JP2006026883A - Surface-coated cemented carbide cutting tool exhibiting excellent wearing-resistance of hard coated layer in high speed cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool in which a hard coated layer exhibits excellent wearing-resistance at high speed cutting. <P>SOLUTION: In the surface coated cemented carbide cutting tool, on a surface of a super-hard substrate comprising tungsten carbide based cemented carbide or titanium carbonitride based cermet, a hard coated layer comprising (a) a Cr boride layer having an average layer thickness of 0.8-5 μm as a surface layer and (b) a composite nitride layer of Ti and Al satisfying a composition formula: (Ti<SB>1-X</SB>Al<SB>X</SB>)N (provided that X represents 0.40-0.75 at an atomic ratio) and having an average layer thickness of 0.8-5 μm as a wearing-resistance hard layer is subjected to physical vapor-deposition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, the hard coating layer is composed of a wear-resistant hard layer having excellent high-temperature hardness and heat resistance, and a surface layer having excellent high-temperature oxidation resistance. A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance over a long period of time even when cutting hard hard-to-cut materials such as Al-Si alloys under high-speed cutting conditions with high heat generation ( Hereinafter, it 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),
Coated carbide formed by physical vapor deposition with an average layer thickness of 1 to 10 μm using a wear-resistant hard layer composed of a composite nitride of Ti and Al [hereinafter referred to as (Ti, Al) N] layer satisfying the following conditions: Tools are known, and 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 same Ti. It is also known to exhibit excellent cutting performance when used for continuous cutting and intermittent cutting of cast iron and the like.

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 wear-resistant hard layer comprising a (Ti, Al) N layer as a hard coating layer.
Japanese Patent No. 2644710

  The performance and automation of cutting machines in recent years have been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and 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 used for the above, 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 during cutting significantly accelerates the wear progression of the wear-resistant hard 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 wear-resistant hard layer is excellent in high-speed cutting of the hard hard-to-cut materials described above. As a result of conducting research focusing on conventional coated carbide tools,
For example, FIG. 1A is a schematic plan view and FIG. 1B is a schematic front view showing an arc ion plating apparatus (hereinafter abbreviated as AIP apparatus) and a sputtering apparatus (hereinafter abbreviated as SP apparatus). ) Coexisting vapor deposition apparatus, that is, Ti--having a predetermined composition as a cathode electrode (evaporation source) of the AIP apparatus on one side of the rotation table with a carbide table mounting rotation table provided at the center of the apparatus. A vapor deposition apparatus in which a sintered body of Cr boride (hereinafter referred to as CrB ₂ ) powder (hereinafter referred to as a CrB ₂ sintered body) is disposed opposite to the Al alloy and the cathode electrode (evaporation source) of the SP apparatus on the other side. In this apparatus, a plurality of carbide substrates are mounted 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. While rotating the rotary table as a gas and rotating the carbide substrate itself for the purpose of uniforming the thickness of the wear-resistant hard layer formed by vapor deposition, basically, the cathode electrode of the Ti-Al alloy ( An arc discharge is generated between the evaporation source) and the anode electrode, and a (Ti, Al) N layer is deposited on the surface of the cemented carbide substrate as an abrasion-resistant hard layer with an average layer thickness of 0.8 to 5 μm. Then, the atmosphere in the vapor deposition apparatus is substantially changed to an Ar atmosphere instead of a nitrogen atmosphere, and sputtering of a CrB ₂ sintered body arranged as a cathode electrode (evaporation source) of the SP apparatus is started. When a CrB ₂ layer is deposited on the (Ti, Al) N layer as a surface layer with an average layer thickness of 0.8 to 5 μm, the resulting coated carbide tool is accompanied by particularly high heat generation. Various Ti alloys and high A surface layer composed of the CrB ₂ layer having excellent high-temperature oxidation resistance, in which the wear-resistant hard layer composed of the (Ti, Al) N layer in high-speed cutting of hard difficult-to-cut materials such as Si-containing Al-Si alloys. Because it is protected from the high-temperature oxidizing atmosphere during cutting and the atmospheric oxidation that causes wear promotion is remarkably suppressed, we have obtained research results that it will exhibit excellent wear resistance over a long period of time. is there.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) As a surface layer, a CrB ₂ layer having an average layer thickness of 0.8 to 5 μm,
(B) As an abrasion resistant hard layer,
Composition formula: (Ti _1-X Al _X ) N (however, in atomic ratio, X represents 0.40 to 0.75),
A (Ti, Al) N layer having an average layer thickness of 0.8 to 5 μm,
The present invention is characterized by a coated cemented carbide tool obtained by physical vapor deposition of the hard coating layer comprising the above (a) and (b) and exhibiting excellent wear resistance in 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 wear resistant hard layer The Al component in the (Ti, Al) N layer constituting the wear resistant hard layer improves high temperature hardness and heat resistance, while the Ti component has high temperature strength. However, if 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 applies hereinafter), the proportion of Ti is relatively increased. The excellent high-temperature hardness and heat resistance required for high-speed cutting can no longer be ensured, and the progress of wear is rapidly accelerated. On the other hand, when the X value indicating the proportion of Al exceeds 0.75, Since the ratio of Ti becomes relatively small, the high-temperature strength rapidly decreases, and as a result, chipping (slight chipping) or the like tends to occur at the cutting edge portion, so that the X value is 0.40 to 0.75. It was determined.

