JPH0343105A - Surface filmed cutting tool made of tungsten carbide based superalloy - Google Patents

Abstract

PURPOSE:To suppress peeling at the time of cutting by forming a carbon film containing specific weight % of either or both of titanium boride and titanium nitride and having crystal structure in, at least, a portion on the surface of a tungsten carbide radial superalloy base substance. CONSTITUTION:A surface filmed cutting tool made of tungsten carbide radical superalloy is manufactured by forming a hard film layer made of diamond crystal structure film, or a carbon film having diamond crystal structure in, at least, a portion, and containing 10ppm-10weight% of titanium boride and/or titanium nitride in either films on the surface of a tungsten carbide radial superalloy base substance. Thus, since not only peeling of the hard film layer is nil while cutting is performed, but also the hard film layer retains relatively high hardness, it shows excellent wear resistance, and excellent cutting performance can be obtained for a remarkably long period of time.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is particularly applicable to A11, A, and 9 alloys, as well as Cu and C
Regarding a surface-coated tungsten carbide (hereinafter referred to as WC) cemented carbide cutting tool that exhibits excellent cutting performance over a long period of time without causing peeling of the hard coating layer when used for cutting U-alloy, etc. It is something.

[Conventional technology]

Conventionally, for the purpose of improving wear resistance, the surface of a WCC cemented carbide substrate has been coated with the hot filament method described in, for example, JP-A-58-91100, or JP-A-58-11049.
A surface wave of more than 1wc is obtained by forming a hard coating layer made of a diamond crystal structure film with an average layer thickness of 1 to 20 cm using a vapor phase synthesis method such as the microwave non-polar discharge method described in Publication No. 49. Attempts have been made to use cutting tools made of hard alloys, particularly for cutting Afi and A1 alloys, as well as Cu and Cu alloys.

[Problem to be solved by the invention]

However, in the above-mentioned conventional surface-coated WCC cemented carbide cutting tool, the linear expansion coefficient of the diamond crystal structure film constituting it is 1.18X 10'/'C; Hard metal substrate that is 2~4 x 10-6
Since there is a large difference in coefficient of linear expansion between the two, the hard coating layer tends to peel off due to the high temperature heating caused by the heat generated during cutting, and it is currently difficult to put it into practical use. be.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors focused on the conventional surface-coated WCC cemented carbide cutting tool and conducted research to suppress the peeling of the hard coating layer that constitutes it during cutting. As a result, when using the above-mentioned known vapor phase synthesis method to form a hard coating layer consisting of a diamond crystal structure film on the surface of a WCC cemented carbide substrate, for example, if a hot filament method is used, the reaction mixture gas is Titanium boride (hereinafter referred to as TiB2) and/or titanium nitride (TiB2) is added to the hard coating layer formed on the substrate surface by mixing N2 gas or by irradiating the substrate surface with TI ions or B ions from an ion gun. When TiN (hereinafter referred to as TiN) is dispersed, the linear expansion coefficient of the hard coating layer increases as the content of these components increases, and the difference in linear expansion coefficient between it and the base material decreases. The coating layer will no longer peel off due to heat generation during cutting, and in this case, the hard coating layer will have a diamond crystal structure as a whole in areas where the content of the dispersed component is small, similar to the conventional hard coating layer. As the content of the dispersed components increases, the diamond crystal structure gradually decreases, but if even a part of the diamond crystal structure remains in the hard coating layer, there is no significant decrease in hardness and it has excellent durability. They obtained the knowledge that wear resistance can be ensured.

The present invention has been made based on the above findings, and includes a diamond crystal structure film, or a carbon film at least partially having a diamond crystal structure, on the surface of a WCC cemented carbide substrate, and any of the above films. , T iB
The present invention is characterized by a surface-coated WCC cemented carbide cutting tool formed by forming a hard coating layer containing LOppm-10% by weight of TiC and/or TiC.

