JP5445847B2 - A surface-coated cutting tool that exhibits excellent chipping and wear resistance with a high-speed heavy-cutting hard coating layer - Google Patents

Description

  The present invention relates to cutting of work materials such as mild steel, stainless steel, alloy steel, die steel, etc., with high heat generation and high feed, high cutting, high cutting speed conditions with high load acting on the cutting blade 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 when a hard coating layer is used.

  In general, surface-coated cutting tools include a throw-away tip that is detachably attached to the tip of a cutting tool for turning and planing of various steels and cast irons, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.

Further, as one of the surface-coated cutting tools, for example, a base body (hereinafter referred to as a tool base body) composed of tungsten carbide (hereinafter referred to as WC) base cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) base cermet. On the surface)
Composition formula: (Al _1-α Cr _α ) N or (Al _1-α-β Cr _α Si _β ) N (where α and β represent atomic ratios),
Or a composite nitride of Al and Cr [hereinafter referred to as (Al, Cr) N] layer or a composite nitride of Al, Cr and Si [hereinafter referred to as (Al, Cr, Si) N] layer. A coating tool formed by vapor-depositing a hard coating layer (hereinafter referred to as a conventional coating tool) is known, and in such a conventional coating tool, the (Al, Cr) N layer or (Al, The Cr, Si) N layer has high-temperature hardness and heat resistance due to the constituent Al, high-temperature strength due to the Cr, and high-temperature oxidation resistance due to the coexistence of Cr and Al, and high-temperature hardness due to the Si. Since it comes to be provided, it is also known that when this is used for continuous cutting and intermittent cutting of various general steels and ordinary cast iron, it exhibits excellent cutting performance.

  The above-mentioned coated tool is, for example, charged with the above-mentioned tool base in an arc ion plating apparatus which is a kind of physical vapor deposition apparatus, and heated in the apparatus to a temperature of, for example, 500 ° C. with a heater. An arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which an Al—Cr (—Si) alloy having a predetermined composition is set, for example, at a current of 90 A, and at the same time nitrogen as a reaction gas in the apparatus. A gas is introduced to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the above-described (Al, Cr) N layer or (Al It is also known to be produced by vapor-depositing a hard coating layer consisting of a (, Cr, Si) N layer.

Japanese Patent No. 3027502 Japanese Patent No. 3781374

  In recent years, the performance of cutting devices has been dramatically improved, while on the other hand, there has been a strong demand for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting has been performed under more severe cutting conditions. However, in the above-mentioned conventional coated tool, when this is used for cutting under normal conditions such as carbon steel and cast iron, there is no particular problem, but in particular, mild steel, stainless steel, alloy steel, When a work material such as die steel is used for cutting under high feed, high cutting and high speed heavy cutting conditions that cause high heat generation and high load on the cutting edge, in addition to high heat, As a result, chipping is likely to occur at the cutting edge where the load acts, and as a result, chipping (small chipping) is likely to occur, and the heat-resistant plastic deformation is not sufficient. Abrasion decreases Combing, at present, leading to a relatively short time service life.

  In view of the above, the inventors of the present invention, in particular, have high welding resistance and heat resistance with excellent hard coating layers in high-speed heavy cutting of work materials such as mild steel, stainless steel, alloy steel, and die steel. In order to develop a surface-coated cutting tool that exhibits conductivity, heat dissipation, heat-resistant plastic deformation, and lubricity, the following findings were obtained as a result of research focusing on the hard coating layer of the above-mentioned conventional coated tools. It was.

(A) The (Al, Cr) N layer of the conventional coated tool has high temperature hardness and heat resistance due to the Al component, high temperature strength due to the Cr component, and high temperature oxidation resistance due to the coexistence of Cr and Al. Therefore, the hard coating layer of conventional coated tools has excellent high-temperature hardness, high-temperature strength, heat resistance, and high-temperature oxidation resistance, but it cuts work materials with high weldability such as mild steel and stainless steel. In machining, high-hardness difficult-to-cut materials such as alloy steel and die steel, especially in high-feed, high-cut high-speed heavy cutting with high heat generation and high load acting on the cutting edge, Chips are easily welded, and thermal conductivity, heat dissipation, and lubricity are not sufficient, and thermoplastic deformation is likely to occur. As a result, it is difficult to suppress chipping and uneven wear.

(B) Therefore, the present inventors set the (Al, Cr) N layer as a thin layer A and thin a composite oxide layer of Al and Cr (hereinafter referred to as (Al, Cr) ₂ O ₃ layer). When the hard coating layer composed of the alternately laminated structure of the thin layer A and the thin layer B was formed by vapor deposition, the thin layer B composed of the (Al, Cr) ₂ O ₃ layer was formed with the thin layer A. It has been found that it not only has excellent adhesion but also has excellent high temperature hardness and toughness.
Further, as each component of the thin layer A and the thin layer B, a Si component is contained, the (Al, Cr, Si) N layer is a thin layer A, and a composite oxide layer of Al, Cr, and Si (hereinafter referred to as ( (Al, Cr, Si) ₂ O ₃ )) is used as the thin layer B, and a hard coating layer composed of an alternating laminated structure of the thin layer A and the thin layer B is formed by vapor deposition. ) It was found that the thin layer B composed of ₂ O ₃ layers has excellent adhesion to the thin layer A, and also has excellent heat-resistant plastic deformation in addition to excellent high-temperature hardness and toughness. .

