JP2003340608A - Surface-covered cemented carbide made cutting tool having hard coating layer to exhibit excellent abrasion resistance in high speed heavy cutting condition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-covered cemented carbide made cutting tool having a hard coating layer to exhibit excellent abrasion resistance in a high- speed heavy cutting condition. <P>SOLUTION: The hard coating layer of 1-15 μm made of complex nitride composed of Al, Ti and Cr is formed on the surface of a WC-based cemented carbide substrate or carbonitride titanium-based cermet substrate in the layer thickness direction. This hard coating layer has a component concentration distribution structure arranged to have an Al maximum content point (hereinafter A) and a Ti maximum content point (hereinafter B) alternately repeatedly in predetermined spaces and designed to have Al and Ti contents which vary continuously from the point A to the point B and the point B to the point A. The point A satisfies a composition formula: (Al<SB>1-(</SB>X<SB>+</SB>Z<SB>)</SB>TiXCrZ)N (wherein X is 0.05-0.30 and Z is 0.01-0.15 in atomic ratio). The point B satisfies a composition formula: (Ti<SB>(1-(</SB>Y<SB>+</SB>Z<SB>)</SB>AlYCrZ)N (wherein Y is 0.15-0.40 and Z is 0.01-0.15 in atomic ratio). The space between the point A and the point B which are adjacent to each other is 0.01-0.1 μm. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating layer having excellent high-temperature hardness and heat resistance, as well as high strength and high toughness. The hard coating layer is free from chipping (small chipping) when high-speed cutting with high heat generation and heavy cutting conditions such as high cutting and high feed with high mechanical impact are performed. The present invention relates to a surface-coated cemented carbide cutting tool exhibiting excellent wear resistance (hereinafter referred to as a coated cemented carbide tool). 2. Description of the Related Art In general, a coated carbide tool is a throw-away insert which is detachably attached to a tip of a cutting tool for turning or planing a work material such as steel or cast iron. There are drills and miniature drills used for drilling and cutting, and solid type end mills used for face milling and grooving, shoulder processing, and the like. A throw-away end mill tool or the like that performs cutting in the same manner as an end mill is known. Further, as a coated cemented carbide tool, a substrate made of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or a titanium cermet (hereinafter referred to as TiCY) -based cermet (hereinafter, collectively referred to as a cemented carbide). On the surface of the substrate)
_{Formula: (Ti 1- (M + Z} ) Al M Cr Z) N ( provided that an atomic ratio, M is from .40 to .65, Z is 0.01-0.1
5) is formed by physical vapor deposition of a hard coating layer composed of a composite nitride layer of Ti, Al, and Cr (hereinafter, referred to as (Ti, Al, Cr) N) satisfying the following condition: A coated cemented carbide tool has been proposed, since the (Ti, Al, Cr) N layer constituting the hard coating layer has high-temperature hardness and heat resistance (high-temperature properties) and strength and toughness. It is also known to be used for continuous cutting and intermittent cutting of various steels and cast irons that generate high heat. [0004] Further, the above coated super hard tool is prepared by charging the above super hard substrate into an arc ion plating apparatus which is a kind of physical vapor deposition apparatus schematically shown in FIG. Is heated to a temperature of, for example, 500 ° C., and an anode electrode and Ti-Al having a predetermined composition are mixed.
An arc discharge is generated between the cathode electrode (evaporation source) on which the Cr alloy is set, for example, at a current of 90 A, and a nitrogen gas is introduced as a reaction gas into the apparatus at the same time, for example, a reaction atmosphere of 2 Pa. On the other hand, the above-mentioned (Ti, Al, C) is applied to the surface of the cemented carbide substrate under the condition that a bias voltage of, for example, -100 V is applied to the cemented carbide substrate.
