JP2004195564A - Surface-covered cutting tool and throw-away tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long service life cutting tool for enhancing adhesion of a hard covering layer without causing separation between a TiCN layer and an Al<SB>2</SB>O<SB>3</SB>layer and having superior chipping resistance and abrasion resistance particularly under a severe cutting condition of applying a strong shock to a tool cutting edge such as intermittent cutting of cast iron. <P>SOLUTION: This surface-covered cutting tool 1 having the hard covering layer 3 is manufactured by successively laminating a TiCN layer 5 composed of a striped crystal vertical to the thickness direction a TiCN layer 6-a TiCNO layer 7-an Al<SB>2</SB>O<SB>3</SB>layer 8 composed of a granular crystal on a surface of a hard alloy 2 composed of a hard phase composed of carbide, nitride and carbonitride selected from a group of metals of periodic table No. 4a, 5a and 6a group and a binding phase composed of at least one kind of iron group metal. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３０】
【表２】

【００３１】
そして、この切削工具を用いて下記の条件によりダクタイル鋳鉄の切削を２５分間行い、切削工具の切刃の観察を行うとともにフランク摩耗量および先端摩耗量を測定した。さらに、溝付き鋼材により断続試験を行い、欠損したときの衝撃回数を比較した。結果は表３に示した。
【００３２】
（摩耗試験）
被削材 ：ダクタイル鋳鉄（ＦＣＤ４５０）
工具形状：ＣＮＭＡ１２０４１２
切削速度：３５０ｍ／分
送り速度：０．４ｍｍ／ｒｅｖ
切り込み：２ｍｍ
その他 ：水溶性切削液使用
（断続試験）
被削材 ：ダクタイル鋳鉄（ＦＣＤ７００）
工具形状：ＣＮＭＡ１２０４１２
切削速度：３００ｍ／分
送り速度：０．４ｍｍ／ｒｅｖ
切り込み：１．５ｍｍ
その他 ：水溶性切削液使用
【００３３】
【表３】

【００３４】
表２、３の結果より、（ＴｉＮ層−）粒状ＴｉＣＮ層（ＴｉＣＮ＜ｐ＞）−筋状ＴｉＣＮ層（ＴｉＣＮ＜ｃ＞）−ＴｉＣＯ層−Ａｌ₂Ｏ₃層の構成からなる試料Ｎｏ．１では、切刃部の硬質被覆層のうち筋状ＴｉＣＮ層とＴｉＣＯ層との間で層剥離が発生して切削性能が低下した。また、（ＴｉＮ層−）筋状ＴｉＣＮ層−ＴｉＣＮＯ層−Ａｌ₂Ｏ₃層（−ＴｉＮ層）の構成からなる試料Ｎｏ．６では、切刃部の硬質被覆層のうち筋状ＴｉＣＮ層とＴｉＣＮＯ層との間で層剥離が発生して切削性能が低下した。
【００３５】
これに対して、本発明に従い、硬質被覆層を、（ＴｉＮ層−）筋状ＴｉＣＮ層−粒状晶のＴｉＣＮ層−ＴｉＣＮＯ層−Ａｌ₂Ｏ₃層（−ＴｉＮ層）の構成とした試料Ｎｏ．２〜５では、いずれも硬質被覆層の剥離が発生せず優れた切削性能を有するものであった。
【００３６】
【発明の効果】
以上詳述したとおり、本発明の表面被覆切削工具によれば、筋状ＴｉＣＮ層、粒状晶のＴｉＣＮ層、ＴｉＣＮＯ層、Ａｌ₂Ｏ₃層の順に積層した構成の硬質被覆層を具備することによって、特に鋳鉄の切削等の工具切刃に強い衝撃がかかるような過酷な切削条件においても、ＴｉＣＮ層とＡｌ₂Ｏ₃層との間で剥離が発生することなく硬質被覆層の強固な密着性を維持できることから優れた耐摩耗性および耐欠損性を有する切削工具が得られる。
【００３７】
また、本発明のスローアウェイチップによれば、両主面の周縁部に設けられたランド面と該ランド面から内側にブレーカ部をはさんで設けられた中央面とを同じ高さにすることに加え、筋状ＴｉＣＮ層、粒状晶のＴｉＣＮ層、ＴｉＣＮＯ層、Ａｌ₂Ｏ₃層の順に積層した構成の硬質被覆層を具備することによって、チップのすわりの安定性が高くなり加工時にチップ自体が微振動して硬質被覆層がより強い衝撃を受けて硬質被覆層が剥離することを防止できるとともに、硬質被覆層自体もＴｉＣＮ層とＡｌ₂Ｏ₃層との間で剥離が発生することなく硬質被覆層の強固な密着性を維持できることから優れた耐摩耗性および耐欠損性が得られる。
【図面の簡単な説明】
【図１】本発明の表面被覆切削工具の概略断面図である。
【図２】図１の表面被覆切削工具の一例であるスローアウェイチップの好適な形状を説明するための概略断面図である。
【符号の説明】
１ 表面被覆切削工具
２ 母材
３ 硬質被覆層
５ 厚み方向に垂直な筋状結晶からなるＴｉＣＮ層（筋状ＴｉＣＮ層）
６ 粒状結晶からなるＴｉＣＮ層（粒状ＴｉＣＮ層）
７ ＴｉＣＮＯ層
８ Ａｌ₂Ｏ₃層
１０ ＡｌＯＮ層
１１ 下層（硬質被覆層の最内層をなすＴｉＮ層）
１２ 上層（硬質被覆層の最外層をなすＴｉＮ層）
２１ すくい面（着座面）
２２ 着座面（すくい面）
