JP4543373B2 - Method for manufacturing a surface-coated cemented carbide cutting tool that exhibits excellent wear resistance in high-speed cutting of non-ferrous materials - Google Patents

Description

In the present invention, a diamond-like carbon film (hereinafter referred to as a DLC film) formed by plasma CVD (chemical vapor deposition) has the same hydrogen content and a relatively high hardness. The present invention relates to a method of manufacturing a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated carbide tool) that exhibits excellent wear resistance when used for high-speed cutting of non-ferrous materials such as Cu alloys.

In general, as a coated carbide tool, a throw-away tip that is used to attach and detachably attach to the tip of a cutting tool for turning and planing of various non-ferrous materials, drills used for drilling, etc. Known as miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. Also, the throwaway tip is detachably attached, and cutting is performed in the same way as the solid type end mill. The throwaway end mill tool to perform is also known.

Further, as a coated carbide tool, a substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet (hereinafter collectively referred to as a cemented carbide substrate). On the surface)
(A) Through a high-purity diamond-like carbon thin film (hereinafter referred to as a high-purity DLC thin film) which is formed by sputtering and has an average film thickness of 0.005 to 0.2 μm and a purity of 99.9% by mass or more,
(B) A DLC film having a hydrogen content of 10 to 15 atomic% is deposited with an average film thickness of 0.6 to 1.5 μm by plasma CVD.
Coated carbide tools are known, and the hydrogen content in the DLC coating constituting such a coated carbide tool is 10 to 15 atomic% in consideration of strength (chipping resistance) and hardness (abrasion resistance). It is also known that it is defined.

Further, the above-mentioned coated carbide tool is attached to the sputter power source 11 on the opposite side wall sandwiching the turntable 5 as shown in the schematic plan view and the schematic front view in FIGS. 2 (a) and 2 (b), respectively. Further, a plasma CVD apparatus in which a high purity carbon cathode electrode (evaporation source) 10 having a purity of 99.9% by mass or more is disposed, and a source gas inlet 1 is provided on one side wall and an exhaust port 4 is provided on the other side wall. The carbide substrate 6 is placed on the support 8 disposed along the outer peripheral portion on the rotary table 5 installed in the central portion of the apparatus at a position spaced apart from the central axis in the radial direction by a predetermined distance. Wearing,
(A) First, the inside of the apparatus is evacuated, and the inside of the apparatus is heated to, for example, 200 ° C. by the heater 3 installed with the front rotary table sandwiched in the apparatus while maintaining a vacuum of, for example, 8 × 10 ⁻⁵ Pa or less. In addition, a bias voltage (bias power supply 7) of −50 to −500 V is applied to the carbide substrate 6 that rotates while rotating on the rotary table, and then Ar gas is introduced into the apparatus to create a reaction atmosphere in the apparatus. In a state of 0.01 to 0.3 Pa, a pulse power (sputtering power source 11) of 0.4 to 1 kW is applied to the high purity carbon cathode electrode (evaporation source) 10 to start sputtering. High-purity DLC thin film having a purity of 99.9% by mass or more with an average film thickness of 0.002 to 0.2 μm is formed on the surface of the carbide substrate 6 by vapor deposition,
(B) Next, while the inside of the apparatus is heated to, for example, 200 ° C. with the heater 3, the inside of the apparatus is evacuated again, and applied to the above-mentioned carbide substrate 6 while maintaining a vacuum of, for example, 8 × 10 ⁻⁵ Pa or less. The bias voltage (bias power supply 7) to be -500 to -1500 V, and Ar gas was introduced into the apparatus, and the reaction atmosphere in the apparatus was set to 0.01 to 0.3 Pa to generate initial plasma in the apparatus. In this state, hydrocarbons such as acetylene (C ₂ H ₂ ) and hydrogen are introduced as source gases at a flow rate of, for example, C ₂ H ₂ : 165 to 240 cc / min and H ₂ : 50 to 125 cc / min (this In this case, if the introduction ratio of hydrocarbon is relatively reduced and the introduction ratio of hydrogen is increased, the hydrogen content in the DLC film is increased and the hardness is relatively low. If the hydrocarbon introduction ratio is increased and the hydrogen introduction ratio is decreased, the hydrogen content in the DLC film decreases and the hardness becomes relatively low.) (+ C ions and + H ions), a DLC film containing 10 to 15 atomic% of hydrogen and having a hardness of 18 to 22 GPa is applied to the surface of the cemented carbide substrate at an average of 0.6 to 1.5 μm. It is also known to be manufactured by vapor deposition with a film thickness.
JP 2003-26414 A