r) It is also known to be manufactured by depositing a hard coating layer consisting of an N layer. [0005] In recent years, the performance of cutting equipment has been remarkably improved, and on the other hand, there has been a strong demand for labor saving, energy saving, and further cost reduction for cutting. However, there is a tendency that cutting under high cutting conditions such as high cutting and high feed is strongly demanded, but in the above-mentioned conventional coated carbide tools, this is required under normal cutting conditions. There is no problem when used, but especially when cutting is performed at high speed and under heavy cutting conditions such as high cutting and high feed with high mechanical impact, the high temperature hardness and heat resistance of the hard coating layer Lack of sex,
In addition, since the strength and toughness are insufficient, the progress of abrasion of the hard coating layer is further promoted, and chipping is likely to occur. Means for Solving the Problems Accordingly, the present inventors have proposed:
In view of the above, in order to develop a coated carbide tool in which the hard coating layer exhibits excellent wear resistance especially under high-speed heavy cutting conditions, attention is paid to the hard coating layer that constitutes the conventional coated carbide tool described above. (A) The (Ti, Al, Cr) N layer constituting the conventional coated carbide tool formed using the arc ion plating apparatus shown in FIG. It has a substantially uniform composition throughout, and thus has a uniform high-temperature hardness and heat resistance, as well as strength and toughness. For example, FIG. 1 (a) is a schematic plan view, and FIG. An arc ion plating apparatus having the structure shown in the figure, that is, a rotary table for mounting a carbide substrate is provided at the center of the apparatus, and a relatively high Al content (Ti
Al-Ti-Cr alloy with low content), Ti-Al- with relatively high Ti content (low Al content) on the other side
An arc ion plating apparatus in which a Cr alloy is opposed to each other as a cathode electrode (evaporation source) is used. A plurality of carbide substrates are mounted in a ring shape along the outer periphery of the rotary table of the apparatus. While rotating the rotary table in a nitrogen atmosphere and rotating the superhard substrate itself for the purpose of equalizing the thickness of the hard coating layer formed by vapor deposition, the cathode electrode (evaporation source) and the anode on both sides of the superhard substrate are rotated. An arc discharge is generated between the electrodes and
When a composite nitride layer of Al, Ti and Cr (hereinafter, referred to as (Al-Ti, Cr) N) is formed on the surface of the cemented carbide substrate, in the resulting (Al-Ti, Cr) N layer,
The cemented carbide substrate arranged in a ring on the turntable is most suitable for the cathode electrode (evaporation source) of the Al-Ti-Cr alloy having a relatively high Al content (low Ti content) on one side. When approached, the highest Al content point is formed in the layer, and the cemented carbide substrate is
The point of highest Ti content is formed in the layer at the point of closest approach to the cathode electrode of a high-content (low-Al content) Ti-Al-Cr alloy. The Al maximum content point and the Ti maximum content point alternately and repeatedly appear at predetermined intervals along with the Al and T contents from the Al maximum content point to the Ti maximum content point and from the Ti maximum content point to the Al maximum content point.
i has a component concentration distribution structure in which the i content continuously changes. (B) In the formation of the (Al-Ti, Cr) N layer having the repeated and continuously changing component concentration distribution structure of (a), Al-Ti- as the cathode electrode (evaporation source) on one side of the opposed arrangement. The Al content in the Cr alloy is relatively higher than the Al content in the conventional Ti-Al-Cr alloy, and the Ti-Al-Cr alloy as the cathode electrode (evaporation source) on the other side is used. In addition to making the Al content relatively lower than the Al content of the conventional Ti-Al-Cr alloy described above, and controlling the rotation speed of the turntable on which the carbide substrate is mounted, The highest Al content point is determined by the composition formula: (Al _{1- (X + Z)} Ti _X Cr _Z ) N (where
In the atomic ratio, X is 0.05 to 0.30, Z is 0.01 to
0.15), and the highest Ti content point is determined by the composition formula:
(Ti _{1- (Y + Z)} Al _Y Cr _Z ) N (However, in atomic ratio, Y
Is 0.15 to 0.40 and Z is 0.01 to 0.15), and the distance in the thickness direction between the adjacent Al maximum content point and Ti maximum content point is 0.01. ~
When the thickness is 0.1 μm, since the Al content is relatively higher in the Al highest content portion than in the conventional (Ti, Al, Cr) N layer, the high-temperature hardness and heat resistance are further improved. (High-temperature properties), while the Ti content is higher at the highest Ti content than in the conventional (Ti, Al, Cr) N layer, so that higher strength and toughness are achieved. With the highest Al content and T
Since the interval between the highest content points is extremely small, the layer as a whole has excellent high-temperature properties while maintaining high strength and high toughness. -Ti, Cr) coated carbide tools consisting of N layers are used for cutting various kinds of steel and cast iron.
