JP2009101474A - Surface-coated cutting tool having hard coating layer capable of exhibiting excellent lubricating performance and wear resistance during high-speed cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool having a hard coating layer capable of exhibiting excellent lubricating performance and wear resistance during the high-speed cutting. <P>SOLUTION: In this surface-coated cutting tool, the hard coating layer is vapor-deposited on the surface of a tool base formed of a tungsten carbide-based sintered alloy or a titanium carbonitride based cermet. The hard coating layer comprises a (Cr, Al) N layer or a (Cr, Al, M) N layer (where M is one or more elements selected from Si or B). Each of the (Cr, Al) N layer and the (Cr, Al, M) N layer is an alternately laminated structure of thin layers A in a cubic structure and thin layers B in a cubic structure and a hexagonal structure which are mixed therein. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  This invention has a high temperature hardness, high temperature strength, high temperature oxidation resistance, and excellent lubricity as well as a hard coating layer, and is therefore used for high-speed cutting of carbon steel and the like with high heat generation. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent wear resistance in some cases and exhibits excellent tool characteristics over a long period of time.

  In general, surface-coated cutting tools include a throw-away tip that is detachably attached to the tip of a cutting tool for turning and planing of various steels and cast irons, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.

Conventionally, as one of surface-coated cutting tools, for example, a substrate (hereinafter collectively referred to as tungsten carbide (hereinafter referred to as WC) based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) based cermet. A coated tool is known in which a uniform nitride and complex nitride (hereinafter referred to as (Cr, Al) N) layer is provided as a hard coating layer on the surface of a tool base). It is known that a coated tool is excellent in wear resistance.
Also known is a coated tool in which a cubic nitride, composite nitride of Cr, Al, and Si (hereinafter referred to as (Cr, Al, Si) N) layer is provided as a hard coating layer on the surface of the tool base. It is known that this coated tool is excellent in fracture resistance and wear resistance.
Furthermore, a coated tool in which a cubic nitride, composite nitride of Cr, Al, and B (hereinafter referred to as (Cr, Al, B) N) layer is provided as a hard coating layer on the surface of the tool base is also known. It is also known that this coated tool is excellent in welding resistance, oxidation resistance, and wear resistance.

Furthermore, the above-mentioned conventional coated tool is loaded with a tool substrate in an arc ion plating apparatus which is one of physical vapor deposition apparatuses shown schematically in FIG. 2, for example, at a temperature of 500 ° C., for example. In a heated state, a Cr—Al alloy having a composition corresponding to the composition of the (Cr, Al) N layer, (Cr, Al, Si) N layer or (Cr, Al, B) N layer which is a hard coating layer, For example, arc discharge is generated between the cathode electrode (evaporation source) on which the Cr—Al—Si alloy or Cr—Al—B alloy is set and the anode electrode under the condition of current: 90 A, and at the same time, the reaction gas is generated in the apparatus. As a reaction atmosphere of, for example, 2 Pa, while the above (Cr, Al) N layer is formed on the surface of the tool base under the condition that a bias voltage of, for example, −100 V is applied to the tool base, Cr, Al, Si) N layer or (Cr, Al, B) are also known to be produced by depositing a hard coating layer consisting of N layers.
JP 9-41127 A Japanese Patent No. 3781374 JP 2005-330539 A

  In recent years, the performance of cutting devices has been dramatically improved, while on the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and with this, cutting tends to be faster. For coated tools, especially when used under high-speed cutting conditions with high heat generation during cutting, the lubricity of the hard coating layer is insufficient, and uneven wear and chipping are likely to occur. The current situation is that the service life is reached in a short time.

In view of the above, the inventors of the present invention have a high-temperature hardness, high-temperature strength, high-temperature oxidation resistance with a hard coating layer, and a coated tool that exhibits excellent lubricity especially in high-speed cutting. As a result of conducting research by focusing on the constituent layers of the hard coating layer of the conventional coated tool, the following knowledge was obtained.
(A) (Cr, Al) N layer, (Cr, Al, Si) N layer or (Cr, Al, B) N layer (hereinafter collectively referred to as the hard coating layer of the conventional coated tool) (Cr, Al, M) N layer, and when component M is contained, M is one or two elements selected from Si or B). Has the effect of improving the high temperature strength and improving the high temperature oxidation resistance in the state where Cr and Al coexist, and when the Si component is contained as the M component, it improves the heat plastic deformation resistance, and B When the components are contained, there is an effect of improving the thermal conductivity, and the hard coating layer has the characteristics of fracture resistance, welding resistance, oxidation resistance and wear resistance by containing these components. Be demonstrated.

