JP3985411B2 - Cutting tool made of surface-coated cemented carbide with excellent wear resistance - Google Patents

Description

【００１７】
【表２】

【００１８】
【表３】

【００１９】
【表４】

【００２０】
【表５】

【００２１】
【発明の効果】
表３〜５に示される結果から、本発明被覆超硬切削工具１〜１３は、いずれも耐摩耗性被覆層を構成するＡｌ₂ Ｏ₃ 主体層がＡｌに比してイオン半径の著しく大きいＴｉ、Ｚｒ、およびＨｆのうちの１種以上を置換含有し、これによって著しく高い圧縮残留応力を保持するようになって、強靭性被覆層を構成する（Ｔｉ，Ａｌ）Ｎ層および（Ｔｉ，Ａｌ）ＣＮ層に対して強固に密着するようになるので、鋼の断続切削を高切込みおよび高送りの重切削条件で行っても前記Ａｌ₂ Ｏ₃ 主体層に剥離の発生なく、すぐれた耐摩耗性を発揮するのに対して、従来被覆超硬切削工具１〜１３は、いずれもこれの強靭性被覆層の耐摩耗性不足が原因で、上記のような苛酷な条件下では摩耗進行が速いことが明らかである。
上述のように、この発明の被覆超硬切削工具は、耐摩耗性被覆層を構成するＡｌ₂ Ｏ₃ 主体層のもつすぐれた耐摩耗性および密着性によって、通常の条件での各種鋼の連続切削および断続切削は勿論のこと、きわめて苛酷な切削条件である断続切削を高切り込みおよび高送りの重切削条件で行っても前記Ａｌ₂ Ｏ₃ 主体層に剥離の発生なく、かつ切刃に欠けやチッピングの発生もなく、すぐれた耐摩耗性を示し、長期に亘ってすぐれた切削性能を発揮するものであり、切削加工の省エネ化および省力化に十分満足に対応できるものである。
【図面の簡単な説明】
【図１】 アークイオンプレーティング装置の概略説明図である。[0001]
BACKGROUND OF THE INVENTION
The present invention is a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide cutting tool) that has excellent wear resistance and thus exhibits excellent cutting performance over a long period of time, for example, in continuous cutting and intermittent cutting of steel. It is said).
[0002]
[Prior art]
Conventionally, in general, for example, an arc ion plating apparatus which is a kind of physical vapor deposition apparatus schematically shown in FIG. 1 is used, and an anode electrode and Ti are heated with a heater at a temperature of, for example, 700 ° C. Or, an arc discharge is generated between the cathode electrode (evaporation source) in which a Ti—Al alloy having a predetermined composition is set, and at the same time, either or both of methane gas and nitrogen gas are introduced into the apparatus as a reaction gas, On the other hand, a tool substrate (hereinafter, referred to as WC) based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) based cermet, and disposed opposite to the anode electrode and the cathode electrode with a predetermined interval. These are collectively referred to as a carbide tool substrate), for example, under the condition that a bias voltage of −120 V is applied. For example, as described in JP-A No. 62-56565, a Ti carbide layer, a nitride layer, and a carbonitride layer (hereinafter referred to as “the average layer thickness”) of 0.1 to 10 μm are formed on the surface of the substrate. Each having an average layer thickness of 0.5 to 15 μm through an adhesive undercoating layer composed of one single layer or two or more multilayers (shown as TiC layer, TiN layer, and TiCN layer, respectively) One single layer or two types of Ti and Al composite nitride [hereinafter referred to as (Ti, Al) N] layer and composite carbonitride [hereinafter referred to as (Ti, Al) CN] layer A coated cemented carbide cutting tool manufactured by vapor-depositing a tough coating layer composed of multiple layers is known.
[0003]
[Problems to be solved by the invention]
On the other hand, the FA and speeding-up of cutting work in recent years are remarkable, and there are many demands for labor saving and energy saving of cutting work, and accordingly, it is strongly desired to extend the service life of cutting tools. In the case of the above conventional coated carbide cutting tool, the toughness coating layer comprising the (Ti, Al) N layer and the (Ti, Al) CN layer constituting the same has excellent strength and toughness and good chipping resistance. Although it exhibits the properties (the property that micro-chips are less likely to occur in the tool cutting edge), the wear life is not sufficient, so that the service life is reached in a relatively short time.
[0004]
[Means for Solving the Problems]
Therefore, the present inventors, from the above viewpoint, as a result of conducting research to improve the wear resistance of the conventional coated carbide cutting tool,
(A) Attempts have been made to form an aluminum oxide layer as a coating layer by physical vapor deposition , and the resulting aluminum oxide layer has excellent heat resistance and high hardness, thus improving wear resistance. The aluminum oxide layer is a toughness coating layer that constitutes the above-mentioned conventional coated carbide cutting tool, and is in close contact with the (Ti, Al) N layer and the (Ti, Al) CN layer. Therefore, in the coated carbide cutting tool in which the aluminum oxide layer is formed on the surface of the conventional coated carbide cutting tool, the cutting of the tool cutting blade with high load is particularly high. When the cutting is performed under heavy cutting conditions such as high feed, the aluminum oxide layer is easily peeled off and cannot be put to practical use.
