JP6062623B2 - Cutting tools - Google Patents

Description

  The present invention relates to a cutting tool formed by forming a coating layer on the surface of a substrate.

  Currently, cutting tools are used to improve slidability, wear resistance, and fracture resistance by forming various coating layers on the surface of hard materials such as WC-based cemented carbide and TiCN-based cermet. In particular, a coating layer formed by physical vapor deposition has high hardness and high wear resistance, and is widely used for various applications.

  Recently, in such a physical vapor deposition method, a plurality of types of targets having different compositions are mounted in a chamber to evaporate metal elements having different compositions from each target, and a coating layer is formed while rotating a sample stage on which the sample is placed. A coating layer having a multilayer structure in which the metal composition changes with an extremely thin layer thickness by forming a film has been proposed. By adjusting the composition of the target, the hardness, lubricity, and heat resistance of the coating layer are proposed. For example, Patent Document 1 discloses a coating layer having a cubic X-ray diffraction pattern as a whole of a laminate in which two types of compound layers are laminated in multiple layers. Yes.

  Patent Document 2 discloses a hard film covering member having an intermediate laminated portion in which A layers and B layers represented by (AlCrTiSi) N or the like are alternately laminated, and FIG. Diffraction peak from the plane (Peak 1), diffraction peak from the (111) plane of the A layer (Peak 2), diffraction peak from the (200) plane of the B layer (Peak 3), and (200) of the A layer An X-ray diffraction result in which each peak with a diffraction peak (peak 4) from the surface is observed is disclosed.

Japanese Patent Laid-Open No. 08-127862 JP 2007-2332 A

  However, in a coating layer obtained by alternately laminating two or more kinds of thin layers, a diffraction peak of each layer is not observed as in Patent Document 1, and a coating layer consisting of only one diffraction peak is used, as in Patent Document 2. Even in the coating layer in which the peaks of the A layer and the B layer are observed, the wear resistance and fracture resistance of the coating layer are not always sufficient, and it is necessary to improve the fracture resistance.

  The present invention is for solving the above-mentioned problems, and an object thereof is to provide a surface-coated tool provided with a coating layer having high wear resistance and fracture resistance.

In the cutting tool of the present invention, MC _1-x N _x (where M is one or more selected from Periodic Tables 4, 5, and 6 elements, rare earth elements, Al and Si, 0.5 ≦ x ≦ 1) and a laminated structure in which two types of layers A and B having a cubic crystal structure are alternately laminated. In the X-ray diffraction (XRD) pattern of Cu—Kα ray at the flank (111) The diffraction peak observed as a plane has three peaks: a peak P _{A (111) of} the A layer, an intermediate peak P _{M (111)} , and a peak P _{B (111)} of the B layer from the low angle side of the diffraction angle 2θ. A coating layer having the strongest peak intensity of the intermediate peak PM ₍₁₁₁₎ of the three peaks is formed.

Here, the diffraction peaks observed as the (200) plane in the XRD pattern on the flank face are the peak P _{A (200)} , the intermediate peak P _{M (200)} , and B of the A layer when the diffraction angle 2θ is from the low angle side. It is desirable that there are three peaks P _{B (200)} of the layer, and the peak intensity of the intermediate peak P _{M (200) in} the three peaks is the strongest.

Further, the peak P _{A (111) of} the A layer, the intermediate peak P _{M (111)} , the peak P _{B (111)} of the B layer observed as the (111) plane in the XRD pattern on the flank The peak intensities are IA ₍₁₁₁₎ , _{IM (111)} , IB ₍₁₁₁₎ , the peak P _{A (200) of} the A layer on the (200) plane, the intermediate peak P _{M (200)} , B When the peak intensities of the layer peaks P _{B (200)} are I _{A (200)} , I _{M (200)} , and I _{B (200)} , respectively, I _{A (111)} / I _{M (111)} = 0.1˜ 0.5, I _B
(111) / _{IM (111)} = 0.1 to 0.6, IA ₍₂₀₀₎ / _{IM (200)} = 0.
2 to 0.8, I _{B (200)} / I _{M (200)} = 0.1 to 0.4, I _{A (111)} / I _{A (200)} = 0.03 to 0.1, I _{M (111 )} / _{IM (200)} = 0.05 to 0.1, and IB ₍₁₁₁₎ / IB ₍₂₀₀₎ = 0.03 to 0.4.

