interposed between the CrB ₂ layer and the (Ti, Al) N layer, Since the CrN layer firmly adheres to both the CrB ₂ layer and the (Ti, Al) N layer, the (Ti, Al) N layer has excellent adhesion to the surface of the carbide substrate; In combination, the hard coating layer formed by interposing the CrN layer between the CrB ₂ layer and the (Ti, Al) N layer is capable of high-speed cutting of the hard difficult-to-cut material with high heat generation. Demonstrate excellent wear resistance without delamination.

(C) The hard coating layer of (b) is, for example, an arc ion plating apparatus (hereinafter, abbreviated as AIP apparatus) having a structure shown in a schematic plan view in FIG. 1 (a) and a schematic front view in (b). And a sputtering apparatus (hereinafter abbreviated as SP apparatus), that is, a carbide substrate mounting rotary table is provided at the center of the apparatus, and the cathode of the AIP apparatus is placed on one side of the rotary table. A metal Cr as an electrode (evaporation source) and a sintered body of Cr boride (hereinafter referred to as CrB ₂ ) as a cathode electrode (evaporation source) of the SP device on the other side (hereinafter referred to as a CrB ₂ sintered body) opposite arrangement, further along the rotary table, and a predetermined composition as a cathode electrode (vapor source) of the AIP device in a position 90 degrees apart from each of the metal Cr and CrB ₂ sintered body Using a vapor deposition apparatus in which a Ti-Al alloy is disposed, and mounting a plurality of cemented carbide substrates in a ring shape along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus, In this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the carbide substrate itself is rotated for the purpose of uniforming the thickness of the wear-resistant hard layer formed by vapor deposition. An arc discharge is generated between the cathode electrode (evaporation source) of the Ti—Al alloy and the anode electrode, and a (Ti, Al) N layer is formed on the surface of the carbide substrate with an average layer thickness of 0.8 to 5 μm. The lower layer is deposited and then the arc discharge between the Ti—Al alloy cathode electrode (evaporation source) and the anode electrode is stopped, and the metal Cr and anode serving as the cathode electrode (evaporation source) of the AIP device Electric After generating an arc discharge between the electrodes and depositing a CrN layer as an adhesion bonding layer with an average layer thickness of 0.1 to 0.5 μm, the atmosphere in the deposition apparatus is replaced with a nitrogen atmosphere, Although the mixed gas atmosphere of Ar and nitrogen is used, the Ar introduction rate is gradually increased over time, while the nitrogen introduction rate is gradually reduced. Simultaneously with the introduction of the mixed gas of Ar and nitrogen, sputtering of the CrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP apparatus was started, and after a predetermined time had elapsed after the start of sputtering, the metal Cr and anode electrode The arc discharge is stopped, and the CrB ₂ sintered body is sputtered for a predetermined time, and is deposited on the CrN layer to deposit a CrB ₂ layer with an average layer thickness of 0.8 to 5 μm as an upper layer. Can be formed.

(D) A coated carbide tool formed by vapor-depositing a hard coating layer composed of the lower layer, the adhesive bonding layer, and the upper layer is a variety of Ti-based alloys and high Si alloys that generate particularly high heat. In high-speed cutting of hard difficult-to-cut materials such as Al-Si alloys, the lower layer (Ti, Al) N layer has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength. The upper layer composed of the CrB ₂ layer, which is firmly adhered by the CrN layer as the bonding layer and has excellent high temperature oxidation resistance, is protected from the high temperature oxidation atmosphere at the time of cutting, and the atmospheric oxidation that causes wear promotion is remarkable. Since it is suppressed, it exhibits excellent wear resistance over a long period of time without delamination.
The research results shown in (a) to (d) above were obtained.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) having an average layer thickness of 0.8 to 5 μm and a composition formula: (Ti _1-X Al _X ) N (wherein X is 0.40 to 0.75 in terms of atomic ratio) A lower layer consisting of a satisfactory (Ti, Al) N layer,
(B) an adhesive bonding layer comprising a CrN layer having an average layer thickness of 0.1 to 0.5 μm;
(C) an upper layer composed of _two CrB layers having an average layer thickness of 0.8 to 5 μm,
The present invention is characterized by a coated cemented carbide tool which is formed by physical vapor deposition of the hard coating layer composed of the above (a) to (c) and exhibits excellent wear resistance by high-speed cutting.

