JP2007021651A - Cutting tool made of surface coated cemented carbide having coated layer exhibiting excellent chipping resistance in high-speed 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 a coated layer exhibiting excellent chipping resistance in high-speed 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 (c) 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 lower layer formed of (Ti, Al, B)N layer having an average layer thickness ranging from 1 to 5 μm, in which Al maximum content point and minimum content point alternately exist repeatedly at predetermined intervals in the direction of layer thickness, having a component concentration distribution structure in which Al and Ti contents respectively continuously change from the Al maximum content point to the Al minimum content point and from the Al minimum content point to the Al maximum content point, and the Al maximum and minimum containing points satisfy a specific composition formula, (b) an adhesive bonding layer formed of CrN layer having an average layer thickness ranging from 0.1 to 1.5 μm, and (c) 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 occupation in the sum amount with Cr<SB>2</SB>O<SB>3</SB>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a surface-coated carbide that exhibits excellent chipping resistance even when cutting difficult-to-cut materials such as stainless steel, high manganese steel, and even mild steel under high-speed cutting conditions with high heat generation. The present invention relates to an alloy cutting tool (hereinafter referred to as a coated 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,
And having an average layer thickness of 1 to 15 μm, and along the layer thickness direction, Al highest content points and Al lowest content points are alternately present at predetermined intervals, and from the Al highest content point Al lowest content point, having a component concentration distribution structure in which the Al and Ti content continuously change from the Al lowest content point to the Al highest content point, respectively,
Furthermore, the Al highest content point, the composition _{formula: (Al 1- (X + Y} ) Ti X B Y) N ( provided that an atomic ratio, X is 0.10 to 0.35, Y is from 0.01 to 0. 1),
The Al minimum content point is the composition formula: (Al _{1− (E + F)} Ti _E B _F ) N (wherein, E is 0.40 to 0.65, F is 0.01 to 0.1) Show),
And a composite nitride layer of Al, Ti, and B (boron) having an interval between the Al highest content point and the Al minimum content point adjacent to each other of 0.01 to 0.1 μm [hereinafter referred to as (Al, Ti , B) N]], a coated carbide tool formed by physical vapor deposition of a hard coating layer is known, and (Al, Ti, B) N is a hard coating layer of the coated carbide tool. The layer has excellent high temperature hardness and heat resistance due to the Al of the component concentration distribution change structure, and excellent high temperature strength due to the Ti, and in addition to the further improvement of the high temperature hardness due to the inclusion of the B component, Excellent cutting performance when used for high-speed cutting conditions as well as continuous cutting and intermittent cutting of ordinary steel and normal cast iron under normal conditions. It is also known to do.

Further, the above conventional coated carbide tool is, for example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 2A and a schematic front view in FIG. 2B (shown as an AIP apparatus in FIG. 2). That is, a rotating table for mounting a cemented carbide substrate is provided in the center of the apparatus, and an Al—Ti—B alloy having a relatively high Al content (low Ti content) is placed on one side across the rotating table, and the other side. Using an arc ion plating apparatus in which an Al—Ti—B alloy having a relatively high Ti content (low Al content) is disposed as a cathode electrode (evaporation source) on the rotary table of the apparatus, A plurality of cemented carbide substrates are attached in a ring shape at a predetermined distance in the radial direction from the central axis, and in this state, the atmosphere in the apparatus is set as a nitrogen atmosphere and the rotary table is rotated and vapor deposition is performed. While the carbide substrate itself is rotated for the purpose of uniforming the thickness of the porous coating layer, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode on both sides, and the carbide substrate It is manufactured by forming an (Al, Ti, B) N layer on the surface, and in the (Al, Ti, B) N layer formed as a result, the ring arranged on the rotary table When the carbide substrate is closest to the cathode electrode (evaporation source) of the Al-Ti-B alloy having a relatively high Al content (low Ti content) on one side, the highest Al content in the layer And when the cemented carbide substrate is closest to the cathode electrode of the Al—Ti—B alloy having a relatively high Ti content (low Al content) on the other side, the Al minimum in the layer is formed. The content point is formed and In the layer, the highest Al content point and the lowest Al content point appear alternately at predetermined intervals along the layer thickness direction, and the lowest Al content point from the highest Al content point, from the lowest Al content point, A component concentration distribution structure in which the Al and Ti contents continuously change to the Al highest content point is formed.
JP 2004-130396 A

