JP5088480B2 - Surface coated cutting tool - Google Patents

Description

  This invention cuts work material with high weldability, such as mild steel and stainless steel, with high heat generation and high-speed heavy cutting such as high feed and high cutting with high load acting on the cutting edge. The present invention also relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent chipping resistance and wear resistance even when performed under conditions.

  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 and shouldering 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.

Conventionally, as one of the coated tools, for example, a substrate (hereinafter referred to as a tool substrate) composed of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. On the surface,
(A) Composition formula: (Al _1-X Ti _X ) N (however, in atomic ratio, 0.3 ≦ X ≦ 0.7),
A lower layer composed of a composite nitride of Al and Ti [hereinafter referred to as (Al, Ti) N] layer satisfying
(B) Composition formula: (Al1- [ _alpha] Cr [ _alpha] ) N or (Al1- [ _{beta]-[gamma]} Cr [ _beta] M [ _gamma] ) N (where M is an element of groups 4a, 5a, and 6a of the periodic table excluding Cr) , Si, B, Y are one or more additive components selected from the group consisting of 0.2 ≦ α ≦ 0.6, 0.10 ≦ β ≦ 0.54,. Al / Cr composite nitride [hereinafter referred to as (Al, Cr) N] layer or Al / Cr / M composite nitridation satisfying 01 ≦ γ ≦ 0.25 and 0.2 ≦ β + γ ≦ 0.6) An upper layer composed of layers [hereinafter referred to as (Al, Cr, M) N],
A coated tool in which a hard coating layer comprising the above (a) and (b) is formed by vapor deposition is known, and when this is used for continuous cutting and intermittent cutting processing of various steels and cast irons, it has excellent resistance. It is also known to exhibit deficiency.

Further, the above-mentioned coated tool is loaded with the above-mentioned tool base in an arc ion plating apparatus which is one type of physical vapor deposition apparatus shown schematically in FIG. 1, for example, and the inside of the apparatus is heated at, for example, 500 ° C. An arc discharge is generated between the anode electrode and the cathode electrode (evaporation source) on which an Al—Ti alloy having a predetermined composition is set, for example, at a current of 90 A, and at the same time in the apparatus. Nitrogen gas is introduced as a reaction gas to obtain a reaction atmosphere of, for example, 2 Pa. On the other hand, the above-described (Al, Ti) N is applied to the surface of the tool base under the condition that a bias voltage of, for example, −100 V is applied to the tool base. After forming the layer as a lower layer, an arc discharge is generated between the cathode electrode (evaporation source) on which the Al—Cr alloy or Al—Cr—M alloy is set and the anode electrode. On the surface of the lower layer, is also known to be produced by depositing form (Al, Cr) N layer or (Al, Cr, M) N layer as the upper layer.
JP 2005-262388 A JP 2005-305576 A

  In recent years, the use of FA for cutting devices has been remarkable. On the other hand, there has been a strong demand for labor saving and energy saving and further cost reduction for cutting processing, and along with this, cutting processing tends to be further accelerated. For coated tools, there is no problem when this is used for cutting under normal cutting conditions such as various steels and cast irons. In particular, work materials with high weldability such as mild steel and stainless steel. However, when it is used for high-speed heavy cutting with high heat generation and high load acting on the cutting edge, the hard coating layer has insufficient heat conductivity and heat dissipation. The layer is overheated by the high heat generated during cutting, and a considerable temperature rise is unavoidable. As a result, the hard coating layer undergoes thermoplastic deformation or uneven wear, which promotes the progress of wear. Service life in a short time The leads to is the status quo.

  In view of the above, the present inventors, in particular, cut a work material with high weldability, such as mild steel and stainless steel, with high heat generation and a high load acting on the cutting edge. In order to develop a coated tool that exhibits excellent fracture resistance and wear resistance even when performed under high-speed heavy cutting conditions such as high feed and high depth of cut, we focus on the above-mentioned conventional coated tools for research. As a result, the following knowledge was obtained.

(A) In the above conventional coated tool in which the lower layer of the hard coating layer is an (Al, Ti) N layer and the upper layer is an (Al, Cr) N layer or (Al, Cr, M) N layer The (Al, Cr) N layer or the (Al, Cr, M) N layer is used as an intermediate layer, and further, as an upper layer, from the intermediate layer side toward the upper layer surface (along the layer thickness direction) When the (Al, Cr) N layer or (Al, Cr, M) N layer having a composition gradient type concentration distribution structure in which the content ratio of N as a constituent component of the layer is reduced is formed, the composition gradient type is formed. In particular, the upper layer has excellent thermal conductivity, heat dissipation, and lubricity, so even if the hard coating layer is heated to a high temperature during high-speed heavy cutting, the heat is immediately dissipated and the hard coating layer is overheated. In addition, against the surface of the cutting edge of the work material and chips The welding is also significantly reduced.
In addition, said M shows the 1 type, or 2 or more types of additional component chosen from the elements of the periodic table 4a, 5a, 6a group except Si, Si, B, and Y.

