JP2006224223A - Cutting tool made of surface covered cemented carbide with hard covering layer displaying excellent abrasion resistance in high speed cutting work of heat resisting alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool made of surface covered cemented carbide a hard covering layer of which displays excellent abrasion resistance in high speed cutting work of heat resisting alloy. <P>SOLUTION: This cutting tool made of surface covered cemented carbide is made forming the hard covering layer, on the surface of a carbide substrate by vapor deposition, which is constituted of (a) an upper layer and a lower layer both of which are made of (Cr, Al, B)N, the upper layer which has average layer thickness of 0.5 to 1.5μm and the lower layer which has average layer thickness of 2 to 6μm respectively, (b) the upper layer which has an alternately laminated structure of a thin layer A and a thin layer B single layer average layer thickness of both of which is respectively 5 to 20n (nanometer), the thin layer A and B which are constituted of a (Cr, Al, B)N layer to satisfy a specific composition formula, and (c) the lower layer which has a single phase structure and is made of the (Cr, Al, B)N layer to satisfy a composition formula: [<SB>Cr1-(X+Y)</SB>Al<SB>X</SB>B<SB>Y</SB>]N (but X shows 0.50 to 0.70 and Y shows 0.005 to 0.05 in an atomic ratio). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, the hard coating layer has excellent thermal conductivity, and in addition to high-temperature hardness and high-temperature strength, it also has high-temperature oxidation resistance, and therefore, particularly Ni alloys and Co alloys with high heat generation, The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated carbide tool) that exhibits excellent wear resistance when used for high-speed cutting of a heat-resistant alloy such as a Ti alloy.

  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.

In addition, as a coated carbide tool, a single-phase structure is formed on the surface of a cemented carbide substrate made of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. Have and
Composition formula: [Cr _1-X Al _X ] N (wherein X is 0.50 to 0.70 in atomic ratio),
Coated carbide tools formed by vapor-depositing a hard coating layer composed of a composite nitride of Cr and Al [hereinafter referred to as (Cr, Al) N] layer satisfying the requirements with an average layer thickness of 2 to 8 μm are known. In such a conventional coated carbide tool, the (Cr, Al) N layer constituting the hard coating layer is hard at high temperature due to Al as a constituent component, high temperature strength due to the Cr, and coexistence of Cr and Al. Excellent wear resistance even when used for cutting heat-resistant alloys such as Ni alloys, Co alloys, and Ti alloys that generate relatively high heat during cutting. It is also known to show.

Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, a cathode electrode (evaporation source) in which a Cr—Al alloy having a composition corresponding to the composition of the (Cr, Al) N layer, which is a hard coating layer, is heated to a temperature of 500 ° C. and an anode electrode. 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 obtain a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate has a bias of, for example, −100 V It is also known that it is produced by vapor-depositing a hard coating layer composed of the (Cr, Al) N layer on the surface of the cemented carbide substrate under the condition of applying a voltage.
Japanese Patent No. 3027502

  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 a coated carbide tool, when it is used for cutting a heat-resistant alloy such as a Ni alloy or a Co alloy with a relatively high heat generation during cutting, or a Ti alloy under normal cutting conditions, the above The cutting edge part has a normal normal wear form, and there is no problem and exhibits a predetermined wear resistance. Especially, the cutting process of the heat-resistant alloy is performed under a high-speed cutting process condition with higher heat generation. When used to perform, the (Cr, Al) N layer, which is a hard coating layer, undergoes thermoplastic deformation that causes uneven wear, and as a result, the progress of wear is significantly accelerated. Short service life The it is the status quo.

In view of the above, the present inventors have developed the above-mentioned conventional coating in order to develop a coated carbide tool exhibiting excellent wear resistance with a hard coating layer particularly in high-speed cutting of the above heat-resistant alloy. As a result of conducting research by focusing on the (Cr, Al) N layer that constitutes the hard coating layer of carbide tools,
(A) In the (Cr, Al) N layer constituting the conventional hard coating layer, a B component is added to this, and a composite nitride of Cr, Al and B (boron) [hereinafter referred to as (Cr, Al, B) indicated as N], the thermal conductivity of the layer is improved in proportion to the content of the B component, and the layer exhibits an excellent heat removal effect. However, the conventional (Cr, Al) The N layer has excellent high-temperature hardness and high-temperature oxidation resistance, and the proportion that can be contained without impairing the high-temperature strength is at most about 0.5 to 5 atomic%. The high thermal conductivity required for high-speed cutting cannot be ensured, and in order to satisfy these requirements satisfactorily, 20-35 atomic% of B, far exceeding the above 0.5-5 atomic%. Containment, while containing 20-35 atomic% B component (Cr, Al, ) In order to use the N layer as a hard coating layer for practical use, it is necessary to contain a predetermined amount of Cr to ensure a predetermined high-temperature strength. In this case, the content ratio of the Al component is extremely low. Inevitable, this results in extremely low high temperature hardness and high temperature oxidation resistance.