In particular, the hard coating layer exhibits excellent wear resistance without chipping even under high-speed heavy cutting conditions involving high heat generation and high mechanical impact.
The research results shown in (a) and (b) above were obtained. The present invention has been made based on the results of the above-mentioned research, and it has been proposed that (Al-T
In a coated cemented carbide tool obtained by physical vapor deposition of a hard coating layer composed of an i, Cr) N layer with a total average layer thickness of 1 to 15 μm,
In the hard coating layer, an Al maximum content point and a Ti maximum content point alternately and repeatedly exist at a predetermined interval along the layer thickness direction, and the Al maximum content point and the Ti maximum content point, From the highest content point to the highest Al content point
And the Ti content has a component concentration distribution structure in which the Al content continuously changes, and the above-mentioned Al maximum content point is determined by the composition formula: (Al _{1-(X + Z)} Ti _X Cr _Z ) N (where atomic In the ratio, X is 0.05 to 0.30, Z is 0.01 to 0.15
), And the highest Ti content point is determined by the composition formula: (Ti
_{1- (Y + Z) Al Y} Cr Z) N ( provided that an atomic ratio, Y is 0.
15 to 0.40, Z represents 0.01 to 0.15), and the interval between the adjacent Al maximum content points and adjacent Ti maximum content points is 0.01 to 0.1 μm. The present invention is characterized by a coated carbide tool in which a hard coating layer exhibits excellent wear resistance under high-speed heavy cutting conditions. Next, the reason why the configuration of the hard coating layer constituting the coated carbide tool of the present invention is limited as described above will be described. (A) Composition of Al maximum content point A at the Al maximum content point of the (Al-Ti, Cr) N layer
The l component improves high-temperature hardness and heat resistance (high-temperature properties), the Ti component improves strength and toughness, and the Cr component further improves heat resistance. Therefore, the Al component and the Cr component The higher the content ratio of steel, the higher the high-temperature characteristics, and the higher the heat resistance, the better the high-speed cutting. However, the X value indicating the ratio of Ti is expressed as a ratio (atomic ratio) in the total amount of Al and Cr. If it is less than 0.05, the proportion of Al becomes relatively too large, and the strength and toughness of the layer itself are inevitably reduced even if Ti maximum content points having high strength and high toughness are present adjacently. As a result, chipping and the like are likely to occur. On the other hand, when the X value indicating the proportion of the Ti component exceeds 0.30, the proportion of Al becomes relatively too small, and desired excellent high-temperature characteristics are secured. It is possible If the Z value indicating the ratio of the Cr component is less than 0.01 in the ratio (atomic ratio) to the total amount of Al and Ti, a desired heat resistance improving effect cannot be obtained, and the Z value is further reduced. Exceeds 0.15, the strength and toughness rapidly decrease.
5 to 0.30 and the Z value as 0.01 to 0.15, respectively. (B) Composition of the highest Ti content point As described above, the highest Al content point has excellent high-temperature characteristics, but is inferior in strength and toughness. To make up for the shortage,
The highest Ti content point, which has a high strength and high toughness due to the high Ti content, is alternately interposed in the thickness direction.
The ratio of the value to the total amount of Ti and Cr (atomic ratio) is 0.4
If it exceeds 0, the proportion of Al becomes relatively too large,
If the desired excellent strength and toughness cannot be ensured, on the other hand, when the Y value is also less than 0.15, the proportion of Ti becomes relatively large, and the desired high-temperature property is obtained at the highest Ti content point. Therefore, the Y value is set to 0.15 to 0.40, and the Z value indicating the proportion of the Cr component is set to 0.01 for the same reason as the above Al maximum content point. ０．１0.15. (C) Interval between the highest Al content point and the highest Ti content point If the interval is less than 0.01 μm, it is difficult to clearly define each point with the above composition, and as a result, the desired High strength, high toughness, and high-temperature properties cannot be ensured. If the distance exceeds 0.1 μm, the disadvantages of each point, that is, if the Al content is the highest, the strength and toughness are insufficient, and the Ti content is high. If it is a point, the lack of high-temperature properties appears locally in the layer, and as a result, chipping easily occurs on the cutting edge or wear progress is promoted. .1
μm. (D) Overall average thickness of the hard coating layer If the thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average thickness exceeds 15 μm, chipping occurs. The average layer thickness was determined to be 1 to 15 μm because it was easier. Next, the coated carbide tool of the present invention will be described in detail with reference to examples. (Example 1) As raw material powders, WC powder, TiC powder, VC powder, and Ta each having an average particle size of 1 to 3 µm
C powder, NbC powder, Cr ₃ C ₂ powder, and Co powder were prepared, and these raw material powders were blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, dried, and then dried under a pressure of 100 MPa. Is pressed into a green compact, and this green compact is sintered in a vacuum of 6 Pa at a temperature of 1400 ° C. for 1 hour, and after sintering, R: 0.03
Honing process, ISO standard, CNMG120
WC-based cemented carbide substrates A1 to A10 having a chip shape of 408 were formed. Further, 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:
Sintered under the condition of holding at 1500 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.03 to obtain a TiC having a chip shape conforming to ISO standard, CNMG120408.
