JP2002254209A - Surface-coated cemented carbide cutting tool whose hard coating layer has excellent chipping resistance in heavy cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool whose hard coating layer has excellent chipping resistance in heavy cutting. SOLUTION: On the surface-coated cemented carbide cutting tool, a hard coating layer having an average thickness of 1 to 10 μm is physically deposited on the surface of a tungsten carbide group cemented carbide substrate or a titanium carbonitride series cermet. The hard coating layer is composed of metallic compound nitride having such a composition formula as (Ti1-( X+ Y) VXMY) N, where M is one type or two or more types among Y, Zr and Hf, X is 0.20 to 0.55 in an atomic ratio, and Y is 0.05 to 0.25 in an atomic ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hard coating layer having excellent toughness, and therefore exhibits excellent chipping resistance especially in heavy cutting conditions such as high feed and high cutting of various steels. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool).

[0002]

2. Description of the Related Art Generally, cutting tools include a throw-away tip which is detachably attached to a tip of a cutting tool for turning or planing of various materials such as steel and cast iron. Drills and miniature drills used for drilling and drilling, and solid type end mills used for face milling and grooving of the work material, shoulder milling, and the like, and the detachable insert is detachably attached. In addition, a throw-away end mill tool or the like that performs cutting in the same manner as the solid type end mill is known.

[0003] As one of the above-mentioned various cutting tools,
In general, for example, an arc ion plating apparatus which is a kind of a physical vapor deposition apparatus schematically shown in FIG. 1 is used, and basically, for example, the atmosphere is set to a vacuum of 1.3 × 10 ⁻³ Pa and the apparatus is heated by a heater. While the inside is heated to a temperature of 500 ° C., an arc is applied between an anode electrode and a cathode electrode (evaporation source) on which an alloy having a predetermined component composition is set, for example, under the conditions of a voltage: 35 V and a current: 100 A. A discharge is generated, and at the same time, a nitrogen gas is introduced as a reaction gas into the apparatus, while a base (hereinafter, referred to as a cermet) based on tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN). , These are collectively referred to as a super-hard substrate), for example, under the condition that a bias voltage of -100 V is applied, the surface of the super-hard substrate is coated with the alloy constituting the cathode electrode. It is also known manufactured coated carbide tool by depositing a hard coating layer made of a composite nitride of the alloy components with an average layer thickness of 1 to 10 [mu] m.

[0004]

On the other hand, in recent years, there has been a strong demand for labor saving, energy saving, and cost reduction in cutting work, and with this, cutting work has been combined with high performance of cutting equipment. Therefore, there is a tendency that cutting is performed under heavy cutting conditions such as high feed and high depth of cut. There is no problem when used for machining, but when it is used for heavy cutting where high toughness is required, chipping (small chipping) occurs at the cutting edge due to insufficient toughness of the hard coating layer At present, it is easy to perform and the service life is reached in a relatively short time.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, among the various coated carbide tools conventionally proposed, in particular, the coated carbide tool described in, for example, Japanese Patent No. 3045184, that is, the above-described arc is formed on the surface of the above-mentioned carbide substrate. Using an ion plating device, Ti and V having high hardness but insufficient toughness
Focusing on a coated carbide tool formed by physical vapor deposition of a hard coating layer made of a metal composite nitride (hereinafter, referred to as (Ti, V) N) with an average layer thickness of 1 to 10 μm, As a result of conducting research to develop a coated carbide tool that provides excellent toughness and has a hard coating layer that exhibits excellent chipping resistance even under heavy cutting conditions such as various steels and cast irons, The composition of the (Ti, V) N layer constituting the hard coating layer of the conventional coated carbide tool is represented by a composition formula: (Ti _1−X V _X )
When represented by N, in atomic ratio, X: 0.20 to 0.55
Is specified, and one or more of Y, Zr, and Hf (hereinafter, referred to as M)
Is the ratio (atomic ratio) in the total amount of Ti and V,
When the solid solution is contained in a proportion satisfying the range from 0.5 to 0.25, the resulting hard coating layer has excellent toughness without impairing the high hardness provided by V, and Coated cemented carbide tools made by physical vapor deposition provide excellent wear resistance over a long period of time without chipping at the cutting edge even when used for cutting under heavy cutting conditions such as high feed and high depth of cut. The research results showed that they would be able to demonstrate their performance.

