JP2008260097A - Surface-coated cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool whose hard coat layer is excellent in abrasion resistance at a high-speed and high-feed cutting operation and so forth of a highly hard material. <P>SOLUTION: The hard coat layer, which comprises: (a) a lower layer made from (Ti, Al)N layer to satisfy a composition formula: (Ti<SB>1-x</SB>Al<SB>x</SB>)N, in which X ranges from 0.30 to 0.70 by atom ratio; (b) an intermediary layer made from CrN layer; (c) an upper layer consisting of alternate laminated layers of a chromium oxide layer and a molybdenum oxide layer or a tungsten oxide layer, is formed on a super-hard substrate consisting of a tungsten carbide group cemented carbide or a titanium carbonitride based cermet. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  This invention has excellent wear resistance even when cutting hard materials such as hardened alloy tool steels and bearing steels under high-speed and high-feed conditions where a large mechanical load is applied to the cutting blade. The present invention relates to a surface-coated cutting tool to be exhibited (hereinafter referred to as a coated tool).

  In general, coated carbide tools include a throw-away tip that is 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.

Further, as a coated carbide tool, on the surface of a tool base composed of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet,
Composite nitride of Ti and Al satisfying the composition formula: (Ti _1-X Al _X ) N (where X is 0.30 to 0.70 in atomic ratio) [hereinafter referred to as (Ti, Al) N A coated tool formed by physically vapor-depositing a hard coating layer comprising a layer with an average layer thickness of 0.1 to 8.0 μm is known, and is a hard coating layer of the coated tool (Ti, Al) The N layer has high temperature hardness and heat resistance due to Al as a constituent component, and high temperature strength due to the Ti, so excellent cutting when used for continuous cutting and intermittent cutting of various steels and cast irons. It is also known to perform.

Further, the above-mentioned coated tool, for example, the above carbide substrate is loaded into an arc ion plating apparatus which is a kind of physical vapor deposition apparatus shown schematically in FIG. An arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) in which a Ti—Al alloy having a predetermined composition is set in a state heated to a temperature of, for example, a current of 90 A, and at the same time, an apparatus Nitrogen gas is introduced as a reaction gas into the reaction atmosphere of, for example, 2 Pa. On the other hand, the tool substrate is subjected to the above (Ti, Al) on the surface of the tool substrate under the condition that a bias voltage of, for example, −100 V is applied. It is also known that it is produced by vapor-depositing a hard coating layer consisting of N layers.
Japanese Patent No. 2644710

  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. In the case of coated tools, there is no problem when this is used to cut steel or cast iron under normal cutting conditions, but cutting of hard materials such as hardened alloy tool steels and bearing steels in particular. When machining is performed under high-speed, high-feed conditions where a large mechanical load is applied to the cutting edge, high heat is generated during cutting, resulting in insufficient heat resistance at the cutting edge, which causes a relatively short period of time. At present, the service life is reached.

In view of the above, the present inventors have developed the above-mentioned conventional coated tool in order to develop a coated tool exhibiting excellent wear resistance with a hard coating layer particularly in high-speed high-feed cutting of a hard material. As a result of conducting research with a focus on
(A) A (Ti, Al) N layer having an average layer thickness of 0.1 to 8.0 μm, which is a hard coating layer of the conventional coated tool, is used as a lower layer, and a chromium oxide (hereinafter referred to as Cr ₂ O) is formed thereon. ₃ ) is similarly formed with an average layer thickness of 0.1 to 8.0 μm to constitute the upper layer, the Cr ₂ O ₃ layer has a high temperature strength and has a predetermined wear resistance during cutting. However, under severe cutting conditions that involve high heat generation such as high speed and high feed and a large mechanical load on the cutting edge, the heat resistance is insufficient and the wear resistance is sufficiently satisfactory. Not that.

