JP5109202B2 - Surface coated cutting tool - Google Patents

Description

  The present invention relates to a surface-coated cutting tool in which a coating layer is formed on a substrate made of a cemented carbide.

  Conventionally, it has been demanded to improve the life of surface-coated cutting tools, and as one of countermeasures there have been proposed many attempts to improve the adhesion between a base material such as cemented carbide and a coating layer.

  For example, in Patent Document 1 and Patent Document 2, it is proposed to improve the adhesion between the substrate and the coating layer by diffusing components such as Co constituting the substrate into the coating layer. However, when the component of the base material diffuses into the coating layer in this way, or when the component of the base material reacts with the gas component for forming the coating layer, it is called the η layer on the outermost surface of the base material. An ultrathin layer is formed, or a diffusion layer made of a base material component is formed in the interface region between the base material and the coating layer. And when such an ultra-thin layer or diffusion layer is formed, the phenomenon that the base material becomes brittle in the vicinity region thereof, thereby causing a problem that the adhesion between the base material and the coating layer decreases. was there.

On the other hand, Patent Document 3 proposes that the lowermost layer of the coating layer in contact with the substrate is composed of an intermetallic compound of Co in order to improve the adhesion between the substrate and the coating layer. Although it is possible to improve the adhesion between the base material and the coating layer to some extent by this proposal, in recent cutting technology, extremely high performance is required for the surface-coated cutting tool. It is required to improve the tool life by further improving the adhesion between the coating layer and the coating layer.
JP 09-262705 A JP 2000-355777 A Japanese Patent Laid-Open No. 07-237011

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a surface-coated cutting tool having improved adhesion between a substrate and a coating layer.

The surface-coated cutting tool of the present invention comprises a substrate made of a cemented carbide and one or more coating layers covering the substrate, and the lowest layer in contact with the substrate among the coating layers is Co and it consists of a chlorine and unavoidable impurities, wherein the thickness is 0.1μm or less than 0.005 .mu.m.

  Here, the lowermost layer preferably further contains at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron.

  Further, the coating layer includes one or more hard layers formed on the lowermost layer, and the hard layers are composed of IVa group element, Va group element, VIa group element, Al, and Si in the periodic table. It is preferably composed of a compound consisting of at least one element selected from the group consisting of and at least one element selected from the group consisting of carbon, nitrogen, oxygen, boron, and chlorine, and Ti, Zr, And at least one element selected from the group consisting of Hf and at least one element selected from the group consisting of carbon, nitrogen, oxygen, boron, and chlorine.

  The hard layer preferably includes a layer mainly composed of TiCN formed by a chemical vapor deposition method, and preferably includes a layer including α-alumina or κ-alumina. The lowermost layer preferably has a ratio of Cl atomic% to Co atomic% of 0.01 to 1.5.

  In addition, a composition gradient layer is formed between the lowermost layer and the hard layer, and the composition gradient layer is a layer whose composition changes in the thickness direction from the composition of the lowermost layer to the composition of the hard layer. It is preferable that

  The base material is a cemented carbide containing tungsten carbide, an iron-based metal, and a third component, and the third component is a group IVa element, a group Va element, a group VIa element, an Al element in the periodic table. And a compound consisting of at least one element selected from the group consisting of Si and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron, and / or group IVa element of the periodic table , Va group element, VIa group element, Al, and Si are preferably at least one element selected from the group consisting of Si and Si.

The present invention also relates to a method for producing a surface-coated cutting tool comprising a substrate made of a cemented carbide and one or more coating layers covering the substrate, the step of preparing the substrate, and the coating layer The lowermost layer in contact with the substrate includes a step of forming a lowermost layer made of Co, chlorine and inevitable impurities and having a thickness of 0.005 μm to 0.1 μm.

  Since the surface-coated cutting tool of the present invention has the above-described configuration, the adhesion between the base material and the coating layer is dramatically improved.

Hereinafter, the present invention will be described in more detail.
<Surface coated cutting tool>
The surface-coated cutting tool of the present invention comprises a substrate made of a cemented carbide and one or more coating layers that coat the substrate. The surface-coated cutting tool of the present invention having such a configuration is, for example, a drill, an end mill, a milling edge-changing cutting tip, a turning edge-changing cutting tip, a metal saw, a gear cutting tool, a reamer, a tap, or a crank. It is extremely useful as a cutting edge exchangeable cutting tip for shaft pin milling.

