Surface-coated cutting tool in which hard coating layer exhibits exceptional adhesion resistance and anomalous damage resistance

Abstract

A surface-coated cutting tool in which a hard coating layer exhibits exceptional adhesion resistance and anomalous damage resistance is provided. This surface-coated cutting tool includes a tool body composed of a WC based cemented carbide or a TiCN based cermet; and at least one hard coating layer provided on a surface of the tool body, and; 1) the hard coating layer includes at least one complex nitride layer, 2) the complex nitride layer contains 0.001 to 0.030 atom % of chlorine, 3) in the complex nitride layer, an area ratio of longitudinal crystal grains having an aspect ratio equal to or greater than 2 occupying a longitudinal cross section is 50% or more, and 4) a layer thickness of the complex nitride layer is 0.2 μm to 20 μm.

Claims

1. A surface-coated cutting tool comprising: a tool body composed of a cemented carbide comprising WC or a cermet comprising TiCN; and at least one hard coating layer provided on a surface of the tool body, wherein 1) the hard coating layer includes at least one complex nitride layer in which, in a case where the complex nitride layer is expressed by a compositional formula (Ti.sub.(1-x)Zr.sub.xyHf.sub.x(1-y))N, x and y satisfy 0.05≤x≤0.95 and 0<y≤1.0, respectively, where x is a content ratio of a total amount of Zr and Hf to a total amount of Ti, Zr, and Hf, and y is a content ratio of Zr to a total amount of Zr and Hf (here, all of x and y are atomic ratios); 2) the complex nitride layer contains 0.001 to 0.030 atom % of chlorine; 3) in the complex nitride layer, an area ratio of longitudinal crystal grains having an aspect ratio equal to or greater than 2 occupying a longitudinal cross section is 50% or more; and 4) a layer thickness of the complex nitride layer is 0.2 μm or more and 20 μm or less.

2. The surface-coated cutting tool according to claim 1, wherein the complex nitride layer has: 1) a nanoindentation hardness of 2,600 kgf/mm.sup.2 or more in a case where an indentation load is 200 mgf; and 2) a layer thickness of 1 μm or more and 20 μm or less.

3. The surface-coated cutting tool according to claim 1, wherein y satisfies 0<y<1.0.

4. The surface-coated cutting tool according to claim 1, wherein x satisfies 0.08≤x≤0.92, y satisfies 0.1≤y≤1.0, the complex nitride layer contains 0.003 to 0.026 atom % of chlorine, and the complex nitride layer contains no carbon.

5. The surface-coated cutting tool according to claim 1, wherein the complex nitride layer is formed by a method comprising: a first primary nucleus formation step of forming primary nucleus for forming a TiZrN film or a TiZrHfN film, and a second crystal growth step of growing the primary nuclei to form the TiZrN film or the TiZrHfN film, wherein the first primary nucleus formation step comprises: a seed film formation step of forming a ZrN film or a ZrHfN film which are seed films, and an etching step of etching a surface of the ZrN film or the ZrHfN film formed in the seed film formation step to substitute a part of Zr with Ti, and obtaining the primary nucleus of TiZrN or TiZrHfN.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is an overall schematic view of a cross section structure SEM image of a surface-coated layer of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

(2) Next, the coated tool of the invention will be described in more detail with reference to examples.

Examples

(3) As raw material powders, a WC powder, a TiC powder, a ZrC powder, a TaC powder, an NbC powder, a Cr.sub.3C.sub.2 powder, a TiN powder, and a Co powder, all of which had an average grain size of 1 to 3 μm, were prepared, and the raw material powders were mixed in blending compositions shown in Table 1. Wax was further added thereto, and the mixture was blended in acetone by a ball mill for 24 hours and was dried in a vacuum. Thereafter, the resultant material was press-formed into green compacts having predetermined shapes at a pressure of 98 MPa, and the green compacts were sintered in a vacuum at 5 Pa under the condition that the green compacts were held at a predetermined temperature in a range of 1370° C. to 1470° C. for one hour. After the sintering, tool bodies A to C made of WC based cemented carbide with insert shapes according to ISO standard CNMG120408 were respectively manufactured.