(B) Therefore, in order to improve the heat resistance of the hard coating layer in particular, a Cr ₂ O ₃ layer having an average layer thickness of 0.01 to 1.0 μm and a molybdenum oxide (hereinafter referred to as 0.01 to 1.0 μm). , MoO ₂ ) layers or tungsten oxide (hereinafter referred to as WO ₃ ) layers, which are alternately stacked to form a Cr ₂ O ₃ layer and a MoO ₂ layer having a total average layer thickness of 0.1 to 8.0 μm or When an upper layer composed of an alternating laminated structure with a WO ₃ layer is formed, this upper layer exhibits excellent heat resistance and high temperature hardness in addition to the excellent high temperature strength of the Cr ₂ O ₃ layer.

(C) However, the adhesion between the upper layer composed of the alternately laminated structure of the Cr ₂ O ₃ layer and the MoO ₂ layer or the WO ₃ layer and the lower layer composed of the (Ti, Al) N layer is not sufficient. Peeling is likely to occur under high-speed and high-feed cutting conditions, but when a chromium nitride (hereinafter referred to as CrN) layer is interposed between the upper layer and the lower layer with an average layer thickness of 0.1 to 3 μm, the CrN layer is The Cr ₂ O ₃ layer is combined with the fact that the (Ti, Al) N layer has excellent adhesion to the surface of the tool base because it is firmly adhered to both the upper layer and the lower layer. The hard coating layer in which the CrN layer is interposed between the upper layer composed of the alternately laminated structure of the MoO ₂ layer or the WO ₃ layer is free from delamination even in the high-speed high-feed cutting of the high-hardness material. Show excellent high temperature strength and good Also it shows the hot hardness with excellent and heat, to become to exert over the results excellent wear resistance for long-term.

(D) The hard coating layer of the above (c) is, for example, an arc ion plating apparatus (hereinafter, abbreviated as AIP apparatus) having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. A rotary table for mounting the tool base is provided at the center of the metal substrate, and the rotary table is sandwiched between the metal Cr as the cathode electrode (evaporation source) of the AIP device on one side and the cathode electrode (evaporation) of the AIP device on the other side. As a source), metal Mo (or metal W) is disposed oppositely, and further along the rotary table and at a position 90 degrees away from the cathode electrodes of metal Cr and metal Mo (or metal W). Using a vapor deposition apparatus in which a Ti—Al alloy having a predetermined composition is disposed as a cathode electrode (evaporation source), a position that is a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus. A plurality of tool bases are mounted in a ring shape along the outer periphery of the substrate, and the rotary table is rotated with the atmosphere inside the apparatus as a nitrogen atmosphere in this state, and the layer thickness of the hard coating layer formed by vapor deposition is made uniform. First, arc rotation is first generated between the cathode electrode (evaporation source) of the Ti-Al alloy and the anode electrode while rotating the carbide substrate itself as a lower layer on the surface of the tool substrate. (Ti, Al) N layer is deposited with an average layer thickness of 0.1 to 8.0 μm, and then the arc discharge between the cathode electrode (evaporation source) and the anode electrode of the Ti—Al alloy is stopped, While maintaining the atmosphere inside the apparatus in a nitrogen atmosphere, an arc discharge is generated between the metal Cr, which is the cathode electrode (evaporation source) of the AIP apparatus, and the anode electrode, and a CrN layer of 0.1 to 0.1 is formed as an intermediate layer. 3 μm After vapor deposition with a uniform thickness, the atmosphere in the vapor deposition apparatus is changed to an oxygen atmosphere, and an arc discharge is generated between the metal Cr arranged as the cathode electrode (evaporation source) of the AIP apparatus and the anode electrode, thereby reducing 0 .01 to 1 μm Cr ₂ O ₃ layer is deposited, and then arc discharge is performed between the metal Mo (or metal W), which is the cathode electrode (evaporation source) of the AIP device, and the anode electrode in an oxygen atmosphere. To deposit a 0.01 to 1 μm MoO ₂ layer (or WO ₃ layer), alternately deposit a Cr ₂ O ₃ layer and a MoO ₂ layer (or WO ₃ layer), and obtain a total average layer It is possible to form an upper layer having an alternately laminated structure having a thickness of 0.8 to 8.0 μm.

