Surface-coated cutting tool providing excellent chipping resistance and wear resistance in heavy intermittent cutting

Abstract

Provided is a surface-coated cutting tool including: a tool body (3) and a hard coating layer on the tool body (3). The hard coating layer has an alternate laminate structure of A (1) and B layers (2). The A layer (1) is a Ti and Al complex nitride layer satisfying a compositional formula: (Ti.sub.1-zAl.sub.z)N, 0.4z0.7. The B layer (2) is a Cr, Al and M complex nitride layer satisfying a compositional formula: (Cr.sub.1-x-yAl.sub.xM.sub.y)N, 0.03x0.4 and 0y0.05. The value of a ratio tB/tA of the average layer thickness of the B layer (2) to the average layer thickness of the A layer (1) satisfies 0.67 to 2.0. The lattice constant a() of crystal grains of the hard coating layer satisfies 4.10a4.20. The ratio of I(200) to I(111) satisfies 2.0I(200)/I(111)10.

Claims

1. A surface-coated cutting tool comprising: a tool body made of a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet or a cubic boron nitride sintered material; and a hard coating layer provided on a surface of the tool body, the hard coating layer being made of an alternate laminate structure, in which at least one A layer and at least one B layer are laminated, and having a total thickness of 0.5-3.0 m, wherein (a) the A layer is a complex nitride layer of Ti and Al satisfying a compositional formula: (Ti.sub.1-zAl.sub.z)N, 0.4z0.7, z being a content ratio of Al in an atomic ratio, (b) the B layer is a complex nitride layer of Cr, Al, and M satisfying a compositional formula: (Cr.sub.1-x-yAl.sub.xM.sub.y)N, 0.03x0.4 and 0.01<y0.05, x being a content ratio of Al in an atomic ratio, y being a total content ratio of a component M in an atomic ratio, and component M being one or more elements selected from: B, Si, and V, (c) when an average layer thickness of the A layer is tA and an average layer thickness of the B layer is tB, a value of a ratio tB/tA satisfies 0.67 to 2.0, (d) a lattice constant a() of crystal grains that constitute the hard coating layer made of the A layer and the B layer calculated from a diffraction peak angle of a (200) plane obtained by X-ray diffraction of the entire hard coating layer made of the A layer and the B layer satisfies 4.10a4.20, and (e) when an X-ray diffraction peak intensity of the (200) plane is I(200) and an X-ray diffraction peak intensity of a (111) plane is I(111), each of I(200) and I(111) being obtained by the X-ray diffraction of the entire hard coating layer made of the A layer and the B layer, 2.0I(200)/I(111)10 is satisfied.

2. The surface-coated cutting tool according to claim 1, wherein a value of a plastic deformation work ratio W.sub.plast/(W.sub.plast+W.sub.elast), which is obtained by performing a nanoindentation test at an indentation depth of 1/10 or less of a layer thickness of the B layer, is within a range of 0.35 to 0.50.

3. The surface-coated cutting tool according to claim 1, wherein the hard coating layer comprises plural A layers and plural B layers are alternately laminated.

4. The surface-coated cutting tool according to claim 3, wherein the average thickness of the plural A layers is in a range of 0.4 to 0.8 m, and the average thickness of the plural B layers is in a range of 0.4 to 0.8 m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an example of a longitudinal cross-sectional schematic diagram of a hard coating layer of a coated tool of the present invention.

(2) FIG. 2A shows a schematic plan view of an arc ion plating apparatus used in forming the hard coating layer.

(3) FIG. 2B shows a schematic front view of the arc ion plating apparatus used in forming the hard coating layer.

(4) FIG. 3 shows an example of an X-ray diffraction chart measured with respect to the coated tool of the present invention.

(5) FIG. 4 shows a view for schematically explaining a test method to obtain a plastic deformation work ratio.

(6) FIG. 5 is a view for schematically explaining a load curve of a displacement-load and an unloading curve of the displacement-load obtained by the test method of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

(7) Next, a coated tool of the present invention will be exemplarily described in detail.

(8) Further, while a coated tool constituted by a tool body formed of a tungsten carbide (WC)-based cemented carbide and a coated tool constituted by a tool body formed of a cubic boron nitride (cBN) sintered material will be described as a specific example, a coated tool using a titanium carbonitride-based cermet as a tool body will also be described similarly.