Furthermore, as the (111) plane in the XRD pattern on the rake face, three peaks are observed: the peak p _{A (111)} of the A layer, the intermediate peak p _{M (111)} , and the peak p _{B (111)} of the B layer. , The peak intensities of the peak p _{A (111)} , the intermediate peak p _{M (111)} , and the peak p _{B (111)} of the layer _B are i _{A (111)} , i _{M (111)} , i _{B, respectively. (111)} The three peaks of the A layer peak, the intermediate peak, and the B layer peak are observed as the (200) plane in the XRD pattern on the rake face, and the A layer peak p _{A (200)} When the peak intensities of the intermediate peak p _{M (200)} and the peak p _{B (200)} of the B layer are i _{A (200)} , i _{M (200)} , and i _{B (200)} , respectively, (i _{A (111)} / _{i M 111)) / (I A (} 111) / I M (111)) = 0.7 ~ 0.95, (i
_{B (111)} / i _{M (111)} ) / (IB ₍₁₁₁₎ / _{IM (111)} ) = 0.8-0.
A ratio of 9 is desirable.

  According to the cutting tool of the present invention, there are three (111) diffraction peaks in the X-ray diffraction of Cu—Kα rays on the flank in the coating layer in which two types of layers A and B are alternately laminated. And the intermediate peak of the three peaks has the strongest intensity, so that the stress remaining in the coating layer is optimized, and the peeling of the coating layer can be suppressed, resulting in high fracture resistance and wear resistance. It turns out that the nature becomes high.

It is the (a) schematic perspective view which shows an example of the surface covering cutting tool which is a suitable example of the cutting tool of this invention, (b) The schematic diagram which shows the structure of a coating layer. It is a X-ray diffraction (XRD) pattern of the coating layer in the cutting tool of FIG.

  FIG. 1 is a schematic perspective view of a throw-away insert which is a preferred embodiment example of the cutting tool of the present invention, FIG. 1B is a schematic perspective view for explaining the configuration of the coating layer, and the coating layer. 2 is an X-ray diffraction (XRD) pattern of Cu-Kα rays in FIG. In FIG. 2, as reference materials, (a) an XRD pattern on the flank face of the coating layer formed only by the A layer, and (b) an flank face of the coating layer formed only by the B layer. An XRD pattern is also shown.

According to FIG. 1 (a), a throw-away insert (hereinafter simply referred to as an insert) 1 of the present invention includes a rake face 3 on a main surface, a flank face 4 on a side face, a rake face 3 and a flank face 4; The cutting edge 5 is provided at the crossing ridge line, and the coating layer 6 is formed on the surface of the substrate 2.

As shown in FIG. 1B, the covering layer 6 has a laminated structure in which an A layer 7 and a B layer 8 are laminated together, and both the A layer 7 and the B layer 8 are MC _1-x N _x (however, M is composed of one or more selected from Periodic Tables 4, 5, and 6 elements, rare earth elements, Al and Si, and 0.5 ≦ x ≦ 1) and a structure having a cubic crystal structure. As shown in the XRD pattern on the flank 4 of the insert 1 in FIG. 2, the diffraction angle 2θ is A from the low angle side as a diffraction peak of the (111) plane observed at a diffraction angle 2θ = 36 to 40 °. There are three peaks, the peak P _{A (111)} , the intermediate peak P _{M (111) of} the layer 7, and the peak P _{B (111)} of the B layer 8, and of these three peaks, the intermediate peak P _{M ( 111)} has the strongest peak intensity.

  Thereby, the residual stress applied to the coating layer 6 can be optimized, chipping when used as a cutting tool can be suppressed, and wear resistance is improved. That is, in the XRD pattern of the covering layer having a laminated structure composed of mutually laminated layers, when the diffraction peak of the (111) plane consists of only one, the residual stress is too high and the wear resistance is reduced although the wear resistance is high. . In addition, when the diffraction peak consists of only two peaks of each of the A layer and the B layer, the residual stress is low and both wear resistance and fracture resistance are lowered.