<Base material>
The base material of the present invention is made of a cemented carbide. As such a cemented carbide, a conventionally known one used as a base material for this type of surface-coated cutting tool can be used without any particular limitation. For example, a WC-based cemented carbide containing WC and Co as main components can be cited as such a cemented carbide. Such a WC-based cemented carbide can further include carbides such as Ti, Ta, Nb, V, Cr, and Zr, nitrides, carbonitrides, and the like.

  Such a substrate of the present invention is a cemented carbide containing tungsten carbide, an iron-based metal, and a third component in particular, and the third component is a group IVa element or a group Va element in the periodic table. A compound comprising at least one element selected from the group consisting of Group VIa elements, Al and Si, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron, and / or a period It is preferably at least one element selected from the group consisting of IVa group elements, Va group elements, VIa group elements, Al, and Si in the table. By using the base material having such a composition, an effect of having both wear resistance and fracture resistance can be obtained.

  Here, the iron-based metal (the total amount when two or more are included) is preferably 3% by weight or more and 25% by weight or less with respect to the weight of the whole substrate, and more preferably the upper limit is 14% by weight. %, And the lower limit is 3.5% by weight. If it is less than 3% by weight, the fracture resistance may be lowered, and if it exceeds 25% by weight, the plastic deformation resistance may be lowered.

  In addition, the third component (the total amount when two or more types are included) is preferably 0.5% by weight or more and 25% by weight or less with respect to the weight of the whole substrate, and more preferably the upper limit is 10%. % By weight, the lower limit being 1% by weight. If it is less than 0.5% by weight, the plastic deformation resistance may be lowered, and if it exceeds 25% by weight, the toughness may be lowered. In the case where two or more elements are included as the third component, their blending ratio is not particularly limited.

  In the present invention, “iron-based metal” refers to at least one metal selected from the group consisting of iron (Fe), cobalt (Co), and nickel (Ni). Further, Cr, V, and Zr are treated as such iron-based metals when dissolved in Co or when present alone as a metal element. However, the content of Cr is preferably less than 0.3% by weight. If the Cr content exceeds this range, the wettability is deteriorated and voids are generated.

<Coating layer>
The surface-coated cutting tool of the present invention includes one or more coating layers that coat the above-described base material. Here, the coating layer covering the base material may be formed so as to cover the entire surface of the base material, or may be formed so as to cover only a part of the base material. means. However, the purpose of forming the coating layer is to improve various characteristics of the cutting tool in the first place. It is preferable to coat at least a part of.

  The thickness of the coating layer of the present invention (when the coating layer is formed by laminating two or more layers) is preferably 0.5 μm or more and 40 μm or less. If the thickness is less than 0.5 μm, the effects of various properties such as wear resistance may not be sufficiently exhibited. On the other hand, if the thickness exceeds 40 μm, further improvements in various properties are not recognized. Is not advantageous. However, as long as economic efficiency is ignored, the thickness may be 40 μm or more, and the effect of the present invention is shown. As a method for measuring the thickness of such a coating layer, for example, it is possible to measure by cutting a surface-coated cutting tool and observing the cross section using an SEM (scanning electron microscope).

  Such a coating layer of the present invention includes at least a lowermost layer as described below, and can include a hard layer and a composition gradient layer.

<Lower layer>
Lowermost layer in contact with the base material of the coating layer in the present invention is composed of a Co chlorine and unavoidable impurities, wherein the thickness is 0.1μm or less than 0.005 .mu.m. By forming such a lowermost layer (particularly including chlorine together with Co), the entire coating layer is made of a base material as compared with the case where a layer made of an intermetallic compound of Co is formed as in Patent Document 3 above. It has extremely strong adhesion to the surface. This is probably because the substrate surface is coated with Co having high adhesion to the coating layer other than the lowermost layer, and chlorine, which is a component of the coating layer, diffuses into the lowermost layer, so that the base material, the lowermost layer, and It is considered that the adhesion between the lowermost layer and the other coating layer is improved. The surface-coated cutting tool of the present invention thus has extremely high adhesion between the coating layer and the substrate, so that various properties such as wear resistance are improved, and the tool life is greatly extended. It has been done.

