JP2002254211A - Cutting tool made of surface-coated cemented carbide exerting excellent wear resistance in cutting at high speed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool made of surface-coated cemented carbide exerting excellent wear resistance in cutting at a high speed. SOLUTION: On the surface of a cemented carbide tool base, which is made of a sintered body of green compacts having a mixed composition 4-12% of Co: 5-30% of one or more than two kinds among TiC, NbC, TaC, (Nb, Ta)C, and (Ti, W)C: and WC for the remaining by a mass percentage, a hard coated layer composed of (a) a physically vapor-deposited (Ti, Al)N layer having an average layer thickness of 0.5-10 μm and also satisfying a composition formula: (Ti1- XAlX)N (here, X is 0.2-0.6 by an atomic percentage), as an inner side layer, and (b) an Al2 O3 layer having an average layer thickness of 0.1-5 μm chemically vapor-deposited under a medium temperature, as an exterior side layer, is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tungsten carbide-based cemented carbide substrate (hereinafter referred to as a cemented carbide substrate) having excellent high-temperature strength and a hard coating layer having excellent high-temperature strength and high-temperature hardness. Therefore, when used for high-speed cutting of steel or cast iron with high heat generation, it relates to cutting tools made of surface-coated cemented carbide (hereinafter referred to as coated carbide tools) that exhibit excellent wear resistance. is there.

[0002]

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

[0003] Further, a certain coated cemented carbide tool among the various cutting tools described above uses, for example, an arc ion plating apparatus which is a kind of physical vapor deposition apparatus schematically shown in FIG. In a state where the inside of the apparatus is heated to a temperature of 500 ° C. by, for example, setting the atmosphere in a vacuum of 3 Pa with a heater, the anode electrode and the cathode electrode (evaporation source) on which an alloy having a predetermined component composition is set are heated. For example, an arc discharge is generated under the conditions of, for example, a voltage of 35 V and a current of 100 A, and at the same time, a nitrogen gas or the like is introduced as a reaction gas into the apparatus. On the other hand, as a substrate, for example, a tungsten carbide (hereinafter referred to as WC) -based carbide An alloy substrate (hereinafter, referred to as a cemented carbide substrate) is mounted on the surface of the cemented carbide substrate under the condition that a bias voltage of, for example, -100 V is applied. It is also known that are produced by depositing a hard coating layer made of a nitride layer of the components of the alloy constituting the.

Further, a coated carbide tool is prepared by mounting the above-mentioned carbide substrate in an ordinary chemical vapor deposition apparatus, and 950 to 1 in the apparatus.
When heated to a predetermined temperature in the range of 050 ° C., and the hard coating layer to be formed as a reaction gas is TiCl ₄ , N ₂ , CH ₃ C, for example, if it is a titanium carbonitride layer
A mixed gas of N (or CH ₄ ) and H ₂ , or AlCl ₃ , CO ₂ , HCl, H ₂ S in the case of an aluminum oxide (shown by Al ₂ O ₃ ) layer having an α-type or κ-type crystal structure ,
And introducing a mixed gas of H _2, it is where, also known to be produced by the hard coating layer on a surface of the carbide substrate by vapor phase decomposition gas reaction formed by evaporation.

[0005]

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 has been performed at high speeds in conjunction with high performance of cutting machines. Although there is no problem with the various types of coated carbide tools that have been proposed in the past when they are used for cutting under ordinary conditions such as steel or cast iron, this is not a problem. When used under the conditions, not only the high heat generated during the cutting process causes not only the thermoplastic deformation to cause uneven wear on the cutting edge portion but also the remarkable decrease in the high-temperature hardness of the cutting edge portion. At the present, wear progress is accelerated, and as a result, the service life is reached in a relatively short time.