[0005]
(B) The aluminum oxide layer is formed on the surface of the (Ti, Al) N layer and (Ti, Al) CN layer constituting the toughness coating layer of the above conventional coated carbide cutting tool by an arc ion plating apparatus. At the time of formation, this is specified as an arc ion plating method which is one of physical vapor deposition methods , and Ti, Zr, and Hf having an ion radius significantly larger than Al, that is, Al having an ion radius of 0.57 angstroms. One or more of Ti having an ionic radius of 0.76 angstroms, 0.87 angstroms of Zr, and 0.84 angstroms of Hf, and Al atoms in the crystal structure of Al ₂ O _3. A part of is replaced with 0.01 to 10 atomic%, preferably 0.02 to 5 atomic% in the total amount with Al. When an Al ₂ O ₃ based layer comprising a solid solution containing in the form, Al ₂ O ₃ based layer will always have the have the crystal structure of Al ₂ O ₃ of this result, at same arc ion plating apparatus The formed Al ₂ O ₃ layer, that is, the Al ₂ O ₃ layer having a crystal structure of Al ₂ O ₃ , which does not contain a part of Ti, Zr, and Hf , is also affected by the layer thickness. Has a compressive residual stress of 1.2 to 3 GPa due to a significant increase in strain in the lattice due to a large ion radius difference, The Al ₂ O ₃ main layer having a very high compressive residual stress adheres to the (Ti, Al) N layer and (Ti, Al) CN layer extremely strongly and retains the characteristics of Al ₂ O ₃ as it is. From (Ti, Al) N The coated carbide cutting tool in which the Al ₂ O ₃ main layer is further formed on the surface of the layer and the (Ti, Al) CN layer by an arc ion plating apparatus is used, for example, for intermittent cutting of steel, particularly for tool cutting. Even when the cutting is performed under heavy cutting conditions such as high cutting and high feed that require a high load on the blade, the Al ₂ O ₃ main layer does not peel and exhibits excellent wear resistance over a long period of time.
The research results shown in (a) and (b) above were obtained.
[0006]
This invention was made based on the above research results,
(A) In an arc ion plating apparatus, Ti is used as the cathode electrode (evaporation source) on the surface of the carbide tool base, and either or both of methane gas and nitrogen gas are introduced as the reaction gas. An adhesive base coating layer comprising one single layer or two or more multilayers of the formed TiC layer, TiN layer, and TiCN layer, and having an average layer thickness of 0.1 to 10 μm is deposited. ,
(B) In the same arc ion plating apparatus, Ti—Al alloy is used as the cathode electrode (evaporation source) on the surface of the adhesive base coating layer, and nitrogen gas or nitrogen gas and methane gas are introduced as the reaction gas. Toughness having an average layer thickness of 0.5 to 15 μm consisting of one single layer or two types of multilayers of (Ti, Al) N layer and (Ti, Al) CN layer formed Vapor-depositable coating layer,
(C) Further, in an arc ion plating apparatus, Al- (containing one or more of Ti, Zr, and Hf as a cathode electrode (evaporation source) on the surface of the toughness coating layer. (Ti, Zr, Hf) alloy, a ratio of a part of Al to the total amount of Al while maintaining the crystal structure of Al ₂ O ₃ formed by introducing oxygen gas as a reaction gas And an Al ₂ O ₃ main layer having a high compressive residual stress , containing 0.02 to 5 atomic% of Ti, Zr, and Hf in one or more of substitutional solid solution, This is characterized by a coated carbide cutting tool with excellent wear resistance, which is formed by vapor-depositing a wear-resistant coating layer having an average layer thickness of 0.5 to 15 μm.
[0007]
The reason why the average layer thicknesses of the adhesive base coating layer, the toughness coating layer, and the wear-resistant coating layer are limited as described above in the coated carbide cutting tool of the present invention will be described.
