JP2003175405A - Surface-coated cemented-carbide cutting tool having hard coating layer exhibiting excellent heat resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cemented-carbide cutting tool having a hard coating layer exhibiting excellent heat resistance. <P>SOLUTION: The hard coating layer is physically deposited with the whole average layer thickness of 0.8 to 10 μm on the surface of a tungsten carbide- based cemented-carbide substrate or a carbonic nitride titanium-base cermet substrate. The layer is formed by an alternate stack of a first thin layer and a second thin layer, the average layer thickness of which individually range from 0.01 to 0.1 μm. (a) The first thin layer is formed by Ti-Al-Si compound nitride having the composition satisfying the composition formula: (Ti<SB>1-(</SB>X<SB>+</SB>Y<SB>)</SB>AlXSiY)N, and the atom ratio: X: 0.20 to 0.50, Y: 0.15 to 0.30, and texture in which Ti-Al-Si compound nitride particles are enclosed by amorphous silicon nitride having a skeleton structure. (b) The second thin layer is formed by Al-Si compound nitride having the composition satisfying the composition formula: (Al<SB>1-</SB>ZSiZ)N and the atom ratio: Z: 0.15 to 0.30, and texture in which Al-Si compound nitride particles are enclosed by amorphous silicon nitride having a skeleton structure. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating layer having excellent heat resistance, particularly in high-speed cutting of steel or cast iron accompanied by high heat generation. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter, referred to as a coated cemented carbide tool) that suppresses the progress of wear due to overheating and thereby enables a longer service life. 2. Description of the Related Art Generally, a cutting tool includes a throw-away tip which is removably attached to a tip of a cutting tool for turning or planing of a work material such as steel or cast iron. There are drills and miniature drills used for drilling and cutting work materials, and solid type end mills used for face milling, grooving, shoulder processing, etc. of the work material. A throw-away end mill tool or the like which is freely mounted and performs cutting in the same manner as the solid type end mill is known. Further, as a cutting tool, a base made of tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or titanium cermet (hereinafter, referred to as TiCN) -based cermet (hereinafter, collectively referred to as a cemented carbide base) (A) When represented by the composition formula: (Ti ₁ -x Al _x ) N, the atomic ratio X: 0.30 to 0.30 as measured by an Auger spectrometer at the center in the thickness direction. Ti-A satisfying 0.70
1) a lower layer composed of a composite nitride [hereinafter referred to as (Ti, Al) N], and (b) aluminum nitride (hereinafter referred to as AlN).
The upper layer composed of the above (a) and (b)
A coated hard carbide tool obtained by physical vapor deposition of a hard coating layer consisting of 0.8 to 10 μm with a total average layer thickness of 0.8 to 10 μm is also known. The lower layer has excellent high-temperature hardness and heat resistance,
Since the upper layer has excellent thermal conductivity, when it is used for continuous cutting or intermittent cutting of various steels or cast iron, coupled with the excellent heat dissipation exhibited by the upper layer, It is also well known that the lower layer exhibits excellent wear resistance. [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 a physical vapor deposition apparatus schematically shown in FIG. The inside is heated to a temperature of 400 ° C., for example, with an atmosphere of a vacuum of 0.13 Pa, and an anode electrode, a Ti—Al alloy having a predetermined composition and a metal A are heated.