[0006]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoints, research was conducted to develop coated carbide tools having excellent high-temperature strength and high-temperature hardness. (A) As a raw material powder, tungsten carbide (hereinafter referred to as WC)
) Powder, titanium carbide (hereinafter, referred to as TiC) powder,
Niobium carbide (hereinafter referred to as NbC) powder, tantalum carbide
Powder (hereinafter referred to as TaC), composite carbide of Nb and Ta [hereinafter referred to as (Nb, Ta) C] powder, composite carbide of Ti and W [hereinafter referred to as (Ti, W) C] powder, and Using a Co powder, the composition of the composition is determined as follows: Co: 4 to 12%, one or more of TiC, NbC, TaC, (Nb, Ta) C, and (Ti, W) C: 5 to 30
%, WC: the remaining sintered compact of TiC and Nb which is present as a hard phase in addition to WC
C, TaC, (Nb, Ta) C, and (Ti, W) C
To have higher high temperature strength.

[0007] (b) the sintered body of (a) a substrate (cemented carbide substrate) was formed using a physical vapor deposition method to the surface as a hard coating layer, the composition formula: (Ti _1-X Al _X ) N (where X is 0.2-0.6 in atomic ratio) (Ti,
The Al) N layer has excellent high-temperature strength.

(C) The physical vapor deposition (Ti, A
l) Although the N layer has excellent high-temperature strength as described above, it does not maintain sufficient high-temperature hardness under high temperatures during high-speed cutting, but this is used as an inner layer, and As the outer layer, the reaction gas atmosphere temperature is adjusted to a normal 950 temperature.
When an Al ₂ O ₃ layer having an α-type or κ-type crystal structure is formed by a medium temperature chemical vapor deposition method at a temperature lower than 750 ° C. to 850 ° C. as compared with −1050 ° C., the Al ₂ O ₃ layer has high high-temperature hardness. Therefore, the (Ti, Al) N layer of the inner layer and the A layer of the outer layer
l ₂ hard coating layer comprising a lamination of the O ₃ layer to become comprises a high-temperature strength and high-temperature hardness with excellent.

(D) Accordingly, the coated carbide tool obtained by forming the hard coating layers of (b) and (c) on the surface of the cemented carbide substrate of (a) is characterized in that the cemented carbide substrate has an excellent high temperature. The inner layer of the physical vapor-deposited (Ti, Al) N layer and the outer layer of the medium-temperature chemical vapor-deposited Al ₂ O ₃ layer having strength (heat-resistant plastic deformability) and constituting the hard coating layer have excellent high-temperature strength and high temperature. Due to its hardness, even when it is used for high-speed cutting with high heat generation, uneven wear is remarkably suppressed and excellent wear resistance is exhibited over a long period of time. The research results shown in (a) to (d) above were obtained.

The present invention has been made on the basis of the above-mentioned research results, wherein Co: 4 to 12%, among TiC, NbC, TaC, (Nb, Ta) C and (Ti, W) C One or more of the following: 5-3
0%, WC: on the surface of a cemented carbide substrate composed of a sintered compact of a compact having a composition consisting of:
It has an average layer thickness of 0.5 to 10 μm and has a composition formula: (T
i _1-x Al _x ) N (where X is 0.2 to 0.
6, a physical vapor deposition (Ti, Al) N layer satisfying
(B) High-speed cutting by forming, as an outer layer, a medium-temperature chemical vapor deposition Al ₂ O ₃ layer having an average layer thickness of 0.1 to 5 μm, and a hard coating layer composed of the above (a) and (b). It is characterized by coated carbide tools exhibiting excellent wear resistance.

Next, in the coated cemented carbide tool according to the present invention, the composition of the cemented carbide substrate (sintered body), the X value of the inner layer of the hard coating layer, and the X value of the inner layer and the outer layer. The reason why the average layer thickness is limited as described above will be described. (1) Composition of Carbide Substrate (a) Co The Co component has the effect of improving the sinterability and improving the room-temperature strength of the sintered body. However, if the desired improvement effect is not obtained, on the other hand, if the ratio exceeds 12%, the high-temperature strength of the sintered body tends to decrease, and plastic deformation tends to occur in the cutting edge portion, and as a result, the progress of wear progress is accelerated. Since the unbalanced wear causing the problem occurs in the cutting edge portion, the ratio is set to 4 to 12%.

