JP2008188739A - Surface coated cutting tool with excellent chipping resistance due to hard coating layer in heavy cutting of difficult-to-cut materials - Google Patents

Abstract

Provided is a surface-coated cutting tool that exhibits excellent chipping resistance in a hard coating layer in heavy cutting of difficult-to-cut materials.
The surface of the tool base has (a) an average layer thickness of 1 to 5 μm and a composition formula: (Cr _{1 -X} Y _X ) N (provided that the atomic ratio is 0.001 ≦ X ≦ 0.1) lower layer composed of a composite nitride layer of Cr and Y, (b) an intermediate layer composed of a vanadium nitride layer having an average layer thickness of 0.4 to 2 μm, (c) 0.4 to A surface-coated cutting tool formed by forming an upper layer composed of a vanadium oxide layer having an average layer thickness of 2 μm, a hard coating layer composed of the above (a) to (c).
[Selection figure] None

Description

  This invention is particularly useful when cutting difficult-to-cut materials that have high viscosity such as Al alloy, mild steel, stainless steel, etc. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent chipping resistance and lubricity with a hard coating layer.

  In general, for coated tools, throwaway inserts that are detachably attached to the tip of the cutting tool for turning and planing of various steel and cast iron materials, drilling of the work material, etc. Drills and miniature drills, and solid type end mills used for chamfering, grooving, shouldering, etc. of the work material, etc. A slow-away end mill tool that performs cutting work in the same manner as an end mill is known.

Further, as a coated tool, at least a chromium nitride (hereinafter referred to as CrN) is formed on the surface of a tool base made of tungsten carbide (hereinafter referred to as WC) based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) based cermet. It is known that coated tools formed by physical vapor deposition of a hard coating layer as a hard coating layer and that the CrN layer has excellent lubricity and wear resistance.
Further, in the CrN layer as described above, 0.01 to 10 atomic% yttrium (hereinafter referred to as Y) is contained, and a composite nitride layer of Cr and Y (hereinafter referred to as (Cr, Y) N layer). It is also known to improve its hardness by forming (shown).

Furthermore, the CrN layer of the conventional coated tool or the (Cr, Y) N layer is loaded into an arc ion plating apparatus, for example, a kind of physical vapor deposition apparatus schematically shown in FIG. In the state where the inside of the apparatus is heated to a temperature of, for example, 500 ° C. with a heater, a condition of, for example, a current of 90 A is set between the cathode electrode (evaporation source) on which Cr alloy or Cr—Y alloy is set and the anode electrode. At the same time, an arc discharge is generated and 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, vapor deposition is performed on the substrate under a condition in which a bias voltage of, for example, −100 V is applied, It is also known that the CrN layer or the (Cr, Y) N layer can be formed on the substrate surface.
JP 2006-21257 A JP 2002-337008 A Japanese Patent Laid-Open No. 2001-181824

  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 a cutting tool that can cut as many grades as possible, but in the above-mentioned conventional coated tools, this is applied to general steel such as low alloy steel and carbon steel, and ductile There is no problem when it is used for normal machining of ordinary cast iron such as cast iron and gray cast iron, but difficult to cut such as Al alloy, mild steel, stainless steel, etc., which has high chip viscosity and easily adheres to the tool surface. If cutting of the material (work material) is performed under heavy cutting conditions such as high cutting and high feed that locally apply a high load to the cutting edge, the work material and chips are generated by the heat generated during cutting. Is heated to high temperature As a result, the adhesiveness and reactivity to the surface of the hard coating layer further increase, and as a result, the occurrence of chipping (slight chipping) at the cutting edge increases rapidly. At present, the service life is reached in a relatively short time.

In view of the above, the present inventors, in particular, are hard when cutting difficult-to-cut materials such as Al alloy, mild steel, and stainless steel under heavy cutting conditions such as high cutting and high feed. As a result of conducting research on the above-mentioned conventional coated tools in order to develop a coated tool that exhibits excellent chipping resistance with a coating layer,
(A) The CrN layer, which is a hard coating layer of the conventional coated tool, contains a Y component such that the Y content in the total amount with Cr is 0.1 to 10 atomic% (Cr, Y). When the N layer is constituted, the hardness of the (Cr, Y) N layer becomes large due to the inclusion of the Y component, and the cutting tool coated with the (Cr, Y) N layer shows excellent wear resistance. On the other hand, since the (Cr, Y) N layer does not have sufficient lubricity due to the inclusion of the Y component, lubricity is difficult in heavy cutting of difficult-to-cut materials such as Al alloy, Cu alloy, mild steel, and stainless steel. Chipping is likely to occur due to lack of.

