JP5945950B2 - Hard film coated cutting tool - Google Patents

Description

  The present invention relates to a cutting tool coated with a hard film made of Ti (titanium) nitride and carbonitride.

In general, cutting tools represented by drills and end mills are coated with various hard coatings such as DLC (diamond-like carbon) and titanium compounds in order to improve wear resistance and toughness. Regarding the selection of these hard coatings, from various viewpoints such as adhesion to cutting tool grades (high-speed tool steel, cemented carbide, etc.) and whether or not stable lamination is possible in the case of multilayer films It is determined.

  Among these, hard coatings made of Ti nitride or carbonitride are widely used in various cutting tools because they can be coated on a wide variety of materials and can be coated with a multilayer film relatively easily. For example, Patent Document 1 is a cutting tool in which a hard film composed of at least one of a nitride and carbonitride containing Ti is coated on a cemented carbide substrate. The hard film contains 0.01% by mass to 1% by mass of an inert gas, and among the peaks detected by the X-ray diffraction method, the peak intensity A of the (111) crystal plane of the hard film and ( 200) A cutting tool is disclosed in which (A / B), which is a ratio to the peak intensity B of a crystal plane, satisfies the relationship 1.1 <(A / B) <10.0. This cutting tool has the characteristics that high hardness can be obtained and wear resistance can be improved without reducing the adhesion of the hard coating.

  Moreover, in patent document 2, it is a cutting tool which coat | covered the TiN (titanium nitride) layer, the TiCN (titanium carbonitride) layer, and the TiN layer in order from the surface of the cemented carbide (base material), Comprising: The crystal plane that is the maximum peak intensity of the TiN layer is the (hkl) crystal plane, and the peak intensity I (hkl) of the (hkl) crystal plane of the TiCN layer and (422) the peak intensity I (422) of the crystal plane A cutting tool is disclosed in which R on the top surface side of the TiCN layer of the cutting tool is larger than R on the TiN layer side (in the TiCN layer) where R is the ratio I (422) / I (hkl). Yes. This cutting tool is characterized in that the hard coating does not peel off during intermittent cutting, has a long life, and has both chipping resistance and chipping resistance.

JP 2006-150583 A JP 2006-297583 A

However, in the cutting tool disclosed in Patent Document 1, if a drill is produced under the condition of satisfying the relationship of 1.1 <A / B <10.0, the drill is continuous in a film having a large crystal distortion and softening. There was a problem that the toughness of the film could not withstand the cutting process, resulting in a decrease in life.

In the cutting tool shown in Patent Document 2, the peak intensity ratio (I (422) / I (hkl)) in the TiCN layer is I (hkl) is I (111). In this case, the peak of I (111) is the maximum, and the ratio of the peak intensities appearing on I (111) and other crystal planes is preferably smaller than 10. However, in this respect, the crystal orientation ratio is not suitable as a coating for continuous cutting as in the case of Patent Document 1 described above, and as a coating for a tool to which a significant impact is applied every processing. As a result, the toughness of the coating has poor resistance to processing phenomena, and there is a problem that premature wear and breakage are likely to occur.

Accordingly, an object of the present invention is to provide a hard film coated cutting tool having a long life in continuous cutting.

In order to solve the above-described problems, the present inventor pays attention to a cutting tool coated with a hard coating made of Ti nitride and carbonitride, and in particular, the lowermost layer (first hard coating) and the intermediate layer (second In the case of a hard film composed of three layers, the outermost layer (third hard film) and the outermost layer (third hard film), the present inventors have intensively studied a hard film whose intermediate layer (second hard film) is Ti carbonitride. As a result, it was found that the wear resistance of the cutting edge is improved when the peak intensity ratio of the plurality of crystal planes during X-ray diffraction of the Ti carbonitride hard film has a specific relationship.

Accordingly, in the present invention, there is provided a hard film-coated cutting tool that coats the first and third hard films made of Ti nitride and the second hard film made of Ti carbonitride. The hard film is coated from the base material side of the tool in the order of the first hard film, the second hard film, and the third hard film. The second hard film is the (111) crystal plane at the time of X-ray diffraction. When the peak intensity of h (111) / h (200), which is the ratio of each peak intensity, is represented by h (111), the peak intensity of the (200) crystal plane is represented by h (200) A hard film-coated cutting tool which is a hard film satisfying the relational expression of H ≦ 50 was obtained. By using the hard coating-coated cutting tool according to the present invention, the wear resistance of the hard coating is improved.

