JP2002254210A - Surface-coated cemented carbide cutting tool having excellent wear resistance in heavy cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool having excellent wear resistance in heavy cutting. SOLUTION: The surface-coated cemented carbide cutting tools has a hard coating layer composed of a layer (a) and a layer (b) on the surface of a tungsten carbide group cemented carbide substrate composed of a sintered body of a green compact having a mix composition of 4 to 12% Co in a mass percentage and the remainder composed of tungsten carbide, where the layer (a) is an inside physical deposition compound nitride layer of Ti and Al having an average thickness of 0.5 to 10 μm and satisfying such a composition formula as (Ti1- XAlX)N (where X is 0.2 to 0.6 in an atomic ratio), and the layer (b) is an outside medium temperature chemical deposition aluminum oxide layer having an average thickness of 0.1 to 5 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent toughness and excellent abrasion resistance, and is therefore excellent particularly in cutting under heavy cutting conditions such as high feed and high cutting of various steels. Surface coated cemented carbide cutting tool that exhibits excellent cutting performance over a long period of time (hereinafter referred to as coated cemented carbide tool)
It is about.

[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. Next, an anode electrode and a cathode electrode on which an alloy having a predetermined component composition is set 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 1.3 × 10 ⁻³ Pa with a heater. (Evaporation source), 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, nitrogen gas or the like is introduced as a reaction gas into the apparatus. WC) base cemented carbide substrate (hereinafter, referred to as WC)
A super hard substrate is mounted on the surface of the super hard substrate under the condition that a bias voltage of, for example, -100 V is applied, and a nitride layer of an alloy component constituting the cathode electrode is formed on the surface of the super hard substrate. It is also known that it is manufactured by depositing a hard coating layer made of such as. Furthermore, in the state where the coated cemented carbide tool mounts the cemented carbide substrate in a normal chemical vapor deposition apparatus and heats the inside of the apparatus to a predetermined temperature in the range of 950 to 1050 ° C., as a reaction gas, If the hard coating layer to be formed is, for example, a titanium carbonitride layer, T
iCl ₄ , N ₂ , CH ₃ CN (or CH ₄ ), and H ₂
Mixed gas and α-type and aluminum oxide having a κ-type crystal structure (Al ₂ O indicated by ₃₎ layer a long if AlCl ₃ of
It is also well known that the hard coating layer is manufactured by introducing a mixed gas of CO ₂ , HCl, H ₂ S, and H ₂ and vapor-depositing the hard coating layer on the surface of the ultra-hard substrate by a gas-phase decomposition gas reaction. By the way.

[0004]

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 coupled with higher performance of cutting equipment. Therefore, there is a tendency to perform cutting under heavy cutting conditions such as high feed and high depth of cut, which necessitates the use of coated carbide tools with high toughness. Among hard tools, in particular, in coated hard tools having high toughness, wear progresses rapidly due to insufficient hardness, resulting in a relatively short service life.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, even when used for cutting under heavy cutting conditions where high toughness is required, the cutting edge has excellent toughness without chipping (micro chipping) and excellent cutting performance. As a result of researching to develop a coated carbide tool exhibiting high wear resistance, the following results were obtained.
A cemented carbide substrate consisting of a sintered compact of a compact having a composition of: Co: 4 to 12%, tungsten carbide: remaining, and a hard coating formed by vapor deposition on the surface of the cemented substrate The layer is formed by a physical vapor deposition method such as the above-mentioned arc ion plating method, and has a composition formula: (Ti _1-x Al _x ) N (where X represents 0.2 to 0.6 in atomic ratio). Ti and Al satisfying)
The coated carbide tool specified as a composite nitride [hereinafter, referred to as (Ti, Al) N] layer has a high feed rate and a high depth of cut because the carbide substrate and the hard coating layer have excellent toughness. Demonstrates excellent chipping resistance in cutting under heavy cutting conditions. (B) The coated cemented carbide tool of (a) has excellent toughness as described above and exhibits excellent chipping resistance.
Insufficient hardness leads to rapid wear of the cutting edge, resulting in a relatively short service life. (C) However, on the surface of the coated cemented carbide tool of the above (a), as an outer layer, the reaction gas atmosphere temperature is increased to 750 to 850 ° C. by a normal chemical vapor deposition method (usually 950 as described above). As a high-temperature condition of 〜１０1050 ° C.), when an Al ₂ O ₃ layer having an α-type or κ-type crystal structure is formed, this medium-temperature chemical vapor deposition Al ₂ O ₃ layer is superior to the coated carbide tool of (a). Since it contributes to the improvement of the hardness without impairing the toughness, the inner layer of the physical vapor deposition (Ti, Al) N layer and the intermediate temperature chemical vapor deposition Al ₂ O ₃ are formed on the surface of the resulting superhard substrate having excellent toughness. The coated carbide tool formed by forming a hard coating layer consisting of the outer layer of the layer has both excellent toughness and high hardness. And exhibit excellent wear resistance over a long period of time. 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 comprises a super compact made of a sintered compact of a compact having a composition of 4 to 12% Co and the remainder WC. On the surface of the hard substrate, (a) as an inner layer,
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) 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 formed of the above (a) and (b), and heavy cutting. It is characterized by coated carbide tools exhibiting excellent wear resistance.

