JP2006001005A - Cutting tool made of surface coated cemented carbide with hard coating layer exhibiting excellent wear resistance in high speed cutting of high hardness steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated cemented carbide with a hard coating layer exhibiting excellent wear resistance in high speed cutting of high hardness steel. <P>SOLUTION: The cutting tool made of surface coated cemented carbide comprises the hard coating layer formed on the surface of a carbide substrate formed of tungsten carbide based cemented carbide or titanium carbonitride based cermet. The hard coating layer consists of: (a) a lower layer formed of a (Ti, Al, Si)N layer having an average layer thickness of 0.8-5 μm and satisfying a composition formula: (Ti<SB>1-(X+Z)</SB>Al<SB>X</SB>Si<SB>Z</SB>)N, wherein X is 0.25-0.65, and Z is 0.01-0.10 at the atomic ratio; (b) an adhesive joint layer formed of a ZrBN (zirconium boronitride) layer having an average layer thickness of 0.1-0.5 μm; and (c) an upper layer formed of a ZrB<SB>2</SB>(zirconium boride) layer having an average layer thickness of 0.8-5 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  This invention shows excellent heat dissipation with a hard coating layer, especially when cutting hard steel such as alloy tool steel and hardened material of bearing steel under high-speed cutting conditions with high heat generation. The present invention also relates to a surface-coated cemented carbide cutting tool that exhibits excellent wear resistance (hereinafter referred to as a coated cemented carbide tool).

  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.

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,
_{Formula: (Ti 1- (X + Z} ) Al X Si Z) N ( provided that an atomic ratio, X is 0.25 to 0.65, Z represents a 0.01-0.10)
Coated carbide tool formed by physical vapor deposition of a hard coating layer composed of a composite nitride of Ti, Al, and Si [hereinafter referred to as (Ti, Al, Si) N] layer satisfying the following conditions with an average layer thickness of 1 to 15 μm The (Ti, Al, Si) N layer has high-temperature hardness and heat resistance due to Al as a constituent component, high-temperature strength due to Ti, and further improved heat resistance due to Si. Together, it is also known to exhibit excellent cutting performance when used for continuous cutting and intermittent cutting of various steels and cast iron.

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—Si 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, Si) N layer.
Japanese Patent No. 2793773

  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 coated carbide tools, there is no problem when this is used to cut steel or cast iron under normal cutting conditions, but in particular Vickers hardness such as hardened materials of alloy tool steel and bearing steel. When cutting high hardness steel (C scale) with high hardness of 50 or more under high speed cutting conditions, high heat generation causes thermoplastic deformation that causes uneven wear in the hard coating layer. This is easy, and because of this, the wear progresses remarkably, so that the service life is reached in a relatively short time.

In view of the above, the present inventors have developed the above-mentioned conventional coating in order to develop a coated carbide tool that exhibits excellent wear resistance with a hard coating layer particularly in high-speed cutting such as high-hardness steel. As a result of conducting research with a focus on carbide tools,
(A) A (Ti, Al, Si) 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 0.8 to 5 μm, and boriding as an upper layer thereon When a zirconium (hereinafter referred to as ZrB ₂ ) layer is similarly formed with an average layer thickness of 0.8 to 5 μm, the ZrB ₂ layer has excellent thermal conductivity and quickly dissipates high heat generated during high-speed cutting. Therefore, it is remarkably suppressed that the hard coating layer is overheated, and the (Ti, Al, Si) N layer as the lower layer is sufficiently protected in a high heat generation environment, and as a result (Ti, The Al, Si) N layer should exhibit excellent wear resistance over a long period of time.