An arc discharge is generated under the conditions of, for example, a voltage of 35 V and a current of 90 A between the cathode electrode (evaporation source) in which each of the electrodes 1 is set, and at the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere. The pressure is set to 1 Pa, and on the other hand, a (Ti, Al) N layer and an upper layer as a lower layer of a hard coating layer are formed on the surface of the super hard substrate under the condition that a bias voltage of, for example, -150 V is applied. As Al
It is also known to be manufactured by depositing an N layer. On the other hand, in recent years, there has been a strong demand for labor saving, energy saving, and further cost reduction in cutting work, and with this, cutting work is accompanied by higher performance of cutting machines. In the conventional coated carbide tools described above, there is no problem if this is used for cutting under ordinary conditions such as steel or cast iron, When used in, the heat generated at the time of cutting becomes extremely high, so that the aluminum constituting the upper layer of the hard coating layer
The heat dissipation effect of the N layer cannot sufficiently satisfactorily prevent the temperature rise of the hard coating layer, and such a temperature rise of the hard coating layer significantly accelerates the progress of wear. It is the present situation. Means for Solving the Problems Accordingly, the present inventors have proposed:
In view of the above, we focused on the hard coating layer of the conventional coated carbide tools described above, and conducted research to develop a hard coating layer that exhibits excellent wear resistance even at elevated temperatures during high-speed cutting. As a result, (a) Si was contained in each of the (Ti, Al) N layer and the AlN layer which are the constituent layers of the hard coating layer of the conventional coated carbide tool, and the composition formula: (Ti
_When expressed by _{1- (X + Y)} Al _X Si _Y ) N, the atomic ratio X:
Ti—Al—Si composite nitride having a composition satisfying 0.20 to 0.50, Y: 0.15 to 0.30 [hereinafter, referred to as “
(Ti, Al, Si) N] layer, and the composition formula:
When represented by (Al _{1 -Z} Si _Z ) N, A having a composition that satisfies Z: 0.15 to 0.30 in atomic ratio by the same transmission electron microscope measurement at the center in the thickness direction.
l-Si composite nitride [hereinafter referred to as (Al, Si) N]
When the (Ti, Al, Si) N layer and the (Al, Si) N layer are formed by, for example, an arc ion plating apparatus, a bias voltage and a reaction atmosphere Is relatively high in a state where the heating temperature of the cemented carbide substrate is kept relatively high, for example, 500 ° C., for example, −3.
Under the conditions of 00V and 10 Pa, these (Ti, Al, Si) N layers and (Al, Si) N layers were observed with a transmission electron microscope to obtain ultrafine crystalline Ti—Al—Si composite nitrides, respectively. Particles [hereinafter, (Ti, A
l, Si) N crystal grains] and ultra-fine crystal Al-
An amorphous silicon nitride (hereinafter, referred to as amorphous SiN) having a skeleton structure (skeleton structure) surrounds Si composite nitride particles [hereinafter, referred to as (Al, Si) N crystal fine particles]. To become a. (B) (Ti, A) in (a) above
The (1, Si) N layer and the (Al, Si) N layer are alternately laminated, and their individual layer thicknesses are 0.0
When the hard coating layer is formed under the condition that the total average layer thickness is 0.8 to 10 μm in a state where the hard coating layer is formed as an extremely thin layer having a thickness of 1 to 0.1 μm, the resulting hard coating layer has the above-mentioned ( Both the (Ti, Al, Si) N layer (hereinafter, referred to as a first thin layer) and the (Al, Si) N layer (hereinafter, referred to as a second thin layer) include the (Ti, Al, Si) N crystal grains and (Al). , Si) N crystal grains and the amorphous SiN having a skeleton structure have extremely excellent heat resistance, so that the heat resistance of the hard coating layer itself is further improved, and the thin film is alternately laminated by the two thin layers. The structure allows the entire hard coating layer to have uniform properties in the thickness direction, and therefore, the coated carbide tool formed with this hard coating layer requires high heat generation, especially for steel and cast iron. Even when used for high-speed cutting, The covering layer exhibits excellent heat resistance and suppresses the progress of abrasion due to overheating of the covering layer itself. Therefore, the abrasion resistance is further improved, and stable cutting performance is exhibited over a long period of time. The research results shown in (a) and (b) above were obtained. The present invention has been made on the basis of the above research results, and has a surface of a superhard substrate of 0.8 to 10 mm.