(B) The compositional gradient type (Al, Cr) N layer (hereinafter referred to as composition gradient AlCrN layer) or the compositional gradient type (Al, Cr, M) N layer (hereinafter referred to as composition gradient) as the upper layer. The AlCrMN layer is an intermediate layer of the (Al, Cr) N layer or (Al, Cr, M) N layer, for example, an Al-Cr alloy or Al-Cr-M alloy having a predetermined composition is used as a cathode electrode. After vapor deposition by arc ion plating in a nitrogen atmosphere, the arc atmosphere between the cathode electrode and the anode electrode of the Al-Cr alloy or Al-Cr-M alloy is continued, By gradually reducing the nitrogen content ratio, a composition gradient AlCrN layer or a composition gradient AlCrMN layer having an average layer thickness of 0.3 to 1 μm and a small nitrogen content ratio on the upper layer surface It can be easily deposited form.

(C) Further, it comprises a lower layer made of an (Al, Ti) N layer, an intermediate layer made of an (Al, Cr) N layer or (Al, Cr, M) N layer, a composition gradient AlCrN layer or a composition gradient AlCrMN layer. In the coated tool of the present invention in which the upper layer is formed by vapor deposition, Al, which is a constituent component of the lower layer of the hard coating layer, improves high-temperature hardness and heat resistance, and Ti improves high-temperature strength. As a result, (Al, The lower layer made of Ti) N layer has excellent high-temperature hardness and high-temperature strength, so it has excellent fracture resistance, and the intermediate layer of the hard coating layer has excellent high-temperature hardness and high-temperature strength. In addition, the composition gradient AlCrN layer or the composition gradient AlCrMN layer, which is the upper layer, has excellent thermal conductivity, heat dissipation, and lubricity, so that the hard coating layer is not overheated and the work material Yo With welded against the cutting edge surface of the chips is significantly reduced, thermal plastic deformation, the occurrence of uneven wear is suppressed.
Therefore, the coated tool of the present invention is made of a work material having a high weldability such as mild steel and stainless steel, which has high heat generation and high-speed heavy load such as high feed and high cut that cause a high load on the cutting edge. Demonstrate excellent fracture resistance and excellent wear resistance over a long period of use even when cutting under cutting conditions.

This invention has been made based on the above findings,
“(1) On the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
(A) As a lower layer, it has an average layer thickness of 0.5 to 5 μm,
Composition _{formula: (Al 1-X Ti X} ) N
The composite nitride layer of Al and Ti having an average composition satisfying 0.3 ≦ X ≦ 0.7 (where X value is an atomic ratio),
(B) As an intermediate layer, it has an average layer thickness of 0.5 to 5 μm,
Composition formula: (Al _1-P Cr _P ) N _Q
The composite nitride layer of Al and Cr having an average composition satisfying 0.2 ≦ P ≦ 0.6 and 0.9 ≦ Q <1 (where both P value and Q value are atomic ratios) ,
(C) As an upper layer, it has an average layer thickness of 0.3-1 μm,
Composition formula: (Al _1-α Cr _α ) N _β
, The average composition ratio of Al and Cr satisfying 0.2 ≦ α ≦ 0.6 (where the α value is an atomic ratio), and the nitrogen content ratio (β value in the upper layer. , Atomic ratio) decreases from the intermediate layer side toward the upper layer surface, and the nitrogen content (β value) on the upper layer surface satisfies 0 ≦ β ≦ 0.35 Composition-graded Al and Cr composite nitride layer,
The surface coating cutting tool provided with the hard coating layer comprised by said (a)-(c).
(2) On the surface of the tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
(A) As a lower layer, it has an average layer thickness of 0.5 to 5 μm,
Composition _{formula: (Al 1-X Ti X} ) N
The composite nitride layer of Al and Ti having an average composition satisfying 0.3 ≦ X ≦ 0.7 (where X value is an atomic ratio),
(B) As an intermediate layer, it has an average layer thickness of 0.5 to 5 μm,
Composition _{formula: (Al 1-R-S} Cr R M S) N T ( where, M is chosen Periodic Table 4a except Cr, 5a, elements of Group 6a, Si, B, from among Y 1 or 2 or more additional components)
0.10 ≦ R ≦ 0.54, 0.01 ≦ S ≦ 0.25, 0.2 ≦ R + S ≦ 0.6, 0.9 ≦ T <1 (however, R value, S value) , T values are all atomic ratios) and an average composition Al, Cr, and M composite nitride layer,
(C) As an upper layer, it has an average layer thickness of 0.3-1 μm,
Composition formula: (Al _1-γ-δ Cr _γ M _δ ) N _ε (where M is selected from the elements of groups 4a, 5a, and 6a of the periodic table excluding Cr, Si, B, and Y) 1 or 2 or more additional components)
0.10 ≦ γ ≦ 0.54, 0.01 ≦ δ ≦ 0.25, 0.2 ≦ γ + δ ≦ 0.6 (however, both γ and δ values are atomic ratios) And an average composition ratio of Al, Cr, and M, and a concentration distribution structure in which the nitrogen content ratio (ε value, but the atomic ratio) in the upper layer decreases from the intermediate layer side toward the upper layer surface. In addition, a composition-graded Al and Cr composite nitride layer in which the nitrogen content (ε value) on the upper layer surface satisfies 0 ≦ ε ≦ 0.35,
The surface coating cutting tool provided with the hard coating layer comprised by said (a)-(c).
(3) In the surface-coated cutting tool according to (1) or (2),
As the outermost surface layer, it has an average layer thickness of 0.2 to 0.6 μm,
Composition _{formula: (Al 1-X Ti X} ) N
In other words, a composite nitride layer of Al and Ti having an average composition satisfying 0.3 ≦ X ≦ 0.7 (where X value is an atomic ratio) is further deposited on the surface of the upper layer. The surface-coated cutting tool according to (1) or (2), which is characterized in that "
It has the characteristics.