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

(A) X value of the composition formula of the lower layer The Al component in the (Ti, Al) N layer constituting the lower layer improves the high temperature hardness and heat resistance, while the Ti component improves the high temperature strength. However, when the X value indicating the proportion of Al is less than 0.40 in terms of the total amount with Ti (atomic ratio, the same shall apply hereinafter), the proportion of Ti will be relatively large, and high-speed cutting will occur. The required high temperature hardness and heat resistance cannot be ensured, and the progress of wear is accelerated rapidly. On the other hand, if the X value indicating the proportion of Al exceeds 0.75, relatively Ti The ratio of the amount becomes too small, and the high-temperature strength rapidly decreases. As a result, chipping (small chipping) is likely to occur at the cutting edge, and the progress of wear is rapidly accelerated. It was set to 0.40 to 0.75.
Further, if the average layer thickness is less than 0.8 μm, it is insufficient to exhibit its excellent wear resistance over a long period of time. Since the chipping tends to occur at the cutting edge portion in high-speed cutting of the work material, the average layer thickness is set to 0.8 to 5 μm.

(B) Average layer thickness of the adhesive bonding layer If the average layer thickness is less than 0.1 μm, a strong bonding strength cannot be ensured between the upper layer and the lower layer, while the average layer thickness is 0.5 μm. If it exceeds 1, the strength of the hard coating layer suddenly decreases in the tight bonding layer portion, which causes chipping, so the average layer thickness was determined to be 0.1 to 0.5 μm.

(C) the average layer thickness hard layer of the top layer, the coexistence of the high-temperature hardness and heat resistance which is superior with street lower layer described above, and have excellent high-temperature oxidation resistance of CrB ₂ layer which is the upper layer , Which exhibits excellent wear resistance in high-speed cutting of hard difficult-to-cut materials with high heat generation, the average layer thickness of the CrB ₂ layer is less than 0.8 μm, It is insufficient to protect from the high-temperature oxidizing atmosphere at the time of cutting to the end of its service life. On the other hand, if the average layer thickness exceeds 5 μm, chipping tends to occur at the cutting edge portion. .8-5 μm.

In the coated carbide tool of the present invention, the (Ti, Al) N layer which is the lower layer of the hard coating layer has excellent high temperature hardness and heat resistance, and the lower layer is provided with a CrN layer as an adhesive bonding layer. The CrB ₂ layer, which is the upper layer that is tightly bonded tightly, has excellent high-temperature oxidation resistance, and the CrB ₂ layer protects the (Ti, Al) N layer well from the high-temperature oxidizing atmosphere during cutting. Demonstrates excellent wear resistance over a long period of time without delamination even during high-speed cutting of hard-to-cut materials such as various Ti-based alloys and high Si-containing Al-Si-based alloys that generate particularly high heat. To do.

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

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

In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. TiCN-based cemented carbide substrates B-1 to B-6 having the following chip shape were formed.
Furthermore, as a cathode electrode (evaporation source) for forming the upper layer of the hard coating layer, CrB ₂ powder having an average particle diameter of 0.8 μm was hot pressed under the conditions of temperature: 1500 ° C., pressure: 20 MPa, holding time: 3 hours. Then, a CrB ₂ sintered body formed by molding was prepared.