(B) Average layer thickness of wear-resistant hard layer If the average layer thickness is less than 0.8 μm, it is insufficient to exhibit its excellent wear resistance over a long period, while the average layer thickness is If it exceeds 5 μm, chipping is likely to occur at the cutting edge portion in the high-speed cutting of the hard difficult-to-cut material, so the average layer thickness is set to 0.8 to 5 μm.

(C) Average layer thickness of the surface layer As described above, the hard coating layer is composed of the excellent high temperature hardness and heat resistance of the wear resistant hard layer and the excellent high temperature oxidation resistance of the CrB ₂ layer as the surface layer. By coexistence, excellent wear resistance is exhibited by high-speed cutting of hard difficult-to-cut materials with high heat generation. However, when the average layer thickness of the CrB ₂ layer is less than 0.8 μm, It is not enough to protect the wear hard layer from the high-temperature oxidizing atmosphere during 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. The layer thickness was set to 0.8-5 μm.

The coated carbide tool of the present invention has a (Ti, Al) N layer wear-resistant hard layer having excellent high-temperature hardness and heat resistance, excellent high-temperature oxidation resistance, and from a high-temperature oxidizing atmosphere during cutting. A hard coating layer composed of _two surface layers of CrB that protects the wear-resistant hard layer, which exhibits excellent wear resistance even when cutting hard hard-to-cut materials at high speed with high heat generation It is.

  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. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 and ISO standard / CNMG120408. TiCN-based cemented carbide substrates B-1 to B-6 having the following chip shape were formed.