  Next, each layer of the coated tool of the present invention will be described in detail.

(A) Lower layer The Al component in the lower layer of the hard coating layer composed of a composite nitride layer of Al and Ti ((Al, Ti) N layer) improves the high-temperature hardness and heat resistance, while the Ti component Has the effect of improving the high-temperature strength, the lower layer increases the content ratio of the Al component and has a high high-temperature hardness, but the average composition of the lower layer,
Composition _{formula: (Al 1-X Ti X} ) N
When the X value indicating the Ti content in the total amount with Al is less than 0.3 (atomic ratio, the same shall apply hereinafter), the proportion of Al is relatively high and excellent high temperature. Although hardness is obtained, sufficient high-temperature strength cannot be ensured, so that the fracture resistance is lowered. On the other hand, when the X value indicating the ratio of Ti exceeds 0.7, Since the ratio of Al becomes too small, the high-temperature hardness rapidly decreases, and as a result, the progress of wear is rapidly accelerated. Therefore, the X value is set to 0.3 to 0.7.
Further, if the average layer thickness is less than 0.5 μm, the excellent high-temperature hardness and high-temperature strength cannot be imparted to the hard coating layer over a long period of time, resulting in a short tool life. When the thickness exceeds 5 μm, chipping is likely to occur. Therefore, the average thickness of the lower layer is set to 0.5 to 5 μm.

(B) Intermediate layer The intermediate layer is a composite nitride layer of Al and Cr ((Al, Cr) N layer) or a composite nitride layer of Al, Cr and M ((Al, Cr, M) N layer, where , M is an element of the periodic table 4a, 5a, 6a excluding Cr, or one or more additive components selected from Si, B, and Y.) The Al component has the effect of improving the high temperature hardness and heat resistance, the Cr component has the effect of improving the high temperature strength, and the coexistence of Cr and Al improves the high temperature oxidation resistance. Of these, the elements of the periodic tables 4a, 5a and 6a excluding Cr, Si and B, have the effect of improving the wear resistance of the hard coating layer, and Y represents the high temperature acid resistance of the hard coating layer. There is an effect of improving the chemical properties.

(B-1) When the intermediate layer is formed of an (Al, Cr) N layer not containing an M component,
The average composition of the intermediate layer is
Composition formula: (Al _1-P Cr _P ) N _Q
When the P value (atomic ratio) indicating the content ratio of Cr in the total amount with Al is less than 0.2, it is the minimum necessary for high-speed heavy cutting of work material with high weldability It is not possible to ensure the high-temperature strength that is assumed, and defects are likely to occur. On the other hand, if the P value (atomic ratio) exceeds 0.6, the high Al hardness decreases due to a decrease in the relative Al content. Since the heat resistance is lowered and the improvement of the wear resistance cannot be expected due to the occurrence of uneven wear, the occurrence of thermoplastic deformation, etc., the Cr content in the total amount with Al (P value) (however, the atomic ratio ) Was defined as 0.2 ≦ P ≦ 0.6.
When the total amount of the metal components Al and Cr in the intermediate layer is 1, the Q value indicating the content ratio (however, atomic ratio) of the N component to these metal components is out of the range of 0.9 ≦ Q <1. Therefore, the high temperature hardness and high temperature strength required in high-speed cutting of a work material having high weldability cannot be maintained, so the content ratio (Q value) (however, the atomic ratio) of the N component is set to 0. It was determined that 9 ≦ Q <1.