In addition, in the cutting tool of the present invention, the content of TiB2 and TiN is limited to 10 ppm-10% by weight in order to prevent the linear expansion coefficient of the hard coating layer from peeling off during cutting if the content is less than 10 ppm. On the other hand, if the content exceeds 10% by weight, it will not be possible to ensure a high hardness of 4000 or more in Vickers hardness (Hv) in the hard coating layer. This is based on the reason that wear resistance decreases.

〔Example〕

Next, the cutting tool of the present invention will be specifically explained using examples.

WCC cemented carbide substrate, 2 as shown in Table 1
It has different compositions, and its shape is ISO/S.
A throw-away tip with a shape specified in PGN 120308 was prepared, and a heat filament method was used to coat the surface of this substrate, reaction vessel: quartz bone with an outer diameter of 120 mmφ, reaction mixture gas composition: CH4 by volume ratio. /H2-5/+000, or CH4/H2/N2-5/+000/1~10, Distance between tungsten filament and substrate surface: 35 degrees, Atmospheric pressure inside reaction vessel 1 torr, Filament temperature: 2000℃, Depends on filament By performing vapor phase synthesis under the following conditions: substrate surface heating temperature = 850 ° C., two predetermined amounts of TI ions and/or B ions as the ejection components of the ion gun, and by forming a hard coating layer as shown in Table 1. Surface coating W of the present invention
Cutting tools 1 to 12 made of C-based cemented carbide (hereinafter referred to as the coated cutting tools of the present invention) and comparative cutting tools 1 to 4 made of surface-wave 51WC-based cemented carbide (hereinafter referred to as comparative coated cutting tools) were manufactured, respectively.

Note that the comparative coated cutting tools 1 and 3 had T r in the hard coating layer.
Comparative coated cutting tools 2 and 4 correspond to conventional coated cutting tools that do not contain B2 and TiN, while comparative coated cutting tools 2 and 4
The contents of T iB 2 and TiN are higher than the range of this invention.

Moreover, the presence or absence of a diamond crystal structure in the hard coating layer was determined by Raman spectrum analysis.

Next, regarding the various coated cutters obtained as a result, the following were obtained: Work material: Ajl-5 wt% S1 alloy, Cutting speed: 250 m/a+In, Depth of cut: 1 mm.

A dry continuous cutting test was conducted on an Al1 alloy under the conditions of feed rate: 0.1 mm/blade, and the cutting time until the flank wear width of the cutting edge reached 0.2 mm was measured. These results are shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, the coated cutting tools 1 to 1 of the present invention
2 has a relatively large linear expansion coefficient due to the inclusion of TiB 2 and/or TiN compared to a hard coating layer with a diamond crystal structure that does not contain these, and this linear expansion coefficient Since the size of the WCC cemented carbide increases in the direction approaching it, the hard coating layer does not peel off even when heated due to heat generation during cutting, and exhibits excellent wear resistance. Is it conventional that does not contain TiB 2 or TiN? In the comparative coated cutting tool 1.3, which corresponds to the cutting tool 1, the heat generated during cutting creates a large linear expansion coefficient difference between the base and the hard coating layer, so the hard coating layer changes in a very short time. In comparative coated cutting tools 2 and 4, in which peeling occurs and subsequent cutting becomes impossible, and the contents of T iB 2 and TtN are higher than the scope of this invention, peeling does not occur in the hard coating layer. However, it is clear that the wear resistance is very poor and the cutting life is relatively short.

As mentioned above, the surface wave l! of this invention! A cutting tool made of WC-based cemented carbide not only has a hard coating layer that does not peel off during cutting, but also has a hard coating layer that is made of a diamond crystal structure film or at least a portion of which has a diamond crystal structure. Since it is made of carbon film and maintains relatively high hardness, it exhibits excellent wear resistance and extremely long-term cutting performance.

Claims (1)

[Claims] (1) The surface of the tungsten carbide-based cemented carbide substrate is composed of a diamond crystal structure film or a carbon film at least partially having a diamond crystal structure, and any of the above films is made of either titanium boride or titanium nitride. A surface-coated tungsten carbide-based cemented carbide cutting tool formed by forming a hard coating layer containing 10 ppm to 10% by weight of either or both.