JP2007021665A - Cutting tool made of surface coated cemented carbide having coated layer exhibiting excellent chipping resistance in heavy cutting work of hard-to-cut material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated cemented carbide having coated layer exhibiting excellent chipping resistance in heavy cutting work of hard-to-cut material. <P>SOLUTION: In this cutting tool made of surface coated cemented carbide, a hard coated layer formed by following (a) to (d) is formed on the surface of a tungsten carbide-base cemented carbide base body or a titanium carbide nitride-base cermet base body: (a) a base body adhesive layer formed of (Ti, Al)N layer having an average layer thickness ranging from 0.5 to 2 μm and satisfying a specific composition formula; (b) a lower layer formed of (Ti, Al, B) layer having an average layer thickness ranging from 1 to 5 μm, and satisfying a specific composition formula; (c) an interlayer adhesive layer formed of CrN layer having an average layer thickness ranging from 0.1 to 1.5 μm; and (d) an upper layer formed of Cr dispersed Cr<SB>2</SB>O<SB>3</SB>layer having an average layer thickness ranging from 1 to 5 μm, and having the structure in which metal Cr is dispersed and distributed in a base of Cr<SB>2</SB>O<SB>3</SB>by 0.1 to 5 atom% at the proportion of occupying the above Cr<SB>2</SB>O<SB>3</SB>in the sum amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  This invention exhibits excellent chipping resistance with a hard coating layer, especially when cutting difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel under heavy cutting conditions such as high cutting and high feed. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool).

  Generally, for coated carbide tools, a throw-away tip that is attached to the tip of a cutting tool for turning or flattening of various steel and cast iron work materials, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.

Further, as a coated carbide tool, on the surface of a carbide substrate composed of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet,
Ti satisfying the composition formula: (Ti _{1- (X + Y)} Al _X B _Y ) N (wherein X is 0.30 to 0.70, and Y is 0.01 to 0.10 in atomic ratio) Known is a coated carbide tool formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Al and B (boron) (hereinafter referred to as (Ti, Al, B) N) with an average layer thickness of 1 to 15 μm. And the (Ti, Al, B) N layer, which is a hard coating layer of the coated carbide tool, has high temperature hardness and heat resistance due to Al as a constituent component, high temperature strength due to the Ti, and B It is also known that when it is used for continuous cutting and intermittent cutting of various general steels and ordinary cast iron, it exhibits excellent cutting performance because it has been further improved in high-temperature hardness by the inclusion of It has been.

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, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti—Al—B alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 500 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate is applied to the surface of the carbide substrate under a condition that a bias voltage of, for example, −100 V is applied. It is also known that it is produced by vapor-depositing a hard coating layer composed of the (Ti, Al, B) N layer.
Japanese Patent No. 2793696

  In recent years, the use of FA for cutting devices has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting processing. As a result, cutting tools are affected as much as possible by the material type of the work material. There is a tendency to demand cutting tools that can cut as many grades as possible, but in the above-mentioned conventional coated carbide tools, this is applied to general steels such as low alloy steels and carbon steels. There is no problem when used for cutting of ordinary cast iron such as ductile cast iron and gray cast iron, but especially stainless steel, high manganese steel, and mild steel with high chip viscosity and easy welding to the tool surface. When cutting difficult-to-cut materials under heavy cutting conditions such as high cutting and high feed, where the load is locally applied to the cutting edge, the chips are heated to a high temperature due to the heat generated during cutting. The degree is even more As a result, not only the adhesion and reactivity to the surface of the hard coating layer are further increased, but also the adhesion of the (Ti, Al, B) N layer, which is a hard coating layer, to the substrate surface. Since it is not sufficient, in the cutting of the difficult-to-cut material under heavy cutting conditions, the occurrence of chipping (slight chipping) in the cutting edge portion increases rapidly, which leads to a service life in a relatively short time. Currently.

