JPH05162007A - Throw away cutting tip made of artificial diamond-covered tungsten carbide base cemented carbide - Google Patents

Abstract

PURPOSE:To restrain an artificial diamond covered layer which constitutes an artificial diamond covered cemented carbide cutting tip from peeling off out of a base substance. CONSTITUTION:For the thickness of an artificial diamond covered layer formed at the surface of WC base cemented carbide base substance by means of a vapor phase composite method, an corner part in the cutting face of a cutting edge is made a standard thickness, and the other parts including at least a chip contact part is made relatively thicker than the standard thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial diamond coating for suppressing peeling of an artificial diamond coating layer formed by a vapor phase synthesis method from a tungsten carbide (hereinafter referred to as WC) based cemented carbide substrate in practical use. The present invention relates to a WC-based cemented carbide throwaway cutting tip.

[0002]

2. Description of the Related Art Conventionally, generally, for example, JP-A-61-252.
As described in Japanese Patent No. 363, No. 363, the thermoelectron emission method described in Japanese Patent Laid-Open No. 58-91100 and the micro-method described in Japanese Patent Laid-Open No. 58-110494 are formed on the surface of a WC-based cemented carbide substrate. Wave method, and further, JP-A-58-135117
Artificial diamond-coated WC-based cemented carbide slow-away cutting tip (hereinafter Artificial diamond coated carbide cutting tips) are known.

[0003]

On the other hand, the demand for labor saving in cutting in recent years is strict, and along with this, the working conditions of the cutting tool tend to be more severe. In coated carbide cutting tips, when this is used for heavy cutting such as high feed and high cutting, the impact of cutting chips on the rake face of the cutting edge is large,
In addition to the fact that the adhesion of the artificial diamond coating layer to the substrate is not always satisfactory, the current situation is that peeling is likely to occur especially on the chip contact portion of the rake face and only a relatively short service life is exhibited. Is.

[0004]

Therefore, the present inventors have
From the above viewpoints, as a result of research to solve the problems of the conventional artificial diamond-coated carbide cutting tips, the artificial diamond coating of the cutting edge rake face of the artificial diamond-coated carbide cutting tips Artificial part of other part including at least a chip contact part, that is, a part where the plane shape is concentric circles or crosses in a practical state, with the layer thickness being 2 to 20 μm which is a normal standard thickness. The thickness of the diamond coating layer is relatively thicker than the standard thickness,
Desirably, when the thickness is 4 to 50 μm, the mechanical impact due to the chips is mitigated by this thick portion, and the thermal shock caused by the difference in thermal expansion between the substrate and the artificial diamond coating layer is also suppressed. Therefore, the research results that the peeling of the artificial diamond coating layer during heavy cutting is remarkably suppressed were obtained.

The present invention has been made based on the above-mentioned research results.
In an artificial diamond-coated carbide cutting tip formed by forming an artificial diamond coating layer by a vapor phase synthesis method, the thickness of the artificial diamond coating layer is a standard thickness of 2 to 20 μm at the corners of the rake face of the cutting edge, The other part including at least the chip contacting part, that is, practically, FIG.
As shown in the schematic perspective view in FIG. 4, a flat concentric circular or cross-shaped portion has a wall thickness 4 which is relatively thicker than the standard thickness.
It is characterized by the artificial diamond-coated carbide cutting tip having a thickness of ˜50 μm.

In the artificial diamond-coated carbide cutting tip of the present invention, the artificial diamond coating layer at the corner of the rake face has a standard thickness of 2 to 20 μm.
This is because if the thickness is less than 2 μm, the desired effect of improving the wear resistance due to the artificial diamond coating layer cannot be obtained, and if the thickness exceeds 20 μm, chipping is likely to occur. Part thickness 4-5
When the thickness of the corner is 2 μm, which is the minimum, the thickness of 4 μm is required at least in order to exert the desired artificial diamond coating layer peeling suppression effect, while the thickness is 50 μm. If it exceeds, not only does it take a long time to form it, but also cracks and chips easily occur.