The hard coating layer physically vapor-deposited with a total average layer thickness of μm is composed of alternately laminated first and second thin layers each having an average layer thickness of 0.01 to 0.1 μm. When the thin layer is represented by the composition formula: (Ti _{1-(X + Y)} Al _X Si _Y ) N, the atomic ratio X: 0.20 as measured by a transmission electron microscope at the center in the thickness direction. ~ 0.50, Y: 0.15 ~ 0.30
Observation by a transmission electron microscope also shows a structure in which amorphous SiN having a skeleton structure (skeleton structure) surrounds (Ti-Al-Si) N crystal grains (Ti, (Al, Si) N, and (b) when the second thin layer is represented by a composition formula: (Al _{1 -Z} Si _Z ) N, the thickness is measured by a transmission electron microscope at the center in the thickness direction. It has a composition satisfying Z: 0.15 to 0.30 in atomic ratio, and is also observed by a transmission electron microscope.
A coated carbide tool having a hard coating layer exhibiting excellent heat resistance, made of (Al, Si) N showing a structure in which amorphous SiN having a skeleton structure surrounds (Al-Si) N crystal grains. It is characterized by the following. Next, in the coated cemented carbide tool of the present invention, the reason why the composition of the first thin layer and the second thin layer constituting the alternate lamination of the hard coating layer and the average layer thickness are limited as described above. I do. (A) Composition of the first thin layer of the hard coating layer In the (Ti, Al, Si) N layer constituting the first thin layer, Ti, Al and a part of Si have high strength and high toughness due to Ti. In addition to forming (Ti-Al-Si) N crystal grains with excellent high-temperature hardness and heat resistance due to Al and further excellent heat resistance due to part of Si, the remaining Si has extremely excellent heat resistance. To form amorphous SiN having a skeleton structure, and therefore, the X value of the composition formula: (Ti _{1-(X + Y)} Al _x Si _Y ) N is an atomic ratio (hereinafter the same) of less than 0.2. Then, the (Ti-Al-S
i) The desired high-temperature hardness and heat resistance cannot be ensured for the N crystal fine particles. Similarly, when the Y value is less than 0.15, formation of an amorphous SiN skeleton structure having particularly excellent heat resistance is insufficient. Therefore, it is difficult to further improve the heat resistance. On the other hand, even when the X value exceeds 0.5, the formation of the skeleton structure is suppressed, and the desired excellent heat resistance is ensured. And Y value is 0.3
If it exceeds 0, the X value is 0.2 to 0.5 and the Y value is 0.15 to 0 for the reason that the strength of the hard coating layer is sharply reduced and chipping easily occurs on the cutting edge. .3
0 was set. (B) Composition of the second thin layer of the hard coating layer In the (Al, Si) N layer constituting the second thin layer, a part of Si has excellent thermal conductivity (heat dissipation). It forms a solid solution in AlN to improve its heat resistance, and forms (Al-Si) N crystal grains having excellent thermal conductivity and heat resistance, and the remaining Si also has extremely excellent heat resistance. Therefore, when the Z value is less than 0.15, the formation of the amorphous SiN having the skeleton structure having particularly excellent heat resistance is also insufficient, and the desired value is obtained. Excellent heat resistance cannot be ensured. On the other hand, when the Z value exceeds 0.30, the excellent thermal conductivity inherent in AlN suddenly decreases, so the Z value is set to 0.15 to 0.15. It was determined to be 0.30. (C) Average thickness of the hard coating layer The average thickness of the first thin layer and the second thin layer constituting the alternate lamination of the hard coating layer is 0.01 to 0.1 μm, respectively. In any thin layer, the average layer thickness is 0.0