(B) However, the adhesion between the ZrB ₂ layer, which is the upper layer, and the (Ti, Al, Si) N layer, which is the lower layer, is not sufficient, and peeling phenomenon occurs particularly when intermittent cutting is performed at high speed. However, a zirconium boronitride (hereinafter referred to as ZrBN) layer between the ZrB ₂ layer and the (Ti, Al, Si) N layer is particularly desirable on the (Ti, Al, Si) N layer side. towards higher proportion of N components, to lower the content of the B component, whereas the ZrB is toward the _second layer side high proportion of the B component Conversely, intervening while low content of N component Then, since the ZrBN layer is firmly adhered to both the ZrB ₂ layer and the (Ti, Al, Si) N layer, the (Ti, Al, Si) N layer is superior to the surface of the carbide substrate. and I cooperation with and to have adhesion, the ZrB ₂ layer and ( i, Al, Si) The hard coating layer with the ZrBN layer interposed between the N layer and the high wear resistance of the high hardness steel with high heat generation without any delamination. To come out.

(C) The hard coating layer of (b) is, for example, an arc ion plating apparatus (hereinafter, abbreviated as AIP apparatus) having a structure shown in a schematic plan view in FIG. 1 (a) and a schematic front view in (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. Ti-Al-Si alloy was used as an electrode (evaporation source), ZrB ₂ sintered body (for example, ZrB ₂ powder as a raw material powder) was used as a cathode electrode (evaporation source) of the SP device on the other side, and formed by hot pressing. Using a vapor deposition apparatus in which a sintered body is disposed opposite to each other, a plurality of cemented carbide substrates are formed in a ring shape along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus. In this state, while rotating the rotary table with the atmosphere inside the apparatus as a nitrogen atmosphere, and rotating the carbide substrate itself for the purpose of uniforming the thickness of the hard coating layer formed by vapor deposition, basically, First, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of the Ti—Al—Si alloy, and a (Ti, Al, Si) N layer is formed as a lower layer on the surface of the cemented carbide substrate. Evaporation was performed with an average layer thickness of 8 to 5 μm, and then arc discharge between the cathode electrode (evaporation source) of the Ti—Al—Si alloy and the anode electrode was stopped, and the cathode electrode (evaporation source) of the SP apparatus was stopped. Sputtering of the ZrB ₂ sintered body arranged as) was started, and the atmosphere in the vapor deposition apparatus was changed to a mixed gas atmosphere of Ar and nitrogen instead of a nitrogen atmosphere. Increase On the other hand, the ZrBN layer was vapor-deposited with an average layer thickness of 0.1 to 0.5 μm as an adhesive bonding layer under the condition that the introduction ratio of nitrogen was gradually reduced, and then the atmosphere in the vapor deposition apparatus was finalized. In the Ar atmosphere, sputtering of the ZrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP device was continued, so that the upper layer overlapped with the ZrBN layer had an average layer thickness of 0.8 to 5 μm. It can be formed by evaporating ZrB ₂ layers.