(C) However, when the cutting conditions are more severe (for example, high feed rate with high heat generation, high cutting speed, high cutting speed), the cutting blade is subjected to a high load under high heat. Since the heat resistance of the thin layer B composed of the (Al, Cr) ₂ O ₃ layer or the (Al, Cr, Si) ₂ O ₃ layer is insufficient, the effect of suppressing the occurrence of chipping and thermoplastic deformation is It turns out that it is still not satisfactory.

(D) Therefore, the present inventors have further studied, and the (Al, Cr) N layer is the thin layer A, the (Al, Cr) ₂ O ₃ layer is the thin layer B, and the thin layer A and the thin layer are After forming a lower layer having an alternate laminated structure with B by vapor deposition, an O (oxygen) content ratio in the layer further decreases with increasing gradient of Al and Cr toward the layer surface of the upper layer. When a composite oxide layer is deposited as an upper layer, a compositionally graded (Al, Cr) ₂ O ₃ layer with a low O (oxygen) content in the vicinity of the surface layer has excellent thermal conductivity and heat dissipation. Because it has excellent lubricity with the work material with high weldability, it is a cutting of work material that is likely to be welded, and it generates high heat and high feed force that acts on the cutting edge In high-speed heavy cutting with high depth of cut, it exhibits excellent chipping resistance, and the lower layer is Since it has excellent high-temperature hardness, high-temperature strength, heat resistance, high-temperature oxidation resistance, and toughness, and the thin layer B has excellent adhesion to the thin layer A, the lower layers of the alternately laminated structure and the composition gradient type A coated tool provided with an upper layer made of (Al, Cr) ₂ O ₃ as a hard coating layer is used for a long period of time in high-speed heavy cutting of work materials that tend to cause welding such as mild steel and stainless steel. It was found that the chipping resistance was excellent.

In addition, the Si component is included as the component of each of the thin layer A and the thin layer B, and the Si component is also included as the component of the upper layer, and the (Al, Cr, Si) N layer is the thin layer A, The (Al, Cr, Si) ₂ O ₃ layer is the thin layer B, and the O (oxygen) content ratio in the layer is the upper layer on the lower layer composed of the alternately laminated structure of the thin layer A and the thin layer B. When a composite oxide layer of Al, Cr, and Si with a gradient composition structure that becomes smaller as it goes to the surface of the layer is deposited as an upper layer, it has further improved thermal plasticity in addition to thermal conductivity, heat dissipation, and lubricity. Since the coating tool has such a coating layer structure, it has excellent chipping resistance over a long period of time in high-speed heavy cutting of hard materials with high hardness such as alloy steel and die steel. It was found that it exhibits wear resistance.

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 lower layer composed of an alternating laminated structure of thin layers A and B, and an upper layer of composition gradient type In a surface-coated cutting tool formed by vapor-depositing a hard coating layer consisting of
(A) The thin layer A has an average layer thickness of 0.05 to 1.5 μm, and
Composition formula: (Al _1-α Cr _α ) N
In this case, a composite nitride layer of Al and Cr that satisfies 0.25 ≦ α ≦ 0.45 (where α is an atomic ratio),
(B) The thin layer B has an average layer thickness of 0.05 to 3.0 μm, and
Composition _{formula: (Al 1-Y Cr Y} ) 2 O 3
In this case, a composite oxide layer of Al and Cr that satisfies 0.25 ≦ Y ≦ 0.45 (where Y is an atomic ratio),
And
(C) The upper layer has an average layer thickness of 0.3-1 μm,
Composition _{formula: (Al 1-Y Cr Y} ) 1-X O X
In this case, 0 ≦ X ≦ 0.2, 0.25 ≦ Y ≦ 0.45 (provided that both X and Y are atomic ratios), and the O (oxygen) content ratio in the upper layer is A composition-graded Al and Cr composite oxide layer having a gradient composition that decreases from the lower layer side toward the upper layer surface,
A surface-coated cutting tool comprising:
(2) On the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet, a lower layer composed of an alternating laminated structure of thin layers A and B, and a composition gradient type upper layer In a surface-coated cutting tool in which a hard coating layer is formed by vapor deposition,
(A) The thin layer A has an average layer thickness of 0.05 to 1.5 μm, and
Composition _{formula: (Al 1-α-β} Cr α Si β) N
In this case, the composite nitride layer of Al, Cr, and Si satisfying 0.25 ≦ α ≦ 0.45 and 0.01 ≦ β ≦ 0.1 (where α and β are atomic ratios),
(B) The thin layer B has an average layer thickness of 0.05 to 3.0 μm, and
Composition _{formula: (Al 1-Y-Z} Cr Y Si Z) 2 O 3
In this case, the composite oxide layer of Al, Cr, and Si satisfying 0.25 ≦ Y ≦ 0.45 and 0.01 ≦ Z ≦ 0.1 (where Y and Z are atomic ratios). ,
And
(C) The upper layer has an average layer thickness of 0.3-1 μm,
Composition _{formula: (Al 1-Y-Z} Cr Y Si Z) 1-X O X
In this case, 0 ≦ X ≦ 0.2, 0.25 ≦ Y ≦ 0.45, 0.01 ≦ Z ≦ 0.1 (where X, Y, and Z are atomic ratios) are satisfied, And the O (oxygen) content ratio in the upper layer is a composition gradient type Al, Cr, and Si composite oxide layer having a gradient composition that decreases from the lower layer side toward the upper layer surface,
A surface-coated cutting tool comprising: "
It has the characteristics.