(B) However, a (Cr, Y) N layer is formed as an underlying layer with an average layer thickness of 1 to 5 μm, and an upper layer is formed thereon with vanadium oxide (vanadium oxide, depending on the degree of oxidation, VO, V ₂ O ₃ and VO ₂ can take various compound forms. However, when these layers are collectively referred to as VO), the VO layer is excellent in lubricity. Even when the material (difficult-to-cut material) and its chips are heated at high temperatures, the cutting edge (the rake and flank surfaces and the cutting edge ridge line where these two surfaces intersect) and the workpiece and the chips are always Excellent lubricity and welding resistance are ensured, and the adhesion and reactivity of the work material and chips to the cutting edge surface are remarkably reduced, and the (Cr, Y) N layer as the lower layer is sufficient. Be protected.

(C) However, when the VO layer is provided directly on the lower layer made of the (Cr, Y) N layer, the (Cr, Y) N layer as the lower layer and the VO layer as the upper layer are provided. Adhesion with the layer is not sufficient, and the high temperature strength of the VO layer itself, which is the upper layer, is not sufficient, which is due to insufficient adhesion between the lower layer and the upper layer of the hard coating layer and insufficient high temperature strength of the upper layer. Although chipping cannot be sufficiently prevented, it has a hard structure with a laminated structure in which an intermediate layer made of a VN layer is interposed between an upper layer made of the VO layer and a lower layer made of the (Cr, Y) N layer. When the covering layer is formed, the VN layer compensates for the high temperature strength that is insufficient for the VO layer, and the VN layer has excellent adhesion to both the upper layer composed of the VO layer and the lower layer composed of the (Cr, Y) N layer. Therefore, an intermediate layer consisting of a VN layer is interposed between the upper layer and the lower layer. Therefore, the bonding strength between the VO layer and the (Cr, Y) N layer is also improved. Therefore, the hard coating layer having such a laminated structure has excellent lubricity and welding resistance provided by the VO layer, and By interposing the VN layer, the bonding strength between the layers is improved. As a result, the hard coating layer exhibits excellent chipping resistance.

(D) The hard coating layer of (c) is, for example, an arc ion plating apparatus having a structure shown in a schematic plan view in FIG. 1A and a schematic front view in FIG. A tool base mounting rotary table is provided, and a metal V is disposed as a cathode electrode (evaporation source) on one side of the rotary table, and Cr-Y having a predetermined composition as a cathode electrode (evaporation source) on the other side. Using an arc ion plating apparatus in which an alloy is disposed, a plurality of tool bases are mounted in a ring shape along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus. While rotating the rotary table with the atmosphere inside the apparatus as a nitrogen atmosphere and rotating the tool base itself for the purpose of uniforming the thickness of the hard coating layer to be deposited, An arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of the above described Cr-Y alloy, and an average layer of (Cr, Y) N layer is formed on the surface of the tool base as a lower layer of 1 to 5 μm. After vapor deposition with thickness,
The arc discharge between the cathode electrode (evaporation source) of the Cr—Y alloy and the anode electrode is stopped, and subsequently the metal V as the cathode electrode (evaporation source) is maintained while maintaining the atmosphere in the apparatus in a nitrogen atmosphere. An arc discharge is generated between the anode electrode and the VN layer is deposited with an average thickness of 0.4 to 2 μm, and then the arc discharge between the metal V and the anode electrode is stopped, and at the same time in the apparatus The supply of nitrogen gas to the system is stopped, the inside of the apparatus is evacuated for about 10 seconds,
Thereafter, supply of oxygen gas into the apparatus is started to switch the atmosphere in the apparatus to an oxygen atmosphere, and arc discharge is again generated between the metal V as the cathode electrode (evaporation source) and the anode electrode, and the VN layer By depositing a VO layer with an average layer thickness of 0.4-2 μm,
A hard coating layer having a laminated structure of a (Cr, Y) N layer as a lower layer, a VN layer as an intermediate layer, and a VO layer as an upper layer can be formed by vapor deposition.