(B) In the (Cr, Al, B) N layer of (a) above, the B content is extremely high, while the B content is increased, the Al content is decreased,
Composition formula: [Cr _{1− (E + F)} Al _E B _F ] N (wherein E is 0.01 to 0.06 and F is 0.20 to 0.35 in atomic ratio) (Cr , Al, B) N layer;
Al content ratio is relatively high, while B content ratio is relatively low,
_{Formula: [Ti 1- (M + N} ) Al M B N] N ( provided that an atomic ratio, M is 0.25 to 0.40, N denotes the 0.05 to 0.15) satisfies (Cr , Al, B) N layer,
Are alternately laminated in a state where each layer has an average layer thickness of 5 to 20 nm (nanometers), and in the resultant (Cr, Al, B) N layer, the above-mentioned thin layer is alternately laminated. Therefore, the excellent thermal conductivity of the (Cr, Al, B) N layer (hereinafter referred to as the thin layer A) having a high B content and a relatively low B content ratio, and a correspondingly high Al content ratio. The (Cr, Al, B) N layer (hereinafter referred to as the thin layer B) has a predetermined relatively high high-temperature hardness.
It has excellent thermal conductivity due to the high B-containing thin layer A and relatively high high-temperature hardness and high-temperature oxidation resistance due to the high Al-containing thin layer B.

(C) The (Cr, Al, B) N layer having the alternate layered structure of the thin layer A and the thin layer B of (b) above has excellent thermal conductivity and a predetermined value required for high-speed cutting of a heat-resistant alloy. However, it does not have a sufficiently satisfactory high temperature hardness and high temperature oxidation resistance, so it is provided as an upper layer of the hard coating layer, while Although the conductivity is insufficient, the content ratio of the Al component is relatively high, and the conventional hard coating layer (a) having excellent high-temperature hardness and high-temperature oxidation resistance is formed (Cr, Al) (Ti, Al, B) N layer containing B component in a proportion of 0.5 to 5 atomic% in the N layer, that is,
Composition _{formula: [Cr 1- (X + Y} ) Al X B Y] N ( provided that an atomic ratio, X is 0.50 to 0.70, Y denotes a 0.005 to 0.05) satisfies the single (Cr, Al, B) N layer of single phase structure,
The resulting hard coating layer has high temperature hardness and high temperature oxidation resistance in addition to excellent thermal conductivity. Carbide tools should exhibit excellent wear resistance over a long period of time without the occurrence of thermoplastic deformation that causes uneven wear, even in high-speed cutting of heat-resistant alloys with high heat generation.
The research results shown in (a) to (c) above were obtained.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) Both are composed of an upper layer and a lower layer made of (Cr, Al, B) N, the upper layer has an average layer thickness of 0.5 to 1.5 μm, and the lower layer has an average layer thickness of 2 to 6 μm. And
(B) Each of the upper layers has an alternate layered structure of thin layers A and thin layers B each having an average layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
Composition formula: [Cr _{1− (E + F)} Al _E B _F ] N (wherein E is 0.01 to 0.06 and F is 0.20 to 0.35 in atomic ratio) (Cr , Al, B) N layer,
The thin layer B is
Composition _{formula: [Cr 1- (M + N} ) Al M B N] N ( provided that an atomic ratio, M is 0.25 to 0.40, N denotes the 0.05 to 0.15) satisfies (Cr , Al, B) N layer,
(C) the lower layer has a single phase structure;
Composition _{formula: [(Cr 1- (X +} Y) Al X B Y] N ( provided that an atomic ratio, X is 0.50 to 0.70, Y satisfies the showing the 0.005 to 0.05) ( Cr, Al, B) N layer,
It is characterized by a coated carbide tool that exhibits excellent wear resistance in high-speed cutting of a heat-resistant alloy formed by vapor-depositing a hard coating layer made of