(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. Wear-resistant hard layer forming Ti having a predetermined composition as a cathode electrode (evaporation source) of an AIP device on one side, mounted along a peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table -Al alloy, CrB ₂ sintered body for forming the surface layer as a cathode electrode (evaporation source) of the SP device on the other side is arranged oppositely,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then the carbide substrate that rotates while rotating on the rotary table is set to −1000 V. A DC bias voltage is applied and 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 surface of the carbide substrate 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 vapor-deposited as an abrasion-resistant hard layer of the hard coating layer,
(D) Next, for the purpose of improving the adhesion bonding between the (Ti, Al) N layer as the wear-resistant hard layer already formed by vapor deposition and the CrB ₂ layer as the surface layer to be vapor-deposited from now on, While continuing arc discharge between the cathode electrode and the anode electrode of the wear-resistant hard layer forming Ti—Al alloy, a mixed gas of Ar and nitrogen (N ₂ : Ar = volume ratio) is used instead of nitrogen gas in the apparatus. 3: 1), and the atmosphere in the apparatus is set to 3 Pa. At the same time, the CrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP apparatus is sputtered at an output of 3 kW. Is held for 20 minutes, and a Ti, Al, and Cr composite boronitride layer as an adhesive bonding layer (in this case, the average layer thickness is 0.3 μm in all subsequent measurements, but 0.1 to 0.5 μm). Excellent adhesion with an average layer thickness of Sex is secured) is formed,
(E) Subsequently, the sputtering between the CrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP apparatus and the anode electrode is continued in the same condition (sputtering output: 3 kW) while being introduced into the apparatus. The gas to be used is changed from a mixed gas of Ar and nitrogen to Ar gas, and the atmosphere in the apparatus is set to 0.5 Pa. At the same time, arc discharge between the cathode electrode and the anode electrode of the wear-resistant hard layer forming Ti-Al alloy is performed. The coated carbide tool according to the present invention is stopped and sputtered for a time corresponding to the layer thickness under these conditions, and a CrB ₂ layer having the target layer thickness shown in Table 3 is deposited as a surface layer of the hard coating layer. The present invention surface-coated cemented carbide throwaway tips (hereinafter referred to as the present invention-coated tips) 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 mounted as a cathode electrode (evaporation source), and the inside of the apparatus was first evacuated and kept at a vacuum of 0.1 Pa or less with a 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 a Ti—Al alloy, then nitrogen gas is introduced into the apparatus as a reaction gas to make a reaction atmosphere of 3 Pa, and the bias voltage applied to the carbide substrate is lowered to −100V. Then, arc discharge is generated between the cathode electrode and the anode electrode of the Ti—Al alloy, and the surface of each of the cemented carbide substrates A-1 to A-10 and B-1 to B-6 is displayed on the surface. The conventional surface-coated carbide throwaway as a conventional coated carbide tool is formed by vapor-depositing a wear-resistant hard layer comprising a (Ti, Al) N layer having the target composition and thickness shown in FIG. Chips (hereinafter referred to as conventional 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: Ti-6% Al-4% V alloy round bar by mass%,
Cutting speed: 100 m / min. ,
Incision: 1.5mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
A dry continuous high-speed cutting test of a Ti-based alloy under the following conditions (referred to as cutting condition A) (normal cutting speed is 60 m / min.),
Work material: Al-13% Si alloy round bar by mass%,
Cutting speed: 300 m / min. ,
Cutting depth: 2.0 mm
Feed: 0.15 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed cutting test (normal cutting speed is 180 m / min.) Of a high Si-containing Al—Si based alloy under the above conditions (referred to as cutting condition B),
Work material: Mass%, Al-18% Si alloy lengthwise equidistantly 4 vertical rods with flutes,
Cutting speed: 300 m / min. ,
Incision: 1.5mm,
Feed: 0.18 mm / rev. ,
Cutting time: 10 minutes,
A dry interrupted high-speed cutting test (normal cutting speed is 150 m / min.) Of a high Si content Al-Si alloy under the above conditions (referred to as cutting condition C). The wear width was measured. 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. Made of WC-base cemented carbide with a combination of 4 blade square shape with diameter and length of 6mm × 13mm, 10mm × 22mm, and 20mm × 45mm respectively, and a twist angle of 30 degrees. 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. And a wear-resistant hard layer composed of a (Ti, Al) N layer having the target composition and target layer thickness shown in Table 7 and a surface layer consisting of a CrB ₂ layer having the target layer thickness also shown in Table 7 The surface-coated carbide end mills (hereinafter referred to as the present invention-coated end mills) 1 to 8 as the present invention coated carbide tools were produced by vapor-depositing the hard coating layer composed of

