JPH1112025A - Cutting tool made of aluminum oxide-sintered material excellent in hardwearing property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of an Al2 O3 group-sintered material excellent in hardwearing properties. SOLUTION: This cutting tool consists of an Al2 O3 group-sintered material, the internal composition of which contains 20-40% of TiCN, 1-3% of Co, 3-1% of Ni and substantially Al2 O3 as the rest, and has a surface aluminum-formed layer substantially consisting of grown Al2 O3 in 0.5-10 μm average layer thickness in the surface portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention has excellent abrasion resistance, aluminum oxide exhibit excellent cutting performance for a long period of time (hereinafter, indicated by Al ₂ O ₃₎ based sintered material cutting tool made It is about.

[0002]

2. Description of the Related Art Conventionally, generally, for example, Japanese Patent Application Laid-Open No. 56-54
No. 271 (hereinafter referred to as "%").
Indicates weight%), 4a, 5a, and 6a of the periodic table
Group metal nitrides and carbonitrides (hereinafter collectively referred to as
At least one of the following:
5-60%, with the remaining 40-95% substantially
Al_Two O_Three Having a composition consisting of _Two O_Three Basic ceramic
Al composed of_Two O_Three Base ceramic cutting tool
This is known for continuous cutting and intermittent cutting of steel, cast iron, etc.
It is also known that it is widely used for cutting. Further
In addition, the conventional Al_Two O_Three Base ceramic cutting tool
However, as raw material powder, Al_Two O_Three And metal nitriding and carbonitriding
Compound powder and blend it into a prescribed formulation.
Yttrium oxide (hereinafter referred to as sintering accelerator)
Bottom, Y_Two O_Three2% or less
Mix in the following ratio and press-mold into a green compact
Then, the green compact is placed in an inert gas atmosphere at 1600 to 1
Sintered at a temperature of 900 ° C.
In an active gas atmosphere, pressure: 50 to 200 MPa, temperature:
HIP treatment at 1400-1700 ° C
It is also known to be manufactured from.

[0003]

On the other hand, in recent years, the use of FA in cutting devices has been remarkable, and there has been a strong demand for labor-saving cutting work. Accordingly, cutting tools have been required to have even higher wear resistance. However, the above-mentioned conventional Al ₂ O ₃ -based ceramic cutting tools do not always have sufficient wear resistance. In particular, wear rapidly progresses in high-speed cutting and heavy cutting such as high feed and high cutting. However, at present, the service life is reached in a relatively short time.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoints, as a result of conducting research to develop cutting tools that exhibit excellent wear resistance in heavy-duty cutting such as high-speed cutting and high feed and high cutting, as a raw material powder,
An Al ₂ O ₃ powder and a titanium carbonitride (hereinafter, referred to as TiCN) powder, which is one of the above-mentioned metal nitride / carbonitride powders, are identified. Further, using a Co powder and a Ni powder,
These are blended in a predetermined ratio, and a small amount of Y ₂ O ₃ powder is used as a sintering accelerator (0.05 to
0.5%), mixed in a blended state, and then pressed into a green compact, and the green compact was sintered under the normal conditions described above, and HI
When a cutting tool is manufactured by performing the P treatment, the Co powder and the Ni powder promote the grain growth of Al ₂ O ₃ on the surface during sintering and promote the movement of the grain boundary of the grown Al ₂ O _{3 to} the surface. Growth A
l ₂ O ₃ is concentrated on the surface portion (in this case, the internal Al ₂ O ₃ is suppressed in grain growth and grain boundary movement by TiCN, so that strength and toughness are maintained),
Therefore, the resulting cutting tool was replaced with TiC
N: 20 to 40%, Co: 1 to 3%, Ni:
0.3 to 1%, containing, having an interior composition balance being substantially Al ₂ O _3, and the surface section, substantially Growth A
The surface alumina formation layer consisting of l ₂ O ₃ alone is 0.5 to 1
When it is made of an Al ₂ O ₃ -based sintered material having an average layer thickness of 0 μm, the surface alumina generation layer consisting essentially of only grown Al ₂ O ₃ is extremely hard, so Research has shown that even in heavy cutting, in combination with the excellent toughness and high strength inside the cutting tool, excellent wear resistance is exhibited over a long period of time.

The present invention has been made on the basis of the above-mentioned research results, wherein TiCN: 20-40%, Co:
1 to 3%, Ni: 0.3 to 1%, with an internal composition consisting essentially of Al ₂ O ₃ , and on the surface, substantially from only grown Al ₂ O ₃ comprising a surface alumina-yielding layer is constituted by the average layer Al ₂ O ₃ group sintered material present in the thickness of 0.5 to 10 [mu] m, the wear resistance of good Al ₂ O ₃ group sintered material cutting tool made It has features.

[0006] Next, A constituting the cutting tool of the present invention.
The average layer thickness of the inner composition and the surface alumina generating layer of l ₂ O ₃ group sintered material explaining the reasons for limiting as described above. (A) TiCN TiCN contains Al that is adjacent to each other inside the cutting tool.
_In addition to suppressing the grain growth and grain boundary movement of ₂ O ₃ , it also has the effect of improving the strength and toughness of the cutting tool and further improving the thermal shock resistance. However, if the content is less than 20%,
The desired effect cannot be obtained in the above-mentioned action, while the content is 4
If it exceeds 0%, the sinterability decreases, and the strength and toughness rapidly decrease.
0%, preferably 25 to 35%.