(B) By the way, when the composition of the (Cr, Al, M) N layer constituting the hard coating layer of the conventional coated tool is represented by a composition formula: (Cr _{1− (X + Y)} Al _X M _Y ) N, When the content ratio X of Al is small (for example, 0.65 ≦ X), the (Cr, Al, M) N layer is a cubic (Cr, Al, M) N layer (hereinafter referred to as fcc (Cr, If the Al content ratio X is increased, for example, X ≧ 0.75, the crystal structure is a mixed crystal of a cubic structure and a hexagonal structure. (Cr, Al, M) N layer (hereinafter referred to as fcc / hcp (Cr, Al, M) N layer) having a crystal structure in which a cubic structure and a hexagonal structure are mixed. ) Improves the lubrication characteristics, but the fcc / hcp (Cr, Al, M) N layer is Compared to the cc (Cr, Al, M) N layer, the fcc / hcp (Cr, Al, M) N layer is hard because it does not have sufficient high-temperature hardness under high-temperature conditions during high-speed cutting. Satisfactory wear resistance cannot be obtained by vapor deposition alone as a coating layer.

(C) Therefore, the fcc (Cr, Al, M) N layer having excellent high-temperature hardness is used as the thin layer A, and the fcc / hcp (Cr, Al, M) N layer having excellent lubrication characteristics. Is a thin layer B, and the thin layer A and the thin layer B are alternately laminated to form a hard coating layer composed of an alternating laminated structure of the thin layer A and the thin layer B. Without damaging the characteristics of the hard coating layer as a whole, while maintaining excellent wear resistance, it also exhibits excellent lubricity.

This invention was made based on the above research results,
“(1) In a surface-coated cutting tool in which a hard coating layer is vapor-deposited on the surface of a tool base made of tungsten carbide (WC) -based cemented carbide or titanium carbonitride (TiCN) -based cermet, A composite nitride layer of Cr and Al ((Cr, Al) N layer) is formed by vapor deposition. Further, the composite nitride layer of Cr and Al ((Cr, Al) N layer) has a cubic crystal structure. A surface-coated cutting tool (coated tool), characterized in that it is configured as an alternating laminated structure of a thin layer A made of (fcc) and a thin layer B in which a cubic structure (fcc) and a hexagonal structure (hcp) are mixed ).
(2) In the surface-coated cutting tool according to (1), a cubic structure (fcc) of Cr and a composite nitride layer of Cr and Al ((Cr, Al) N layer) and a tool base The surface-coated cutting tool (coated tool) according to (1) above, wherein an underlayer composed of an Al composite nitride layer ((Cr, Al) N layer) is interposed.
(3) In a surface-coated cutting tool in which a hard coating layer is deposited on the surface of a tool base made of tungsten carbide (WC) -based cemented carbide or titanium carbonitride (TiCN) -based cermet, Cr is used as the hard coating layer. And a composite nitride layer ((Cr, Al, M) N layer) of Al and M (where M is one or two elements selected from Si or B) are formed by vapor deposition, and Cr and Al And M composite nitride layer ((Cr, Al, M) N layer) are composed of a thin layer A having a cubic structure (fcc), a cubic structure (fcc) and a hexagonal structure (hcp). A surface-coated cutting tool (coated tool), characterized in that it is configured as an alternately laminated structure of thin layers B mixed with each other.
(4) In the surface-coated cutting tool according to the above (3), a composite nitride layer (Cr, Al, M, where M is one or two elements selected from Si or B) ((Cr, Between the Al, M) N layer) and the tool substrate, a complex nitriding of Cr, Al and M (where M is one or two elements selected from Si or B) having a cubic structure (fcc) The surface-coated cutting tool (coated tool) according to (3) above, wherein an underlayer composed of a physical layer ((Cr, Al, M) N layer) is interposed. "
It has the characteristics.