The invention according to claim 2 is a hard film-coated cutting tool in which the first hard film is TiN and the third hard film is Ti ₂ N. By forming the hard film-coated cutting tool according to the present invention, the outermost layer (third hard film) having high hardness and excellent wear resistance is formed on the lowermost layer (first hard film) rich in toughness. Is done.

As described above, since the wear resistance of the hard coating is improved by using the hard coating-coated cutting tool according to the present invention, there is an effect that it has a long life even in continuous cutting. In addition, by using a hard coating coated cutting tool in which the first hard coating is TiN and the third hard coating is Ti ₂ N, on the bottom layer (first hard coating) rich in toughness, the hardness is high. Since the outermost layer (third hard film) with excellent wear resistance is formed, the effect of preventing sudden life reduction such as chipping of the cutting edge while suppressing the progress of wear of the cutting edge during the cutting process. Play.

It is a schematic cross section of the cutting tool surface which coat | covered the hard film which concerns on this invention.

  An example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a cutting tool surface coated with a hard coating according to the present invention. As shown in FIG. 1, the hard coating coated cutting tool 1 according to the present invention comprises Ti nitride (the lowermost layer) in order from the base material (base material) 2 side made of cemented carbide or high-speed tool steel. First hard film 3), hard carbon film 10 made of Ti carbonitride (second hard film 4) as an intermediate layer and Ti nitride (third hard film 5) as the outermost layer is coated. ing. Hereinafter, the first to third hard coatings will be described in detail.

Ti nitride (first hard film) as the lowermost layer is a hard film that directly covers the surface of the base material of the cutting tool, and is made of Ti on the surface of the base material that has been subjected to ion bombardment treatment with argon gas. Coating is performed by introducing nitrogen gas into the vacuum chamber in which the target is installed. The film thickness of the first hard film is preferably in the range of 0.3 μm to 0.8 μm from the point where the second and third films are laminated. The first hard coating is preferably titanium nitride (TiN) from the viewpoint of directly covering the cutting tool surface.

Ti carbonitride (second hard film) as an intermediate layer is a hard film directly coated on the first hard film, such as nitrogen gas and acetylene in a vacuum chamber in which a Ti target is installed. It is formed by introducing a hydrocarbon-based gas. The film thickness of the second hard film is preferably in the range of 2.0 μm to 2.5 μm from the point of lamination in a state sandwiched between the first and third hard films in the vertical direction. In addition, the second hard coating does not come into contact with the cutting tool surface or the work material, and when the first and third hard coatings are made of TiN, carbonitriding from the viewpoint of improving the adhesion with TiN. Titanium (TiCN) is preferable. In addition, the second hard coating constitutes titanium carbonitride (TiCN) by changing the deposition conditions such as the reduced pressure atmosphere in the deposition chamber (chamber) and the bias voltage to the titanium target during the deposition process. It is more preferable to use a multilayer film having different constituent ratios of carbon (C) and nitrogen (N).

For the second hard film, when the peak intensity of the (111) crystal plane at the time of X-ray diffraction using a copper target is h (111) and the peak intensity of the (200) crystal plane is h (200) When h (111) / h (200), which is the ratio of the respective peak intensities, satisfies the relational expression of 20 ≦ h (111) / h (200) ≦ 50, the wear resistance on the flank of the cutting tool is improved. improves. Further, from the viewpoint of achieving both long life and improved wear resistance, the above relational expression preferably satisfies the relationship of 30 ≦ h (111) / h (200) ≦ 50.

The Ti nitride (third hard film) as the outermost layer is a hard film directly coated on the second hard film, and a vacuum in which a Ti target is installed as in the case of the first hard film. It is formed by introducing nitrogen gas into the chamber. The film thickness of the third hard film is preferably in the range of 0.1 μm to 0.5 μm from the point of lamination on the second hard film. The third hard coating is preferably dititanium nitride (Ti ₂ N) from the point of being the outermost layer of the cutting tool.