When the thickness is less than 1 μm, the properties of each thin layer, that is, high strength and high toughness of the first thin layer, excellent high-temperature hardness, further excellent heat resistance, and excellent heat of the second thin layer The hard coating layer cannot be sufficiently provided with conductivity and further excellent heat resistance. On the other hand, when the average layer thickness exceeds 0.1 μm, the characteristics of the hard coating layer in the thickness direction vary. And the cutting performance becomes uneven over time. Further, the reason why the total average layer thickness of the hard coating layer is set to 0.8 to 10 μm is that when the layer thickness is 0.8 μm, a desired excellent wear resistance cannot be secured for a long period of time. This is because if the layer thickness exceeds 10 μm, chipping and chipping of the cutting edge are likely to occur. 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 the pressure of a
sintering in a vacuum at a temperature of 1400 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.05 to form a WC having a chip shape of ISO standard CNMG120408. Substrates A1 to A10 made of base 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:
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 these super-hard substrates A1 to A10 and B1 to B6 is subjected to ultrasonic cleaning in acetone and dried, for example, as shown in a schematic plan view in FIG. It is mounted on a rotary table in an arc ion plating apparatus shown in a schematic front view, and on the other hand, as a cathode electrode (evaporation source), a first thin layer forming Ti-Al-Si alloy having various component compositions and a second electrode are formed. A for forming 2 thin layers
The l-Si alloy is mounted at a predetermined position in the apparatus, and a metal Ti for bombarding cleaning is also mounted. First, the inside of the apparatus is evacuated and heated to 500 ° C. with a heater while maintaining a vacuum of 0.5 Pa. After that, a DC bias voltage of -1000 V is applied to the cemented carbide substrate rotating on the rotary table to generate an arc discharge between the metal Ti of the cathode electrode and the anode electrode, thereby causing the cemented carbide substrate surface to After washing with Ti bombard, nitrogen gas was introduced as a reaction gas into the apparatus to make a reaction atmosphere of 10 Pa, and a DC bias voltage of -300 V was applied to the super-hard substrate rotating on the rotary table. Electrodes (the first
Arc discharge is generated between the thin-layer forming Ti-Al-Si alloy or the second thin-layer forming Al-Si alloy) and the anode electrode, and the target shown in Table 3 is formed on the surface of the cemented carbide substrate. By depositing the first thin layer and the second thin layer having the composition and the target layer thickness in a combination shown in Table 4 and a hard coating layer having the same number of layers as shown in Table 4,
FIG. 3A is a schematic perspective view and FIG. 3B is a schematic longitudinal sectional view of the present invention. 1-16). For the purpose of comparison, the above-mentioned super-hard substrate A1
A10 and B1 to B6 were each subjected to ultrasonic cleaning in acetone and dried, and then mounted on a normal arc ion plating apparatus also illustrated in FIG. 2, while a cathode electrode (evaporation source) was used. A Ti-Al alloy having various component compositions and metal Al are mounted at predetermined positions in the apparatus, and metal Ti for bombarding is also mounted. First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa. After heating the inside of the apparatus to 500 ° C. with a heater, a DC bias voltage of −1000 V is applied to the superhard substrate to generate an arc discharge between the metal Ti of the cathode electrode and the anode electrode. The surface of the hard substrate was cleaned by Ti bombarding, and nitrogen gas was introduced into the apparatus as a reaction gas to make a reaction atmosphere of 4 Pa.