２３ 逃げ面
２４ 切刃
２５ ランド面
２６ ブレーカ部
２７ 中央面（すわり面）
２８ クランプ穴
２９ ホーニングＲ部
３０ 微小研磨部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to surface-coated cutting tools and indexable inserts formed by applying a plurality of hard coating layers having excellent chipping resistance and abrasion resistance to the surface, particularly carbon steel, not only steel such as alloy steel, The present invention relates to a surface-coated cutting tool and a throw-away insert having excellent fracture resistance and cutting characteristics even in cutting in which a large impact such as intermittent cutting of cast iron is applied to a cutting edge.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a cutting tool that has been widely used for metal cutting includes at least one of metals of Group 4a, 5a, and 6a of the periodic table, particularly a hard phase mainly composed of WC (tungsten carbide) and Co (cobalt). A hard coating layer such as a TiC layer, a TiN layer, a TiCN layer, and an Al ₂ O ₃ layer is formed on the surface of a hard alloy such as a cemented carbide or a cermet made of a binder phase of an iron group metal such as Ni or nickel (nickel). Alternatively, a surface-coated cutting tool formed by applying a plurality of layers is often used.
[0003]
The above-mentioned hard coating layer is described in Patent Document 1 described below, in which (granular TiCN layer) -columnar TiCN layer-granular TiCN layer-TiCO layer-Al ₂ O ₃ layer is laminated in this order (No. 1 in Table 3). , TiCN layer of granular - that are sequentially stacked columnar TiCN layer -TiCNO layer -Al ₂ O ₃ layer (No.6 in Table 3) are described, chipping resistance of the tool have been described to be improved.
[0004]
[Patent Document 1]
JP-A-6-8008 [0005]
[Problems to be solved by the invention]
However, the chipping resistance is insufficient even with the layer configuration described in Patent Document 1, and in particular, when interrupted cutting of cast iron is performed, peeling of the hard coating layer occurs from the TiCN layer to the Al ₂ O ₃ layer. There was a problem that it was easy.
[0006]
Accordingly, the present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a TiCN layer and an Al layer even under severe cutting conditions in which a strong impact is applied to a tool cutting edge such as intermittent cutting of cast iron. It is an object of the present invention to provide a long-life cutting tool that can enhance the adhesion of a hard coating layer without occurrence of separation from a ₂ O ₃ layer and has excellent fracture resistance and wear resistance.