(A) Next, each of the above-mentioned carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then in the vapor deposition apparatus shown in FIG. Attached along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table, a close contact bonding layer forming metal Cr as the cathode electrode (evaporation source) of the AIP device on one side, and the SP on the other side As a cathode electrode (evaporation source) of the apparatus, a CrB ₂ sintered body for forming an upper layer is disposed oppositely, and further along the rotary table and at a position 90 degrees away from each of the metal Cr and CrB ₂ sintered bodies. A Ti—Al alloy for forming a lower layer having a predetermined composition is disposed as a cathode electrode (evaporation source) of the AIP device,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, the interior of the apparatus is heated to 500 ° C. with a heater, and then rotated to a carbide substrate that rotates while rotating on the rotary table. A DC bias voltage is applied, and a current of 100 A is passed between the Ti-Al alloy and the anode electrode of the cathode electrode to generate an arc discharge, whereby the carbide substrate surface is bombarded with the Ti-Al alloy. And
(C) Nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, a DC bias voltage of −100 V is applied to a carbide substrate rotating while rotating on the rotary table, and a cathode electrode An arc discharge is generated by passing a current of 100 A between the Ti-Al alloy and the anode electrode, and the target composition and target layer thickness (Ti, Al) shown in Table 3 are formed on the surface of the carbide substrate. ) N layer is deposited as a lower layer of the hard coating layer,
(D) The arc discharge between the cathode electrode and the anode electrode of the Ti-Al alloy for forming the lower layer is stopped, the atmosphere in the apparatus is maintained in the same nitrogen atmosphere of 3 Pa, and direct current to the carbide substrate is maintained. While maintaining the same bias voltage (−100V), a current of 100 A is passed between the metal Cr of the cathode electrode and the anode electrode to generate an arc discharge, and thus a CrN layer having a target layer thickness similarly shown in Table 3 Is vapor-deposited as an adhesive bonding layer of a hard coating layer,
(E) While continuing the arc discharge between the metal Cr and the anode electrode, the atmosphere in the vapor deposition apparatus is changed to a mixed gas atmosphere of Ar and nitrogen instead of a nitrogen atmosphere. The ratio is gradually increased, while the nitrogen introduction ratio is gradually decreased, and finally the Ar atmosphere is obtained, and the reaction atmosphere is gradually decreased from 3 Pa to 0.3 Pa with time, and the vapor deposition apparatus. Simultaneously with the introduction of a mixed gas of Ar and nitrogen into the inside, sputtering was started on a CrB ₂ sintered body arranged as a cathode electrode (evaporation source) of the SP apparatus under the condition of sputtering output: 3 kW, and the metal Cr and anode electrode Arc discharge with the reaction atmosphere was stopped when the ratio of nitrogen in the mixed gas of Ar and nitrogen reached 10% by volume,
(F) After that, while maintaining the Ar atmosphere of 0.3 Pa, the sputtering was continued under the same conditions as the sputtering output of 3 kW between the CrB ₂ sintered body and the anode electrode. By depositing a CrB ₂ layer having a target layer thickness as an upper layer of the hard coating layer, the surface-coated carbide throw-away tip of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the present coated chip). 1 to 16 were produced.

  For the purpose of comparison, these carbide substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, in the vapor deposition apparatus shown in FIG. The Ti-Al alloy with various component compositions was attached as the cathode electrode (evaporation source). First, the inside of the apparatus was evacuated and kept at a vacuum of 0.1 Pa or less with the heater. After heating to 500 ° C., a DC bias voltage of −1000 V is applied to the cemented carbide substrate, and an arc discharge is generated by flowing a current of 100 A between the Ti—Al alloy of the cathode electrode and the anode electrode, Accordingly, the surface of the carbide substrate is bombarded with the Ti—Al alloy, and then nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, and a bias voltage applied to the carbide substrate is −100 V. And generating an arc discharge between the cathode electrode and the anode electrode of the Ti-Al alloy, and thus on the surfaces of the carbide substrates A-1 to A-10 and B-1 to B-6, A conventional surface-coated carbide throwaway tip (hereinafter referred to as a conventional coated carbide tool) as a conventionally coated carbide tool is formed by vapor deposition of a (Ti, Al) N layer having a target composition and a target layer thickness shown in Table 4 as a hard coating layer. (Referred to as coated chips) 1 to 16 were produced.

Next, in the state where each of the above-mentioned various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1-16 and the conventional coated chips 1-16,
Work material: Al-18% Si alloy round bar by mass%,
Cutting speed: 280 m / min. ,
Incision: 1.5mm,
Feed: 0.25 mm / rev. ,
Cutting time: 10 minutes,
Dry-type continuous high-speed cutting test of a high Si content Al—Si based alloy under the conditions of (normal cutting speed is 180 m / min.),
Work material: Ti-6% Al-4% V alloy round bar,
Cutting speed: 85 m / min. ,
Incision: 1.5mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes
Dry continuous high-speed cutting test of Ti-based alloy under the conditions (normal cutting speed is 40 m / min.),
Work material: Mass%, Al-13% Si alloy lengthwise equidistant 4 round rods with flutes,
Cutting speed: 250 m / min. ,
Cutting depth: 1.2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 13 minutes
The dry interrupted high-speed cutting test (normal cutting speed was 150 m / min.) Of the high Si-containing Al—Si alloy under the conditions was performed, and the flank wear width of the cutting edge was measured in any of the cutting tests. The measurement results are shown in Table 5.

