JP2007290180A - Cutting tool for wood - Google Patents

Abstract

An object of the present invention is to provide a cutting tool for cutting wood that can exhibit excellent effects in terms of sharpness and life.
A cutting tool for cutting wood has a hard coating of two layers (a layer and b layer) having different compositions on one side or both sides of a flank and a scooping surface, and the a layer of the hard coating is a metal. In the atomic% of only the component, Si is 10% or more and 60% or less, and B, Al, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W or less is less than 10%. Any of nitride, carbonitride, oxynitride, and oxycarbonitride composed of the remaining Ti, and Si ₃ N ₄ and Si are present in the compound as independent phases, In the layer b, the atomic percentage of the metal component alone is more than 40% and 75% or less of Al, and one or more of B, Si, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W are used. Of nitride, carbonitride, oxynitride, oxycarbonitride composed of the remaining Ti. And in either displacement, and, b layer directly above the surface of the blade base material.
[Selection figure] None

Description

  The present invention relates to a cutting tool for cutting wood such as a cutting tool for rotary cutting and a cutting tool for planing used for cutting wood.

  The cutting edge of wood has been coated with various materials for the purpose of improving sharpness and further extending the cutting life, and many proposals have been made so far.

For example, in Japanese Patent Application No. 1-75889 (see Japanese Patent Application Laid-Open No. 2-252501) and Japanese Patent Application No. 2-257864 (see Japanese Patent Application Laid-Open No. 4-135107), high-speed tool steel, high chromium alloy tool steel, etc. One of the tool steel and the cemented carbide is used as a blade base material, and chromium nitride (hereinafter simply referred to as “CrN”) composed of CrN, Cr ₂ N, or a mixture of CrN and Cr ₂ N is formed on either the flank face or the scooping face. Only a thickness of 0.5 to 6.0 μm (Japanese Patent Application No. 1-75889) or 0.2 to 6.0 μm (Japanese Patent Application No. 2-257864) was provided on the “chromium nitride”) A wood cutting tool (rotary cutting tool or flat cutting tool) is disclosed, and the wood cutting tool provided with such a coating layer has reduced wear on the blade edge of the coating layer and has no conventional coating layer. Compared to sharpness and lifespan It is known that the excellent effect is exhibited.
JP-A-2-252501 JP-A-4-135107

  The wood cutting blade provided with the coating layer described in the above-mentioned publication has reduced wear on the blade edge of the coating layer, and has an excellent effect on sharpness and life compared to a conventional one without a coating layer. However, there is a strong demand for a wood cutting blade that has a sharpness and a longer life than these wood cutting blades.

  Accordingly, an object of the present invention is to provide a wood cutting blade that can exhibit an effect superior to that of the conventional example in terms of sharpness and life.

  By the way, the sharpness and life of a cutting tool for wood cutting are generally determined by the degree of occurrence of defects (missing, fluffing, reverse blur) of wood cutting skin. On the other hand, this can be evaluated by cutting edge wear when viewed from the blade side.

In this regard, the above-mentioned conventional technology can provide a corresponding effect by coating chromium nitride, but in the present invention, various cutting tests are repeated to develop an oxidation resistance of the hard coating in order to develop a better wood cutting blade. As a result of detailed examination of the influence of various elements on the wear resistance and adhesion and the layer structure of the film, nitrides, carbonitrides, oxynitrides mainly containing Ti containing an appropriate amount of Si Or oxycarbonitride (hereinafter referred to as TiSi nitride) and nitride, carbonitride, oxynitride or oxycarbonitride (hereinafter referred to as TiAl nitride) mainly composed of Ti and Al Each of the coatings in which the metal component contained in the metal is limited to a specific value is alternately coated, and in this case, the coating such as the TiAl nitride is directly above the surface of the base material, and the fine TiSi nitride is fine. The tissue structure is mainly composed of Ti Nitrides, carbonitrides, in the oxynitride or oxycarbonitride thereof, by film formation so as to present as phase Si ₃ N ₄ and Si are independent, more effectively inhibiting the progression of wear Knowing that it is possible to complete the present invention.

Here, the present invention is a wood cutting tool using any one of tool steel such as high-speed tool steel and high chromium alloy tool steel and cemented carbide as a blade base material, which is either a flank or scoop surface. The hard coating of two layers (a layer and b layer) having different compositions is coated on one side or both sides, and the a layer of the hard coating is atomic% of only the metal component, and Si is 10% or more and 60% or less. N, B, Al, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W and less than 10%, and nitride and carbonitride composed of the remaining Ti , An oxynitride, and an oxycarbonitride, and Si ₃ N ₄ and Si are present in the compound as independent phases, and the b layer of the hard coating contains only 40% of Al in the metal component. %, 75% or less, and B, Si, V, Cr, Y, Zr, Nb, Mo, Hf, One or more of a, W and less than 10%, and any one of nitride, carbonitride, oxynitride, oxycarbonitride composed of the remaining Ti, and the b layer is The cutting tool for cutting wood is characterized by being directly above the surface of the cutting tool base material.