  Here, it is extremely important to define the thickness of the lowermost layer. When the thickness is less than 0.005 μm, strong adhesion cannot be obtained, and when the thickness exceeds 0.1 μm. Since the lowermost layer itself is brittle, the adhesion to the base material is lowered. More preferably, the upper limit of the thickness of the lowermost layer is 0.07 μm, and the lower limit is 0.02 μm.

  The thickness of the lowermost layer can be determined by combining SEM (scanning electron microscope), TEM (transmission electron microscope), etc. with EDS (fluorescent X-ray elemental analysis), EPMA (electron beam microanalyzer), etc. After exposing the interface between the coating layer and the substrate with a (simple precision film thickness measuring device), it can be measured by a method of observing it with a metal microscope.

  In addition, the lowermost layer of the present invention is characterized by being “formed using a Co-containing raw material”. In other words, the rule “formed using a Co-containing raw material” is that Co constituting the lowermost layer is not a diffused material from the base material (ie, Co constituting the base material diffuses). It is not a thing). As a method for forming the lowermost layer using a raw material containing Co as described above, for example, a chemical vapor deposition method (CVD method) using a raw material gas containing Co, Co particles, or a Co brush is used. Examples thereof include a mechanical processing method. In these methods, a source gas containing Co, Co particles, and a brush made of Co are each “a source containing Co”.

These methods will be described in more detail. First, in the CVD method, hydrogen, hydrogen chloride, argon, nitrogen, titanium tetrachloride, methane (CH (CH) in a sealed vacuum vessel (generator structure) filled with Co at about 50 to 500 ° C. ₄ ), or a mixed gas of two or more of these is introduced as a carrier gas at 1 to 30 liters / minute for 1 to 300 minutes (this time is referred to as keep time in the present invention) to produce a raw material gas containing Co. The lowermost layer can be formed immediately above the base material by continuously introducing it into the CVD film forming apparatus.

  In the mechanical processing method, when Co particles are used (that is, when a blasting method such as drive last is applied), Co particles having a particle size of 10 to 500 μm are used. By treating for about 3 seconds to 20 minutes under the condition of 5 MPa (atmosphere is air), the lowermost layer can be formed immediately above the substrate. On the other hand, when using a Co brush (that is, when applying the brush processing method), using a Co brush with a brush diameter (Co hair part) of φ0.5 to 5 mm, the rotational speed is 500 to 5000 rpm, The lowermost layer can be formed immediately above the substrate by treating for 1 second to 20 minutes under the conditions of a notch of 1 to 10 mm.

  In addition, as the composition of the lowermost layer, as long as it contains chlorine together with Co, it may be composed of only these two components, or may contain other components. Here, the chlorine content is identified by ClKα and CoKα in EDX (energy dispersive X-ray fluorescence analysis), and is expressed as a ratio of Cl atomic% to Co atomic% (Cl atomic% / Co atomic%). In this case, it is preferably 0.01 to 1.5. In addition, the chlorine contained in the lowermost layer may be derived from chlorine (including chlorine in chloride) contained in the carrier gas used when the lowermost layer is formed by the CVD method. Chlorine (including chlorine in chloride) contained in the reaction gas when the coating layer is formed by the CVD method may be diffused. In this regard, when other coating layers are formed by the CVD method, it is possible to diffuse chlorine into the lowermost layer by adjusting the formation conditions, but by physical vapor deposition (PVD method) Chlorine does not diffuse from the other formed coating layers or base materials to the bottom layer.

  Examples of other components that can be included in the lowermost layer include at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron. When these elements are contained, the effect that the adhesion between the base material and the lowermost layer, and the lowermost layer and the other coating layer is further improved can be exhibited. These other elements are considered to diffuse from other coating layers and substrates. These other components can be identified by CKα, NKα, OKα, and BKα in EDX as described above.

  The content of such other components (the sum of two or more components) is 0 when expressed as a ratio of atomic percent of each component to atomic percent of Co (atomic percent of each component / Co atomic percent). 1 to 50 is preferable. In addition, it is preferable that the lowermost layer of this invention does not contain metal components other than Co resulting from a base material and a process except an inevitable impurity. This is because such a metal component other than Co tends to promote a decrease in adhesion between the base material and the lowermost layer.