(4) In addition, as raw material powders, a TiCN (TiC/TiN=50/50 in terms of mass ratio) powder, a ZrC powder, a TaC powder, an NbC powder, a Mo.sub.2C powder, a WC powder, a Co powder, and an Ni powder, all of which had an average grain size of 0.5 to 2 μm, were prepared, and the raw material powders were mixed in blending compositions shown in Table 2, were subjected to wet mixing by a ball mill for 24 hours, and were dried. Thereafter, the resultant material was press-formed into green compacts at a pressure of 98 MPa, and the green compacts were sintered in a nitrogen atmosphere at 1.3 kPa under the condition that the green compacts were held at a temperature of 1,500° C. for one hour. After the sintering, tool bodies D and E made of TiCN based cermet with insert shapes according to ISO standard CNMG120408 were respectively manufactured.

(5) Subsequently, each of these tool bodies A to E was inserted into a chemical vapor deposition device, and coated tool of the present inventions 1 to 14 were respectively manufactured in the following procedure.

(6) (a) First, regarding the coated tools 6 to 14 of the present inventions, in which the lower layer is provided on the tool body, the Ti compound layer and/or the Al oxide layer as the lower layer having a desired layer thickness shown in Table 4 was vapor-deposited under the conditions shown in Table 3.

(7) (b) Next, the film formation was performed on the tool body of Table 1 or Table 2 shown in tool body symbol, based on Table 6, under the film formation conditions of the formation symbol of TiZrN layer.TiZrHfN layer of the film formation step of the invention shown in Table 5, and the component composition, the aspect ratio, the layer thickness, and the nanoindentation hardness of the TiZrN layer.TiZrHfN layer of the coated tool of the present inventions 1 to 14 obtained are shown in Table 6.

(8) (c) In addition, regarding the coated tool of the present inventions 10 and 11, the upper layer was provided on the TiZrN layer or TiZrHfN layer. Under the conditions shown in Table 3, the Ti compound layer and/or the Al oxide layer as the upper layer having a desired layer thickness shown in Table 6 was vapor-deposited.

(9) In addition, for the purpose of comparison, coated tool of comparative examples 1 to 16 were respectively manufactured in the same procedure as in the coated tool of the present inventions 1 to 14. That is,

(10) (a) Regarding the coated tool of comparative examples 6 to 16 in which the lower layer was provided on the tool body, the Ti compound layer and/or the Al oxide layer as the lower layer having a desired layer thickness shown in Table 4 was vapor-deposited under the conditions shown in Table 3. (The lower layer of coated tool of comparative examples 15 and 16 has the same film formation condition and the same layer thickness as those in the coated tool of the present invention 9 and coated tool of comparative example 9)

(11) (b) Next, the film formation was performed on the tool body of Table 1 or Table 2 shown in tool body symbol, based on Table 7, under the film formation conditions of the formation symbol of TiZrN layer or TiZrHfN layer of the film formation step of the comparative example shown in Table 5, and the component composition, the aspect ratio, the layer thickness, and the nanoindentation hardness of the TiZrN layer.TiZrHfN layer of the coated tool of the Comparative Examples 1 to 16 obtained are shown in Table 7. (Here, in a case where the coated tool of the Comparative Examples 15 and 16 and the coated tool of the present invention 9 are compared to each other, the body and the film formation condition are the same, but the film formation time of the TiZrHfN film is different.)

(12) (c) In addition, regarding the coated tool of the Comparative Examples 10 and 11, the upper layer was provided on the TiZrN layer.TiZrHfN layer. Under the conditions shown in Table 3, the Ti compound layer and/or the Al oxide layer as the upper layer having a desired layer thickness shown in Table 7 was vapor-deposited.