(E) The coated tool formed by vapor-depositing the hard coating layer composed of the lower layer, the intermediate layer, and the upper layer described above is particularly difficult for Al alloy, Cu alloy, mild steel, stainless steel and the like having high viscosity and adhesion. Even if the cutting work of the cutting material is performed under heavy cutting conditions such as high cutting and high feed with high load, the (Cr, Y) N layer, which is the lower layer, has excellent high-temperature hardness and the upper layer. However, the VO layer has excellent lubricity and welding resistance, and the VN layer improves the bonding strength between the lower layer and the intermediate layer. As a result, the hard coating layer having such a structure As a result, it has excellent lubricity, welding resistance, and high-temperature hardness, and heavy cutting is performed in a state where the adhesion and reactivity of difficult-to-cut materials and chips to the cutting edge surface are significantly reduced. In the cutting edge. There is no occurrence of chipping, it becomes to exhibit excellent wear resistance for a long time.
The research results shown in (a) to (e) above were obtained.

This invention was made based on the above research results,
"On the surface of the tool base made of tungsten carbide base cemented carbide or titanium carbonitride base cermet,
(A) having an average layer thickness of 1-5 μm, and
Cr and Y composite nitride satisfying the composition formula: (Cr _1-X Y _X ) N (where X is the Y content and the atomic ratio is 0.001 ≦ X ≦ 0.1) A lower layer consisting of layers,
(B) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm,
(C) an upper layer comprising a vanadium oxide layer having an average layer thickness of 0.4-2 μm,
A surface-coated cutting tool that exhibits a chipping resistance in which a hard coating layer is excellent in heavy cutting of difficult-to-cut materials, which is formed by forming the hard coating layer configured as described above in (a) to (c). "
It has the characteristics.

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

(A) Composition and average layer thickness of lower layer (Cr, Y) N constituting the lower layer has a predetermined high temperature strength and lubricity, and has an excellent high temperature hardness due to its component Y component. However, if the X value indicating the Y content is less than 0.001 in terms of the total amount with Cr (atomic ratio, the same shall apply hereinafter), the predetermined high-temperature hardness cannot be ensured. This causes a decrease in wear resistance. On the other hand, if the X value indicating the ratio of Y exceeds 0.10, the Cr content is relatively decreased, which is required for heavy cutting of difficult-to-cut materials. Not only can the high-temperature strength be secured, but also the lubricity is lowered and it is difficult to prevent chipping, so the X value is set to 0.001 to 0.10 (atomic ratio, the same applies hereinafter). It was.

  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 heavy 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.

(B) Average thickness of the intermediate layer composed of the vanadium nitride layer (VN layer) The VN layer constituting the intermediate layer of the hard coating layer itself has excellent high-temperature strength, but compensates for the lack of high-temperature strength of the VO layer. If the average layer thickness of the VN layer is less than 0.4 μm, the improvement of the high-temperature strength of the upper layer is not sufficient, whereas if the average layer thickness exceeds 2 μm, the upper part of the hard coating layer in heavy cutting of difficult-to-cut materials The lubrication characteristics (surface slipperiness) required for the layer cannot be sufficiently exhibited, and the high temperature hardness of the hard coating layer also decreases, which causes a decrease in wear resistance. The layer thickness was determined to be 0.4-2 μm.

(C) Average layer thickness of the upper layer composed of the vanadium oxide layer (VO layer) The VO layer constituting the upper layer of the hard coating layer has excellent lubricity and welding resistance, and is a work material (difficult to cut material) ) And chips are extremely low in adhesiveness and reactivity, and this is maintained without changing even when the work material is heated at high temperature during cutting. Therefore, the lower layer (Cr, Y) N layer is formed. Protects from the high-temperature heated work material and chips and exerts an action of suppressing the occurrence of chipping thereof, but if the average layer thickness is less than 0.4 μm, the desired effect cannot be obtained in the action, On the other hand, if the average layer thickness exceeds 2 μm and becomes too thick, chipping is likely to occur even if the high-temperature strength is reinforced with the laminated structure with the VN layer, so the average layer thickness is set to 0.4 to 2 μm. It was.