(E) The coated tool formed by vapor-depositing the hard coating layer composed of the lower layer, the intermediate layer, and the upper layer described above is a high-speed high-feed cutting of a hard material such as a hardened material of alloy tool steel or bearing steel. Even in processing, the (Ti, Al) N layer, which is the lower layer, has excellent high-temperature hardness and heat resistance, and further has excellent high-temperature strength, and the intermediate layer composed of the CrN layer has adhesion between the upper layer and the lower layer, Chipping and delamination are ensured because the upper layer consisting of an alternating laminated structure of Cr ₂ O ₃ layers and MoO ₂ layers (or WO ₃ layers) has excellent heat resistance and excellent high-temperature hardness. It will exhibit excellent wear resistance over a long period of time without any occurrence.
The research results shown in (a) to (e) above were obtained.

This invention was made based on the above research results,
“In a surface-coated cutting tool in which a hard coating layer composed of a lower layer, an intermediate layer, and an upper layer is vapor-deposited on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The lower layer has an average layer thickness of 0.1 to 8.0 μm, and
Composition formula: (Ti _1-X Al _X ) N
(However, in terms of atomic ratio, X represents 0.30 to 0.70) composed of a composite nitride layer of Ti and Al,
The intermediate layer comprises a chromium nitride layer having an average layer thickness of 0.1 to 3 μm,
The upper layer has a total average layer thickness of 0.8 to 8.0 μm, a chromium oxide layer having an average layer thickness of 0.01 to 1.0 μm, and an average layer thickness of 0.01 to 1.0 μm It is configured as an alternately laminated structure with molybdenum oxide layers or tungsten oxide layers having
Coated tool (surface coated cutting tool) "
It has the characteristics.

Next, regarding the constituent layers of the hard coating layer of the coated tool of the present invention, the reason why the numerical values are limited as described above will be described.
(A) Lower layer The Al component in the (Ti, Al) N layer constituting the lower layer improves the high temperature hardness and heat resistance, while the Ti component has the effect of improving the high temperature strength, but the proportion of Al When the X value indicating the ratio to the total amount of Ti is less than 0.30 (atomic ratio, the same shall apply hereinafter), the ratio of Ti is relatively large, which is required for high-speed, high-feed cutting of high-hardness materials. It becomes impossible to ensure excellent high temperature hardness and heat resistance, and the progress of wear is rapidly promoted. On the other hand, when the X value indicating the proportion of Al exceeds 0.70, the proportion of Ti is relatively high. The X value was determined to be 0.30 to 0.70 because the high-temperature strength suddenly decreased and as a result, chipping and the like were likely to occur at the cutting edge.
Also, if the average layer thickness is less than 0.1 μm, it is insufficient to exhibit its excellent wear resistance over a long period of time, while if the average layer thickness exceeds 8.0 μm, the cutting edge Since the chipping is likely to occur in the part, the average layer thickness was determined to be 0.1 to 8.0 μm.

(B) Intermediate layer When the average layer thickness of the intermediate layer composed of the CrN layer is less than 0.1 μm, it is not possible to ensure a strong bonding strength between the upper layer and the lower layer, while the average layer thickness is If it exceeds 3 μm, the strength of the hard coating layer suddenly decreases at the intermediate layer portion, which causes chipping, so the average layer thickness was determined to be 0.1 to 3 μm.