Here, as shown in the XRD pattern on the flank 4 of the insert 1 in FIG. 2, the diffraction angle 2θ of the diffraction peak of the (200) plane observed at the diffraction angle 2θ = 42 to 46 ° of the coating layer 6 is also low. From the angle side, there are three peaks, the peak P _{A (200) of} the A layer 7, the intermediate peak P _{M (200)} , and the peak P _{B (200)} of the B layer 8. It is desirable that the peak intensity of _{M (200)} is the strongest.

In addition, the peak intensity of the peak P _{A (111)} , the intermediate peak P _{M (111)} of the A layer 7 on the (111) plane in the XRD pattern on the flank 4 and the peak P _{B (111)} of the B layer 8 are represented by I _{A (111)} , I _{M (111)} , I _{B (111)} , the peak P _{A (200) of} the A layer on the (200) plane, the intermediate peak P _{M (200)} , the peak P _{B of the} B layer _When the peak intensities of ₍₂₀₀₎ are I _{A (200)} , I _{M (200)} , and I _{B (200)} , respectively, I _{A (111)} / I _{M (111)} = 0.1 to 0.5, I _{B (111)} / _{IM (111)} =
From the ratio of 0.1 to 0.6, I _{A (200)} / I _{M (200)} = 0.2 to 0.8, I _{B (200)} / I _{M (200)} = 0.1 to 0.4 Is desirable in terms of improving wear resistance,
Further, I _{A (111)} / I _{A (200)} = 0.03 to 0.1, I _{M (111)} / I _M
(200) = 0.05 to 0.1 and IB ₍₁₁₁₎ / IB ₍₂₀₀₎ = 0.03 to 0.4 are desirable from the viewpoint of improving fracture resistance.

Further, the peak observed as the (111) plane in the XRD pattern on the rake face 3 is also the peak p _{A (111)} , intermediate peak p _{M (111)} , and B layer of the A layer 7 from the diffraction angle 2θ of the low angle side. There are three peaks pB ₍₁₁₁₎ of 8 and when the peak intensities of each peak are iA ₍₁₁₁₎ , iM ₍₁₁₁₎ , iB ₍₁₁₁₎ , (iA _{(111 )} / I _{M (111)} ) / (I _{A (111)} / I _{M (111)} ) = 0.7-0.95, (i _{B (
111)} / i _{M (111)} ) / (IB ₍₁₁₁₎ / _{IM (111)} ) = 0.8 to 0.9 in terms of improving wear resistance and fracture resistance desirable.

  The factors that determine the peak intensity include the film thickness, crystallinity, and orientation of the A layer and the B layer, and can be achieved by controlling the film forming conditions described later.

Here, the ratio of the average layer thickness t ₁ of each one layer of the A layer 7 to the average layer thickness t ₂ of each one layer of the B layer 8 is 0.7 ≦ t ₂ / t ₁ ≦ 2. Therefore, the coating layer 6 is not peeled off and the chipping resistance is high, and the wear resistance on the surface of the coating layer 6 is high. If the average layer thickness of each of the A layer 7 and the B layer 8 is 1 nm or more, the effect of the laminated structure is remarkably exhibited, and if it is 200 nm or less, a hardness improvement effect can be expected. Further, the average layer thickness t ₁ of the A layer 7 is ₁₀ to 20 nm and the average layer thickness t ₂ of the B layer 8 is 12 to 45 nm, thereby increasing the hardness of the coating layer 6 and improving the wear resistance of the coating layer 6. It is desirable in that it can be improved. Incidentally, the desired thickness of each layer, the average layer thickness _{t 1} of the A layer 7 13～16Nm, average layer thickness _{t 2} of the B layer 8 is 15 to 30 nm.

  The overall average layer thickness of the coating layer 6 is 0.8 to 10 μm. With this layer thickness, the wear resistance of the tool 1 is high, the internal stress of the coating layer 6 is not excessively increased, and the fracture resistance of the coating layer 6 is not lowered. A desirable overall average layer thickness of the covering layer 6 is 1 to 6 μm.