[0007]
[Means for Solving the Problems]
The present inventor has studied a method for improving the fracture resistance of the tool with respect to the above-described problem. As a result, the hard coating layer is formed as a TiCN layer composed of streak crystals perpendicular to the thickness direction-a TiCN layer composed of granular crystals-a TiCNO layer. by formed by the lamination in the order of -al ₂ O ₃ layer, in particular even in severe cutting conditions such as a strong impact according to the tool cutting edge interrupted cutting such cast iron, the TiCN layer and the Al ₂ O ₃ layer It has been found that a cutting tool having excellent abrasion resistance and chipping resistance can be obtained because strong adhesion of the hard coating layer can be maintained without occurrence of separation between the hard coating layers.
[0008]
That is, the surface-coated cutting tool of the present invention comprises a hard phase composed of carbide, nitride and carbonitride selected from the group consisting of metals of groups 4a, 5a and 6a of the periodic table, and a bond composed of at least one kind of iron group metal. A hard coating layer formed by sequentially laminating a TiCN layer composed of streak crystals perpendicular to the thickness direction, a TiCN layer composed of granular crystals, a TiCNO layer, and an Al ₂ O ₃ layer on the surface of the hard alloy composed of the phases. It is characterized by doing.
[0009]
Here, it is desirable that an AlON layer is interposed between the TiCNO layer and the Al ₂ O ₃ layer.
[0010]
Further, the throw-away insert of the present invention has a configuration of a surface-coated cutting tool having a hard coating layer on the surface of the hard alloy as described above, and the two main surfaces that are substantially flat and have a polygonal shape are rake faces. A seating surface, a side surface forming a flank surface, a double-sided usable throwaway tip having a cutting edge at an intersection ridge line between the both main surfaces and the flank surface, and a land surface at a peripheral portion of the both main surfaces. A central surface (sitting surface) is provided between the land surface and the breaker portion, and the central surface and the land surface are at the same height.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The surface-coated cutting tool and the indexable insert of the present invention will be described with reference to FIG. 1 which is a schematic view of one example.
[0012]
According to FIG. 1, the surface-coated cutting tool 1 is made of tungsten carbide (WC) and, if desired, at least one selected from the group consisting of carbides, nitrides and carbonitrides of metals of Groups 4a, 5a and 6a of the periodic table. Alloy composed of a hard phase composed of a hard phase composed of a ferrous metal such as cobalt (Co) and / or nickel (Ni), or a titanium carbide (TiC) or a titanium carbonitride (TiCN). A hard phase comprising at least one selected from the group consisting of carbides, nitrides, and carbonitrides of metals belonging to Groups 4a, 5a, and 6a of the Ritsumeikan Table, comprising a ferrous metal such as cobalt (Co) and / or nickel (Ni); A plurality of hard coating layers 3 are formed on a surface of a base material 2 having a predetermined shape made of a hard alloy such as a cermet and joined in a phase.
[0013]
According to the present invention, as shown in FIG. 1, the hard coating layer 3 is composed of a TiCN layer made of a streak crystal perpendicular to the thickness direction (hereinafter, simply referred to as a streak TiCN layer) 5-TiCN made of a granular crystal. A major feature is that layers (hereinafter simply abbreviated as granular TiCN layers) 6-TiCNO layer 7-Al ₂ O ₃ layer 8 are successively laminated, and this makes it possible to cut cast iron, especially intermittent cutting of cast iron. Even under severe cutting conditions in which a strong impact is applied to a tool cutting edge such as the above, strong adhesion of the hard coating layer can be maintained without peeling between the TiCN layer 5 and the Al ₂ O ₃ layer 8. Thus, the cutting tool 1 having excellent wear resistance and fracture resistance is obtained.
[0014]
That is, as the configuration of the hard coating layer 3, the toughness of the hard coating layer 3 is increased by providing the striped TiCN layer 5, and the wear resistance of the hard coating layer 3 is increased by providing the Al ₂ O ₃ layer 8. In addition, the granular TiCN layer 6 and the TiCNO layer 7 are sequentially interposed between the striped TiCN layer 5 and the Al ₂ O ₃ layer 8 so that the striped TiCN layer 5 and the Al ₂ O ₃ layer 8 are interposed. It is possible to prevent the hard coating layer 3 from peeling off, which is liable to occur.
[0015]
According to the present invention, the AlON layer 10 is interposed between the above-described TiCNO layer 7 and the Al ₂ O ₃ layer 8 so that the streaky TiCN layer-granular TiCN layer-TiCNO layer-AlON layer-Al ₂ O the _three-layer structure that is desirable in terms of enhancing the adhesion between the TiCN layer and the Al ₂ O ₃ layer.