(13) Here, the measurement of the layer thickness of the TiZrN layer and the TiZrHfN layer of the coated tool of the present inventions 1 to 14 and the coated tool of comparative examples 1 to 16 was performed using a scanning electron microscope (magnification of 5000). First, polishing was performed so that a cross section in a direction orthogonal to the tool body at a position separated from a cutting edge by 100 μm on the rake face in the vicinity of the edge. Then, the TiZrN layer and the TiZrHfN layer was observed in a visual field at magnification of 5000 so as to include the position on the rake face separated from the cutting edge by 100 μm, layer thicknesses of five points in the observation visual field were measured and averaged to obtain an average layer thickness, and the results were shown in Tables 6 and 7.

(14) In addition, regarding the average content ratio of Zr, the average content ratio of Hf, and the average content ratio of Ti in all metal elements (that is, Ti, Zr, and Hf) of the TiZrN layer or the TiZrHfN layer in the coated tool of the present inventions 1 to 14 and the coated tool of comparative examples 1 to 16, the measurement was performed on the 10 points of the polished surface described above at a position on the rake face separated from the cutting edge by 90 to 110 μm, by using an electron probe micro-analyzer (EPMA), and an average was obtained.

(15) Then, x and y in the compositional formula (Ti.sub.(1-x)Zr.sub.xyHf.sub.x(1-y))N was obtained from the average content ratio of Zr, the average content ratio of Hf, and the average content ratio of Ti in all metal elements (that is, Ti, Zr, and Hf). A ratio (atom %) of chlorine (Cl) in the TiZrN layer and the TiZrHfN layer to a total amount of Ti, Zr, Hf, N, O, and Cl was measured by the electron probe micro-analyzer.

(16) In addition, regarding the TiZrN layer or the TiZrHfN layer in the coated tool of the present inventions 1 to 14 and the coated tool of comparative examples 1 to 16, longitudinal cross section observation of the TiZrN layer or the TiZrHfN layer in a range including the entire TiZrN layer or TiZrHfN layer was performed on the rake face in the vicinity of the edge over a width of 100 μm from the cutting edge by using a scanning electron microscope (magnification of 5000), the observation was performed from the longitudinal cross section side orthogonal to the surface of the tool body. Regarding each crystal grain, a maximum grain width W of the crystal grain in a direction parallel to the surface of the tool and a maximum grain length L in a direction orthogonal to the surface of the tool were measured, and the aspect ratio was calculated by L/W.

(17) In addition, regarding the nanoindentation hardness of the TiZrN layer or the TiZrHfN layer in the coated tool of the present inventions 1 to 14 and the coated tool of comparative examples 1 to 16, the surface of the TiZrN layer or the TiZrHfN layer was polished, and measurement was performed at an indentation load of 200 mgf by using Berkovich indenter made of diamond, based on ISO 14577, and the results were shown in Tables 6 and 7.

(18) TABLE-US-00001 TABLE 1 Blending composition (% by mass) Type Co TiC ZrC TaC NbC Cr.sub.3C.sub.2 TiN WC Tool A 6.0 0.9 0.5 — 1.5 — 0.9 Balance body B 8.0 1.2 — — — 0.5 1.2 Balance C 10.0 1.5 0.5 0.5 0.5 — 1.5 Balance

(19) TABLE-US-00002 TABLE 2 Blending composition (% by mass) Type Co Ni ZrC TaC NbC Mo.sub.2C WC TiCN Tool D 6.0 3.0 0.5 — 4.0 9.5 25.0 Balance body E 12.0 3.0 — 1.0 4.0 9.5 10.0 Balance