  In recent years, there has been a strong demand for labor saving, energy saving, and cost reduction with respect to cutting, and with this, cutting tends to increase in speed. However, in the above-mentioned conventional coated carbide tools, the DLC constituting this The coating has a relatively high hydrogen content of 10 to 15 atomic% from the aspect of emphasizing chipping resistance so that it has high strength, while sacrificing its hardness. In the present situation, the wear progresses rapidly, and as a result, the service life is reached in a relatively short time.

In view of the above, the present inventors have focused on the DLC film of the above-mentioned conventional coated carbide tool and conducted research to further improve the wear resistance (hardness improvement). result,
(A) As shown in FIGS. 1 (a) and 1 (b) by a schematic plan view and a schematic front view, respectively, a sputtering power source 11 is also formed for the purpose of forming a high-purity DLC thin film on opposite side walls sandwiching the turntable 5. A high-purity carbon cathode electrode (evaporation source) 10 having a purity of 99.9% by mass or more attached to is disposed, and a plurality of electromagnetic coils 2 are provided at predetermined intervals along the outer periphery of the side wall. A plasma CVD apparatus in which a heater 3 is also provided and a source gas introduction port 1 is provided in the central portion in the lateral direction of the electromagnetic coil so as to penetrate the apparatus, and a magnetic field 9 is formed by the electromagnetic coil. In the state where the magnetic flux density in the mounting portion of the cemented carbide substrate 6 is 50 to 300 G (Gauss) (in this case, the hydrogen content varies depending on the magnetic flux density), first, the high purity DLC thin film is scanned. Film formation in a magnetic field, and further a DLC film is formed by using only hydrocarbons as the raw material gas from the raw material gas inlet 1, and a flow rate within a range of 150 to 250 cc / min. The high-purity DLC thin film having a purity of 99.9% by mass or more and the hydrogen content under the same conditions as the deposition conditions for the high-purity DLC thin film and the DLC film in the conventional plasma CVD apparatus, except for the above conditions When forming a DLC film of 10.2 to 14.8 atomic%, the resulting high-purity DLC thin film is interposed between the cemented carbide substrate 6 and the DLC film, further improving the adhesion between these two, The coating should have a relatively high hardness of 25.3 to 33.1 GPa despite the same hydrogen content of 10.2 to 14.8 atomic%.
(B) In the coated carbide tool formed by vapor-depositing the DLC film of the above (a) with an average film thickness of 0.6 to 1.5 μm through a high-purity DLC thin film formed in a magnetic field, The DLC film contains 10.2 to 14.8 atomic% of hydrogen, which is the same as the conventional DLC film, so that it has sufficient strength and excellent surface smoothness of 24.1 to 30.0 nm in surface roughness. In combination with the effect of improving adhesion by the high-purity DLC thin film, it exhibits excellent chipping resistance and has a relative hardness as compared with the conventional DLC film having a hardness of 18 to 22 GPa. Since it has a high hardness of 25.3 to 33.1 GPa, it should exhibit even better wear resistance.
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. A carbide substrate mounting rotary table is provided in the center of the apparatus, and a sputter power source is provided on the inner surface of the opposite side wall across the rotary table. An attached high-purity carbon cathode electrode (evaporation source) for forming a high-adhesion high-purity DLC thin film having a purity of 99.9% by mass or more is disposed, and a plurality of electromagnetic coils are provided at predetermined intervals along the outer periphery of the side wall. On the other hand, a heater is also provided along the inner circumference of the side wall, and a raw material gas introduction port is provided in the central portion in the lateral direction of the electromagnetic coil so as to penetrate the device, and further radially from the central axis on the rotary table. Using a plasma CVD apparatus in which a plurality of cemented carbide substrates are mounted on a supporting body that rotates and is arranged along the outer peripheral portion at a predetermined distance away,
(A) The inside of the apparatus is heated by a heater and a magnetic field is formed by the electromagnetic coil so that the magnetic flux density at the mounting portion of the cemented carbide substrate is 50 to 300 G (Gauss), and a bias voltage is applied to the cemented carbide substrate. (Bias power supply) is applied, while pulse power (sputtering power supply) is applied to the high purity carbon cathode electrode (evaporation source) to start sputtering, so that 0.002- High-adhesion high-purity DLC thin film having an average film thickness of 0.2 μm and a purity of 99.9% by mass or more is formed by vapor deposition;
(B) Next, the inside of the apparatus is similarly heated by the heater, and the magnetic flux density in the mounting portion of the cemented carbide substrate is maintained at 50 to 300 G (Gauss), and a bias voltage (bias power supply) is applied to the cemented carbide substrate. In the state where initial plasma is generated in the apparatus, a raw material gas consisting of only hydrocarbons is introduced from the raw material gas introduction port, and this is decomposed and converted into plasma, whereby the high adhesion of (a) above is achieved. Through high purity DLC thin film,
Hydrogen content: 10.2-14.8 atomic%,
Hardness: 25.3-33.1 GPa,
Surface roughness: 24.1-30.0 nm,
Average film thickness: 0.6 to 1.5 μm,
It is characterized by a method of manufacturing a coated carbide cutting tool that exhibits excellent wear resistance in high-speed cutting of non-ferrous materials, which is formed by forming a DLC film having the following.

