JP2013094893A - Surface coated tool excellent in oxidation resistance and wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated drill keeping high wear resistance over a long period of time even under wet and high-speed drilling conditions for a deep hole.SOLUTION: The surface-coated drill is obtained by forming a hard coating layer which includes a (Ti-Al)(N-O) component system as a particle size composition control layer and has a 0.3-5.0 μm thickness directly on a drill base including a cemented carbide sintered compact or high-speed steel or on an outermost surface thereof while interposing an intermediate layer therebetween and satisfies the following conditions. The condition (a) is that Al content ratio x in a film cross section of the particle size composition control layer of a margin part of the drill exists within the range of 0.1-0.6, and a layered high Ti content area in which x is not more than 0.2 and a layered high Al content area in which x is not less than 0.3 exist. The condition (b) is that the aspect ratios A of crystalline grains in the high Ti content area are within 1-5. The condition (c) is that the aspect ratios B of crystalline grains in the high Al content area are 10-70.

Description

  The present invention relates to a surface-coated tool, and more specifically, a chip discharge groove is formed on the outer periphery of the tip of the drill body, and a cutting edge is provided at the tip of the inner peripheral surface of the chip discharge groove facing the drill rotation direction. A surface-coated cutting tool and a surface-coated drill that maintain excellent oxidation resistance and wear resistance over a long period of time, which are used for dry high-speed cutting or wet drilling of workpieces mainly made of carbon steel (S55C) It is about.

  As such a drill, the tip side of a substantially cylindrical drill body rotated about the axis in the rotation direction of the drill is a cutting blade portion, and a pair of chip discharge grooves are formed on the outer periphery of the cutting blade portion. In order to be symmetrical with respect to the axis, the tip of the cutting edge, that is, a spiral that twists toward the rear side in the drill rotation direction around the axis as it goes from the tip flank of the drill body toward the rear end, A so-called two-blade solid drill is known in which a cutting edge is formed at an intersecting ridge line portion with the tip flank on the tip side of the inner circumferential surface of these chip discharge grooves facing the rotation direction of the drill. . Therefore, in such a solid drill, the tip side of the inner peripheral surface of the chip discharge groove facing the drill rotation direction is the rake face of the cutting blade, and the chips generated by the cutting blade are transferred from the rake face to the chip discharge groove. While being in sliding contact with the inner peripheral surface of the metal, it is sent to the rear end side by the twist of the chip discharge groove and discharged. Further, in such a drill, various methods are employed for improving the wear resistance of the drill body.

  For example, in Patent Document 1, an Al highest content point (Ti lowest content point) and an Al lowest content point (Ti highest content point) are alternately present at predetermined intervals in the thickness direction, and the Al highest content point is present. By forming a hard coating layer having a component concentration distribution structure in which the Al (Ti) content continuously changes from the content point to the Al minimum content point and from the Al minimum content point to the Al maximum content point, wear resistance is improved. An improved surface coated drill is disclosed.

  Further, in Patent Document 2, the hard coating is coated from the outer peripheral end of the cutting blade toward the rear end side to a length M within 3 × D with respect to the outer diameter D of the cutting blade. A surface-coated drill that prevents clogging and does not break or break is disclosed.

  Patent Document 3 discloses a surface-coated drill that prevents the occurrence of chip clogging and does not cause breakage or the like by applying a polishing process after coating the inner peripheral surface of the chip discharge groove with a hard coating. Has been.

  Further, in Patent Document 4, a coating layer comprising an outermost layer and an inner layer is provided on the surface of the substrate, the outermost layer is made of aluminum nitride or aluminum carbonitride, and chlorine is contained in the outermost layer in an amount of more than 0 and 0.5 atomic%. A surface-coated drill having excellent lubricity and a long service life is disclosed by containing the following.

  Moreover, in patent document 5, the outermost layer was comprised by CrOy (atomic ratio 0.3 <= y <= 1.5), and the film thickness was provided with the hard coating layer which is 0.01-2.0 micrometers. Discloses a surface-coated drill with improved adhesion resistance or welding resistance.