In view of the above, the present inventors have demonstrated excellent chipping resistance with a hard coating layer, particularly when cutting difficult-to-cut materials under heavy cutting conditions such as high cutting and high feed. As a result of conducting research focusing on the above-mentioned conventional coated carbide tools,
(A) A (Ti, Al, B) N layer, which is a hard coating layer of the above conventional coated carbide tool, is formed as a lower layer with an average layer thickness of 1 to 5 μm, and a chromium oxide (hereinafter referred to as an upper layer) is formed thereon. , the Cr ₂ O indicated by ₃₎ layer also is formed with an average layer thickness of 1 to 5 [mu] m, the Cr ₂ O ₃ layer is excellent in thermal stability, above even in a state that is specifically high temperature heating in heat generated during the cutting Since the reactivity and affinity with difficult-to-cut materials are extremely low and the adhesiveness is extremely low, the (Ti, Al, B) N layer as the lower layer is sufficiently protected, and as a result (Ti, The excellent characteristics of the Al, B) N layer can be fully exerted over a long period of time.

(B) However, since the above Cr ₂ O ₃ layer has a relatively low high-temperature strength, if it is used as it is as the upper layer of the hard coating layer, chipping occurs in the Cr ₂ O ₃ layer itself. easily, but a percentage of the total amount of the _Cr 2 _{O 3} thereto, the 0.1 to 5 atomic% of the metal chromium (Cr) and dispersed distribution and Cr disperse _Cr 2 _{O 3} layer, the Cr As a result, the high-temperature strength is improved and the occurrence of chipping is remarkably suppressed.

(C) Furthermore, the adhesion between the Cr-dispersed Cr ₂ O ₃ layer, which is the upper layer, and the (Ti, Al, B) N layer, which is the lower layer, is not sufficient, especially when intermittent cutting is performed. Chipping is likely to occur due to insufficient adhesion, but a chromium nitride (hereinafter referred to as CrN) layer of 0.1 is provided between the Cr-dispersed Cr ₂ O ₃ layer and the (Ti, Al, B) N layer. When interposed with an average layer thickness of ˜1.5 μm, the CrN layer adheres firmly to both the Cr-dispersed Cr ₂ O ₃ layer and the (Ti, Al, B) N layer. To ensure excellent adhesion.

(D) Further, as described above, the adhesion of the (Ti, Al, B) N layer to the carbide substrate surface is not sufficiently satisfactory for cutting under difficult cutting conditions under heavy cutting conditions. A composite nitride layer of Ti and Al that does not contain a B component (hereinafter referred to as (Ti, Al) N) has a composition formula: (Ti _{1 -Z} Al _Z ) N (wherein Z is 0 in terms of atomic ratio) .30 to 0.70) and with an average layer thickness of 0.5 to 2 μm, the (Ti, Al) N layer is formed on the surface of the carbide substrate and (Ti, Al, B). ) Since both N layers are firmly adhered to each other, excellent adhesion can be secured between them.