Next, the reason why the high purity DLC thin film and the DLC film constituting the coated carbide tool are numerically limited as described above in the method of the present invention will be described.
(A) High-purity DLC thin film The high-purity DLC thin film has an effect of further improving the adhesion of the DLC film to the carbide substrate by firmly adhering to both the carbide substrate and the DLC film as described above. This adhesion effect is ensured by maintaining the purity at 99.9% by mass or more. Therefore, when the purity is less than 99.9% by mass, the adhesion is drastically lowered. When the film is formed in a magnetic field, the adhesion can be further improved. However, if the average film thickness is less than 0.005 μm, the desired excellent adhesion cannot be ensured. When the film thickness exceeds 0.2 μm and becomes too thick, it has the extremely high hardness, but the characteristic of extremely low strength appears, which is the cause of chipping (small chipping). From Rukoto, defining the average film thickness and 0.005～0.2Myuemu.

(B) DLC coating Generally, the strength and hardness of a DLC coating vary depending on the hydrogen content. When the hydrogen content is less than 10.2 atomic%, high hardness exceeding 33.1 GPa is obtained by magnetic field film formation. However, the strength and surface roughness are reduced, and the surface roughness Ra: 24.1 to 30.0 nm can not be ensured, and chipping (slight chipping) occurs during cutting. On the other hand, when the hydrogen content exceeds 14.8 atomic%, the hardness is drastically reduced, and high hardness of 25.3 GPa or more cannot be ensured even by magnetic field film formation, resulting in rapid wear. since so may progress occurs, the coated cemented carbide tool of the present invention, the hydrogen content of the set and from 10.2 to 14.8 atomic%, more in hardness even with the same hydrogen content by the magnetic field deposition Form a high DLC film Than is.
Moreover, if the average film thickness of the DLC film is less than 0.6 μm, the desired wear resistance cannot be ensured over a long period of time, while if the average film thickness exceeds 1.5 μm, the cutting edge portion Therefore, the average film thickness was determined to be 0.6 to 1.5 μm.