Carbide substrates B1 to B6 made of N-based cermet were formed. Next, each of the above-mentioned super-hard substrates A1 to A10 and B1 to B6 is ultrasonically washed in acetone and dried, and placed on a rotary table in an arc ion plating apparatus shown in FIG. Attached along the outer periphery, one side cathode electrode (evaporation source) Ti-Al-C for forming the highest Ti content point having various component compositions
r-alloy, the other side cathode electrode (evaporation source), Al-Ti-
A Cr alloy is placed opposite to the rotary table, and a metal Ti for bombarding is also mounted. First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less while the inside of the apparatus is heated to 500 ° C. After heating, a DC bias voltage of -1000 V is applied to the carbide substrate rotating while rotating on the rotary table, and the metal T
A current of 100 A flows between i and the anode electrode to generate an arc discharge, thereby cleaning the surface of the super hard substrate with Ti bombardment, and then introducing a nitrogen gas as a reaction gas into the apparatus to form a 2 Pa reaction atmosphere. At the same time, a DC bias voltage of -100 V is applied to the carbide substrate rotating while rotating on the rotary table, and each of the cathode electrodes (the Ti-Al-Cr alloy for forming the Ti highest content point and the Al highest content point) is applied. A current of 100 A is applied between the forming Al-Ti-Cr alloy and the anode electrode to generate an arc discharge, and thus, on the surface of the cemented carbide substrate, along the layer thickness direction, as shown in Tables 3 and 4. The highest Al content point and the highest Ti content point of the target composition are alternately present at the same target intervals shown in Tables 3 and 4, and the highest Al content point and the highest Ti content point from the highest Al content point. Wherein from the Ti maximum content point Al
It has a component concentration distribution structure in which the Al and Ti contents continuously change to the highest content point, respectively.
By depositing a hard coating layer having a target overall layer thickness shown in Table 1 above, a throw-away tip made of a surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention (hereinafter, referred to as the coated cemented carbide tip of the present invention) 16 were each manufactured. For the purpose of comparison, these super-hard substrates A1
A10 and B1 to B6 were ultrasonically cleaned in acetone, dried, and charged into a usual arc ion plating apparatus shown in FIG. 2 to obtain various component compositions as cathode electrodes (evaporation sources). Ti-Al- with
A Cr alloy was mounted, and a metal Ti for bombarding was further mounted. First, the inside of the apparatus was heated to 500 ° C. with a heater while the inside of the apparatus was evacuated and maintained at a vacuum of 0.5 Pa or less. A DC bias voltage of -1000 V is applied to the substrate, and a current of 100 A flows between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the super hard substrate by Ti bombarding. Nitrogen gas is introduced into the apparatus as a reaction gas and 2 Pa
And a DC bias voltage of -100 V is applied to the cemented carbide substrate, and the Ti-A
An arc discharge is generated by flowing a current of 100 A between the l-Cr alloy and the anode electrode.
Table 5 on each surface of ~ A10 and B1 ~ B6
6 (Ti, Al, C) having the target composition and the target layer thickness shown in FIG.
r) By depositing a hard coating layer consisting of an N layer, a conventional surface coated cemented carbide throwaway tip (hereinafter referred to as a conventionally coated cemented carbide tip) 1 as a conventionally coated cemented carbide tool is provided.