Example 1

(9) Production of Tool Body:

(10) A Co powder, a TiC powder, a VC powder, a TaC powder, an NbC powder, a Cr.sub.3C.sub.2 powder, and a WC powder, all of which have an average grain size of 0.5 to 5 m, were prepared as raw powders, these raw powders were blended into a blending composition shown in Table 1 and then mixed in a ball mill for 72 hours through wet mixing by adding wax, the mixed raw powders were decompressed and dried, and then the dried raw powders were pressed at a pressure of 100 MPa to sinter a green compact of these powders, and the sintered material was machined to have a predetermined dimension to form tool bodies 1 to 3 of the WC-based cemented carbide having an insert shape of ISO Standard SEEN 1203 AFTN1 were manufactured.

(11) TABLE-US-00001 TABLE 1 Blending composition (mass %) Tool body type Co TiC VC TaC NbC Cr.sub.3C.sub.2 WC 1 7.5 2.0 2.5 balance 2 12.0 1.0 0.5 balance 3 9.5 2.0 1.5 0.5 balance
Film Forming Process:

(12) Using an arc ion plating apparatus (4) shown in FIGS. 2A and 2B with respect to the tool bodies 1 to 3 formed of the WC-based cemented carbide,

(13) (a) the tool bodies 1 to 3 were mounted on an outer circumferential section at positions spaced a predetermined distance from a central axis in a radial direction on a rotating table (6) in the arc ion plating apparatus (4) in a state in which the tool bodies were ultrasonically cleaned in acetone and dried.

(14) (b) First, after the inside of the apparatus was heated to 500 C. by a heater (5) while holding vacuum of 10.sup.2 Pa or less by evacuating the inside of the apparatus, the inside was set to an Ar gas atmosphere of 0.5 to 2.0 Pa, a direct current bias voltage of 200 to 1000V was applied to the tool body (3) that was rotated while being autorotated on the rotating table (6), and bombarding processing was performed on a surface of the tool body (3) using argon ions for 5 to 30 minutes.

(15) (c) Next, a hard coating layer formed in an alternating laminated structure was formed as follows.

(16) First, the inside of the apparatus was maintained at a temperature in the apparatus shown in Table 2, rotation was similarly suppressed to the rotation number of the rotating table (6) shown in Table 2, and when an A layer was formed, nitrogen gas was introduced into the apparatus as a reactant gas to form a predetermined reaction atmosphere within a range of 2 to 10 Pa shown in Table 2, a predetermined direct current bias voltage within a range of 25 to 75V shown in Table 2 was applied to the tool body (3) that was rotated while being autorotated on the rotating table (6), and a predetermined current within a range of 90 to 140 A shown in Table 2 flowed through a cathode electrode (a vapor source) (7) for forming the A layer to generate an arc discharge. Next, when a B layer was formed, nitrogen gas was introduced into the apparatus as the reactant gas to form a predetermined reaction atmosphere within a range of 2 to 10 Pa shown in Table 2, a predetermined direct current bias voltage within a range of 25 to 75V shown in Table 2 was applied to the tool body (3) that was rotated while being autorotated on the rotating table (6), a predetermined current within a range of 90 to 140 A shown in Table 2 flowed similarly through a cathode electrode (a vapor source) (9) for forming the B layer to generate an arc discharge, and a hard coating layer formed in an alternating laminated structure having a target composition and further a target average layer thickness of one layer of the A layer (1) and the B layer (2) shown in Table 4 was deposited on surfaces of the tool bodies 1 to 3, and thus, coated tools of the present invention (referred to as tools of the present invention) 1 to 6 shown in Table 4 were produced.

(17) Further, in the deposition film-forming process of (a) to (c), in particular, a lattice constant of crystal grains of the entire hard coating layer constituted by the A layer (1) and the B layer (2) was controlled by adjusting a bias voltage in a deposition condition of the A layer (1) and the B layer (2), in addition, an orientation of the crystal grains of the entire hard coating layer constituted by the A layer (1) and the B layer (2) was controlled by adjusting an arc current value, a partial pressure of nitrogen gas as the reactant gas, the bias voltage, a depositing temperature, and the like such that a hard coating layer having a lattice constant a and an X-ray diffraction peak intensity ratio I(200)/I(100) shown in Table 4 was formed.