(B-2) Next, when the intermediate layer is an (Al, Cr, M) N layer containing an M component,
The average composition of the intermediate layer is
Composition _{formula: (Al 1-R-S} Cr R M S) N T ( where, M is chosen Periodic Table 4a except Cr, 5a, elements of Group 6a, Si, B, from among Y 1 or 2 or more additional components)
When the R value (atomic ratio) indicating the content ratio of Cr in the total amount of Al and M is less than 0.10, the minimum in high-speed heavy cutting of a work material with high weldability Since the required high-temperature strength cannot be ensured, the chipping resistance is lowered. On the other hand, when the R value (atomic ratio) exceeds 0.54, the high-temperature hardness is reduced due to a decrease in the relative Al content. Decrease in heat resistance and heat resistance, and the improvement in wear resistance cannot be expected due to the occurrence of uneven wear and the occurrence of thermoplastic deformation. Further, when the S value (atomic ratio) indicating the content ratio of the M component in the total amount of Al and Cr is less than 0.01, characteristics such as wear resistance and high-temperature oxidation resistance due to the inclusion of the M component. On the other hand, when the S value exceeds 0.25, the high temperature strength tends to decrease and defects are likely to occur. Therefore, the R value is set to 0.10 to 0.54, and the S value is set. It was determined to be 0.01 to 0.25. Even if each of the R value and the S value is within this range, if the value of (R + S) is less than 0.2, the effect of improving wear resistance and high temperature oxidation resistance cannot be expected, while (R + S) When the value of) exceeds 0.6, the progress of wear is rapidly promoted, so the value of (R + S) is set to 0.2 ≦ R + S ≦ 0.6. When the total amount of the metal components Al, Cr, and M in the intermediate layer is 1, the T value indicating the content ratio (however, atomic ratio) of the N component to these metal components is in the range of 0.9 ≦ T <1. Since the high temperature hardness and high temperature strength required in high-speed cutting of a work material having high weldability cannot be maintained, the N component content ratio (T value) (however, the atomic ratio) is It was determined that 0.9 ≦ T <1.

(B-3) Furthermore, if the average layer thickness of the intermediate layer is less than 0.5 μm, it is insufficient to exhibit its excellent wear resistance over a long period, while the average layer thickness is 5 μm. If it exceeds the upper limit, the cutting edge portion is likely to be damaged by high-speed heavy cutting, so the average layer thickness is determined to be 0.5 to 5 μm.

(C) Upper layer The composition gradient AlCrN layer or composition gradient AlCrMN layer constituting the upper layer has a concentration distribution structure in which the N content ratio (β value, ε value) decreases from the intermediate layer side toward the upper layer surface. ing. Therefore, the upper layer in the vicinity of the intermediate layer has a composition close to the average composition of the intermediate layer, and the intermediate layer and the upper layer are formed as layers having compositional continuity. Even if it is formed in a two-layer structure, an upper layer having high bonding strength between layers and having excellent high-temperature hardness, high-temperature strength, and heat resistance is formed. On the other hand, since the N content ratio in the (Al, Cr) N layer or (Al, Cr, M) N layer decreases toward the surface side of the upper layer, the surface of the upper layer has thermal conductivity, A layer having excellent heat dissipation and excellent surface smoothness is formed, and lubricity with the work material is improved.

(C-1) When the upper layer is formed of a composition gradient AlCrN layer not containing an M component,
The composition of the upper layer,
Composition formula: (Al _1-α Cr _α ) N _β
The content ratio (α value) of Cr in the total amount of Al and Cr is 0.2 ≦ α ≦ 0.6 (provided that the α value is an atomic ratio) for the same reason as in the intermediate layer. ).
In addition, when the total amount of Al and Cr is 1 on the surface of the upper layer, if the N component content ratio (β value) exceeds 0.35, the thermal conductivity and heat dissipation on the surface of the upper layer Since the effect of improving the surface smoothness is small and, as a result, the lubricity and wear resistance with the work material are insufficient, the content ratio of the N component on the surface of the upper layer to the total amount of Al and Cr ( β value) was defined as 0 ≦ β ≦ 0.35 (where β value is an atomic ratio). Here, the value of β being 0 (zero) is nothing but the fact that the surface of the upper layer is formed of an alloy of Al and Cr rather than a composite nitride of Al and Cr. The upper layer surface is referred to as a composition gradient AlCrN layer for the sake of convenience, including not only the composite nitride of Al and Cr but also the case where it is formed of an Al—Cr alloy.

(C-2) When the upper layer is formed of a composition gradient AlCrMN layer containing an M component,
The composition of the upper layer,
Composition formula: (Al _1-γ-δ Cr _γ M _δ ) N _ε (where M is selected from the elements of groups 4a, 5a, and 6a of the periodic table excluding Cr, Si, B, and Y) 1 or 2 or more additional components)
The content ratio γ value and δ value of Al, Cr, and M are 0.10 ≦ γ ≦ 0.54, 0.01 ≦ δ ≦ 0.25, for the same reason as in the intermediate layer, 0.2 ≦ γ + δ ≦ 0.6 (however, both γ value and δ value are atomic ratios).
Further, assuming that the total amount of Al, Cr and M is 1 on the surface of the upper layer, if the N component content ratio (ε value) exceeds 0.35, the thermal conductivity, The effect of improving the dissipative property and surface smoothness is small, and as a result, the lubricity and wear resistance with the work material become insufficient, so the content of N component on the surface of the upper layer with respect to the total amount of Al and Cr The ratio (ε value) was defined as 0 ≦ ε ≦ 0.35 (where ε value is an atomic ratio). The ε value of 0 (zero) is nothing but that the upper layer surface is not made of a composite nitride of Al, Cr and M, but an alloy of Al, Cr and M. The upper layer surface is not only a composite nitride of Al, Cr, and M but also referred to as a composition-graded AlCrMN layer for convenience, including the case where it is formed of an Al—Cr—M alloy.