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 powders were prepared, each of these raw material powders was blended in the composition shown in Table 6, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then shaped 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 Three types of sintered carbide rod forming bodies for forming a carbide substrate having diameters of 8 mm, 13 mm, and 26 mm were formed, and further, the three types of round rod sintered bodies described above were subjected to grinding and shown in Table 7. 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 Carbide substrates (end mills) C-1 to C-8 were produced.

Subsequently, the surfaces of these carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the vapor deposition apparatus shown in FIG. Under the same conditions as those shown in Table 7, an adhesive layer composed of a CrN layer with a target composition and a target layer thickness shown in Table 7, a CrN layer with a target layer thickness shown in Table 7, and CrB By forming a hard coating layer composed of _two upper layers by vapor deposition, the present invention surface coated carbide end mill (hereinafter referred to as the present invention coated end mill) 1 to 8 as the present coated carbide tool is formed. Each was manufactured.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then loaded into the vapor deposition apparatus shown in FIG. Conventionally as a conventional coated carbide tool by vapor-depositing a hard coating layer comprising a (Ti, Al) N layer having the target composition and target layer thickness shown in Table 7 under the same conditions as in Example 1 above. Surface-coated carbide end mills (hereinafter referred to as conventional coated end mills) 1 to 8 were produced, respectively.

Next, of the present invention coated end mills 1 to 8 and the conventional coated end mills 1 to 8, the present coated end mills 1 to 3 and the conventional coated end mills 1 to 3 are as follows:
Work material-plane: 100 mm × 250 mm, thickness: 50 mm high Si content Al—Si alloy (mass%, Al-18% Si alloy) plate material,
Cutting speed: 260 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 800mm / min,
The dry high-speed grooving test (normal cutting speed is 150 m / min.) Of the high Si content Al—Si alloy under the conditions of the present invention, the coated end mills 4 to 6 and the conventional coated end mills 4 to 6 are as follows:
Work material-plane: 100 mm × 250 mm, thickness: 50 mm Ti-based alloy (mass%, Ti-3% Al-2.5% V alloy) plate material,
Cutting speed: 55 m / min. ,
Groove depth (cut): 3.5 mm,
Table feed: 250 mm / min,
With respect to the dry high-speed grooving test of a Ti-based alloy under the conditions (normal cutting speed is 30 m / min.), The present coated end mills 7 and 8 and the conventional coated end mills 7 and 8,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm Ti-based alloy (mass%, Ti-6% Al-4% V alloy) plate material,
Cutting speed: 50 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 160 mm / min,
A dry high-speed grooving test of a Ti-based alloy under normal conditions (normal cutting speed is 30 m / min.) Was performed, and the flank wear width of the outer peripheral edge of the cutting edge was the service life in any grooving test. The cutting groove length up to 0.1 mm, which is a guideline, was measured. The measurement results are shown in Table 7, respectively.

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

Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried, and then loaded into the vapor deposition apparatus shown in FIG. Then, under the same conditions as in Example 1, the lower layer consisting of the (Ti, Al) N layer having the target composition and target layer thickness shown in Table 8 and the CrN layer having the target layer thickness also shown in Table 8 are used. The surface-coated carbide drill of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the coated drill of the present invention) is formed by vapor-depositing a hard coated layer composed of an adhesive bonding layer and an upper layer composed of _two CrB layers. 1) -8 were produced respectively.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. Conventionally, a hard coating layer composed of a (Ti, Al) N layer having the target composition and target layer thickness shown in Table 8 is formed by vapor deposition under the same conditions as in Example 1 above. Conventional surface-coated carbide drills (hereinafter referred to as conventional coated drills) 1 to 8 as coated carbide tools were produced, respectively.