[0016]
Furthermore, according to the present invention, streaky TiCN layer described above - granular TiCN layer -TiCNO layer - (AlON layer) -Al ₂ O ₃ layer from the base material between the hard layer and the base material into the coating layer of the The diffusion of carbon, that is, decarburization is prevented, and the embrittlement phase on the base material surface, the so-called? In order to suppress the formation of a phase, at least one layer selected from the group consisting of a TiN layer, a TiCN layer, a TiCO layer, a TiCNO layer, a TiNO layer, and a TiC layer may be interposed as the lower layer 11. In order to improve the welding resistance to the work material at the time of cutting on the surface of the steel and to clarify the use corner, the upper layer 12 is made of a TiN layer, a TiCN layer, a TiCO layer, a TiCNO layer, a TiNO layer, and a TiC layer. At least one layer selected from layers may be laminated.
[0017]
In addition, the thickness of each layer of the hard coating layer 3 is set to be streaky TiCN layer 5: 2 to 12 m-granular TiCN layer 6: 0.0 to improve chipping resistance and wear resistance of the hard coating layer 3. 5 to 2.5 o m-TiCNO layer 7: 0.1 to 1.5 o m-AlON layer 10: 0.1 to 1.5 o m-Al ₂ O ₃ layer 8: is a 2-7 o m It is desirable.
[0018]
Further, according to the present invention, as the cutting tool, the two main surfaces 21 and 22 having a substantially flat plate shape as shown in FIG. 2 and having a polygonal shape form the rake face 21 and the seating face 22, and the side face forms the flank face 23. None, in the case of using a double-sided insertable insert 20 having a cutting edge 24 at the intersection ridge line between the main surfaces 21 and 22 and the flank 23, in order to realize excellent chipping resistance especially in cutting cast iron. 2, that is, a center surface (seat surface) 27 is provided with the land surface 25 on the peripheral edge of the two main surfaces 21 and 22 and the breaker portion 26 on the inner side of the land surface 25. It is desirable that the center surface 27 and the land surface 25 have the same height, and this increases the stability of the chip. Therefore, the chip itself vibrates slightly during processing, and the hard coating layer 3 receives a harder impact and becomes harder. Coating layer There can be prevented delamination. According to FIG. 2, a clamp hole 28 for clamping the throw-away tip 20 to a tip holder (not shown) is provided at the center of the throw-away tip 20, but the present invention is not limited to this. Instead, the chip 20 may be fixed by a clamp-on method without providing the clamp hole 28.
[0019]
In this case, in order to increase the chipping resistance of the hard coating layer 3, as shown in FIG. 1, an R honing 29 is provided on the cutting edge 24, and the surface of the hard coating layer 3 of the R honing portion 29 is finely polished. It is desirable to reduce the residual stress inherent in the hard coating layer 3 (the minute polishing portion 30).
[0020]
(Production method)
Further, in order to manufacture the surface-coated cutting tool described above, first, a metal powder, a carbon powder, and the like are added to inorganic powders such as metal carbide, nitride, carbonitride, and oxide that can be formed by firing the above-described hard alloy. Are appropriately added and mixed, and molded into a predetermined tool shape by a known molding method such as press molding, cast molding, extrusion molding, cold isostatic pressing, and then fired in a vacuum or in a non-oxidizing atmosphere. Thus, the above-described hard alloy base material 2 is manufactured.
[0021]
After the base material 2 is polished as required, a hard coating layer 3 is formed on the surface by a chemical vapor deposition method. The film forming conditions of each layer are, for example, as a reaction gas composition, 0.1 to 10 vol% of TiCl ₄ gas, 0 to 60 vol% of N ₂ gas, 0 to 0.1 vol% of CH ₄ gas, and CH ₃ in volume%. A mixed gas consisting of CN gas of 0 to 0.1 vol% and the remainder of H ₂ gas is sequentially adjusted and introduced into the reaction chamber, and 800 to 1100? , 5 to 85 kPa to form at least one streaky TiCN layer.