  In recent years, FA has been remarkable for cutting devices, but on the other hand, there are strong demands for labor saving and energy saving and further cost reduction for cutting, and as a result, coated carbide tools have an influence on the grade of work material as much as possible. However, in the conventional coated carbide tools described above, this is a low alloy steel. There is no problem when used for high-speed cutting of general steel such as steel or carbon steel, or ordinary cast iron such as ductile cast iron or gray cast iron, but stainless steel with high chip viscosity and easy welding to the tool surface. When cutting difficult-to-cut materials such as steel, high-manganese steel, and mild steel at high speed, the work material and chips made of difficult-to-cut materials are heated to a high temperature due to high heat generated during cutting. Increased further. As a result, the adhesiveness and reactivity to the surface of the hard coating layer are further increased, and as a result, the occurrence of chipping (slight chipping) at the cutting edge portion increases rapidly, which causes a service life in a relatively short time. Is the current situation.

In view of the above, the inventors of the present invention have developed the above-mentioned conventional coated carbide tool in order to develop a coated carbide tool that exhibits excellent chipping resistance with a hard coating layer particularly in high-speed cutting of difficult-to-cut materials. As a result of conducting research with a focus on hard tools,
(A) The (Al, Ti, B) N layer, which is a hard coating layer of the conventional coated carbide tool, is formed as a lower layer with an average layer thickness of 1 to 5 μm, and chromium oxide (hereinafter referred to as the 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, even in a state of being high temperature heating at high heat particularly generated during high-speed cutting Since the reactivity and affinity with the above difficult-to-cut materials are extremely low and the adhesiveness is extremely low, the (Al, Ti, B) N layer as the lower layer is sufficiently protected, and as a result ( The excellent characteristics of the (Al, Ti, B) N layer can be fully demonstrated 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 (Al, Ti, B) N layer, which is the lower layer, is not sufficient, and intermittent cutting of particularly difficult-to-cut materials is performed at high speed. In this case, a peeling phenomenon is likely to occur. However, a chromium nitride (hereinafter referred to as CrN) layer is formed between 0.1 and 1.1 between the Cr-dispersed Cr ₂ O ₃ layer and the (Al, Ti, B) N layer. When interposed with an average layer thickness of 5 μm, the CrN layer adheres firmly to both the Cr-dispersed Cr ₂ O ₃ layer and the (Al, Ti, B) N layer, so the (Al, Ti, B) Combined with the excellent adhesion of the N layer to the surface of the carbide substrate, a CrN layer is interposed between the Cr-dispersed Cr ₂ O ₃ layer and the (Al, Ti, B) N layer. The hard coating layer is excellent without causing delamination even in high-speed cutting with high heat generation of the above difficult-to-cut materials. It is like to exhibit abrasion resistance.