The present invention has been made on the basis of the above research results, and has a composition formula (T
i _{1- (X + Y)} V _{X MY} ) N (where M is one or more of Y, Zr and Hf, and X is 0.2 in atomic ratio)
0 to 0.55, Y is also 0.05 to 0.25 in atomic ratio
] (Hereinafter, (Ti, V,
M) The hard coating layer is characterized by being coated with a hard coating layer having an average thickness of 1 to 10 μm and having a hard coating layer that exhibits excellent chipping resistance by heavy cutting. It is.

[0007] In the coated carbide tool of the present invention,
The V in (Ti, V, M) N constituting the hard coating layer forms a solid solution with TiN in order to improve the hardness and the heat resistance. Therefore, the composition formula: (Ti _{1− (X + Y) )}
V _X M _Y) at less than 0.20 X value atomic ratio of N can not be ensured the desired hardness and heat resistance, whereas if the X value exceeds the same 0.55, caused by TiN Since the excellent toughness suddenly decreases and chipping easily occurs in the cutting edge portion, the X value is 0.20 to 0.55 in atomic ratio, preferably 0.3 to 0.5. I decided.

[0008] Further, M in the hard coating layer has the function of providing the hard coating layer with excellent toughness as described above and thereby exhibiting excellent chipping resistance in cutting under heavy cutting conditions. : (Ti _{1- (X + Y)} V _{X MY} )
If the Y value of N is less than 0.05 in atomic ratio, desired excellent toughness cannot be secured, while the Y value is 0.25
When it exceeds, the hardness of the hard coating layer rapidly decreases, and the progress of abrasion is promoted.
0.25, desirably 0.1 to 0.2.

Further, the average thickness of the hard coating layer is 1 to 10
The reason why the thickness is set to μm is that if the layer thickness is 1 μm, the desired excellent wear resistance cannot be secured for a long period of time, while if the layer thickness exceeds 10 μm, the hard coating layer is liable to peel off. It is because it becomes.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. (Example 1) As raw material powders, WC powder, TiC powder, ZrC powder, V
C powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, T
An iN powder, a TaN powder, and a Co powder were prepared, and these raw material powders were blended in the blending composition shown in Table 1, wet-mixed in a ball mill for 72 hours, dried, and then dried.
a into a green compact at a pressure of
a. Vacuum, sintering at a temperature of 1400 ° C. for 1 hour, and after sintering, apply a honing process of R: 0.05 to the cutting edge part to obtain a WC base having the shape of ISO standard CNMG120408. Chip cemented carbide substrate A1 to A10 made of cemented carbide
Was formed.

In addition, as raw material powders,
TiCN having an average particle size of 2 μm (by weight ratio TiC /
(TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder were prepared, and these raw material powders were blended into the composition shown in Table 2. After wet-mixing with a ball mill for 24 hours and drying, the mixture is pressed into a green compact at a pressure of 100 MPa, and the green compact is heated in a nitrogen atmosphere of 2 kPa at a temperature of:
After sintering under the condition of holding at 1500 ° C. for 1 hour, after sintering, the cutting edge portion is subjected to a honing process of R: 0.03, and a TiCN-based cermet chip cemented carbide substrate having a shape of ISO standard CNMG120408. B1 to B6 were formed.