(20) TABLE-US-00003 TABLE 3 Formation conditions (pressure of reaction atmosphere is shown with kPa and Hard coating layer temperature is shown with ° C.) Formation Reaction gas composition Reaction atmosphere Type symbol (volume %) Pressure Temperature TiC layer TiC TiCl.sub.4: 4.2%, CH.sub.4: 8.5%, 7 1020 H.sub.2: balance TiN layer TiN TiCl.sub.4: 4.2%, N.sub.2: 30%, 30 900 H.sub.2: balance 1-TiCN 1-TiCN TiCl.sub.4: 4.2%, N.sub.2: 20%, 7 900 layer CH.sub.3CN: 0.6%, H.sub.2: balance TiCN TiCN TiCl.sub.4: 4.2%, N.sub.2: 20%, 12 1020 layer CH.sub.4: 4%, H.sub.2: balance α-Al.sub.2O.sub.3 α-Al.sub.2O.sub.3 AlCl.sub.3: 2.2%, CO.sub.2: 6.5%, 7 1000 layer HCl: 2.2%, H.sub.2S: 0.2%, H.sub.2: balance κ-Al.sub.2O.sub.3 κ-Al.sub.2O.sub.3 AlCl.sub.3: 3.0%, CO.sub.2: 5.0%, 7 970 layer H.sub.2S: 0.3%, H.sub.2: balance Note) 1-TiCN layer is a TiCN layer having a longitudinal growth crystal structure.

(21) TABLE-US-00004 TABLE 4 Hard coating layer Lower layer (Numerical value at the bottom indicates desired average layer Tool thickness (μm) of each layer.) body First Second Third Type symbol layer layer layer Coated tool 1 A — — — of present 2 B — — — invention, 3 C — — — Coated tool 4 D — — — of compara- 5 E — — — tive example 6 A TiN — — (0.6) 7 B TiN 1-TiCN — (0.2) (8) 8 B TiN 1-TiCN α-Al.sub.2O.sub.3 (0.2) (5) (3) 9 B TiN 1-TiCN κ-Al.sub.2O.sub.3 (0.2) (5) (3) 10 B TiN 1-TiCN — (0.2) (5) 11 B TiN 1-TiCN — (0.2) (3) 12 C TiC TiN TiCN (0.5) .sup. (0.5) (3) 13 D TiN — — (1).sup.  14 E TiN TiC 1-TiCN (0.5) .sup. (0.5) (8)