<Hard layer>
The coating layer of the present invention preferably includes one or more hard layers formed on the lowermost layer, and this hard layer (each layer when two or more layers are formed) is a group IVa in the periodic table. At least one element selected from the group consisting of elements (Ti, Zr, Hf, etc.), group Va elements (V, Nb, Ta, etc.), group VIa elements (Cr, Mo, W, etc.), Al, and Si; It is preferably composed of a compound comprising at least one element selected from the group consisting of carbon, nitrogen, oxygen, boron, and chlorine.

The compounds as described above, for example TiC, TiN, TiCN, TiNO, TiCNO, TiB 2, TiO 2, TiBN, TiBNO, TiCBN, ZrC, ZrO 2, HfC, HfN, TiAlN, AlCrN, CrN, VN, TiSiN, TiSiCN, AlTiCrN, TiAlCN, ZrCN, ZrCNO, Al 2 O 3, AlN, AlCN, ZrN, ZrO 2, TiO 2, TiZrCN, TiAlC, NbC, NbN, NbCN, Mo 2 C, WC, W 2 C, HfO, HfO ₂ , TiCrC, ZrBN, AlHfN, TaN, TaCN, TaC and the like. In addition, when chlorine is contained in these compounds, chlorine may be contained as an interstitial type, may be contained as a substitution type, and may form a compound.

  In the present invention, when the compound is represented by the chemical formula as described above, it is assumed that all the conventionally known atomic ratios are included unless the atomic ratio is particularly limited, and are not necessarily limited to those in the stoichiometric range. . For example, when simply describing “TiCN”, the atomic ratio of “Ti”, “C”, and “N” is not limited to 50:25:25, and also when “TiN” is described, “Ti” and “N” The atomic ratio is not limited to 50:50. These atomic ratios include all conventionally known atomic ratios.

  Of the compounds constituting the hard layer as described above, more preferably, at least one element selected from the group consisting of Ti, Zr, and Hf, and a group consisting of carbon, nitrogen, oxygen, boron, and chlorine It is preferable to select a compound comprising at least one element selected. In particular, it is preferable to form a layer made of these compounds immediately above the lowermost layer. This is because the adhesion between the lowermost layer and the hard layer can be made particularly strong.

  The hard layer of the present invention preferably includes a layer containing α-alumina (alumina having a crystal structure of α type) or κ-alumina (alumina having a crystal structure of κ type) as the above compound. Here, the layer containing α-alumina or κ-alumina is preferably a layer containing α-alumina or κ-alumina as a main component, and in this case, “main component” means α-alumina or It means that 50% by weight or more of κ-alumina is contained. In particular, it is preferable to contain 70% by weight or more of α-alumina or κ-alumina. Thus, by including the layer containing α-alumina or κ-alumina as the hard layer, the wear resistance of the coating layer can be further improved. The crystal structure of alumina can be identified by X-ray diffraction (XRD). Further, such alumina may be doped with IVa group elements such as Zr and Ti.

  The thickness of such a hard layer (thickness per hard layer) is preferably 0.3 μm or more and 30 μm or less, more preferably the lower limit is 0.5 μm or more, further preferably 1 μm or more, and the upper limit is It is suitable that it is 20 μm or less, more preferably 15 μm or less. If the thickness of the hard layer is less than 0.3 μm, it may not be possible to sufficiently improve various properties such as wear resistance. It may not be preferable.

  In addition, it is preferable that the hard layer of this invention is formed by CVD method. As such a CVD method, a conventionally known method can be used without any particular limitation, and the conditions and the like are not limited. For example, a film forming temperature of about 800 to 1050 ° C. can be adopted, and a conventionally known gas such as a nitrile gas such as acetonitrile can be used as the gas to be used without any particular limitation.

  In particular, the coating layer of the present invention preferably includes a layer mainly composed of TiCN formed by chemical vapor deposition (CVD) as a hard layer, and more preferably TiCN formed by MT-CVD. It is preferable to include a layer having a main component. This is because a layer mainly composed of titanium carbonitride (TiCN) having excellent wear resistance can be formed while reducing damage to the substrate based on the application of heat by the CVD method. Here, the layer containing TiCN as a main component means a layer containing 90% by weight or more of TiCN, and preferably includes only TiCN except for inevitable impurities. Further, the MT-CVD (moderate temperature CVD) method is generally performed at about 950 to 1050 ° C., while the normal CVD method as described above is often performed at about 950 to 1050 ° C. This is a method performed at a relatively low temperature.