[0007]

EXAMPLES Next, the artificial diamond-coated cemented carbide cutting tip of the present invention will be specifically described by way of examples. As the substrate, the composition shown in Table 1 and SPGN12030
Prepare a WC-based cemented carbide throwaway cutting tip having the shape of 8, and first use the microwave method for the cutting edge rake face (upper face) and flank face (side face) of this tip, and the reaction gas composition: flow rate CH ₄ / H ₂ = ratio (cc / min)
8/1000, atmospheric pressure: 20 torr, microwave output: frequency 2.45 GHz-500 W, the treatment time was adjusted, and artificial diamond coating layers of various thicknesses (corner thicknesses) shown in Table 1 are also shown. Is uniformly formed and is used as a conventional artificial diamond-coated carbide cutting tip (hereinafter referred to as a conventional coating cutting tip) 1 to 5, and subsequently, when the planar shape of the thick portion is the same circle, Place a Ti ring-shaped cover plate of a shape that covers the corners of the rake face and exposes the center of the chip on the chip, and in the case of forming the same cross shape, Ti at the four corners of the chip.
The artificial diamond-coated cemented carbide of the present invention is formed by again forming the artificial diamond coating layer under the above-mentioned conditions with the plate-shaped fan-shaped corner sack inserted and forming a thick portion having the thickness shown in Table 1. Cutting chips (hereinafter referred to as the coated cutting chips of the present invention) 1 to 5 were manufactured.

[0008]

[Table 1]

Then, with respect to various coated cutting chips obtained as a result, a work material: a round bar of Al-12 wt% Si alloy, cutting speed: 300 m / min., Feed: 0.3 mm / rev., Cutting : 3 mm, cutting time: 30 min., A wet high-cut continuous cutting test of an Al alloy was performed, and the state of peeling of the artificial diamond coating layer on the rake face of the cutting edge was observed. The results are shown in Table 1.

[0010]

From the results shown in Table 1, in the coated cutting chips 1 to 5 of the present invention, since the thick portion is formed on the rake face of the artificial diamond coating layer, the conventional coated cutting without the formation thereof is shown. It is clear that the peeling resistance of the artificial diamond coating layer is remarkably improved as compared with the chips 1 to 5, and no peeling occurs in the artificial diamond coating layer even when cutting under severe conditions.

As described above, in the artificial diamond-coated carbide cutting tip of the present invention, the thick portion of the artificial diamond coating layer formed on the rake face of the cutting edge is caused by the difference in thermal expansion between the substrate and the artificial diamond coating layer. Since it alleviates the thermal shock of and the mechanical shock at the time of cutting by cutting chips, the occurrence of peeling of the artificial diamond coating layer can be significantly suppressed even when cutting under severe conditions such as heavy cutting, It exhibits excellent cutting performance over a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic perspective view illustrating an artificial diamond-coated carbide cutting tip of the present invention.

Claims (4)

[Claims] 1. An artificial diamond-coated tungsten carbide-based cemented carbide slow-away cutting tip, comprising an artificial diamond coating layer formed on a surface of a tungsten carbide-based cemented carbide substrate by a vapor phase synthesis method. The thickness of the layer, the corner portion in the rake face of the cutting edge is a standard thickness, other portions including at least the chip contact portion is made relatively thicker than the standard thickness, an artificial diamond characterized by the following: Throwaway cutting tip made of coated tungsten carbide based cemented carbide. 2. The artificial diamond-coated tungsten carbide-based cemented carbide throwaway according to claim 1, wherein the planer shape of the thick portion of the artificial diamond coating layer on the rake face of the cutting edge is concentric circles. Cutting tip. 3. The artificial diamond-coated tungsten carbide-based cemented carbide throwaway according to claim 1, wherein the planer shape of the thick portion of the artificial diamond coating layer on the rake face of the cutting edge is a cross shape. Cutting tip. 4. The thickness of the corner portion of the artificial diamond coating layer on the rake face of the cutting edge is 2 to 20 μm, and the thickness of the thick portion is 4 to 50 μm. An artificial diamond-coated tungsten carbide-based cemented carbide throwaway cutting tip according to item 2 or item 3.