(D) The hard coating layer of the above (c) is, for example, an arc ion plating apparatus (hereinafter, abbreviated as AIP apparatus) having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. 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. high one relatively to the side Al content of position 90 degrees apart from each of r and Cr disperse _Cr 2 _{O 3} sintered body (low Ti content) Al-Ti-B alloy, relative to the other side In addition, a vapor deposition apparatus in which an Al—Ti—B alloy having a high Ti content (low Al content) is disposed as a cathode electrode (evaporation source) oppositely is used, and a predetermined radial direction from the central axis on the rotary table of this apparatus is used. A plurality of cemented carbide substrates are mounted in a ring shape along the outer periphery at a distance away from each other, and in this state, the rotary table is rotated with the atmosphere inside the apparatus being a nitrogen atmosphere, and the thickness of the hard coating layer formed by vapor deposition First, arc discharge is generated between the cathode electrode (evaporation source) and anode electrode of both the Al-Ti-B alloys arranged opposite to each other while the carbide substrate itself is rotated for the purpose of homogenization. Let me A (Ti, Al, B) N layer is deposited as a lower layer on the surface of the cemented carbide substrate with an average layer thickness of 1 to 5 μm, and then the cathode electrode (evaporation source) and anode of both the Al—Ti—B alloys. The arc discharge between the electrodes is stopped, and while maintaining the atmosphere in the apparatus in a nitrogen atmosphere, an arc discharge is generated between the metal Cr, which is the cathode electrode (evaporation source) of the AIP apparatus, and the anode electrode. Then, after depositing a CrN layer with an average layer thickness of 0.1 to 1.5 μm as an adhesive bonding layer, the atmosphere in the vapor deposition apparatus was set as an oxygen atmosphere and arranged as a cathode electrode (evaporation source) of the SP apparatus. It can be formed by sputtering a Cr-dispersed Cr ₂ O ₃ sintered body and depositing a Cr-dispersed Cr ₂ O ₃ layer with an average layer thickness of 1 to 5 μm as an upper layer on the CrN layer.

(E) A coated cemented carbide tool formed by vapor-depositing a hard coating layer composed of the lower layer, the tight junction layer, and the upper layer includes stainless steel, high manganese steel, and mild steel, which are particularly highly viscous and sticky. Even in high-speed cutting accompanied by high heat generation of difficult-to-cut materials such as (Al, Ti, B) N layer, the lower layer has excellent high temperature hardness and heat resistance, and excellent high temperature strength. The coexistence of the B component further improves the strength, and the Cr-dispersed Cr ₂ O ₃ layer firmly adhered by the CrN layer as the tight junction layer provides extremely low adhesion to the difficult-to-cut material and Since the reactivity is ensured, excellent wear resistance should be exhibited for a long time without delamination.
The research results shown in (a) to (e) above were obtained.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) It has an average layer thickness of 1 to 5 μm, and along the layer thickness direction, Al maximum content points and Al minimum content points are alternately present at predetermined intervals, and the Al maximum content A component concentration distribution structure in which the Al and Ti contents continuously change from the point to the Al minimum content point, from the Al minimum content point to the Al maximum content point,
Furthermore, the Al highest content point, the composition _{formula: (Al 1- (X + Y} ) Ti X B Y) N ( provided that an atomic ratio, X is 0.10 to 0.35, Y is from 0.01 to 0. 1),
The Al minimum content point is the composition formula: (Al _{1− (E + F)} Ti _E B _F ) N (wherein, E is 0.40 to 0.65, F is 0.01 to 0.1) Show),
A lower layer composed of an (Al, Ti, B) N layer, wherein the distance between the Al highest content point and the Al lowest content point adjacent to each other is 0.01 to 0.1 μm,
(B) an adhesive bonding layer comprising a CrN layer having an average layer thickness of 0.1 to 1.5 μm;
(C) It has an average layer thickness of 1 to 5 μm, and 0.1 to 5 atomic% of Cr was dispersed and distributed on 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 a chipping resistance with excellent hard coating layer in high-speed cutting of difficult-to-cut materials, formed by forming a hard coating layer composed of (a) to (c) 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) Lower layer (a) Composition of Al highest content point (Al, Ti, B) The Al component of the N layer improves the high temperature hardness and heat resistance, the Ti component improves the high temperature strength, and the same The B component has the effect of further improving the high-temperature hardness. Therefore, the Al highest content point with a relatively high Al component content has excellent high-temperature hardness and heat resistance, and high-speed cutting with high heat generation. Excellent wear resistance will be exhibited, but if the X value indicating the proportion of Ti is less than 0.10 in terms of the total amount of Al and B (atomic ratio), the proportion of Al is relatively large. Even if there is an adjacent Al minimum content point having a relatively high high-temperature strength, a decrease in the strength of the layer itself is inevitable, and as a result, chipping and the like are likely to occur, while the proportion of the Ti component is reduced. If the indicated X value exceeds 0.35, the relative In addition, the proportion of Al becomes too small, and the desired excellent high-temperature hardness and heat resistance cannot be secured, and the Y value indicating the proportion of the B component accounts for the total amount of Al and Ti (atomic ratio) ) Less than 0.01, the desired high-temperature hardness improvement effect cannot be obtained, and when the Y value exceeds 0.10, the high-temperature strength suddenly decreases. ˜0.35 and Y value of 0.01˜0.10 respectively.