(C) Upper layer The Cr ₂ O ₃ layer constituting the alternately laminated structure of the upper layer has excellent high-temperature hardness, and both the MoO ₂ layer and the WO ₃ layer were excellent in heat resistance. Although it has high-temperature hardness, the Cr ₂ O ₃ layer cannot exhibit excellent high-temperature hardness when its average layer thickness is less than 0.01 μm, and cannot be expected to improve wear resistance. When the average layer thickness exceeds 1.0 μm, the occurrence of chipping can be seen. Therefore, the average layer thickness was determined to be 0.01 to 1.0 μm. In addition, the MoO ₂ layer or the WO ₃ layer cannot improve heat resistance and high-temperature hardness when the average layer thickness is less than 0.01 μm, and the average layer thickness exceeds 1.0 μm. Then, since the occurrence of chipping is observed, the average layer thickness is determined to be 0.01 to 1.0 μm.
In addition, when the total average layer thickness of the upper layer composed of the alternately laminated structure of the Cr ₂ O ₃ layer and the MoO ₂ layer or the WO ₃ layer is less than 0.8 μm, the heat resistance and the high temperature in the high-speed high-feed cutting of the high hardness material. Hardness cannot be improved. On the other hand, when the total average layer thickness exceeds 8.0 μm, chipping is observed. Therefore, the total average layer thickness is 0.8 to 8.0 μm. Determined.
For the molybdenum oxide (MoO ₂ ) layer, the content ratio of Mo and oxygen is shown as 1: 2 (atomic ratio), and for the tungsten oxide (WO ₃ ) layer, the content ratio of W and oxygen is It was shown as 1: 3 (atomic ratio), but molybdenum oxide and tungsten oxide were respectively
Composition formula: Mo _Y O _1-Y
Formula: W _{Z O 1-Z}
In this case, the value of Y (atomic ratio) can be 0.25 ≦ Y ≦ 0.33, and the value of Z (atomic ratio) is 0.25 ≦ Z ≦ 0. 33, and it is not strictly necessary that Mo: oxygen = 1: 2 (atomic ratio) and W: oxygen = 1: 3 (atomic ratio).

In the coated tool of the present invention, the lower layer (Ti, Al) N layer constituting the hard coating layer has excellent high temperature hardness and heat resistance, and excellent high temperature strength, and the intermediate layer CrN layer is the lower layer. In particular, the upper layer composed of an alternating layered structure of Cr ₂ O ₃ layer and MoO ₂ layer or WO ₃ layer has excellent heat resistance and high temperature hardness. Even when high hardness materials such as hardened alloy tool steel and bearing steel are processed under high-speed and high-feed cutting conditions where a large mechanical load is applied, delamination does not occur and excellent wear resistance is maintained over a long period of time. It is something that demonstrates.

  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 in 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, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. TiCN-based cermet tool bases B-1 to B-6 having the following chip shape were formed.

(A) Next, each of the above-mentioned tool bases A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then in the vapor deposition apparatus shown in FIG. Attached along the outer periphery at a predetermined distance in the radial direction from the center axis on the rotary table, metal Cr as the cathode electrode (evaporation source) of the AIP device on one side, and the cathode electrode (evaporation) of the AIP device on the other side As a source), metal Mo or metal W is arranged opposite to each other, and further, along the rotary table and at a position 90 degrees away from each of the metal Cr cathode and metal Mo cathode (or metal W cathode), the cathode electrode of the AIP device A lower layer forming Ti—Al alloy having a predetermined composition is disposed as (evaporation source),
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, and the inside of the apparatus is heated to 700 ° C. with a heater, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied, and a current of 100 A is passed between the metal Cr and the anode electrode of the cathode electrode to generate an arc discharge, whereby the tool base surface is bombarded with the metal Cr,
(C) Introducing nitrogen gas as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, applying a DC bias voltage of −100 V to the rotating tool base while rotating on the rotary table, An arc discharge is generated by flowing a current of 120 A between the Ti-Al alloy and the anode electrode, so that (Ti, Al) N having the target composition and target layer thickness shown in Table 3 is formed on the surface of the tool base. The layer is deposited as a lower layer of the hard coating layer,
(D) The arc discharge between the cathode electrode and the anode electrode of the Ti—Al alloy for forming the lower layer is stopped, the atmosphere in the apparatus is maintained in the same nitrogen atmosphere of 4 Pa, and the DC bias to the tool substrate While maintaining the same voltage (−100V), a current of 120 A was passed between the metal Cr of the cathode electrode and the anode electrode to generate an arc discharge, and thus a CrN layer having the target layer thickness shown in Table 3 was formed. Vapor deposition as an intermediate layer of hard coating layer,
(E) The arc discharge between the metal Cr and the anode electrode is stopped, and the atmosphere in the vapor deposition apparatus is set to an oxygen atmosphere of 1.0 to 3.0 Pa,
(F) Thereafter, a current of 120 A was passed between the metal Cr cathode electrode and the anode electrode to generate arc discharge, and a Cr ₂ O ₃ layer having a target layer thickness shown in Table 3 was deposited. An arc discharge is generated between a metal Mo cathode (or metal W cathode) electrode and an anode electrode in an oxygen atmosphere to deposit a MoO ₂ layer or a WO ₃ layer having a target layer thickness also shown in Table 3,
(G) By repeating the operation of (f) above, the total average target shown in Table 3 is an upper layer composed of an alternating laminated structure of a Cr ₂ O ₃ layer and a MoO ₂ layer or a WO ₃ layer having a predetermined total target layer thickness. By carrying out vapor deposition with a layer thickness, the present coated throwaway tips (hereinafter referred to as the present coated tips) 1 to 16 as the present coated tools were produced, respectively.