Next, the hard coating layer of the coated tool of the present invention will be described in more detail.
(A) Thin layer A
The cubic Cr-Al composite nitride layer or the Cr-Al-M composite nitride layer (fcc (Cr, Al, M) N layer) constituting the thin layer A is a high-speed cutting process with high heat generation. , It acts as a layer for maintaining the wear resistance of the hard coating layer.
As already mentioned, the composition of the (Cr, Al, M) N layer is
Formula: when expressed in _{(Cr 1- (X + Y)} Al X M Y) N, the value of the proportion X of Al, by the X ≦ 0.65, as a layer of cubic (fcc) structure Although the wear resistance is maintained by the fcc structure, when the value of the Al content ratio X is X <0.25, the Cr content ratio is relatively increased and the crystal structure is fcc. Even if it exists, the high-temperature hardness of the fcc (Cr, Al, M) N layer itself tends to decrease sharply, making it difficult to ensure the minimum wear resistance required for high-speed cutting. Therefore, the content ratio X of Al in the thin layer A is preferably 0.25 ≦ X ≦ 0.65.
Further, the Cr component, which is a constituent component of the fcc (Cr, Al, M) N layer, improves the high-temperature strength of the thin layer A, contributes to the chipping resistance and fracture resistance of the hard coating layer, and Concomitant content of contributes to the improvement of high-temperature oxidation resistance.
Furthermore, when the M component is contained as a constituent component of the fcc (Cr, Al, M) N layer, the M component can contain one or two elements selected from Si or B. The B component contributes to the improvement of the wear resistance of the thin layer A by improving the heat plastic deformation and the heat conductivity, but the value of the M component content Y (Si When the sum of the content ratio and the B content ratio exceeds 0.1, the high-temperature strength of the thin layer A decreases. Therefore, the content ratio Y of the M component in the thin layer A is 0 ≦ Y ≦ 0.1. It is desirable.

(B) Thin layer B
The thin layer B is composed of a mixed layer of Cr and Al or a mixed nitride layer of Cr, Al, and M (fcc / hcp (Cr, Al, M ) N layer) improves the wear resistance as a result by complementing the lack of lubricity in the thin layer A composed of the fcc (Cr, Al, M) N layer in high-speed cutting with high heat generation. Acts as a layer to let
The effects of the Cr component and the M component, which are constituent components of the thin layer B composed of the fcc / hcp (Cr, Al, M) N layer, are the same as those of the thin layer A.
Speaking of Al, which is a constituent component of the thin layer B, a crystal having a mixed cubic structure (fcc) and hexagonal structure (hcp) by setting the value of the Al content ratio X to X ≧ 0.75. A thin layer B having a structure (fcc / hcp) can be formed, and this fcc / hcp structure ensures lubricity under high-speed cutting conditions with high heat generation, but the value of the Al content ratio X is When X> 0.95, the relative Cr content decreases, the high temperature strength of the fcc / hcp (Cr, Al, M) N layer decreases, and chipping / defects are likely to occur. The Al content ratio X in the layer B is preferably 0.75 ≦ X ≦ 0.95.
Further, when X-ray diffraction was performed on the thin layer B composed of the fcc / hcp (Cr, Al, M) N layer in which the Al content ratio X was in the range of 0.75 ≦ X ≦ 0.95, cubic was obtained. The values β / α of the diffraction peak intensity α from the (200) plane of the crystal structure and the diffraction peak intensity β from the (100) plane of the hexagonal structure are shown in Tables 3-6, 11, 12, 14, As shown in FIG. 15, 0.1 <β / α <11.5.
In addition, when the M component is contained as a constituent component of the thin layer B, in order to prevent the high temperature strength of the thin layer B from being lowered while improving the wear resistance of the thin layer B, as in the case of the thin layer A, The content ratio Y of the M component in the thin layer B is preferably 0 ≦ Y ≦ 0.1.

(C) Alternating lamination of thin layer A and thin layer B If the layer thickness of the thin layer A is less than 0.025 μm, the excellent wear resistance of itself cannot be sufficiently exhibited over a long period of time. The tool life is shortened. On the other hand, if the layer thickness exceeds 0.1 μm, chipping is likely to occur. Therefore, the layer thickness is preferably 0.025 to 0.1 μm.
For the thin layer B, if the layer thickness is less than 0.025 μm, insufficient lubricity of the thin layer A cannot be supplemented. On the other hand, if the layer thickness exceeds 0.1 μm, chipping occurs. Therefore, it is desirable that the thickness of the single layer be 0.025 to 0.1 μm.
Furthermore, the alternate lamination formed by alternately laminating the thin layer A and the thin layer B, when its total layer thickness is less than 1 μm, exhibits its own excellent lubricity and excellent wear resistance over a long period of time. Therefore, if the total layer thickness exceeds 8 μm, chipping tends to occur. Therefore, the total layer thickness is preferably 1 to 8 μm.
Since the thin layer A composed of the fcc (Cr, Al, M) N layer and the thin layer B composed of the fcc / hcp (Cr, Al, M) N layer are hard coating layers of the same component system, they are different from each other. Compared to the alternate lamination of the component thin layers A and B, the adhesion strength between the thin layers A and B is increased, which not only contributes to the improvement of the high temperature strength of the hard coating layer as a whole. There is no risk of peeling.