TiN (film thickness: 0.5 μm) as the first hard film, TiCN (film thickness: 2.0 μm) as the _second hard film, and Ti ₂ N (film thickness: 2.0 μm) as the second hard film in order from the base material surface of the drill. Each hard film (total film thickness: 2.8 μm) having a film thickness: 0.3 μm) under various different film formation conditions (pressure in the vacuum chamber: 0.5 to 0.6 Pa, bias voltage: 50 to 150 V) Coated drill no. A drilling test (hereinafter referred to as the main test) was performed using 1 to 12 (12 in total). The results will be described with reference to Table 1. Table 1 shows the peak strength ratio H and hardness of the hard coating (second hard coating) of the drill used when this test was conducted using a drill coated with a hard coating under different film forming conditions (12 levels in total). The hardness of the film (unit: Vickers hardness Hv) and the wear width of the second surface of the drill (unit: μm) are shown. Further, this test was performed under the following test conditions.
・ Tool used: Drill made of high-speed tool steel (drill diameter 6.0 mm)
-Work material: Carbon steel S50C (Brinell hardness: 180HB)
・ Cutting speed: 40 m / min
・ Feed amount: 0.18mm / rev
・ Rotation speed: 2100 min ^-1
・ Number of processed holes: 100 holes

  As shown in Table 1, the drill No. in which the value of the peak intensity ratio H of the hard coating (second hard coating) is in the range of 2.2 to 14.6. 1 to 6 and a drill No. having a peak intensity ratio H of 55.6. The wear width of the second face of each drill using No. 12 was in the range of 25.3 μm to 43.9 μm. On the other hand, the drill No. in which the value of the peak intensity ratio H of the hard coating (second hard coating) of the present invention is in the range of 22.3 to 48.7. The wear width of the second surface of each of the drills 7 to 11 was in the range of 11.7 μm to 21.8 μm. From the above results, the wear width of the second surface of the drill can be reduced by using a drill having a peak strength ratio H of the hard coating (second hard coating) of the present invention of 20 or more and 50 or less. It was.

Next, TiN (film thickness: 0.5 μm) as the first hard film, TiCN (film thickness: 2.1 μm) as the second hard film, and the first hard film in the order from the base material surface of the end mill, as in Example 1. 3 hard coatings (total film thickness: 2.9 μm) of Ti ₂ N (film thickness: 0.3 μm) as various hard film forming conditions (pressure in the vacuum chamber: 0.5 to 0.6 Pa). , Bias voltage: 50 to 150 V). A cutting test (hereinafter referred to as the main test) was performed using 1 to 12 (12 in total). The result will be described with reference to Table 2. Table 2 shows the peak intensity ratio H of the hard film of the end mill (second hard film), the hard film when this test was performed using an end mill coated with a hard film under different film forming conditions (12 levels in total). (Unit: Vickers hardness Hv) and end mill flank wear width (unit: μm) are shown respectively. Further, this test was performed under the following test conditions.
・ Tool used: High speed tool steel, 2-flute end mill (end mill diameter 10.0 mm)
-Work material: Carbon steel S50C (Brinell hardness: 180HB)
・ Cutting speed: 41 m / min
・ Feed amount: 0.065mm / rev
・ Cut amount (aa × ae): 15 mm × 2.5 mm
・ Total cutting length: 5m

  As shown in Table 2, the end mill No. in which the value of the peak intensity ratio H of the hard film (second hard film) is in the range of 3.9 to 16.6 is shown. 1 to 6 and an end mill No. having a peak intensity ratio H of 57.9. The wear width of the flank face of each end mill using 12 was in the range of 150 μm to 189 μm. On the other hand, the end mill No. in which the value of the peak intensity ratio H of the hard coating (second hard coating) according to the present invention is in the range of 23.8 to 46.9. The wear width of the flank face of each of the end mills 7 to 11 was in the range of 130 μm to 139 μm. From the above results, it is possible to reduce the wear width of the flank face of the end mill by using an end mill having a peak strength ratio H of 20 to 50 in the hard coating (second hard coating) according to the present invention. did it.

1 Hard Film Coated Cutting Tool 2 Base Material (of Hard Film Coated Cutting Tool) 3 First Hard Film 4 Second Hard Film 5 Third Hard Film 10 Hard Film

Claims (2)

A hard film-coated cutting tool coated with a first and third hard film made of Ti nitride and a second hard film made of Ti carbonitride, wherein the first to third Are coated in the order of the first hard film, the second hard film, and the third hard film from the base material side of the hard film-coated cutting tool. The peak intensity of the (111) crystal plane during X-ray diffraction is expressed as h (111), the peak intensity of the (200) crystal plane is expressed as h (200), and h (111) / A hard film-coated cutting tool characterized by being a hard film satisfying a relational expression of 20 ≦ H ≦ 50 when h (200) is H. The hard coating-coated cutting tool according to claim 1, wherein the first hard coating is TiN, and the third hard coating is Ti ₂ N.

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