(E) The hard coating layer of (c) is an arc ion plating apparatus (hereinafter, abbreviated as AIP apparatus) having a structure shown in, for example, a schematic plan view in FIG. 1 (a) and a schematic front view in FIG. 1 (b). And a sputtering apparatus (hereinafter abbreviated as SP apparatus), that is, a carbide substrate mounting rotary table is provided at the center of the apparatus, and the cathode of the AIP apparatus is placed on one side of the rotary table. Metal Cr as an electrode (evaporation source), Cr dispersed Cr ₂ O ₃ sintered body (for example, Cr powder and Cr ₂ O ₃ powder as raw material powders) as the cathode electrode (evaporation source) of the SP device on the other side, these raw materials The powder is blended at a predetermined ratio, mixed, pressed into a green compact, and sintered body formed by sintering the powder is disposed oppositely, and further along the rotary table and the metal. Ti-Al-B alloy having a predetermined composition as a cathode electrode (vapor source) of the AIP device on one side of 90 degrees away from each of r and Cr disperse _Cr 2 _{O 3} sintered body, similarly to the other side As a cathode electrode (evaporation source) of the AIP apparatus, a vapor deposition apparatus in which a Ti—Al alloy having a predetermined composition is arranged, and the outer peripheral portion is positioned at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus. Along with this, a plurality of carbide substrates are mounted in a ring shape, and in this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the thickness of the hard coating layer formed by vapor deposition is uniform. While rotating the substrate itself, basically, first, arc discharge is generated between the cathode electrode (evaporation source) of the Ti-Al alloy and the anode electrode, and on the surface of the cemented carbide substrate, After depositing a (Ti, Al) N layer with an average layer thickness of 0.5 to 2 μm as a body adhesion layer, the arc discharge between the cathode electrode (evaporation source) and the anode electrode of the Ti—Al alloy was stopped. Subsequently, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of the Ti—Al—B alloy while keeping the atmosphere in the apparatus in a nitrogen atmosphere, and (Ti, Al , B) N layer is deposited with an average layer thickness of 1 to 5 μm, and then arc discharge between the cathode electrode (evaporation source) and anode electrode of the Ti—Al—B alloy is stopped, While maintaining the nitrogen atmosphere, an arc discharge is generated between the metal Cr, which is the cathode electrode (evaporation source) of the AIP device, and the anode electrode, and a CrN layer of 0.1 to 1.5 μm is formed as an interlayer adhesion layer. Vapor deposition with an average layer thickness of After the atmosphere in the vapor deposition apparatus with an oxygen atmosphere, overlapping the cathode electrode (vapor source) the CrN layer by performing sputtering of Cr distributed Cr ₂ O ₃ sintered body arranged as the SP device upper It can be formed by vapor-depositing a Cr-dispersed Cr ₂ O ₃ layer with an average layer thickness of 1 to 5 μm.

(F) A coated carbide tool formed by vapor-depositing a hard coating layer composed of the above-mentioned substrate adhesion layer, lower layer, interlayer adhesion layer, and upper layer is made of stainless steel or high manganese that has particularly high viscosity and adhesion. Even when cutting difficult-to-cut materials such as steel and mild steel under heavy cutting conditions such as high cutting with high load and high feed, it is firmly bonded to the surface of the carbide substrate through the substrate adhesion layer. The (Ti, Al, B) N layer, which is the lower layer, has excellent high temperature hardness and heat resistance, and excellent high temperature strength, and is superior to the upper layer due to the interposition of the CrN layer as an interlayer adhesion layer. With the action of the Cr-dispersed Cr ₂ O ₃ layer with which tight adhesion is ensured, extremely low adhesiveness and reactivity with the difficult-to-cut material are ensured, so there is no chipping at the cutting edge, Excellent wear resistance over a long period of time To become so that.
The research results shown in (a) to (f) above were obtained.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) having an average layer thickness of 0.5 to 2 μm and a composition formula: (Ti _1-Z Al _Z ) N (wherein Z represents 0.30 to 0.70 in atomic ratio) A substrate adhesion layer comprising a satisfactory (Ti, Al) N layer;
(B) having an average layer thickness of 1 to 5 μm and a composition formula: (Ti _{1− (X + Y)} Al _X B _Y ) N (wherein X is 0.30 to 0.70, Y in terms of atomic ratio) Represents a 0.01 to 0.10) (Ti, Al, B) lower layer composed of an N layer,
(C) an interlayer adhesion layer comprising a CrN layer having an average layer thickness of 0.1 to 1.5 μm;
(D) It has an average layer thickness of 1 to 5 μm, and 0.1 to 5 atomic% of Cr was dispersed and distributed in the Cr ₂ O ₃ substrate in a proportion of the total amount with the Cr ₂ O ₃ . An upper layer comprising a Cr-dispersed Cr ₂ O ₃ layer having a texture;
What is characterized by a coated carbide tool that exhibits excellent chipping resistance in heavy cutting of difficult-to-cut materials, formed by forming a hard coating layer composed of (a) to (d) above. It is.