(18) While FIG. 3 shows an example of an X-ray diffraction result measured with respect to a hard coating layer of the tool 3 of the present invention, it should be appreciated that a value of a ratio I(200)/I(111) of a (200) plane diffraction peak intensity I(200) and a (111) plane diffraction peak intensity I(111) of the entire hard coating layer constituted by the A layer (1) and the B layer (2) was 5.53, and a lattice constant a calculated from a (200) plane diffraction peak angle of the B layer (2) was 4.17 .

(19) For comparison, with respect to the tool bodies 1 to 3, like Example 1, under the condition shown in Table 3, the coated tools (referred to as tools of Comparative Example) 1 to 6 of Comparative Example shown in Table 5 were produced by depositing a hard coating layer having an alternating laminated structure constituted by the A layer (1) and the B layer (2) thereon.

(20) In the tools 1 to 6 of the present invention and the tools 1 to 6 of Comparative Example as produced above, a composition of the A layer (1) and the B layer (2) and further a layer thickness were measured at a plurality of places through cross-sectional measurement of a longitudinal cross section of the hard coating layer using a scanning electron microscopy (SEM), a transmission electron microscope (TEM), or an energy dispersive X-ray spectroscopy (EDS), and the composition and an average layer thickness of one layer were calculated by averaging them.

(21) In addition, an orientation of the entire hard coating layer constituted by the A layer (1) and the B layer (2) was calculated from values of overlapping X-ray diffraction peak intensities I(200) and I(111) of the A layer (1) and the B layer (2) measured through X-ray diffraction using a Cr bulb. In addition, a lattice constant of the entire hard coating layer constituted by the A layer (1) and the B layer (2) was calculated from an angle of an X-ray diffraction peak of a (200) plane (see FIG. 3).

(22) FIG. 3 shows X-ray diffraction results measured with respect to the hard coating layer of the tool 3 of the present invention.

(23) In addition, in the B layers (2) serving as the outermost surface layers of the hard coating layers of the tools 1 to 6 of the present invention and the tools 1 to 6 of Comparative Example as produced above, since a nanoindentation test is performed with an indentation depth of 1/10 or less of a layer thickness of B layer (2) (see FIG. 4), the surface of the B layer (2) was displaced, a load curve of a displacement-load and an unloading curve of the displacement-load were obtained (see FIG. 5), a plastic deformation work ratio W.sub.plast and an elastic deformation work W.sub.elast were obtained from a difference between the load curve and unloading curve, and a plastic deformation work ratio W.sub.plast/(W.sub.plast+W.sub.elast) was calculated from these values.

(24) FIG. 5 shows a view schematic explaining a load curve of a displacement-load and an unloading curve of the displacement-load measured with respect to the B layer (2) of the hard coating layer of the tool 3 of the present invention. Further, a test load was determined according to a layer thickness of the tool such that an indentation depth becomes an indentation depth of 1/10 or less of the layer thickness of the B layer (2) even in a sample having the smallest layer thickness of the B layer (2) of the outermost surface in samples that are simultaneously measured. In the measurement results shown in FIG. 5, it was confirmed that the test was performed at a test load of 200 mgf and the indentation depth was 1/10 or less of the layer thickness of the B layer (2). Various values obtained as above are shown in Table 4 and Table 5.

(25) TABLE-US-00002 TABLE 2 Deposition conditions Deposition conditions Deposition conditions upon A layer formation upon B layer formation Rotating Direct Direct table current current Tool Cathode electrode (target) type Temperature rotation N.sub.2 gas bias Arc N.sub.2 gas bias Arc body For forming For forming in apparatus speed pressure voltage current pressure voltage current Type type A layer B layer ( C.) (rpm) (Pa) (V) (A) (Pa) (V) (A) Tools of 1 1 Al0.60Ti0.40 Cr0.67Al0.30Si0.03 400 1.5 6.0 40 140 4.0 40 120 the 2 2 Al0.50Ti0.50 Cr0.90Al0.05V0.05 450 3.0 2.0 70 140 4.0 50 140 present 3 3 Al0.55Ti0.45 Cr0.70Al0.30 450 2.0 6.0 25 100 6.0 40 100 invention 4 1 Al0.65Ti0.35 Cr0.80Al0.20 500 1.5 10.0 25 90 10.0 30 90 5 2 Al0.70Ti0.30 Cr0.79Al0.20Si0.01 500 2.0 8.0 40 90 8.0 50 90 6 3 Al0.45Ti0.55 Cr0.88Al0.10B0.02 400 3.0 6.0 25 100 6.0 26 100

(26) TABLE-US-00003 TABLE 3 Deposition conditions Deposition conditions Deposition conditions upon A layer formation upon B layer formation Rotating Direct Direct table current current Tool Cathode electrode (target) type Temperature rotation N.sub.2 gas bias Arc N.sub.2 gas bias Arc body For forming For forming in apparatus speed pressure voltage current pressure voltage current Type type A layer B layer ( C.) (rpm) (Pa) (V) (A) (Pa) (V) (A) Tools of 1 1 Al0.5Ti0.5 Cr0.69Al0.30Si0.01 400 3.0 1.0 50 180.0 2.0 25 160 comparative 2 2 Al0.65Ti0.35 Cr0.55Al0.40Si0.05 350 3.0 0.5 100 160.0 1.0 75 160 example 3 3 Al0.6Ti0.4 Cr0.80Al0.20 550 1.5 10.0 25 80.0 12.0 100 90 4 1 Al0.7Ti0.3 Cr0.60Al0.40 450 2.0 2.0 10 80.0 6.0 25 160 5 2 Al0.55Ti0.45 Cr0.89Al0.10V0.01 500 1.5 14.0 75 80.0 10.0 100 100 6 3 Al0.45Ti0.55 Cr0.65Al0.30B0.05 350 2.0 1.0 75 160.0 1.0 10 140

(27) TABLE-US-00004 TABLE 4 Hard coating layer of alternating lamination structure A layer B layer X-ray Layer Average Layer Layer Average diffraction Plastic Layer Total compo- layer Type of compo- compo- layer peak deformation thick- layer Tool sition thickness M sition sition thickness intensity Lattice work ness thick- body (value of one compo- (value (value of one ratio constant ratio of ratio ness Type type of z) layer (m) nent of x) of y) layer (m) I(200)/I(111) () B layer (tB/tA) (m) Tools of 1 1 0.58 0.4 Si 0.28 0.03 0.5 3.66 4.15 0.37 1.3 2.7 the 2 2 0.48 0.4 V 0.04 0.05 0.5 2.39 4.18 0.48 1.3 1.8 present 3 3 0.52 0.5 0.29 0.00 0.6 5.53 4.17 0.38 1.2 1.1 invention 4 1 0.63 0.4 0.19 0.00 0.8 8.37 4.14 0.43 2.0 2.4 5 2 0.67 0.8 Si 0.18 0.01 0.6 7.18 4.12 0.40 0.8 1.4 6 3 0.40 0.4 B 0.09 0.02 0.4 4.24 4.19 0.45 1.0 0.8

(28) TABLE-US-00005 TABLE 5 Hard coating layer of alternating lamination structure A layer B layer X-ray Layer Average Layer Layer Average diffraction Plastic Layer Total compo- layer Type of compo- compo- layer peak deformation thick- layer Tool sition thickness M sition sition thickness intensity Lattice work ness thick- body (value of one compo- (value (value of one ratio constant ratio of ratio ness Type type of z) layer (m) nent of x) of y) layer (m) I(200)/I(111) () B layer (tB/tA) (m) Tools of 1 1 0.48 0.5 Si 0.28 0.01 0.3 *0.96 4.17 0.36 *0.6 0.8 comparative 2 2 0.62 0.8 Si 0.37 0.04 0.7 *1.27 4.15 0.28 0.9 1.5 example 3 3 0.58 0.4 0.17 0.00 0.4 *11.4 4.17 0.39 1.0 1.6 4 1 0.68 0.5 0.39 0.00 0.5 2.78 *4.09 0.35 1.0 1.0 5 2 0.52 0.3 V 0.07 0.01 0.5 *12.2 *4.21 0.45 1.7 2.4 6 3 0.42 0.4 B 0.27 0.05 1.0 *1.69 4.18 0.32 *2.5 2.8 *shows items outside of the scope of the claim of the instant US application.