(D) Underlayer By providing a hard coating layer composed of an alternately laminated structure of thin layers A and thin layers B on the surface of the tool base, as described above, excellent lubricity can be obtained while maintaining wear resistance. However, in order to further improve the wear resistance of the coated tool, an fcc (Cr, Al) N layer or an fcc (Cr) is provided between the surface of the tool base and the alternate lamination of the thin layers A and B. , Al, M) N layers can be further interposed with a layer thickness of 0.1 to 1.5 μm.
The underlying fcc (Cr, Al) N layer or fcc (Cr, Al, M) N layer has the same composition and the same crystal structure as that of the thin layer A, and exhibits excellent wear resistance. For this reason, the wear resistance of the coated tool is further improved.
If the thickness of the underlayer is less than 0.1 μm, further improvement in wear resistance due to the provision of the underlayer cannot be expected. On the other hand, if the thickness of the underlayer exceeds 1.5 μm, high speed cutting is performed. Therefore, the thickness of the underlayer is preferably 0.1 to 1.5 μm.

  In the coated tool of the present invention, the hard coating layer is a thin layer A composed of an fcc (Cr, Al, M) N layer exhibiting excellent wear resistance, and fcc / hcp (Cr, Al, M) Since the thin layer B composed of the N layer has an alternate laminated structure having a high interlayer adhesion strength, or further includes an underlayer having excellent wear resistance, the hard coating layer as a whole has excellent high-temperature hardness, In addition to high-temperature strength and high-temperature oxidation resistance, it also has excellent lubricity, so even with high-speed cutting such as carbon steel with high heat generation, the hard coating layer has excellent wear resistance over a long period of time. To demonstrate.

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

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C for 1 hour, after sintering, WC-based carbide with honing of R: 0.03 on the cutting edge and chip shape of ISO standard CNMG120408 Alloy tool bases A-1 to A-10 were formed.

In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 and ISO standard / CNMG120408. Tool bases B-1 to B-6 made of TiCN-based cermet having the following chip shape were formed.

(A) Next, each of the tool bases A-1 to A-10 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, and then the arc ion plating shown in FIG. Cr-Al for forming a thin layer A having a predetermined composition as a cathode electrode (evaporation source) on one side is mounted along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the apparatus. -As a cathode electrode (evaporation source) on the other side, a Cr-Al-M alloy for forming a thin layer B having the same predetermined component composition is disposed oppositely across the rotary table,
(B) First, the inside of the apparatus is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and then the tool base that rotates while rotating on the rotary table is −1000 V. A direct current bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the thin layer A and the Cr—Al—M alloy for forming the underlayer and the anode electrode, whereby the surface of the tool base is made to the Cr— Bombarded with Al-M alloy,
(C) Next, the flow rate of nitrogen gas as a reaction gas introduced into the apparatus is adjusted to obtain a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table. In this state, a predetermined current in the range of 50 to 100 A is allowed to flow between the cathode electrode and the anode electrode of the thin layer A and the Cr—Al—M alloy for forming the underlayer to generate arc discharge, A base layer made of an fcc (Cr, Al, M) N layer having a predetermined layer thickness is formed on the surface of the tool base by vapor deposition (Tables 4 and 6).
(D) Next, in a state where a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, the cathode electrode and the anode electrode of the thin layer B forming Cr—Al—M alloy An arc discharge is generated by passing a predetermined current in the range of 50 to 100 A between them to form a thin layer B having a predetermined layer thickness on the surface of the cemented carbide substrate, and after forming the thin layer B, an arc discharge is performed. Instead, a predetermined current in the range of 50 to 100 A is passed between the cathode electrode and the anode electrode of the thin layer A and the Cr-Al-M alloy for forming the underlayer to generate an arc discharge, After forming the thin layer A having a predetermined thickness, the arc discharge is stopped, and the thin layer B is formed again by the arc discharge between the cathode electrode and the anode electrode of the Cr-Al-M alloy for forming the thin layer B; For forming thin layer A and underlayer The formation of the thin layer A by the arc discharge between the cathode electrode and the anode electrode of the r-Al-M alloy is alternately repeated, and the surface of the tool base is shown in Tables 3 to 6 along the layer thickness direction. By vapor-depositing a hard coating layer composed of alternating layers of a thin layer A and a thin layer B of the composition and layer thickness (underlayer), the hard coating layer becomes an fcc (Cr, Al, M) N layer and an fcc. / Hcp (Cr, Al, M) N-layered alternating layer structure of the present invention surface coated carbide throwaway tip (hereinafter referred to as the present coated carbide tip) 1-32 Were manufactured respectively.
In addition, only about this invention coated carbide | carbonized_material chips 11-20, 27-32, the base layer was provided in the tool base | substrate surface by the process of said (c).