The coated carbide tool manufactured by the method of the present invention is further improved in the adhesion of the high-purity DLC thin film constituting the coated carbide tool formed in a magnetic field, and the hydrogen content of the DLC film is that of the conventional coated carbide tool. Despite the same 10.2 to 14.8 atomic%, it exhibits a relatively high hardness of 25.3 to 33.1 GPa, and thus, at high speed cutting of various Al alloys and Cu alloys, It exhibits excellent wear resistance over a long period of time without occurrence of chipping (slight chipping).

Next, the method for producing the coated carbide tool of the present invention will be specifically described with reference to examples.

As raw material powders, WC powder, TiC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle diameter of 1 to 3 μm, were prepared. The mixture is blended for 96 hours with a ball mill, dried and dried, and then pressed into a green compact at a pressure of 100 MPa, and the green compact is vacuumed at 6 Pa at a temperature of 1400 ° C. for 1 hour. Sintered under holding conditions, polished, and mirror-finished cutting edge rake surface, both of which are made of WC-based cemented carbide and have a chip shape conforming to ISO standard / SPGN120308 A- 1, A-2, A-4, A-5, A-7, A-9, and A-10 were produced.

(A) Next, the purity of 99.97 mass% attached to the sputtering power source 11 is formed on the opposite side wall sandwiching the rotary table 5 with the plasma CVD apparatus shown in FIG. 1 for the purpose of forming a high purity DLC thin film. A high-purity carbon cathode electrode (evaporation source) 10 is disposed, and six electromagnetic coils 2 are provided at predetermined intervals along the outer periphery of the side wall, and a heater is paired with the electromagnetic coil 2 along the inner periphery of the side wall. 3 and a plasma CVD apparatus provided with a source gas introduction port 1 penetrating into the apparatus at the lateral center of the electromagnetic coil, and comprising the above-mentioned carbide substrates A-1 to A-10. The carbide substrate 6 is ultrasonically cleaned in acetone and dried, and is supported on the rotary table 5 in the apparatus in a ring shape at a predetermined distance in the radial direction from the central axis thereof. Body 8 Respectively mounted,
(B) The inside of the apparatus was evacuated and heated to 200 ° C. with the heater 3 while maintaining a vacuum of 6.5 × 10 ⁻⁵ Pa, and 20 r. p. m. On the rotary table rotating at a rotational speed of 20r. p. m. A bias voltage of −120 V is applied to the carbide substrate 6 that rotates while rotating at a rotational speed of 10 μm, while a current of 10 A is applied to the electromagnetic coil 2 to form a magnetic field 9, thereby forming the carbide substrate 6. The magnetic flux density at the installation part of the magnetic flux is 200 G (Gauss),
(C) In this state, Ar gas was introduced into the apparatus to set the reaction atmosphere in the apparatus to 0.08 Pa, and a 0.8 kW pulse power (sputtering) was applied to the high purity carbon cathode electrode (evaporation source) 10. A power source 11) is applied to start sputtering, and a high purity DLC thin film having a target film thickness shown in Table 1 is formed on the surface of the cemented carbide substrate 6 by vapor deposition;
(D) Subsequently, the apparatus was evacuated again with the temperature inside the apparatus maintained at 200 ° C. and the rotation conditions of the cemented carbide substrate 6 being the same , and 6.5 × 10 ⁻⁵ Pa. In a state in which a bias voltage applied to the cemented carbide substrate 6 is set to −700 V as vacuum , Ar gas is introduced into the apparatus, a reaction atmosphere in the apparatus is set to 0.08 Pa , and initial plasma is generated in the apparatus. Acetylene (C ₂ H ₂ ) is introduced as a source gas at a constant flow rate of 200 cc / min to be decomposed and plasma, while a predetermined current in the range of 3 to 20 A is applied to the electromagnetic coil 2 to generate a magnetic field. 9 and the condition that the magnetic flux density in the installation portion of the cemented carbide substrate 6 is a predetermined magnetic flux density within a range of 50 to 300 G (Gauss) (the higher the magnetic flux density is, the more the hydrogen content in the DLC coating is Table) By forming a target film thickness of the DLC film shown in, to produce a present invention coating hard tip 1-7 as the present invention coated carbide tools.