Next, the reason why the numerical values of the hard coating layer of the coated carbide tool of the present invention are limited as described above will be described.
(A) Composition formula and average layer thickness of the lower layer As described above, the (Cr, Al, B) N layer constituting the hard coating layer improves the high temperature hardness for the Al component and the high temperature strength for the Cr component. At the same time, the high-temperature oxidation resistance is improved in the state where Al and Cr coexist, and the B component has the effect of improving the thermal conductivity. In the lower layer, the content ratio of the Al component is relatively increased. While maintaining high high-temperature hardness and high-temperature oxidation resistance, if the X value indicating the Al content is less than 0.50 in terms of the total amount of Cr and B (atomic ratio, the same shall apply hereinafter), the desired excellent High temperature hardness and high temperature oxidation resistance cannot be ensured, and wear progresses rapidly. On the other hand, if the X value indicating the proportion of Al exceeds 0.70, the high temperature strength rapidly increases. As a result, chipping (slight chipping) is likely to occur. Therefore, the X value was set to 0.50 to 0.70.
Further, the Y value indicating the ratio of B is the ratio of the total amount of Cr and Al, and if it is less than 0.005, the predetermined thermal conductivity cannot be ensured, while the Y value exceeds 0.05. Then, since a clear decreasing tendency appears in the high temperature strength, the Y value was set to 0.005 to 0.05.
Furthermore, if the average layer thickness is less than 2 μm, the excellent high-temperature hardness and high-temperature oxidation resistance cannot be imparted to the hard coating layer over a long period of time, resulting in a short tool life, while the average layer thickness is If it exceeds 6 μm, chipping is likely to occur. Therefore, the average layer thickness is set to 2 to 6 μm.

(B) Composition formula of upper layer thin layer A For the B component in (Cr, Al, B) N of the upper layer thin layer A, the content ratio is relatively increased as described above, and the thermal conductivity is increased. F, which has an effect of preventing the occurrence of thermoplastic deformation that causes uneven wear, by exhibiting an excellent heat removal effect in high-speed cutting of a heat-resistant alloy with high heat generation. Is a proportion of the total amount of Cr and Al, and if it is less than 0.20, the desired excellent effect cannot be ensured for the above action, whereas if the F value exceeds 0.35, the high-temperature strength rapidly increases. The F value was set to 0.20 to 0.35, because this causes a decrease in the high-temperature strength of the entire upper layer, and chipping tends to occur.
Further, the E value indicating the proportion of Al is the proportion of the total amount of Cr and B, and if it is less than 0.01, the minimum high-temperature hardness cannot be ensured, causing wear promotion, while the E When the value exceeds 0.06, the high-temperature strength is lowered, which causes chipping. Therefore, the E value is determined to be 0.01 to 0.06.

(C) Composition formula of thin layer B of the upper layer In the thin layer B of the upper layer, the content ratio of the B component is relatively low, and the content ratio of the Al component is maintained high by that amount. It has high high temperature hardness and high temperature oxidation resistance, reinforces the lack of high temperature hardness of the adjacent thin layer A, so that the excellent thermal conductivity of the thin layer A and the high temperature hardness of the thin layer B However, when the M value indicating the Al content in the composition formula is less than 0.25, the desired high-temperature hardness cannot be ensured. On the other hand, if the M value exceeds 0.40, the high temperature strength of the entire upper layer decreases and causes chipping. Therefore, the M value is set to 0.25 to 0.25. It was set to 0.40.
Further, if the N value indicating the ratio of B is a ratio of the total amount of Cr and Al, and less than 0.05, a decrease in the thermal conductivity of the entire upper layer is inevitable, while the N value is 0.15. If it exceeds the upper limit, the high-temperature strength suddenly decreases, so the N value was determined to be 0.05 to 0.15.