  For comparison purposes, these tool bases A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, and each was mounted in the vapor deposition apparatus shown in FIG. A Ti—Al alloy having various composition is attached as a cathode electrode (evaporation source). First, the inside of the apparatus is heated with a heater while evacuating the inside of the apparatus and maintaining a vacuum of 0.1 Pa or less. After heating to 0 ° C., a DC bias voltage of −1000 V is applied to the tool base, and a current of 100 A is passed between the Ti—Al alloy of the cathode electrode and the anode electrode to generate an arc discharge. The substrate surface is bombarded with the Ti—Al alloy, then nitrogen gas is introduced as a reaction gas into the apparatus to form a 3 Pa reaction atmosphere, and a bias voltage applied to the tool substrate is −100 V. An arc discharge is generated between the cathode electrode and the anode electrode of the Ti—Al alloy, and the surface of each of the tool bases A-1 to A-10 and B-1 to B-6 is displayed on the surface. (Ti, Al) N layer having the target composition and target layer thickness shown in FIG. 4 is formed as a hard coating layer by vapor deposition to form a conventional surface-coated carbide throwaway tip (hereinafter referred to as conventional coating) as a conventional coated carbide tool. Chips) 1 to 16 were produced.

Next, in the state where each of the above-mentioned various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1-16 and the conventional coated chips 1-16,
Work material: JIS · SKD11 hardened material (HRC60) round bar,
Cutting speed: 200 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
(Continuous cutting speed and feed are 100 m / min., 0.05 mm / rev., Respectively)
Work material: JIS / SUJ2 quenching material (HRC65) in the longitudinal direction with four equally spaced round bars,
Cutting speed: 220 m / min. ,
Cutting depth: 1.2 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
Dry intermittent high-speed high-feed cutting test of bearing steel under the following conditions (cutting condition B) (normal cutting speed and feed are 100 m / min. And 0.05 mm / rev., Respectively),
Work material: JIS · SKD61 hardened material (HRC61) round bar,
Cutting speed: 180 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
(Continuous cutting speed and feed are 100 m / min. And 0.05 mm / rev., Respectively)
In each cutting test, the flank wear width of the cutting edge was measured. The measurement results are shown in Table 5.

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 powders were prepared, each of these raw material powders was blended in the composition shown in Table 6, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then shaped 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 3 types of tool bar forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm were formed, and the combinations shown in Table 7 were obtained by grinding from the above three types of round bar sintered bodies. The diameter x length of the cutting edge is 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, respectively, and each is made of a WC-based cemented carbide having a four-blade square shape with a twist angle of 30 degrees. Tool substrates (end mills) C-1 to C-8 were produced.

Next, the surfaces of these tool bases (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the vapor deposition apparatus shown in FIG. Under the same conditions, the lower layer composed of the (Ti, Al) N layer having the target composition and the target layer thickness shown in Table 7, the intermediate layer composed of the CrN layer having the target layer thickness also shown in Table 7, and the same table. A hard coating layer composed of an upper layer of a total average target layer thickness also shown in Table 7 consisting of an alternately laminated structure of Cr ₂ O ₃ layers and MoO ₂ layers or WO ₃ layers having a target layer thickness shown in FIG. The surface-coated carbide end mills (hereinafter referred to as the present invention-coated end mills) 1 to 8 as the present invention-coated tools were produced by vapor deposition.