For comparison purposes, a high-purity carbon cathode electrode having a purity of 99.97% by mass attached to the sputter power source 11 on the side wall facing the plasma CVD apparatus shown in FIG. Evaporation source) 10 and heater 3 are arranged, respectively, and a plasma CVD apparatus provided with a source gas inlet 1 on one side wall and an exhaust port 4 on the other side wall is used, except that no magnetic field is formed by the electromagnetic coil 2. Vapor-deposits a high-purity DLC thin film having the target film thickness shown in Table 2 under the same conditions, and when forming a DLC film, C ₂ H ₂ gas and H ₂ gas introduced from the source gas inlet 1 flow rates, respectively _C 2 _{H 2} gas: 165~240cc / min and _H 2: _50~125cc / min vary within the range of hydrogen content Adjusted (in this case by a relatively large amount of C ₂ H ₂ gas flow rate, hydrogen content is kept low by reducing the H ₂ gas flow rate), and the same conditions but for the magnetic field formation by the magnetic coil 2 The conventional coated carbide tips 1 to 7 as the conventional coated carbide tool were manufactured by forming the DLC film having the target film thickness shown in Table 2.

Then, the hydrogen content and hardness of the DLC coating constituting the coated carbide chips 1 to 7 of the present invention and the conventional coated carbide chips 1 to 7 obtained as a result were measured by the recoil scattering analysis method [Elastic Recoil Detection]. [Analysis] (hydrogen content) and nanoindentation method (hardness), respectively, and the surface roughness was measured using an atomic force microscope [Atomic Force Microscope]. The measurement results are shown in Table 2 .
Furthermore, when the thicknesses of the high-purity DLC thin film and the DLC film were measured using a scanning electron microscope (longitudinal section measurement), the average film thickness was substantially the same as the target film thickness (average of five-point measurements). Value).

Next, in a state where the above-described coated carbide chips 1 to 7 and the conventional coated carbide chips 1 to 7 and the conventional coated carbide chips 1 to 7 are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS A6061 (composition is mass%, Si: 0.6%, Fe: 0.7%, Cu: 0.3%, Mn: 0.15%, Mg: 1.0%, Round bars of Cr: 0.1%, Zn: 0.2%, Al and impurities: remaining)
Cutting speed: 1100 m / min. ,
Cutting depth: 10mm,
Feed: 0.5 mm / rev. ,
Cutting time: 90 minutes
Dry continuous high-speed cutting test (normal cutting speed is 600 m / min.) Of Al alloy under the following conditions (referred to as cutting condition A),
Work material: JIS-ADC1 (composition is mass%, Cu: 1.0%, Si: 12.2%, Mg: 0.3%, Zn: 0.45%, Fe: 1.0%, Mn: 0.2%, Ni: 0.4,% Sn: 0.1%, Al and impurities: remaining) round bar,
Cutting speed: 1100 m / min. ,
Incision: 9mm,
Feed: 0.4 mm / rev. ,
Cutting time: 90 minutes
Dry continuous high-speed cutting test (normal cutting speed is 600 m / min.) Of an Al alloy under the conditions (referred to as cutting conditions B),
Work material: JIS C6161 (composition is mass%, Fe: 2.5%, Al: 8.0%, Mn: 1.0%, Ni: 1.0%, Cu and impurities: remaining) Round bar,
Cutting speed: 850 m / min. ,
Cutting depth: 5mm,
Feed: 0.6 mm / rev. ,
Cutting time: 90 minutes
The dry continuous high-speed cutting test (normal cutting speed is 300 m / min.) Of the Cu alloy under the above conditions (referred to as cutting conditions C). In any cutting test, the flank wear width of the cutting edge was measured. The measurement results are shown in Table 2.