  For comparison purposes, these tool bases A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plating shown in FIG. The apparatus was charged with Cr—Al—M alloys having the compositions shown in Table 7 as cathode electrodes (evaporation sources), and the apparatus was first evacuated and maintained at a vacuum of 0.1 Pa or less. After heating the inside of the apparatus to 500 ° C. with a heater, a DC bias voltage of −1000 V is applied to the tool base, and a current of 100 A is passed between the Cr—Al—M alloy of the cathode electrode and the anode electrode. Arc discharge is generated, and the tool base surface is bombarded with the Cr-Al-M alloy, and then nitrogen gas is introduced into the apparatus as a reaction gas to obtain a reaction atmosphere of 3 Pa. The bias voltage applied to the tool base is lowered to -100V, and arc discharge is generated between the cathode electrode and the anode electrode of the Cr-Al-M alloy, thereby the tool bases A-1 to A-10 and B A hard coating layer composed of a (Cr, Al, M) N layer having a single-phase / single-crystal structure having the composition and layer thickness shown in Table 7 is deposited on each surface of -1 to B-6. Thus, comparative surface coated carbide throw-away tips (hereinafter referred to as comparative coated carbide tips) 1 to 16 were produced.

Next, the coated carbide chips 1 to 32 of the present invention and the comparative coated carbide chip 1 in the state in which the above various coated carbide chips are screwed to the tip of the tool steel tool with a fixing jig. About ~ 16
Work material: JIS / S50C round bar,
Cutting speed: 300 m / min. ,
Cutting depth: 1.2 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes,
Dry continuous high-speed cutting test of carbon steel under the conditions (cutting condition A) (normal cutting speed is 180 m / min.),
Work material: JIS / SCM440 round bar,
Cutting speed: 320 m / min. ,
Cutting depth: 1.2 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 6 minutes,
Dry continuous high-speed cutting test of alloy steel under the conditions (cutting condition B) (normal cutting speed is 200 m / min.),
Work material: JIS / S30C round bar,
Cutting speed: 330 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes,
The dry continuous high-speed cutting test (normal cutting speed is 180 m / min.) Of carbon steel under the above conditions (cutting condition C) was performed, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Tables 8 and 9.

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 [by 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 10, and then added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressed into 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 Then, three kinds of sintered carbide rod forming bodies for forming a carbide substrate having a diameter of 8 mm, 13 mm, and 26 mm were formed, and further, the above three kinds of round bar sintered bodies were ground and shown in Table 10. WC-based cemented carbide with a 4-blade square shape with a cutting blade portion diameter × length of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, and a twist angle of 30 degrees. Tool bases (end mills) C-1 to C-8 were manufactured.

Then, the surfaces of these carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, a hard coating layer consisting of alternating layers of thin layer A and thin layer B (underlying layer) having the composition and layer thickness shown in Tables 11 and 12 along the layer thickness direction. The present invention as a surface-coated cutting tool according to the present invention, in which the hard coating layer has an alternately laminated structure of fcc (Cr, Al, M) N layers and fcc / hcp (Cr, Al, M) N layers by vapor deposition. Surface coated carbide end mills (hereinafter referred to as the present invention coated carbide end mills) 1 to 16 were produced.
In addition, only about this invention coated carbide end mills 9-16, the base layer was formed in the tool base | substrate surface.