Next, the reason why the numerical values of the constituent layers of the hard coating layer of the coated carbide tool of the present invention are limited as described above will be described.
(A) Composition of substrate adhesion layer and average layer thickness In the (Ti, Al, B) N layer as the lower layer, the B component significantly improves the high-temperature hardness of the layer itself, thereby contributing to improved wear resistance. However, the (Ti, Al) N layer constituting the substrate adhesion layer is a component that does not contain the B component. The action of Ti is to ensure strong adhesion to both the carbide substrate surface and the lower layer. On the other hand, with the same Al component, the high-temperature hardness of the layer itself and It improves the heat resistance and contributes to the improvement of the wear resistance of the hard coating layer, but the Z value indicating the proportion of Al accounts for the total amount with Ti (atomic ratio, the same shall apply hereinafter) of 0.30. If less than the specified high temperature hardness and heat resistance This is a cause of a decrease in wear resistance, and on the other hand, when the Z value indicating the Al ratio exceeds 0.70, the Ti ratio is relatively less than 0.30, The desired excellent adhesion between the surface of the carbide substrate and the lower layer cannot be ensured, so the Z value is set to 0.30 to 0.70.
Also, if the average layer thickness is less than 0.5 μm, the desired excellent adhesion cannot be secured between the surface of the cemented carbide substrate and the lower layer, while if the average layer thickness exceeds 2 μm, the above viscosity Since heavy cutting of a highly difficult-to-cut material causes a decrease in the wear resistance of the hard coating layer, the average layer thickness is set to 0.5 to 2 μm.

(B) Composition and average layer thickness of the lower layer (Ti, Al, B) The Al component in the N layer is improved in high temperature hardness and heat resistance (high temperature characteristics), and the Ti component is improved in high temperature strength. Furthermore, the B component has an effect of further improving the high temperature hardness, but when the X value indicating the proportion of Al is less than 0.30 in terms of the proportion of the total amount of Ti and B (atomic ratio, hereinafter the same), The proportion of Ti becomes excessively large and the predetermined high temperature characteristics cannot be ensured, and the progress of wear is rapidly promoted. On the other hand, the X value indicating the proportion of Al exceeds 0.70. Then, the ratio of Ti is relatively decreased, and the high temperature strength is sharply decreased. As a result, chipping or the like is likely to occur in the cutting edge portion. Therefore, the X value is set to 0.30 to 0.70. Furthermore, the Y value indicating the ratio of B is Al and Ti. If the ratio to the total amount is less than 0.01, the desired high-temperature hardness improvement effect cannot be obtained. On the other hand, if the Y value exceeds 0.10, the high-temperature strength suddenly decreases. Was determined to be 0.01 to 0.10.
Further, if the average layer thickness is less than 1 μm, it is insufficient to exhibit its excellent wear resistance over a long period of time, whereas if the average layer thickness exceeds 5 μm, the above-mentioned high viscosity is difficult. In the cutting of the cutting material, chipping is likely to occur at the cutting edge, so the average layer thickness was set to 1 to 5 μm.

(C) Average layer thickness of interlayer adhesion layer If the average layer thickness is less than 0.1 μm, it is not possible to ensure a strong bonding strength between the upper layer and the lower layer, while the average layer thickness is 1.5 μm. If it exceeds 1, the strength of the hard coating layer suddenly decreases at the interlayer adhesion layer portion, which causes the occurrence of chipping. Therefore, the average layer thickness was determined to be 0.1 to 1.5 μm.