As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C (mass ratio, TiC / WC = 50/50) powder, and 1 .8 μm Co powder was prepared, and each of these raw material powders was blended in the blending composition shown in Table 3, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then in a predetermined shape at a pressure of 100 MPa. The green compacts were press-molded, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions , 8 mm in diameter, 13 mm, and 26mm to form a three carbide substrate for forming a round rod sintered body, the further three round bar sintered body of said at grinding, are shown in Table 3 In combination, a carbide substrate (end mill) having a diameter of 4 mm × 13 mm, a length of 6 mm × 13 mm, a size of 10 mm × 22 mm, and a size of 20 mm × 45 mm, and a four-blade square with a twist angle of 30 degrees. ) B-1 to B-7 were produced.

Then, these super-hard substrates (end mills) B-1 to B-7 were ultrasonically cleaned in acetone and dried, and charged into the plasma CVD apparatus shown in FIG. The coated carbide end mills 1 to 7 of the present invention as the coated carbide tool of the present invention were produced by forming a high-purity DLC thin film and a DLC film having the target film thicknesses shown in Table 4 under the same conditions as above.

Further, for the purpose of comparison, the above-mentioned carbide substrates (end mills) B-1 to B-7 were ultrasonically cleaned in acetone and dried, and then loaded into the plasma CVD apparatus shown in FIG. The same conditions as in Example 1 above, that is, the high-purity DLC thin film was not formed in a magnetic field, and when the DLC film was formed, the C ₂ H ₂ gas introduced from the source gas inlet 1 and the flow rate of H ₂ gas, respectively _C 2 _{H 2} gas: 165~240cc / min and _H 2: _50~125cc / min vary within a range of, by adjusting the hydrogen content, and a magnetic field formed by the electromagnetic coil 2 The conventional coated carbide end mills 1 to 7 as the conventional coated carbide tools are formed by forming the high-purity DLC thin film and the DLC film having the target film thickness shown in Table 4 under the same conditions except that Manufactured.

Next, of the present invention coated carbide end mills 1-7 and conventional coated carbide end mills 1-7 , the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS A7075 (composition is mass%, Si: 0.18%, Fe: 0.25%, Cu: 1.6%, Mn: 0.3%, Mg: 2.5%, Cr: 0.23%, Al and impurities: remaining)
Cutting speed: 320 m / min. ,
Incision (groove depth): 12 mm,
Table feed: 1050 mm / min,
With respect to the dry high-speed grooving test of an Al alloy under the conditions (normal cutting speed is 150 m / min.), The coated carbide end mills 4 to 6 and the conventional coated carbide end mills 4 to 6 of the present invention,
Work material: JIS ACD12 (planar dimension: 100 mm × 250 mm, thickness: 50 mm) (composition is mass%, Cu: 3.0%, Si: 12.0%, Mg: 0.3%, Al and Impurity: the remaining plate material,
Cutting speed: 310 m / min. ,
Incision (groove depth): 10 mm,
Table feed: 2050 mm / min,
The dry high-speed grooving test of an Al alloy under the conditions (normal cutting speed is 150 m / min.), The coated carbide end mill 7 of the present invention and the conventional coated carbide end mill 7 are as follows:
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS C2801 (composition is mass%, Cu: 61.0%, Pb: 0.03%, Fe: 0.02%, Zn and Impurity: remaining plate material,
Cutting speed: 180 m / min. ,
Cut (groove depth): 30 mm,
Table feed: 1100 mm / min,
A dry high-speed grooving test (normal cutting speed is 80 m / min.) Of Cu alloy under the above conditions, and the flank wear width of the outer peripheral edge of the cutting edge in each grooving test is a guide for the service life The cutting groove length up to 0.1 mm was measured. The measurement results are shown in Table 4.
Table 4 shows the hydrogen content, hardness, and surface roughness measured under the same conditions as in Example 1 of the DLC film. The measurement results are the results of the above-mentioned carbide substrate (end mill) B- It is the value which the DLC film formed on the surface of this using the test piece of 1- B-7 on the same conditions shows.
Further, regarding the thicknesses of the high-purity DLC thin film and the DLC film, the average film thickness (average value of five-point measurement) is substantially the same as the target film thickness as measured by a scanning electron microscope (longitudinal section measurement). It was confirmed that