Under a condition of applying a DC bias voltage of 50 V, an arc discharge is generated between the cathode electrode (the Ti-Al alloy or the metal Al) and the anode electrode, and as shown in Table 5 on the surface of the cemented carbide substrate. By coating a hard coating layer composed of a (Ti, Al) N layer (lower layer) and an AlN layer (upper layer) of the desired target composition and target layer thickness, the conventional surface coating as a conventional coated carbide tool is deposited. Cemented carbide throw-away tips (hereinafter referred to as conventionally coated cemented carbide tips) 1 to 16 were manufactured, respectively. Next, the coated cemented carbide tips 1 to 1 of 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 SCM440 round bar, Cutting speed: 350 m / min . Infeed: 1.5 mm Feed: 0.2 mm / rev. , Cutting time: 10 minutes, Dry high-speed continuous turning test of alloy steel under the following conditions: Work material: JIS S50C, 4 longitudinally-spaced round bars at regular intervals in the longitudinal direction, Cutting speed: 300 m / min. Infeed: 1.5 mm Feed: 0.2 mm / rev. , Cutting time: 5 minutes, Dry high-speed intermittent turning test of carbon steel under the following conditions: Work material: JIS FC300, 4 longitudinally spaced round bars at regular intervals in the longitudinal direction, Cutting speed: 250 m / min . Infeed: 1.5 mm Feed: 0.3 mm / rev. A dry high-speed intermittent turning test of 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 turning test. Table 6 shows the measurement results. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] (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 of (Ti, W) C powder and 1.8 μm of Co
Powders were prepared, and these raw material powders were respectively blended in the composition shown in Table 7, and further added with wax, and ball-mixed in acetone for 24 hours, and dried under reduced pressure.
Press molding at a pressure of 0 MPa into various green compacts of a predetermined shape, and pressing these green compacts in a vacuum atmosphere of 6 Pa at 7 ° C. /
The temperature was raised to a predetermined temperature in the range of 1370 to 1470 ° C. at a heating rate of 1 minute, kept at this temperature for 1 hour, and then sintered under the condition of furnace cooling to obtain a sample having a 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 7 to obtain the diameter × length of the cutting edge portion. Is 6mm × 1 each
3mm, 10mm x 22mm, and 20mm x 45m
Carbide substrate C-1 to C-8 for end mill having dimension of m
Was manufactured respectively. Next, these cemented carbide substrates C-1 to C-8
, Each of which was subjected to ultrasonic cleaning in acetone and dried, was charged into an arc ion plating apparatus also shown in FIGS. 1 (a) and 1 (b), and the surfaces thereof were the same as in Example 1 described above. Under the conditions, the first thin layer and the second thin layer having the target composition and the target layer thickness shown in Table 3 were combined in the combination shown in Table 8 and the hard coating layer having the same number of layers as shown in Table 8 was formed. By vapor deposition, the surface-coated cemented carbide of the present invention as the coated cemented carbide tool of the present invention having a shape shown in a schematic front view in FIG. 4 (a) and a schematic cross-sectional view of the cutting edge portion in FIG. 4 (b). End mills (hereinafter, referred to as coated carbide end mills) 1 to 8 were manufactured. For the purpose of comparison, the cemented carbide substrate C-
Each of 1 to C-8 was ultrasonically cleaned in acetone, dried and charged into a usual arc ion plating apparatus also illustrated in FIG. Under the same conditions as the manufacturing conditions of the coated carbide tips 1 to 16, a hard layer composed of a (Ti, Al) N layer as a lower layer and an AlN layer as an upper layer having a target composition and a target layer thickness shown in Table 9 By depositing a coating layer, end mills 1 to 8 of conventional surface-coated cemented carbide (hereinafter, referred to as conventional coated carbide end mills) as conventional coated carbide tools were manufactured, respectively. 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 SNCM439 plate material, Cutting speed: 160 m / min. , Groove depth (cut): 3 mm, Table feed: 650 mm / min, Dry high-speed grooving test of alloy steel, coated carbide end mills 4 to 6 of the present invention and conventional coated carbide end mills 4 to 6 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
JIS FC300 plate material of 0 mm, Cutting speed: 180 m / min. , Groove depth (cut): 5 mm, table feed: 600 mm / min., Dry high-speed groove cutting test of cast iron, coated carbide end mills 7 and 8 of the present invention and conventional coated carbide end mills 7 and 8 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SUS304 plate, Cutting speed: 60 m / min. , Groove depth (cut): 10 mm, table feed: 150 mm / min., Dry stainless steel high-speed grooving test under the following conditions. The cut groove length up to 0.1 mm, which is a standard for the service life, was measured. The measurement results are shown in Tables 8 and 9, respectively. [Table 7] [Table 8] [Table 9] 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 super-hard substrate C-4 to C-6), and 26 mm
Using the 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 the diameter × length of the groove forming portion. Are 4 mm × 13 mm (carbide substrate D-1 to D-3) and 8 mm × 22 mm (carbide substrate D
-4 to D-6), and a carbide substrate D- for a drill having dimensions of 16 mm × 45 mm (carbide substrates D-7 and D-8).