(A) Adhesive undercoating layer When the average layer thickness is less than 0.1 μm, it is not possible to ensure strong adhesion between the cemented carbide tool substrate and the tough coating layer, while the average layer thickness is 10 μm. If it exceeds, thermoplastic deformation will occur due to high heat generated during cutting, uneven wear will occur in the cutting edge, this will cause the wear progress to be rapidly accelerated, so the average layer thickness is 0.1 to It was determined to be 10 μm.
[0008]
(B) Toughness coating layer If the average layer thickness is less than 0.5 μm, the desired excellent toughness cannot be exhibited, and as a result, chipping and chipping (minute chipping) are likely to occur on the cutting edge. When the average layer thickness exceeds 15 μm, as in the case of the adhesive base coating layer, thermoplastic deformation occurs due to high heat generated during cutting, and uneven wear occurs at the cutting edge, which rapidly accelerates the progress of wear. Therefore, the average layer thickness was set to 0.5 to 15 μm.
[0009]
(C) Abrasion-resistant coating layer (Al ₂ O ₃ main layer)
If the average layer thickness is less than 0.5 μm, the desired excellent wear resistance cannot be ensured. On the other hand, if the average layer thickness exceeds 15 μm, the cutting edge tends to be chipped or chipped. The average layer thickness was set to 0.5 to 15 μm.
[0010]
The above-mentioned Al in wear-resistant coating layer Ti, Zr, and was set to 0.02 to 5 atomic% substitution content by Hf, the content is the wear-resistant coating is less than 0.02 atomic% In some cases, a compressive residual stress that can ensure sufficient adhesion between the layer and the toughness coating layer cannot be formed . On the other hand, if the content exceeds 5 atomic%, the compressive residual stress increases. This is based on the reason that self-destruction may occur depending on cutting conditions .
Further, a TiN layer having an average layer thickness of 0.1 to 2 μm may be formed on the wear-resistant coating layer as necessary. This is because the TiN layer has a golden color tone. In this case, if the layer thickness is less than 0.1 μm, the application of the color tone is insufficient, whereas the application of the color tone is up to 2 μm. An average layer thickness is sufficient.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, the coated carbide cutting tool of the present invention will be specifically described with reference to examples.
As raw material powders, WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr _{3 each} having an average particle diameter of 1 to 3 μm. C ₂ powder, TiN powder, TaN powder, and Co powder were prepared, and these raw material powders were blended in the blending composition shown in Table 1, wet-mixed by a ball mill for 72 hours, dried, and then 1.5 × 10 ^The green compact was press-molded at a pressure of ⁸ Pa, and the green compact was sintered in vacuum at a temperature of 1400 ° C. for 1 hour. After sintering, the cutting edge portion had an R of 0.05 Honing was performed to form cemented carbide tool bases A-1, A-3, 4, and A-6 to 8 made of a WC-based cemented carbide having an ISO standard / SPGA120408 chip shape.
[0012]
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 powder, all 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 at a pressure of 9.8 × 10 ⁷ Pa. The green compact is press-molded, and the green compact is sintered in a nitrogen atmosphere of 1.3 × 10 ³ Pa at a temperature of 1540 ° C. for 1 hour. After sintering, the cutting edge portion has R = 0. 0.03 honing was performed to form carbide tool bases B-2 and B-4 , 5 made of TiCN-based cermet having ISO standard / CNMG120406 chip shape.
[0013]