Next, in the coated cemented carbide tool of the present invention, the Co content of the cemented carbide substrate, the X value and the average layer thickness of the inner layer of the hard coating layer, and the average layer thickness of the outer layer are as described above. The reason for the limitation will be described. (1) Co Content of Carbide Substrate The Co component has a function of remarkably improving the toughness (strength) of the cemented carbide substrate (sintered body), but if the compounding ratio is less than 4%, the desired high toughness is not obtained. However, when the content exceeds 12%, wear rapidly progresses. Therefore, the content is determined to be 4 to 12%. (2) X value and average layer thickness of inner layer Physical vapor deposition (Ti, Al) constituting inner layer of hard coating layer
Al in the N layer forms a solid solution with respect to extremely soft TiN in order to improve hardness and heat resistance.
Therefore, when the X value of the composition formula: (Ti _1-x Al _x ) N is less than 0.2 in atomic ratio, the desired effect of improving hardness and heat resistance cannot be obtained, while the X value exceeds 0.6. The reason is that the excellent toughness provided by TiN suddenly decreases and also causes chipping.
The X value was determined to be 0.2 to 0.6 in atomic ratio. Further, in order to secure a predetermined wear resistance, the average layer thickness needs to be 0.5 μm or more, while the average layer thickness is 10 μm or more.
When the thickness exceeds 1, the cutting edge portion is liable to be plastically deformed, which causes uneven wear and accelerates abrasion. Therefore, the average layer thickness of the inner layer is set to 0.5 to 10 μm. (3) Average Layer Thickness of Outer Layer As described above, the outer layer has an effect of improving abrasion resistance without impairing the excellent toughness of the cemented carbide substrate and the inner layer. If it is less than 1 μm, the desired effect of improving wear resistance cannot be obtained, while the average layer thickness is 5 μm.
If the average thickness exceeds 0.1 mm, chipping is likely to occur in the cutting edge portion and the service life is shortened, so the average layer thickness is set to 0.1 to 5 μm.

[0008]

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 powder, WC having an average particle size of 1 μm
Using a powder and a Co powder of 1.2 μm, 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 at 100 MPa.
The green compact is press-molded at a pressure of 5 ° C., and the green compact is sintered at a temperature of 1400 ° C. for 1 hour in a vacuum of 6 Pa. After sintering, R: 0.05 Honing was performed to form a chip cemented carbide substrate having the shape of ISO standard CNMG120408.

Next, these super-hard substrates are subjected to ultrasonic cleaning in acetone and dried, and then loaded into a usual arc ion plating apparatus illustrated in FIG. 1, respectively.
On the other hand, a Ti—Al alloy having various compositions as a cathode electrode (evaporation source), and a metal Ti for bombardment of the surface of a super-hard substrate are mounted. After the inside of the apparatus was heated to 500 ° C., an Ar gas was introduced into the apparatus to form an Ar atmosphere of 2.5 Pa. In this state, a bias voltage of −800 V was applied to the super hard substrate, and the surface of the super hard substrate was Ar gas bonded. Bart cleaning, and the bias voltage applied to the carbide substrate is reduced by -1.
00 v, and an arc discharge is generated between the metal Ti of the cathode electrode and the anode electrode to bombard the surface of the super-hard substrate (in this case, the surface portion of the super-hard substrate is 0.1 mm). With a very thin thickness of less than
Depending on the atmosphere of the gas introduced into the apparatus, a titanium nitride layer or a titanium carbonitride layer may be formed depending on the atmosphere of the gas introduced into the apparatus. In an atmosphere, while the bias voltage applied to the super hard substrate was kept at -100 V, the super hard substrate was subjected to arc discharge generated between the Ti-Al alloy of the cathode electrode and the anode electrode. On each surface of the substrate, the target composition (X value) shown in Table 1
And a (Ti, Al) N layer having a target layer thickness is deposited as an inner layer of the hard coating layer, and the surface of the inner layer is further coated with a reaction gas composition in a volume percentage of AlCl ₃ using a conventional chemical vapor deposition apparatus. : 2%, CO ₂ : 3%, H ₂ S: 0.3%, HCl: 1%, H ₂ : remaining, and a normal reaction gas composition, and the reaction atmosphere pressure is also a normal 7 KPa. The reaction atmosphere temperature is a normal reaction atmosphere temperature of 950 to 105.
The Al ₂ O ₃ layer having the target layer thickness also shown in Table 1 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 2, 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.