~ 16 were each manufactured. Next, the coated carbide tips 1 to 1 according to the present invention will be described.
6 and the conventional coated carbide tips 1 to 16 were screwed to the tip of a tool steel tool with a fixing jig. Work material: JIS SCr420H round bar, Cutting speed: 350 m / min . Notch: 3.8 mm, Feed: 0.32 mm / rev. , Cutting time: 5 minutes, Dry continuous high-speed, high-cut cutting test of alloy steel under the following conditions: Work material: JIS S45C, longitudinally spaced round bar with four longitudinal grooves, Cutting speed: 350 m / min . Cut: 2.8 mm Feed: 0.45 mm / rev. , Cutting time: 10 minutes, Dry intermittent high-speed high-feed cutting test of carbon steel under the following conditions:
Work material: JIS FCD700 round bar, Cutting speed: 350 m / min. Infeed: 3.5 mm Feed: 0.4 mm / rev. A dry continuous high-speed, high-cut cutting test of ductile cast iron was performed under the following conditions: cutting time: 5 minutes, and the flank wear width of the cutting edge was measured in each cutting test. Table 7 shows the measurement results. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7] (Example 2) As raw material powder, average particle size:
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 of (Ti, W) C powder and 1.8 μm of Co
Powders were prepared, and each of these raw material powders was blended into the blending composition shown in Table 8, further added with wax, and ball-mixed in acetone for 24 hours, and dried under reduced pressure.
It is press-molded into various compacts of a predetermined shape at a pressure of 0 MPa, and these compacts are compacted in a vacuum atmosphere of 6 Pa at 7 ° C. /
The temperature is raised to a predetermined temperature in the range of 1370 to 1470 ° C. at a heating rate of 1 minute, held at this temperature for 1 hour, and then sintered under the condition of furnace cooling to obtain a 3 mm diameter of 8 mm, 13 mm, and 26 mm. Kinds of round bar sintered bodies for forming a cemented carbide substrate are formed, and the above three kinds of round bar sintered bodies are subjected to grinding processing in a combination shown in Table 8 to obtain a diameter x length of a cutting edge portion. Is 6mm × 1 each
3mm, 10mm x 22mm, and 20mm x 45m
Carbide substrates (end mills) C-1 to C having dimensions of m and a four-flute square shape with a helix angle of 30 degrees.
-8 were each produced. Next, these super-hard substrates (end mills)
C-1 to C-8 were ultrasonically cleaned in acetone, dried, and charged into the arc ion plating apparatus shown in FIG. 1 under the same conditions as in Example 1 above. Along the direction, the highest Al content point and the highest Ti content point of the target composition shown in Table 9 are alternately repeated at the same target intervals as shown in Table 9, and from the highest Al content point to the highest Ti content point. From the highest Ti content point to the Al
By depositing a hard coating layer having a target total layer thickness as shown in Table 9 having a component concentration distribution structure in which the Al and Ti contents continuously change to the highest content point, End mills made of the surface-coated cemented carbide of the present invention as tools (hereinafter, referred to as the coated carbide end mills of the present invention) 1 to 8 were produced. For the purpose of comparison, the above-mentioned ultra-hard substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone, dried, and then dried in a usual arc ion ion shown in FIG. It was charged into a plating apparatus, and had the target composition and the target layer thickness shown in Table 10 under the same conditions as in Example 1, and had substantially no composition change along the layer thickness direction (Ti, By depositing a hard coating layer composed of an Al, Cr) N layer, end mills made of conventional surface-coated cemented carbide as conventional coated carbide tools (hereinafter, referred to as conventional coated carbide end mills) 1 to 8 were respectively manufactured. . Next, the coated carbide end mill 1 of the present invention will be described.