(D) Average layer thickness of upper layer and content ratio of dispersed Cr The Cr-dispersed Cr ₂ O ₃ layer constituting the upper layer has extremely low adhesiveness and reactivity to difficult-to-cut materials as described above. Since the difficult-to-cut material is maintained without being changed even when heated at a high temperature, the lower layer (Ti, Al, B) N layer is protected from the high-temperature heated difficult-to-cut material, and chipping of this is prevented. Although the effect of suppressing is exhibited, if the average layer thickness is less than 1 μm, a desired effect cannot be obtained in the above-described operation, while if the average layer thickness exceeds 5 μm, the chipping is likely to occur. Therefore, the average layer thickness was determined to be 1 to 5 μm.
Also, the Cr in the Cr disperse Cr ₂ O ₃ layer improves the high temperature strength of the street itself above, there is a significantly effect of suppressing occurrence of chipping during the cutting with, Cr ₂ O in the percentage matrix _If the ratio to the total amount with ₃ is less than 0.1 atomic%, the desired high-temperature strength improvement effect cannot be ensured. On the other hand, if the ratio exceeds 5 atomic%, the above difficult-to-cut material that is a work material It becomes impossible to ensure extremely low tackiness and reactivity between the two and the sticking phenomenon that causes chipping between the chips and the chip appears, so that the ratio is 0.1 to 5 atoms. %.

In the coated carbide tool of the present invention, the lower layer (Ti, Al, B) N layer constituting the hard coating layer is firmly attached to the surface of the carbide substrate by the action of the (Ti, Al) N layer which is the substrate adhesion layer. Cr-dispersed Cr ₂ O ₃ layer as an upper layer having excellent high-temperature hardness and heat resistance, excellent high-temperature strength, and tightly bonded by a CrN layer as the same interlayer adhesion layer This ensures extremely low adhesion and reactivity with the work material, so that heavy and heavy loads of difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel, which are particularly viscous and sticky. Even in cutting, it exhibits excellent chipping resistance 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 in the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C for 1 hour, after sintering, WC-based carbide with honing of R: 0.03 on the cutting edge and chip shape of ISO standard CNMG120408 Alloy carbide substrates A-1 to A-10 were formed.

Further, 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 The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / TiCN-based cemented carbide substrates B-1 to B-6 having a chip shape of CNMG120408 were formed.

Furthermore, as a cathode electrode (evaporation source) for forming the upper layer of the hard coating layer, Cr ₂ O ₃ powder having an average particle diameter of 0.8 μm and Cr powder having a thickness of 1.1 μm are prepared as raw material powders. Was mixed in a predetermined composition, wet mixed in a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. The green compact was in a range of 1300 to 1400 ° C. in an Ar atmosphere of 6 Pa. A Cr-dispersed Cr ₂ O ₃ sintered body in which Cr was dispersed and contained in a predetermined ratio was prepared by sintering at a predetermined temperature for 1 hour.