  Moreover, it is preferable that the a layer and the b layer are alternately coated on the blade base material one or more layers.

  The cutting tool for cutting wood according to the present invention has superior oxidation resistance and wear resistance compared to the cutting tool of the conventional example, so that a much longer tool life can be obtained in cutting of wood, and productivity in cutting can be improved. It is extremely effective for improvement.

  First, the constituent requirements of one a layer of two layers having different compositions described in the claims will be described in detail. In general, when an oxidation test is performed on the CrN film in the air, Cr diffuses outward in the vicinity of the film surface, and forms a chromium oxide layer there. According to the study by the present inventors, this is considered to be the reason for improving the oxidation resistance. At this time, when this chromium oxide layer is exposed to a more severe wear condition, that is, in a high temperature atmosphere, it is porous. Oxide crystals are formed. In the static oxidation test, the chromium oxide layer formed on the outermost surface functions as an oxidation protective film against the inward diffusion of oxygen, which is the progress of oxidation. The chromium oxide layer easily peels off from the porous structure and does not exhibit a sufficient effect on the progress of oxidation.

  However, TiSi-based nitrides have not only extremely high oxidation resistance of the film itself, but also a very dense complex oxide layer containing Si that serves as an oxidation protective film is formed on the outermost surface. Confirmed that no porous Ti oxide that would cause the oxide protective film to peel off was formed. In order to obtain the above effect, Si must be contained in an atomic percentage of only the metal component of the film and not less than 10%. Conversely, if it exceeds 60%, the ductility or hardness of the film is significantly reduced. It becomes impossible to endure the use as a cutting blade.

  B, Al, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W contained in the a layer function as a solid solution strengthening element in the film such as TiSi nitride, and increase the hardness of the film. It is valid. If necessary, it is desirable to add a trace amount of one or more of B, Al, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W. However, if 10% or more is added as atomic% of only the metal component of the film, the effect of improving the oxidation resistance due to the Si content cannot be obtained. Therefore, B, Al, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W are one kind or two kinds or less and less than 10%.

Further, the microstructure of the a layer should have a structure in which Si ₃ N ₄ and Si exist as independent phases in nitride, carbonitride, oxynitride or oxycarbonitride containing Ti as a main component. Can achieve high hardness, and a film with extremely excellent wear resistance can be obtained. In order to form a film having such a structure, that is, the a layer, the basic specifications of the film forming apparatus are the same even when the physical vapor deposition method such as arc discharge ion plating or sputtering is used or the same method is used. Although the absolute value differs depending on the condition, it can be achieved by setting the bias voltage applied to the substrate to a relatively low value such as -10 to -100 V during coating.

  The role of Al in the other b layer is to improve the wear resistance and oxidation resistance of the coating. The lower the Al content in the film, the better the adhesion between the base material and the film. However, when the Al content is only 40% or less of the metal component of the film, the film has wear resistance and oxidation resistance. The effect of improving is not obtained. However, when the content exceeds 75%, not only the adhesion between the base material and the film is deteriorated, but also the hardness of the film is lowered, and the wear resistance required for the tool cannot be obtained. Therefore, in order to obtain a good balance of adhesion, wear resistance, and oxidation resistance, it is important to adjust the Al content of the b layer to more than 40% and 75% or less in terms of atomic% of the metal component alone. It is.

  B, Si, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W function as a solid solution strengthening element in a film such as a TiAl nitride, and are effective in increasing the hardness of the film. Therefore, it is desirable to add a trace amount of one or more of B, Si, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W as necessary. However, if 10% or more is added as the atomic% of only the metal component of the film, the adhesion between the base material and the film decreases. Therefore, in order to obtain adhesion, wear resistance, and oxidation resistance with a good balance, B, Si, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, and W are one type or two or more types. %.

  As described above, in the present invention, a b layer having a good balance between adhesion to the base material, wear resistance and oxidation resistance of the coating itself is coated directly on the surface of the base material, and on top of that, remarkably oxidation resistance, It is extremely important to coat the layer a having excellent wear resistance, and as a result, it is possible to effectively suppress the progress of wear of the coating layer in the vicinity of the blade edge, and to improve the sharpness and lifetime over a long period of time. .

  The same effect can be obtained by a multilayer coating in which the a layer and the b layer are alternately laminated after the b layer is coated directly on the surface of the base material. Moreover, each layer can be adjusted to any of nitride, carbonitride, oxynitride, and oxycarbonitride as required, and the same effect can be obtained with a wood cutting blade coated therewith. The cutting tool for cutting wood according to the present invention is not particularly limited, but the thermal effect on the coating base material, the fatigue strength of the cutting tool, the adhesion of the film, and the matching between the a layer and the b layer. In consideration of the properties, etc., it should be a physical vapor deposition method that can be applied at a relatively low temperature and that a bias voltage is applied to the coating base material side such as arc discharge ion plating or sputtering, in which compressive stress remains in the coated film. Is desirable.