(D) The coated carbide tool formed by vapor-depositing the hard coating layer composed of the lower layer, the adhesive bonding layer, and the upper layer has an excellent (Ti, Al, Si) N layer as the lower layer. High-temperature hardness and heat resistance, excellent high-temperature strength, and the ZrB ₂ layer firmly adhered by the ZrBN layer as the adhesive bonding layer has excellent thermal conductivity, particularly high with high heat generation Even in high-speed cutting of hardened steel, the ZrB ₂ layer significantly accelerates heat dissipation of the hard coating layer, so that the hard coating layer takes a normal wear form, and as a result, there is no occurrence of delamination in the hard coating layer, Providing excellent wear resistance over a long period of time.
The research results shown in (a) to (d) 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 0.8 to 5 μm and a composition formula: (Ti _{1− (X + Z)} Al _X Si _Z ) N (wherein, X is 0.25 to 0.65 by atomic ratio) , Z represents 0.01 to 0.10) (Ti, Al, Si) N layer composed of N layer,
(B) an adhesive bonding layer comprising a ZrBN layer having an average layer thickness of 0.1 to 0.5 μm;
(C) an upper layer consisting of _two ZrB layers having an average layer thickness of 0.8-5 μm,
It is characterized by a coated cemented carbide tool that forms a hard coating layer composed of (a) to (c) above, and exhibits excellent wear resistance especially in high-speed cutting of high-hardness steel. 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 composition formula and average layer thickness The Al component in the (Ti, Al, Si) N layer constituting the lower layer of the hard coating layer improves high temperature hardness and heat resistance, while the Ti component Although the high-temperature strength is improved and the Si component has the effect of further improving heat resistance in the coexistence with Al, the ratio of the X value indicating the proportion of Al to the total amount of Ti and B (atomic ratio, If the ratio is less than 0.25, the proportion of Ti will be excessively increased, and the high temperature hardness and heat resistance required for high speed cutting cannot be secured, and the progress of wear is accelerated rapidly. On the other hand, when the X value indicating the proportion of Al exceeds 0.65, the proportion of Ti becomes relatively small, and the high-temperature strength sharply decreases. As a result, chipping ( X value is easy to occur) Was determined to be 0.25 to 0.65.
Moreover, if the Z value indicating the proportion of Si is a proportion of the total amount of Ti and Al, and less than 0.01, the desired heat resistance improvement effect cannot be obtained, while if the Z value exceeds 0.10, Since the high-temperature strength is lowered, the Z value is set to 0.01 to 0.10.
Further, if the average layer thickness is less than 0.8 μm, it is insufficient to exhibit its excellent wear resistance over a long period of time, while if the average layer thickness exceeds 5 μm, it is the upper layer. In some cases, the average layer thickness with the ZrB ₂ layer exceeds 10 μm in total, and in this case, chipping tends to occur at the cutting edge portion, so the average layer thickness was determined to be 0.8 to 5 μm.

(B) Average layer thickness of the adhesive bonding layer If the average layer thickness is less than 0.1 μm, a strong bonding strength cannot be ensured between the upper layer and the lower layer, while the average layer thickness is 0.5 μm. If it exceeds 1, the strength of the hard coating layer suddenly decreases in the tight bonding layer portion, which causes chipping, so the average layer thickness was determined to be 0.1 to 0.5 μm.

(C) Average layer thickness of the upper layer The ZrB ₂ layer constituting the upper layer has high thermal conductivity as described above, and therefore, heat dissipation of the hard coating layer is achieved by high-speed cutting of high-hardness steel that generates particularly high heat. To prevent the (Ti, Al, Si) N layer from being thermoplastically deformed by remarkably suppressing the overheating of the (Ti, Al, Si) N layer, which is the lower layer of the hard coating layer, The effect of taking a normal wear form is exhibited. However, if the average layer thickness is less than 0.8 μm, a desired effect cannot be obtained. On the other hand, if the average layer thickness exceeds 5 μm, the lower layer The average layer thickness exceeds 10 μm in total, and in this case, chipping is likely to occur. Therefore, the average layer thickness was set to 0.8 to 5 μm.

The coated carbide tool of the present invention has a high-temperature hardness and heat resistance in which the lower layer (Ti, Al, Si) N layer constituting the hard coating layer has excellent high-temperature strength, and the same adhesive bonding layer The ZrB ₂ layer as the upper layer that is firmly and closely joined by the ZrBN layer as described above exhibits excellent heat dissipation and prevents overheating of the (Ti, Al, Si) N layer. Therefore, even in high-speed cutting of high-hardness steel, combined with the fact that the hard coating layer does not undergo thermoplastic deformation that causes uneven wear, and there is no delamination, long-term excellent wear resistance is achieved. It is demonstrated over the long term.

  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.

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. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 and ISO standard / CNMG120408. TiCN-based cemented carbide substrates B-1 to B-6 having the following chip shape were formed.
Furthermore, as a cathode electrode (evaporation source) for forming the upper layer of the hard coating layer, ZrB ₂ powder having an average particle diameter of 0.8 μm was hot pressed under the conditions of temperature: 1500 ° C., pressure: 20 MPa, holding time: 3 hours. A ZrB ₂ sintered body thus formed was prepared.