  Here, the covering layer 6 is formed with columnar crystals (not shown) extending in the perpendicular direction in the direction perpendicular to the laminated surface of the A layer 7 and the B layer 8 and adjacent thereto. It is desirable that the laminated surface of the A layer 7 and the B layer 8 is continuously epitaxially grown at the interface between the two existing columnar crystals. Thereby, the effect of reducing the influence of stacking faults that promote the progress of cracks is high, and the chipping resistance of the coating layer 6 can be enhanced. In the present invention, a crystal specified by a crystal whose crystal length in a direction perpendicular to the surface of the substrate 2 is 1.5 times longer than a crystal width in a direction parallel to the surface of the substrate 2 is defined as a columnar crystal. And the toughness of the tool 1 can further be improved by the coating layer 6 being comprised with a columnar crystal.

  On the other hand, when the average crystal width of the columnar crystals (grain size in the direction of the layered surface of the A layer 7 and the B layer 8) is 0.05 μm or more, the oxidation resistance of the coating layer 6 does not decrease, whereas the columnar crystals When the average crystal width of the crystals is 0.3 μm or less, the hardness and fracture resistance of the coating layer 6 are high. A desirable range of the average crystal width of the coating layer 6 is 0.1 to 0.2 μm. In the present invention, the average crystal width of the coating layer 6 is measured by drawing a line A (not shown) at a portion corresponding to the intermediate thickness of the coating layer 6 in the cross-sectional photograph of the coating layer 6. To do. Specifically, the average crystal width of the columnar crystals in the covering layer 6 specifies a length L (not shown) of the line A of 100 nm or more, and the number of grain boundaries crossing the line A having this length L is determined. Count and calculate by length L / number of grain boundaries.

  Further, in the overall composition of the coating layer 6, it is desirable that the metal element M includes Ti and Al having particularly high hardness, and additionally includes at least one of Nb, Mo, Ta, W, Cr, and Si. It is desirable. The composition of each of the A layer 7 and the B layer 8 is composed of cubic crystals, but it is not always necessary that both layers contain Ti and Al.

Further, as the substrate 2, a cemented carbide or a cermet hard alloy comprising a hard phase mainly composed of tungsten carbide or titanium carbonitride and a binder phase mainly composed of an iron group metal such as cobalt or nickel, silicon nitride, or the like. Hard materials such as ultra-high pressure sintered bodies that fire ceramics and aluminum oxide as a main component, hard phases composed of polycrystalline diamond and cubic boron nitride and binder phases such as ceramics and iron group metals under ultra-high pressure Preferably used.
(Production method)
Next, the manufacturing method of the cutting tool of this invention is demonstrated. First, the tool-shaped substrate 2 is manufactured using a conventionally known method. Next, the coating layer 6 is formed on the surface of the substrate 2. A physical vapor deposition (PVD) method such as an ion plating method can be suitably applied as a method for forming the coating layer 6.

As a specific example, a gas such as N ₂ or Ar is introduced into a vacuum chamber of an AIP apparatus from a gas inlet, and a cathode electrode and an anode electrode are disposed at, for example, opposing positions on the inner surface of the vacuum chamber. Then, a high voltage is applied between the two to generate plasma, and the plasma evaporates a desired metal or ceramic from the target and ionizes it into a high energy state, and this ionized metal is applied to the sample (substrate 2). The structure is such that the coating layer 6 is coated on the surface of the substrate 2 by being attached to the surface. In addition, the substrate is set on the tower, and a plurality of substrates are placed on the sample support table, and the sample support table is mounted on a table on which a plurality of sample support tables are arranged. Further, the AIP apparatus is provided with a heater for heating the substrate 2, a gas discharge port for discharging gas out of the system, and a bias power source for applying a bias voltage to the substrate 2.

  As the target, for example, a metal target containing metal M (wherein M is one or more elements selected from Group 4, 5, 6 elements, Al, rare earth elements and Si) independently, A composite alloy target, a mixture target made of these carbide, nitride, boride compound powder, or sintered body can be used.

Then, using a target, the metal source is evaporated and ionized by arc discharge, glow discharge, or the like, and at the same time, nitrogen (N ₂ ) gas as a nitrogen source or methane (CH ₄ ) / acetylene (C ₂ H ₂ ) gas as a carbon source. As a result, the coating layer 6 is deposited on the surface of the substrate 2.