(B) TiC, NbC, TaC, (Nb,
Ta) C and (Ti, W) C These components, together with WC, form a hard phase to improve the high-temperature strength of the sintered body, thereby suppressing the occurrence of thermoplastic deformation at the cutting edge. If the ratio is less than 5%, the desired high-temperature strength improvement effect cannot be obtained, while if the ratio exceeds 30%, the normal-temperature strength of the sintered body decreases rapidly, and Since chipping (small chipping) easily occurs, the ratio is set to 5 to 30%.

(2) X value of the inner layer of the hard coating layer Al in the (Ti, Al) N layer imparts heat resistance to TiN having high toughness (high strength) and has excellent high-temperature strength. Therefore, if the X value of the composition formula (Ti _1-x Al _x ) N is less than 0.2, a desired excellent high-temperature strength cannot be secured. When the value exceeds 0.6, embrittlement occurs and high-temperature strength decreases, so that the X value is set to 0.2 to 0.2.
It was determined to be 0.6.

(3) Average thickness of hard coating layer Physical vapor deposition (Ti, A
l) The average layer thickness of the N layer is 0.5 to 10 μm
If the average layer thickness is less than 0.5 μm, the desired high-temperature strength cannot be imparted to the hard coating layer, and as a result, chipping tends to occur in the cutting edge portion, while the layer thickness is 10 μm.
Above, the wear progress at the cutting edge becomes localized,
This is because the service life is shortened. Also, medium temperature chemical vapor deposition Al ₂ which also constitutes the outer layer
The reason why the average layer thickness of the O ₃ layer is 0.1 to 5 μm is that if the layer thickness is less than 0.1 μm, the desired high-temperature hardness cannot be imparted to the hard coating layer. This is because the desired effect of improving the properties cannot be obtained, while if the layer thickness exceeds 5 μm, chipping is likely to occur at the cutting edge.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. (Example 1) As raw material powders, medium coarse WC powder having an average particle size of 5.5 µm, fine WC powder having the same 0.8 µm,
1.5 μm TiC powder, 1.3 μm TaC powder, 1.2 μm NbC powder, 1.0 μm (T
a, Nb) C [TaC / NbC = 50/5 by mass ratio]
0] powder, (Ti, W) C of the same 1.0 μm [by mass ratio,
TiC / WC = 70/30] powder and 1.8 μm
Co powders were prepared, each of these raw material powders was blended in the blending composition shown in Table 1, wax was added thereto, and the mixture was ball-milled in acetone for 24 hours, and dried under reduced pressure. These compacts are press-formed into powder 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, sintered under furnace cooling conditions, and after sintering, R: 0 was added to the cutting edge. By performing honing processing of .05, chip cemented carbide substrates A to I each having the shape of ISO standard CNMG120408 were manufactured.

Next, these chip cemented carbide substrates A to I
Was washed ultrasonically in acetone and dried, and each was charged into a usual arc ion plating apparatus illustrated in FIG. 1, while Ti— having various compositions was used as a cathode electrode (evaporation source). An Al alloy, and a metal Ti for bombardment of the surface of a super-hard substrate were mounted, and the inside of the apparatus was evacuated.
While maintaining a vacuum of 5 Pa, the inside of the apparatus is heated to 50 Pa by a heater.
After heating to 0 ° C., Ar gas was introduced into the apparatus to
In an Ar atmosphere of Pa, in this state, -8
00V bias voltage to apply A
r Gas bombardment cleaning, and further lowering the bias voltage applied to the cemented carbide substrate to −100 V to generate an arc discharge between the metal Ti of the cathode electrode and the anode electrode, thereby reducing the surface of the cemented carbide substrate. (In this case, the surface portion of the cemented carbide substrate has a very thin thickness of 0.05 μm or less, such as a Ti thin layer or a titanium carbide thin layer, and depending on the atmosphere of the gas introduced into the apparatus, a titanium nitride layer or a carbon thin layer. (A titanium nitride layer may be formed in some cases.) Then, the inside of the apparatus is set to an atmosphere of a nitrogen gas (reaction gas) of 2.5 Pa, while the bias voltage applied to the cemented carbide substrate is kept at -1.
00V, the Ti-
The target composition (X value) and the target layer thickness (Ti, A) shown in Table 2 were applied to the respective surfaces of the cemented carbide substrate by the arc discharge generated between the Al alloy and the anode electrode.
The l) N layer was deposited as an inner layer of the hard coating layer, the further surface of the inner layer, using conventional chemical vapor deposition apparatus, the reaction gas composition, in _{volume%, AlCl 3: 2%,} CO 2: 3 %, H ₂ S: 0.3%, HCl: 1%, H ₂ : balance, and a normal reaction gas composition, and the reaction atmosphere pressure is the same as the normal reaction pressure of 7 KPa. 950 to 105 which is the ambient temperature
The Al ₂ O ₃ layer having the target layer thickness also shown in Table 2 under the medium temperature chemical vapor deposition conditions of 850 ° C. (α-type crystal structure) and 800 ° C. (κ-type crystal structure) relatively lower than 0 ° C. Is formed as an outer layer of the hard coating layer, thereby obtaining FIG.
In a schematic perspective view, a throw-away tip made of a surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention having a shape shown in a schematic longitudinal sectional view of FIG. 1) to 9).

