JPH01228703A - Surface coated cutting tip provided with al or al alloy cutting breaker - Google Patents

Abstract

PURPOSE:To aim at prolonging the life of a cutting tip by setting the content of Co in a tungsten carbide group ultrahard alloy base to a value between 0.5-3.5%, by forming a diamond coated layer on the surface of the base, and by setting the rake angle of the breaker to an angle between 20-35 deg.. CONSTITUTION:The content of Co in a tungsten carbide group ultrahard base in a cutting tool is set to a value between 0.5 and 3.5, and the rake angle of a breaker formed on the rake surface of a cutting blade of the tool is set to an angle between 20 deg. and 35 deg.. A diamond coated layer is formed on the outer surface of the cutting tool by a chemical evaporation process. With this arrangement, it is possible to remarkably restrain Al or Al alloy chip from being fused to the rake surface of the cutting blade so as to prevent occurrence of microchipping, thereby it is possible to enhance the life of the cutting tool.

Description

[Detailed Description of the Invention] [Industrial Field of Application] When this invention is used for cutting Aj and M alloys,
The present invention relates to a surface-coated cutting tip with a breaker, which exhibits excellent adhesion resistance to these cutting chips and, as a result, exhibits excellent wear resistance over a long period of time.

[Conventional technology]

Conventionally, in general, for cutting A1 and match gold, 1 weight - (hereinafter - indicates weight) contains Co: 4 to 6%,
Furthermore, carbides and nitrides of Ti, Ta, and Nb (hereinafter, (Ti, Ta, Nb)C.
one or more of the following (indicated by N) = 0.5 to 3,
5%, the remainder is composed of tungsten carbide (hereinafter referred to as we) and unavoidable impurities, and the rake face of the cutting edge is 15° to 18°.
A cutting tip with a breaker formed at a rake angle is used.

[Problem to be solved by the invention]

However, with the conventional cutting tips mentioned above, cutting chips generated during cutting of Al and Al alloys are welded to the rake face of the cutting edge, and the welded edges are extremely strong, resulting in welding during cutting. When it is peeled off from the rake surface,
Remove part of the cutting edge.

Currently, it only has a relatively short service life due to micro-chipping.

[Means to solve the problem]

Therefore, the inventors of the present invention, etc., from the above-mentioned viewpoint.

In order to develop a cutting tip that exhibits excellent wear resistance without welding of cutting chips to the rake surface of the cutting edge when cutting Al and Al alloys, we conducted research with a particular focus on the conventional cutting tips mentioned above. As a result, the Co content of the WCC cemented carbide base material in conventional cutting inserts was reduced to 0.5 to 3.5'II, and the rake angle of the breaker formed on the rake face of the cutting edge was increased to 20° to 20°. 35°, and a diamond coating layer is formed on the surface of the cutting tip using a normal chemical vapor deposition method, the adhesion of the Al and Al alloy cutting layer to the rake surface of the cutting edge is significantly suppressed, and the micro- The occurrence of chipping is eliminated, and the above substrate is further coated with rs.

(Internal standard)
on Organization) standard C01~CO
By uniformly dispersing a small amount of free carbon in S, it becomes a trap that further improves the adhesion of the diamond coating layer formed on the surface, thereby extending the service life of the diamond coating layer. We have obtained the knowledge that

This invention was made based on the above findings.

Contains Co 2 0.5 to 3.5 To h, and further if necessary.

(a) Trace amounts of free carbon from CO1 to CO8 according to ISO standards.

fbJ (Ti, Ta, Nb) One or more of CN: 0.5 to 3.51 s.

A composition containing either or both of the above (al and (b)), with the remainder consisting of we and unavoidable impurities (if it contains the above free carbon, it has a structure in which the free carbon is finely and uniformly dispersed). A diamond coating layer is formed on the surface of the WCC cemented carbide base material, and the rake angle of the breaker formed on the rake face of the cutting edge is set to 20.
Breaker for cutting Al and Al alloys at ~35°
It is characterized by a surface-coated cutting tip.

Next, in the cutting tip of the present invention, the composition of the base and the reason why the rake angle of the breaker is limited as described above will be explained.

(a) Co content CO acid component forms a binder phase and has the effect of improving the toughness of the substrate, but if the content is less than 5% CL, the desired toughness cannot be secured and the cutting edge On the other hand, if the content exceeds 3.5%, the adhesion of the diamond coating layer will decrease, and the adhesion of the diamond coating layer will decrease. The content was set at 0.5-3.5%.

(b) Free carbon content Free carbon has the effect of preventing graphitization of diamond deposited on the surface of the substrate and further improving its adhesion to the substrate, so it may be included as necessary. ,
If the content ratio is less than 001 in terms of rso, the desired effect cannot be obtained.

On the other hand, if the content exceeds the same COS, the toughness of the substrate will decrease, so the content is defined as C'O1 to C08 according to the ISO standard.

(c) (Ti, Ta, Nb) C-N(Ti
, Ta, Nb) For C-N, increase the hardness of the base.

It is included as necessary because it has the effect of improving wear resistance, but if the content is less than 0.5%, the desired effect cannot be obtained; on the other hand, if the content is less than 3.5%, If it exceeds the content, the toughness decreases and chipping is likely to occur on the cutting edge, so the content was set at 0.5 to 3.5%.