(22) TABLE-US-00005 TABLE 5 Formation conditions of complex nitride layer (TiZrN layer .Math. TiZrHfN layer) First step (primary nucleus formation step) Formation of ZrN .Math. ZrHfN film formation step complex nitride Gas Gas layer (TiZrN Reaction group A Reaction group B layer .Math. TiZrHfN gas group A Supply time gas group B Supply time layer) composition Supply per one composition Supply per one Formation (volume %) period period (volume %) period period Step symbol ZrCl.sub.4 HfCl.sub.4 HCl H.sub.2 (seconds) (seconds) N.sub.2 (seconds) (seconds) Film A 1.6 0.0 0.20 70.0 4.00 0.25 Balance 4.00 0.25 formation B 0.1 1.4 0.30 70.0 2.50 0.17 Balance 2.50 1.17 step of C 0.1 1.5 0.20 70.0 4.00 0.25 Balance 4.00 0.25 present D 1.6 0.0 0.20 70.0 8.00 0.50 Balance 8.00 0.50 invention E 1.5 0.3 0.35 45.0 4.00 0.25 Balance 4.00 0.25 F 1.2 0.0 0.15 80.0 4.00 0.25 Balance 4.00 0.25 G 1.5 0.3 0.20 45.0 4.00 0.25 Balance 4.00 0.25 Film a 1.5 0.3 0.20 45.0 4.00 0.25 Balance 4.00 0.25 formation b *primary nucleus formation step is not performed step of c 1.6 0.0 0.20 70.0 4.00 0.25 Balance 4.00 0.25 comparative d 1.6 0.0 0.20 70.0 4.00 0.25 Balance 4.00 0.25 example e 1.5 0.3 *0.60 45.0 4.00 0.25 Balance 4.00 0.25 f *TiZrN film is formed by magnetron sputtering method. g *TiZrN film is formed by magnetron sputtering method and held in vacuum at 850° C. for 4 hours. Formation conditions of complex nitride layer (TiZrN layer .Math. TiZrHfN layer) First step (primary nucleus formation step) ZrN .Math. ZrHfN film formation step Phase difference Formation of between complex nitride supply of Etching step layer (TiZrN gas group A Reaction gas layer .Math. TiZrHfN and supply Reaction group C Reaction layer) of gas atmosphere composition Processing atmosphere Formation group B Pressure Temperature (volume %) time Pressure Temperature Step symbol (seconds) (kPa) (° C.) TiCl.sub.4 H.sub.2 (seconds) (kPa) (° C.) Film A 0.25 26 1060 3.0 Balance 120 7 1060 formation B 0.15 33 1060 3.0 Balance 120 7 1060 step of C 0.25 26 1060 3.0 Balance 120 7 1060 present D 0.50 26 1060 3.0 Balance 120 7 1060 invention E 0.25 33 1020 3.0 Balance 240 10 1020 F 0.25 18 1075 3.0 Balance 120 7 1080 G 0.25 33 1020 3.0 Balance 240 10 1020 Film a 0.15 *45 1060 3.0 Balance 240 10 1060 formation b *primary nucleus formation step is not performed step of c 0.25 26 1060 3.0 Balance 120 7 1060 comparative d 0.25 26 1060 3.0 Balance 120 7 1060 example e 0.25 33 1020 3.0 Balance 240 10 1020 f *TiZrN film is formed by magnetron sputtering method. g *TiZrN film is formed by magnetron sputtering method and held in vacuum at 850° C. for 4 hours. Formation of Formation conditions of complex nitride layer (TiZrN layer .Math. TiZrHfN layer) complex nitride Second step (crystal growth step) layer (TiZrN Gas Gas layer .Math. TiZrHfN group D group D layer) composition Supply Supply time Formation (volume %) period per period Step symbol TiCl.sub.4 ZrCl.sub.4 HfCl.sub.4 HCl H.sub.2 (seconds) (seconds) Film A 0.50 1.6 0.0 0.20 70 4.00 0.25 formation B 0.30 0.1 1.0 0.30 45 2.50 0.17 step of C 0.65 0.1 1.5 0.20 70 4.00 0.25 present D 0.25 1.6 0.0 0.20 70 8.00 0.50 invention E 0.50 1.5 0.3 0.35 45 4.00 0.25 F 0.35 1.2 0.0 0.15 80 4.00 0.25 G 0.35 1.5 0.3 0.20 45 4.00 0.25 Film a 0.50 1.5 0.3 0.20 45 4.00 0.25 formation b 0.50 1.6 0.0 0.20 70 4.00 0.25 step of c *1.00 1.6 0.0 0.20 70 4.00 0.25 comparative d *0.10 1.6 0.0 0.20 70 4.00 0.25 example e 0.50 1.5 0.3 *0.60 45 4.00 0.25 f *TiZrN film is formed by magnetron sputtering method. g *TiZrN film is formed by magnetron sputtering method and held in vacuum at 850° C. for 4 hours. Formation conditions of complex nitride layer (TiZrN layer .Math. TiZrHfN layer) Second step (crystal growth step) Phase difference Formation of between complex nitride supply of layer (TiZrN Reaction gas Gas gas group A layer .Math. TiZrHfN group E group E and supply Reaction layer) composition Supply Supply time of gas atmosphere Formation (volume %) period per period group B Pressure Temperature Step symbol N.sub.2 (seconds) (seconds) (seconds) (kPa) (° C.) Film A Balance 4.00 0.25 0.25 26 1060 formation B Balance 2.50 0.17 0.15 33 1060 step of C Balance 4.00 0.25 0.25 26 1060 present D Balance 8.00 0.50 0.50 26 1060 invention E Balance 4.00 0.25 0.25 33 1020 F Balance 4.00 0.25 0.25 18 1075 G Balance 4.00 0.25 0.25 33 1020 Film a Balance 4.00 0.25 0.25 *45 1060 formation b Balance 4.00 0.25 0.25 26 1060 step of c Balance 4.00 0.25 0.25 26 1060 comparative d Balance 4.00 0.25 0.25 26 1060 example e Balance 4.00 0.25 0.25 33 1020 f *TiZrN film is formed by magnetron sputtering method. g *TiZrN film is formed by magnetron sputtering method and held in vacuum at 850° C. for 4 hours. Note1) *indicates that the value is beyond the range of the condition. Note2) Gas composition of the gas group A and the gas group B shows volume % of each gas component, in a case where a total content of the gas group A and the gas group B supplied per one period is 100%. Note3) Gas composition of the gas group D and the gas group E shows volume % of each gas component, in a case where a total content of the gas group D and the gas group E supplied per one period is 100%.