For the purpose of comparison, as shown in Table 3, the hard coating layer was formed under the same conditions except that the Al ₂ O ₃ layer was not formed under the above-mentioned medium temperature chemical vapor deposition conditions.
Comparative surface coated cemented carbide throwaway tips (hereinafter referred to as comparative coated cemented carbide tips) 1 to 9 as comparative coated cemented carbide tools consisting only of N layers were produced, respectively.

For the hard coating layers of the coated super hard tips 1 to 9 of the present invention and the comparative coated super hard tips 1 to 9 obtained as described above, the composition at the center of the thickness section of each of the constituent layers was determined by Auger spectroscopy. Measure using an analyzer,
When the thickness was measured in cross section using a scanning electron microscope, all the values showed substantially the same values as the target composition and the target layer thickness shown in Tables 2 and 3.

Next, the coated carbide tips 1 to 9 according to the present invention will be described.
And in the state where each of the comparative coated carbide tips 1 to 9 is screwed to the tip of the tool steel tool with a fixing jig, the coated carbide tips 1 to 5 of the present invention and the comparative coated carbide tips 1 to 9 are prepared.
For No. 5, Work material: JIS SCM440 round bar, Cutting speed: 355 m / min. , Cut: 1.2 mm, feed: 0.2 mm / rev. Cutting time: 5 minutes, dry high-speed continuous turning test of alloy steel, and coated carbide tips 6-9 of the present invention and comparative coated carbide tips 6-9, work material: JIS SNCM439 Round bar with four longitudinal grooves at equal intervals in the longitudinal direction, Cutting speed: 200 m / min. Infeed: 2.0 mm Feed: 0.3 mm / rev. A dry high-speed intermittent turning test of the alloy steel was performed under the conditions of cutting time: 10 minutes, and the flank wear width of the cutting edge portion was measured in each turning test. The measurement results are shown in Tables 2 and 3.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

(Example 2) Using the same raw material powders as used in Example 1, these raw material powders were similarly blended in the composition shown in Table 1, and then under the same conditions as in Example 1. , Mixed, press-molded into a green compact, and sintered to form three types of round bar sintered bodies having a diameter of 8 mm, 13 mm, and 26 mm for forming a carbide substrate.
The diameter x length of the cutting edge portion is 6 mm x 13 m in each of the combinations shown in Table 4 by grinding from various kinds of round bar sintered bodies.
m, 10 mm x 22 mm, and 20 mm x 45 mm were manufactured respectively.

Next, these end mill super hard substrates A to
The surface of I was honed, ultrasonically cleaned in acetone, dried and charged in a usual arc ion plating apparatus also illustrated in FIG. 1 under the same conditions as in Example 1 above. Then, a physical vapor deposition (Ti, Al) N layer having a target composition (X value) and a target layer thickness shown in Table 4 is deposited as an inner layer of a hard coating layer on each surface of the superhard substrate. By forming a medium-temperature chemical vapor deposition Al ₂ O ₃ layer having a target layer thickness also shown in Table 4 as an outer layer of the hard coating layer on the surface of the inner layer, a schematic front view in FIG. ) End mills (hereinafter referred to as coated carbide end mills) 1 to 9 of the surface coated cemented carbide alloy of the present invention as coated carbide tools of the present invention having the shape shown in the schematic cross-sectional view of the cutting edge portion. Manufactured.