1 to D-8 were produced respectively. Next, these super-hard substrates D-1 to D-8
Was ultrasonically washed in acetone and dried, and then charged into an arc ion plating apparatus also shown in FIGS. 1A and 1B, and the surface of the super-hard substrate was placed on the surface of Example 1 described above. Under the same conditions as above, the first thin layer and the second thin layer having the target composition and the target layer thickness shown in Table 3 were combined in the combination shown in Table 10 and the same number of layers as shown in Table 10 were used. By depositing a coating layer, the surface coating of the present invention as a coated carbide tool of the present invention having a shape shown in a schematic front view in FIG. 5A and a schematic cross-sectional view of a groove forming portion in FIG. Drills made of cemented carbide (hereinafter referred to as coated carbide drills of the present invention) 1 to 8 were produced. For the purpose of comparison, the above-mentioned carbide substrate D-
Each of 1 to D-8 was ultrasonically cleaned in acetone, dried and charged into a usual arc ion plating apparatus also illustrated in FIG. Under the same manufacturing conditions as the coated carbide tips 1 to 16, a hard layer composed of a (Ti, Al) N layer as a lower layer and an AlN layer as an upper layer having a target composition and a target layer thickness shown in Table 11 By depositing a coating layer, a drill made of a conventional surface-coated cemented carbide as a conventionally coated cemented carbide tool (hereinafter, referred to as a conventional coated carbide drill) 1
8 were each produced. Next, the above-mentioned coated carbide drills 1 to 8 according to the present invention.
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 S50C plate, Cutting speed: 140 m / min. , Feed: 0.18 mm / rev, Wet high-speed drilling test of carbon steel under the following conditions: coated carbide drills of the present invention 4-6 and conventional coated carbide drills 4-
About 6, work material: plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SCM440 plate, Cutting speed: 100 m / min. , Feed: 0.18 mm / rev, Wet high-speed drilling test of alloy steel under the following conditions: coated carbide drills 7 and 8 according to the present invention and conventional coated carbide drills 7 and 8
About 8, work material: plane dimension: 100 mm x 250 mm, thickness: 5
0 mm JIS FC250 plate, Cutting speed: 90 m / min. , Feed: 0.27mm / rev, Wet high-speed drilling cutting test of cast iron under the following conditions, and any wet high-speed drilling cutting test (both tests use water-soluble cutting oil). Was measured until the flank wear width reached 0.3 mm. The measurement results are shown in Tables 10 and 11, respectively. [Table 10] [Table 11] The resulting coated carbide tips 1-16, coated carbide end mills 1-8, and coated carbide drill 1 of the present invention as the resulting coated carbide tools of the present invention.
-8, the composition, the structure, and the layer thickness of the first thin layer and the second thin layer constituting the hard coating layer, the conventional coated carbide tips 1-16 as the conventional coated carbide tool, and the conventional coated carbide end mill 1. -8, and the composition, structure, and structure of the lower layer and the upper layer, which are constituent layers of the hard coating layer of the conventionally coated carbide drills 1-8.