Next, the hard coating layer of the coated tool of the present invention will be described in detail.
(A) Composite nitride layer of Al and Cr (and Si) constituting the lower layer A ((Al, Cr) N layer, (Al, Cr, Si) N layer):
The Al component in the (Al, Cr) N layer or (Al, Cr, Si) N layer improves high-temperature hardness and heat resistance, the Cr component improves high-temperature strength, and further, the coexistence of Cr and Al increases the temperature. It has the effect of improving oxidation resistance, and the Si component has the effect of increasing the high temperature hardness and the heat resistant plastic deformation.
A composite nitride of Al and Cr (and Si) constituting the thin layer A,
Composition formula: (Al _1-α Cr _α ) N
Alternatively the composition _{formula: (Al 1-α-β} Cr α Si β) N
If the Cr content ratio α (atomic ratio, the same shall apply hereinafter) in the total amount of Al (and Si) is less than 0.25, the high temperature strength required at the minimum in high speed heavy cutting is ensured. On the other hand, if the Cr content ratio α (atomic ratio) in the total amount of Al (and Si) exceeds 0.45, the Al ratio becomes relatively small, and the high temperature hard As the wear resistance deteriorates due to the occurrence of uneven wear, the occurrence of uneven wear, the occurrence of thermoplastic deformation, etc., the content ratio of Cr in the total amount of Al (and Si) α The (atomic ratio) was determined to be 0.25 to 0.45.
In addition, when the Si content ratio β (atomic ratio, hereinafter the same) in the total amount of Al and Cr is less than 0.01, it is expected to improve high-temperature hardness and heat-resistant plastic deformation in high-speed heavy cutting. On the other hand, if the Si content ratio β (atomic ratio) in the total amount of Al and Cr exceeds 0.1, the ratio of Al becomes relatively small, and the high temperature hardness tends to decrease. Since the heat resistance tends to decrease and the wear resistance deteriorates due to the occurrence of uneven wear, the occurrence of thermoplastic deformation, etc., the Si content ratio β (atomic ratio) in the total amount of Al and Cr is 0.01 to 0.1.
Furthermore, if the average layer thickness of the thin layer A is less than 0.05 μm, excellent wear resistance cannot be exhibited over a long period of time, resulting in a short tool life, while the average layer thickness is 1.5 μm. If the thickness of the thin layer A exceeds 1, the average layer thickness of the thin layer A is determined to be 0.05 to 1.5 μm.

(B) Al and Cr (and Si) composite oxide layers ((Al, Cr) ₂ O ₃ layer, (Al, Cr, Si) ₂ O ₃ layer) constituting the thin layer B of the lower layer:
The (Al, Cr) ₂ O ₃ layer or the (Al, Cr, Si) ₂ O ₃ layer constituting the thin layer B of the lower layer has excellent adhesion to both the thin layer A and the upper layer. Or it has excellent high temperature hardness and toughness.
Composite nitride of Al and Cr (and Si) constituting the thin layer B,
Composition _{formula: (Al 1-Y Cr Y} ) 2 O 3
Alternatively the composition _{formula: (Al 1-Y-Z} Cr Y Si Z) 2 O 3
When the Cr content ratio Y (however, the atomic ratio) is less than 0.25, the thin layer B exhibits sufficient wear resistance in high-speed heavy cutting of a work material with high weldability. On the other hand, if Y (atomic ratio) exceeds 0.45, the toughness of the lower layer as a whole decreases, and defects are easily generated due to high loads acting on the cutting blade under high heat. The Cr content ratio Y in the thin layer B was determined to be 0.25 ≦ Y ≦ 0.45 (atomic ratio).
On the other hand, if the Si content ratio Z (atomic ratio, hereinafter the same) is less than 0.01, improvement in high-temperature hardness and heat-resistant plastic deformability cannot be expected, while the Si content ratio Z (atomic ratio) is 0. If it exceeds 1, the amount of Al becomes relatively small, and the high temperature hardness tends to decrease and the heat resistance tends to decrease, and the wear resistance deteriorates due to the occurrence of uneven wear, the occurrence of thermoplastic deformation, etc. Therefore, the Si content ratio Z (atomic ratio) was determined to be 0.01 to 0.1.
In addition, if the average layer thickness of the thin layer B is less than 0.05 μm, the above-mentioned excellent action cannot be exhibited over a long period of use, while if the average layer thickness exceeds 3.0 μm, Since a high load acting on the cutting edge makes it easy to cause defects, the average layer thickness of the thin layer B is determined to be 0.05 to 3.0 μm.