Next, the chip carbide substrates A1 to A1
0 and each of B1 to B6 were ultrasonically cleaned in acetone and dried, and each was charged into a normal arc ion plating apparatus illustrated in FIG. 1 while various cathode electrodes (evaporation sources) were used. Ti- with the composition of
After mounting the VM alloy or the Ti-V alloy, and evacuating the inside of the apparatus and keeping the apparatus at a vacuum of 1.3 ^-3 Pa, the inside of the apparatus is heated to 500 ° C. with a heater, and Ar gas is introduced into the apparatus. An Ar atmosphere of 2.5 Pa was introduced, and in this state, a bias voltage of -800 V was applied to the cemented carbide substrate to clean the surface of the cemented carbide substrate with Ar gas bombardment.
And the bias voltage applied to the cemented carbide substrate was reduced to -100 V,
An arc discharge is generated between the cathode electrode and the anode electrode, so that the carbide substrates A1 to A10 and B1
By depositing a hard coating layer having a target composition and a target layer thickness shown in Tables 3 to 5 on each surface of
FIG. 2A is a schematic perspective view, and FIG. 2B is a schematic longitudinal sectional view of the present invention. A coated carbide tip) and a conventional surface coated cemented carbide throwaway tip as a coated carbide tool (hereinafter referred to as a conventionally coated carbide tip) 1 to 30
16 were each manufactured.

With respect to the hard coating layers of the coated superhard tips 1 to 30 of the present invention and the conventional superhard tips 1 to 16 obtained as a result, the center of the thickness section was measured using an Auger spectroscopic analyzer. However, each of them shows substantially the same value as the target composition shown in Tables 3 to 5, and its thickness is measured using a scanning electron microscope. The average value was substantially the same as the thickness (average value measured at five points).

Next, the coated carbide tips 1 to 3 of the present invention will be described.
0 and the conventional coated carbide tips 1 to 16 are screwed to the tip of a tool steel tool with a fixing jig, respectively.
For the coated carbide tips 1 to 19 of the present invention and the conventionally coated carbide tips 1 to 9, the work material is a JIS SCM440 round bar, and the cutting speed is 200 m / min. Infeed: 10 mm, Feed: 0.4 mm / rev. Cutting time: 10 minutes, dry high-cut continuous turning test of alloy steel under the condition of: 10 min. Work material: JIS S40C, 4 longitudinally-elongated round bars at regular intervals in the longitudinal direction, Cutting speed: 200 m / min. , Notch: 4 mm, feed: 0.8 mm / rev. , Cutting time: 10 minutes, a dry high-interruption intermittent turning test of carbon steel was performed.
Workpiece: JIS SCM440C round bar, Cutting speed: 200 m / min. Infeed: 3.5 mm Feed: 0.2 mm / rev. , Cutting time: 10 minutes, Dry high-cut continuous turning test of alloy steel under the condition of: Work material: JIS S40C, 4 longitudinally spaced round bars at equal intervals in the longitudinal direction, Cutting speed: 200 m / min. Infeed: 1.0 mm, Feed: 0.5 mm / rev. A dry high-feed intermittent turning test of carbon steel was performed under the conditions of cutting time: 10 minutes, and the flank wear width of the cutting edge was measured in each turning test. The measurement results are shown in Tables 3 to 5.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

(Example 2) As the raw material powder, the average particle size was as follows:
Medium coarse WC powder having 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, 1.2 μm
NbC powder, 1.2 μm ZrC powder, 2.3 μm
m Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm
μm (Ti, W) C powder, 1.8 μm Co powder,
And 1.2 μm carbon (C) powder were prepared, and these raw material powders were respectively blended into the blending compositions shown in Table 6,
Further, the wax was added, and the mixture was ball-milled in acetone for 24 hours, dried under reduced pressure, and then press-molded at a pressure of 100 MPa into various compacts of a predetermined shape. 13 ° C / min.
The temperature was raised to a predetermined temperature in the range of 70 to 1470 ° C., kept at this temperature for 1 hour, and then sintered under furnace cooling conditions to obtain a diameter of 8 mm.
mm, 13 mm, and 26 mm to form three types of round bar sintered bodies for forming a cemented carbide substrate, and from the three types of round bar sintered bodies, by grinding, in a combination shown in Table 6, The diameter x length of the cutting edge is 6mm x 13mm, 10mm x
End mill superhard substrates a to h having dimensions of 22 mm and 20 mm × 45 mm were produced, respectively.