(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. Ti-Al for forming a lower layer having a predetermined composition as a cathode electrode (evaporation source) of an AIP device on one side, mounted along a peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table -Si alloy is disposed, and the upper layer and the ZrB ₂ sintered body for forming the adhesive bonding layer are disposed opposite to each other as a cathode electrode (evaporation source) of the SP device on the other side,
(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 a current of 100 A is passed between the Ti—Al—Si alloy of the cathode electrode and the anode electrode to generate an arc discharge, whereby the surface of the carbide substrate is made to the Ti—Al—Si. Bombard washed by alloy and
(C) Nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, a DC bias voltage of −100 V is applied to a carbide substrate rotating while rotating on the rotary table, and a cathode electrode A current of 100 A was passed between the Ti-Al-Si alloy and the anode electrode to generate an arc discharge, so that the surface of the cemented carbide substrate had a target composition and target layer thickness (Ti) shown in Table 3. , Al, Si) N layer is deposited as a lower layer of the hard coating layer,
(D) The arc discharge between the cathode electrode and the anode electrode of the Ti—Al—Si alloy for forming the lower layer is stopped, and the DC bias voltage (−100 V) to the cemented carbide substrate remains the same, Sputtering was started on the ZrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP apparatus under the condition of sputtering output: 3 kW, and at the same time, the atmosphere in the vapor deposition apparatus was changed to Ar and nitrogen instead of nitrogen atmosphere. However, the ZrBN layer having the target layer thickness shown in Table 3 is also used as the hard coating layer, while the Ar introduction rate is gradually increased over time while the nitrogen introduction rate is gradually reduced. Vapor-deposited as an adhesive bonding layer,
(E) While continuing the sputtering of the ZrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP device, the target layer shown in Table 3 is also used with the atmosphere in the vapor deposition device finally set to an Ar atmosphere. By forming a ZrB ₂ layer having a thickness as the upper layer of the hard coating layer, the surface-coated carbide throwaway tip (hereinafter referred to as the present invention-coated tip) 1 to 1 of the present invention coated carbide tool. 16 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, in the vapor deposition apparatus shown in FIG. Insert the Ti-Al-Si alloy with various component compositions as the cathode electrode (evaporation source), and first evacuate the inside of the device and keep it at a vacuum of 0.1 Pa or less, while using a heater. After heating the interior to 500 ° C., 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—Si alloy of the cathode electrode and the anode electrode to cause arc discharge. Thus, the surface of the carbide substrate is bombarded with the Ti—Al—Si alloy, and then nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 3 Pa, and is applied to the carbide substrate. Bahia The voltage is lowered to −100 V, and arc discharge is generated between the cathode electrode and the anode electrode of the Ti—Al—Si alloy, so that the carbide substrates A-1 to A-10 and B-1 to B— 6 by depositing a (Ti, Al, Si) N layer having a target composition and a target layer thickness shown in Table 4 on each surface as a hard coating layer. Hard throwaway tips (hereinafter referred to as conventional coated tips) 1 to 16 were produced, respectively.

Next, in the state where each of the above-mentioned various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1-16 and the conventional coated chips 1-16,
Work material: JIS · SKD61 hardened material (hardness: HRC55) round bar,
Cutting speed: 55 m / min. ,
Cutting depth: 0.15 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 2 minutes
Dry continuous high-speed cutting test of alloy tool steel under the conditions (cutting condition A) (normal cutting speed is 30 m / min.),
Work material: JIS / SUJ2 quenching material (hardness: HRC56), 4 longitudinally spaced round bars with equal intervals in the length direction,
Cutting speed: 50 m / min. ,
Cutting depth: 0.3 mm,
Feed: 0.1 mm / rev. ,
Cutting time: 2 minutes
Dry intermittent high-speed cutting test of bearing steel under the conditions (cutting condition B) (normal cutting speed is 30 m / min.),
Work material: JIS · SKD11 quenching material (hardness: HRC58) lengthwise equally spaced round bars with 4 vertical grooves,
Cutting speed: 60 m / min. ,
Cutting depth: 0.2mm,
Feed: 0.15 mm / rev. ,
Cutting time: 3 minutes
A dry intermittent high-speed cutting test (normal cutting speed is 25 m / min.) Of the alloy tool 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 5.