(29) Next, in the tools 1 to 6 of the present invention and the tools 1 to 6 of Comparative Example, a high speed face milling test of a single blade was performed under the following conditions.

(30) Cutting Condition B:

(31) Workpiece: block material of JIS/S45C (width 70 mmlength 300 mm),

(32) Cutting speed: 160 m/min,

(33) Rotational speed: 408 rev/min,

(34) Depth of cut: 2.5 mm,

(35) Feed: 0.20 mm/blade, and

(36) Width of cut: 70 mm

(37) Cutting was performed to a cutting length 1600 m and a width of a flank wear was measured under the above-mentioned conditions. In addition, the existence of the occurrence of chipping was observed.

(38) Test results are shown in Table 6.

(39) TABLE-US-00006 TABLE 6 Width Exis- Width Exis- of flank tence of flank tence wear of wear of Type (mm) chipping Type (mm) chipping Tools of 1 0.13 None Tools of 1 *9 Exist the 2 0.17 None Compar- 2 *6 Exist present 3 0.09 None ative 3 *8 Exist inven- 4 0.14 None example 4 0.21 None tion 5 0.10 None 5 *6 Exist 6 0.12 None 6 *4 Exist *shows a cutting time (min) until a life time due to occurrence of chipping.

Example 2

(40) Production of Tool Body:

(41) A raw powders for forming a bonded phase of a TiN powder, a TiCN powder, an Al powder, an AlN powder, and an Al.sub.2O.sub.3 powder, all of which have an average grain size of 2.0 m or less were prepared as raw powders while preparing raw powders for forming a hard phase of cBN particles having an average grain size of 1.0 m.

(42) The raw powders were blended at a blending ratio shown in Table 1 such that a content ratio of cBN particles when a content of some of the raw powders from these raw powders and a cBN powder is 100 volume % becomes 40 to 80 volume %.

(43) Next, after the raw powders were mixed by a ball mill for 72 hours through wet mixing and then dried, the raw powders were pressed at a dimension of a diameter: 50 mmthickness: 1.5 mm at a molding pressure of 100 MPa, the green compact was held at a predetermined temperature within a range of 900 to 1300 C. under a vacuum atmosphere of a pressure: 1 Pa or less to be temporarily sintered, and then, a cBN sintered material was formed by loading the temporarily sintered material into an ultrahigh pressure sintering apparatus and sintering the temporally sintered material at a pressure: 5 GPa and a predetermined temperature within a range of 1200 to 1400 C.

(44) The sintered material was cut to a predetermined dimension by a wire electric discharge machine, a brazing section (a corner section) of an insert main body formed of a WC-based cemented carbide having a composition of Co: 5mass %, TaC: 5mass %, WC: balance and an insert shape of ISO Standard CNGA 120408 was brazed using an Ag-based brazing filler material having a composition of Cu: 26%, Ti: 5%, Ag: balance in mass %, and cBN tool bodies 11 to 13 having an insert shape of ISO Standard CNGA 120408 were manufactured by performing grind on upper and lower surfaces and an outer circumference and honing processing.

(45) TABLE-US-00007 TABLE 7 Blending composition (volume %) Tool body type TiN TiCN Al AlN Al.sub.2O.sub.3 cBN 11 26 31 3 40 12 26 13 1 60 13 12 7 1 80

(46) Next, like the case of Example 1, as the hard coating layer is deposited on the cBN tool bodies 11 to 13 under the conditions shown in Table 8 using the arc ion plating apparatus (4) shown in FIGS. 2A and 2B, the coated tools of the present invention shown in Table 10 (referred to as tools of the present invention) 11 to 16 on which the hard coating layer formed in the alternating laminated structure of the A layer (1) and the B layer (2) is deposited were produced.

(47) For comparison, as the hard coating layer is deposited on the tool bodies 11 to 13 under the conditions shown in Table 9, the coated tools of Comparative Example shown in Table 11 (referred to tools of Comparative Example) 11 to 16 were produced.

(48) With respect to the tools 11 to 16 of the present invention and the tools 11 to 16 of Comparative Example produced as above, like Example 1, compositions of layers and an average layer thickness of one layer were calculated.