(dl Rake angle of the breaker If the rake angle is less than 20°, the flow of cutting chips will not go smoothly, a melt layer will easily occur, and the diamond coating layer will peel off. On the other hand, the rake angle is 35°
The rake angle of the breaker was set at 20° to 35° because if the angle exceeds 20°, the cutting edge is likely to be damaged.

〔Example〕

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

As raw material powders, WC powder and TaC powder both have an average particle size within the range of O18 to 3.2 μm.

Prepare NbC powder, TiN powder, TaN powder, N1)N powder, (W, Ti)・C powder, and COC powder,
Furthermore, finer carbon black is prepared, and these raw material powders are blended into a predetermined composition, mixed, and then press-molded into a green compact. Sintered in a vacuum at a temperature of 1460°C for 2 hours, and those containing less than 2 drops of Co were sintered in a vacuum at a temperature of 1460°C for 1 hour, and then HIP treatment was performed at 1400°C, and the first
A base material having the composition shown in the table is used, a breaker with a rake angle also shown in Table 1 is formed on this base material by polishing, and then these base materials are
.

Using the thermionic emitter method, a metallic tungsten filament placed 3 cIt away from the substrate surface was heated to 2000°C, and C) f4 and H2 (D mixed reaction gas (cH4/H2
: 1/99 in volume ratio) was introduced at a rate of 300 dlm while maintaining the pressure in the furnace at 20 torr, and the vapor phase precipitation reaction was carried out for a predetermined period of time to produce diamond with the average layer thickness shown in Table 1. By forming a layer, surface-coated cutting chips with a breaker of the present invention (hereinafter referred to as the present invention coated chip) 1 to 20 and comparative surface-coated cutting chips with a breaker (hereinafter referred to as the comparative coated chip) 1-4 were manufactured, respectively. .

In addition, comparative coated chips 1 to 4 were all tested under one of the conditions of component composition and rake angle of the breaker (first
Conditions marked with "Eastern" in the table) are outside the scope of this invention.

For comparison purposes, the chemical composition of the cutting tip and the rake angle of the breaker were as shown in Table 1, and a conventional cutting tip with a breaker (hereinafter referred to as A conventional chip (referred to as conventional chip) l-4 was manufactured.

Next, let's talk about these various chips.

Work material: AM-11% 8i alloy.

Cutting speed: 500 */m, feed 1): O, 1si
a*/rev,.

Depth of cut = 2B.

A continuous dry cutting test was conducted on M alloy under the following conditions, and the cutting time until the end of its service life was measured.

The state of the cutting edge after the test was observed and is shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, 1 coated chips of the present invention 1 to 20
In contrast, conventional chips 1 to 4 have excellent adhesion resistance against M alloy cutting chips and a significantly long cutting life due to the excellent wear resistance of the diamond coating layer. Well then.

The welding of the M alloy cutting layer to the cutting edge breaker surface is significant, which causes microchipping and shows only a short cutting life. It is clear that if the rake angle of the breaker is outside the scope of the present invention, the desired cutting life will not be exhibited.

As mentioned above, the surface-coated cutting tip with a breaker of the present invention exhibits excellent cutting performance over a long period of time, especially when used for cutting Al and Al alloys.

Claims (4)

[Claims] (1) A diamond coating layer is formed on the surface of a tungsten carbide-based cemented carbide substrate containing 0.5 to 3.5% by weight of Co, with the remainder consisting of tungsten carbide and unavoidable impurities, and A surface-coated cutting tip with a breaker for cutting Al and Al alloys, characterized in that the rake angle of the breaker formed on the rake face of the cutting blade is 20° to 35°. (2) Co: 0.5 to 3.5% by weight, and contains a trace amount of free carbon of C01 to C08 according to ISO standards, with the remainder consisting of tungsten carbide and unavoidable impurities, and the free carbon is fine and uniform. A diamond coating layer is formed on the surface of a tungsten carbide-based cemented carbide base body having a dispersed structure, and the rake angle of the breaker formed on the rake face of the cutting blade is 20° to 35°. Surface-coated cutting tip with breaker for cutting Al and Al alloys. (3) Contains Co: 0.5 to 3.5% by weight, and further contains T
one of carbides and nitrides of i, Ta, and Nb
Forming a diamond coating layer on the surface of a tungsten carbide-based cemented carbide substrate containing 0.5 to 3.5% by weight of one or more species, with the remainder consisting of tungsten carbide and unavoidable impurities; A surface-coated cutting tip with a breaker for cutting Al and Al alloys, characterized in that the breaker formed on the rake face of the cutting edge has a rake angle of 20° to 35°. (4) Co: 0.6 to 3.5% by weight, and contains a trace amount of free carbon of C01 to C08 according to ISO standards, and further contains one of carbides and nitrides of Ti, Ta, and Nb or Two or more types: Contains 0.5 to 3.5% by weight,
The remainder consists of tungsten carbide and unavoidable impurities,
In addition, a diamond coating layer is formed on the surface of the tungsten carbide-based cemented carbide having a structure in which free carbon is finely and uniformly dispersed, and the rake angle of the breaker formed on the rake face of the cutting blade is set to 20° to 35°. A surface-coated cutting tip with a breaker for cutting Al and Al alloys.