The hard coating layers of the coated super hard tips 1 to 9 of the present invention and the comparative super hard tips 1 to 9 obtained as described above were subjected to Auger spectroscopy to determine the composition at the center of the thickness section of each of the constituent layers. 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 1 and 2.

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: 180 m / min. Notch: 7.1 mm Feed: 0.21 mm / rev. Cutting time: 5 minutes, dry high-cut continuous turning test of alloy steel under the condition of: 5 minutes, Work material: JIS S45C, longitudinally-elongated round bar with four longitudinal grooves, Cutting speed: 120 m / min. Infeed: 1.5 mm Feed: 0.52 mm / rev. A dry high feed intermittent turning test of carbon steel was performed under the conditions of cutting time: 5 minutes, and the coated carbide tips 6 to 9 of the present invention and the comparative coated carbide tips 6 to 9 were subjected to the following work materials: JIS SCM440 round bar, cutting speed: 180 m / min. , Cut: 1.5mm, Feed: 0.52mm / re
v. Dry high-feed continuous turning test of alloy steel under the conditions of cutting time: 5 minutes Work material: JIS S45C, longitudinally spaced round bar with four longitudinal grooves, Cutting speed: 120 m / min. Infeed: 5.5 mm Feed: 0.25 mm / rev. A dry high-cut intermittent turning test of carbon steel was performed under the conditions of cutting time: 5 minutes, and the flank wear width of the cutting edge portion was measured in each turning test. The measurement results are shown in Tables 1 and 2.

[0013]

[Table 1]

[0014]

[Table 2]

(Example 2) As the raw material powder, the average particle size was as follows:
Using 0.8 μm WC powder and 1.3 μm Co powder, these raw material powders were respectively blended into the blending compositions shown in Table 3, and further added with wax, and added with acetone in acetone.
After mixing with a ball mill for 4 hours and drying under reduced pressure, 100MP
Pressed into various green compacts of a predetermined shape at a pressure of a, and these green compacts are heated at a rate of 7 ° C./min in a vacuum atmosphere of 6 Pa at a predetermined temperature within a range of 1370 to 1470 ° C. After holding at this temperature for 1 hour, sintering was performed under furnace cooling conditions to form three types of round bar sintered bodies for forming a cemented carbide substrate having a diameter of 26 mm, 13 mm, and 8 mm. From the above three types of round rod sintered bodies, the diameter x length of the cutting edge portion was 20 mm x 45 m in each of the combinations shown in Table 3 by grinding.
m, 10 mm x 22 mm, and 6 mm x 13 mm were manufactured respectively.

Then, the surface of the superhard substrate is honed, ultrasonically cleaned in acetone, and dried, and then charged into a usual arc ion plating apparatus also illustrated in FIG. Under the same conditions as in Example 1 above, physical vapor deposition (Ti, A) having a target composition (X value) and a target layer thickness shown in Table 3 was performed on each surface of the cemented carbide substrate.
l) N layer is deposited as an inner layer of the hard coating layer, and a medium temperature chemical vapor deposited Al ₂ O ₃ layer having a target layer thickness also shown in Table 3 is formed as an outer layer of the hard coating layer on the surface of the inner layer. Thus, an end mill made of the surface-coated cemented carbide of the present invention as a coated carbide tool of the present invention having a shape shown in a schematic front view in FIG. 3A and a schematic cross-sectional view of a cutting edge portion in FIG. (Hereinafter referred to as the coated carbide end mill of the present invention) 1 to 9 were produced.

For the purpose of comparison, as shown in Table 4, 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.

For 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 described above, the composition at the center of the thickness section of each of the constituent layers was determined 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, each of the measured values showed substantially the same value as the target composition and target layer thickness shown in Tables 3 and 4. .

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
JIS S45C plate material of 0 mm, Cutting speed: 120 m / min. , Groove depth (cut): 40 mm, Table feed: 1500 mm / min, wet high cut groove cutting test of carbon steel (using water-soluble cutting oil), coated carbide end mills of the present invention 4-6 and comparison For coated carbide end mills 4 to 6, Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0mm JIS FC250 plate material, Cutting speed: 200m / min. Groove depth (cut): 5 mm, Table feed: 6500 mm / min., Dry high feed groove cutting test of cast iron, coated carbide end mill 7 of the present invention
Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS S45 plate material, Cutting speed: 100 m / min. , Groove depth (cut): 12 mm, table feed: 4500 mm / min, wet cutting of carbon steel at high feed rate and high cut depth (using water-soluble cutting oil). Also in the test, the cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge portion reached 0.15 mm, which is a standard of the service life. The measurement results are shown in Tables 3 and 4, respectively.