(49) In addition, an orientation and a lattice constant of the entire hard coating layer constituted by the A layer (1) and the B layer (2) were calculated from values of the measured X-ray diffraction peak intensities I(200) and I(111).

(50) Further, the same nanoindentation test as Example 1 was performed with respect to the B layer (2), and a plastic deformation work ratio W.sub.plast/(W.sub.plast+W.sub.elast) was calculated from the load curve of the displacement-load and the unloading curve of the displacement-load.

(51) Various values obtained as described above are shown in Tables 10 and 11.

(52) TABLE-US-00008 TABLE 8 Deposition conditions Deposition conditions Deposition conditions upon A layer formation upon B layer formation Rotating Direct Direct Temperature table current current Tool Cathode electrode (target) type in rotation N.sub.2 gas bias Arc N.sub.2 gas bias Arc body For forming For forming apparatus speed pressure voltage current pressure voltage current Type type A layer B layer ( C.) (rpm) (Pa) (V) (A) (Pa) (V) (A) Tools of 11 11 Al0.66Ti0.35 Cr0.80Al0.20 500 1.5 10.0 25 90 10.0 30 90 the 12 12 Al0.55Ti0.45 Cr0.70Al0.30 450 2.0 6.0 25 100 6.0 40 100 present 13 13 Al0.60Ti0.40 Cr0.67Al0.30Si0.03 400 1.5 6.0 40 140 4.0 40 120 invention 14 11 Al0.70Ti0.30 Cr0.79Al0.20Si0.01 500 2.0 8.0 40 90 8.0 50 90 15 12 Al0.45Ti0.55 Cr0.88Al0.10B0.02 400 3.0 6.0 25 100 6.0 25 100 16 13 Al0.50Ti0.50 Cr0.90Al0.05V0.05 450 3.0 2.0 70 140 4.0 50 140

(53) TABLE-US-00009 TABLE 9 Deposition conditions Deposition conditions Deposition conditions upon A layer formation upon B layer formation Rotating Direct Direct table current current Tool Cathode electrode (target) type Temperature rotation N.sub.2 gas bias Arc N.sub.2 gas bias Arc body For forming For forming in apparatus speed pressure voltage current pressure voltage current Type type A layer B layer ( C.) (rpm) (Pa) (V) (A) (Pa) (V) (A) Tools of 11 11 Al0.45Ti0.55 Cr0.65Al0.30B0.05 350 2.0 1.0 75 160.0 1.0 10 140 comparative 12 12 Al0.6Ti0.4 Cr0.80Al0.20 550 1.5 10.0 25 80.0 12.0 100 90 example 13 13 Al0.5Ti0.5 Cr0.69Al0.30Si0.01 440 3.0 1.0 50 180.0 2.0 25 160 14 11 Al0.55Ti0.45 Cr0.89Al0.10V0.01 500 1.5 14.0 75 80.0 10.0 100 100 15 12 Al0.7Ti0.3 Cr0.60Al0.40 450 2.0 2.0 10 80.0 6.0 25 160 16 13 Al0.65Ti0.35 Cr0.55Al0.40Si0.05 350 3.0 0.5 100 160.0 1.0 75 160

(54) TABLE-US-00010 TABLE 10 Hard coating layer of alternating lamination structure A layer B layer X-ray Layer Average Layer Layer Average diffraction Plastic Layer Total compo- layer Type of compo- compo- layer peak deformation thick- layer Tool sition thickness M sition sition thickness intensity Lattice work ness thick- body (value of one compo- (value (value of of one ratio constant ratio of ratio ness Type type of z) layer (m) nent of x) y) layer (m) I(200)/I(111) () B layer (tB/tA) (m) Tools of 11 11 0.62 0.4 0.19 0.00 0.8 8.65 4.14 0.42 2.0 2.4 the 12 12 0.53 0.5 0.28 0.00 0.6 5.36 4.17 0.39 1.2 1.1 present 13 13 0.58 0.4 Si 0.29 0.03 0.5 3.81 4.15 0.36 1.3 2.7 invention 14 11 0.67 0.8 Si 0.18 0.01 0.6 7.23 4.13 0.41 0.8 1.4 15 12 0.43 0.4 B 0.10 0.02 0.4 4.32 4.19 0.44 1.0 0.8 16 13 0.47 0.4 V 0.04 0.04 0.5 2.17 4.18 0.46 1.3 1.8