(C-3) When the average layer thickness of the composition gradient AlCrN layer or the composition gradient AlCrMN layer is less than 0.3 μm, it is possible to sufficiently exhibit excellent thermal conductivity, heat dissipation, and lubricity. In addition, if the average layer thickness exceeds 1 μm, welding with the work material is likely to occur, so the average layer thickness of the upper layer is determined to be 0.3 to 1 μm.

(C-4) The composition gradient type upper layer uses, for example, a cathode electrode made of an Al—Cr alloy or an Al—Cr—M alloy used for vapor deposition of the intermediate layer, and contains nitrogen in the apparatus atmosphere. Concentration at which the N content ratio decreases from the intermediate layer side toward the upper layer surface by performing arc ion plating using the Al—Cr alloy or Al—Cr—M alloy as a cathode electrode while gradually reducing the ratio. A compositionally graded AlCrN layer or a compositionally graded AlCrMN layer having a distributed structure can be formed, but it is not necessary to use the same cathode electrode used to form the intermediate layer. The upper layer can also be formed using electrodes.

(D) Outermost surface layer When the hard coating layer composed of the lower layer, the intermediate layer, and the upper layer has the same average composition as the lower layer (ie, composition formula: (Al _1-X Ti _X ) N) , 0.3 ≦ X ≦ 0.7 (where the X value is an atomic ratio satisfying the atomic ratio), and forming a thin (Al, Ti) N layer as the outermost surface layer, this outermost surface layer Can further improve the wear resistance and fracture resistance of the entire hard coating layer without impairing the properties of the intermediate layer and the upper layer. The layer thickness of the outermost surface layer needs to be 0.2 to 0.6 μm, and if the layer thickness is less than 0.2 μm, improvement in wear resistance and fracture resistance cannot be expected, On the other hand, if the layer thickness exceeds 0.6 μm, the welding resistance to the work material having high weldability is lowered, which causes a defect.

  In the coated tool of the present invention, the (Al, Ti) N layer constituting the lower layer of the hard coating layer has excellent high-temperature hardness, heat resistance, and high-temperature strength, and constitutes an intermediate layer (Al, Cr). N layer or (Al, Cr, M) N layer has excellent high temperature hardness, high temperature strength, high temperature oxidation resistance, and upper layer composition gradient AlCrN layer or composition gradient AlCrMN layer has excellent heat conduction As a whole, the hard coating layer has excellent high-temperature hardness, high-temperature strength, heat resistance, high-temperature oxidation resistance, thermal conductivity, heat dissipation, and lubricity. As a result, when work materials with high weldability such as mild steel and stainless steel are machined under high-speed heavy cutting conditions with high heat generation and high load acting on the cutting blade However, there is no thermoplastic deformation, uneven wear, or chipping in the hard coating layer. Excellent chipping resistance for a long time, is to exhibit wear resistance.

  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, after sintering, WC-based carbide with honing of R: 0.03 on the cutting edge and chip shape of ISO standard CNMG120408 Alloy tool bases A-1 to A-10 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 The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / Tool bases B-1 to B-6 made of TiCN base cermet having a chip shape of CNMG120408 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. It is mounted along the outer periphery at a position that is a predetermined distance in the radial direction from the center axis on the rotary table in the apparatus. An alloy or an Al-Cr-M alloy,
(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 and the anode electrode made of an Al—Ti alloy, and the tool base surface is 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 A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode to generate an arc discharge, and the target average shown in Tables 3 and 5 is formed on the surface of the tool base. A lower layer composed of an (Al, Ti) N layer having a composition and a target average layer thickness is formed by vapor deposition.
(D) Next, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table in a nitrogen gas atmosphere of 4 Pa, and the Al—Cr alloy or Al—Cr— An arc discharge is generated by flowing a current of 120 A between the cathode electrode (evaporation source) made of M alloy and the anode electrode, and the target average composition and target shown in Tables 3 and 5 are also formed on the surface of the lower layer. An intermediate layer composed of an (Al, Cr) N layer or (Al, Cr, M) N layer having an average layer thickness is formed by vapor deposition.
(E) Next, while continuing the arc discharge between the cathode electrode (evaporation source) made of the Al—Cr alloy or the Al—Cr—M alloy and the anode electrode, the atmosphere in the apparatus is changed from the nitrogen gas atmosphere at the same time. The cathode electrode (evaporation source) made of the above Al-Cr alloy or Al-Cr-M alloy is gradually switched to an argon gas atmosphere and finally in a nitrogen-argon mixed gas atmosphere of 0.5 Pa or an argon gas atmosphere. ) And an anode electrode to cause an arc discharge by causing a current of 120 A to flow, and an upper layer composed of a composition gradient AlCrN layer or a composition gradient AlCrMN layer having a target composition and a target average layer thickness shown in Tables 4 and 6 Vapor-deposited,
(F) Next, the atmosphere in the apparatus is switched from an argon gas atmosphere to a nitrogen gas atmosphere, and 120 A is provided between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode in a 4 Pa nitrogen gas atmosphere. To generate an arc discharge, the outermost surface layer consisting of (Al, Ti) N layers of the target average composition and target average layer thickness shown in Tables 4 and 6 is formed by vapor deposition.
The surface-coated throwaway tips (hereinafter referred to as the present invention-coated tips) 1 to 16 as the present invention-coated tools were produced, respectively.