(A) Next, each of the above-mentioned carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then in the vapor deposition apparatus shown in FIG. Attached along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table, an interlayer adhesion layer forming metal Cr as the cathode electrode (evaporation source) of the AIP device on one side, and the SP on the other side A Cr-dispersed Cr ₂ O ₃ sintered body for forming an upper layer is disposed opposite to the cathode electrode (evaporation source) of the apparatus, and further along the rotary table and of the metal Cr and Cr-dispersed Cr ₂ O ₃ sintered body. A Ti-Al-B alloy for forming a lower layer having a predetermined composition as a cathode electrode (evaporation source) of an AIP device on one side at a position 90 degrees away from each, and a cathode electrode (evaporation source) of the same AIP device on the other side As given The base contact layer forming Ti-Al alloy having a formation arranged,
(B) First, the interior of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, and the interior of the apparatus is heated to 700 ° C. with a heater, and then rotated to a carbide substrate that rotates while rotating on the rotary table. And applying a current of 100 A between the metal Cr and the anode electrode of the cathode electrode to generate an arc discharge, so that the surface of the carbide substrate is bombarded with the metal Cr.
(C) Introducing nitrogen gas as a reaction gas into the apparatus to form a 4 Pa reaction atmosphere, applying a DC bias voltage of −100 V to a carbide substrate rotating while rotating on the rotary table, and a cathode electrode A current of 120 A is passed between the Ti-Al alloy and the anode electrode to generate an arc discharge, so that the surface of the cemented carbide substrate has a target composition and target layer thickness (Ti) shown in Tables 3 and 4. , Al) N layer is formed by vapor deposition as a substrate adhesion layer of a hard coating layer,
(D) The arc discharge between the cathode electrode and the anode electrode of the Ti—Al alloy for forming the substrate adhesion layer is stopped, the atmosphere in the apparatus is maintained in the same nitrogen atmosphere of 4 Pa, and direct current to the carbide substrate is maintained. Similarly, with the bias voltage kept at −100 V, a current of 120 A is passed between the Ti—Al—B alloy of the cathode electrode and the anode electrode to generate an arc discharge. (Ti, Al, B) N layer having a target composition and a target layer thickness shown in 3 and 4 is deposited as a lower layer of the hard coating layer,
(E) The arc discharge between the cathode electrode and the anode electrode of the Ti-Al-B alloy for forming the lower layer is stopped, and the atmosphere in the apparatus is similarly maintained in a nitrogen atmosphere of 4 Pa. The DC bias voltage of -100V was also set to -100V, and a current of 120A was passed between the metal Cr of the cathode electrode and the anode electrode to generate an arc discharge. The CrN layer is vapor-deposited as an interlayer adhesion layer of the hard coating layer,
(F) The arc discharge between the metal Cr and the anode electrode is stopped, the atmosphere in the vapor deposition apparatus is changed to an Ar atmosphere of 0.5 Pa, and the Cr-dispersed Cr arranged as the cathode electrode (evaporation source) of the SP apparatus Sputtering is started on the ₂ O ₃ sintered body under the condition of sputtering output: 3 kW, and a Cr-dispersed Cr ₂ O ₃ layer having the target layer thickness shown in Tables 3 and 4 is formed as an upper layer of the hard coating layer. Thus, the surface-coated carbide throwaway tips (hereinafter referred to as the present invention-coated tips) 1 to 16 as the present invention coated carbide tools were produced, respectively.

  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 Ti-Al-B alloy having various component compositions as a cathode electrode (evaporation source) is inserted into a coating apparatus, and first, the inside of the apparatus is evacuated and maintained at a vacuum of 0.1 Pa or less. After heating the inside of the apparatus to 500 ° C. with a heater, a DC bias voltage of −1000 V is applied to the cemented carbide substrate, and a current of 100 A is passed between the Ti—Al—B alloy of the cathode electrode and the anode electrode. Arc discharge is generated, and the surface of the carbide substrate is bombarded with the Ti-Al-B alloy, and then nitrogen gas is introduced into the apparatus as a reaction gas to obtain a reaction atmosphere of 3 Pa. The bias voltage to be applied is lowered to -100V, and arc discharge is generated between the cathode electrode and the anode electrode of the Ti-Al-B alloy, thereby the carbide substrates A-1 to A-10 and B-1 As a conventional coated carbide tool, a (Ti, Al, B) N layer having a target composition and a target layer thickness shown in Tables 5 and 6 is vapor-deposited on each surface of B-6 as a hard coating layer. Conventional surface-coated carbide throwaway tips (hereinafter referred to as conventional coated tips) 1 to 16 were produced, respectively.

Next, in the state where each of the above various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1 to 16 and the conventional coated chips 1 to 16 are as follows.
Work material: JIS / SUS316 lengthwise equidistant 4 round grooved round bars,
Cutting speed: 300 m / min. ,
Incision: 1.5mm,
Feed: 0.6 mm / rev. ,
Cutting time: 5 minutes
(Continuous cutting is 0.4 mm / rev.)
Work material: JIS / S15C lengthwise equal length 4 vertical grooved round bars,
Cutting speed: 280 m / min. ,
Incision: 2.5mm,
Feed: 0.35 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high cut cutting test of mild steel under the above conditions (cutting condition B) (normal cutting is 1.5 mm),
Work material: JIS / SCMnH1 round bar,
Cutting speed: 250 m / min. ,
Cutting depth: 2.8 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
The dry continuous high-cutting cutting test (normal cutting is 1.5 mm) of high manganese steel under the above conditions (cutting condition C) was performed, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 7.