Next, these end mill super hard substrates a to
h were ultrasonically cleaned in acetone, dried, and charged into a normal arc ion plating apparatus also illustrated in FIG. 1 under the same conditions as in Example 1 above, and Table 7, By depositing a hard coating layer having the target composition and target layer thickness shown in FIG. 8, the shape shown in the schematic front view in FIG. 3A and the schematic cross-sectional view of the cutting edge in FIG. End mill made of the surface-coated cemented carbide of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the coated carbide end mill of the present invention) 1 to 16 and the end mill made of the conventional surface-coated cemented carbide as the conventionally coated carbide tool (Hereinafter referred to as conventional coated carbide end mills) 1 to 8 were manufactured.

The coated carbide end mills 1 to 16 of the present invention and the conventional coated carbide end mills 1 to 8
Of the hard coating layer was measured using an Auger spectrometer at the center of the thickness cross section.
8 shows substantially the same value as the target composition shown in FIG. 8, and its thickness was measured using a scanning electron microscope.
In each case, the average value (the average value of the five-point measurement) was substantially the same as the target layer thickness shown in Tables 7 and 8.

Next, the coated carbide end mill 1 of the present invention will be described.
-16 and conventional coated carbide end mills 1-8, the coated coated carbide end mills 1-6 and the coated conventional carbide end mills 1-3 are as follows: Work material: plane dimension: 100 mm x 250 mm, thickness: 5
0 mm JIS SKD61 plate material, Cutting speed: 30 m / min. Groove depth (cut): 4 mm, Table feed: 130 mm / min, dry high-cut groove cutting test of hardened steel, coated carbide end mills 7 to 12 of the present invention and coated coated end mills of conventional 4 to 6 About: Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SKD11 plate material, Cutting speed: 50 m / min. Groove depth (cut): 12 mm, Table feed: 300 mm / min, dry high-cut groove cutting test of die steel, coated carbide end mills 13 to 16 of the present invention, and coated coated end mills 7,
For No. 8, Work material: Plane dimensions: 100 mm × 250 mm, thickness: 5
JIS S45C plate material of 0 mm, Cutting speed: 120 m / min. , Groove depth (cut): 10 mm, table feed: 800 mm / min, wet high feed groove cutting test of carbon steel (using water-soluble cutting oil) was performed. The flank wear width of the outer peripheral edge of the cutting edge portion is used as a standard of service life.
The cut groove length up to mm was measured. The measurement results are shown in Tables 6 and 7, respectively.

[0024]

[Table 6]

[0025]

[Table 7]

[0026]

[Table 8]

(Example 3) The diameters of 8 mm (for forming the superhard substrates a to c), 13 mm (for forming the superhard substrates d to f), and 26 mm (for the superhard substrate g) produced in Example 2 described above. h
(For forming), the diameter x length of the groove forming portion was 4 mm x 13 mm (the carbide substrate a ') by grinding from the three types of round rod sintered bodies. ~ C '), 8mm
× 22 mm (carbide substrate d ′ to f ′) and 16 mm ×
Drill super hard substrates a 'to h' each having a size of 45 mm (super hard substrates g 'and h') were manufactured.

Next, these drill superhard substrates a 'to
The cutting edge of h ′ is honed, ultrasonically cleaned in acetone, and dried, and then loaded into a normal arc ion plating apparatus also illustrated in FIG. Under conditions, a hard coating layer having a target composition and a target layer thickness shown in Tables 9 and 10 is deposited, so that a schematic front view is shown in FIG. Drills made of the surface-coated cemented carbide of the present invention (hereinafter, referred to as coated carbide drills of the present invention) 1 to 16 as coated carbide tools of the present invention having the shape shown in the plan view, and conventional as coated carbide tools Drills made of surface-coated cemented carbide (hereinafter referred to as conventional coated cemented carbide drills) 1 to 8 were manufactured, respectively.