Then, these carbide tool substrates A-1, A-3, 4, and A-6 to 8, and B-2 and B-4 , 5 were ultrasonically cleaned in acetone and dried. Each is loaded into the arc ion plating apparatus shown in FIG. 1, and as the cathode electrode (evaporation source), Ti is used for forming an adhesive base coating layer, and various component compositions are used for forming a tough coating layer. Each Ti-Al alloy was installed, and the inside of the apparatus was evacuated and kept at a vacuum of 1.3 × 10 ⁻³ Pa, while the inside of the apparatus was heated to 500 ° C. with a heater, and then Ar gas was introduced into the apparatus In this state, a pulse bias voltage of −800 V is applied to the carbide tool substrate to clean the surface of the carbide tool substrate with Ar gas bombardment, and then methane gas and nitrogen as reaction gases in the apparatus. Any of gas Or, both are introduced to make a reaction atmosphere of 2.5 Pa, the pulse bias voltage applied to the cemented carbide tool base is lowered to −200 V, and arc discharge is generated between the cathode electrode and the anode electrode, Thus, the conventional coated carbide is formed by forming the adhesive base coating layer and the tough coating layer having the target composition and target layer thickness shown in Table 3 on the surfaces of the carbide tool bases A1 to A8 and B1 to B6. Cutting tools 1 to 13 were produced, respectively.
[0014]
Then, on each surface of these conventional coated carbide cutting tools 1 to 13 , one of Ti, Zr, and Hf as a cathode electrode (evaporation source) or the same as the arc ion plating apparatus of FIG. 1 or An Al— (Ti, Zr, Hf) alloy containing two or more kinds in a predetermined amount is mounted, the inside of the apparatus is evacuated and kept in a vacuum of 1.3 × 10 ⁻³ Pa, and the inside of the apparatus is set to 620 to 200 with a heater. While being heated to a predetermined temperature within the range of 720 ° C., the pulse bias voltage applied to the carbide tool substrate is set to −700 V, and oxygen gas is introduced into the apparatus as a reaction gas while the cathode electrode and the anode electrode arc discharge is generated, with the present invention coated cemented carbide cutting tool by forming the wear-resistant coating layer of Al ₂ O ₃ main layers of the target composition and target layer thicknesses shown in Table 4 between the To 13 were prepared, respectively.
Quantitative analysis of Ti, Zr, and Hf contents in the Al ₂ O ₃ main layer constituting the wear-resistant coating layer of the above coated carbide cutting tools 1 to 13 of the present invention using an energy dispersive X-ray measuring apparatus. As a result, it showed substantially the same content as the target content of Tables 5 and 6, and the compressive residual stress of the Al ₂ O ₃ main layer was measured using an X-ray stress measurement method. The result shown in 6 was shown. Furthermore, the composition and layer thickness of various coating layers were also measured by Auger spectroscopy and an optical microscope. As a result, the compositions and average layer thicknesses substantially the same as the target compositions and target layer thicknesses in Tables 3 to 6 (arbitrary 5 locations Average value).
[0015]
Next, among the various coated carbide cutting tools obtained as a result, the present coated carbide cutting tools 1 to 10 and the conventional coated carbide cutting tools 1 to 10 ,
Work material: JIS · S45C lengthwise equal 4 round grooved round bars,
Cutting speed: 320 m / min.,
Feed: 0.3mm / rev.,
Cutting depth: 3.2 mm,
Cutting time: 10 minutes,
Carbon steel dry interrupted high depth cutting test under the following conditions, and
Work material: JIS / SNCM440 lengthwise equidistant 4 round bars with vertical grooves,
Cutting speed: 280 m / min.
Feed: 0.45mm / rev.,
Cutting depth: 1.5mm,
Cutting time: 10 minutes,
The dry interrupted high feed cutting test of the alloy steel under the conditions of the present invention is performed, and the coated carbide cutting tools 11 to 13 and the conventional coated carbide cutting tools 11 to 13 of the present invention are as follows.
Work material: JIS / SUS304 lengthwise equidistant four round grooved round bars,
Cutting speed: 280 m / min.
Feed: 0.3mm / rev.,
Cutting depth: 3.2 mm,
Cutting time: 10 minutes,
Stainless steel dry interrupted high-cut feed cutting test under the conditions of
Work material: JIS / SNCM439 round direction bar with four equal intervals in the length direction,
Cutting speed: 320 m / min.,
Feed: 0.45mm / rev.,
Cutting depth: 1.5mm,
Cutting time: 10 minutes,
A dry intermittent high feed cutting test was performed on the alloy steel under the above conditions, and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 5 .
[0016]
[Table 1]