Comparative Example 1

For comparison purposes,
(A) The tool bases A-1 to A-10 and B-1 to B-6 are ultrasonically cleaned in acetone and dried, and then the rotary table in the arc ion plating apparatus shown in FIG. Attached along the outer periphery at a position spaced apart from the upper central axis in the radial direction, and used as a cathode electrode (evaporation source) with an Al—Ti alloy and Al—Cr alloy or Al—Cr—M having a predetermined composition. Place the alloy,
(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 and the anode electrode made of an Al—Ti alloy, and the tool base surface is 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 A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode to generate an arc discharge, and the target average shown in Tables 3 and 5 is formed on the surface of the tool base. A lower layer composed of an (Al, Ti) N layer having a composition and a target average layer thickness is formed by vapor deposition.
(D) Next, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table in a nitrogen gas atmosphere of 4 Pa, and the Al—Cr alloy or Al—Cr— An arc discharge is generated by flowing a current of 120 A between the cathode electrode (evaporation source) made of M alloy and the anode electrode, and the target average composition and target shown in Tables 3 and 5 are also formed on the surface of the lower layer. Upper layer consisting of (Al, Cr) N layer or (Al, Cr, M) N layer of average layer thickness (the intermediate layer marked with (Note) in Tables 3 and 5 corresponds to this) And
Comparative surface-coated throwaway tips (hereinafter referred to as comparative coated tips) 1 to 16 as comparative coated tools were produced, respectively.

Next, in the state where each of the above various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1-16 and the comparative coated chips 1-16,
Work material: JIS / S10C round bar,
Cutting speed: 240 m / min. ,
Incision: 2.4 mm,
Feed: 0.35 mm / rev. ,
Cutting time: 10 minutes,
Dry high-speed continuous high-cutting cutting test of mild steel under the following conditions (cutting condition A) (normal cutting speed and cutting are 150 m / min. And 1.5 mm, respectively),
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 280 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.50 mm / rev. ,
Cutting time: 5 minutes,
Stainless steel dry high-speed intermittent high-feed cutting test under normal conditions (cutting condition B) (normal cutting speed and feed are 180 m / min. And 0.3 mm / rev., Respectively),
Work material: JIS / S55C round bar,
Cutting speed: 280 m / min. ,
Cutting depth: 2.5 mm,
Feed: 0.25 mm / rev. ,
Cutting time: 10 minutes,
Carbon steel dry high-speed continuous high-cut cutting test under normal conditions (cutting condition C) (normal cutting speed and cutting are 180 m / min. And 1.5 mm, respectively),
In each cutting test, the flank wear width of the cutting edge was measured. The measurement results are shown in Table 7.

As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [by mass ratio, TiC / WC = 50/50] powder, and 1 Prepare 8 μm Co powder, mix these raw material powders with the composition shown in Table 8, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and press at a pressure of 100 MPa. The green compacts were press-molded, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions Then, three types of tool base forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm are formed, and further, the three kinds of round bar sintered bodies are shown in Table 8 by grinding. 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. Under the same conditions as in Example 1, the target average composition and target average layer thickness (Al, Ti) N layer shown in Table 9 is used as the lower layer, and the target average composition and target average layer thickness (shown in Table 9) ( The Al, Cr) N layer or the (Al, Cr, M) N layer is used as an intermediate layer, and the target composition and the target average layer thickness shown in Table 10 are also used as the upper layer of the composition gradient AlCrN layer or composition gradient AlCrMN layer. Furthermore, by vapor deposition forming the (Al, Ti) N layer having the target average composition and target average layer thickness shown in Table 10 as the outermost surface layer,
The surface-coated carbide end mills (hereinafter referred to as the present invention-coated end mills) 1 to 8 as the present invention-coated tools were produced, respectively.

Comparative Example 2

For the purpose of comparison, the surface of the tool base (end mill) C-1 to C-8 was ultrasonically cleaned in acetone and dried, and one cathode electrode (evaporation source) shown in FIG. A lower layer composed of an (Al, Ti) N layer having a target average composition and a target average layer thickness shown in Table 11 under the same conditions as in Comparative Example 1 above. , Cr) N layer or (Al, Cr, M) by depositing an upper layer (corresponding to the intermediate layer in the present invention) consisting of N layer,
Comparative surface coated carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 8 as comparative coated tools were produced, respectively.