(D) Single layer average layer thickness of thin layer A and thin layer B of the upper layer If each layer average layer thickness is less than 5 nm, it is difficult to clearly form each thin layer with the above composition. The desired excellent thermal conductivity and predetermined high-temperature hardness and high-temperature oxidation resistance cannot be ensured for the layer, and the disadvantage of each thin layer when the average layer thickness of each layer exceeds 20 nm, that is, the thin layer If it is A, insufficient high-temperature hardness, and if it is a thin layer B, insufficient thermal conductivity appears locally in the layer, which makes it easier for chipping to occur and promotes the progress of wear. The average layer thickness of each layer was determined to be 5 to 20 nm.

(E) Average layer thickness of the upper layer When the average layer thickness is less than 0.5 μm, the hard coating layer is provided with long-term thermal conductivity, predetermined high temperature hardness and high temperature oxidation resistance. However, the tool life is shortened. On the other hand, if the average layer thickness exceeds 1.5 μm, chipping tends to occur. Therefore, the average layer thickness is set to 0.5 to 1.5 μm.

  In the coated carbide tool of the present invention, the hard coating layer is composed of the (Cr, Al, B) N layer, and the upper layer of the hard coating layer is excellent by adopting an alternate laminated structure of the thin layer A and the thin layer B. Ni with high heat generation, because it has thermal conductivity, predetermined high temperature hardness and high temperature oxidation resistance, and the lower layer of the single phase structure has excellent high temperature hardness and high temperature oxidation resistance. Even in high-speed cutting of heat-resistant alloys such as alloys, Co alloys, and Ti alloys, the hard coating layer exhibits an excellent heat removal effect, and as a result, there is no occurrence of thermoplastic deformation that causes uneven wear on the cutting edge. The blade portion takes a normal wear form and exhibits excellent wear resistance over a long period of time.

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

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C for 1 hour, after sintering, WC-based carbide with honing of R: 0.03 on the cutting edge and chip shape of ISO standard CNMG120408 Alloy carbide substrates 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. The carbide substrates B-1 to B-6 made of TiCN base cermet having the following chip shape were formed.

(A) Next, each of the above carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then the arc ion plate shown in FIG. Attached along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the coating apparatus, and used as a cathode electrode (evaporation source) on one side with the target compositions shown in Tables 3 and 4, respectively. As the upper layer Cr-Al-B alloy having the corresponding component composition and the cathode electrode (evaporation source) on the other side, the component compositions corresponding to the target compositions shown in Tables 3 and 4 are also used. A Cr-Al-B alloy for forming a thin layer B as an upper layer is disposed opposite to the rotary table, and a cathode is formed along the rotary table at a position shifted by 90 degrees from both the Cr-Al-B alloys. As an electrode (evaporation source) Similarly respectively mounted Cr-Al-B alloy for the lower layer formed having a component composition corresponding to the target composition shown in Tables 3 and 4,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then the carbide substrate that rotates while rotating on the rotary table is set to −1000 V. And applying a current of 100 A between the lower layer forming Cr—Al—B alloy and the anode electrode to generate an arc discharge, so that the surface of the cemented carbide substrate is covered with the Cr—Al— Bombarded with B alloy,
(C) Introducing nitrogen gas as a reaction gas into the apparatus to make a reaction atmosphere of 3 Pa, applying a DC bias voltage of −100 V to a carbide substrate rotating while rotating on the rotary table, and An arc discharge is generated by flowing a current of 100 A between the layer-forming Cr—Al—B alloy and the anode electrode, so that the target composition and target layer thickness shown in Tables 3 and 4 are formed on the surface of the cemented carbide substrate. (Cr, Al, B) N layer having a single phase structure is deposited as a lower layer of the hard coating layer,
(D) Next, the flow rate of nitrogen gas as a reaction gas introduced into the apparatus is adjusted to a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to the carbide substrate rotating while rotating on the rotary table. In the applied state, a predetermined current in a range of 50 to 100 A is passed between the cathode electrode and the anode electrode of the Cr-Al-B alloy for forming the thin layer A to generate arc discharge, and the carbide A thin layer A having a predetermined layer thickness is formed on the surface of the substrate. After the thin layer A is formed, the arc discharge is stopped, and instead, between the cathode electrode and the anode electrode of the Cr-Al-B alloy for forming the thin layer B Similarly, a predetermined current in the range of 50 to 100 A is applied to generate arc discharge to form a thin layer B having a predetermined thickness, and then the arc discharge is stopped (in this case, starting from the formation of the thin layer B). Or the thin layer A again. Formation of thin layer A by arc discharge between cathode and anode electrode of Cr-Al-B alloy for formation, and thinning by arc discharge between cathode electrode and anode electrode of Cr-Al-B alloy for formation of thin layer B The formation of the layer B is alternately repeated so that the thin layer A and the thin layer B having the target composition and the target layer thickness shown in Tables 3 and 4 along the layer thickness direction are alternately laminated on the surface of the cemented carbide substrate. An upper layer made of the same is formed by vapor deposition with an overall target layer thickness shown in Tables 3 and 4, and the surface-coated carbide throwaway tip (hereinafter referred to as the present invention coated carbide) as the present coated carbide tool. Chips) 1 to 16 were produced.