Further, in Patent Document 6, in a surface-coated cutting tool in which a hard coating layer made of a composite nitride of Cr and Al having a layer thickness of 0.8 to 5.0 μm is deposited on the surface of a tool base, The coating layer is configured as an alternately laminated structure of a thin layer A composed of a granular crystal structure of a composite nitride of Cr and Al and a thin layer B composed of a columnar crystal structure, and each of the thin layer A and the thin layer B is 0.1 The average crystal grain size of the granular crystals constituting the thin layer A is 30 nm or less, and the average crystal grain size of the columnar crystals constituting the thin layer B is 50 to 500 nm. When the surface-coated cutting tool and the composite nitride of Cr and Al are expressed by a composition formula: (Cr _1−X Al _X ) N, 0.55 ≦ X ≦ 0.75 ( However, a surface-coated tool characterized by satisfying X is an atomic ratio) It is shown.

JP 2003-326402 A JP 2003-275909 A JP 2003-275910 A JP 2005-297144 A JP-A-8-132310 JP 2010-94744 A

  In recent years, there has been a dramatic increase in the use of FA for drilling equipment, and in addition, there is a strong demand for labor saving, energy saving, cost reduction, and efficiency for drilling. Although there is a tendency to require drilling, the conventional surface-coated drill does not cause any particular problems when various types of steel and cast iron are drilled under normal conditions. When it is used for wet high-speed deep hole drilling, where wear is required and chips are easily clogged into the drill chip discharge groove, chips are easily clogged in the chip discharge groove, which causes a relatively short period of time. At present, the service life is reached.

In view of the above, the present inventors provide a surface-coated drill that maintains excellent lubricity and wear resistance over a long period of time even when used in wet high-speed deep hole drilling. Therefore, a hard coating layer having a layer thickness of 0.3 to 5.0 μm made of a component system of (Ti _1-x Al _x ) (N _1-y O _y ) is provided on the outermost surface layer of the drill as a particle size composition control layer. As a result of earnest research focusing on the structure of the particle size composition control layer of the existing surface-coated drill, the following findings were obtained.

(A) Layered Ti in which the Al content ratio x in the film cross section of the particle size composition control layer is in the range of x to 0.1 to 0.6, and x is 0.2 or less The high content region and the layered Al high content region where the value of x is 0.3 or more are each included in the grain size composition control layer, and (b) the crystal grains in the Ti high content region Aspect ratio A is 1-5,
(C) The aspect ratio B of the crystal grains in the high Al content region is 10 to 70, and
(D) the oxygen content ratio y is present between 0 and 0.08, and
(E) When the minimum value of y in the high Al content region is 0.04 to 0.08 and the maximum value of y in the high Ti content region is less than 0.03, such hard coating It has been found that a surface-coated drill with a layer exhibits superior lubricity and wear resistance in wet high-speed deep hole drilling compared to conventional surface-coated drills.
When the intermediate layer is provided with a hard coating layer having a layer thickness of 0.5 to 2.0 μm made of carbide, nitride, carbonitride of one or two elements selected from Ti, Al, and Cr Has found that in drilling deep holes, high lubricity and wear resistance can be maintained over a long period of time even when high mechanical load and high lubricity and wear resistance are required at the same time. .
Further, the thickness _{X Ti} of Ti-rich region is present in the range of 30 to 200 nm, and the thickness _{X Al} of Al-rich region is present in the range of 30 to 200 nm, and _{X Ti} in the drill margin portion, A configuration in which X _Al gradually increases in the region from the drill tip to the distance of 5 times the outer diameter of the drill, and X _Al in the drill margin gradually decreases in the region from the drill tip to the distance of 5 times the outer diameter of the drill. It has been found that the combination of the two further improves oxidation resistance and wear resistance while maintaining excellent lubricity.