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 μm Co powder, mix these raw material powders with the composition shown in Table 8, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and 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 3 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 sintered rods for round bar were subjected to grinding, as 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.

Subsequently, 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 vapor deposition apparatus shown in FIG. And the lower layer composed of the (Ti, Al, B) N layer and the lower layer composed of the (Ti, Al, B) N layer with the target composition and target layer thickness shown in Table 9, The surface of the present invention as a coated carbide tool of the present invention is formed by vapor-depositing a hard coating layer composed of an interlayer adhesion layer composed of a CrN layer having the target layer thickness shown and an upper layer composed of a Cr-dispersed Cr ₂ O ₃ layer Coated carbide end mills (hereinafter referred to as the present invention coated end mills) 1 to 8 were produced, respectively.

  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. The hard coating layer consisting of the (Ti, Al, B) N layer having the target composition and target layer thickness shown in Table 10 is deposited under the same conditions as in Example 1 above. Conventional surface-coated carbide end mills (hereinafter referred to as conventional coated end mills) 1 to 8 as hard tools were produced, respectively.

Next, of the present invention coated end mills 1-8 and conventional coated end mills 1-8, the present invention coated end mills 1-3 and conventional coated end mills 1-3 are as follows:
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: 80 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 150 mm / min,
About the dry-type high cutting groove cutting test of mild steel under the conditions of (normal groove depth is 3 mm), the present invention coated end mills 4-6 and the conventional coated end mills 4-6,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 70 m / min. ,
Groove depth (cut): 7 mm,
Table feed: 130 mm / min,
For stainless steel wet (using water-soluble cutting oil) high depth groove cutting test (normal groove depth is 5 mm), coated end mills 7 and 8 of the present invention and conventional coated end mills 7 and 8
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 60 m / min. ,
Groove depth (cut): 10 mm,
Table feed: 150 mm / min,
High-manganese steel dry high-feed groove cutting test under normal conditions (normal table feed is 100 mm / min), and the flank wear width of the outer peripheral edge of the cutting edge is the service life in any groove cutting test. The cutting groove length up to 0.1 mm, which is a guideline, was measured. The measurement results are shown in Tables 9 and 10, respectively.

  The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), and from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding). Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all 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 then loaded into the vapor deposition apparatus shown in FIG. Then, under the same conditions as in Example 1, the substrate adhesion layer composed of the (Ti, Al) N layer having the target composition and the target layer thickness shown in Table 11 and the lower layer composed of the (Ti, Al, B) N layer The hard coating layer composed of an interlayer adhesion layer composed of a CrN layer having a target layer thickness shown in Table 11 and an upper layer composed of a Cr-dispersed Cr ₂ O ₃ layer is formed by vapor deposition. The surface-coated carbide drills of the present invention (hereinafter referred to as the present invention-coated drills) 1 to 8 as 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 (Ti, Al, B) N layer having the target composition and target layer thickness shown in Table 12 is formed by vapor deposition under the same conditions as in Example 1 above. Thus, conventional surface coated carbide drills (hereinafter referred to as conventional coated drills) 1 to 8 as conventional coated carbide tools were manufactured, respectively.

Next, of the present invention coated drills 1 to 8 and the conventional coated drills 1 to 8, the present invention coated drills 1 to 3 and the conventional coated drills 1 to 3 are:
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 160 m / min. ,
Feed: 0.38mm / rev,
Hole depth: 8mm,
For the stainless steel wet high feed drilling test (normal feed is 0.2 mm / rev), the present invention coated drills 4-6 and the conventional coated drills 4-6,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 120 m / min. ,
Feed: 0.4mm / rev,
Hole depth: 8mm,
For the high manganese steel wet high feed drilling test under normal conditions (normal feed is 0.25 mm / rev), the present invention coated drills 7 and 8 and the conventional coated drills 7 and 8,
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / S15C plate,
Cutting speed: m / min. ,
Feed: mm / rev,
Hole depth: mm,
Wet and high-drilling drilling test of mild steel under normal conditions (normal feed is mm / rev), and any wet high-speed drilling (with water-soluble cutting oil) flank face of the cutting edge The number of drilling processes until the wear width reached 0.3 mm was measured. The measurement results are shown in Tables 11 and 12, respectively.