Next, of the present invention coated end mills 1-8 and comparative coated end mills 1-8,
About this invention coated end mills 1-3 and comparative coated end mills 1-3,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 90 m / min. ,
Groove depth (cut): 4.2 mm,
Table feed: 130 mm / min,
Wet high-speed high-cut groove cutting test of stainless steel under the following conditions (normal cutting speed and cutting are 50 m / min, 3 mm, respectively),
About this invention coated end mills 4-6 and comparative coated end mills 4-6,
Work material-Plane size: 100 mm x 250 mm, thickness: 50 mm JIS / S55C plate material,
Cutting speed: 180 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 420 mm / min,
Carbon steel dry high-speed high-feed groove cutting test under normal conditions (normal cutting speed and feed are 100 m / min. And 240 mm / min, respectively)
About this invention coated end mills 7 and 8 and comparative coated end mills 7 and 8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S10C plate,
Cutting speed: 160 m / min. ,
Groove depth (cut): 18 mm,
Table feed: 250 mm / min,
Dry high-speed, high-cut groove cutting test of mild steel under the conditions (normal cutting speed and cutting are 100 m / min, 12 mm, respectively)
In each high-speed 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 Tables 10 and 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 target average composition shown in Table 12 and the target average composition shown in Table 12 and the target average layer thickness (Al, Ti) N layer as the lower layer under the same conditions as in Example 1 above. Using the (Al, Cr) N layer or (Al, Cr, M) N layer having the target average layer thickness as an intermediate layer, the composition gradient AlCrN layer or the composition gradient AlCrMN layer having the target composition and the target average layer thickness shown in Table 13 are also shown. Is vapor-deposited as the upper layer, and further, (Al, Ti) N layer having the target average composition and target average layer thickness shown in Table 13 is formed as the outermost surface layer,
The surface-coated carbide drills (hereinafter referred to as the present invention-coated drills) 1 to 8 as the present invention-coated tools were produced, respectively.

Comparative Example 3

For the purpose of comparison, the surfaces of the above-mentioned tool bases (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone and dried, and the arc ion plating shown in FIG. In the same conditions as in Comparative Example 1 above, the target average composition shown in Table 14 and the target average layer thickness (Al, Ti) N layer as the lower layer were used, and the target average shown in Table 14 was also used. By vapor-depositing an upper layer (corresponding to the intermediate layer in the present invention) composed of an (Al, Cr) N layer or an (Al, Cr, M) N layer having a composition and a target average layer thickness,
Comparative 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 1-8 and comparative coated drills 1-8, for the present invention coated drills 1-3 and comparative coated drills 1-3,
Work material-Plane size: 100 mm x 250 mm, thickness: 50 mm JIS / S55C plate material,
Cutting speed: 150 m / min. ,
Feed: 0.28 mm / rev,
Hole depth: 8 mm,
Wet high-speed high-feed drilling test of carbon steel under the following conditions (normal cutting speed and feed are 80 m / min, 0.15 mm / rev, respectively)
About this invention coated drill 4-6 and comparative coated drill 4-6,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S10C plate,
Cutting speed: 140 m / min. ,
Feed: 0.40 mm / rev,
Hole depth: 15 mm,
Wet high-speed high-feed drilling test of mild steel under the conditions (normal cutting speed and feed are 80 m / min. And 0.25 mm / rev, respectively)
About this invention covering drills 7 and 8 and comparative covering drills 7 and 8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 150 m / min. ,
Feed: 0.36 mm / rev,
Hole depth: 28 mm,
Wet high-speed high-feed drilling test of stainless steel under the conditions of (normal cutting speed and feed are 80 m / min, 0.20 mm / rev, respectively),
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 13 and 14, respectively.

(Al, Ti) N constituting the lower layer of the hard coating layer of the present coated chips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated tool obtained as a result Composition of (Al, Cr) N layer or (Al, Cr, M) N layer constituting the layer, intermediate layer, (Al, Ti) N layer constituting the outermost surface layer, and comparative coating as a comparative coating tool (Al, Ti) N layer constituting the lower layer of the chips 1 to 16, the comparative coated end mills 1 to 8 and the comparative coated drills 1 to 8, and the upper layer (corresponding to the intermediate layer of the present invention) (Al, Cr) The composition of the N layer or the (Al, Cr, M) N layer was measured by energy dispersive X-ray analysis using a transmission electron microscope, and showed substantially the same composition as each target composition.
Further, the composition of the surface of the composition gradient AlCrN layer or the composition gradient AlCrMN layer constituting the upper layer of the coated tool of the present invention was measured by the energy dispersive X-ray analysis method using the transmission electron microscope, The N content ratio showed substantially the same value as the target β value and the target ε value.

  Further, when the average layer thickness of each of the layers constituting the hard coating layer of the present invention coated tool and the comparative coated tool was measured using a scanning electron microscope, the average value was substantially the same as the target layer thickness. (Average value of 5 locations) is shown.