The hard coating layer as described above has a drill base mounted on an ion plating apparatus using a pressure gradient type Ar plasma gun, which is a kind of physical vapor deposition apparatus shown in the schematic explanatory diagram of FIG. In the state of 400 to 430 ° C., as an intermediate layer,
Evaporation source 1: metal Ti or metal Cr,
Plasma gun discharge power for the evaporation source 1: 10 kW,
Evaporation source 2: Metal Al,
Plasma gun discharge power for the evaporation source 2: 8 kW,
Reaction gas flow rate at reaction gas inlets 1 and 2: Nitrogen (N ₂ ) gas 100 sccm
Plasma gun discharge gas: Argon (Ar) gas 40 sccm each,
DC bias voltage applied to the tool base: -30V,
The specific intermediate layer shown in Table 2 was formed under the conditions
Evaporation source 1: metal Ti,
Plasma gun discharge power for the evaporation source 1: 8-12 kW,
Evaporation source 2: Metal Al,
Plasma gun discharge power for the evaporation source 2: 8-9 kW,
Reaction gas flow rates at the reaction gas inlets 1 and 2 when the tool base is near the evaporation source 1: nitrogen (N ₂ ) gas 100 sccm, oxygen (O ₂ ) gas 0 sccm
Reaction gas flow rate at the reaction gas inlet 1 when the tool base is in the vicinity of the evaporation source 2: nitrogen (N ₂ ) gas 100 sccm,
Reaction gas flow rate at the reaction gas inlet 2 when the tool base is near the evaporation source 2: Nitrogen (N ₂ ) gas 80 to 85 sccm, Oxygen (O ₂ ) gas 5 to 9 sccm
Plasma gun discharge gas: Argon (Ar) gas 40 sccm each,
DC bias voltage applied to the tool base: -15 to -12V,
The surface-coated drill with a hard coating layer formed as a result of this process can be manufactured by performing film formation under the specified conditions. The present inventors have found that excellent oxidation resistance and wear resistance are exhibited while maintaining lubricity. Further, in addition to the above conditions, the tip of the tool base is fixed by a method directed to the rotation center, the rotation shaft is rotated at an angle of 35 to 55 degrees from the normal of the hearth loading surface, and the rotation speed is Ti. Triangular wave-shaped speed control pattern that is maximum at a position closest to Hearth and minimum at a position closest to Hearth of Al, and oxygen gas is flowed only when approaching Hearth of Al, which is superior It has been found that it exhibits lubrication and wear resistance properties.
Furthermore, it has also been confirmed that the above knowledge is applicable not only to drills but also to other cutting tools such as end mills.

The present invention has been made based on the above findings,
“(1) (Ti _1−x Al _x ) (N ₁₋ ) as a particle size composition control layer on the outermost surface directly or via an intermediate layer on a tool base made of cemented carbide sintered body or high speed steel. _In the surface coating tool in which a hard coating layer having a layer thickness of 0.3 to 5.0 μm composed of a component system of _y O _y ) exists,
(A) The value of the Al content ratio x in the particle size composition control layer is
A range of 0.1 to 0.6, and a layered high Ti content region in which the value of x is 0.2 or less, and a layered high Al content region in which the value of x is 0.3 or more , At least one layer in each of the particle size composition control layers, and
(B) The aspect ratio A of the crystal grains in the high Ti content region is 1 to 5, and
(C) The aspect ratio B of the crystal grains in the high Al content region is 10 to 70, and
(D) the oxygen content ratio y is present between 0 and 0.08, and
(E) The minimum value of y in the high Al content region is 0.04 to 0.08, and the maximum value of y in the high Ti content region is less than 0.03. A surface-coated tool that maintains high lubricity and wear resistance.
(2) The thickness XTi of the _Ti- rich region is in the range of 30 to 200 nm, and the thickness XAl of the _Al- rich region is in the range of 30 to 200 nm ( The surface-coated tool according to 1).
(3) The intermediate layer is a hard coating layer having a layer thickness of 0.5 to 2.0 μm made of carbide, nitride, or carbonitride of one or two kinds of elements selected from Ti, Al, and Cr. The surface-coated tool according to (1) or (2), characterized in that it exists.
(4) The tool base is a drill base, and X _Ti in the drill margin portion gradually increases over a region from the tip of the drill to a distance five times the outer diameter of the drill, and X _Al in the drill margin portion is The surface-coated drill according to any one of (1) to (3), wherein the surface-coated drill gradually decreases over a region from the drill tip to a distance of 5 times the outer diameter of the drill. "
It has the characteristics.

  The present invention will be described below.