[0020]

[Table 3]

[0021]

[Table 4]

(Embodiment 3) Under the same conditions as in Embodiment 2 above, the diameters are 8 mm, 13 mm and 26 mm.
Are formed from the three types of round bar sintered bodies for forming a cemented carbide substrate, and the above three types of round bar sintered bodies are subjected to grinding processing in a combination shown in Table 5 to obtain the diameter of the groove forming portion × Length is 4mm each
× 13mm, 8mm × 22mm, and 16mm × 45
Drilled carbide substrates having dimensions of mm were manufactured.

Next, the surface of the superhard substrate is subjected to honing, ultrasonically cleaned in acetone, and dried, and then charged into a usual arc ion plating apparatus also illustrated in FIG. Under the same conditions as in Example 1 above, a physical vapor deposition (T) having a target composition (X value) and a target layer thickness shown in Table 5 was applied to each surface of the cemented carbide substrate.
An i, Al) N layer is deposited as an inner layer of the hard coating layer, and a medium temperature chemical vapor deposition Al ₂ O ₃ layer having a target thickness also shown in Table 5 is formed on the surface of the inner layer as an outer layer of the hard coating layer. By forming the surface-coated cemented carbide of the present invention as a coated cemented carbide tool of the present invention having a shape shown in a schematic front view in FIG. 4A and a schematic cross-sectional view of a groove forming portion in FIG. Drills (hereinafter referred to as coated carbide drills of the present invention) 1 to 9
Was manufactured respectively.

For the purpose of comparison, as shown in Table 6, 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 thickness section was determined by Auger spectroscopy. The thickness was measured by using an analyzer, and the thickness was measured by a cross section using a scanning electron microscope. As a result, the target compositions and target layer thicknesses shown in Tables 5 and 6 were 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: 150 m / min. , Feed: 0.7mm / rev, wet high-feed drilling test of carbon steel (using water-soluble cutting oil), coated carbide drills 4-6 according to the present invention and comparative coated carbide drills 4-6 , Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SCM440 plate, Cutting speed: 150 m / min. , Feed: 0.6 mm / rev, wet high-feed drilling cutting 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
About: Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS FC250 plate, Cutting speed: 200 m / min. , Feed: 0.7mm / rev, wet high-feed drilling test of cast iron (using water-soluble cutting oil), respectively. The number of holes drilled until the width reached 0.3 mm was measured. The measurement results are shown in Tables 5 and 6, respectively.

[0027]

[Table 5]

[0028]

[Table 6]

[0029]

From the results shown in Tables 1 to 6, all of the coated carbide tools of the present invention having excellent toughness and excellent wear resistance have high cutting depth and high cutting performance of steel. Even if the cutting is performed under the heavy cutting conditions, the cutting edge does not cause chipping and exhibits excellent cutting performance over a long period of time. On the other hand, the hard coating layer is formed only by the physical vapor deposition (Ti, Al) N layer. In the configured comparative coated carbide tool, chipping does not occur in the cutting edge portion in the cutting process under the heavy cutting conditions where the high toughness is required, but the wear progresses extremely fast and is relatively short. It is clear that the service life is reached. As described above, the coated carbide tool of the present invention is excellent not only in cutting under various conditions such as steel and cast iron, but also in cutting under high cutting conditions and high feed heavy cutting conditions. Since it exhibits abrasion resistance and exhibits excellent cutting performance over a long period of time, it can sufficiently cope with labor-saving and energy-saving of cutting work, and furthermore, cost reduction.

[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.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23P 15/28 B23P 15/28 A C22C 29/08 C22C 29/08 C23C 14/06 C23C 14/06 A16 / 40 16/40 F term (for reference) 3C037 CC02 CC04 CC09 3C046 FF03 FF10 FF13 FF16 FF19 FF22 FF25 4K018 AD03 FA24 KA15 4K029 AA02 AA04 BA58 BB02 BC02 BD05 CA03 DD06 EA01 GA03 4K030 AA03 JA04

Claims (1)

[Claims] 1. A surface of a tungsten carbide-based cemented carbide substrate composed of a sintered compact of a compact having a composition composition of 4% to 12% of Co, tungsten carbide and the balance of the following: a) The inner layer has an average layer thickness of 0.5 to 10 μm, and has a composition formula: (Ti _1-x Al _x ) N (where X represents 0.2 to 0.6 in atomic ratio). Ti and Al satisfying)
(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 heavy cutting.