  The hard layer of the present invention is composed only of at least one element selected from the group consisting of IVa group elements, Va group elements, VIa group elements, Al, and Si in addition to the above-described compounds. It can also be.

  The identification of the composition of the hard layer of the present invention can be confirmed by EPMA-EDS (electron beam microanalyzer-energy dispersive X-ray fluorescence analysis).

<Composition gradient layer>
In the coating layer of the present invention, a composition gradient layer can be formed between the lowermost layer and the hard layer, and the composition gradient layer is formed from the composition of the lowermost layer to the hard layer (on the composition gradient layer). When a plurality of hard layers are formed, a layer whose composition changes in the thickness direction to the composition of the hard layer immediately above the composition gradient layer is preferable. By forming such a composition gradient layer, the adhesion between the lowermost layer and the hard layer can be enhanced. Such a composition gradient layer preferably has a thickness of 0.005 μm or more and 2 μm or less, more preferably a lower limit of 0.01 μm or more, further preferably 0.1 μm or more, and an upper limit of 1 μm or less, more preferably The thickness is preferably 0.5 μm or less. If the thickness of the composition gradient layer is less than 0.005 μm, the adhesion may not be improved, and if it exceeds 2 μm, the characteristics are not significantly improved, which may be industrially undesirable.

  Such a composition gradient layer does not need to be formed independently of the lowermost layer and the hard layer, but usually, depending on the forming method, both layers are formed when the hard layer is formed after the lowermost layer is formed. It is inevitably formed in the middle stage. In other words, the composition gradient layer is observed or not observed depending on the observation conditions, and is usually observed when the observation magnification by a transmission electron microscope (TEM) or the like is set to 2 million times or more. It is what is done.

  In addition, since such a composition gradient layer is formed at the boundary between the lowermost layer and the hard layer, when the boundary between these two layers cannot be clearly defined, the thickness direction in such a composition gradient layer The intermediate point is regarded as the boundary between these layers, and the thickness of each layer is measured.

<Manufacturing method>
This invention also provides the manufacturing method of the surface coating cutting tool provided with the base material which consists of a cemented carbide, and the 1 or more coating layer which coat | covers it. The manufacturing method includes a step of preparing the base material already described above (also referred to as “base material preparation step”), Co and chlorine as the bottom layer in contact with the base material in the coating layer, Forming a lowermost layer having a thickness of 0.005 μm or more and 0.1 μm or less (also referred to as a “lowermost layer forming step”). And this lowest layer formation process is implemented using the raw material containing Co which was already demonstrated above, The above CVD method, a mechanical processing method, etc. are included.

  In addition, as long as the manufacturing method of this invention includes the above processes, it does not interfere even if it includes another process. For example, the process etc. which form a hard layer are included.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Base material>
Base materials A to L were obtained by molding a cutting edge-exchangeable cutting tip having a shape of CNMA120408 (JIS B4120 1998) using the cemented carbide described in Table 1 below (base material preparation step). The balance of the components listed in Table 1 is tungsten carbide (WC), i.e., these cemented carbides contain tungsten carbide, an iron-based metal, and a third component. For example, “(Ti, Ta, Nb, Mo) C” in the base material B indicates that 3.8% by weight of carbides whose metal components are Ti, Ta, Nb, and Mo is contained (other bases). In the material, each notation has the same meaning as this).