[0017]
[Table 2]

[0018]
[Table 3]

[0019]
[Table 4]

[0020]
[Table 5]

[0021]
【The invention's effect】
From the results shown in Tables 3 to 5 , the coated carbide cutting tools 1 to 13 of the present invention are all Ti _{2 in} which the Al ₂ O ₃ main layer constituting the wear-resistant coating layer has a remarkably large ionic radius compared to Al. , Zr, and Hf are substituted and contained so that a remarkably high compressive residual stress is maintained, and the (Ti, Al) N layer and (Ti, Al) constituting the toughness coating layer are formed. ) Since the steel layer comes into close contact with the CN layer, even when intermittent cutting of steel is performed under high cutting and high feed heavy cutting conditions, the Al ₂ O ₃ main layer does not peel and has excellent wear resistance. In contrast, the conventional coated carbide cutting tools 1 to 13 exhibit rapid wear, and the progress of wear is fast under the above severe conditions due to the lack of wear resistance of the tough coating layer. It is clear.
As described above, the coated cemented carbide cutting tool of the present invention has a continuous wear of various steels under normal conditions due to the excellent wear resistance and adhesion of the Al ₂ O ₃ main layer constituting the wear resistant coating layer. Not only the cutting and interrupted cutting, but also the severe cutting conditions of interrupted cutting under high cutting and high feed heavy cutting conditions, the Al ₂ O ₃ main layer does not peel and the cutting edge is chipped. No chipping or chipping, excellent wear resistance, excellent cutting performance over a long period of time, and fully satisfactory for energy saving and labor saving in cutting.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of an arc ion plating apparatus.

Claims (1)

(A) In an arc ion plating apparatus, Ti is used as a cathode electrode (evaporation source) on the surface of a tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet, and methane gas and nitrogen as reaction gases A single layer or two or more layers of a carbide layer, nitride layer, and carbonitride layer of Ti formed by introducing one or both of gases; and depositing the adhesion underlayer coating layer having an average layer thickness of 0.1 to 10 [mu] m,
(B) In the same arc ion plating apparatus, Ti—Al alloy is used as the cathode electrode (evaporation source) on the surface of the adhesive base coating layer, and nitrogen gas or nitrogen gas and methane gas are introduced as the reaction gas. Toughness having an average layer thickness of 0.5 to 15 μm, consisting of one single layer or two types of multilayers of Ti and Al composite nitride layer and composite carbonitride layer formed Deposit a coating layer,
(C) Further, in an arc ion plating apparatus, Al- (containing one or more of Ti, Zr, and Hf as a cathode electrode (evaporation source) on the surface of the toughness coating layer. (Ti, Zr, Hf) alloy, which is formed by introducing oxygen gas as a reaction gas, while maintaining the crystal structure of Al ₂ O ₃ , and a ratio of a part of Al to the total amount of Al And an Al ₂ O ₃ main layer having a high compressive residual stress , containing 0.02 to 5 atomic% of Ti, Zr, and Hf in one or more of substitutional solid solution, A surface-coated cemented carbide cutting tool having excellent wear resistance, which is formed by vapor-depositing a wear-resistant coating layer having an average layer thickness of 0.5 to 15 µm.

Images