For the purpose of comparison, as shown in Table 5, under the same conditions except that the Al ₂ O ₃ layer was not formed under the above-mentioned medium temperature chemical vapor deposition conditions, the hard coating layer was subjected to physical vapor deposition (T
End mills (hereinafter referred to as comparative coated carbide end mills) 1 to 9 made of comparative surface coated cemented carbide as comparative coated carbide tools consisting only of the (i, Al) N layer were produced, respectively.

With respect to the hard coating layers of the coated carbide end mills 1 to 9 of the present invention and the comparative coated carbide end mills 1 to 9 obtained as a result, the composition at the center of the thickness section of each of the constituent layers was measured by Auger spectroscopy. The thickness was measured using an analyzer, and the thickness was measured in cross section using a scanning electron microscope. As a result, the thickness was substantially the same as the target composition and target layer thickness shown in Tables 4 and 5. .

Next, the coated carbide end mill 1 of the present invention will be described.
-9 and the comparative coated carbide end mills 1-9, the coated carbide end mills 1-3 of the present invention and the comparative coated carbide end mills 1-3 are: Work material: plane dimension: 100 mm × 250 mm, thickness: 5
0 mm JIS S45C plate, Cutting speed: 230 m / min. Groove depth (cut): 2.5 mm, Table feed: 3000 mm / min, wet high-speed groove cutting test of carbon steel (using water-soluble cutting oil), and coated carbide end mill of the present invention 4 to 6 For the coated coated carbide end mills 4 to 6, work material: plane dimension: 100 mm x 250 mm, thickness: 5
0 mm JIS SCM440 plate, Cutting speed: 235 m / min. , Groove depth (cut): 3.5 mm, Table feed: 2000 mm / min, dry high-speed grooving test of alloy steel, and coated carbide end mills 7 to 9 of the present invention and comparative coated carbide end mill For 7 to 9, Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS FC250 plate material, Cutting speed: 290 m / min. , Groove depth (cut): 5 mm, Table feed: 3000 mm / min, wet iron high-speed grooving test (using water-soluble cutting oil), and cutting edge in any grooving test The cutting groove length was measured until the flank wear width of the outer peripheral edge of the portion reached 0.15 mm, which was a measure of the service life. Table 4 shows the measurement results.
5 respectively.

[0028]

[Table 4]

[0029]

[Table 5]

(Embodiment 3) Under the same conditions as in Embodiment 2 above, the diameters were 8 mm, 13 mm, and 26 mm.
The three types of round bar sintered bodies for forming a cemented carbide substrate were formed, and the three types of round bar sintered bodies were further subjected to grinding processing in a combination shown in Table 6 to obtain the diameter of the groove forming portion × Length is 4mm each
× 13mm, 8mm × 22mm, and 16mm × 45
Drill superhard substrates A to I having dimensions of mm were manufactured, respectively.

Next, the surface of each of the drill superhard substrates A to I is honed, ultrasonically cleaned in acetone, and dried, and then applied to a normal arc ion plating apparatus also illustrated in FIG. Example 1
Under the same conditions as in the above, a physical vapor deposition (Ti, Al) N layer having a target composition (X value) and a target layer thickness shown in Table 6 was used as an inner layer of the hard coating layer on each surface of the cemented carbide substrate. FIG. 4 (a) is a schematic front view of the hard coating layer formed by vapor deposition and further forming a medium temperature chemical vapor deposition Al ₂ O ₃ layer having a target layer thickness also shown in Table 6 on the surface of the inner layer as an outer layer of the hard coating layer. (B) A drill made of the surface-coated cemented carbide of the present invention as the coated carbide tool of the present invention having the shape shown in the schematic cross-sectional view of the groove forming portion (hereinafter referred to as the coated carbide drill of the present invention). 1 to 9 were each manufactured.