On the tool base of the surface-coated tool of the present invention, a layer thickness of 0.3 to 5 comprising a component system of (Ti _1-x Al _x ) (N _1-y O _y ) directly or via an intermediate layer A hard coating layer of 0.0 μm is formed. Here, when the layer thickness of the hard coating layer is less than 0.3 μm, desired wear resistance cannot be maintained, while when it exceeds 5.0 μm, chipping of the coating occurs. Therefore, the layer thickness of the hard coating layer is determined to be 0.3 to 5.0 μm.
In the composition of the hard coating layer (Ti _1-x Al _x ) (N _1-y O _y ), if the value of the Al content ratio x is less than 0.1, the wear resistance of Al is not sufficient, and 0 If it exceeds .6, it changes to a hexagonal structure, so the strength of the NaCl-type crystal cannot be maintained. Therefore, the value of the Al content ratio x was set to 0.1 to 0.6.
Further, in the composition of the hard coating layer (Ti _1-x Al _x ) (N _1-y O _y ), if the value of the oxygen content ratio y exceeds 0.08, the brittle Ti oxide during cutting Formation of the film is promoted and the strength of the film cannot be maintained. Therefore, the value of the oxygen content ratio y is set to 0 to 0.08. Further, when the value of the oxygen content ratio y in the high Al content region is less than 0.04, it is not possible to promote the formation of a stable Al oxide, and the y value in the high Ti content region is 0.03 or more. In this case, since the formation of brittle Ti oxide is promoted and the strength is lowered, the value of the oxygen content ratio y in the high Al content region is 0.04 to 0.08, and the oxygen content ratio y in the Ti high content region is The value was determined to be less than 0.03.

Further, if the aspect ratio A of the crystal grains in the Ti-rich region exceeds 5, the stable cutting performance of the granular structure cannot be realized. On the other hand, the value of the aspect ratio A is a value obtained by dividing the long side by the short side, and therefore does not become less than 1. Accordingly, the value of the aspect ratio A is set to 1 to 5.
Further, if the value of the aspect ratio B of the crystal grains in the high Al content region is less than 10, the wear resistance of the columnar structure cannot be realized. On the other hand, if the value of aspect ratio B exceeds 70, the bending strength against shearing force cannot be maintained. Therefore, the value of the aspect ratio B is set to 10 to 70.
The “aspect ratio” as used in the present invention refers to the value of the long side, which is a line segment indicating the measured maximum diameter of each crystal grain, and the value of the short side indicating the minimum diameter in the direction perpendicular to the long side. The value divided by the value.

When the thickness of the intermediate layer is 0.5 μm or less, not only the wear resistance of the film is not sufficient, but also the interface that can be the starting point of peeling is not increased, so the fracture resistance of the tool is not improved. When the layer thickness exceeds 2.0 μm, chipping due to residual stress is likely to occur, so the wear resistance of the tool is not improved. Therefore, the layer thickness of the intermediate layer is set to 0.5 to 2.0 μm.

When the value of the thickness X _{Ti of the Ti-} rich region and the thickness X _Al of the _Ti- rich region is less than 30 nm, the respective lubricant properties, oxidation resistance, and wear resistance cannot be exhibited. On the other hand, when X _Ti exceeds 200 nm, the ratio of the Ti high content region inferior in wear resistance as compared with the Al high content region is relatively large, and the destruction in the Ti high content region is likely to occur. It can not be maintained for tool performance, and if X _Al exceeds 200 nm, the integrated value of the compressive stress introduced in the Al-rich region becomes too large, causing chipping of the coating. _Therefore, the value of _{X Ti} and _{X Al} was determined to be 30 to 200 nm.
Further, when the tool base is a drill base, that is, when the surface-coated tool is a surface-coated drill, X _Ti in the drill margin gradually increases over a region from the drill tip to a distance of 5 times the drill outer diameter. In addition, X _Al in the drill margin portion is configured to gradually decrease over a region from the drill tip to a distance of 5 times the outer diameter of the drill. Thus, high wear resistance is maintained.
Here, “region from the tip of the drill to a distance of 5 times the outer diameter of the drill” is measured in the direction of the shank backward, that is, in the direction of the shank, starting from the tip of the drill cutting edge parallel to the center axis of the drill. An area up to five times the maximum diameter in a plane perpendicular to the central axis.
Moreover, when there are a plurality of Ti-rich regions or a plurality of Al-rich regions in the film thickness direction in the same measurement region, the average values are X _Ti and X _Al , respectively.

The surface-coated tool of the present invention has a particle size composition control layer (Ti _1-x Al _x ) on the outermost surface directly or via an intermediate layer on a tool base made of cemented carbide sintered body or high-speed steel. In a surface-coated tool having a hard coating layer having a layer thickness of 0.3 to 5.0 μm composed of a component system of (N _1-y O _y ), (a) Al content in the film section of the particle size composition control layer The ratio x is present in the range of 0.1 to 0.6, and the layered Ti-rich region where the value of x is 0.2 or less, and the layered value of x is 0.3 or more (B) the aspect ratio A of the crystal grains in the high Ti content area is 1 to 5; and (c) the aspect ratio B of the crystal grains in the high Al content area. Is 10 to 70, so that it has high lubricating properties, chipping resistance and acid resistance over a long period of time. It is characterized by a surface-coated tool that maintains its chemical resistance and wear resistance.
Furthermore, when the thickness XTi of the _Ti- rich region is in the range of 30 to 200 nm and the thickness XAl of the _Al- rich region is in the range of 30 to 200 nm, the oxidation resistance and wear resistance The property can be further improved.
Also, if the tool substrate is a drill base, X _Ti in the drill margin portion is gradually increased toward the area from the drill tip to five times the distance of the drill outer diameter, and, X _Al in the drill margin portion, the drill tip The wear resistance can be further improved by forming so as to gradually decrease over a range from a distance of 5 to the outer diameter of the drill.
That is, in general deep hole processing, at the tip portion where mechanical load is high and high heat resistance is required at the same time, a high Al content region having a high Al content ratio is larger than a Ti high content region. By configuring with a columnar structure, high wear resistance is maintained over a long period of time. On the other hand, in the chip discharge groove and the margin part behind the drill where slip characteristics and stable wear form are required rather than mechanical load, high Ti content with a high Ti content ratio to further utilize the lubricating properties of TiN By configuring the region with a granular structure having a low aspect ratio, it is possible to maintain high lubrication characteristics over a long period while maintaining a minimum wear resistance. At the same time, by laminating these regions in the film thickness direction, the progress direction of cracks that progress in the film thickness direction generated in the Al-rich region mainly composed of a columnar structure is the Ti-rich region. Dispersed by the fine granular structure, the impact resistance of the film can be improved.
Furthermore, X _Ti gradually increases from the drill tip to the region 5 times the outer diameter of the drill, and X _Al gradually decreases from the drill tip to the region five times the outer diameter of the drill. From the vicinity of the tip where wear resistance is required to the rear of the tool where lubrication characteristics are required, the effects of both can be expressed in a balanced manner, and the tool life can be extended.
Furthermore, according to the present invention, the composition ratio and the aspect ratio change continuously in the film thickness direction, or X _Al and X _Ti gradually change in the drill axis direction. It achieves extremely stable cutting and longer life than the conventional technology that is continuously processed. According to a general production method, even if the Al content ratio x is changed, the granular structure / columnar structure does not change dominantly depending on the Al content ratio x. The surface-coated drill of the present invention can be controlled by arranging the substrate rotation mechanism, the Ti evaporation source, and the Al evaporation source in a very unique arrangement and realizing a specific film formation speed distribution and a density distribution of Ti ions and Al ions. It can be manufactured in a state.

The plane schematic diagram of the ion plating apparatus using the pressure gradient type Ar plasma gun for carrying out vapor deposition formation of the hard coating layer (particle size composition control layer) of the surface coating tool of the present invention is shown. The cross-sectional schematic diagram of the hard coating layer (particle size composition control layer) of the surface coating tool of this invention is shown. 1 represents a schematic out-of-plane view of an arc ion plating apparatus for forming a conventional coated tool by vapor deposition.

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

As raw material powders, WC powder having an average particle size of 0.8 μm, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, and 1.8 μm Co powder were prepared. 1 is added to the compounding composition shown in FIG. 1, and a wax is further added, followed by ball mill mixing in acetone for 24 hours, drying under reduced pressure, and then press-molding into various compacts of a predetermined shape at a pressure of 100 MPa. The body is heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a heating rate of 7 ° C./min in a vacuum atmosphere of 6 Pa, held at this temperature for 1 hour, and then sintered under furnace cooling conditions. Then, a round tool sintered body for forming the tool base is formed, and further, the diameter x length of the groove forming part is 10 mm x 80 mm and the helix angle is 30 degrees by grinding from the round bar sintered body. A WC-based cemented carbide drill with a two-blade shape From the bases D-1 to D-4 and the same round bar sintered body, the diameter of the groove forming part × length is 6 mm × 48 mm, the twist angle is 30 degrees, and the tip is 3 mm 2 by grinding. End mill substrates E-1 to E-4 made of a WC-base cemented carbide having a single-blade shape were produced.

Next, honing is applied to the cutting edges of these drill bases D-1 to D-4 and end mill bases E-1 to E-4, and drill bases D-1 to D-4 and end mill bases E-1 to E- 4 is ultrasonically cleaned in acetone and dried, and is attached to an ion plating apparatus using a pressure gradient type Ar plasma gun which is one of physical vapor deposition apparatuses shown in the schematic diagram of FIG. With the temperature set at 400 to 430 ° C., as an intermediate layer,
Evaporation source 1: metal Ti or metal Cr,
Plasma gun discharge power for the evaporation source 1: 10 kW,
Evaporation source 2: Metal Al,
Plasma gun discharge power for the evaporation source 2: 8 kW,
Reaction gas flow rate at reaction gas inlets 1 and 2: Nitrogen (N ₂ ) gas 100 sccm
Plasma gun discharge gas: Argon (Ar) gas 40 sccm each,
DC bias voltage applied to the tool base: -30V,
The specific intermediate layer shown in Table 2 was formed under the conditions
Evaporation source 1: metal Ti,
Plasma gun discharge power for the evaporation source 1: 8-12 kW,
Evaporation source 2: Metal Al,
Plasma gun discharge power for the evaporation source 2: 8-9 kW,
Reaction gas flow rates at the reaction gas inlets 1 and 2 when the tool base is near the evaporation source 1: nitrogen (N ₂ ) gas 100 sccm, oxygen (O ₂ ) gas 0 sccm
Reaction gas flow rate at the reaction gas inlet 1 when the tool base is in the vicinity of the evaporation source 2: nitrogen (N ₂ ) gas 100 sccm,
Reaction gas flow rate at the reaction gas inlet 2 when the tool base is near the evaporation source 2: Nitrogen (N ₂ ) gas 80 to 85 sccm, Oxygen (O ₂ ) gas 5 to 9 sccm
Plasma gun discharge gas: Argon (Ar) gas 40 sccm each,
DC bias voltage applied to the tool base: -15 to -12V,
Film formation was performed under the specific conditions shown in Table 2. Further, in addition to the above-mentioned conditions, the tip of the drill base is fixed by a method directed to the rotation center, the rotation shaft is rotated at an angle of 35 to 55 degrees from the normal of the hearth loading surface, and the rotation speed is Ti. It is a triangular wave-shaped speed control pattern that is maximum at a position closest to Hearth and minimum at a position closest to Hearth of Al. Reactive deposition is performed with oxygen gas flowing only when approaching Hearth of Al. The present invention surface-coated drills 1 to 30 having the composition shown in Table 2 and the target particle thickness and average aspect ratio shown in Tables 4 and 5, and the composition shown in Table 2 were formed. And the surface covering end mills 1 to 4 of the present invention in which the particle size composition control layer having the target average film thickness and the average aspect ratio shown in Table 7 were formed, respectively.

For the purpose of comparison, the surfaces of the drill bases D-1 to D-4 and the end mill bases E-1 to E-4 are subjected to honing, ultrasonically cleaned in acetone, and dried.
As shown in FIG. 3, the drill base is held and rotated in an arc ion plating apparatus attached with a Ti—Al alloy as a target while rotating in the vertical direction, and at the same time, the vertical axis is used as a rotation center axis. In the state where the tool base temperature is 410 to 430 ° C.,
Target 3: Ti—Al alloy or Cr—Al alloy Arc discharge current for target 3: 130 A,
Gas pressure in the chamber: 6 Pa,
Nitrogen (N ₂ ) gas ratio: 100%,
DC bias voltage applied to the tool base: -50V,
The specific intermediate layer shown in Table 2 was formed under the conditions
Target 1: Ti-Al alloy,
Arc discharge current for target 1: 50-130A,
Target 2: Ti-Al alloy,
Arc discharge current for target 2: 50-110A,
Gas pressure in the chamber: 5-8 Pa,
Among them, oxygen (O ₂ ) gas ratio: 5 to 10%,
Nitrogen (N ₂ ) gas ratio: DC bias voltage applied to the remaining tool base: −25V,
Under the specific conditions shown in Table 3, the conventional coating layer is formed by vapor deposition, and the composition shown in Table 3 and the aspect shown in Table 6 are formed on the surfaces of the drill bases D-1 to D-4. Comparison, surface-coated drills 1 to 8 having a conventional layer having an average film thickness and a composition shown in Table 3 and a target average film thickness and a particle size composition control layer having an average aspect ratio shown in Table 7 were formed. Comparative surface-coated end mills 1 to 4 were produced, respectively.

Next, for the surface-coated drills 1 to 30 and the comparative surface-coated drills 1 to 8 of the present invention,
Work material—planar dimensions: 100 mm × 250 mm, thickness: 80 mm, JIS S45C (HB260) plate material,
Cutting speed: 100 m / min. ,
Feed: 0.30 mm / rev. ,
Hole depth: 50mm,
Wet high-speed deep drilling cutting test of alloy steel under the conditions of (normal cutting speed and feed of drilling hole depth 5D are 90 m / min. And 0.25 mm / rev., Respectively),
Then, the number of drilling operations was measured until the flank wear width of the cutting edge surface reached 0.3 mm, or until the tool chipped. The measurement results are shown in Tables 4, 5, and 6, respectively.
Next, for the surface-coated end mills 1 to 4 and the comparative surface-coated end mills 1 to 4 of the present invention,
Work material-planar dimensions: 200 mm × 250 mm, thickness: 100 mm, JIS S45C (HB240) plate material,
Cutting speed: 280 m / min. (Tool rotation speed: 15000 rotations),
Table feed: 0.4 mm / rev. ,
Depth cut depth: 0.30mm
Feed cut depth: 1.0mm
Wet high-speed end mill cutting test of carbon steel under the conditions (normal cutting speed and table feed are 245 m / min. (Tool rotation speed 13000 rotation) and 0.3 mm / rev., Respectively) The cutting length was measured until the flank wear width of the surface reached 0.2 mm or until the tool was broken. The measurement results are shown in Table 7, respectively.

  As a result, the surface coating drills 1 to 30 of the present invention, the modified particle size composition control layer constituting the hard coating layer of the surface coating end mills 1 to 4 of the present invention, the comparative surface coating drills 1 to 8, the comparative surface coating When the average layer thickness of the conventional layers constituting the hard coating layers of the end mills 1 to 4 was measured with a scanning electron microscope, the average value was substantially the same as the target layer thickness (average value of five locations). showed that.

Further, the surface-coated drills 1 to 30 according to the present invention, the surface-coated drills 1 to 8 according to the present invention, the surface-coated end mills 1 to 4 according to the present invention, and the surface-coated end mills 1 to 4 with a focused ion beam processing apparatus are Equivalent to twice the layer thickness x width: 5 μm x thickness: 100 nm
The modified particle size composition constituting the hard coating layers of the surface-coated drills 1 to 30 of the present invention under the condition of an observation acceleration voltage of 200 kV using a transmission electron microscope (JEM-2010F) After observing the grain size structure of the conventional layer constituting the hard coating layer of the control layer and the comparative surface coating drills 1 to 8, the coating is formed substantially perpendicular to the tool substrate from the intersection of the center line in the width direction of the flake and the tool substrate. In the direction of the surface, the composition is measured at intervals of 10 nm, and it is confirmed that the composition at each point has substantially the same composition range as the target composition range shown in Tables 2 and 3. , the average thickness of the Ti-rich region content x of Al is 0.1 to 0.2 _{X Ti} and, included in the Ti-rich region _{(Ti 1-x Al x)} (N 1-y O y ) Long side of the crystal grains consisting of the component system and Sides was measured to calculate the aspect ratio A, also, the proportion x of Al is 0.3 or more 0.6 Al high average thickness _{X Al-containing} region and equal to or less than, be included in the Al-rich region (Ti _1−x Al _x ) (N _1−y O _y ), the long and short sides of the crystal grains are measured, the aspect ratio B is calculated, and the results are shown in Tables 4, 5, 6, 7 It was shown to. In addition, the long side said here represents the length of the line segment which shows the maximum length in a crystal grain, and a short side is the length of the line segment with the minimum length among the line segments perpendicular to the long side. The aspect ratio is a value obtained by dividing the long side by the short side.