-8 and the conventional coated carbide end mills 1-8, the coated carbide end mills 1-3 of the present invention and the conventional coated carbide end mills 1-3 are: work material: plane dimension: 100 mm × 250 mm, thickness: 5
0 mm JIS SCM415 plate, Cutting speed: 120 m / min. , Groove depth (cut): 6 mm, table feed: 830 mm / min, dry high-speed high feed groove cutting test of alloy steel, coated carbide end mills 4 to 6 according to the present invention and conventional coated carbide end mills 4 to About 6, work material: plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SUS304 plate, Cutting speed: 140 m / min. , Groove depth (cut): 15 mm, Table feed: 530 mm / min, Dry high-speed high-cut groove cutting test of stainless steel under the following conditions: coated carbide end mills 7, 8 of the present invention and conventional coated carbide end mills 7, For No. 8, Work material: Plane dimensions: 100 mm × 250 mm, thickness: 5
0 mm JIS S55C plate, Cutting speed: 150 m / min. , Groove depth (cut): 10 mm, Table feed: 400 mm / min, Dry high-speed high-feed groove cutting test of carbon steel was performed under the following conditions. 0.1XX where the flank wear width is used as a guide to service life
The cutting groove length up to was measured. The measurement results are shown in Tables 9 and 10, respectively. [Table 8] [Table 9] [Table 10] Example 3 The diameter produced in Example 2 was 8 mm (for forming the cemented carbide substrates C-1 to C-3) and 13 m.
m (for forming the carbide substrate C-4 to C-6), and 26 mm
Using three types of round bar sintered bodies (for forming the cemented carbide substrates C-7 and C-8), the three types of round bar sintered bodies were subjected to grinding to obtain a diameter x length of a groove forming portion. Are 4 mm x 13 mm (carbide substrate D-1 to D-3) and 8 mm x 22 mm (carbide substrate D
-4 to D-6), and dimensions of 16 mm × 45 mm (carbide substrate D-7, D-8), and a twist angle of 30
Substrates (Drills) D-1 to D with 2-Flute Shape
-8 were each produced. Next, these carbide substrates (drills) D-
The cutting blades Nos. 1 to D-8 were honed, ultrasonically cleaned in acetone, dried, and charged in an arc ion plating apparatus also shown in FIG. Under the conditions, the Al maximum content point and the Ti maximum content point of the target composition shown in Table 11 alternately and repeatedly along the layer thickness direction at the target interval shown in Table 11, and from the Al maximum content point. The highest Ti content point, the T
from the highest content point to the highest content point of Al
The surface coating of the present invention as a coated carbide tool according to the present invention is obtained by depositing a hard coating layer having a component concentration distribution structure in which the content continuously changes and having the target total layer thickness also shown in Table 11. Drills made of cemented carbide (hereinafter referred to as coated carbide drills of the present invention) 1 to 8 were produced, respectively. For the purpose of comparison, the cutting edges of the above-mentioned carbide substrates (drills) D-1 to D-8 were honed, ultrasonically washed in acetone, and dried, and then, as shown in FIG.
And having the target composition and the target layer thickness shown in Table 12 under the same conditions as in Example 1 above, and substantially along the layer thickness direction. By depositing a hard coating layer composed of a (Ti, Al, Cr) N layer having no composition change, a drill made of a conventional surface-coated cemented carbide as a conventionally coated carbide tool (hereinafter referred to as a conventional coated carbide drill) 1 to 8 were produced respectively. Next, the coated carbide drills of the present invention 1 to 8
Of the coated carbide drills 1 to 8 of the present invention, the coated carbide drills 1 to 3 of the present invention and the coated carbide drills 1 to 3 of the present invention are: work material: plane dimension: 100 mm × 250 mm, thickness: 5
0 mm JIS S55C plate, Cutting speed: 60 m / min. , Feed: 0.25 mm / rev, hole depth: 12 mm, wet high-speed high-feed drilling cutting test of carbon steel under the conditions, coated carbide drills 4 to 6 of the present invention and conventional coated carbide drills 4 to 6 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS FCD400 plate, Cutting speed: 80 m / min. , Feed: 0.40 mm / rev, hole depth: 24 mm, wet high-speed high-feed drilling cutting test of ductile cast iron, coated carbide drills 7 and 8 of the present invention and conventional coated carbide drills 7 and 8 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS FC250 plate material, Cutting speed: 100 m / min. , Feed: 0.40 mm / rev, Hole depth: 50 mm, Wet high-speed high-feed drilling cutting test of cast iron under the following conditions:
The flank wear width of the cutting edge of the tip was 0.1 mm in all wet drilling tests (using water-soluble cutting oil).