(B) Composition of Al minimum content point As described above, the Al maximum content point is excellent in high-temperature hardness and heat resistance, but on the other hand, it is inferior in high-temperature strength. In order to compensate for this, the Al content is relatively high, whereby the Al minimum content points that have a relatively high high-temperature strength are alternately interposed in the thickness direction. Therefore, the Ti content (E If the value is less than 0.40 in terms of the ratio of the total amount of Al and B (atomic ratio), the desired excellent high-temperature strength cannot be secured, while the ratio (E value) is also 0.65. In the case of exceeding the ratio of Ti, the ratio of Ti becomes relatively large, and it becomes impossible to provide the predetermined desired high-temperature hardness and heat resistance at the Al minimum content point. 65, and The F value indicating the ratio of the B component was determined to be 0.01 to 0.10 for the same reason as in the above Al highest content point. .

(C) Interval between the highest Al content point and the lowest Al content point If the distance is less than 0.01 μm, it is difficult to clearly form each point with the above composition. As a result, each layer has a desired high temperature. Hardness, heat resistance, and high-temperature strength cannot be ensured, and if the distance exceeds 0.1 μm, each point has a defect, that is, if Al is the highest content point, insufficient high-temperature strength, Al minimum content point If so, high-temperature hardness and insufficient heat resistance appear locally in the layer, which makes it easier for chipping to occur on the cutting edge and promotes the progress of wear. It was defined as ˜0.1 μm.

(D) Average layer thickness If the average layer thickness is less than 1 μm, the desired wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 5 μm, chipping tends to occur on the cutting edge. The average layer thickness was determined to be 1 to 5 μm.

(B) Average layer thickness of close contact bonding layer If the average layer thickness is less than 0.1 μm, a strong bonding strength cannot be secured 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 tight junction layer portion, which causes the occurrence of chipping, so the average layer thickness was determined to be 0.1 to 1.5 μm.

(C) 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 with 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 (Al, Ti, B) N layer is protected from the high-temperature heated difficult-to-cut material and chipping occurs. However, if the average layer thickness is less than 1 μm, the desired effect cannot be obtained. On the other hand, if the average layer thickness exceeds 5 μm, the chipping tends to occur. Therefore, the average layer thickness was set to 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 in the high-speed 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 slag and the sticking phenomenon that causes the occurrence of chipping between the swarf and the chips. 5 atomic% was determined.

The coated cemented carbide tool of the present invention has a high-temperature hardness and heat resistance in which the lower layer (Al, Ti, B) N layer constituting the hard coating layer has excellent high-temperature strength, and the same adhesive bonding layer Since the Cr-dispersed Cr ₂ O ₃ layer as the upper layer firmly adhered and bonded by the CrN layer as the material ensures extremely low adhesiveness and reactivity with the work material, it is particularly viscous and adhesive. Even in high-speed cutting with high heat generation of difficult-to-cut materials such as high stainless steel, high manganese steel, and mild steel, it exhibits excellent wear resistance over a long period without chipping at the cutting edge. is there.