And the layer thickness was measured at the center in the thickness direction of each constituent layer using a transmission electron microscope. As for the composition and the layer thickness, they were substantially the same as the target compositions and the target layer thicknesses in Tables 3 to 11. The composition and the average layer thickness (compared to the average value of measurement at five arbitrary points) are shown. Further, with respect to the microstructure, in the coated carbide tool of the present invention, the first thin layer is (Ti-Al-
A structure in which amorphous SiN having a skeleton structure (skeleton structure) surrounds Si) N crystal grains, and a second thin layer is formed of (Al-S).
i) Amorphous SiN having skeleton structure with N crystal fine particles
The conventional coated cemented carbide tool showed a structure in which the lower layer was composed of crystalline (Ti, Al) N and the upper layer was composed of crystalline AlN. From the results shown in Tables 3 to 11, the coated carbide tools of the present invention, in which the hard coating layer is composed of alternating multiple layers of the first thin layer and the second thin layer, are all steel or cast iron. Even if the cutting process is performed at a high speed with high heat generation, the progress of abrasion is remarkably suppressed even though the hard coating layer is heated to a high temperature by the excellent heat resistance of the hard coating layer, and the cutting edge is not chipped. While exhibiting excellent abrasion resistance without occurrence of chipping or the like, the substantially hard coating layer substantially forms the lower layer (Ti, A
l) In conventional coated carbide tools comprising an N layer and an AlN layer as an upper layer, wear progresses in any case because the hard coating layer which has been heated at high heat and raised in temperature during high-speed cutting does not have sufficient heat resistance. Is remarkably accelerated, and the service life is apparently shortened in a relatively short time. As described above, the coated carbide tool of the present invention exerts excellent wear resistance not only in cutting under various conditions such as steel and cast iron but also in high-speed cutting. Therefore, it is possible to satisfactorily cope with the labor saving and energy saving of the cutting process and the cost reduction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an arc ion plating apparatus used for forming a hard coating layer of a coated carbide tool according to the present invention, wherein (a) is a schematic plan view and (b) is a schematic front view. is there. FIG. 2 is a schematic explanatory view of an arc ion plating apparatus used for forming a hard coating layer of a conventional coated carbide tool. FIG. 3A is a schematic perspective view of a coated carbide tip, and FIG.
1 is a schematic vertical sectional view of a coated carbide tip. FIG. 4 (a) is a schematic front view of a coated carbide end mill,
(B) is a schematic transverse sectional view of the cutting blade portion. FIG. 5A 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.

Continuation of front page    (72) Inventor Yusuke Tanaka             179 Kanegasaki Nishi-Oike, Uozumi Town, Akashi City, Hyogo Prefecture             1. MMC Kobelcourt Co., Ltd.             Inside F term (reference) 3C046 FF03 FF05 FF10 FF16 FF19                       FF25                 4K029 BA58 BB02 BB07 BB10 BC10                       BD05 CA04 EA01

Claims (1)

Claims: 1. A tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate has a surface of 0.8 to 10%.
The hard coating layer physically deposited with a total average layer thickness of μm is composed of alternately laminated first and second thin layers each having an average layer thickness of 0.01 to 0.1 μm; The thin layer is formed by the composition formula: (Ti _{1- (X + Y)} Al _X S
i _Y ) When represented by N, the atomic ratio X: 0.20 to 0.5 as measured by a transmission electron microscope at the center in the thickness direction.
0, Y: has a composition satisfying 0.15 to 0.30, and is also observed by a transmission electron microscope.
T showing a structure in which i-Al-Si composite nitride particles are surrounded by amorphous silicon nitride having a skeleton structure (skeleton structure)
(b) When the second thin layer is represented by a composition formula: (Al _{1 -Z} Si _Z ) N, it is determined by a transmission electron microscope at the center in the thickness direction. According to the measurement, the atomic ratio has a composition satisfying Z: 0.15 to 0.30, and the ultrafine crystalline Al-Si composite nitride particles are also observed by a transmission electron microscope to have a skeleton structure (skeleton structure). (1) A cutting tool made of a surface-coated cemented carbide in which a hard coating layer exhibits excellent heat resistance, wherein the cutting tool is made of an Al-Si composite nitride exhibiting a structure surrounded by amorphous silicon nitride.