(23) TABLE-US-00006 Hard coating layer Lower layer (Numerical value at the bottom Complex nitride layer (TiZrN layer or TiZrHfN layer) indicates desired average layer Atomic ratio of each metal element in all metal elements Tool thickness (μm) of each layer.) X Y body First Second Third Formation [(Zr + Hf)/(Ti + Zr + Hf)] [Zr/(Zr + Hf)] Type symbol layer layer layer symbol Ti Zr Hf 0.05 ≤ x ≤ 0.95 0 < y ≤ 1.0 Coated 1 A — — — A 0.65 0.35 0.00 0.35 1.00 tool of 2 B — — — B 0.26 0.07 0.67 0.74 0.10 present 3 C — — — C 0.92 0.01 0.07 0.08 0.13 invention 4 D — — — D 0.09 0.91 0.00 0.91 1.00 5 E — — — E 0.85 0.13 0.02 0.15 0.87 6 A TiN — — F 0.63 0.37 0.00 0.37 1.00 (0.6) 7 B TiN 1-TiCN — G 0.49 0.43 0.08 0.51 0.84 (0.2) (8) 8 B TiN 1-TiCN α-Al.sub.2O.sub.3 A 0.64 0.36 0.00 0.36 1.00 (0.2) (5) (3) 9 B TiN 1-TiCN κ-Al.sub.2O.sub.3 B 0.26 0.07 0.67 0.74 0.10 (0.2) (5) (3) 10 B TiN 1-TiCN — C 0.92 0.01 0.07 0.08 0.13 (0.2) (5) 11 B TiN 1-TiCN — D 0.08 0.92 0.00 0.92 1.00 (0.2) (3) 12 C TiC TiN TiCN E 0.85 0.13 0.02 0.15 0.87 (0.5) (0.5) (3) 13 D TiN — — F 0.64 0.36 0.00 0.36 1.00 (1) 14 E TiN TiC 1-TiCN G 0.49 0.43 0.08 0.51 0.84 (0.5) (0.5) (8) Hard coating layer Upper layer Complex nitride layer (TiZrN layer or TiZrHfN layer) (Numerical value at the bottom Area ratio of crystal Nanoindentation indicates desired average layer Tool Cl amount grain structure having Layer hardness (indentation thickness (μm) of each layer.) body Atom % aspect ratio equal to or thickness load of 200 mgf) First Second Type symbol 0.001-0.030 greater than 2 (%) (μm) (kgf/mm.sup.2) layer layer Coated 1 A 0.010 69 5 3530 — — tool of 2 B 0.013 52 12 3220 — — present 3 C 0.010 72 18 3270 — — invention 4 D 0.009 63 12 2640 — — 5 E 0.025 55 12 2650 — — 6 A 0.004 90 2.5 3810 — — 7 B 0.019 60 1.5 2480 — — 8 B 0.009 84 3 3510 — — 9 B 0.012 66 0.5 3290 — — 10 B 0.011 92 3 3270 α-Al.sub.2O.sub.3 — (3) 11 B 0.010 78 3 2630 1-TiCN α-Al.sub.2O.sub.3 (2) (3) 12 C 0.026 63 3 2650 — — 13 D 0.003 86 12 3640 — — 14 E 0.018 62 3 2500 — —