[0022]
The deposition conditions of the granular TiCN layer are as follows: 0.1 to 10 vol% of TiCl ₄ gas, 0 to 60 vol% of N ₂ gas, 0.1 to 10 vol% of CH ₄ gas, and H ₂ gas as the reaction gas composition. , And sequentially introduced into the reaction chamber. , 5 to 85 kPa to form a granular TiCN layer.
[0023]
Conditions for forming the TiCNO layer, 0.1~10vol% of the TiCl ₄ gas as a reaction gas composition, N ₂ gas 0~60vol%, CH ₄ gas 0.1~10vol%, CO ₂ gas 0.01 A mixed gas consisting of H ₂ gas and the remaining H ₂ gas is sequentially adjusted and introduced into the reaction chamber. , 5 to 85 kPa to form a TiCNO layer.
[0024]
The conditions for forming the AlON layer are as follows: AlCl ₃ gas at ₃ to 20 vol%, HCl gas at 0.5 to 3.5 vol%, CO ₂ gas at 0.01 to 2.5 vol%, and N ₂ gas at 0.1 to 2.5 vol%. Using a mixed gas consisting of 20 vol% and the rest of H ₂ gas, 900 to 1100? The AlON layer is coated under the conditions of 5 to 10 kPa.
[0025]
Subsequently, the AlCl ₃ gas is ₃ to 20 vol%, the HCl gas is 0.5 to 3.5 vol%, the CO ₂ gas is 0.01 to 5.0 vol%, the H ₂ S gas is 0 to 0.01 vol%, and the rest is Using a mixed gas of H ₂ gas, 900 to 1100? The Al ₂ O ₃ layer 6 is coated under the conditions of 5 to 10 kPa.
[0026]
When a lower layer is formed on the hard coating layer, for example, when a TiN layer is formed as the lower layer, 0.1 to 10 vol% of TiCl ₄ gas and 0 to 60 vol% of N ₂ gas are used as reactive gas compositions. The mixed gas consisting of H ₂ gas is adjusted sequentially and introduced into the reaction chamber. , 5 to 85 kPa. When forming the upper layer, for example, to form a TiN layer as the upper layer, the reaction gas composition is 0.1 to 10 vol% of TiCl ₄ gas, 0 to 60 vol% of N ₂ gas, and the rest is H ₂ gas. , And sequentially introduced into the reaction chamber. , 5 to 85 kPa.
[0027]
【Example】
Tungsten carbide (WC) powder having an average particle size of 1.5 m, metal cobalt (Co) powder having an average particle size of 1.2 m, and a metal element (M) shown in Table 1 having an average particle size of 2.0 m Was added and mixed at a ratio shown in Table 1, and the mixture was pressed into a cutting tool shape (CNMG120408), and then subjected to binder removal treatment. 3 or more? / Minute in a vacuum of 0.01 Pa, 1500? For 1 hour to produce a cemented carbide.
[0028]
Various hard coating layers were formed on the surface of the obtained cemented carbide by the CVD method under the conditions shown in Table 1 to produce cutting tools shown in Table 2.
[0029]
[Table 1]

[0030]
[Table 2]

[0031]
Using this cutting tool, cutting of ductile cast iron was performed for 25 minutes under the following conditions, the cutting edge of the cutting tool was observed, and the flank wear and tip wear were measured. Further, an intermittent test was performed using a grooved steel material, and the number of impacts at the time of fracture was compared. The results are shown in Table 3.
[0032]
(Wear test)
Work material: Ductile cast iron (FCD450)
Tool shape: CNMA120412
Cutting speed: 350 m / min Feeding speed: 0.4 mm / rev
Cut: 2mm
Others: Use of water-soluble cutting fluid (intermittent test)
Work material: Ductile cast iron (FCD700)
Tool shape: CNMA120412
Cutting speed: 300m / min Feeding speed: 0.4mm / rev
Cut: 1.5mm
Others: Uses water-soluble cutting fluid [0033]
[Table 3]

[0034]
From the results shown in Tables 2 and 3, from the results of Sample No. having a structure of (TiN layer-) granular TiCN layer (TiCN <p>)-streak-shaped TiCN layer (TiCN <c>)-TiCO layer-Al ₂ O ₃ layer. In No. 1, delamination occurred between the streak-like TiCN layer and the TiCO layer in the hard coating layer of the cutting edge portion, and the cutting performance was reduced. Further, (TiN layer -) samples configured in the streak TiCN layer -TiCNO layer -Al ₂ O ₃ layer (-TiN layer) No. In No. 6, in the hard coating layer of the cutting edge portion, delamination occurred between the streak-like TiCN layer and the TiCNO layer, and the cutting performance was reduced.