  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 peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table, a close contact bonding 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 oppositely as a 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. Al-Ti-B alloy for forming the highest Al content point of the lower layer as the cathode electrode (evaporation source) of the AIP device on one side at a position 90 degrees away from each, and also for forming the lowest Al content point of the lower layer on the other side Al-Ti-B alloy Direction is arranged,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, the interior of the apparatus is heated to 500 ° C. with a heater, and then rotated to a carbide substrate that rotates while rotating on the rotary table. A direct current bias voltage is applied, a current of 100 A is caused to flow between the metal Cr of the cathode electrode and the anode electrode to generate an arc discharge, and the carbide substrate surface is cleaned by Cr bombarding,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to a carbide substrate that rotates while rotating on the rotary table, An arc discharge is generated by flowing a current of 100 A between each cathode electrode (the Al-Ti-B alloy for forming the highest Al content point and the Al-Ti-B alloy for forming the lowest Al content point) and the anode electrode. Thus, on the surface of the carbide substrate, the Al highest content point and the Al lowest content point of the target composition shown in Tables 3 and 4 along the layer thickness direction alternately at the target intervals shown in Tables 3 and 4 as well. It has a component concentration distribution structure that repeatedly exists and the Al (Ti) content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and Has a target layer thickness shown in axial Table 3,4 (Al, Ti, B) N layer were vapor deposited as the lower layer of the hard coating layer,
(D) The arc discharge between the cathode electrode and the anode electrode of both the Al-Ti-B alloys for forming the lower layer is stopped, the atmosphere in the apparatus is maintained in the same nitrogen atmosphere of 4 Pa, and the carbide substrate While maintaining the same DC bias voltage (−100V) to the cathode electrode, a current of 120 A is passed between the metal Cr and the anode electrode of the cathode electrode to generate arc discharge. A CrN layer having a layer thickness is vapor-deposited as an adhesive bonding layer of a hard coating layer,
(E) Stop the arc discharge between the metal Cr and the anode electrode, make the atmosphere in the vapor deposition apparatus an Ar atmosphere of 0.5 Pa, and arrange the Cr-dispersed Cr 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 comparison purposes,
(A) Each of the above-mentioned carbide substrates A1 to A10 and B1 to B6 is ultrasonically cleaned in acetone and dried, and the outer peripheral portion is placed on the rotary table in the arc ion plating apparatus shown in FIG. As a cathode electrode (evaporation source) on one side, Al-Ti-B alloy for forming Al minimum content point having various component compositions, and various cathode electrodes (evaporation source) on the other side An Al-Ti-B alloy for forming the highest Al content point having a component composition is disposed oppositely across the rotary table, and a bombard cleaning metal Ti is also mounted.
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.5 Pa or less, the interior of the apparatus is heated to 500 ° C. with a heater, and then rotated to a carbide substrate that rotates while rotating on the rotary table. The DC bias voltage is applied, and a current of 100 A is caused to flow between the metal Ti of the cathode electrode and the anode electrode to generate an arc discharge, thereby cleaning the surface of the carbide substrate by Ti bombardment,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to a carbide substrate that rotates while rotating on the rotary table, An arc discharge is generated by flowing a current of 100 A between each cathode electrode (the Al-Ti-B alloy for forming the lowest Al content point and the Al-Ti-B alloy for forming the highest Al content point) and the anode electrode. Thus, on the surface of the cemented carbide substrate, the Al minimum content point and the Al maximum content point of the target composition shown in Tables 5 and 6 along the layer thickness direction alternately at the target intervals shown in Tables 5 and 6 as well. It has a component concentration distribution structure that repeatedly exists and the Al (Ti) content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and As shown in Tables 5 and 6, the (Al, Ti, B) N layer corresponding to the lower layer of the coated chip of the present invention having the target layer thickness is vapor-deposited as a hard coating layer. Conventional surface coated carbide throw-away 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 round bar,
Cutting speed: 350 m / min. ,
Incision: 1.5mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed cutting test of stainless steel under the conditions (cutting condition A) (normal cutting speed is 180 m / min.),
Work material: JIS / S15C lengthwise equal length 4 vertical grooved round bars,
Cutting speed: 280 m / min. ,
Incision: 1.5mm,
Feed: 0.35 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed cutting test of mild steel under the conditions (cutting condition B) (normal cutting speed is 150 m / min.),
Work material: JIS / SCMnH1 round bar,
Cutting speed: 250 m / min. ,
Cutting depth: 2mm,
Feed: 0.3 mm / rev. ,
Cutting time: 10 minutes,