Further, when film formation, when the cycle consisting in a direction closest to the target at each position of the group member 2 and the rotational speed of the sample, so that the rotation speed becomes the period of 2~6rpm substrate 2 and the sample support It is desirable to adjust the rotation speed of the table.

  Here, in the present invention, when the substrate 2 is arranged in the direction facing the target and facing it, the metal component from the target will fly linearly, and the concentration of the gas introduced into the chamber Since the gas pressure is low depending on the distribution, the metal is deposited in a form in which more metal is deposited than non-metal. On the other hand, when the substrate 2 is away from the target and is not opposed to the position, the deposited metal component is deposited and deposited, so that the deposition amount of the metal component is reduced. In addition, since the nonmetallic component gas is introduced from the center of the sample stage, the concentration of the gas increases as the base 2 moves away from the target 25, and the nonmetal is deposited in a form in which more metal is deposited than the metal.

  The sample support table on which the substrate 2 is placed is formed while the table rotates while the tower rotates, so that each sample support table rotates, and a plurality of sample support tables revolve. According to the present invention, the rotation timing is discontinuous, and the time for the base 2 to be disposed in the direction facing the target and facing the target is adjusted to the time for the base 2 to be disposed away from the target. Thus, the layer thicknesses of the A layer 7 and the B layer 8 can be controlled.

In order to generate plasma, arc discharge, glow discharge, or the like is used, and nitrogen (N ₂ ) gas as a nitrogen source or methane (CH ₄ ) / acetylene (C ₂ H ₂ ) gas as a carbon source is used as an introduction gas. be able to. Further, the bias voltage at the time of film formation is set to 50 to 200 V at the initial stage of film formation in order to produce a highly hard coating layer 6 in consideration of the crystal structure of the coating layer and to improve the adhesion to the substrate 2. It is desirable. In the configuration of the present invention, the XRD peak of the coating layer can be set within a predetermined range by applying a respective arc current to each target and making a difference in the heater temperature near each target.

Mainly composed of tungsten carbide (WC) powder having an average particle diameter of 0.8 μm, 10% by mass of metallic cobalt (Co) powder having an average particle diameter of 1.5 μm, and vanadium carbide (VC) powder having an average particle diameter of 1.5 μm. Chromium carbide (Cr ₃ C ₂ ) powder having an average particle diameter of 0.1 μm and an average particle size of 1.5 μm is added and mixed at a ratio of 0.3% by mass, and after forming into a throw-away tip shape by press molding, the removal is performed. Binder treatment was performed and fired at 1450 ° C. for 1 hour in a vacuum of 0.01 Pa to produce a cemented carbide. Further, the rake face surface of each sample was polished by blasting, brushing or the like. Further, the prepared cemented carbide was subjected to blade edge processing (honing) by brushing.

  Coating layers having various compositions shown in Table 1 were formed on the substrate thus prepared by arc ion plating. With respect to the obtained sample, the cross section including the surface of the coating layer was observed with a transmission electron microscope (TEM), and the average crystal width of the crystals constituting the coating layer was determined. Moreover, when observing with TEM, the composition in arbitrary three places of each coating layer was measured by energy dispersive spectroscopy (EDS), and these average values were computed as a composition of each coating layer.

Next, a cutting test was performed under the following cutting conditions using the obtained throw-away tip (model number: BDMT11T304-JT manufactured by Kyocera). The results are shown in Table 3.
Cutting method: Milling shoulder processing material: SKD11
Cutting speed Vc: 120 m / minute feed fz: 0.12 mm / blade cutting: ap 2.0 mm × ae 12.5 mm
Cutting state: Dry evaluation method: The presence or absence of lateral flank wear, boundary damage, and chipping (including chipping) after cutting for 25 minutes was measured with a microscope.

From the results shown in Tables 1 to 3, sample Nos. A and B have the same arc current value. 7. Sample No. with sample rotation speed exceeding 6 rpm / second 8, the target temperature of the A layer and the B layer is 550 ° C. and the same sample No. 10, only one diffraction peak was observed as the (111) plane in the XRD pattern on the flank, and defects were generated. In addition, when the target temperature of the A layer and the B layer is 550 ° C., the same sample No. In No. 9, the number of diffraction peaks observed as the (111) plane in the XRD pattern on the flank surface was two, and the wear resistance decreased.

  On the other hand, sample No. which is within the scope of the present invention. In all of Nos. 1 to 6, the coating layer was excellent in fracture resistance and oxidation resistance and exhibited good cutting performance.

1 Throw away insert (insert)
2 substrate 3 rake face 4 flank face 5 cutting edge 6 coating layer 7 A layer 8 B layer PA Of the three diffraction peaks observed as the (111) plane in the XRD pattern on the flank face of the ₍₁₁₁₎ insert in flank of a peak P _{B (111)} insert appearing in the middle of the three diffraction peaks observed as (111) plane in the XRD pattern at flank of the peak P _{M (111)} insert appearing in the lingering diffraction angle three being observed as (200) plane in the XRD pattern at the peak P _{a (200)} flank the insert appearing in the high diffraction angles of the three diffraction peaks observed as (111) plane in the XRD pattern as (200) plane in the XRD pattern at the peak P _{M (200)} flank the insert appearing in the lingering diffraction angle of the diffraction peaks of Appearing in the high diffraction angles of the three diffraction peaks observed as (200) plane in the XRD pattern at flank of a peak P B ₍₂₀₀₎ insert appearing in the middle of the three diffraction peak measured peak

Claims (4)

On the surface of the substrate, MC _1-x N _x (where M is one or more selected from Periodic Tables 4, 5, and 6 elements, rare earth elements, Al and Si, 0.5 ≦ x ≦ 1) Diffraction peak observed as (111) plane in the X-ray diffraction (XRD) pattern of Cu-Kα ray at the flank face, consisting of a laminated structure in which two types of layers A and B having a cubic crystal structure are alternately laminated. Has a peak of the A layer, an intermediate peak, and a peak of the B layer from the low angle side of the diffraction angle 2θ, and forms a coating layer having the strongest peak intensity of the intermediate peak of the three peaks. Cutting tool.   The diffraction peak observed as the (200) plane in the XRD pattern on the flank has three peaks, the diffraction angle 2θ from the low angle side, the peak of the A layer, the intermediate peak, and the peak of the B layer, The cutting tool according to claim 1, wherein the peak intensity of the intermediate peak among the three peaks is the strongest. The peak intensity of the peak of the A layer, the intermediate peak, and the peak of the B layer observed as the (111) plane in the XRD pattern on the flank are respectively IA ₍₁₁₁₎ , _{IM (111)} , I The peak intensities of the peak of the A layer, the intermediate peak, and the peak of the B layer on the _{B (111)} and (200) planes were defined as IA ₍₂₀₀₎ , _{IM (200)} , and IB ₍₂₀₀₎ , respectively. IA ₍₁₁₁₎ / _{IM (111)} = 0.1 to 0.5, IB _{(111)
/ I M (111) = 0.1} ~ 0.6, I A (200) / I M (200) = 0.2 ~ 0.8, I B (200) / I M (200) = 0.1 ~ 0.4, IA ₍₁₁₁₎ / IA ₍₂₀₀₎ =
0.03 to 0.1, I _{M (111)} / I _{M (200)} = 0.05 to 0.1, I _{B (111)} / I _{B (200)} = 0.03 to 0.4 Item 3. The cutting tool according to Item 2. The diffraction peak observed as the (111) plane in the X-ray diffraction (XRD) pattern of Cu-Kα ray at the rake face is the peak of the A layer, the intermediate peak, and the peak of the B layer from the diffraction angle 2θ from the low angle side. There are three peaks, and the peak intensities of the A layer, the intermediate peak, and the B layer on the (111) plane are i _{A (111)} , i _{M (111)} , i _{B (111 )} (I _{A (111)} / i _{M (111)} ) / (IA ₍₁₁₁₎ / _{IM (111)} ) = 0.7 to 0.95, (i _{B (111)} / i _{M (111)} ) / (IB ₍₁₁₁₎
The cutting tool according to any one of claims 1 to 3, comprising a ratio of / I _{M (111)} ) = 0.8 to 0.9.

Images