  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. In the same conditions as in Example 1, the wear resistant hard layer comprising the (Ti, Al) N layer having the target composition and the target layer thickness shown in Table 7 is vapor-deposited as a hard coating layer. Conventional surface-coated carbide end mills (hereinafter referred to as conventional coated end mills) 1 to 8 as hard tools 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 Ti-based alloy (mass%, Ti-3% Al-2.5% V alloy) plate material,
Cutting speed: 100 m / min. ,
Groove depth (cut): 2 mm,
Table feed: 800mm / min,
With respect to the dry high-speed grooving test of the Ti-based alloy under the conditions (normal cutting speed is 50 m / min.), 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-6% Al-4% V alloy) plate material,
Cutting speed: 150 m / min. ,
Groove depth (cut): 4 mm
Table feed: 960 mm / min,
With respect to the dry high-speed grooving test of a Ti-based alloy under the conditions (normal cutting speed is 80 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 high Si content Al—Si alloy (mass%, Al-18% Si alloy) plate material,
Cutting speed: 300 m / min. ,
Groove depth (cut): 12 mm,
Table feed: 950 mm / min,
A dry high-speed grooving test (normal cutting speed is 150 m / min.) Of a high-Si-containing Al-Si alloy under the above conditions, and the flank of the outer peripheral edge of the cutting edge in any grooving test The cutting groove length was measured until the wear width reached 0.1 mm, which is a guide for the service life. 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 wear-resistant hard layer composed of the (Ti, Al) N layer having the target composition and target layer thickness shown in Table 8 and CrB having the target layer thickness also shown in Table 8 By vapor-depositing a hard coating layer composed of _two surface layers, the present surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 8 as the present invention coated carbide tools are provided. Each was manufactured.

  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. The device was charged and vapor-deposited as a hard coating layer with a wear-resistant hard layer comprising a (Ti, Al) N layer having the target composition and target layer thickness shown in Table 8 under the same conditions as in Example 1 above. Thus, conventional surface-coated carbide drills (hereinafter referred to as conventional coated drills) 1 to 8 as conventional coated carbide tools were manufactured, respectively.

Next, of the present invention coated drills 1 to 8 and the conventional coated drills 1 to 8, the present invention coated drills 1 to 3 and the conventional coated drills 1 to 3 are:
Work material-plane: 100 mm × 250, 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: 10mm,
With respect to the Ti-based alloy wet high-speed drilling test (normal cutting speed is 30 m / min.), The present invention coated drills 4-6 and the conventional coated drills 4-6,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm Ti-based alloy (mass%, Ti-6% Al-4% V alloy) plate material,
Cutting speed: 75 m / min. ,
Feed: 0.15mm / rev,
Hole depth: 15mm,
With respect to the wet-type high-speed drilling test of a Ti-based alloy under the conditions (normal cutting speed is 40 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: 50 mm high Si content Al—Si alloy (mass%, Al-18% Si alloy) plate material,
Cutting speed: 120 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 30mm,
Wet high-speed drilling test (normal cutting speed is 80 m / min.) Of high Si content Al-Si alloy under the conditions of each, and each wet high-speed drilling test (using water-soluble cutting oil) However, 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 Table 8, respectively.

  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.

  Further, when the average layer thickness of the surface layer of the hard coating layer and the wear-resistant hard layer was measured with a scanning electron microscope, the average value was substantially the same as the target layer thickness (average value of five locations). )showed that.

From the results shown in Tables 3 to 8, the hard coating layer has a high-temperature hardness and heat resistance (Ti, Al) N layer wear-resistant hard layer, excellent high-temperature oxidation resistance, and high temperature during cutting. The coated carbide tool of the present invention composed of _two surface layers of CrB that protects the wear-resistant hard layer from an oxidizing atmosphere is hard hard cutting such as various Ti-based alloys and high Si-containing Al-Si based alloys. In conventional coated carbide tools consisting only of (Ti, Al) N wear-resistant hard layers, while exhibiting excellent wear resistance despite high heat generation in high-speed cutting of materials It is clear that in high-speed cutting with high heat generation, the wear of the cutting edge is fast and the service life is reached in a relatively short time.

  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 in cutting processing and exhibits excellent cutting performance over a long period of time, the performance and automation of cutting equipment, labor saving and energy saving of cutting processing, and lower 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 a cemented carbide substrate made of tungsten carbide based cemented carbide or titanium carbonitride cermet,
(A) As a surface layer, a Cr boride layer having an average layer thickness of 0.8 to 5 μm,
(B) As an abrasion resistant hard layer,
Composition formula: (Ti _1-X Al _X ) N (however, in atomic ratio, X represents 0.40 to 0.75),
And a composite nitride layer of Ti and Al having an average layer thickness of 0.8 to 5 μm,
A surface-coated cemented carbide cutting tool that exhibits high wear resistance in which the hard coating layer is excellent in high-speed cutting, which is obtained by physically vapor-depositing the hard coating layer comprising the above (a) and (b).

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