The dry continuous high-speed cutting test (normal cutting speed is 150 m / min.) 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 Al minimum content point and the Al maximum content point of the target composition shown in Table 9 along the layer thickness direction alternately and repeatedly exist at the target interval shown in Table 9, and the Al maximum A target layer having a component concentration distribution structure in which the Al (Ti) content continuously changes from the content point to the Al minimum content point, from the Al minimum content point to the Al maximum content point, and also shown in Table 9 It is composed of a lower layer composed of a (Al, Ti, B) N layer having a thickness, an adhesive layer composed of a CrN layer having a target layer thickness shown in Table 9, and an upper layer composed of a Cr-dispersed Cr ₂ O ₃ layer. By evaporating and forming a hard coating layer, The present invention surface coating cemented carbide end mills of the coated cemented carbide (hereinafter, the present invention refers to the coating end mill) 1-8 were prepared, 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. In the same condition as in Example 1 above, the lowest Al content point and the highest Al content point of the target composition shown in Table 10 along the layer thickness direction are alternately at the target interval shown in Table 10 It has a component concentration distribution structure that repeatedly exists and the Al (Ti) content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and Similarly, a conventional surface coating as a conventional coated carbide tool is formed by depositing a (Al, Ti, B) N layer corresponding to the lower layer of the above-described coated end mill of the present invention having a target layer thickness shown in Table 10 as a hard coated layer. Carbide endumi (Hereinafter, conventional coating end mill called) was 1-8 were prepared, 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: 70 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 150 mm / min,
With respect to the dry high-speed grooving test of mild steel under the conditions (normal cutting speed is 40 m / min.), The coated end mills 4 to 6 and the conventional coated end mills 4 to 6 of the present invention,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 80 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 160 mm / min,
Stainless steel wet (using water-soluble cutting oil) high-speed grooving test (normal cutting speed is 40 m / min.), 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): 8 mm,
Table feed: 120 mm / min,
The high-manganese steel dry-type high-speed grooving test (normal cutting speed is 35 m / min.) Was performed under the above conditions. 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 lowest Al content point and the highest Al content point of the target composition shown in Table 11 along the layer thickness direction are repeatedly present at the target intervals shown in Table 11 alternately. And a component concentration distribution structure in which the Al (Ti) content continuously changes from the Al highest content point to the Al lowest content point, from the Al lowest content point to the Al highest content point, and 11 comprises a lower layer composed of an (Al, Ti, B) N layer having a target layer thickness shown in FIG. 11, a close contact bonding layer composed of a CrN layer having a target layer thickness also shown in Table 11, and a Cr-dispersed Cr ₂ O ₃ layer. Evaporate hard coating layer composed of upper layer By forming, the present invention surface-coated cemented carbide drills of the present invention coated cemented carbide (hereinafter, the present invention refers to the coating drills) 1-8 were prepared, 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. In an ion plating apparatus, under the same conditions as in Example 1, the Al minimum content point and the Al maximum content point of the target composition shown in Table 12 along the layer thickness direction are alternately shown in Table 12 A component concentration distribution structure in which the Al (Ti) content continuously exists from the Al highest content point to the Al lowest content point, and the Al (Ti) content continuously changes from the Al lowest content point to the Al highest content point. And (Al, Ti, B) N layer corresponding to the lower layer of the above-described coated drill of the present invention having the target layer thickness shown in Table 12 is formed by vapor deposition as a hard coating layer. Conventional surface coating as a tool Cemented carbide drills (hereinafter, conventional coating drill called) was 1-8 were prepared, 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: 150 m / min. ,
Feed: 0.15mm / rev,
Hole depth: 8mm,
For the wet high speed drilling test of stainless steel under the conditions (normal cutting speed is 80 m / min.), 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: 100 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 16mm,
For the high-manganese steel wet high speed drilling test under the conditions (normal cutting speed is 60 m / min.), 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: 50 m / min. ,
Feed: 0.25mm / rev,
Hole depth: 32mm,
Wet high-speed drilling test of mild steel under normal conditions (normal cutting speed is 30 m / min.), And any wet high-speed drilling test (using water-soluble cutting oil) is used to relieve the cutting edge surface. The number of drilling processes until the surface wear width reached 0.3 mm was measured. The measurement results are shown in Tables 11 and 12, respectively.