  In the coated tool of the present invention, the lower (Cr, Y) N layer constituting the hard coating layer has excellent high-temperature hardness, predetermined high-temperature strength and lubricity, and is laminated with a VN layer interposed. Since the upper layer formed as a structure has better lubricity (surface slipperiness), welding resistance, and high-temperature strength, the hard coating layer as a whole has excellent high-temperature hardness and high-temperature strength. As a result, it has excellent lubricity and welding resistance. As a result, heavy heat generated by difficult-to-cut materials such as highly viscous and sticky Al alloys, mild steel, stainless steel, etc. Even in cutting, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of time.

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

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended in the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C. for 1 hour, and after sintering, tool bases A-1 to A-10 made of WC-based cemented carbide with ISO standard / CNMG120408 chip shape were formed. .

In addition, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, mix these raw material powders into the composition shown in Table 2, wet mix for 24 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure Then, this green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base B made of TiCN-based cermet having an ISO standard / CNMG120408 chip shape was obtained. -1 to B-6 were formed.

(A) Next, each of the tool bases A-1 to A-10 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, and then the arc ion plating shown in FIG. Attached along the outer periphery at a predetermined distance in the radial direction from the central axis on the rotary table in the apparatus, cathode electrodes (evaporation sources) are arranged on opposite sides across the rotary table, one of which Is arranged with a metal V as a cathode electrode (evaporation source), and a Cr-Y alloy for forming a lower layer having a predetermined composition as a cathode electrode (evaporation source) on the other side.
(B) First, the inside of the apparatus is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the cathode electrode Cr-Y alloy for forming the lower layer and the anode electrode, whereby the tool base surface is made of the Cr-Y alloy. Bombard washed,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and An arc discharge is generated by passing a current of 120 A between the Cr—Y alloy of the cathode electrode and the anode electrode, and the target composition and the lower part of the target layer thickness shown in Tables 3 and 4 are formed on the surface of the tool base. After the (Cr, Y) N layer as a layer is deposited with an average layer thickness of 1 to 5 μm, the arc discharge between the cathode electrode (evaporation source) and the anode electrode of the Cr—Y alloy is stopped,
(D) Subsequently, while maintaining the atmosphere in the apparatus in a 2 Pa nitrogen atmosphere, a current of 120 A was passed between the metal V as the cathode electrode (evaporation source) and the anode electrode to generate arc discharge, and 3. After the VN layer having the target layer thickness shown in Table 4 is formed by vapor deposition, the arc discharge between the metal V and the anode electrode is stopped, and at the same time, the supply of nitrogen gas into the apparatus is stopped. Vacuum for about 10 seconds,
(E) After that, supply of oxygen gas into the apparatus is started to switch the atmosphere in the vapor deposition apparatus to an oxygen atmosphere of 0.2 Pa, and again 120 A between the metal V as the cathode electrode (evaporation source) and the anode electrode. Then, an arc discharge is generated by flowing a current of VO, and a VO layer having the target layer thickness shown in Tables 3 and 4 is formed on the VN layer by vapor deposition. Then, the arc discharge between the metal V and the anode electrode is performed. , Stop supplying oxygen gas into the device, evacuate the device for about 10 seconds,
Hard coating layers were formed by vapor deposition according to the above (a) to (e), and surface coating throwaway tips (hereinafter referred to as the present invention coated tips) 1 to 16 as the present invention coated tools were produced, respectively.

  For comparison purposes, these tool bases A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plating shown in FIG. The device was charged and a Cr—Y alloy having a predetermined composition was attached as a cathode electrode (evaporation source). First, the inside of the device was evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the device was heated to 500 ° C. with a heater. Then, a DC bias voltage of -1000 V is applied to the tool base, and an arc discharge is generated by passing a current of 100 A between the Cr-Y alloy of the cathode electrode and the anode electrode. Was bombarded with the Cr-Y alloy, nitrogen gas was introduced into the apparatus as a reaction gas to make a reaction atmosphere of 3 Pa, and a bias voltage applied to the tool base was -100 V An arc discharge is generated between the cathode electrode and the anode electrode having the predetermined composition, and the surface of each of the tool bases A-1 to A-10 and B-1 to B-6 is formed on the surface of Table 5 A surface-coated throwaway tip (hereinafter referred to as a comparative coated tip) as a comparative coating tool is formed by vapor-depositing a hard coating layer composed of a (Cr, Y) N layer having a target composition and a target layer thickness shown in Table 6. 1 to 16 were produced.