(C) Composition gradient type Al and Cr (and Si) composite oxide layer constituting the upper layer:
Composition gradient type Al and Cr composite oxide layer (hereinafter referred to as composition gradient type (Al, Cr) ₂ O ₃ layer) or composition gradient type Al, Cr and Si complex oxide layer (hereinafter referred to as composition gradient type) (Al, Cr, Si) ₂ O ₃ layer) produces high heat generation especially for hard materials with high weldability such as mild steel, stainless steel, etc., alloy steel, die steel, etc. In addition, it was provided to improve the thermal conductivity, heat dissipation, and lubricity of the hard coating layer as a whole in high-feed, high-cut, high-speed heavy cutting with a high load acting on the cutting edge. It is the upper layer.
In the vicinity of the surface of the upper layer, a composition gradient type (Al, Cr) ₂ O ₃ layer or a composition gradient type (Al, Cr, Si) ₂ O ₃ layer is formed as the upper layer so that the O (oxygen) content ratio decreases. Then, since the upper layer surface is excellent in thermal conductivity, heat dissipation, and lubricity, even when high heat is generated under conditions where a high load acts on the cutting edge, it is possible to cut a work material that is likely to be welded. As a result, the occurrence of welding of powder or the like is prevented, and as a result, excellent chipping resistance is exhibited even in high-feed, high-feed, high-speed heavy cutting.

The average composition in the entire upper layer of the composition gradient type (Al, Cr) ₂ O ₃ layer and the composition gradient type (Al, Cr, Si) ₂ O ₃ layer,
Composition _{formula: (Al 1-Y Cr Y} ) 1-X O X
Alternatively the composition _{formula: (Al 1-Y-Z} Cr Y Si Z) 1-X O X
When the O (oxygen) content ratio X (however, the atomic ratio) with respect to the total content of the Al component and the Cr component (and the Si component) exceeds 0.2, mild steel, stainless steel, alloy steel, The slipperiness with work materials such as die steel tends to decrease, and the thermal conductivity and heat dissipation also tend to decrease. As a result, the effect of improving chipping resistance is not sufficiently exhibited. The (oxygen) content ratio X (however, the atomic ratio) was defined as 0 ≦ X ≦ 0.2.
Moreover, by adopting a gradient composition structure in which the O (oxygen) content ratio in the upper layer decreases from the intermediate layer side toward the upper layer surface, the high temperature hardness, toughness, etc. of the upper layer are not significantly reduced. It is possible to ensure excellent lubricity with the work material on the surface of the upper layer.
Further, if the Cr content ratio Y (however, the atomic ratio) occupies the total amount of Al (and Si) is less than 0.25, as in the case of the thin layer B, sufficient wear resistance in high-speed heavy cutting. On the other hand, if Y (atomic ratio) exceeds 0.45, the toughness of the upper layer is reduced, and defects are likely to occur due to a high load acting on the cutting blade under high heat. Therefore, the Cr content ratio Y in the upper layer was determined to be 0.25 ≦ Y ≦ 0.45 (atomic ratio).
In addition, when the content ratio Z (however, the atomic ratio) of Si in the total amount of Al and Cr is less than 0.01, sufficient heat-resistant plastic deformability can be obtained in high-speed heavy cutting as in the case of the thin layer B. On the other hand, if Z (atomic ratio) exceeds 0.1, the toughness of the upper layer is reduced, and defects are likely to occur due to the high load acting on the cutting blade under high heat. The Si content ratio Z in the upper layer was determined to be 0.01 ≦ Z ≦ 0.1 (atomic ratio).
Furthermore, when the average layer thickness of the composition gradient type (Al, Cr) ₂ O ₃ layer and the composition gradient type (Al, Cr, Si) ₂ O ₃ layer is less than 0.3 μm, the work material can be used over a long period of use. The excellent lubricity, thermal conductivity, and heat dissipation properties cannot be ensured, and on the other hand, if the average layer thickness exceeds 1 μm, the high load acting on the cutting blade tends to cause defects. The average layer thickness of the upper layer composed of the gradient type (Al, Cr) ₂ O ₃ layer or the composition gradient type (Al, Cr, Si) ₂ O ₃ layer was determined to be 0.3 to 1 μm.

(D) Evaporation formation of hard coating layer The hard coating layer consisting of the lower layer composed of the alternately laminated structure of the present invention and the upper layer of the composition gradient type is formed by an ordinary physical vapor deposition apparatus (for example, arc ion plating (hereinafter referred to as AIP). ) Equipment).
For example, one of the AIP devices is provided with a cathode electrode made of a Ti electrode for substrate cleaning, and the other with a cathode electrode made of an Al—Cr (—Si) alloy,
First, for example, a tool base made of tungsten carbide base cemented carbide is cleaned and dried, mounted on a rotary table in an AIP apparatus, and an arc discharge is generated between the Ti electrode for cleaning the base and the anode electrode. Bombard the tool substrate surface,
Next, nitrogen gas is introduced as a reaction gas into the apparatus, and while applying a bias voltage to the tool base, an arc discharge is generated between the Al—Cr (—Si) alloy cathode electrode and the anode electrode, and the tool base surface (Al, Cr) N layer or (Al, Cr, Si) N layer having a predetermined thickness is deposited as a lower layer A,
Next, an atmospheric gas containing oxygen as a reaction gas is introduced into the apparatus to generate an arc discharge between the Al—Cr (—Si) alloy cathode electrode and the anode electrode, and a predetermined layer thickness is formed on the surface of the tool substrate. (Al, Cr) ₂ O ₃ layer or (Al, Cr, Si) ₂ O ₃ layer is vapor-deposited as a lower layer B,
After repeating the alternate lamination of the thin layer A and the thin layer B until the predetermined total layer thickness of the lower layer is reached, and forming the thin layer B having a predetermined layer thickness as the outermost surface of the lower layer,
By gradually reducing the oxygen content in the atmospheric gas while maintaining the arc discharge between the Al—Cr (—Si) alloy cathode electrode and the anode electrode, the oxygen content ratio is changed from the intermediate layer side to the upper layer surface layer. The upper layer composed of a composition gradient type (Al, Cr) ₂ O ₃ layer or a composition gradient type (Al, Cr, Si) ₂ O ₃ layer having a predetermined layer thickness that gradually decreases as it goes to the layer is formed by vapor deposition. it can.