The present invention can be applied to a wide variety of cutting tools for cutting wood such as a throwing blade that is molded or re-polished from either the flank face or the scooping face as well as the throwaway blade.
(Example)
Next, examples of the present invention will be described more specifically together with comparative examples and conventional examples.

The hard coatings of the present invention and the comparative example were formed as follows. That is, using a small arc ion plating apparatus, a target film can be obtained from various alloy targets which are evaporation sources of metal components and N ₂ gas, CH ₄ gas and Ar / O ₂ mixed gas which are reaction gases And the film is formed on the cemented carbide wood processing blade as a coated substrate so that the thickness of the entire coating is 4 μm under the conditions of a coated substrate temperature of 400 ° C. and a reaction gas pressure of 3.0 Pa. went. In all of the examples of the present invention and Comparative Examples 51 to 58, the film was formed by applying a bias voltage of −30 V. However, in Comparative Example 59, the film was formed by applying a bias voltage of −200 V. Further, all the conventional examples were formed by applying a bias voltage of −100V.

Table 1 shows examples of the present invention, Table 2 shows comparative examples, and Table 3 shows details and hard cutting results of conventional hard coatings. The presence or absence of Si ₃ N ₄ and Si in the layer a of the hard coating of the present invention was confirmed by XPS, and the coating in which the presence of Si ₃ N ₄ and / or Si was recognized was shown in the table. . In addition, the description regarding Tables 1-3 is mentioned later.

The numbers immediately after Ti, Si, Al, etc. in Table 1 represent the atomic% of the immediately preceding element. For example, Ti77Si23 is Ti having an atomic% of 77 and Si having an atomic% of 23. Means that. In Tables 1 and 2, Si ₃ N ₄ is expressed as Si ₃ N ₄ . Further, in Table 3, Cr ₂ N is expressed as Cr ₂ N.

Next, cutting will be described. Until the tool becomes incapable of cutting due to chipping or wear of the cutting edge under the following cutting conditions using the hard film-coated woodworking blade formed as described above. Machining was performed, and the machining time at that time was defined as the tool life. The used cutter was a replaceable blade type cutter, and a two-blade (17 × 12 × 1.5 mm thickness) having a nominal CAMOS and a cutter outer diameter of Φ75 mm was used. The machine used for the evaluation was a precut machine (Precut Machine FK series manufactured by Heian Corporation). A spare blade type cutter for males and females was attached to the rotating main shaft, and a variety of processing was carried out, such as a seat ant joint as a wooden house member, a large insert al joint, a seat hook joint, a joist carving, and a general flat tenon. Cutting was performed at a rotational speed of 9000 RPM and a feed rate of 2 m / min. I went there.

  As is clear from Tables 1, 2 and 3, the examples of the present invention have a significantly improved tool life as compared with the comparative example and the conventional example, and it can be understood that the present invention sufficiently corresponds to the cutting of wood. . In Comparative Example 52, the composition of the film is included in the present invention. However, since the layer structure of the film is different, peeling of the film occurred early in wood cutting, and the life was extremely short. In Comparative Example 59, the composition and layer structure of the film are included in the present invention, but since only the Si phase is present in the a layer, sufficient film hardness cannot be obtained, and the present invention example The service life was shorter than When the Al content in the b layer was remarkably high as in Comparative Example 57, peeling occurred from the interface between the base material and the b layer during cutting, resulting in an extremely short life.

Claims (2)

A cutting tool for cutting wood that uses either high-speed tool steel, high-chromium alloy tool steel, or other tool steel and cemented carbide as its base material, and the composition differs on one or both sides of the flank and scoop surface 2 layers (a layer and b layer) are coated, the a layer of the hard coating is an atomic% of only the metal component, Si is 10% or more and 60% or less, B, Al, One, two or more of V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W and less than 10%, and the remaining Ti is composed of nitride, carbonitride, oxynitride, acid charcoal One of the nitrides, Si ₃ N ₄ and Si are present in the compound as independent phases, and the b layer of the hard coating has an atomic% of only the metal component and Al is more than 40% and 75% or less. , B, Si, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W It is any of nitride, carbonitride, oxynitride, oxycarbonitride composed of remaining Ti and less than 10%, and the b layer is directly above the surface of the blade base material A cutting tool for cutting wood, which is characterized by the above.   2. The cutting tool for wood cutting according to claim 1, wherein the a layer and the b layer are alternately coated on the cutting tool base material one or more layers.