(55) TABLE-US-00011 TABLE 11 Hard coating layer of alternating lamination structure A layer B layer X-ray Layer Average Layer Layer Average diffraction Plastic Layer Total compo- layer Type of compo- compo- layer peak deformation thick- layer Tool sition thickness M sition sition thickness intensity Lattice work ness thick- body (value of one compo- (value (value of one ratio constant ratio of B ratio ness Type type of z) layer (m) nent of x) of y) layer (m) I(200)I(111) () layer (tB/tA) (m) Tools of 11 11 0.43 0.4 B 0.27 0.05 1.0 *1.87 4.19 0.31 *2.5 2.8 comparative 12 12 0.59 0.4 0.18 0.00 0.4 *11.2 4.16 0.41 1.0 1.6 example 13 13 0.47 0.5 Si 0.28 0.01 0.3 *1.43 4.17 0.37 *0.6 0.8 14 11 0.51 0.3 V 0.07 0.01 0.5 *12.1 *4.21 0.46 1.7 2.4 15 12 0.69 0.5 0.39 0.00 0.5 2.62 *4.09 0.36 1.0 1.0 16 13 0.63 0.8 Si 0.36 0.03 0.7 *1.36 4.15 0.29 0.9 1.5 *shows items outside of the scope of the claim of the instant US application.

(56) Next, in the tools 11 to 16 of the present invention and the tools 11 to 16 of Comparative Example, like the case of Example 1, the cutting test was performed under the following conditions.

(57) Workpiece: round bar with 8 longitudinal grooves formed equal intervals in the longitudinal direction of JIS/SCr420 (60HRC),

(58) Cutting speed: 130 m/min,

(59) Depth of cut: 0.2 mm,

(60) Feed: 0.10 mm/rev.,

(61) Cutting time: 30 minutes.

(62) A dry heavy intermittent cutting test of chrome steel under the above-mentioned conditions was performed, a width of flank wear of a blade was measured, and the existence of the occurrence of chipping was observed.

(63) Test results are shown in Table 12.

(64) TABLE-US-00012 TABLE 12 Width Exis- Width Exis- of flank tence of flank tence wear of wear of Type (mm) chipping Type (mm) chipping Tools of 11 0.09 None Tools of 11 *12 Exist the 12 0.06 None Compar- 12 *26 Exist present 13 0.09 None ative 13 *24 Exist inven- 14 0.07 None Example 14 *19 Exist tion 15 0.08 None 15 0.14 None 16 0.11 None 16 *17 Exist *shows a cutting time (min) until a life time due to occurrence of chipping.

(65) According to the results of Table 6, in the tools 1 to 6 of the present invention, while an average of a width of a flank wear was about 0.08 mm, the tools 1 to 6 of Comparative Example had short life times due to the progression of flank wear and the occurrence of chipping over a short time.

(66) In addition, according to the results of Table 12, in the tools 11 to 16 of the present invention, while the average of the width of the flank wear was about 0.13 mm, the tools 11 to 16 of Comparative Example had short life times due to the progression of flank wear and the occurrence of chipping over a short time.

(67) From the results, it can be seen that the tool of the present invention has excellent chipping resistance and wear resistance under heavy intermittent cutting conditions.

INDUSTRIAL APPLICABILITY

(68) A surface-coated cutting tool of the present invention provides excellent chipping resistance and wear resistance and excellent cutting performance for a long time not only in cutting under heavy intermittent cutting condition of an alloy steel but also in cutting of various workpieces such that it is possible to satisfactorily cope with high performance of a cutting apparatus, save labor of cutting, save energy and lower costs.

REFERENCE SYMBOL LIST

(69) 1: A layer (Cr, Al, M)N

(70) 2: B layer (Ti, Al)N

(71) 3: Tool body

(72) 4: Arc ion plating apparatus

(73) 5: Heater

(74) 6: Rotating table

(75) 7: Cathode electrode TiAl alloy (vapor source)

(76) 8, 10: Anode electrode

(77) 9: Cathode electrode CrAl-M alloy (vapor source)

(78) 11: Reactant gas introduction path

(79) 12: Exhaust gas outlet

(80) 13, 14: Arc power supply

(81) 15: Bias power supply