The surface-coated cutting tool of the present invention includes a thin layer A composed of an (Al, Cr) N layer or (Al, Cr, Si) N layer, and an (Al, Cr) ₂ O ₃ layer or (Al, Cr, Si). _Since the lower layer of the hard coating layer is formed as an alternate laminated structure with the thin layer B composed of ₂ O ₃ layers, the lower layer has excellent high temperature hardness, high temperature strength, high temperature oxidation resistance, toughness, heat plasticity In addition to being deformable, it has excellent adhesiveness in alternating layers, and from the composition gradient type (Al, Cr) ₂ O ₃ layer or composition gradient type (Al, Cr, Si) ₂ O ₃ layer formed thereon. Because the upper layer has excellent high-temperature hardness and toughness, as well as excellent slipperiness with highly weldable work materials, and also has excellent thermal conductivity and heat dissipation, Work material with high weldability such as stainless steel, alloy steel, die Exhibits excellent chipping resistance and wear resistance in high-hardness difficult-to-cut materials such as steel, especially in high-feed, high-cutting high-speed heavy cutting with high load acting on the cutting edge under high heat generation conditions As a result, it exhibits excellent cutting performance over a long period of use.

  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 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. 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, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. Tool bases B-1 to B-6 made of TiCN-based cermet having the following chip shape were formed.

(A) Each of the tool bases A-1 to A-10 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, on a rotary table of an AIP device (not shown). Attached along the outer periphery at a position that is a predetermined distance in the radial direction from the central axis of the electrode, a Ti cathode electrode (evaporation source) for bombard cleaning is placed on one side of the AIP apparatus, and Al—Cr (− Si) alloy cathode electrode (evaporation source),
(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 Ti cathode electrode and the anode electrode to generate an arc discharge, thereby bombarding the tool base surface.
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and An arc discharge is generated by flowing a current of 100 A between the Al—Cr alloy cathode electrode and the anode electrode, so that the target composition and target layer average layer thickness shown in Tables 3 to 6 are formed on the surface of the tool base ( A thin layer A composed of an Al, Cr) N layer or an (Al, Cr, Si) N layer is formed by vapor deposition.
(D) Next, oxygen gas is introduced as a reaction gas into the apparatus to make a reaction atmosphere of 1 Pa, and a DC bias voltage of −100 V is applied to a tool base that rotates while rotating on the rotary table, An arc discharge is generated by passing a current of 100 A between the Al—Cr (—Si) alloy cathode electrode (evaporation source) and the anode electrode, and the target composition shown in Tables 3 to 6 and A thin layer B composed of (Al, Cr) ₂ O ₃ layer or (Al, Cr, Si) ₂ O ₃ layer having a target single layer average layer thickness is deposited,
(E) The above (c) and (d) are repeated so that the thin layer B becomes the outermost surface of the lower layer, and the thin layer A and the target average layer thickness shown in Tables 3 to 6 are obtained. Forming a lower layer consisting of alternating layers of thin layers B;
(F) Next, while maintaining the arc discharge between the Al—Cr (—Si) alloy cathode electrode (evaporation source) and the anode electrode, the atmosphere was adjusted so that the oxygen content was gradually reduced. Form an upper layer composed of a composition gradient type (Al, Cr) ₂ O ₃ layer or a composition gradient type (Al, Cr, Si) ₂ O ₃ layer having a target average layer thickness and a target oxygen content ratio X value shown in -6 By doing
Surface-coated throwaway tips (hereinafter referred to as the present invention-coated tips) 1 to 16 and 21 to 36 as the present invention-coated tools were produced, respectively.

Comparative Example 1:
For the purpose of comparison, these tool bases A-1 to A-10 and B-1 to B-6 were ultrasonically washed in acetone and dried, and then loaded into the AIP apparatus shown in FIG.
First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then a DC bias voltage of −1000 V is applied to the tool base that rotates while rotating on the rotary table. And applying an electric current of 100 A between the Ti cathode electrode and the anode electrode to generate an arc discharge, thereby bombarding the tool substrate surface,
Next, nitrogen gas is introduced as a reaction gas into the apparatus to make a reaction atmosphere of 3 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and Al—Cr An arc discharge is generated by flowing a current of 100 A between the (-Si) alloy cathode electrode and the anode electrode, and the target composition and target layer thickness (Al) shown in Tables 7 and 8 are formed on the surface of the tool base. , Cr) N layer or (Al, Cr, Si) N layer (corresponding to the composition of the thin layer A in the present invention) is deposited,
Surface coated throwaway tips (hereinafter referred to as comparative coated tips) 1 to 16 and 21 to 36 as comparative coated tools were produced, respectively.