  From the results shown in Table 7, Tables 10, 11, 13, and 14, the coated tool of the present invention is a work material with high weldability such as mild steel and stainless steel, with high heat generation and against the cutting edge. Even when machined under high-speed heavy cutting conditions in which a high load acts, the lower layer composed of the (Al, Ti) N layer having a predetermined composition has excellent high-temperature hardness, heat resistance and high-temperature strength, and has a predetermined composition The intermediate layer made of (Al, Cr) N layer or (Al, Cr, M) N layer has excellent high temperature hardness, high temperature strength and high temperature oxidation resistance, and has a composition gradient AlCrN layer or composition gradient The upper layer consisting of an AlCrMN layer exhibits particularly excellent heat conductivity and heat dissipation, prevents the hard coating layer from being overheated, suppresses the occurrence of uneven wear and thermoplastic deformation, and has excellent lubricity Defects can be generated by The hard coating layer is a lower layer composed of an (Al, Ti) N layer, an (Al, Cr) N layer, or an (Al, Cr, M) N, while exhibiting excellent wear resistance over a long period of time. In the comparative coated tool composed of the upper layer consisting of layers (corresponding to the intermediate layer of the present invention), the thermal conductivity, heat dissipation, and lubricity are insufficient. It is obvious that thermoplastic deformation, uneven wear, and the like occur, and that a defect occurs due to welding between the work material and the cutting edge, and as a result, the service life is reached in a relatively short time.

  As described above, the coated tool of the present invention is not only capable of cutting under normal conditions such as general steel and normal cast iron, but also high cutting of work materials with high weldability such as mild steel and stainless steel. Even when performed under high-speed heavy cutting conditions such as high feed and high cutting that generate heat and a high load acts on the cutting edge, it shows excellent cutting performance over a long period of time. It is possible to satisfactorily respond to the FA of the equipment, labor saving and energy saving of cutting, and cost reduction.

It is a schematic plan view of the arc ion plating apparatus used for forming a hard coating layer.

Claims (3)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) As a lower layer, it has an average layer thickness of 0.5 to 5 μm,
Composition _{formula: (Al 1-X Ti X} ) N
The composite nitride layer of Al and Ti having an average composition satisfying 0.3 ≦ X ≦ 0.7 (where X value is an atomic ratio),
(B) As an intermediate layer, it has an average layer thickness of 0.5 to 5 μm,
Composition formula: (Al _1-P Cr _P ) N _Q
The composite nitride layer of Al and Cr having an average composition satisfying 0.2 ≦ P ≦ 0.6 and 0.9 ≦ Q <1 (where both P value and Q value are atomic ratios) ,
(C) As an upper layer, it has an average layer thickness of 0.3-1 μm,
Composition formula: (Al _1-α Cr _α ) N _β
, The average composition ratio of Al and Cr satisfying 0.2 ≦ α ≦ 0.6 (where the α value is an atomic ratio), and the nitrogen content ratio (β value in the upper layer. , Atomic ratio) decreases from the intermediate layer side toward the upper layer surface, and the nitrogen content (β value) on the upper layer surface satisfies 0 ≦ β ≦ 0.35 Composition-graded Al and Cr composite nitride layer,
The surface coating cutting tool provided with the hard coating layer comprised by said (a)-(c). On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) As a lower layer, it has an average layer thickness of 0.5 to 5 μm,
Composition _{formula: (Al 1-X Ti X} ) N
The composite nitride layer of Al and Ti having an average composition satisfying 0.3 ≦ X ≦ 0.7 (where X value is an atomic ratio),
(B) As an intermediate layer, it has an average layer thickness of 0.5 to 5 μm,
Composition _{formula: (Al 1-R-S} Cr R M S) N T ( where, M is chosen Periodic Table 4a except Cr, 5a, elements of Group 6a, Si, B, from among Y 1 or 2 or more additional components)
0.10 ≦ R ≦ 0.54, 0.01 ≦ S ≦ 0.25, 0.2 ≦ R + S ≦ 0.6, 0.9 ≦ T <1 (however, R value, S value) , T values are all atomic ratios) and an average composition Al, Cr, and M composite nitride layer,
(C) As an upper layer, it has an average layer thickness of 0.3-1 μm,
Composition formula: (Al _1-γ-δ Cr _γ M _δ ) N _ε (where M is selected from the elements of groups 4a, 5a, and 6a of the periodic table excluding Cr, Si, B, and Y) 1 or 2 or more additional components)
0.10 ≦ γ ≦ 0.54, 0.01 ≦ δ ≦ 0.25, 0.2 ≦ γ + δ ≦ 0.6 (however, both γ and δ values are atomic ratios) And an average composition ratio of Al, Cr, and M, and a concentration distribution structure in which the nitrogen content ratio (ε value, but the atomic ratio) in the upper layer decreases from the intermediate layer side toward the upper layer surface. In addition, a composition-graded Al and Cr composite nitride layer in which the nitrogen content (ε value) on the upper layer surface satisfies 0 ≦ ε ≦ 0.35,
The surface coating cutting tool provided with the hard coating layer comprised by said (a)-(c). The surface-coated cutting tool according to claim 1 or 2,
As the outermost surface layer, it has an average layer thickness of 0.2 to 0.6 μm,
Composition _{formula: (Al 1-X Ti X} ) N
In other words, a composite nitride layer of Al and Ti having an average composition satisfying 0.3 ≦ X ≦ 0.7 (where X value is an atomic ratio) is further deposited on the surface of the upper layer. The surface-coated cutting tool according to claim 1 or 2, characterized in that

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