Further, with respect to the hard coating layers of the coated carbide drills 1 to 16 of the present invention and the conventional coated carbide drills 1 to 8 obtained as described above, the center of the thickness section was measured using an Auger spectroscopic analyzer. Table 9 and 10 respectively
Shows substantially the same value as the target composition shown in Table 2, and the thickness thereof was measured using a scanning electron microscope. As a result, the average was substantially the same as the target layer thickness also shown in Tables 9 and 10. The values (average values of five-point measurements) are shown.

Next, the coated carbide drills 1 to 1 according to the present invention will be described.
6 and the conventional coated carbide drills 1 to 8, the coated carbide drills 1 to 6 of the present invention and the conventional coated carbide drills 1 to 3 are: work material: plane dimension: 100 mm × 250 thickness: 10 mm
JIS SCM440 plate material, Cutting speed: 80 m / min. , Feed: 0.35 mm / rev, wet high-feed drilling cutting test of alloy steel (using water-soluble cutting oil), coated carbide drills 7 to 12 of the present invention and conventional coated carbide drills 4 to 4
About 6, work material: plane dimensions: 100 mm x 250 mm, thickness: 2
0 mm JIS S50C plate, Cutting speed: 60 m / min. , Feed: 0.40 mm / rev, wet high-feed drilling test of carbon steel (using water-soluble cutting oil), coated carbide drills 13 to 16 of the present invention, and coated carbide drills 7 and 8 of the prior art , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 4
5 mm JIS SCM435 plate, Cutting speed: 60 m / min. , Feed: 0.45 mm / rev, a wet high-feed drilling cutting test (using water-soluble cutting oil) of alloy steel was conducted under the conditions of 0.45 mm / rev. The number of holes drilled until the flank wear width reached 0.3 mm was measured. The measurement results are shown in Tables 9 and 10, respectively.

[0031]

[Table 9]

[0032]

[Table 10]

[0033]

From the results shown in Tables 3 to 10, the hard coating layer has high hardness and excellent toughness (Ti, V, M)
The coated carbide tool of the present invention composed of an N layer, even if the cutting of steel is performed under heavy cutting conditions of high depth of cut and high feed,
The conventional coated carbide tool, in which the hard coating layer is composed of a (Ti, V) N layer, exhibits excellent wear resistance without occurrence of chipping in the cutting edge portion. In the cutting process, chipping occurs at the cutting edge portion due to insufficient toughness of the hard coating layer, and this significantly promotes the progress of wear, so that it is clear that the service life can be reached in a relatively short time. As described above, the coated carbide tool of the present invention is excellent not only in cutting under various conditions such as steel and cast iron, but also in cutting under high cutting conditions and high feed heavy cutting conditions. Since it exhibits chipping resistance and exhibits excellent wear resistance over a long period of time, it can sufficiently cope with labor saving and energy saving of cutting work, and furthermore, cost reduction.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an arc ion plating apparatus.

FIG. 2A is a schematic perspective view of a coated carbide tip, and FIG.
1 is a schematic longitudinal sectional view of a coated carbide tip.

FIG. 3A is a schematic front view of a coated carbide end mill,
(B) is a schematic cross-sectional view of the cutting blade portion.

FIG. 4A is a schematic front view of a coated carbide drill, and FIG.
FIG. 3 is a schematic cross-sectional view of the groove forming portion.

[Procedure amendment]

[Submission date] March 26, 2001 (2001.3.2)
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

In addition, as raw material powders,
TiCN having an average particle size of 2 μm (by weight ratio TiC /
(TiN = 50/50) powder, Mo ₂ C powder , ZrC powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder were prepared, and these raw material powders were blended into the composition shown in Table 2. After wet-mixing with a ball mill for 24 hours and drying, the mixture is pressed into a green compact at a pressure of 100 MPa, and the green compact is heated in a nitrogen atmosphere of 2 kPa at a temperature of:
After sintering under the condition of holding at 1500 ° C. for 1 hour, after sintering, the cutting edge portion is subjected to a honing process of R: 0.03, and a TiCN-based cermet chip cemented carbide substrate having a shape of ISO standard CNMG120408. B1 to B6 were formed.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Next, the coated carbide end mill 1 of the present invention will be described.
-16 and conventional coated carbide end mills 1-8, the coated coated carbide end mills 1-6 and the coated conventional carbide end mills 1-3 are as follows: Work material: plane dimension: 100 mm x 250 mm, thickness: 5
0 mm JIS SKD61 plate material, Cutting speed: 30 m / min. , Groove depth (cut): 4 mm, table feed: 130 mm / min. , Dry type high cutting groove cutting test of quenched steel under the following conditions, coated carbide end mills 7 to 12 of the present invention and conventional coated carbide end mills 4 to 6
About: Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SKD11 plate material, Cutting speed: 50 m / min. , Groove depth (cut): 12 mm, table feed: 300 mm / min. , The dry-type high-cut groove cutting test of the die steel, the coated carbide end mills 13 to 16 of the present invention, and the conventionally coated carbide end mills 7 and 8 are as follows: Work material: plane dimension: 100 mm × 250 mm, thickness Sa: 5
0 mm JIS S45C plate, Cutting speed: 120 m / min. , Groove depth (cut): 10 mm, table feed: 800 mm / min. , Wet high feed groove cutting test of carbon steel under conditions (using water-soluble cutting oil),
In each of the groove cutting tests, the flank wear width of the outer peripheral edge of the cutting edge portion is used as a guide for the service life.
The cutting groove length up to 1 mm was measured. The measurement results are shown in Tables 6 and 7, respectively. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 7, 2001 (2001.8.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Next, the chip carbide substrates A1 to A1
0 and each of B1 to B6 were ultrasonically cleaned in acetone and dried, and each was charged into a normal arc ion plating apparatus illustrated in FIG. 1 while various cathode electrodes (evaporation sources) were used. Ti- with the composition of
After mounting the VM alloy or the Ti-V alloy, and evacuating the inside of the apparatus and keeping the apparatus at a vacuum of 1.3 × 10 ⁻³ Pa , the inside of the apparatus is heated to 500 ° C. with a heater, and then Ar gas is supplied. Into a 2.5 Pa Ar atmosphere, and in this state, applying a bias voltage of -800 V to the cemented carbide substrate to clean the surface of the cemented carbide substrate with Ar gas bombardment. (Reactive gas) atmosphere and the bias voltage applied to the superhard substrate is -100 V
And an arc discharge is generated between the cathode electrode and the anode electrode.
By depositing a hard coating layer having a target composition and a target layer thickness shown in Tables 3 to 5 on the respective surfaces of B1 and B1 to B6, a schematic perspective view is shown in FIG. A throw-away tip made of a surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention having a shape shown in a vertical cross-sectional view (hereinafter, referred to as the coated cemented carbide tip of the present invention) 1 to 30;
In addition, conventional surface-coated cemented carbide throwaway tips (hereinafter, referred to as conventionally coated cemented carbide tips) 1 to 16 as conventional coated cemented carbide tools were manufactured, respectively.

Continuation of the front page (72) Inventor Yusuke Tanaka 179 Kanegasaki Nishi-Oike, Uozumi-machi, Akashi-shi, Hyogo 1 FMC Term, FMC Term (Reference) 3C037 CC01 CC04 CC09 CC11 3C046 AA01 FF03 FF05 FF10 FF11 FF19 FF25 4K029 AA04 BA58 BC00 BD05 EA01

Claims (1)

[Claims] 1. The method according to claim 1, wherein a surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate has a composition formula: (T
i _{1- (X + Y)} V _{X MY} ) N (where M is one or more of Y, Zr and Hf, and X is 0.2 in atomic ratio)
0 to 0.55, Y is also 0.05 to 0.25 in atomic ratio
A hard coating layer made of a metal composite nitride having a thickness of 1 to 10 μm by physical vapor deposition. Cutting tools.