Next, in the state where all the above-mentioned various coated tips are screwed to the tip of the tool steel tool with a fixing jig, first, for the present coated chips 1-16 and the comparative coated chips 1-16,
Work material: JIS / S10C round bar,
Cutting speed: 250 m / min. ,
Cutting depth: 2.5 mm,
Feed: 0.48 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed high-feed / high-cut cutting test of mild steel under the above conditions (referred to as cutting condition A) (normal cutting speed, feed and cutting are 150 m / min, 0.25 mm / rev, and 1.5 mm, respectively) ,
Work material: JIS / S55C lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 220 m / min. ,
Cutting depth: 1.5 mm,
Feed: 0.50 mm / rev. ,
Cutting time: 5 minutes,
Of carbon steel under the following conditions (referred to as cutting condition B) (in normal cutting speed and feed are 120 m / min and 0.25 mm / rev, respectively),
Work material: JIS / SUS304 round bar,
Cutting speed: 240 m / min. ,
Incision: 2.8 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
Stainless steel dry continuous high-speed high-cut cutting test under normal conditions (referred to as cutting condition C) (normal cutting speed and cutting are 120 m / min and 1.5 mm, respectively),
The flank wear width of the cutting edge was measured in any high speed heavy cutting test. The measurement results are shown in Table 9.

Similarly, for the inventive coated chips 21-36 and the comparative coated chips 21-36,
Work material: JIS / S55C round bar,
Cutting speed: 270 m / min. ,
Incision: 2.7 mm,
Feed: 0.50 mm / rev. ,
Cutting time: 10 minutes,
(Continuous cutting speed, feed and cutting are 150 m / min, 0.25 mm / rev, and 1.5 mm, respectively) ),
Work material: JIS / SUS304 lengthwise equidistant 4 round grooved round bars
Cutting speed: 240 m / min. ,
Cutting depth: 1.8 mm,
Feed: 0.50 mm / rev. ,
Cutting time: 5 minutes,
(Continuous cutting speed and feed are 120 m / min and 0.25 mm / rev., Respectively)
Work material: JIS / S10C round bar,
Cutting speed: 240 m / min. ,
Cutting depth: 3.0 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 10 minutes,
Dry continuous high-speed high-cut cutting test of mild steel under the following conditions (referred to as cutting conditions F) (normal cutting speed and cutting are 150 m / min and 1.5 mm, respectively),
The flank wear width of the cutting edge was measured in any high speed heavy cutting test. The measurement results are shown in Table 10.

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, and each of these raw material powders was blended in the blending composition shown in Table 11, 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, baked under furnace cooling conditions Then, three types of round rod sintered bodies for forming a tool base having a diameter of 8 mm, 13 mm, and 26 mm were formed, and further, the above three types of round rod sintered bodies were ground and shown in Table 10. WC-based cemented carbide with a 4-blade square shape with a cutting blade portion diameter × length of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, and a twist angle of 30 degrees. Tool bases (end mills) C-1 to C-8 were manufactured.

Next, the surfaces of these tool bases (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged in the same AIP apparatus, under the same conditions as in Example 1 above. A thin layer A composed of an (Al, Cr) N layer or (Al, Cr, Si) N layer having a target composition and a target layer thickness shown in Tables 12 and 13, and an (Al, Cr) ₂ O ₃ layer or (Al , Cr, Si) ₂ O ₃ layers are formed as an alternating layered structure of thin layers B, and the lower layer is formed. Further, the composition gradient type of the target average layer thickness and target oxygen content ratio X value shown in Tables 12 and 13 is used. By forming an upper layer consisting of (Al, Cr) ₂ O ₃ layer or composition gradient type (Al, Cr, Si) ₂ O ₃ layer,
Super coated end mills of the present invention (hereinafter referred to as the present coated end mills) 1 to 8 and 11 to 18 as the coated tools of the present invention were produced, respectively.

Comparative Example 2:
For the purpose of comparison, the surfaces of the tool bases (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and charged in the same AIP apparatus. Under conditions, the (Al, Cr) N layer or (Al, Cr, Si) N layer (corresponding to the composition of the thin layer A in the present invention) having the target average layer thickness and the target composition shown in Table 14 is deposited. By
Comparative coated end mills (hereinafter referred to as comparative coated end mills) 1 to 8 and 11 to 18 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: 140 m / min. ,
Groove depth (cut): 5 mm,
Table feed: 120 mm / min,
Wet high-speed, high-cut groove cutting test of stainless steel under the conditions (normal cutting speed and cutting are 80 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): 8 mm,
Table feed: 400 mm / min,
Carbon steel dry high-speed high-cut groove cutting test under normal conditions (normal cutting speed and cutting are 100 m / min, 5 mm, respectively),
For the coated end mills 7 and 8 and the comparative coated end mills 7 and 8 of the present invention,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S10C plate,
Cutting speed: 160 m / min. ,
Groove depth (cut): 16 mm,
Table feed: 250 mm / min,
Dry high-speed high-cut groove cutting test of mild steel under the conditions of (normal cutting speed and cutting is 100 m / min, 10 mm, respectively),
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, in any high-speed, high-cut groove cutting test. The measurement results are shown in Tables 12 and 14, respectively.