For the purpose of comparison, as shown in Table 7, under the same conditions except that the Al ₂ O ₃ layer was not formed under the above-mentioned medium temperature chemical vapor deposition conditions, the hard coating layer was subjected to physical vapor deposition (T
Drills made of comparative surface-coated cemented carbide (hereinafter referred to as comparative coated cemented carbide drills) 1 to 9 as comparative coated cemented carbide tools consisting only of i, Al) N layers were produced.

Similarly, with respect to the hard coating layers of the coated carbide drills 1 to 9 of the present invention and the comparative coated carbide drills 1 to 9 obtained as a result, the composition of each of the constituent layers at the center of the cross section of the thickness was measured by Auger spectroscopy. The thickness was measured using an analyzer and the thickness thereof was measured in cross section using a scanning electron microscope. As a result, the target composition and the target layer thickness shown in Tables 6 and 7 were all substantially the same. .

Next, the coated carbide drills of the present invention 1 to 9
Of the coated carbide drills 1 to 9 of the present invention, the coated carbide drills 1 to 3 and the comparative coated carbide drills 1 to 3 are: Work material: plane dimension: 100 mm × 250 thickness: 50 mm
JIS S45C plate material, Cutting speed: 250 m / min. , Feed: 0.2 mm / rev, wet high-speed drilling test of carbon steel (using water-soluble cutting oil), coated carbide drills 4 to 6 of the present invention and comparative coated carbide drills 4 to 6 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SCM440 plate, Cutting speed: 255 m / min. , Feed: 0.2 mm / rev, wet high-speed drilling test of alloy steel (using water-soluble cutting oil), coated carbide drills 7 to 9 of the present invention and comparative coated carbide drills 7 to 9 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS FC250 plate, Cutting speed: 305 m / min. , Feed: 0.2mm / rev, wet high-speed drilling test (using water-soluble cutting oil) of cast iron, and flank wear of the tip cutting surface in any wet high-speed drilling test The number of holes drilled until the width reached 0.3 mm was measured. The measurement results are shown in Tables 6 and 7, respectively.

[0035]

[Table 6]

[0036]

[Table 7]

[0037]

According to the results shown in Tables 2 to 7, all of the coated carbide tools of the present invention have excellent high-temperature strength and high-temperature hardness, so that cutting of steel is performed at high speed with high heat generation. However, the cutting edge exhibits excellent wear resistance without uneven wear, whereas the hard coating layer is formed by physical vapor deposition (T
i, Al) N layer only, ie medium temperature chemical vapor deposition A
It is clear that in the comparative coated carbide tool without formation of the l ₂ O ₃ layer, the progress of wear is extremely fast due to lack of high temperature hardness. As described above, the coated carbide tool of the present invention exhibits excellent wear resistance not only in cutting under various conditions such as various types of steel and cast iron but also in high-speed cutting, and has a long service life. Therefore, it is possible to satisfactorily cope with labor saving and energy saving of the cutting process and further lowering the cost.

[Brief description of the drawings]

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

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

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

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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C23C 16/34 C23C 16/34 F term (reference) 3C037 CC02 CC04 CC09 3C046 FF03 FF10 FF13 FF16 FF19 FF22 FF25 FF32 FF39 4K029 AA04 BA58 BC02 BD05 EA01 4K030 BA02 BA18 BA38 CA05 LA22

Claims (1)

[Claims] 1. A mass% of Co: 4 to 12%, one or more of titanium carbide, niobium carbide, tantalum carbide, a composite carbide of Nb and Ta, and a composite carbide of Ti and W: 5 ３０30%, tungsten carbide: the remainder, on the surface of a tungsten carbide-based cemented carbide substrate composed of a sintered compact of a compact having a composition of: (a) 0.5 to 10 μm as an inner layer Ti and Al having an average layer thickness and satisfying the composition formula: (Ti _1-x Al _x ) N (where X represents 0.2 to 0.6 in atomic ratio)
(B) As the outer layer, a medium temperature chemical vapor deposition aluminum oxide layer having an average layer thickness of 0.1 to 5 μm, and a hard coating layer composed of the above (a) and (b) are formed. A surface coated cemented carbide cutting tool that demonstrates excellent wear resistance in high-speed cutting.