  For the purpose of comparison, the surfaces of the tool bases (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and then mounted on the arc ion plating apparatus shown in FIG. Then, a hard coating layer composed of a (Cr, Al, M) N layer having a single-phase / single-crystal structure having the composition and layer thickness shown in Table 13 is deposited under the same conditions as in Example 1 above. Thus, comparative surface-coated carbide end mills (hereinafter referred to as comparative coated carbide end mills) 1 to 8 were produced.

Next, of the present invention coated carbide end mills 1-16 and comparative coated carbide end mills 1-8,
About this invention coated carbide end mills 1-3, 9-11 and comparative coated carbide end mills 1-3,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / S50C plate material,
Cutting speed: 160 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 500 mm / min,
A carbon steel dry type high speed grooving test (normal cutting speed is 85 m / min.)
About this invention coated carbide end mills 4-6, 12-14 and comparative coated carbide end mills 4-6,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SCM440 plate material,
Cutting speed: 140 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 450 mm / min,
A dry high-speed grooving test of the alloy steel under the conditions (normal cutting speed is 90 m / min.)
For the coated carbide end mills 7, 8, 15, 16 and comparative coated carbide end mills 7, 8 of the present invention,
Work material-Plane: 100 mm x 250 mm, Thickness: 50 mm JIS / S30C plate,
Cutting speed: 150 m / min. ,
Groove depth (cut): 10 mm,
Table feed: 400 mm / min,
A carbon steel dry type high speed grooving test (normal cutting speed is 80 m / min.)
In any of the above groove cutting tests, the cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge reached 0.1 mm, which is a guide for the service life.
The measurement results are shown in Tables 11 to 13, respectively.

The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), and from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding). Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all Tool bases (drills) D-1 to D-8 made of a WC-base cemented carbide having a two-blade shape with a twist angle of 30 degrees were manufactured.

Next, the cutting edges of these tool bases (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. The hard coating layer consisting of the alternating lamination of the thin layer A and the thin layer B having the composition and layer thickness shown in Tables 14 and 15 was deposited under the same conditions as in Example 1 above. By forming the surface of the present invention as a surface-coated cutting tool of the present invention, the hard coating layer has an alternately laminated structure of fcc (Cr, Al, M) N layers and fcc / hcp (Cr, Al, M) N layers. Coated carbide drills (hereinafter referred to as the present invention coated carbide drills) 1 to 16 were produced.
In addition, only about this invention coated carbide drills 9-16, the base layer was formed in the tool base | substrate surface.

  For comparison purposes, honing is applied to the surfaces of the tool bases (drills) D-1 to D-3, D-4 to D-6, D-7, and D-8, and ultrasonic waves are obtained in acetone. After washing and drying, the sample was charged into the arc ion plating apparatus shown in FIG. 2 and the same composition and layer thickness as shown in Table 16 were applied under the same conditions as in Example 1 above. Comparative surface-coated carbide drills (hereinafter referred to as comparative coated carbide drills) 1 to 8 were manufactured by vapor-depositing a hard coating layer composed of a (Cr, Al, M) N layer having a single crystal structure.

Next, of the present invention coated carbide drills 1-16 and comparative coated carbide drills 1-8,
About this invention coated carbide drills 1-3, 9-11 and comparative coated carbide drills 1-3,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / S50C plate material,
Cutting speed: 140 m / min. ,
Feed: 0.15 mm / rev,
Hole depth: 7 mm,
A high-speed wet drilling test of carbon steel under the conditions (normal cutting speed is 80 m / min.),
About this invention coated carbide drills 4-6, 12-14 and comparative coated carbide drills 4-6,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SCM440 plate material,
Cutting speed: 120 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 15 mm,
Wet high-speed drilling machining test of alloy steel under the conditions (normal cutting speed is 70 m / min.),
About the coated carbide drills 7, 8, 15, 16 of the present invention and the comparative coated carbide drills 7, 8,
Work material-Plane: 100 mm x 250 mm, Thickness: 50 mm JIS / S30C plate,
Cutting speed: 110 m / min. ,
Feed: 0.25 mm / rev,
Hole depth: 25 mm,
The carbon steel was subjected to a wet high-speed drilling test (normal cutting speed was 60 m / min.)
In any of the above wet high-speed drilling tests (using water-soluble cutting oil), the number of drilling processes until the flank wear width of the cutting edge surface reached 0.3 mm was measured. The measurement results are shown in Tables 14 to 16, respectively.