<Formation of the lowest layer>
By applying any one of the lowermost layer forming methods 1 to 8 described in the following Table 2 and Table 3 to each of the base materials described in Table 1 above, the entire surface or a partial surface (Table The method described in 2 can be formed on the entire surface of the base material, but the brush processing method shown in Table 3 can be processed only on the surface that is easy to cut the edge and the flank surface, and the blasting method does not process the inside of the hole). (Lowermost layer forming step). That is, Table 2 shows a method of forming the lowermost layer by a CVD method using a source gas containing Co as a raw material containing Co (formation methods 1 to 4), and Table 3 shows the lowermost layer by a mechanical processing method. (Formation methods 5 and 6 show a drive last method (normal temperature, pressure 1.0 MPa, atmosphere is air) using Co particles (particle size: 50 μm) as a raw material containing Co. Methods 7 and 8 are brush processing methods using a Co brush (brush diameter: φ1.5 mm) as a raw material containing Co (rotation speed: 1500 rpm, cutting: 2 mm). In addition, it shows that the mixed gas (flow rate: hydrogen 7 liter / min, hydrogen chloride 3 liter / min) which consists of hydrogen and hydrogen chloride was used for the carrier gas of the formation method 3 of Table 2.

  The thickness and composition (Cl atom% / Co atom%) of the lowermost layer thus formed are shown in Table 6 described later. The thickness of the lowermost layer was measured by a method in which the interface between the coating layer and the substrate was exposed by a calotest and observed with a metal microscope. The composition of the lowermost layer (that is, the chlorine content) is calculated from the CoKα and ClKα peaks in EDX, and indicates the ratio of Cl atom% to Co atom%.

<Formation of hard layer>
With respect to the precursor of the surface-coated cutting tool in which the lowermost layer is formed on the base as described above, each of the hard layers a to d described in Table 4 below is either entirely or partially on the lowermost layer. Formed. For example, in the hard layer a in Table 4, a layer made of TiN having a thickness of 0.5 μm is formed as the second layer on the lowermost layer, and a layer made of TiCN having a thickness of 3.0 μm is formed thereon as the third layer. And a layer made of TiZrCN with a thickness of 2.5 μm is formed as a fourth layer thereon, a layer made of TiCNO with a thickness of 1.0 μm is formed thereon as a fifth layer, and a layer as a sixth layer is formed thereon. It shows that a layer made of α-alumina having a thickness of 2.5 μm was formed, and a layer made of ZrN having a thickness of 1.0 μm was formed thereon as the seventh layer. The same applies to the other hard layers b to d. In Table 4, “TiCN” indicates a layer made of TiCN (ie, a layer mainly composed of TiCN) formed by MT-CVD, and “α-Al ₂ O ₃ ” is mainly composed of α-alumina. “Κ-Al ₂ O ₃ ” indicates a layer mainly composed of κ-alumina. The sixth layer of the hard layer c indicates that it is composed of a mixture of α-alumina and zirconium and / or zirconium oxide.

  And each layer of such a hard layer was formed by CVD method which employ | adopted the conditions shown in the following Table 5. FIG.

<Surface coated cutting tool>
As described above, No. 1 shown in Table 6 below. 1 to 24 surface-coated cutting tools of the examples of the present invention were produced. Similarly, No. 1 shown in Table 6 below. The surface-coated cutting tool of 1-4 comparative examples was manufactured. For example, in No. 6 of Table 6, The surface-coated cutting tool No. 1 uses “Substrate A” shown in Table 1 as the base material, and the lowermost layer (composition (Cl atom) having a thickness of 0.005 μm by “Formation Method 1” shown in Table 2 on the base material. % / Co atomic%) is 0.01), and the “hard layer a” shown in Table 4 is formed as the hard layer on the lowermost layer (that is, the second layer of the hard layer a is formed on the lowermost layer). It was formed, and the seventh layer was sequentially formed thereon). The comparative example No. 1 and no. The surface-coated cutting tool of 2 indicates that the lowermost layer was not formed.

  As is clear from the composition of the lowermost layer in Table 6 (Cl atom% / Co atom%), No. The lowermost layer of the surface-coated cutting tool of Examples 1 to 24 contains Co and chlorine.

<Performance evaluation>
The surface-coated cutting tool obtained as described above was subjected to a continuous cutting test and an intermittent cutting test under the following conditions to evaluate the degree of adhesion between the substrate and the coating layer. The results are shown in Table 7 below.

<Conditions for continuous cutting test>
Holder used: PCLNR2525-43 (Sumitomo Electric Hardmetal)
Work material: SCM435 (HB = 246) round bar Cutting speed: 240 m / min.
Feed: 0.26 mm / rev.
Cutting depth: 2.0mm
Wet / dry: wet (water-soluble oil)
Evaluation: The time (minutes) until the cutting edge was broken due to the progress of wear on the rake face side was determined. The longer the time, the better the wear resistance, and the stronger the adhesion between the substrate and the coating layer.