The diameters produced in Example 2 above were 8 mm (for forming carbide substrates B-1 to B-3), 13 mm (for forming carbide substrates B-4 to B-6), and 26 mm (for carbide substrates B-). 7 ) (for forming 7 ), and from these three types of round bar sintered bodies, the diameter x length of the groove forming part is 4 mm x 13 mm (carbide substrate C) by grinding. -1 to C-3), 8 mm × 22 mm (carbide substrate C-4 to C-6), and 16 mm × 45 mm (carbide substrate C-7 ), and two blades each having a twist angle of 30 degrees Carbide substrates (drills) C-1 to C-7 having shapes were produced, respectively.

Next, the cutting edges of these carbide substrates (drills) C-1 to C-7 are honed, ultrasonically cleaned in acetone, and dried, and then installed in the plasma CVD apparatus shown in FIG. The coated carbide drill 1 of the present invention as the coated carbide tool of the present invention is formed by forming a high-purity DLC thin film and DLC film having the target film thickness shown in Table 5 under the same conditions as in Example 1 above. ~ 7 were produced respectively.

For comparison purposes, the cutting edges of the above-mentioned carbide substrates (drills) C-1 to C-7 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. A conventional coated carbide tool as a conventional coated carbide tool is inserted into a plasma CVD apparatus and a high-purity DLC thin film and a DLC film having a target film thickness shown in Table 5 are formed under the same conditions as in the first embodiment. Hard drills 1 to 7 were produced, respectively.

Next, among the present invention coated carbide drills 1 to 7 and comparative coated carbide drills 1 to 7 , the present invention coated carbide drills 1 to 3 and the conventional coated carbide drills 1 to 3,
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS · ADC1 (composition is mass%, Cu: 1.0%, Si: 12.2%, Mg: 0.3%, Zn: 0.45%, Fe: 1.0%, Mn: 0.2%, Ni: 0.4,% Sn: 0.1%, Al and impurities: remaining)
Cutting speed: 200 m / min. ,
Feed: 0.6mm / rev,
Hole depth: 10mm,
With respect to the Al alloy wet high-speed drilling test (normal cutting speed is 80 m / min.), The present invention coated carbide drills 4-6 and the conventional coated carbide drills 4-6,
Work Material: Plane Dimensions: 100 mm × 250 mm, Thickness: 50 mm JIS C3560 ((Composition is% by mass, Cu: 63.0%, Pb: 2.5%, Fe: 0.02%, Zn And impurities: the rest of the plate material,
Cutting speed: 300 m / min. ,
Feed: 0.6mm / rev,
Hole depth: 16mm,
With regard to the Cu alloy wet high-speed drilling cutting test (normal cutting speed is 90 m / min.), The coated carbide drill 7 of the present invention and the conventional coated carbide drill 7
Work material: Plane dimension: 100 mm × 250 mm, thickness: 50 mm JIS A7075 (composition is mass%, Si: 0.18%, Fe: 0.25%, Cu: 1.6%, Mn: 0.3%, Mg: 2.5%, Cr: 0.23%, Al and impurities: remaining)
Cutting speed: 220 m / min. ,
Feed: 0.7mm / rev,
Hole depth: 40mm,
We performed high-speed wet drilling test (normal cutting speed of 100 m / min.) Of Al alloy under the above conditions, and the clearance of the tip cutting edge surface in any wet drilling test (using water-soluble cutting oil) The number of drilling processes until the surface wear width reached 0.2 mm was measured. The measurement results are shown in Table 5.
Table 5 shows the hydrogen content, hardness, and surface roughness measured under the same conditions as in Example 1 of the DLC film. The measurement results show the above-mentioned carbide substrate (drill) C- It is the value which the DLC film formed on the surface of this using the test piece of 1- C-7 on the same conditions shows.
Further, regarding the thicknesses of the high-purity DLC thin film and the DLC film, the average film thickness (average value of five-point measurement) is substantially the same as the target film thickness as measured by a scanning electron microscope (longitudinal section measurement). It was confirmed that