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 .8 μm Co powders were prepared, each of these raw material powders was blended in the composition shown in Table 6, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then shaped into a predetermined shape 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.

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. A lower layer composed of a (Ti, Al, Si) N layer having the target composition and target layer thickness shown in Table 7 and an adhesive bonding layer consisting of a ZrBN layer having the target layer thickness also shown in Table 7 And a hard coating layer composed of an upper layer composed of _two layers of ZrB by vapor deposition to form a surface coated carbide end mill (hereinafter referred to as the present coated end mill) 1 to 1 as the coated carbide tool of the present invention. 8 were produced respectively.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then loaded into the vapor deposition apparatus shown in FIG. By depositing a hard coating layer composed of a (Ti, Al, Si) N layer having the target composition and target layer thickness shown in Table 7 under the same conditions as in Example 1 above, as a conventional coated carbide tool Conventional surface-coated carbide end mills (hereinafter referred to as conventional coated end mills) 1 to 8 were produced.

Next, of the present invention coated end mills 1 to 8 and the conventional coated end mills 1 to 8, the present coated end mills 1 to 3 and the conventional coated end mills 1 to 3 are as follows:
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm thick JIS / SKD11 quenching material (hardness: HRC58),
Cutting speed: 50 m / min. ,
Groove depth (cut): 1mm,
Table feed: 260 mm / min,
The dry high-speed grooving test (normal cutting speed is 25 m / min.) Of the alloy tool steel under the conditions of the present invention, the coated end mills 4 to 6 and the conventional coated end mills 4 to 6 are as follows:
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm of JIS / SUJ2 quenching material (hardness: HRC56),
Cutting speed: 55 m / min. ,
Groove depth (cut): 2 mm,
Table feed: 180mm / min,
The dry high-speed grooving test of the bearing steel under the conditions (normal cutting speed is 30 m / min.), The coated end mills 7 and 8 of the present invention and the conventional coated end mills 7 and 8 are as follows:
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm thick JIS / SKD61 quenching material (hardness: HRC55),
Cutting speed: 60 m / min. ,
Groove depth (cut): 4 mm
Table feed: 120 mm / min,
The dry high-speed grooving test (normal cutting speed is 30 m / min.) Of the alloy tool steel under the above conditions 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, which is a guideline, was measured. The measurement results are shown in Table 7, 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 then loaded into the vapor deposition apparatus shown in FIG. Then, under the same conditions as in Example 1, the lower layer composed of the (Ti, Al, Si) N layer having the target composition and target layer thickness shown in Table 8 and the ZrBN having the target layer thickness also shown in Table 8 are used. A hard coating layer composed of an adhesive bonding layer composed of _two layers and an upper layer composed of _two ZrB layers is formed by vapor deposition to form the surface coated carbide drill of the present invention as the coated carbide tool of the present invention (hereinafter, coated with the present invention). (Referred to as drills) 1 to 8 were produced.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (drills) D-1 to D-8 are honed, ultrasonically cleaned in acetone, and dried, as shown in FIG. By charging the apparatus and vapor-depositing a hard coating layer comprising a (Ti, Al, Si) N layer having the target composition and target layer thickness shown in Table 8 under the same conditions as in Example 1 above. 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: 100 mm × 250, thickness: 50 mm thick JIS / SKD11 quenching material (hardness: HRC58),
Cutting speed: 40 m / min. ,
Feed: 0.15mm / rev,
Hole depth: 6mm,
About the wet high-speed drilling cutting test of the alloy tool steel under the conditions (normal cutting speed is 20 m / min.), The present invention coated drills 4-6 and the conventional coated drills 4-6,
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm of JIS / SUJ2 quenching material (hardness: HRC56),
Cutting speed: 50 m / min. ,
Feed: 0.12 mm / rev,
Hole depth: 12mm,
With respect to the bearing steel wet high speed drilling cutting test under the conditions (normal cutting speed is 25 m / min.), The present invention coated drills 7 and 8 and the conventional coated drills 7 and 8,
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm thick JIS / SKD61 quenching material (hardness: HRC55),
Cutting speed: 55 m / min. ,
Feed: 0.2mm / rev,
Hole depth: 30mm,
Wet high-speed drilling machining test (normal cutting speed is 30 m / min.) Of alloy tool steel under the above conditions, and the tip cutting edge surface in any wet high-speed drilling machining test (using water-soluble cutting oil) The number of drilling processes until the flank wear width was 0.3 mm was measured. The measurement results are shown in Table 8, respectively.