From the results shown in Tables 2, 4, 5, and 7, the surface-coated drill of the present invention and the surface-coated end mill of the present invention were formed from a component system of (Ti _1-x Al _x ) (N _1-y O _y ) on the outermost surface. The particle size composition control layer is formed, the layer thickness is 0.3 to 5.0 μm, and the Al content ratio x in the film cross section of the particle size composition control layer is 0.1 to 0.6. In the range, there is a layered high Ti content region where the value of x is 0.2 or less and a layered high Al content region where the value of x is 0.3 or more, and in the high Ti content region The aspect ratio A of the crystal grains is 1 to 5, the aspect ratio B of the crystal grains in the high Al content region is 10 to 70, and the thickness X _{Ti of the} high Ti content region is in the range of 30 to 200 nm. It exists, and the thickness _{X Al} of Al-rich region, lies in the range of 30~200nm Since that, it is clear that the surface coated drill and surface coating end mill to maintain the excellent oxidation resistance and wear resistance over a long time can be obtained.
Further, X _Ti in the drill margin portion is gradually increased toward the area from the drill tip to five times the distance of the drill outer diameter, and, X _Al in the drill margin portion, a distance from the drill tip five times the drill outer diameter It is clear that the gradual decrease over the region up to this yields a surface-coated drill that maintains excellent lubricity and wear resistance over time.
On the other hand, from the results shown in Tables 3, 6 and 7, there is no high content region of Ti and Al in the hard coating layer, or the aspect ratio and layer thickness of the high content region of Ti and Al are predetermined. In comparative surface-coated drills and comparative surface-coated end mills that have conventional layers that are not controlled within the range, the oxidation resistance and wear resistance are not sufficient, so that they are relatively short due to chipping, chipping, peeling, etc. It is clear that the service life is reached in time.

As described above, the surface-coated tool of the present invention has a particle size composition control layer (Ti _{1) on the} outermost surface directly or via an intermediate layer on a tool substrate made of cemented carbide sintered body or high-speed steel. _-X Al _x ) (N _1-y O _y ) is a hard coating layer having a layer thickness of 0.3 to 5.0 μm, and the Al content ratio x in the film cross section of the particle size composition control layer Exists in a range of 0.1 to 0.6, and a layered Ti high content region in which the value of x is 0.2 or less, and a layered Al height in which the value of x is 0.3 or more. At least one or more of the contained regions are included in the grain size composition control layer, the aspect ratio A of the crystal grains in the Ti-rich region is 1 to 5, and the crystal grains in the Al-rich region are Aspect ratio B of 10 to 70 provides excellent lubricity and excellent oxidation resistance In addition, this excellent oxidation resistance maintains high wear resistance over a long period of time even in wet high speed deep hole drilling conditions.

Claims (4)

On the drill body consisting of a cemented carbide sintered body or high speed steel, directly or through an intermediate layer, as the particle size composition control layer on the outermost surface _{(Ti 1-x Al x)} (N 1-y O y) In the surface coating tool in which a hard coating layer having a layer thickness of 0.3 to 5.0 μm consisting of the following components is present:
(A) The value of the Al content ratio x in the particle size composition control layer is
A range of 0.1 to 0.6, and a layered high Ti content region in which the value of x is 0.2 or less, and a layered high Al content region in which the value of x is 0.3 or more , At least one layer in each of the particle size composition control layers, and
(B) The aspect ratio A of the crystal grains in the high Ti content region is 1 to 5, and
(C) The aspect ratio B of the crystal grains in the high Al content region is 10 to 70, and
(D) the oxygen content ratio y is present between 0 and 0.08, and
(E) The minimum value of y in the high Al content region is 0.04 to 0.08, and the maximum value of y in the high Ti content region is less than 0.03. A surface-coated tool that maintains high oxidation resistance and wear resistance. The thickness XTi of the _Ti- rich region is in a range of 30 to 200 nm, and the thickness XAl of the _Al- rich region is in a range of 30 to 200 nm. The surface-coated tool described.   The intermediate layer is a hard coating layer having a layer thickness of 0.5 to 2.0 μm made of carbide, nitride, or carbonitride of one or two elements selected from Ti, Al, and Cr. The surface-coated tool according to claim 1 or 2, characterized in that The tool base is a drill base, and X _Ti in the drill margin portion gradually increases from the drill tip to a region of 5 times the outer diameter of the drill, and X _Al in the drill margin portion increases from the drill tip. The surface-coated drill according to any one of claims 1 to 3, wherein the surface-coated drill gradually decreases over a region up to a distance of 5 times the outer diameter of the drill.