JPS6389202A - Surface coated hard super alloy cutting tool showing stable service life - Google Patents

Abstract

PURPOSE:To improve the wear and fracture resistance of a tool and stabilize the service life thereof by coating a WC base super alloy parent material or TiCN base cermet parent material in such a way that one or more types of TiC, TiN and TiCN are used as an inner layer and alpha type Al2O3 as an outer layer under a proper condition. CONSTITUTION:A cutting tool element is prepared as a WC base super alloy parent material, composed, for example, of 72% WC, 8% TiC, 10% TaC and 10% Co by wt%. Then, ambient pressure, temperature and a condition for a reaction gas composition and a flow ratio and the like are adjusted to predetermined values, using an ordinary chemical vapor deposition device and a hard layer comprising inner and outer layers is formed on the surface of said element. And the inner layer is made from TiC, TiN and TiCN showing a maximum peak of (200) faces with X-ray diffraction and the outer layer from alphatype Al2O3, thereby enabling improving and stabilizing the wear and fracture resistance of the tool, and extending the exchange time thereof.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a surface-coated hard alloy cutting tool that not only exhibits excellent wear resistance and chipping resistance but also has an extremely stable service life. .

[Conventional technology]

Ti carbides, nitrides, and carbonitrides such as TiC, TiN, TiC, TiN, Ti carbide, nitride, and carbonitride C, respectively, are applied to the surface of the tungsten carbide C (hereinafter referred to as WC) base cemented carbide base material or the titanium carbonitride C (hereinafter referred to as T1CN) base cermet base material. and T1CN)
A surface coating consisting of a hard surface layer consisting of an inner layer consisting of a single layer or a multilayer of two or more types of the above, and an outer layer consisting of aluminum oxide (hereinafter referred to as A/203). Hard metal cutting tools (hereinafter referred to as surface-coated cutting tools) are known.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional surface-coated cutting tools have large variations in their service life, and therefore, when changing tools based on cutting constants, the lower limit of the variation must be taken into consideration, and overall usage times should be shortened. Currently, tools are set to be replaced, which is not economical.

[Means for solving problems]

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to suppress the variation in the service life of the above-mentioned surface-coated cutting tools, thereby extending the service life overall. According to X-ray diffraction analysis of the surface hard layer of a surface-coated cutting tool, it was found that the highest peak of the inner layer shows a (220) plane in most cases, and the outer layer shows a mixed structure of α-type and α-type. However, by adjusting the conditions such as the atmospheric pressure, temperature, and the composition and flow rate of the reaction gas in the chemical vapor deposition apparatus, the inner layer of the hard surface layer was determined to have a maximum peak of (200) in X-ray diffraction.
Consisting of TiC, TiN, and T1CN showing surfaces,
In addition, when the outer layer is made of α-type Al2O3, not only the wear resistance and chipping resistance are relatively improved, but also the variation in the service life of the same type of tool is significantly suppressed, and constant cutting is achieved. This led to the discovery that the lifespan of tool replacement can be extended.

The present invention was made based on the above findings, and includes a single layer or two layers of one of TiC, TiN, and T1CN on the surface of a WCC cemented carbide base material or a T1CN-based cermet base material. Consisting of multiple layers of seeds or more, and
It is coated with a hard surface layer consisting of an inner layer whose highest peak shows the (200) plane in line diffraction and an outer layer made of α-type Al2O3, and has excellent wear resistance and chipping resistance, and is stable. The surface-coated cutting tool is characterized by a long service life.

〔Example〕

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

Example I WCC cemented carbide matrix, manufactured by conventional powder metallurgy method, 72%WC-8%TiC-10%Ta by weight%
C-10%Co set E (similar to ISO classification p30), and cutting tool material with the shape of SNMN432, and Ti CNN sacer-knot base material, also produced by the usual powder metallurgy method. In weight percent, 50% TiCN-15
%WC-S%TaC-10%Mo2C5%Ni-12%
C.

A cutting tool material having a composition of By forming a surface hard layer with an average layer thickness, the surface-coated cutting tools 1 to 4 of the present invention
and conventional surface-coated cutting tools 1 to 4 were manufactured, respectively.

Next, regarding the surface-coated cutting tools 1 to 3 of the present invention and the conventional surface-coated cutting tools 1 to 3, the number of test pieces was 10, Work material: SNCM439 (hardness: HB230) round bar, Cutting speed variation: 160 m /order.

Sending: Q, 3W/reV,.

Depth of cut = 2. , Cutting time: 3011!111, A cutting test was conducted under the following conditions, and the flank wear width of the cutting edge was measured to evaluate the variation in wear resistance, and the work material: S
Grooved round bar of NCM439 (hardness: HB270).

Cutting speed: 140m/mi.

Feed: 0.25 +s/rev, depth of cut = 1.
A cutting test was conducted under the following conditions, and the cutting time until fracture occurred on the cutting edge was measured, and the variation in fracture resistance was evaluated.

In addition, regarding the surface-coated cutting tool 4 of the present invention and the conventional surface-coated cutting tool 4, the number of test pieces was 10, rigid material: round bar of SCM415 (hardness: HB140), cutting speed: 200 m/de, feed. : 0.2 w/rev,, Depth of cut: 1■.

A cutting test was conducted under the conditions of cutting time = 45-1, and the flank wear width of the cutting edge was measured to evaluate the variation in wear resistance.
M415 (hardness: HB415) square material, cutting speed: 18
0m/m.

Forward 20, 2nd key/rev,.

Depth of cut: 1.5m.

Cutting tests were conducted under the following conditions, the cutting time until fracture occurred on the cutting edge was measured, and the variation in fracture resistance was evaluated.

These results are shown in FIGS. 1 and 2.

〔Effect of the invention〕

From the results shown in FIG. 1 and FIG.
It is clear that, compared to Samples 4 to 4, they exhibit superior wear resistance and chipping resistance, and their variation is significantly smaller.

As mentioned above, the surface-coated cutting tool of the present invention has excellent wear resistance and chipping resistance, and its variation is small, so the life of the cutting tool can be greatly extended in constant cutting. It has industrially useful properties such as:

[Brief explanation of the drawing]

Figure 1 is a diagram showing the flank wear width for every 10 surface-coated cutting tools, and Figure 2 is a diagram showing the cutting time until chipping occurs on every 10 cutting edges of the surface-coated cutting tool. be.

Claims (1)

[Claims] The surface of the tungsten carbide-based cemented carbide base material or titanium carbonitride-based cermet base material is composed of a single layer or a multilayer of two or more of Ti carbides, nitrides, and carbonitrides, and Excellent abrasion and chipping resistance and stable use due to coating with a hard surface layer consisting of an inner layer whose highest peak shows the (200) plane in X-ray diffraction and an outer layer made of α-type aluminum oxide. Surface-coated hard alloy cutting tools that show longevity.