(Ti, Al) N constituting the hard coating layer of the present coated chips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated carbide tool obtained as a result of this. Composition of substrate (substrate adhesion layer) and (Ti, Al, B) N layer (lower layer), further Cr-dispersed Cr ₂ O ₃ layer (upper layer), and conventional coated chips 1 to 16 as conventional coated carbide tools The composition of the hard coating layer composed of the (Ti, Al, B) N layer of the conventional coated end mills 1 to 8 and the conventional coated drills 1 to 8 was measured by energy dispersive X-ray analysis using a transmission electron microscope. As a result, each showed substantially the same composition as the target composition.

  Further, when the average layer thickness of the constituent layers of the hard coating layer was subjected to cross-sectional measurement using a scanning 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 12, all of the coated carbide tools of the present invention have high viscosities such as high cutting and high feed of difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel, which are particularly highly viscous and sticky. Even in cutting under the cutting conditions, the (Ti, Al, B) N layer, which is the lower layer of the hard coating layer, is tightly bonded to the surface of the carbide substrate by the (Ti, Al) N layer, which is the substrate adhesion layer. With the Cr-dispersed Cr ₂ O ₃ layer having excellent high-temperature hardness and heat resistance, excellent high-temperature strength, and firmly adhered to the lower layer by a CrN layer as an interlayer adhesion layer, Since extremely low adhesiveness and reactivity are ensured during this period, chipping does not occur and excellent wear resistance is exhibited over a long period of time, whereas a hard coating layer (Ti, Al, B) Conventional covering composed of N layers In the carbide tool, in the heavy cutting of the difficult-to-cut material, the adhesion and reactivity between the work material (difficult-to-cut material) and the hard coating layer are further increased, and Since the adhesion to the surface of the hard substrate is insufficient, it is clear that chipping occurs at the cutting edge and the service life is reached in a relatively short time.

  As described above, the coated carbide tool of the present invention exhibits excellent chipping resistance not only for cutting of general steel and ordinary cast iron, but particularly for heavy cutting of the above difficult-to-cut materials, and for a long time. Since it shows excellent cutting performance over time, it can sufficiently satisfactorily cope with the FA of the cutting apparatus, labor saving and energy saving of the cutting work, and further cost reduction.

The vapor deposition apparatus used in 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) having an average layer thickness of 0.5 to 2 μm and a composition formula: (Ti _1-Z Al _Z ) N (wherein Z represents 0.30 to 0.70 in atomic ratio) A substrate adhesion layer comprising a satisfactory nitride layer of Ti and Al,
(B) having an average layer thickness of 1 to 5 μm and a composition formula: (Ti _{1− (X + Y)} Al _X B _Y ) N (wherein X is 0.30 to 0.70, Y in terms of atomic ratio) Is a lower layer composed of a composite nitride layer of Ti, Al, and B (boron) satisfying 0.01 to 0.10),
(C) an interlayer adhesion layer comprising a chromium nitride layer having an average layer thickness of 0.1 to 1.5 μm,
(D) It has an average layer thickness of 1 to 5 μm, and has a structure in which 0.1 to 5 atomic% of metal chromium is dispersed and distributed in the chromium oxide base in a proportion of the total amount with the chromium oxide. An upper layer comprising a chromium-dispersed chromium oxide layer,
A surface-coated cemented carbide cutting tool that exhibits excellent chipping resistance in heavy cutting of difficult-to-cut materials, which is formed by forming a hard coating layer composed of (a) to (c) above.

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