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 1-16 and the comparative coated chips 1-16,
Work material: JIS A5085 lengthwise equidistant four round grooved round bars,
Cutting speed: 790 m / min. ,
Infeed: 3.9 mm,
Feed: 1.0 mm / rev. ,
Cutting time: 10 minutes,
Of the aluminum alloy under the above conditions (cutting condition A), a dry intermittent high cutting test (normal cutting is 1.0 mm),
Work material: JIS / S11C round bar,
Cutting speed: 240 m / min. ,
Cutting depth: 3 mm,
Feed: 0.40 mm / rev. ,
Cutting time: 5 minutes,
Dry continuous high-cut cutting test of mild steel under the above conditions (cutting condition B) (normal cutting is 1.5 mm),
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 235 m / min. ,
Incision: 2 mm,
Feed: 0.45 mm / rev. ,
Cutting time: 10 minutes,
Was performed in a dry interrupted high feed cutting test (normal feed is 0.25 mm / rev.), And the flank wear width of the cutting edge was measured in any cutting test. did. The measurement results are shown in Tables 7 and 8.

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 powder was prepared, each of these raw material powders was blended in the blending composition shown in Table 9, and then added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressed 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 Then, three types of round rod sintered bodies for forming a tool base having diameters of 8 mm, 13 mm, and 26 mm were formed, and further, the three types of round rod sintered bodies were ground by grinding as shown in Table 9. In combination, the diameter x length of the cutting edge is 6 mm x 13 mm, 10 mm x 22 mm, and 20 mm x 45 mm, respectively, and each is made of a WC-based cemented carbide with a 4-flute square shape with a twist angle of 30 degrees Tool bases (end mills) C-1 to C-8 were produced.

  Subsequently, the surfaces of these tool bases (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. (Cr, Y) N layer having the target composition and target layer thickness shown in Table 10 under the same conditions as in Example 1, and a hard coating layer comprising a VN layer and a VO layer having the target layer thickness also shown in Table 10 The surface-coated carbide end mills (hereinafter referred to as the present invention-coated end mills) 1 to 16 as the present invention-coated tools were produced, respectively.

  For the purpose of comparison, the surfaces of the tool bases (end mills) C-1 to C-8 are ultrasonically cleaned in acetone and dried, and then mounted on the arc ion plating apparatus shown in FIG. Then, under the same conditions as in Example 1, a hard coating layer composed of a (Cr, Y) N layer having the target composition and target layer thickness shown in Table 11 is vapor-deposited, so that the surface coating as a conventional coating tool is performed. Carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 8 were produced.

Next, of the present invention coated end mills 1-16 and comparative coated end mills 1-8,
For the present coated end mills 1-6 and comparative coated end mills 1-3,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS A5083 plate material,
Cutting speed: 250 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 650 mm / min,
Aluminum alloy dry-type high-groove grooving test (normal groove depth is 10 mm),
For the inventive coated end mills 7-12 and comparative coated end mills 4-6,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S11C plate,
Cutting speed: 40 m / min. ,
Groove depth (cut): 10 mm,
Table feed: 130 mm / min,
Dry high-feed groove cutting test of mild steel under normal conditions (normal table feed is 100 mm / min),
About this invention coated end mills 13-16 and comparative coated end mills 7 and 8,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm
JIS / SUS304 plate material,
Cutting speed: 45 m / min. ,
Groove depth (cut): 8 mm,
Table feed: 220 mm / min,
Stainless steel dry-type high-grooving groove cutting test (normal groove depth is 3 mm),
In each groove cutting test, the cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge reached 0.1 mm, which is a guide for the service life. The measurement results are shown in Table 10 and Table 11, respectively.

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

  Next, the cutting edges of these tool bases (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. The (Cr, Y) N layer having the target composition and target layer thickness shown in Table 12 and the VN layer and VO having the target layer thickness also shown in Table 12 under the same conditions as in Example 1 above. The surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 16 as the present invention-coated tools were produced by vapor-depositing hard coating layers composed of layers.

  For the purpose of comparison, the surface of the tool base (drill) D-1 to D-8 is subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ions shown in FIG. By charging the plating apparatus and depositing a hard coating layer composed of a (Cr, Y) N layer having the target composition and target layer thickness shown in Table 13 under the same conditions as in Example 1 above, Surface coated carbide drills (hereinafter referred to as comparative coated drills) 1 to 8 as comparative coated tools were produced, respectively.

Next, of the present invention coated drills 1-16 and comparative coated drills 1-8, for the present invention coated drills 1-6 and comparative coated drills 1-3,
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS A5083 plate material,
Cutting speed: 150 m / min. ,
Feed: 0.7 mm / rev,
Hole depth: 5 mm,
Wet high feed drilling machining test of aluminum alloy under the conditions (normal feed is 0.4 mm / rev),
About this invention coated drills 7-12 and comparative coated drills 4-6,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S11C plate,
Cutting speed: 35 m / min. ,
Feed: 0.30 mm / rev,
Hole depth: 7 mm,
Wet high-feed drilling test of mild steel under normal conditions (normal feed is 0.2 mm / rev),
About this invention covering drills 13-16 and comparative covering drills 7 and 8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 100 m / min. ,
Feed: 0.35 mm / rev,
Hole depth: 10 mm,
Stainless steel wet high feed drilling cutting test under normal conditions (normal feed is 0.2 mm / rev),
In each wet high-speed drilling test (using water-soluble cutting oil), the number of drilling processes until the flank wear width of the tip cutting edge surface reached 0.3 mm was measured. The measurement results are shown in Tables 11 and 12, respectively.

  (Cr, Y) N layer (this constitutes the hard coating layer of the present coated chips 1-16, the present coated end mills 1-16, and the present coated drills 1-16 as the present coated tool obtained as a result. The composition of the lower layer) and the composition of the hard coating layer comprising the (Cr, Y) N layers of the comparative coating tips 1 to 16, the comparative coating end mills 1 to 8 and the comparative coating drills 1 to 8 as the comparative coating tool. When measured by energy dispersive X-ray analysis using a transmission electron microscope, each showed substantially the same composition as the target composition.

Furthermore, the composition of the vanadium nitride layer constituting the intermediate layer of the hard coating layer of the present coated tool and the composition of the vanadium oxide layer constituting the upper layer were also measured by energy dispersive X-ray analysis using a transmission electron microscope. The vanadium nitride layer has a structure mainly composed of VN, and the vanadium oxide layer has a mixed structure mainly composed of VO and containing V ₂ O ₃ and VO ₂ .

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

  From the results shown in Tables 7, 8, and 10-13, the coated tools of the present invention are particularly heavy, such as high cuts and high feeds of difficult-to-cut materials such as Al alloys, mild steel, and stainless steel, which are particularly highly viscous and sticky. Even in the cutting process under the cutting conditions, the (Cr, Y) N layer, which is the lower layer of the hard coating layer, has excellent high-temperature hardness and high-temperature strength in a state in which the (Cr, Y) N layer is firmly bonded to the surface of the tool base, and By the superior layer consisting of the vanadium oxide layer intervening the vanadium nitride layer as an intermediate layer, excellent lubricity between the work material and the chips and the welding resistance are ensured, without occurrence of chipping, In the comparative coated tool in which the hard coating layer is composed of a (Cr, Y) N layer and does not have a vanadium nitride layer and a vanadium oxide layer, while exhibiting excellent wear resistance over a long period of time, Said difficulty In heavy cutting of the material, the adhesiveness and reactivity between the work material (difficult to cut material) and the chips and the hard coating layer are further increased, so that chipping occurs at the cutting edge, It is clear that the service life is reached in a short time.

  As described above, the coated 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, it can fully satisfactorily cope with the FA of the cutting apparatus, labor saving and energy saving of cutting, and cost reduction.

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

Claims (1)

On the surface of the tool base composed of tungsten carbide base cemented carbide or titanium carbonitride base cermet,
(A) having an average layer thickness of 1-5 μm, and
Cr and Y composite nitride satisfying the composition formula: (Cr _1-X Y _X ) N (where X is the Y content and the atomic ratio is 0.001 ≦ X ≦ 0.1) A lower layer consisting of layers,
(B) an intermediate layer comprising a vanadium nitride layer having an average layer thickness of 0.4-2 μm,
(C) an upper layer comprising a vanadium oxide layer having an average layer thickness of 0.4-2 μm,
A surface-coated cutting tool that exhibits a chipping resistance in which a hard coating layer is excellent in heavy cutting of difficult-to-cut materials, which is formed by forming the hard coating layer configured as described above in (a) to (c).

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