(24) TABLE-US-00007 TABLE 7 Hard coating layer Lower layer (Numerical value at the bottom Complex nitride layer (TiZrN layer .Math. TiZrHfN layer) indicates desired average layer Atomic ratio of each metal element in all metal elements Tool thickness (μm) of each layer.) X Y body First Second Third Formation [(Zr + Hf)/(Ti + Zr + Hf)] [Zr/(Zr + Hf)] Type symbol layer layer layer symbol Ti Zr Hf 0.05 ≤ x ≤ 0.95 0 < y ≤ 1.0 Coated 1 A — — — a 0.22 0.65 0.13 0.78 0.83 tool of 2 B — — — b 0.65 0.35 0.00 0.35 1.00 comparative 3 C — — — c 0.98 0.02 0.00 *0.02 1.00 example 4 D — — — d 0.03 0.97 0.00 *0.97 1.00 5 E — — — e 0.85 0.13 0.02 0.15 0.87 6 A TiN — — f 0.25 0.75 0.00 0.75 1.00 (0.6) 7 B TiN 1-TiCN — g 0.25 0.75 0.00 0.75 1.00 (0.2) (8) 8 B TiN 1-TiCN α-Al.sub.2O.sub.3 a 0.23 0.64 0.13 0.77 0.83 (0.2) (5) (3) 9 B TiN 1-TiCN κ-Al.sub.2O.sub.3 b 0.65 0.35 0.00 0.35 1.00 (0.2) (5) (3) 10 B TiN 1-TiCN — c 0.98 0.02 0.00 *0.02 1.00 (0.2) (5) 11 B TiN 1-TiCN — d 0.03 0.97 0.00 *0.97 1.00 (0.2) (3) 12 C TiC TiN TiCN e 0.84 0.14 0.02 0.16 0.88 (0.5) (0.5) (3) 13 D TiN — — f 0.25 0.75 0.00 0.75 1.00 (1) 14 E TiN TiC 1-TiCN g 0.25 0.75 0.00 0.75 1.00 (0.5) (0.5) (8) 15 B TiN 1-TiCN Al.sub.2O.sub.3 B 0.26 0.07 0.67 0.74 0.10 (0.2) (5) (3) 16 B TiN 1-TiCN Al.sub.2O.sub.3 B 0.26 0.07 0.67 0.74 0.10 (0.2) (5) (3) Hard coating layer Upper layer Complex nitride layer (TiZrN layer .Math. TiZrHfN layer) (Numerical value at the bottom Cl Area ratio of crystal Nanoindentation indicates desired average layer Tool amount grain structure having Layer hardness (indentation thickness (μm) of each layer.) body Atom % aspect ratio equal to or thickness load of 200 mgf) First Second Type symbol 0.001-0.030 greater than 2 (%) (μm) (kgf/mm.sup.2) layer layer Coated 1 A 0.012 *47 6 2720 — — tool of 2 B 0.014 *5 12 3090 — — comparative 3 C 0.010 77 18 2420 — — example 4 D 0.019 52 12 2280 — — 5 E *0.037 64 12 3350 — — 6 A *0.000 *2 2.5 3330 — — 7 B *0.000 71 3 2620 — — 8 B 0.012 *47 3 2730 — — 9 B 0.015 *13 0.5 3190 — — 10 B 0.010 81 3 2450 α-Al.sub.2O.sub.3 — (3) 11 B 0.019 56 3 2260 1-TiCN α-Al.sub.2O.sub.3 (2) (3) 12 C *0.036 66 3 3340 — — 13 D *0.000 *2 3 3330 — — 14 E *0.000 72 3 2710 — — 15 B 0.013 66 *23 3290 — — 16 B 0.012 65 *0.1 Not — — measureable Note) *indicates that the value is beyond the range of the invention shown in Claim 1.

(25) Next, in a state in which each of the various coated tools was clamped to a tip end portion of a cutting tool made of tool steel by a fixing tool, the coated tool of the present inventions 1 to 14 and the coated tool of comparative examples 1 to 16 were subjected to a high-speed feed intermittent cutting test, shown below, a flank wear width of the cutting edge was measured, and presence or absence of the occurrence of adhesion was observed. The results are shown in Table 8.