  For comparison purposes, the surfaces of the tool bases (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and charged into the vapor deposition apparatus shown in FIG. By depositing a hard coating layer composed of a (Ti, Al) N layer having the target composition and target layer thickness shown in Table 7 under the same conditions as in Example 1 above, the conventional surface coating superconducting tool as a conventional coating tool is deposited. Hard end mills (hereinafter referred to as conventional coated end mills) 1 to 8 were produced.

Next, of the present invention coated end mills 1 to 8 and the conventional coated end mills 1 to 8, the present coated end mills 1 to 3 and the conventional coated end mills 1 to 3 are as follows:
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD11 quenching material (HRC60),
Cutting speed: 70 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 100 mm / min,
Dry high-speed high-feed grooving test of alloy tool steel under the conditions (normal cutting speed and feed are 20 m / min. And 60 mm / min, respectively)
About this invention coated end mills 4-6 and conventional coated end mills 4-6,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUJ2 quenching material (HRC65),
Cutting speed: 60 m / min. ,
Groove depth (cut): 6 mm,
Table feed: 90 mm / min,
Wet steel (using water-soluble cutting oil) high-speed high-feed groove cutting test under normal conditions (normal cutting speed and feed are 20 m / min. And 60 mm / min, respectively)
For the coated end mills 7 and 8 of the present invention and the conventional coated end mills 7 and 8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 quenching material (HRC61),
Cutting speed: 80 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 120 mm / min,
Dry high-speed high-feed grooving test of alloy tool steel under the conditions (normal cutting speed and feed are 20 m / min. And 60 mm / min, respectively)
In each groove cutting test, 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 Table 7, respectively.

  The diameters produced in Example 2 above were 8 mm (for forming the tool bases C-1 to C-3), 13 mm (for forming the tool bases C-4 to C-6), and 26 mm (tool bases C-7 and C). -8 for forming), 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 (tool base D) by grinding. −1 to D-3), 8 mm × 22 mm (tool base D-4 to D-6), and 16 mm × 45 mm (tool bases D-7 and D-8), and all having a twist angle of 30 degrees 2 WC-base cemented carbide tool bases (drills) D-1 to D-8 having a single-blade shape were produced, respectively.

Next, honing is applied to the cutting edges of these tool bases (drills) D-1 to D-8, ultrasonic cleaning is performed in acetone, and the dried blades are loaded into the vapor deposition apparatus shown in FIG. Under the same conditions as in Example 1, the lower layer composed of the (Ti, Al) N layer having the target composition and target thickness shown in Table 8 and the CrN layer having the target layer thickness also shown in Table 8 are used. It was composed of an intermediate layer and an upper layer having a total average target layer thickness shown in Table 8 consisting of an alternately laminated structure of Cr ₂ O ₃ layers and MoO ₂ layers or WO ₃ layers having the target layer thicknesses also shown in Table 8. By subjecting the hard coating layer to vapor deposition, the surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 8 as the present invention-coated tools were produced.

  For the purpose of comparison, honing is performed on the surfaces of the above-mentioned tool bases (drills) D-1 to D-8, ultrasonic cleaning is performed in acetone, and the vapor deposition apparatus shown in FIG. In the same manner as in Example 1 above, a conventional coating is formed by vapor-depositing a hard coating layer composed of a (Ti, Al) N layer having the target composition and target layer thickness shown in Table 8 as well. Conventional surface-coated carbide drills (hereinafter referred to as conventional coated drills) 1 to 8 as tools were manufactured.