この結果得られた本発明被覆超硬工具としての本発明被覆チップ１〜１６、本発明被覆エンドミル１〜８、および本発明被覆ドリル１〜８の硬質被覆層を構成する（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層（下部層）の組成、並びに従来被覆超硬工具としての従来被覆チップ１〜１６、従来被覆エンドミル１〜８、および従来被覆ドリル１〜８の（Ｔｉ，Ａｌ，Ｓｉ）Ｎ層からなる硬質被覆層の組成を、透過型電子顕微鏡を用いてのエネルギー分散Ｘ線分析法により測定したところ、それぞれ目標組成と実質的に同じ組成を示した。

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 tools obtained as a result (Ti, Al, Si) ) From the composition of the N layer (lower layer) and the conventional coated chips 1-16 as a conventional coated carbide tool, the conventional coated end mills 1-8, and the (Ti, Al, Si) N layer of the conventional coated drills 1-8 When the composition of the resulting hard coating layer was measured by energy dispersive X-ray analysis using a transmission electron microscope, it showed substantially the same composition as the target composition.

  Moreover, when the average layer thickness of the constituent layers of the hard coating layer was measured by a cross-section using a scanning electron microscope, all showed an average value (average value of five locations) substantially the same as the target layer thickness.

From the results shown in Tables 3 to 8, the coated carbide tool of the present invention is the lower part of the hard coating layer even in the high-speed cutting process accompanied by the high heat generation of the hardened steel of alloy tool steel and bearing steel. The (Ti, Al, Si) N layer, which is a layer, has excellent high-temperature hardness and heat resistance, and excellent high-temperature strength, and the ZrB ₂ layer firmly adhered by the ZrBN layer as an adhesive bonding layer has excellent heat dissipation In combination with the fact that wear takes the form of normal wear and the occurrence of delamination does not occur, excellent wear resistance is demonstrated over a long period of time. In conventional coated carbide tools with a coating layer of (Ti, Al, Si) N layer, all of the hard coating layer undergoes thermoplastic deformation that causes uneven wear due to high heat generation, and the progress of wear is significantly accelerated. The ratio from It is clear that the service life is reached in a relatively short time.

  As described above, the coated carbide tool of the present invention can be used not only for cutting under normal cutting conditions such as various types of steel and cast iron, but also for high-speed cutting with high heat generation especially for high-hardness steel. Because it exhibits excellent wear resistance and excellent cutting performance over a long period of time, it is sufficient for high performance and automation of cutting equipment, labor saving and energy saving of cutting work, and further cost reduction It can respond to satisfaction.

The vapor deposition apparatus used in forming the hard coating layer which comprises a 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 0.8 to 5 μm and a composition formula: (Ti _{1− (X + Z)} Al _X Si _Z ) N (wherein, X is 0.25 to 0.65 by atomic ratio) , Z represents 0.01 to 0.10), and a lower layer made of a composite nitride layer of Ti, Al, and Si,
(B) an adhesive bonding layer comprising a zirconium boronitride layer having an average layer thickness of 0.1 to 0.5 μm;
(C) an upper layer comprising a zirconium boride layer having an average layer thickness of 0.8 to 5 μm;
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance in high-speed cutting of high-hardness steel, formed by forming a hard coating layer composed of (a) to (c) above.

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