  For the purpose of comparison, these carbide substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plate shown in FIG. A Cr—Al alloy having a component composition corresponding to the target composition shown in Table 5 was mounted as a cathode electrode (evaporation source) as a cathode electrode (evaporation source). While maintaining the following vacuum, the inside of the apparatus was heated to 500 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and between the Cr—Al alloy of the cathode electrode and the anode electrode An arc discharge is generated by supplying a current of 100 A to the substrate, and the surface of the carbide substrate is bombarded with the Cr—Al alloy, and then nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 3 Pa. At the same time, the bias voltage applied to the cemented carbide substrate is lowered to -100V to generate an arc discharge between the cathode electrode and the anode electrode of the Cr-Al alloy. A hard coating layer composed of a (Cr, Al) N layer having a single phase structure having a target composition and a target layer thickness shown in Table 5 is formed on each surface of -10 and B-1 to B-6 by vapor deposition. Thus, conventional surface-coated carbide throwaway tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 as conventional coated carbide tools were produced, respectively.

Next, the coated carbide tips 1-16 of the present invention and the conventional coated carbide tip 1 in the state where each of the various coated carbide tips is screwed to the tip of the tool steel tool with a fixing jig. About ~ 16
Work material: By mass, Co-20.3% Cr-14.8% W-10. 1% Ni-1.45% Mn-0.95% Si-1.04% Fe-0.12% Co-alloy having a composition of C, four longitudinally spaced round bars equally spaced in the longitudinal direction,
Cutting speed: 60 m / min. ,
Incision: 1.5mm,
Feed: 0.15 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed cutting test of Co alloy under the conditions (cutting condition A) (normal cutting speed is 30 m / min.),
Work material: Round bar of Ti alloy having a composition of Ti-3.02% Al-2.53% V in mass%,
Cutting speed: 70 m / min. ,
Incision: 2.5mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
Dry continuous high-speed cutting test of Ti alloy under the conditions (cutting condition B) (normal cutting speed is 30 m / min.),
Work Material: Mass%, Ni-18.7% Cr-14.3% Co-4.51% Mo-2.53% Ti-1.98% Fe-1.18% Al-0.74% Four longitudinally-grooved round bars of Ni alloy having a composition of Mn-0.41% Si in the longitudinal direction,
Cutting speed: 55 m / min. ,
Cutting depth: 1mm,
Feed: 0.25 mm / rev. ,
Cutting time: 5 minutes
The dry interrupted high-speed cutting test (normal cutting speed is 30 m / min.) Of the Ni alloy under the above conditions (cutting condition C) was performed, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 6.

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 Prepare 8 .mu.m Co powder, mix these raw material powders with the composition shown in Table 7, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and then press 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 Three types of sintered carbide rod forming bodies for forming a carbide substrate having diameters of 8 mm, 13 mm, and 26 mm were formed, and further, the three types of round rod sintered bodies described above were subjected to grinding and shown in Table 7. Made of WC-base cemented carbide with a combination of 4 blade square shape with diameter and length of 6mm × 13mm, 10mm × 22mm, and 20mm × 45mm respectively, and a twist angle of 30 degrees. Carbide substrates (end mills) C-1 to C-8 were produced.

  Then, the surfaces of these carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, a lower layer composed of a (Cr, Al, B) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 8 is also shown along the layer thickness direction. A coated carbide tool of the present invention is formed by vapor-depositing an upper layer composed of alternating layers of thin layers A and B having a target composition shown in FIG. The present invention surface-coated carbide end mills (hereinafter referred to as the present invention coated carbide end mills) 1 to 8 were produced.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. And depositing a hard coating layer comprising a (Cr, Al) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 9 under the same conditions as in Example 1 above. Conventional surface-coated carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional coated carbide tools were produced, respectively.