As a result, the hard coating layers of the present coated carbide tips 1 to 32, the present coated carbide end mills 1 to 16 and the present coated carbide drills 1 to 16 as the surface coated cutting tool of the present invention are obtained. The composition of each of the base layer, thin layer A and thin layer B is also compared with comparative coated carbide tips 1-16, comparative coated carbide end mills 1-8 and comparative coated carbide drills 1-8 as comparative surface coated cutting tools. When the composition was measured by energy dispersive X-ray analysis using a transmission electron microscope, the composition showed substantially the same composition as the target composition.
Further, when the average layer thickness of the constituent layers of the hard coating layer was measured with a transmission electron microscope, the average value was substantially the same as the target layer thickness (average value at five locations).

Furthermore, the (Cr, Al, M) N layer of the composition constituting the ground layer, thin layer A, and thin layer B of the surface-coated cutting tool of the present invention and (Cr of the composition constituting the hard coating layer of the comparative surface-coated cutting tool. , Al, M) N layers, the crystal structure of each layer was determined by X-ray diffraction, and the results are shown in Tables 3-7 and 11-16.
In addition, for the (Cr, Al, M) N layer of the composition constituting the thin layer B of the surface-coated cutting tool of the present invention, the diffraction peak intensity α from the (200) plane of the cubic structure measured by X-ray diffraction and Tables 3-6, 11, 12, 14, and 15 also show the value β / α of the ratio to the diffraction peak intensity β from the (100) plane of the hexagonal crystal structure.

  From the results shown in Tables 8, 9, and 11 to 16, the surface-coated cutting tool of the present invention has an alternating laminated structure of a thin layer A that exhibits excellent wear resistance and a thin layer B that exhibits excellent lubricity. In addition, the hard coating layer has these excellent characteristics as a whole because it has a high interlayer adhesion strength or an undercoat layer with excellent wear resistance. Even when high-speed machining such as carbon steel is generated, it has excellent wear resistance, whereas the hard coating layer is a single-phase, single-crystal (Cr, Al, M) N layer coating. It is apparent that the tool has chipping and chipping at the cutting edge due to insufficient lubricity of the hard coating layer, and wear progresses rapidly, leading to a service life in a relatively short time.

  As described above, the surface-coated cutting tool of the present invention exhibits excellent wear resistance not only for cutting under normal cutting conditions such as various types of steel and cast iron, but also for high-speed cutting with high heat generation. In addition, since it shows excellent cutting performance over a long period of time, it can sufficiently satisfactorily cope with higher performance of the cutting device, labor saving and energy saving of cutting, and further cost reduction.

The arc ion plating apparatus used for forming the hard coating layer which comprises the surface coating cutting tool of this invention is shown, (a) is a schematic plan view, (b) is a schematic front view. It is a schematic explanatory drawing of a normal arc ion plating apparatus.

Claims (4)

  In a surface-coated cutting tool in which a hard coating layer is deposited on the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet, a composite nitride layer of Cr and Al is deposited as the hard coating layer Further, the composite nitride layer of Cr and Al is formed as an alternately laminated structure of a thin layer A having a cubic structure and a thin layer B in which a cubic structure and a hexagonal structure are mixed. A surface-coated cutting tool characterized by comprising:   2. The surface-coated cutting tool according to claim 1, wherein an underlayer composed of a cubic nitride Cr / Al composite nitride layer is interposed between the Cr / Al composite nitride layer and the tool base. The surface-coated cutting tool according to claim 1.   In a surface-coated cutting tool in which a hard coating layer is vapor-deposited on the surface of a tool base composed of a tungsten carbide-based cemented carbide or a titanium carbonitride-based cermet, Cr, Al, and M are used as the hard coating layer. , One or two elements selected from Si or B) are formed by vapor deposition, and the composite nitride layer of Cr, Al, and M is a thin layer having a cubic crystal structure. A surface-coated cutting tool characterized in that the surface-coated cutting tool is configured as an alternating laminated structure of A and thin layers B in which a cubic structure and a hexagonal structure are mixed.   The surface-coated cutting tool according to claim 3, wherein the Cr, Al, and M (where M is one or two elements selected from Si or B) between the composite nitride layer and the tool substrate, 4. A base layer made of a composite nitride layer of Cr, Al, and M (where M is one or two elements selected from Si or B) having a cubic structure is interposed. The surface-coated cutting tool described.

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