(26) <<Cutting Conditions A>>

(27) Cutting test: alloy steel dry type high-speed high feed intermittent cutting test

(28) Work material: a round bar of JIS SCM440 with eight longitudinal grooves formed with equal intervals in the longitudinal direction

(29) Cutting speed: 220 m/min

(30) Depth of cut: 2.0 mm

(31) Feed: 0.75 mm/rev.

(32) Cutting time: 5 minutes

(33) <<Cutting Conditions B>>

(34) Cutting test: carbon steel dry type high-speed high feed intermittent cutting test

(35) Work material: a round bar of JIS S45C with two longitudinal grooves in the longitudinal direction

(36) Cutting speed: 275 m/min

(37) Depth of cut: 2.0 mm

(38) Feed: 0.75 mm/rev.

(39) Cutting time: 10 minutes

(40) TABLE-US-00008 TABLE 8 Cutting test result Cutting test result Cutting conditions A Cutting conditions B Cutting conditions A Cutting conditions B Flank Flank Flank Flank maximum maximum maximum maximum Occurrence wear Occurrence wear Occurrence wear Occurrence wear of peeling .Math. width of peeling .Math. width of peeling .Math. width of peeling .Math. width Type chipping (mm) chipping (mm) Type chipping (mm) chipping (mm) Coated 1 None 0.18 None 0.13 Coated 1 **1.9 — **5.5 — tool of 2 None 0.15 None 0.15 tool of 2 **2.2 — **3.9 — present 3 None 0.13 None 0.14 comparative 3 **3.2 — **5.2 — invention 4 None 0.15 None 0.16 examples 4 **2.3 — **6.1 — 5 None 0.16 None 0.19 5 **3.0 — **4.0 — 6 None 0.14 None 0.15 6 **3.7 — **8.8 — 7 None 0.28 None 0.27 7 **2.5 — **4.3 — 8 None 0.12 None 0.09 8 **3.6 — **5.1 — 9 None 0.32 None 0.25 9 **1.9 — **3.4 — 10 None 0.14 None 0.08 10 **2.4 — **5.6 — 11 None 0.13 None 0.10 11 **2.8 — **7.7 — 12 None 0.15 None 0.16 12 **3.0 — **5.3 — 13 None 0.18 None 0.15 13 **3.1 — **6.0 — 14 None 0.29 None 0.30 14 **2.5 — **7.2 — 15 *2.1 — *3.4 — 16 **3.7 — **5.1 — A symbol * in the column of “Occurrence of peeling .Math. chipping” indicates the cutting time till the lifetime of the usage is reached (flank maximum wear width equal to or greater than 0.4 mm) due to the peeling occurred on the hard coating layer, and a symbol ** indicates the cutting time till the lifetime of the usage is reached due to the chipping occurrence on the hard coating layer. A symbol — in the column of “Flank maximum wear width” shows that the flank maximum wear width after the processing or during the lifetime is equal to or greater than 0.4 mm.

(41) As clearly shown from the results of the cutting test of Table 8, the coated tool of the present invention includes the complex nitride layer formed of TiZrN complex nitride or TiZrHfN complex nitride having the desired composition containing chlorine and longitudinal crystal structure, shown in Table 6, as the hard coating layer. Accordingly, during the high-speed high feed intermittent cutting of steel, peeling or chipping does not occur, the maximum flank wear width is also small, and exceptional peeling resistance, chipping resistance, and wear resistance are exhibited.

(42) In contrast, in the coated tool of comparative examples, the complex nitride layer included as the hard coating layer does not satisfy the desired composition or does not have the longitudinal crystal structure. Therefore, the desired properties are not obtained, and the end of lifetime was reached at an early stage due to a progress of wear, occurrence of adhesion, occurrence of chipping, and the like.

INDUSTRIAL APPLICABILITY

(43) As described above, the coated tool of the invention is exceptional in cutting of steel under high-speed high feed intermittent cutting conditions of high efficiency, and exhibits adhesion resistance, chipping resistance, and wear resistance. Therefore, the high performance of the cutting device, labor saving, energy saving, and cost saving of the cutting tool are sufficiently satisfied.