From the results shown in Table 1-5, with respect to the hardness of the DLC film, between the present invention coated cemented carbide tools and conventional coated cemented carbide tool is not substantially different from the hydrogen content, i.e. both about 10 The latter only shows a hardness of 18.2 to 21.9 GPa despite the hydrogen content of 15 atomic%, while the former has a relatively high 25.3 to 33.1 GPa. The coated carbide tool of the present invention produced by the method of the present invention, which shows hardness, has a high purity of magnetic film formation compared to conventional coated carbide tools by high-speed cutting of various Al alloys and Cu alloys. In combination with the adhesion improvement effect of the DLC thin film, it is clear that excellent wear resistance is exhibited without occurrence of chipping.
As described above, according to the method of the present invention, excellent wear resistance is achieved not only when cutting under normal conditions, but also when cutting various workpieces under high-speed cutting conditions. Coated carbide tools that exhibit high performance can be manufactured, and can be satisfactorily accommodated in labor saving, energy saving, and cost reduction in cutting.

The plasma CVD apparatus used in order to form the high purity DLC thin film and DLC film of a coated carbide tool by the method of this invention is shown, (a) is a schematic plan view, and (b) is a schematic front view. The plasma CVD apparatus used in order to form the high purity DLC thin film and DLC film of a coated carbide tool by a conventional method is shown, (a) is a schematic plan view, and (b) is a schematic front view.

DESCRIPTION OF SYMBOLS 1 Source gas introduction port 2 Electromagnetic coil 3 Heater 4 Exhaust port 5 Turntable 6 Carbide substrate 7 Bias power supply 8 Support body 9 Magnetic field 10 High purity carbon cathode electrode 11 Sputtering power supply

Claims (1)

A rotating table for mounting a cemented carbide substrate made of a tungsten carbide base cemented carbide is provided in the center of the apparatus, and 99.9% by mass attached to the sputter power supply on the inner surface of the opposite side wall across the rotating table. A high-purity carbon cathode electrode (evaporation source) for forming a high-adhesion high-purity diamond-like carbon thin film having the above purity is disposed, and a plurality of electromagnetic coils are provided at predetermined intervals along the outer periphery of the side wall. A heater is also provided along the same, and a source gas inlet is provided in the central portion in the lateral direction of the electromagnetic coil so as to pass through the apparatus, and further, at a position spaced apart from the central axis on the rotary table by a predetermined distance in the radial direction. Using a plasma CVD apparatus that is arranged along the outer periphery and is equipped with a plurality of cemented carbide substrates on a rotating support,
(A) The inside of the apparatus is heated by the heater and a magnetic field is formed by the electromagnetic coil so that the magnetic flux density in the mounting portion of the cemented carbide substrate is 50 to 300 G (Gauss), and the cemented carbide substrate is biased A voltage (bias power source) is applied, while a pulse power (sputter power source) is applied to the high purity carbon cathode electrode (evaporation source) to start sputtering, whereby 0.002 is applied to the surface of the carbide substrate. Depositing a high-adhesion high-purity diamond-like carbon thin film having an average film thickness of ˜0.2 μm and a purity of 99.9% by mass or more;
(B) Next, the inside of the apparatus is similarly heated by the heater, and the magnetic flux density in the mounting portion of the cemented carbide substrate is maintained at 50 to 300 G (Gauss), and a bias voltage (bias power supply) is applied to the cemented carbide substrate. In the state where initial plasma is generated in the apparatus, a raw material gas consisting of only hydrocarbons is introduced from the raw material gas introduction port, and this is decomposed and converted into plasma, whereby the high adhesion of (a) above is achieved. Through high purity diamond-like carbon thin film,
Hydrogen content: 10.2-14.8 atomic%,
Hardness: 25.3-33.1 GPa,
Surface roughness: 24.1-30.0 nm,
Average film thickness: 0.6 to 1.5 μm,
A method for producing a surface-coated cemented carbide cutting tool exhibiting excellent wear resistance in high-speed cutting of a non-ferrous material, characterized by forming a diamond-like carbon coating having

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