(B) Co In Co, Al ₂ O _{3 on the} surface of the cutting tool during sintering
It is an indispensable component for the formation of the surface alumina formation layer because it has an effect of promoting the grain growth of
If the content is less than 3%, the desired grain growth promoting effect cannot be obtained. On the other hand, if the content exceeds 3%, the heat-resistant plastic deformation property decreases, and uneven wear tends to occur during cutting.
３3%, desirably 1.5 to 2.5%.

(C) Ni Ni has an effect of promoting the movement of the grain boundary to the surface of the grown Al ₂ O ₃ in the coexistence with Co, thereby contributing to the formation of the surface alumina generation layer. If the amount is less than 0.3%, the desired effect cannot be obtained in the above-mentioned action, while if the content exceeds 1%, the heat-resistant plastic deformation property decreases as in the case of Co. 0.3-1
%, Preferably 0.5 to 0.8%.

(D) Average Layer Thickness of Surface Alumina Generating Layer The surface alumina generating layer is substantially made of Al ₂
Since it is composed only of O ₃ , it is extremely hard, so that the formation thereof significantly improves the wear resistance of the cutting tool. However, if the average layer thickness is less than 0.5 μm, the desired wear resistance improving effect is not obtained. On the other hand, if the average layer thickness exceeds 10 μm, chipping or chipping (small chipping) or the like tends to occur on the cutting edge, so the average layer thickness is 0.5 to 10 μm, preferably 1 to 5 μm. It was decided.

In manufacturing the cutting tool of the present invention,
Shows that Y as a sintering accelerator _Two O_Three Powder all over
Occupied ratio is 0.05-0.5%, preferably 0.1-
It is compounded at a rate of 0.3%,
If less than 0.05%, desired sinterability can be secured.
On the other hand, if the compounding ratio exceeds 0.5%,
Based on the reason that the strength suddenly decreases
It is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a cutting tool made of an Al ₂ O ₃ -based sintered material according to the present invention will be specifically described with reference to examples.
As raw material powders, Al ₂ O ₃ powder, TiCN powder, each having a predetermined average particle size in the range of 0.1 to 1 μm,
A Co powder and a Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 1, and Y is used as a sintering accelerator
₂ O ₃ powder was also blended at the ratio shown in Table 1, mixed for 48 hours in a ball mill, and then pressed into a green compact of a predetermined shape at a pressure of 1 ton / cm ^2. In an argon atmosphere of 0.11 MPa, temperature: 175
Sintering was carried out at 0 ° C. for 2 hours, followed by pressure: 1
JIS SNMN4 by performing HIP processing of heating to a temperature of 1600 ° C. in an argon atmosphere of 00 MPa.
The cutting tool 1 of the present invention having a throw-away tip shape of 32 and having an internal composition substantially the same as the above composition
And Comparative Cutting Tools 1 to 5 were manufactured, respectively.

The resulting cutting tools 1 to 5 of the present invention and comparative cutting tools 1 to 5 were observed using a scanning electron microscope with an arbitrary longitudinal section polished, and the rake face and relief of the cutting blade were obtained. The presence or absence of a surface alumina generation layer on each of the three surface portions of the surface was confirmed, and it was confirmed that the surface alumina generation layer was substantially composed only of grown Al ₂ O ₃ , and the thickness was measured. The measurement results are shown in Table 1 as average values.

The cutting tools 1 to 5 of the present invention and the comparative cutting tools 1 to 5 are as follows: Work material: JIS FC300, a round bar with two longitudinally spaced vertical grooves, cutting speed: 450 m / min, A wet high-speed intermittent cutting test of cast iron was performed under the following conditions: feed: 0.2 mm / rev, cutting depth: 1 mm, cutting time: 10 minutes, and the flank wear width of the cutting edge was measured. The measurement results are also shown in Table 1.

[0014]

[Table 1]

[0015]

From the results shown in Table 1, all of the cutting tools 1 to 5 of the present invention have substantially grown Al _{2 on the} surface thereof.
Since there is a surface alumina generation layer consisting only of O ₃ , and this surface alumina generation layer is extremely hard, it has much better wear resistance than the comparative cutting tools 1 to 5 in which the surface alumina generation layer is not formed. It is evident that it exhibits the property. As described above, the cutting tool made of an Al ₂ O ₃ based sintered material of the present invention can be used not only for continuous cutting and interrupted cutting under ordinary conditions such as cast iron and steel, but also for high-speed cutting and heavy cutting. However, since it exhibits excellent wear resistance over a long period of time, it can sufficiently respond to the use of FA in a cutting device and labor saving in cutting.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasushi Ogata 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Pref. Mitsubishi Materials Corporation Tsukuba Works

Claims (1)

[Claims] 1. Titanium carbonitride: 20 to 40% by weight
%, Co: 1 to 3%, Ni: 0.3 to 1%, with an internal composition consisting essentially of aluminum oxide, and on the surface, substantially from only grown aluminum oxide A cutting tool made of an aluminum oxide-based sintered material having excellent wear resistance, characterized in that the surface alumina-forming layer comprises an aluminum oxide-based sintered material having an average layer thickness of 0.5 to 10 μm.