The number of drilling processes up to 3 mm was measured. The measurement results are shown in Tables 11 and 12, respectively. [Table 11] [Table 12] The hard steels constituting the coated carbide tips 1-16, coated carbide end mills 1-8, and coated drills 1-8 of the present invention as the coated carbide tools of the present invention obtained as a result. The composition of the highest Al content point and highest Ti content point in the coating layer, as well as the conventional coated carbide tips 1 to 16 as conventional coated carbide tools and the conventional coated carbide end mills 1 to
8 and the hard coating layers of the conventional coated carbide drills 1 to 8 were measured using an Auger spectroscopic analyzer, and each showed substantially the same composition as the target composition. Further, the interval between the highest Al content point and the highest Ti content point in the hard coating layer of these coated carbide tools of the present invention, and the total layer thickness thereof, and the thickness of the hard coating layer of the conventional coated carbide tool,
When the cross section was measured using a scanning electron microscope, all the values showed substantially the same value as the target value. From the results shown in Tables 3 to 12, it can be seen from the results shown in Tables 3 to 12 that the hard coating layer has, in the thickness direction, the highest Al content point having excellent high-temperature hardness and heat resistance, and Ti having high strength and high toughness. And the highest content point alternately and repeatedly at predetermined intervals, and the highest Al content point and the highest Ti content point,
The coated carbide tool of the present invention having a component concentration distribution structure in which the Al and Ti contents continuously change from the highest content point to the highest Al content point, respectively, is capable of cutting various kinds of steel and cast iron at a high temperature. Even when performed under high cutting conditions and high cutting conditions such as high cutting and high feed with high mechanical impact, the hard coating layer exhibits excellent wear resistance without chipping. On the other hand, the hard coating layer has substantially no composition change along the layer thickness direction (Ti,
In the conventional coated carbide tool comprising an Al, Cr) N layer, under the high-speed heavy cutting conditions, wear progresses rapidly and chipping also occurs due to insufficient high-temperature characteristics of the hard coated layer and insufficient strength and toughness. It is clear that the service life is likely to be reached in a relatively short time because it easily occurs. As described above, the coated cemented carbide tool of the present invention can be used not only for cutting under ordinary conditions, but also for cutting various kinds of steel and cast iron, etc., at high speed heavy cutting accompanied by high heat generation and high mechanical impact. Even when performed under the conditions, since excellent abrasion resistance is exhibited without occurrence of chipping, labor saving and energy saving of cutting work, and further, cost reduction can be sufficiently satisfied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an arc ion plating apparatus used to form a hard coating layer constituting a coated carbide tool of the present invention, (a) is a schematic plan view, (b) Is a schematic front view. FIG. 2 is a schematic explanatory view of a conventional arc ion plating apparatus used for forming a hard coating layer constituting a conventional coated carbide tool.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takashi Koyama             1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture             Mitsubishi Materials Corporation Tsukuba Works (72) Inventor Kazuki Izumi             1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture             Mitsubishi Materials Corporation Tsukuba Works F-term (reference) 3C037 CC02 CC04 CC09 CC11                 3C046 FF03 FF05 FF10 FF11 FF13                       FF16 FF19 FF25                 4K029 AA04 BA58 BC02 BD05 CA04                       DD06 EA01

Claims (1)

1. A hard coating layer comprising a composite nitride layer of Al, Ti and Cr on a surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate with a thickness of 1 to 15 μm.
In a surface-coated cemented carbide cutting tool formed by physical vapor deposition with an overall average layer thickness of, the hard coating layer is arranged such that an Al maximum content point and a Ti maximum content point are spaced at a predetermined interval along the layer thickness direction. Al is present alternately and repeatedly from the highest Al content point to the highest Ti content point, and from the highest Ti content point to the highest Al content point.
And the content of Ti has a component concentration distribution structure in which each of the components continuously changes.
_{1- (X + Z)} Ti _X Cr _Z ) N (where X is 0.
05 to 0.30, Z represents 0.01 to 0.15), and the above-mentioned highest Ti content point is represented by a composition formula: (Ti _{1- (Y + Z)} Al _Y C
r _Z ) N (however, in atomic ratio, Y is 0.15 to 0.4
0 and Z represent 0.01 to 0.15), and the interval between the adjacent Al maximum content points and adjacent Ti maximum content points is 0.01 to 0.1 μm. Surface coated cemented carbide cutting tools with a hard coating layer exhibiting excellent wear resistance under high-speed heavy cutting conditions.