[0035]
In contrast, in accordance with the present invention, the hard coating layer, (TiN layer -) streaky TiCN layer - TiCN layer -TiCNO layer -Al ₂ O ₃ layer of granular crystals sample was constituted of (-TiN layer) No. In Nos. 2 to 5, the hard coating layer did not peel off and had excellent cutting performance.
[0036]
【The invention's effect】
As described above in detail, according to the surface-coated cutting tool of the present invention, by including the hard coating layer having a configuration in which the streaked TiCN layer, the granular TiCN layer, the TiCNO layer, and the Al ₂ O ₃ layer are stacked in this order. Even under severe cutting conditions such as a strong impact on the tool cutting edge such as cutting of cast iron, the strong adhesion of the hard coating layer does not occur between the TiCN layer and the Al ₂ O ₃ layer. , A cutting tool having excellent wear resistance and chipping resistance can be obtained.
[0037]
According to the indexable insert of the present invention, the land surface provided on the peripheral portion of both main surfaces and the center surface provided with the breaker portion inward from the land surface are made to have the same height. In addition to the above, by providing a hard coating layer having a configuration in which a streaked TiCN layer, a granular TiCN layer, a TiCNO layer, and an Al ₂ O ₃ layer are laminated in this order, the stability of the chip is increased, and the chip itself is processed during processing. Can prevent the hard coating layer from being peeled off due to microvibration and the hard coating layer receiving a stronger impact, and the hard coating layer itself can be prevented from peeling between the TiCN layer and the Al ₂ O ₃ layer. Since the strong adhesion of the hard coating layer can be maintained, excellent wear resistance and chipping resistance can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a surface-coated cutting tool of the present invention.
FIG. 2 is a schematic cross-sectional view for explaining a preferred shape of a throw-away insert which is an example of the surface-coated cutting tool of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Surface-coated cutting tool 2 Base material 3 Hard coating layer 5 TiCN layer (striped TiCN layer) composed of streak crystals perpendicular to the thickness direction
6 TiCN layer composed of granular crystals (granular TiCN layer)
7 TiCNO layer 8 Al ₂ O ₃ layer 10 AlON layer 11 Lower layer (TiN layer as innermost layer of hard coating layer)
12 Upper layer (TiN layer which is the outermost layer of the hard coating layer)
21 Rake surface (seating surface)
22 Seating surface (rake face)
23 Flank 24 Cutting edge 25 Land 26 Breaker 27 Central surface (Seat surface)
28 Clamp hole 29 Honing R part 30 Fine polishing part

Claims (3)

On the surface of a hard alloy composed of a hard phase composed of carbide, nitride and carbonitride selected from the group of metals of Groups 4a, 5a and 6a of the periodic table and a binder phase composed of at least one type of iron group metal A surface-coated cutting tool comprising a hard coating layer formed by sequentially laminating a TiCN layer composed of streak crystals perpendicular to the thickness direction, a TiCN layer composed of granular crystals, a TiCNO layer, and an Al ₂ O ₃ layer. . Surface-coated cutting tool according to claim 1, characterized by being interposed AlON layer between the TiCNO layer and the Al ₂ O ₃ layer. A two-sided throw that has a substantially flat plate-like shape and two polygonal main surfaces forming a rake surface and a seating surface, a side surface forming a flank surface, and having a cutting edge at an intersection ridge line between the both main surfaces and the flank surface. An away tip, wherein the throw away tip has a configuration of a surface-coated cutting tool having a hard coating layer on the surface of the hard alloy according to claim 1 or 2, and a land surface on a peripheral portion of the two main surfaces, A throw-away chip, wherein a center surface is provided between the land surface and a breaker portion, and the center surface and the land surface are at the same height.

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