Next, of the present invention coated carbide end mills 1-8 and conventional coated carbide end mills 1-8, the present invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3 are as follows:
Work Material-Plane: 100 mm × 250 mm, Thickness: 50 mm, and Mass%, Ni-18.7% Cr-14.3% Co-4.51% Mo-2.53% Ti-1. A plate of Ni alloy having a composition of 98% Fe-1.18% Al-0.74% Mn-0.41% Si,
Cutting speed: 45 m / min. ,
Groove depth (cut): 2 mm,
Table feed: 250 mm / min,
The dry high-speed grooving test of Ni alloy under the conditions (normal cutting speed is 25 m / min.), The coated carbide end mills 4 to 6 of the present invention and the conventional coated carbide end mills 4 to 6 are as follows:
Work Material-Plane: 100 mm × 250 mm, Thickness: 50 mm in Dimensions and Mass%, Co-20.3% Cr-14.8% W-10. 1% Ni-1.45% Mn-0. A plate material of Co alloy having a composition of 95% Si-1.04% Fe-0.12% C;
Cutting speed: 60 m / min. ,
Groove depth (cut): 3.5 mm,
Table feed: 280 mm / min,
With respect to the dry high-speed grooving test of Co alloy under the conditions (normal cutting speed is 30 m / min.), The coated carbide end mills 7 and 8 of the present invention and the conventional coated carbide end mills 7 and 8 are as follows:
Work material-plane: 100 mm x 250 mm, thickness: 50 mm, as well as mass%, Ti-3.02% Al-2.53% V Ti alloy plate,
Cutting speed: 40 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 200 mm / min,
A dry high-speed grooving test of the Ti alloy under the conditions (normal cutting speed is 20 m / min.) Is performed, and the flank wear width of the outer peripheral edge of the cutting edge is the service life in any grooving test. The cutting groove length up to 0.1 mm as a standard was measured. The measurement results are shown in Tables 8 and 9, respectively.

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

  Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating apparatus shown in FIG. 1 is also used. A lower layer composed of a (Cr, Al, B) N layer having a single phase structure with a target composition and a target layer thickness shown in Table 10 under the same conditions as in Example 1 and the same layer By vapor-depositing an upper layer composed of alternating layers of the thin layer A and the thin layer B having the target composition shown in Table 10 and a single target layer thickness along the thickness direction, with the overall target layer thickness also shown in Table 10, The surface coated carbide drills (hereinafter referred to as the present invention coated carbide drills) 1 to 8 as the present invention coated carbide tools were produced, respectively.

  For comparison purposes, the surfaces of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, and the arc shown in FIG. A hard coating layer comprising a (Cr, Al) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 11 under the same conditions as in Example 1 above, charged in the ion plating apparatus The conventional surface-coated carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional coated carbide tools were produced, respectively.

Next, of the present invention coated carbide drills 1-8 and conventional coated carbide drills 1-8, the present invention coated carbide drills 1-3 and conventional coated carbide drills 1-3 are as follows:
Work material-plane: 100 mm × 250, thickness: 50 mm, and a Ti alloy plate material having a composition of Ti-3.02% Al-2.53% V, and mass%,
Cutting speed: 40 m / min. ,
Feed: 0.15mm / rev,
Hole depth: 8mm,
With regard to the wet high-speed drilling test of Ti alloy under the conditions (normal cutting speed is 20 m / min.), The present invention coated carbide drills 4-6 and the conventional coated carbide drills 4-6,
Work Material-Plane: 100 mm × 250 mm, Thickness: 50 mm in Dimensions and Mass%, Co-20.3% Cr-14.8% W-10. 1% Ni-1.45% Mn-0. A plate material of Co alloy having a composition of 95% Si-1.04% Fe-0.12% C;
Cutting speed: 50 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 13mm,
For the Co alloy wet high-speed drilling cutting test under the conditions (normal cutting speed is 25 m / min.), The present coated carbide drills 7 and 8 and the conventional coated carbide drills 7 and 8,
Work Material-Plane: 100 mm × 250 mm, Thickness: 50 mm, and Mass%, Ni-18.7% Cr-14.3% Co-4.51% Mo-2.53% Ti-1. A plate of Ni alloy having a composition of 98% Fe-1.18% Al-0.74% Mn-0.41% Si,
Cutting speed: 60 m / min. ,
Feed: 0.1 mm / rev,
Hole depth: 28mm,
The Ni alloy wet high speed drilling cutting test (normal cutting speed is 30 m / min.) Was performed, and any wet high speed drilling cutting test (using water-soluble cutting oil) The number of drilling processes until the flank wear width reached 0.3 mm was measured. The measurement results are shown in Table 8, respectively.