Similarly, of the present invention coated end mills 11-18 and comparative coated end mills 11-18,
About the present invention coated end mills 11-13 and comparative coated end mills 11-13,
Work material-Plane size: 100 mm x 250 mm, thickness: 50 mm JIS / S55C plate material,
Cutting speed: 160 m / min. ,
Groove depth (cut): 5.5 mm,
Table feed: 120 mm / min,
Carbon steel dry high-speed high-cut groove cutting test under normal conditions (normal cutting speed and cutting are 80 m / min, 3 mm, respectively),
About this invention coated end mills 14-16 and comparative coated end mills 14-16,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / S10C plate,
Cutting speed: 200 m / min. ,
Groove depth (cut): 9 mm,
Table feed: 400 mm / min,
Dry high-speed high-cut groove cutting test of mild steel under the conditions of (normal cutting speed and cutting is 100 m / min., 5 mm., Respectively),
For the coated end mills 17 and 18 of the present invention and the comparative coated end mills 17 and 18,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 180 m / min. ,
Groove depth (cut): 18 mm,
Table feed: 250 mm / min,
Wet high-speed high-cut groove cutting test of stainless steel under the following conditions (normal cutting speed and cutting are 100 m / min, 10 mm, respectively),
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, in any high-speed, high-cut groove cutting test. The measurement results are shown in Tables 13 and 14, 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 honed, ultrasonically cleaned in acetone, and placed in an AIP apparatus in a dry state. Under the same conditions, the (Al, Cr) N layer or (Al, Cr, Si) N layer and the (Al, Cr) ₂ O ₃ layer or (Al , Cr, Si) ₂ O ₃ layers are alternately formed as a lower layer, and further, composition gradient type (Al, Cr) of the target average layer thickness and target oxygen content ratio X value shown in Tables 15 and 16 are used. ) By forming an upper layer composed of a ₂ O ₃ layer or a composition gradient type (Al, Cr, Si) ₂ O ₃ layer,
Invention coated drills (hereinafter referred to as the present invention coated drills) 1 to 8 and 11 to 18 as the present coated tools were produced, respectively.

Comparative Example 3:
For the purpose of comparison, honing is performed on the surfaces of the above-mentioned tool bases (drills) D-1 to D-8, ultrasonic cleaning is performed in acetone, and the dried state is inserted into an AIP apparatus. (Al, Cr) N layer or (Al, Cr, Si) N layer (corresponding to the composition of thin layer A in the present invention) having the target average layer thickness and target composition shown in Table 17 under the same conditions as in Table 1. By evaporating
Comparative coated drills (hereinafter referred to as comparative coated drills) 1 to 8 and 11 to 18 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: 120 m / min. ,
Feed: 0.30 mm / rev,
Hole depth: 8 mm,
Wet high-speed high-feed drilling test of carbon steel under the conditions (normal cutting speed and feed are 80 m / min. And 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: 0.45 mm / rev,
Hole depth: 15 mm,
Wet high-speed high-feed drilling test of mild steel under the following 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: 120 m / min. ,
Feed: 0.40 mm / rev,
Hole depth: 28 mm,
Wet high-speed high-feed drilling test of stainless steel under the conditions (normal cutting speed and feed are 80 m / min. And 0.25 mm / rev, respectively)
In each wet high-speed high-feed 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 15 and 17, respectively.

Similarly, of the present invention coated drills 11-18 and comparative coated drills 11-18, the present invention coated drills 11-13 and comparative coated drills 11-13 are:
Work material-planar dimension: 100 mm × 250 mm, thickness: 50 mm S10C plate,
Cutting speed: 150 m / min. ,
Feed: 0.32 mm / rev,
Hole depth: 8 mm,
Wet high-speed high-feed drilling test of mild steel under the conditions (normal cutting speed and feed are 80 m / min, 0.15 mm / rev, respectively)
About this invention coated drills 14-16 and comparative coated drills 14-16,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Cutting speed: 160 m / min. ,
Feed: 0.50 mm / rev,
Hole depth: 15 mm,
Wet high-speed high-feed drilling test of stainless steel under the conditions (normal cutting speed and feed are 80 m / min. And 0.25 mm / rev, respectively)
About this invention covering drills 17 and 18 and comparative covering drills 17 and 18,
Work material-Plane size: 100 mm x 250 mm, thickness: 50 mm JIS / S55C plate material,
Cutting speed: 150 m / min. ,
Feed: 0.45 mm / rev,
Hole depth: 28mm,
Wet high-speed high-feed drilling test of carbon steel under the conditions (normal cutting speed and feed are 80 m / min. And 0.25 mm / rev, respectively)
In each wet high-speed high-feed 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 16 and 17, respectively.

(Al, Cr) N layers and (Al, Cr) ₂ O ₃ N layers constituting an alternate lamination of the lower layers of the hard coating layer of the present coated tip, the present coated end mill, and the present coated drill obtained as a result. [Or (Al, Cr, Si) N layer, (Al, Cr, Si) ₂ O ₃ N layer composition]], and comparative coated tip, comparative coated end mill, and hard coated layer of a comparative coated drill (the present invention) (Al, Cr) N layer composition (or (Al, Cr, Si) N layer composition), the above-described coated tip of the present invention, the coated end mill of the present invention, and the coated drill of the present invention. The composition of the composition gradient type (Al, Cr) ₂ O ₃ layer constituting the upper layer of the hard coating layer [or the composition of the composition gradient type (Al, Cr, Si) ₂ O ₃ layer] is measured using a transmission electron microscope. Measured by energy dispersive X-ray analysis When the showed substantially the same composition as the respective target composition.
Moreover, the change of the O (oxygen) content ratio in the composition gradient type (Al, Cr) ₂ O ₃ layer in the layer thickness direction of the upper layer of the hard coating layer of the present coated tip, the present coated end mill, and the present coated drill For [or change in O (oxygen) content ratio in composition gradient type (Al, Cr, Si) ₂ O ₃ layer], the O (oxygen) content ratio toward the upper surface layer by Auger spectroscopy Was confirmed to be reduced.