Next, of the present invention coated drills 1 to 8 and the conventional coated drills 1 to 8, the present invention coated drills 1 to 3 and the conventional coated drills 1 to 3 are:
Work material-plane: 100 mm × 250, thickness: 50 mm high Si content Al—Si based alloy (mass%, Al-18% Si alloy) plate material,
Cutting speed: 85 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 10mm,
Wet high-speed drilling test of a high Si content Al-Si alloy under the conditions (normal cutting speed is 30 m / min.), The present invention coated drills 4-6 and conventional coated drills 4-6,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm Ti-based alloy (mass%, Ti-3% Al-2.5% V alloy) plate material,
Cutting speed: 50 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 15mm,
With respect to the wet-type high-speed drilling test of the Ti-based alloy under the conditions (normal cutting speed is 30 m / min.), The present invention coated drills 7 and 8 and the conventional coated drills 7 and 8,
Work material-plane: 100 mm × 250 mm, thickness: plate material of Ti-based alloy (Ti-6% Al-4% V alloy in mass%) having dimensions of 50 mm,
Cutting speed: 55 m / min. ,
Feed: 0.3mm / rev,
Hole depth: 28mm,
The high-speed drilling machining test (normal cutting speed is 25 m / min.) Of the Ti-based alloy under the above conditions, and the tip cutting edge surface in any wet high-speed drilling machining test (using water-soluble cutting oil) The number of drilling processes until the flank wear width of 0.3 mm was measured. The measurement results are shown in Table 8, respectively.

この結果得られた本発明被覆超硬工具としての本発明被覆チップ１〜１６、本発明被覆エンドミル１〜８、および本発明被覆ドリル１〜８の硬質被覆層を構成する耐摩耗硬質層の組成、並びに比較被覆超硬工具としての従来被覆チップ１〜１６、従来被覆エンドミル１〜８、および従来被覆ドリル１〜８の硬質被覆層の耐摩耗硬質層の組成を、透過型電子顕微鏡を用いてのエネルギー分散Ｘ線分析法により測定したところ、それぞれ目標組成と実質的に同じ組成を示した。

The composition of the wear-resistant hard layer constituting the hard coating layer of the present coated chips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated carbide tool obtained as a result. The composition of the hard coating layer of the hard coating layer of the conventional coated tips 1 to 16, the conventional coated end mills 1 to 8 and the conventional coated drills 1 to 8 as a comparative coated carbide tool using a transmission electron microscope When measured by an energy dispersive X-ray analysis method, each showed substantially the same composition as the target composition.

  Moreover, when the average layer thickness of the constituent layers of the hard coating layer was measured by a cross-section using a scanning electron microscope, all showed an average value (average value of five locations) substantially the same as the target layer thickness.

From the results shown in Tables 3 to 8, the coated carbide tool of the present invention is accompanied by high heat generation even in high-speed cutting of hard difficult-to-cut materials such as various Ti-based alloys and high Si-containing Al-Si based alloys. Nevertheless, the (Ti, Al) N layer, which is the lower layer of the hard coating layer, has excellent high-temperature hardness and heat resistance, and further excellent high-temperature strength. Because it is firmly adhered by the CrN layer as a layer and protected by a CrB ₂ layer having excellent high-temperature oxidation resistance, it exhibits excellent wear resistance over a long period without delamination. On the other hand, in the conventional coated carbide tool consisting only of (Ti, Al) N layer, it is clear that high-speed cutting with high heat generation causes the wear of the cutting edge to progress rapidly and reach the service life in a relatively short time. It is.

  As described above, the coated carbide tool of the present invention is not only capable of cutting under normal cutting conditions such as various types of steel and cast iron, but also has a particularly high speed of the hard hard-to-cut materials with high heat generation. Because it exhibits excellent wear resistance even during cutting and exhibits excellent cutting performance over a long period of time, the cutting device has high performance and automation, cutting labor saving and energy saving, and low cost It is possible to cope with the conversion sufficiently satisfactorily.

The vapor deposition apparatus used for forming the surface coating layer which comprises a coated carbide tool is shown, (a) is a schematic plan view, (b) is a schematic front view. It is a schematic explanatory drawing of a normal arc ion plating apparatus.

Claims (1)

On the surface of the cemented carbide substrate composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) having an average layer thickness of 0.8 to 5 μm and a composition formula: (Ti _1-X Al _X ) N (wherein X is 0.40 to 0.75 in terms of atomic ratio) A lower layer consisting of a satisfactory nitride layer of Ti and Al,
(B) an adhesive bonding layer comprising a chromium nitride layer having an average layer thickness of 0.1 to 0.5 μm;
(C) an upper layer comprising a chromium boride layer having an average layer thickness of 0.8 to 5 μm;
A surface-coated cemented carbide cutting tool that exhibits the wear resistance of the hard coating layer that is excellent in high-speed cutting processing, formed by forming the hard coating layer configured as described above in (a) to (c).

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