The hard coating layers 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 (Al, Ti, B) ) Composition of N layer (lower layer) and Cr-dispersed Cr ₂ O ₃ layer (upper layer), as well as conventional coated tips 1-16 as conventional coated carbide tools, conventional coated end mills 1-8, and conventional coated drill 1 When the composition of the hard coating layer consisting of 8 (Al, Ti, B) N layers was measured by energy dispersive X-ray analysis using a transmission electron microscope, each showed substantially the same composition as the target composition. It was.

  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 are particularly high-speed cutting accompanied by high heat generation of difficult-to-cut materials such as highly viscous and sticky stainless steel, high manganese steel, and mild steel. However, the (Al, Ti, B) N layer, which is the lower layer of the hard coating layer, has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength, and is firmly adhered by the CrN layer as an adhesive bonding layer. The Cr-dispersed Cr ₂ O ₃ layer ensures extremely low adhesion and reactivity with the work material, so that excellent wear resistance can be obtained over a long period of time without chipping at the cutting edge. In contrast, in the conventional coated carbide tools whose hard coating layer is composed only of (Al, Ti, B) N layers, all work materials (difficult to cut) are used in high-speed cutting with high heat generation. Material) and the hard coating layer Reactivity is further increased, which now chipping the cutting edge due, it is clear that lead to a relatively short time service life.

  As described above, the coated carbide tool of the present invention is not only for cutting under high-speed cutting conditions such as various general steels and ordinary cast iron, but also for high-speed machining of the above difficult-to-cut materials with high heat generation. It exhibits excellent chipping resistance even in cutting processing and exhibits excellent wear resistance over a long period of time. Therefore, it is possible to use FA for cutting equipment, further reduce labor and energy, and further reduce costs. It can respond satisfactorily.

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. The arc ion plating apparatus used for forming the hard coating layer which comprises a conventional coated carbide tool is shown, (a) is a schematic plan view, (b) is a schematic front view.

Claims (1)

On the surface of the cemented carbide substrate composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) It has an average layer thickness of 1 to 5 μm, and along the layer thickness direction, Al maximum content points and Al minimum content points are alternately present at predetermined intervals, and the Al maximum content A component concentration distribution structure in which the Al and Ti contents continuously change from the point to the Al minimum content point, from the Al minimum content point to the Al maximum content point,
Furthermore, the Al highest content point, the composition _{formula: (Al 1- (X + Y} ) Ti X B Y) N ( provided that an atomic ratio, X is 0.10 to 0.35, Y is from 0.01 to 0. 1),
The Al minimum content point is the composition formula: (Al _{1− (E + F)} Ti _E B _F ) N (wherein, E is 0.40 to 0.65, F is 0.01 to 0.1) Show),
A lower layer composed of a composite nitride layer of Al, Ti, and B (boron), in which the distance between the Al highest content point and the Al lowest content point adjacent to each other is 0.01 to 0.1 μm,
(B) an adhesive bonding layer comprising a chromium nitride layer having an average layer thickness of 0.1 to 1.5 μm;
(C) 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 composed of a chromium metal dispersed chromium oxide layer,
A surface-coated cemented carbide cutting tool that exhibits a chipping resistance with excellent hard coating layer by high-speed cutting of difficult-to-cut materials, comprising the hard coating layer composed of (a) to (c).

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