<Conditions for intermittent cutting test>
Holder used: PCLNR2525-43 (Sumitomo Electric Hardmetal)
Work material: SCM435 (HB = 246) Square material Cutting speed: 220 m / min.
Feed: 0.21 mm / rev.
Cutting depth: 1.5mm
Cutting time: 2 minutes Wet / dry: Dry Evaluation: A test was performed with 10 cutting edges, and the number of missing cutting edges was determined. The smaller the number of missing cutting edges, the stronger the adhesion between the substrate and the coating layer.

  As is clear from Table 7, it was confirmed that the surface-coated cutting tool of the example of the present invention had stronger adhesion between the base material and the coating layer than the surface-coated cutting tool of the comparative example. That is, in Comparative Examples 1 and 2 in which the lowermost layer was not formed, and in Comparative Examples 3 and 4 in which the thickness of the lowermost layer was not specified in the present invention, both had poor adhesion between the base material and the coating layer. . Therefore, in the surface-coated cutting tool of the example, such an excellent effect is shown because the lowermost layer in contact with the base material of the coating layer contains Co and chlorine, and the thickness is 0.005 μm or more. It is apparent that the thickness is 0.1 μm or less and is formed using a raw material containing Co.

  Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims (10)

A surface-coated cutting tool comprising a substrate made of a cemented carbide and one or more coating layers covering the substrate,
The lowermost layer in contact with the base material of the coating layer is composed of a Co chlorine and unavoidable impurities state, and are more 0.1μm or less thickness of 0.005 .mu.m,
The Co is a surface-coated cutting tool that is not a diffused material from the base material . A surface-coated cutting tool comprising a substrate made of a cemented carbide and one or more coating layers covering the substrate,
The lowermost layer in contact with the substrate of the coating layer is made of Co, chlorine, at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron, and unavoidable impurities, and has a thickness of 0. 0.005 μm or more and 0.1 μm or less,
The Co is a surface-coated cutting tool that is not a diffused material from the base material . The coating layer includes one or more hard layers formed on the lowermost layer,
The hard layer is composed of at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and carbon, nitrogen, oxygen, boron, and chlorine. The surface-coated cutting tool according to claim 1 or 2, comprising a compound comprising at least one element selected from the group.   The hard layer is made of a compound composed of at least one element selected from the group consisting of Ti, Zr, and Hf and at least one element selected from the group consisting of carbon, nitrogen, oxygen, boron, and chlorine. The surface-coated cutting tool according to claim 3 configured.   The surface-coated cutting tool according to claim 3 or 4, wherein the hard layer includes a layer mainly composed of TiCN formed by a chemical vapor deposition method.   The surface-coated cutting tool according to claim 3, wherein the hard layer includes a layer containing α-alumina or κ-alumina.   The surface-coated cutting tool according to claim 1, wherein the lowermost layer has a ratio of atomic percent of Cl to atomic percent of Co of 0.01 to 1.5. A composition gradient layer is formed between the lowermost layer and the hard layer,
The surface-coated cutting tool according to any one of claims 1 to 7, wherein the composition gradient layer is a layer whose composition changes in the thickness direction from the composition of the lowermost layer to the composition of the hard layer. The base material is a cemented carbide containing tungsten carbide, an iron-based metal, and a third component,
The third component includes at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al, and Si in the periodic table, and a group consisting of carbon, nitrogen, oxygen, and boron. A compound comprising at least one element selected from the group consisting of at least one element and / or at least one element selected from the group consisting of group IVa element, group Va element, group VIa element, Al and Si in the periodic table. Item 9. The surface-coated cutting tool according to any one of Items 1 to 8. A method for producing a surface-coated cutting tool comprising a substrate made of a cemented carbide and one or more coating layers covering the substrate,
Preparing the substrate;
As the lowermost layer in contact with the base material of the covering layer consists of a Co chlorine and unavoidable impurities, saw including a step of thickness to form a bottom layer which is less 0.1μm least 0.005 .mu.m,
Said Co is not the diffused material from a base material , The manufacturing method of the surface coating cutting tool.