  (Cr, Al, B) of the coated carbide tips 1 to 16 of the present invention, the coated carbide end mills 1 to 8 of the present invention, and the coated carbide drills 1 to 8 of the present invention. ) Upper thin layer A and thin layer B constituting the hard coating layer made of N, composition of the lower layer, conventional coated carbide tips 1 to 16 as a conventional coated carbide tool, conventional coated carbide end mill 1 to 8 and the composition of the hard coating layer made of (Cr, Al) N of the conventional coated carbide drills 1 to 8 were measured by energy dispersive X-ray analysis using a transmission electron microscope. The composition was substantially the same as the target composition.

  Further, when the average layer thickness of the constituent layers of the hard coating layer was subjected to cross-sectional measurement using a transmission electron microscope, all showed the same average value (average value of five locations) as the target layer thickness.

  From the results shown in Tables 3 to 11, each of the coated carbide tools of the present invention has an upper layer in which the hard coating layer has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm. And the thin layer A, the thin layer B, and the lower layer are composed of (Cr, Al, B) N having different compositions, and the lower layer is excellent in high-temperature hardening. In addition, the upper layer has excellent thermal conductivity and predetermined high temperature hardness and high temperature oxidation resistance, so that the hard coating layer has these excellent characteristics. Therefore, even in high-speed cutting of heat-resistant alloys such as Ni alloys, Co alloys, and Ti alloys with high heat generation, the hard coating layer exhibits an excellent heat removal effect by the upper layer, and the cutting edge portion Without the occurrence of thermoplastic deformation that causes uneven wear. The conventional coated carbide tool, in which the hard coating layer is composed of a (Cr, Al) N layer having a single-phase structure, takes the form of wear and exhibits excellent wear resistance, in particular, the thermal conductivity of the hard coating layer. Due to the shortage, the cutting edge part will undergo thermoplastic deformation, and this will cause the wear form to become an uneven wear form, so it is clear that the progress of wear will be accelerated and the service life will be reached in a relatively short time. is there.

  As described above, the coated carbide tool of the present invention is not limited to cutting under normal cutting conditions such as various steels and cast irons, particularly Ni alloys, Co alloys, and heat resistant alloys such as Ti alloys. It exhibits excellent wear resistance even in high-speed cutting with high heat generation and exhibits excellent cutting performance over a long period of time. It is possible to cope with the reduction of cost and cost.

The arc ion plating apparatus used for forming the hard coating layer which comprises this invention coated carbide 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)

On the surface of the cemented carbide substrate composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) Both are composed of an upper layer and a lower layer made of a composite nitride of Cr, Al, and B (boron), the upper layer being an average layer of 0.5 to 1.5 μm, and the lower layer being an average layer of 2 to 6 μm Each has a thickness,
(B) Each of the upper layers has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
Composition formula: [Cr _{1− (E + F)} Al _E B _F ] N (wherein, in terms of atomic ratio, E represents 0.01 to 0.06, F represents 0.20 to 0.35) and Cr A composite nitride layer of Al and B;
The thin layer B is
Composition formula: [Cr _{1− (M + N)} Al _M B _N ] N (wherein, M is 0.25 to 0.40 and N is 0.05 to 0.15 in atomic ratio) and Cr A composite nitride layer of Al and B,
(C) the lower layer has a single phase structure;
Composition formula: [Cr _{1− (X + Y)} Al _X B _Y ] N (wherein, in terms of atomic ratio, X represents 0.50 to 0.70, Y represents 0.005 to 0.05) and Cr A composite nitride layer of Al and B;
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance in high-speed cutting of heat-resistant alloys, formed by vapor-depositing a hard coating layer made of

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