Next, of the present invention coated drills 1 to 8 and the conventional coated drills 1 to 8, the present invention coated drills 1 to 3 and the conventional coated drills 1 to 3 are:
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 quenching material (HRC60),
Cutting speed: 120 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 6 mm,
Wet high-speed high-feed drilling test of alloy tool steel under the following conditions (normal cutting speed and feed are 70 m / min. And 0.15 mm / rev., Respectively),
About this invention coated drill 4-6 and conventional coated drills 4-6,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUJ2 quenching material (HRC65),
Cutting speed: 130 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 5 mm,
Wet high-speed high-feed drilling machining test of bearing steel under the conditions of (normal cutting speed and feed are 70 m / min. And 0.15 mm / rev., Respectively),
About this invention covering drills 7 and 8 and conventional covering drills 7 and 8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SKD61 quenching material (HRC61),
Cutting speed: 140 m / min. ,
Feed: 0.40 mm / rev,
Hole depth: 7 mm,
Wet high-speed high-feed drilling test of alloy tool steel under the conditions of (normal cutting speed and feed are 80 m / min. And 0.2 mm / rev., Respectively),
In each wet high-speed high-feed drilling test (using water-soluble cutting oil), the number of drilling processes until the flank wear width of the tip cutting edge surface reached 0.3 mm was measured. The measurement results are shown in Table 8, respectively.

  As a result, the present coated chips 1 to 16 as the present coated tools, the present coated end mills 1 to 8, the present coated drills 1 to 8, and the conventional coated chips 1 to 16 as conventional coated carbide tools. The composition of the (Ti, Al) N layer (lower layer) constituting the hard coating layer of the conventional coated end mills 1 to 8 and the conventional coated drills 1 to 8 is analyzed by energy dispersive X-ray analysis using a transmission electron microscope. As a result of measurement, each showed substantially the same composition as the target composition.

  Moreover, when the average layer thickness of the constituent layers of the hard coating layer was measured by a cross-section using a scanning electron microscope, all showed an average value (average value of five locations) substantially the same as the target layer thickness.

From the results shown in Tables 3 to 8, all of the coated tools of the present invention are accompanied by high heat generation and high mechanical load on the cutting blade, especially of hard materials such as hardened materials of alloy tool steel and bearing steel. Even in high-speed high-feed cutting, the (Ti, Al) N layer, which is the lower layer of the hard coating layer, has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength, and the intermediate CrN layer is the lower layer. From the fact that the upper layer composed of an alternating laminated structure of Cr ₂ O ₃ layer and MoO ₂ layer or WO ₃ layer has excellent heat resistance and excellent high-temperature hardness, and firmly adheres to the upper layer. In the conventional coated tool in which the hard coating layer is composed of a (Ti, Al) N layer, while the hard coating layer has no delamination and exhibits excellent heat resistance and wear resistance over a long period of time, High speed with high heat generation and high mechanical load The feed cutting, wear progresses because heat resistance and high-temperature hardness is insufficient, which causes, it is clear that lead to a relatively short time service life.

  As described above, the coated tool of the present invention not only performs cutting under normal cutting conditions such as various types of steel and cast iron, but also places a large mechanical load on the cutting blade and generates high heat. Even in the high-speed and high-feed cutting of the above-mentioned high hardness materials, it exhibits excellent wear resistance and excellent cutting performance over a long period of time. It is possible to sufficiently satisfy the labor saving, energy saving, and cost reduction.

The vapor deposition apparatus used in forming the hard coating layer which comprises a coating tool 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 (1)

In a surface-coated cutting tool in which a hard coating layer composed of a lower layer, an intermediate layer, and an upper layer is deposited on the surface of a tool base composed of a tungsten carbide-based cemented carbide or a titanium carbonitride-based cermet,
The lower layer has an average layer thickness of 0.1 to 8.0 μm, and
Composition formula: (Ti _1-X Al _X ) N
(However, in terms of atomic ratio, X represents 0.30 to 0.70) composed of a composite nitride layer of Ti and Al,
The intermediate layer comprises a chromium nitride layer having an average layer thickness of 0.1 to 3 μm,
The upper layer has a total average layer thickness of 0.8 to 8.0 μm, a chromium oxide layer having an average layer thickness of 0.01 to 1.0 μm, and an average layer thickness of 0.01 to 1.0 μm It is configured as an alternately laminated structure with molybdenum oxide layers or tungsten oxide layers having
A surface-coated cutting tool characterized by that.

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