  Moreover, when the average layer thickness of each constituent layer of the hard coating layer of the present invention coated tool and the comparative coated tool was measured by cross-section using a scanning electron microscope, the average value was substantially the same as the target layer thickness ( Average value of 5 locations).

From the results shown in Tables 9, 10, and 12-17, the coated tool of the present invention has an alternate laminated structure of (Al, Cr) N layers and (Al, Cr) ₂ O ₃ layers [or (Al, Cr, Si). ) N layer and (Al, Cr, Si) ₂ O ₃ layer alternately layered structure] lower layer has excellent high temperature hardness, heat resistance, high temperature strength, toughness, heat resistance plastic deformation and thin layer An upper portion having excellent interlayer adhesion between the A-thin layer B and further comprising a composition gradient type (Al, Cr) ₂ O ₃ layer [or composition gradient type (Al, Cr, Si) ₂ O ₃ layer] In addition to excellent thermal conductivity and heat dissipation, the layer is also excellent in lubricity with work materials with high weldability, so it has high weldability such as mild steel and stainless steel. High-hardness difficult-to-cut materials such as steel, alloy steel, die steel, etc., especially high loads on the cutting edge under high heat conditions Even when used for high-feed, high-cutting high-speed heavy cutting, it has excellent chipping resistance and wear resistance, whereas the hard coating layer is an (Al, Cr) N layer [or (Al , Cr, Si) N layer]], it is easy to generate welding due to insufficient lubricity with the work material, and heat resistance is not sufficient, resulting in chip welding. It is clear that the service life is reached in a relatively short time due to occurrence of chipping and uneven wear.

  As described above, the coated tool of the present invention can be used not only for cutting under normal conditions such as general steel and ordinary cast iron, but also for high-speed heavy cutting such as work materials with high weldability and hard hard-to-cut materials. Since it shows excellent cutting performance over a long period of time, it can satisfactorily cope with the FA of the cutting apparatus, labor saving and energy saving of cutting, and cost reduction.

Claims (2)

Hard coating comprising a lower layer composed of alternating layers of thin layer A and thin layer B and an upper layer of composition gradient type on the surface of a tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet In a surface-coated cutting tool in which a layer is formed by vapor deposition,
(A) The thin layer A has an average layer thickness of 0.05 to 1.5 μm, and
Composition formula: (Al _1-α Cr _α ) N
In this case, a composite nitride layer of Al and Cr that satisfies 0.25 ≦ α ≦ 0.45 (where α is an atomic ratio),
(B) The thin layer B has an average layer thickness of 0.05 to 3.0 μm, and
Composition _{formula: (Al 1-Y Cr Y} ) 2 O 3
In this case, a composite oxide layer of Al and Cr that satisfies 0.25 ≦ Y ≦ 0.45 (where Y is an atomic ratio),
And
(C) The upper layer has an average layer thickness of 0.3-1 μm,
Composition _{formula: (Al 1-Y Cr Y} ) 1-X O X
In this case, 0 ≦ X ≦ 0.2, 0.25 ≦ Y ≦ 0.45 (provided that both X and Y are atomic ratios), and the O (oxygen) content ratio in the upper layer is A composition-graded Al and Cr composite oxide layer having a gradient composition that decreases from the lower layer side toward the upper layer surface,
A surface-coated cutting tool comprising: Hard coating comprising a lower layer composed of alternating layers of thin layer A and thin layer B and an upper layer of composition gradient type on the surface of a tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet In a surface-coated cutting tool in which a layer is formed by vapor deposition,
(A) The thin layer A has an average layer thickness of 0.05 to 1.5 μm, and
Composition _{formula: (Al 1-α-β} Cr α Si β) N
In this case, the composite nitride layer of Al, Cr, and Si satisfying 0.25 ≦ α ≦ 0.45 and 0.01 ≦ β ≦ 0.1 (where α and β are atomic ratios),
(B) The thin layer B has an average layer thickness of 0.05 to 3.0 μm, and
Composition _{formula: (Al 1-Y-Z} Cr Y Si Z) 2 O 3
In this case, the composite oxide layer of Al, Cr, and Si satisfying 0.25 ≦ Y ≦ 0.45 and 0.01 ≦ Z ≦ 0.1 (where Y and Z are atomic ratios). ,
And
(C) The upper layer has an average layer thickness of 0.3-1 μm,
Composition _{formula: (Al 1-Y-Z} Cr Y Si Z) 1-X O X
In this case, 0 ≦ X ≦ 0.2, 0.25 ≦ Y ≦ 0.45, 0.01 ≦ Z ≦ 0.1 (where X, Y, and Z are atomic ratios) are satisfied, And the O (oxygen) content ratio in the upper layer is a composition gradient type Al, Cr, and Si composite oxide layer having a gradient composition that decreases from the lower layer side toward the upper layer surface,
A surface-coated cutting tool comprising: