JP2008188735A - Surface-coated cutting tool in which hard coating layer shows excellent chipping resistance in heavy cutting of difficult-to-cut material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool in which a hard coating layer shows an excellent chipping resistance in heavy cutting of a difficult-to-cut material. <P>SOLUTION: The surface-coated cutting tool is configured by forming the hard coating layer on the surface of the base body of the tool, the hard coating layer which is composed of, (a) a lower layer having a mean layer thickness of 1 to 5 μm and composed of a composite nitride layer of Cr, Al (and M) satisfying the following composition formulas: (Cr<SB>1-X</SB>Al<SB>X</SB>)N or ((Cr<SB>1-Z</SB>M<SB>Z</SB>)<SB>1-X</SB>Al<SB>X</SB>)N, where M shows one or two or more additive components selected from elements of 4a, 5a, 6a groups, Si, B, Y, in the periodic table except for Cr, and X satisfies 0.45≤X≤0.75, and Z satisfies 0.01≤Z≤0.25, (b) an intermediate layer composed of a vanadium nitride layer having a mean layer thickness of 0.4 to 2 μm, and (c) the upper layer composed of a vanadium oxide layer having a mean layer thickness of 0.4 to 2 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  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.

In addition, as a coated tool, on the surface of a tool base composed of tungsten carbide (hereinafter referred to as WC) based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) based cermet,
Composition formula: (Cr _1-P Al _P ) N or composition formula: ((Cr _1-Q M _Q ) _1-P Al _P ) N (where M is a periodic table 4a, 5a, 6a excluding Cr 1 or 2 or more kinds of additive components selected from group elements, Si, B, and Y, and P and Q indicate the content ratio of Al component and M component by atomic ratio)
Physical vapor deposition of a hard coating layer composed of a composite nitride layer of Cr and Al or a composite nitride layer of Cr, Al and M (hereinafter collectively referred to as (Cr, Al, M) N) And the (Cr, Al, M) N layer, which is a hard coating layer of the coated tool, has a high-temperature hardness due to Al as a constituent component, a high-temperature strength due to the Cr, The heat resistance is improved by the coexistence of Cr and Al. Furthermore, as the M component, one or two elements selected from the elements of groups 4a, 5a, and 6a of the periodic table excluding Cr, Si, B, and Y When containing more than seeds, the hard coating layer has improved wear resistance, high temperature oxidation resistance, and other characteristics, so it can be used for continuous cutting and intermittent cutting of various general steels and ordinary cast iron. It is also known to show excellent cutting performance when That.

Further, the above-mentioned coated tool, for example, the above-mentioned tool base is loaded into an arc ion plating apparatus which is a kind of physical vapor deposition apparatus shown schematically in FIG. Cr-Al alloy or Cr-Al-M alloy having a predetermined composition corresponding to the target composition of the hard coating layer (hereinafter collectively referred to as Cr-Al-M alloy) Is generated between the cathode electrode (evaporation source) and the anode electrode, for example, at a current of 90 A, and simultaneously nitrogen gas is introduced into the apparatus as a reaction gas, for example, a reaction atmosphere of 2 Pa, for example. On the other hand, a hard coating layer composed of a (Cr, Al, M) N layer of the target composition is applied to the surface of the tool base under the condition that a bias voltage of, for example, −100 V is applied. It is also known to be produced by vapor deposition.
JP 9-41127 A Japanese Patent Laid-Open No. 10-25566 JP 2004-106183 A JP 2004-269985 A Japanese Patent Laying-Open No. 2005-330539 JP 2006-82209 A

  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. 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 cutting of ordinary cast iron such as cast iron and gray cast iron, but especially difficult to cut stainless steel, high manganese steel, and mild steel with high chip viscosity and easy adhesion 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 viscosity increases further, and the adhesiveness and reactivity to the hard coating layer surface further increase. As a result, the occurrence of chipping (slight chipping) at the cutting edge increases rapidly, which is the cause of this. At present, the service life is reached in a relatively short time.

Therefore, the present inventors, from the above viewpoint, especially when cutting difficult-to-cut materials such as stainless steel, high manganese steel and mild steel under heavy cutting conditions such as high cutting and high feed, As a result of conducting research while focusing on the above conventional coated tools in order to develop a coated tool that exhibits excellent chipping resistance with a hard coating layer,
(A) The (Cr, Al, M) N layer, which is a hard coating layer of the above conventional coated carbide tool, is formed with an average layer thickness of 1 to 5 μm as a lower layer, and vanadium oxide (oxide) as an upper layer thereon Vanadium can take various compound forms such as VO, V ₂ O ₃ and VO ₂ depending on the degree of oxidation, but when these are collectively referred to as VO), the VO layer becomes lubricious. As a result, even when the work material (hard-to-cut material) and its chips are heated at high temperature due to the heat generated during cutting, the cutting edge (the rake face and flank face and the cutting edge ridge line where these two surfaces intersect) Excellent lubricity and welding resistance are always ensured between the work material and the chips, and the adhesion and reactivity of the work material and the chips to the cutting edge surface are remarkably reduced, and the lower layer (Cr, Al, M) N layer is well protected To become so.

(B) However, when the VO layer is provided directly on the lower layer composed of the (Cr, Al, M) N layer, the lower layer (Cr, Al, M) N layer and the upper layer are formed. Adhesion with the VO layer, which is the upper layer, is not sufficient, and the high temperature strength of the VO layer, which is the upper layer, is not sufficient, resulting in insufficient adhesion between the lower layer and the upper layer of the hard coating layer, and the high temperature strength of the upper layer It is impossible to prevent chipping due to lack.

(C) When a hard coating layer is formed 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, Al, M) N layer, The VN layer compensates for the high temperature strength that is lacking in 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, Al, M) N layer. Further, the intermediate layer composed of the VN layer is interposed between the VO layer and the (Cr, Al, M) N layer, so that the bonding strength between the VO layer and the (Cr, Al, M) N layer is improved. The VO layer has excellent lubricity and welding resistance, and the VN layer improves the bonding strength between the layers. As a result, the hard coating layer has excellent chipping resistance. To show sex

(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 on one side as a cathode electrode (evaporation source) across the rotary table, and a Cr-Al having a predetermined composition as a cathode electrode (evaporation source) on the other side. Using an arc ion plating apparatus in which an M alloy is disposed, a plurality of tool bases are attached 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, In this state, the atmosphere inside the apparatus is changed to a nitrogen atmosphere, the rotary table is rotated, and the tool base itself is rotated for the purpose of uniformizing the thickness of the hard coating layer to be deposited. First, an arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of the Cr—Al—M alloy, and a (Cr, Al, M) N layer is formed as a lower layer on the surface of the tool base. After vapor deposition with an average layer thickness of ~ 5 μm,
The metal which is the cathode electrode (evaporation source) while stopping the arc discharge between the cathode electrode (evaporation source) and the anode electrode of the Cr—Al—M alloy and subsequently maintaining the atmosphere in the apparatus in a nitrogen atmosphere An arc discharge is generated between V and the anode electrode, and a VN layer is deposited with an average layer thickness of 0.4 to 2 μm, and then the arc discharge between the metal V and the anode electrode is stopped, Stop supplying nitrogen gas into the device, evacuate the device 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, Al, M) 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 is particularly difficult to cut stainless steel, high manganese steel, and mild steel with high viscosity and adhesion. Even when the material is machined under heavy cutting conditions such as high cutting and high feed with high load, the (Cr, Al, M) N layer, which is the lower layer, has excellent high-temperature hardness, heat resistance, and high-temperature strength. Or when the layer contains an M component, the wear resistance, high-temperature oxidation resistance and the like are further improved, and the upper layer has excellent lubricity and welding resistance possessed by the VO layer. As a result, the hard coating layer having such a structure as a whole has excellent lubricity and welding resistance and excellent high temperature. Excellent properties such as strength, wear resistance and heat resistance Since the heavy-cutting process is performed with the stickiness and reactivity of the difficult-to-cut materials and chips to the cutting edge surface being significantly reduced, chipping at the cutting edge is eliminated. , To exhibit excellent wear resistance over a long period of time.
The research results shown in (a) to (e) above were obtained.

This invention was made based on the above research results,
“(1) On the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
(A) having an average layer thickness of 1-5 μm, and
Composite nitride of Cr and Al satisfying the composition formula: (Cr _1-X Al _X ) N (where X represents the Al content ratio, and the atomic ratio is 0.45 ≦ X ≦ 0.75) 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).
(2) On the surface of the tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
(A) having an average layer thickness of 1-5 μm, and
_Formula: with _{((Cr 1-Z M Z} ) 1-X Al X) N ( wherein, M is chosen Periodic Table 4a except Cr, 5a, elements of Group 6a, Si, B, from among Y 1 or 2 or more added components, X represents the Al content, Z represents the M content, and the atomic ratio is 0.45 ≦ X ≦ 0.75, 0.01 ≦ Z ≦ 0.25) and a lower layer composed of a composite nitride layer of Cr, Al, and M,
(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).
(3) The additive component M is one or more selected from Si, B, and Y, and the hard coating layer is formed by heavy cutting of a difficult-to-cut material according to claim 2. A surface-coated cutting tool with excellent chipping resistance. "
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) Lower layer composition and average layer thickness The Al component, which is a component of (Cr, Al, M) N constituting the lower layer, improves the high-temperature hardness of the hard coating layer, and the Cr component has a high temperature. It has the effect of improving strength and improving heat resistance by coexistence of Cr and Al. Further, among the M components, elements of the periodic table 4a, 5a, 6a group excluding Cr, Si, B, Has the effect of improving the wear resistance of the hard coating layer, and Y has the effect of improving the high temperature oxidation resistance of the hard coating layer, but the X value indicating the proportion of Al is the total amount of Cr Alternatively, if the ratio of the total amount of Cr and M (atomic ratio, hereinafter the same) is less than 0.45, the predetermined high-temperature hardness cannot be secured, which causes a decrease in wear resistance, while Al When the X value indicating the ratio exceeds 0.75, the Cr content is relatively low. The proportion is reduced, the high-temperature strength required for heavy cutting of difficult-to-cut materials cannot be secured, it becomes difficult to prevent chipping, and the content of M component Z If the value is less than 0.01 in terms of the total amount with Cr (atomic ratio, the same applies hereinafter), improvement in properties such as wear resistance and high-temperature oxidation resistance due to inclusion of the M component cannot be expected. When the Z value exceeds 0.25, a decreasing tendency appears in the high-temperature strength. Therefore, the X value is set to 0.45 to 0.75, and the Z value is set to 0.01 to 0.25.

  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 adhesion and reactivity, and this is maintained without changing even when the work material is heated at high temperature during cutting, so that it is the lower layer (Cr, Al, M) N The layer is protected from the high-temperature heated work material and chips, and exhibits an effect of suppressing the occurrence of chipping. However, when the average layer thickness is less than 0.4 μm, a desired effect can be obtained in the function. 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 by the laminated structure with the VN layer, so the average layer thickness is 0.4-2 μm. It was determined.

  In the coated tool of the present invention, the lower layer (Cr, Al, M) N layer constituting the hard coating layer has excellent high temperature hardness, heat resistance, high temperature strength, or even better wear resistance. It has high temperature oxidation resistance, and the upper layer formed as a laminated structure with a VN layer intervening has excellent lubricity (surface slipperiness), welding resistance, and high temperature strength. The coating layer as a whole has excellent high-temperature hardness, heat resistance, high-temperature strength, etc., as well as excellent lubricity and welding resistance. Steels and even hard-to-cut materials such as mild steel are accompanied by large heat generation, and exhibit excellent chipping resistance and excellent wear resistance over a long period even in heavy cutting with heavy loads. It is.

  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, the 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 The metal V is disposed as a cathode electrode (evaporation source), and a Cr—Al-M alloy for forming a lower layer having a predetermined composition is disposed as the 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 a current of 100 A is passed between the cathode electrode Cr-Al-M alloy for forming the lower layer and the anode electrode to generate an arc discharge. -Bombarded with M alloy,
(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—Al—M alloy of the cathode electrode and the anode electrode, and the target composition and target layer thickness shown in Tables 3 and 4 are formed on the surface of the tool base. (Cr, Al, M) N layer as a lower layer is deposited with an average layer thickness of 1 to 5 μm, and then an arc between the cathode electrode (evaporation source) and anode electrode of the Cr—Al—M alloy is formed. Stop discharging,
(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,
The hard coating layer was formed by vapor deposition according to the above (a) to (e), and the present surface coated throwaway tips (hereinafter referred to as the present coated tips) 1 to 39 as the coated tools of the present invention were produced.

  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-Al-M alloy having a predetermined composition was mounted as a cathode electrode (evaporation source). After heating to 500 ° C., a DC bias voltage of −1000 V is applied to the tool base, and a current of 100 A is passed between the cathode electrode Cr—Al—M alloy and the anode electrode to generate arc discharge, Thus, the surface of the tool base is bombarded with the Cr—Al—M alloy, then nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 3 Pa, and a via applied to the tool base. The voltage is lowered to -100 V to generate an arc discharge between each cathode electrode and anode electrode having the predetermined composition, whereby each of the tool bases A-1 to A-10 and B-1 to B-6 is generated. A surface coating throwaway as a comparative coating tool is formed by vapor-depositing a hard coating layer composed of (Cr, Al, M) N layers having the target composition and target layer thickness shown in Tables 5 and 6 on the surface. Chips (hereinafter referred to as comparative coated chips) 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 to 39 and the comparative coated chips 1 to 16 are as follows.
Work material: JIS · SCMnH1 lengthwise equidistant four round grooved round bars,
Cutting speed: 220 m / min. ,
Cutting depth: 3 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 minutes,
Of high manganese steel under the above conditions (cutting condition A), a dry intermittent high cutting test (normal cutting is 1.5 mm),
Work material: JIS / SUS304 round bar,
Cutting speed: 230 m / min. ,
Incision: 2 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high-cut cutting test under normal conditions (cutting condition B) (normal cutting is 1.5 mm),
Work material: JIS-S11C lengthwise equal 4 round grooved round bars,
Cutting speed: 230 m / min. ,
Cutting depth: 3 mm,
Feed: 0.5 mm / rev. ,
Cutting time: 5 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. . The measurement results are shown in Tables 7 and 8.

As in Example 1, all of WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder having an average particle diameter of 1 to 3 μm. The raw material powder is blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. , Temperature: Sintered at 1400 ° C. for 1 hour to form a round tool sintered body for forming a tool base having a diameter of 13 mm. WC-base cemented carbide tool bases (end mills) A-1 to A-10 having a four-blade square shape with a diameter x length of 10 mm x 22 mm and a twist angle of 30 degrees were manufactured, respectively. .

  Then, the surfaces of these tool bases (end mills) A-1 to A-10 were ultrasonically cleaned in acetone and dried, and then inserted into the arc ion plating apparatus shown in FIG. Under the same conditions as in Example 1, a (Cr, Al, M) N layer having a target composition and a target layer thickness shown in Table 10, and a hard layer composed of a VN layer and a VO layer having a target layer thickness also shown in Table 9 The surface-coated carbide end mills (hereinafter referred to as the present invention-coated end mills) 1 to 27 as the present invention-coated tools were produced by depositing the coating layer, respectively.

  For the purpose of comparison, the surfaces of the tool bases (end mills) A-1 to A-10 are ultrasonically cleaned in acetone and dried, and then mounted on the arc ion plating apparatus shown in FIG. And by depositing a hard coating layer composed of (Cr, Al, M) N layers having the target composition and target layer thickness shown in Table 10 under the same conditions as in Example 1 above, Surface-coated carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 10 were produced.

Next, with respect to the present invention coated end mills 1 to 27 and comparative coated end mills 1 to 10,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 50 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 250 mm / min,
High-manganese steel dry-type high-grooving groove cutting test under normal conditions (cutting condition D) (normal groove depth is 3 mm),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 60 m / min. ,
Groove depth (cut): 3.5 mm,
Table feed: 240 mm / min,
Stainless steel dry high feed groove cutting test under normal conditions (cutting condition E) (normal table feed is 120 mm / min),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S11C plate,
Cutting speed: 40 m / min. ,
Groove depth (cut): 7 mm,
Table feed: 150 mm / min,
Dry high-cut groove cutting test of mild steel under normal conditions (cutting condition F) (normal groove depth is 5 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 9 and Table 10, respectively.

  Using the round bar sintered body with a diameter of 13 mm manufactured in Example 2 above, from this round bar sintered body, the diameter x length of the groove forming portion is 8 mm x 22 mm, respectively, by grinding, and WC-base cemented carbide tool bases (drills) A-1 to A-10 having a two-blade shape with a twist angle of 30 degrees were manufactured.

  Next, the cutting edges of these tool bases (drills) A-1 to A-10 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. The (Cr, Al, M) N layer having the target composition and target layer thickness shown in Table 11 and the VN layer having the target layer thickness also shown in Table 11 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 27 as the present invention-coated tools were produced by vapor-depositing and forming a hard coating layer comprising VO and VO layers.

  For the purpose of comparison, the surfaces of the above-mentioned tool bases (drills) A-1 to A-10 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ions shown in FIG. A hard coating layer composed of a (Cr, Al, M) N layer having the target composition and target layer thickness shown in Table 12 is formed by vapor deposition under the same conditions as in Example 1 above. Thus, surface coated carbide drills (hereinafter referred to as comparative coated drills) 1 to 10 as comparative coated tools were manufactured, respectively.

Next, about the said invention coated drill 1-27 and the comparative coated drill 1-10,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH1 plate material,
Cutting speed: 70 m / min. ,
Feed: 0.4 mm / rev,
Hole depth: 10 mm,
Wet high feed drilling test of high manganese steel under the above conditions (cutting condition G) (normal feed is 0.2 mm / rev),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 100 m / min. ,
Feed: 0.4 mm / rev,
Hole depth: 10 mm,
Stainless steel wet high feed drilling test under normal conditions (cutting condition H) (normal feed is 0.2 mm / rev),
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S11C plate,
Cutting speed: 45 m / min. ,
Feed: 0.3 mm / rev,
Hole depth: 7 mm,
Wet high feed drilling test of mild steel under normal conditions (cutting condition I) (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, Al, M) N constituting the hard coating layers of the present coated tips 1 to 39, the present coated end mills 1 to 27, and the present coated drills 1 to 27 as the present coated tools obtained as a result. The composition of the layer (lower layer), and the hard coating comprising the (Cr, Al, M) N layer of the comparative coating tip 1-16 as the comparative coating tool, the comparative coating end mill 1-10, and the comparative coating drill 1-10 The composition of the layers was measured by energy dispersive X-ray analysis using a transmission electron microscope, and 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 to 12, all of the coated tools of the present invention are particularly heavy cutting conditions such as high cutting and high feed of difficult-to-cut materials such as stainless steel and high manganese steel having high viscosity and adhesion, and mild steel. Even in the cutting process, the (Cr, Al, M) N layer, which is the lower layer of the hard coating layer, is in a tightly bonded state to the surface of the tool base, and has excellent high temperature hardness, heat resistance, high temperature strength, or In addition to this, the upper layer composed of a vanadium oxide layer having excellent wear resistance and high-temperature oxidation resistance and interposing a vanadium nitride layer as an intermediate layer provides a gap between the work material and the chips. Excellent lubricity and welding resistance are ensured, so that chipping does not occur and excellent wear resistance is exhibited over a long period of time, while the hard coating layer is (Cr, Al, M) N It is composed of layers and nitrided In the comparative coated tool which does not have a rhodium layer and a vanadium oxide layer, in both heavy cutting of the difficult-to-cut material, the adhesiveness and reactivity of the work material (hard-to-cut material) and chips and the hard coating layer are low. Since it becomes higher, it becomes clear that chipping occurs at the cutting edge and the service life is reached in a relatively 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 (3)

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
Composite nitride of Cr and Al satisfying the composition formula: (Cr _1-X Al _X ) N (where X represents the Al content ratio, and the atomic ratio is 0.45 ≦ X ≦ 0.75) 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). 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
_Formula: with _{((Cr 1-Z M Z} ) 1-X Al X) N ( wherein, M is chosen Periodic Table 4a except Cr, 5a, elements of Group 6a, Si, B, from among Y 1 or 2 or more added components, X represents the Al content, Z represents the M content, and the atomic ratio is 0.45 ≦ X ≦ 0.75, 0.01 ≦ Z ≦ 0.25) and a lower layer composed of a composite nitride layer of Cr, Al, and M,
(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).   The additive component M is one or more selected from Si, B, and Y, wherein the hard coating layer has excellent resistance to hard cutting in heavy cutting of difficult-to-cut materials. Surface coated cutting tool that demonstrates chipping properties.

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