JP2011240436A - Surface coated cutting tool excellent in heat resistance and fusion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool in which a hard coating layer exhibits excellent heat resistance and fusion resistance at the high-speed cutting of a hardly machinable material having high hardness.SOLUTION: The surface coated cutting tool having a hard coating layer formed on the surface of the tool base body is composed of followings (a) and (b): (a) a lower layer composed of a composite nitride layer of Al and Cr (and M) that satisfies a composition formula: (AlCrM)N (where, M denotes one or two kinds or more of added components selected from elements Si, B, Y of 4a, 5a, 6a groups in periodic tables except for Al, and α and β are in a range of 0.45≤α≤0.75 and 0.01≤β≤0.25, respectively, in an atomic ratio); and (b) an upper layer composed of a composite nitride layer of Nb and Y that satisfies a composition formula:(NbY)N (where, and γ is in a range of 0.01≤γ≤0.15 in an atomic ratio).

Description

  The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool). More specifically, for example, a high-hardness hard-to-cut material such as a Ti alloy, high-hardness stainless steel, or Ni-base heat-resistant alloy is cut with high heat generation. The present invention relates to a coated tool that exhibits excellent heat resistance and welding resistance with a hard coating layer when cutting is performed under high-speed conditions in which a large mechanical load is applied to the blade portion.

  Generally, coated tools are used for throwaway inserts that are detachably attached to the tip of cutting tools for drilling and cutting of various materials such as steel and cast iron. There are drills and miniature drills used, as well as solid type end mills used for chamfering, grooving and shoulder machining of work materials, etc. A slow-away end mill tool that performs cutting is known.

  As the coated tool, for example, a composite nitride ((Al, Cr) N) layer of Al and Cr on the surface of the tool base, or further, Si, B, Y, Zr, V, etc. (M component) Also known is a coated tool provided with a composite nitride (hereinafter collectively referred to as (Al, Cr, M) N) containing Al and Cr as a main component containing a trace amount of In particular, Ti, which is a constituent component, provides high-temperature hardness and heat resistance, and Al provides high-temperature strength, so that the (Al, Cr) N layer or (Al, Cr, M) N layer has excellent high-temperature strength. It is also known to show fracture resistance and wear resistance.

  Furthermore, the conventional coated tool is loaded with a tool base 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. Arc discharge is performed between the cathode electrode in which an alloy corresponding to the composition of the hard coating layer is set, for example, an Al-Cr-M alloy, and the anode electrode under the condition of current: 90A. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to create a reaction atmosphere of, for example, 2 Pa. On the other hand, the tool substrate is applied with a bias voltage of, for example, −100 V on the surface of the tool substrate. It is also known that it is produced by vapor-depositing a hard coating layer comprising an (Al, Cr, M) N layer.

JP 9-41127 A Japanese Patent Laid-Open No. 10-25566 JP 2004-106183 A JP 2004-269985 A Japanese Patent Laying-Open No. 2005-330539 JP 2006-82209 A

  However, in recent years, the FA of cutting machines has been remarkable. On the other hand, there has been a strong demand for labor saving and energy saving and further cost reduction for cutting, and as a result, cutting tools have as much influence on the type of work material as possible. However, in the above-mentioned conventional coated tools, this is a Ti alloy, high-hardness stainless steel, Ni-base heat-resistant. There is no problem when it is used for cutting hard hard-to-cut materials such as alloys at normal cutting speeds. However, these materials have high heat generation and a high load is locally applied to the cutting edge. When cutting under high-speed conditions, the work material and chips are heated to a high temperature due to the heat generated during cutting, and the viscosity increases. As a result, the weldability to the hard coating layer surface further increases. Chipping (minute chipping) in the results the cutting edge increases rapidly, which is at present, leading to a relatively short time service life due.

  Therefore, a technical problem to be solved by the present invention, that is, an object of the present invention is to provide a coated tool that exhibits excellent heat resistance and welding resistance even when cutting under high-speed conditions with high heat generation. It is.

  Therefore, the present inventors, from the viewpoint as described above, especially when cutting hard hard-to-cut materials such as Ti alloy, high-hardness stainless steel, Ni-base heat-resistant alloy, under high-speed cutting conditions, In order to develop a coated tool that has both excellent heat resistance and excellent welding resistance, the hard coating layer is a hard coating layer of a conventional coated carbide tool as a result of intensive research focusing on the conventional coated tool ( An Al, Cr) N layer or an (Al, Cr, M) N layer is formed as a lower layer with an average layer thickness of 0.5 to 5 μm, and an upper layer on top of this is formed by the amount of Y occupying the total amount with Nb. When a composite nitride layer of Nb and Y containing the Y component so that the content ratio is 1 to 15 atomic% (hereinafter referred to as (Nb, Y) N layer) is formed, the lower layer (Al, Cr) N layer or (Al, Cr, M) N layer has excellent high temperature hardness and high It shows strength and heat resistance, and the (Nb, Y) N layer, which is the upper layer, shows excellent welding resistance, but in particular, it depends on the Y component contained in the (Nb, Y) N layer of the upper layer. Since the high-temperature hardness of the (Nb, Y) N layer is improved, the excellent welding resistance of the (Nb, Y) N layer is maintained even in cutting with high heat generation. In high-speed cutting of materials, even if the cutting edge becomes hot, it has excellent resistance to welding with the work material, and as a result, the occurrence of chipping (small chipping) in the cutting edge is suppressed, and for a long time The inventors have obtained new knowledge that excellent wear resistance is exhibited, and have completed the present invention based on such knowledge.

The present invention has been made based on the research results,
“(1) In a surface-coated cutting tool in which a hard coating layer is formed on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.5-5 μm, and
A composite nitride of Al and Cr that satisfies the composition formula: (Al _1-α Cr _α ) N (where α is the Cr content ratio, and the atomic ratio is 0.45 ≦ α ≦ 0.75). A lower layer consisting of layers,
(B) having an average layer thickness of 1-5 μm, and
Nb and Y composite nitride satisfying the composition formula: (Nb _1-γ Y _γ ) N (where γ represents the content ratio of Y and the atomic ratio is 0.01 ≦ γ ≦ 0.15) A surface-coated cutting tool comprising an upper layer composed of layers.
(2) In a surface-coated cutting tool formed by forming a hard coating layer on the surface of a tool base composed of a tungsten carbide-based cemented carbide or a titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.5-5 μm, and
Composition formula: (Al _1-α-β Cr _α M _β ) N (where M is selected from the elements of groups 4a, 5a and 6a of the periodic table excluding Al, Si, B and Y) Species or two or more additional components, α represents the Cr content, β represents the M content, and atomic ratios of 0.45 ≦ α ≦ 0.75 and 0.01 ≦ β ≦ A lower layer composed of a composite nitride layer of Al, Cr, and M satisfying 0.25),
(B) having an average layer thickness of 1-5 μm, and
Nb and Y composite nitride satisfying the composition formula: (Nb _1-γ Y _γ ) N (where γ represents the content ratio of Y and the atomic ratio is 0.01 ≦ γ ≦ 0.15) A surface-coated cutting tool comprising an upper layer composed of layers. "
It is characterized by.

  Next, the reason why the numerical values of the constituent layers of the hard coating layer of the coated tool of the present invention are limited as described above will be described.

(A) Lower layer composition and average layer thickness The (Al, Cr) N layer or (Al, Cr, M) N layer constituting the lower layer has a high hardness in the hard coating layer for the Cr component. The Al component has the effect of improving the high-temperature strength. Further, among the M components, elements of the periodic tables 4a, 5a and 6a excluding Al, Si and B, have a hard coating layer. Y has the effect of improving wear resistance, and Y has the effect of improving the high temperature oxidation resistance of the hard coating layer, but the α value indicating the ratio of Cr is the total amount of Al or the total amount of Al and M. If the ratio to the amount (atomic ratio, the same applies hereinafter) is less than 0.45, the predetermined high-temperature hardness cannot be secured, which causes a decrease in wear resistance, while the α value indicating the ratio of Cr If the value exceeds 0.75, the Al content will be relatively reduced and high speed cutting will occur. The high temperature strength required for processing cannot be ensured, it becomes difficult to prevent the occurrence of chipping, and the β value indicating the content ratio of the M component accounts for the total amount of Al and Cr ( If the atomic ratio is less than 0.01, the improvement in properties such as wear resistance and high-temperature oxidation resistance due to the inclusion of the M component cannot be expected, while if the β value exceeds 0.25, Since a decreasing tendency appears in the high-temperature strength, the α value was set to 0.45 to 0.75, and the β value was set to 0.01 to 0.25.

  On the other hand, if the average layer thickness is less than 0.5 μm, it is insufficient to exhibit its excellent wear resistance over a long period. On the other hand, if the average layer thickness exceeds 5 μm, the high-speed cutting is performed. Then, since chipping is likely to occur in the cutting edge portion, the average layer thickness is set to 0.5 to 5 μm.

(B) Composition of the upper layer The Nb and Y composite nitride (hereinafter abbreviated as (Nb, Y) N) layer constituting the upper layer has predetermined heat resistance, high temperature strength, and welding resistance, The component Y component provides excellent high-temperature hardness. Therefore, a low friction coefficient is maintained even under high-temperature cutting conditions, and excellent welding resistance is exhibited. When the γ value indicating the ratio is less than 0.01 in the ratio to the total amount with Nb (atomic ratio, the same shall apply hereinafter), the heat resistance cannot be ensured, so the anti-welding effect cannot be expected, On the other hand, if the γ value indicating the ratio of Y exceeds 0.15, the content ratio of Nb is relatively decreased, and it is possible to ensure the high temperature strength required for high-speed cutting of a hard hard material. Not only is it impossible, but also the welding resistance is reduced, preventing chipping. Since Rukoto becomes difficult, it was defined as the γ value from 0.01 to 0.15 (atomic ratio, hereinafter the same).

(C) Average layer thickness of the upper layer If the average layer thickness of the (Nb, Y) N layer constituting the hard coating layer is less than 1 μm, it will exhibit its excellent heat resistance and welding resistance over a long period of time. On the other hand, if the average layer thickness exceeds 5 μm, chipping is likely to occur at the cutting edge in high-speed cutting of hard hard-to-cut materials such as Ti alloy, Ni-base heat-resistant alloy, and high-hardness stainless steel. Therefore, the average layer thickness was determined to be 1 to 5 μm.

The (Al, Cr) N layer, (Al, Cr, M) N layer, or (Nb, Y) N layer is, for example, an arc that is a kind of physical vapor deposition apparatus schematically shown in FIG. A cathode electrode made of an Al—Cr alloy or Al—Cr—M alloy having a predetermined composition in the apparatus while the substrate is loaded into the ion plating apparatus and the apparatus is heated to a temperature of, for example, 500 ° C. with a heater. (Evaporation source) and a cathode electrode (evaporation source) made of an Nb-Y alloy having a predetermined composition are arranged, and an anode electrode and a cathode electrode (evaporation source) made of an Al-Cr alloy or an Al-Cr-M alloy In the meantime, for example, arc discharge is generated under the condition of current: 90 A, and simultaneously, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa, for example. of By vapor deposition under the condition of applying a bias voltage, an (Al, Cr) N layer or (Al, Cr, M) layer is first deposited as a lower layer, and then between the Nb-Y alloy cathode electrode and the anode electrode. In addition, by generating arc discharge as described above, an upper layer composed of (Nb, Y) N layers can be formed by vapor deposition.

  According to the coated tool of the present invention, the lower (Al, Cr) N layer or (Al, Cr, M) N layer constituting the hard coating layer has excellent high temperature hardness, heat resistance, and high temperature strength. In addition, it has excellent wear resistance and high-temperature oxidation resistance, and the (Nb, Y) N layer of the upper layer has excellent heat resistance and welding resistance, so that it has a hard coating. The layer as a whole has excellent high-temperature hardness, heat resistance, high-temperature strength, etc., as well as excellent welding resistance. As a result, the layer is particularly high in Ti alloys, high-hardness stainless steel, Ni-base heat-resistant alloys, etc. Even a hard-to-cut material with high heat generation and high-speed cutting with high load exhibits excellent welding resistance and exhibits excellent wear resistance over a long period of time.

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

  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, and after sintering, tool bases A-1 to A-10 made of WC-based cemented carbide with ISO standard / CNMG120408 chip shape were formed. .

In addition, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, mix these raw material powders into the composition shown in Table 2, wet mix for 24 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure Then, the green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base B made of TiCN-based cermet having an ISO standard / CNMG120408 chip shape was obtained. -1 to B-6 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 apparatus shown in FIG. It is mounted along the outer periphery at a position that is a predetermined distance in the radial direction from the central axis on the inner rotary table, and cathode electrodes (evaporation sources) are arranged on both sides facing each other across the rotary table. Has an Al-Cr alloy or Al-Cr-M alloy for forming a lower layer having a predetermined composition as a cathode electrode (evaporation source), and an upper layer having a predetermined composition is formed as a cathode electrode (evaporation source) on the other side. Nb-Y alloy for
(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 DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the Al—Cr—M alloy for forming the lower layer of the cathode electrode and the anode electrode, thereby causing the surface of the tool base to be in contact with the Al surface. -Bombard cleaning with Cr alloy or Al-Cr-M alloy,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and A current of 120 A is passed between the Al—Cr alloy or Al—Cr—M alloy of the cathode electrode and the anode electrode to generate an arc discharge. Table 3 and Table 4 show the surface of the tool base. After the (Al, Cr) N layer or (Al, Cr, M) N layer as the lower layer having the target composition and target layer thickness is formed by vapor deposition with an average layer thickness of 0.5 to 5 μm, the Al—Cr alloy or The arc discharge between the cathode electrode (evaporation source) of the Al—Cr—M alloy and the anode electrode is stopped,
(D) Subsequently, an arc discharge is generated by flowing a current of 120 A between the Nb—Y alloy electrode, which is the cathode electrode (evaporation source), and the anode electrode while maintaining the atmosphere in the apparatus in a nitrogen atmosphere of 2 Pa. Then, the (Nb, Y) N layer having the target layer thickness shown in Tables 3 and 4 is formed by vapor deposition.
Hard coating layers were formed by vapor deposition according to the above (a) to (d), and surface-coated throwaway tips (hereinafter referred to as the present invention-coated tips) 1 to 39 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, respectively, and the arc ion plating shown in FIG. The apparatus was charged and an Al—Cr alloy or Al—Cr—M alloy having a predetermined composition was mounted as a cathode electrode (evaporation source). First, while evacuating the apparatus and maintaining 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 was applied to the tool base, and 100 A was applied between the Al—Cr alloy or Al—Cr—M alloy of the cathode electrode and the anode electrode. The surface of the tool base is bombarded with the Al—Cr alloy or Al—Cr—M alloy, and then a nitrogen gas is added as a reaction gas in the apparatus. Introducing a gas to a reaction atmosphere of 3 Pa, lowering a bias voltage applied to the tool base to −100 V, and generating an arc discharge between each cathode electrode and anode electrode of the predetermined composition, On the surface of each of the tool bases A-1 to A-10 and B-1 to B-6, the (Al, Cr) N layer having the target composition and the target layer thickness shown in Tables 5 and 6 or (Al, Surface-coated throwaway tips (hereinafter referred to as comparative coated tips) 1 to 16 as comparative coated tools were produced by vapor-depositing a hard coating layer composed of a Cr, M) N layer.

Next, in the state where each of the various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1 to 39 and the comparative coated chips 1 to 16 are as follows:
Work material: Ti-6Al-4V alloy (HB400) round bar,
Cutting speed: 45 m / min. ,
Incision: 2 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes,
Wet continuous high-speed cutting test of Ti alloy under the following conditions (cutting condition A) (normal cutting speed and feed are 30 m / min. And 0.15 mm / rev., Respectively),
Work material: JIS / SUS630 (HB370) round bar,
Cutting speed: 100 m / min. ,
Cutting depth: 3 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes,
Wet continuous high-speed cutting test of high hardness stainless steel under the following conditions (cutting condition B) (normal cutting speed and feed are 90 m / min. And 0.2 mm / rev., Respectively),
Work material: A round bar of Ni-18Cr-3Mo-18.5Fe-0.9Ti-1.0 (Nb + Ta) -0.5Al (HB450),
Cutting speed: 40 m / min. ,
Cutting depth: 3 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes,
Wet continuous high-speed cutting test of Ni-base heat-resistant alloy under the following conditions (cutting condition C) (normal cutting speed and feed are 30 m / min. And 0.15 mm / rev., Respectively),
The flank wear width of the cutting edge was measured in any high-speed cutting test. The measurement results are shown in Tables 7 and 8.

As in Example 1, all of WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder having an average particle diameter of 1 to 3 μm. The raw material powder is 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. , Temperature: Sintered at 1400 ° C. for 1 hour to form a round tool sintered body for forming a tool base having a diameter of 13 mm. WC-base cemented carbide tool bases (end mills) A-1 to A-10 having a diameter of 10 mm × 22 mm and a four-blade square shape with a twist angle of 30 degrees were manufactured.

  Then, the surfaces of these tool bases (end mills) A-1 to A-10 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, the (Al, Cr) N layer or (Al, Cr, M) N layer having the target composition and target layer thickness shown in Table 10 and the target layer thickness also shown in Table 10 are used. By subjecting a hard coating layer composed of (Nb, Y) N layer to vapor deposition, surface coated carbide end mills (hereinafter referred to as the present coated end mills) 1 to 27 as the present coated tools were produced, respectively. .

  For comparison purposes, the surfaces of the tool bases (end mills) A-1 to A-10 are ultrasonically cleaned in acetone and dried, and then loaded into the arc ion plating apparatus shown in FIG. Then, a hard coating layer made of an (Al, Cr) N layer or (Al, Cr, M) N layer having the target composition and target layer thickness shown in Table 10 is deposited under the same conditions as in the first embodiment. Thus, surface coated carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 10 as comparative coated tools were produced, respectively.

Next, for the present invention coated end mills 1-27 and comparative coated end mills 1-10,
Work material—planar dimensions: 100 mm × 250 mm, thickness: 50 mm Ti-6Al-4V alloy (HB400) plate material,
Cutting speed: 40 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 100 mm / min,
Wet high-speed grooving test of Ti alloy under the following conditions (cutting condition D) (normal cutting speed and table feed are 30 m / min. And 80 mm / min, respectively),
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS630 (HB370) plate material,
Cutting speed: 110 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 220 mm / min,
Wet high-speed grooving test of high hardness stainless steel under the conditions (cutting condition D) (normal cutting speed and table feed are 90 m / min. And 200 mm / min, respectively),
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm Ni-18Cr-3Mo-18.5Fe-0.9Ti-1.0 (Nb + Ta) -0.5Al (HB450) plate material,
Cutting speed: 40 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 100 mm / min,
Wet high-speed grooving test of Ni-base heat-resistant alloy under the following conditions (cutting condition D) (normal cutting speed and table feed are 30 m / min. And 80 mm / min, respectively)
In each high-speed 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 9 and Table 10, respectively.

  The round bar sintered body with a diameter of 13 mm manufactured in Example 2 was used, and from this round bar sintered body, the dimensions of the groove forming part diameter × length were 8 mm × 22 mm and the twist angle by grinding. WC-base cemented carbide tool bases (drills) A-1 to A-10 having a 30-degree two-blade shape were produced, respectively.

  Next, the cutting edges of these tool bases (drills) A-1 to A-10 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. The (Al, Cr) N layer or the (Al, Cr, M) N layer having the target composition and target layer thickness shown in Table 11 under the same conditions as in Example 1, and also shown in Table 11 The hard coating layer composed of the (Nb, Y) N layer having the target composition and the target layer thickness is formed by vapor deposition, so that the surface-coated carbide drill of the present invention as the coated tool of the present invention (hereinafter referred to as the present coated drill). ) 1-27 were produced respectively.

  For the purpose of comparison, honing is performed on the surfaces of the tool bases (drills) A-1 to A-10, ultrasonic cleaning is performed in acetone, and the arc ion plate shown in FIG. A hard coating comprising an (Al, Cr) N layer or (Al, Cr, M) N layer having the target composition and target layer thickness shown in Table 12 under the same conditions as in Example 1 Surface-coated cemented carbide drills (hereinafter referred to as comparative coated drills) 1 to 10 as comparative coated tools were produced by forming layers by vapor deposition.

Next, for the present invention coated drills 1-27 and comparative coated drills 1-10,
Work material—planar dimensions: 100 mm × 250 mm, thickness: 50 mm Ti-6Al-4V alloy (HB400) plate material,
Cutting speed: 40 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 5 mm,
Wet high-speed drilling test of Ti alloy under the following conditions (cutting condition G) (normal cutting speed and feed are 30 m / min. And 0.1 mm / rev., Respectively),
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS630 (HB370) plate material,
Cutting speed: 80 m / min. ,
Feed: 0.25 mm / rev,
Hole depth: 5 mm,
Wet high-speed drilling test of high hardness stainless steel under the conditions (cutting condition H) (normal cutting speed and feed are 60 m / min. And 0.15 mm / rev., Respectively),
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm Ni-18Cr-3Mo-18.5Fe-0.9Ti-1.0 (Nb + Ta) -0.5Al (HB450) plate material,
Cutting speed: 40 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 5 mm,
Wet high-speed drilling test of Ni-base heat-resistant alloy under the following conditions (cutting condition I) (normal cutting speed and feed are 30 m / min. And 0.1 mm / rev., Respectively),
In each wet high-speed 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 Tables 11 and 12, respectively.

  (Al, Cr) N layer constituting the hard coating layer of the present coated chips 1 to 39, the present coated end mills 1 to 27, and the present coated drills 1 to 27 as the present coated tool obtained as a result Composition of (Al, Cr, M) N layer (lower layer) and (Nb, Y) N layer (upper layer), comparative coated tips 1-16 as comparative coated tools, comparative coated end mills 1-10, and The composition of the hard coating layer comprising the (Al, Cr) N layer or (Al, Cr, M) N layer of the comparative coated drills 1 to 10 was measured by energy dispersive X-ray analysis using a transmission electron microscope. However, each showed substantially the same composition as the target composition.

  Moreover, when the average layer thickness of each layer which comprises the said hard coating layer was cross-sectional measured using the scanning electron microscope, all showed the average value (average value of five places) substantially the same as target layer thickness.

  From the results shown in Tables 7 to 12, the coated tool of the present invention is the lower layer of the hard coating layer, especially in high-speed cutting of hard hard-to-cut materials such as Ti alloy, high-hardness stainless steel, and Ni-base heat-resistant alloy. (Al, Cr) N layer or (Al, Cr, M) N layer, which is firmly bonded to the surface of the tool substrate, has excellent high temperature hardness, heat resistance, high temperature strength, or in addition to this Further, the upper layer composed of the (Nb, Y) N layer having excellent wear resistance, high-temperature oxidation resistance and excellent heat resistance provides excellent welding resistance between the work material and the chips. As a result, the hard coating layer (Al, Cr) N layer or (Al, Cr, M) has excellent wear resistance over a long period of time without occurrence of chipping. A ratio composed of N layers and not including (Nb, Y) N layers In the coated tool, since the adhesiveness and reactivity between the work material (difficult-to-cut material) and the chips and the hard coating layer are further increased in the high-speed cutting of the work material, It is clear that chipping occurs and the service life is reached in a relatively short time.

  As described above, the coated tool of the present invention is capable of cutting not only general work materials, but also high-speed cutting of hard materials difficult to cut such as Ti alloy, high hardness stainless steel, Ni-base heat-resistant alloy. However, it exhibits excellent wear resistance and welding resistance, and exhibits excellent cutting performance over a long period of time. Therefore, FA of cutting equipment, labor saving and energy saving of cutting, and cost reduction It is possible to cope with the above sufficiently.

Claims (2)

In a surface-coated cutting tool formed by forming a hard coating layer on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.5-5 μm, and
A composite nitride of Al and Cr that satisfies the composition formula: (Al _1-α Cr _α ) N (where α is the Cr content ratio, and the atomic ratio is 0.45 ≦ α ≦ 0.75). A lower layer consisting of layers,
(B) having an average layer thickness of 1-5 μm, and
Nb and Y composite nitride satisfying the composition formula: (Nb _1-γ Y _γ ) N (where γ represents the content ratio of Y and the atomic ratio is 0.01 ≦ γ ≦ 0.15) A surface-coated cutting tool comprising an upper layer composed of layers. In a surface-coated cutting tool formed by forming a hard coating layer on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.5-5 μm, and
Composition formula: (Al _1-α-β Cr _α M _β ) N (where M is selected from the elements of groups 4a, 5a and 6a of the periodic table excluding Al, Si, B and Y) Species or two or more additional components, α represents the Cr content, β represents the M content, and atomic ratios of 0.45 ≦ α ≦ 0.75 and 0.01 ≦ β ≦ A lower layer composed of a composite nitride layer of Al, Cr, and M satisfying 0.25),
(B) having an average layer thickness of 1-5 μm, and
Nb and Y composite nitride satisfying the composition formula: (Nb _1-γ Y _γ ) N (where γ represents the content ratio of Y and the atomic ratio is 0.01 ≦ γ ≦ 0.15) A surface-coated cutting tool comprising an upper layer composed of layers.

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