Ceramic cutting tool

Details Ceramic cutting tool Ceramic cutting tool

1998-12-28

2001-06-19

Group, Karl (Department: 1755)

Compositions: ceramic

Ceramic compositions

Carbide or oxycarbide containing

C501S096100, C501S127000

Reexamination Certificate

active

06248681

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a ceramic cutting tool. More particularly, the present invention relates to a ceramic cutting tool suitable for cutting of, e.g., ductile cast iron (nodular graphite cast iron).
BACKGROUND OF THE INVENTION
In recent years, the rise in the speed and efficiency of machining has been in rapid progress. High performance ceramic materials which can cope with this tendency have been desired. For example, titanium carbide exhibits a high melting point and hardness and a low thermal expansion coefficient and shows no drop of thermal conductivity at high temperatures. Thus, titanium carbide is known as a high-temperature material having a high spalling resistance. However, titanium carbide can hardly be sintered. Thus, it has been considered indispensable that titanium carbide is complexed with a metal such as Co and Ni to form a cermet, making it possible to obtain a dense sintered product which can be used for cutting tool, etc. However, cermet has some disadvantages. Since the metals thus incorporated deteriorate the heat resistance of cermet, it can hardly be said that the excellent heat resistance of titanium carbide can be effectively exerted. For example, when used in high speed cutting of an iron-based material of high toughness and ductility, such as ductile cast iron, a cutting tool made of cermet soon comes to an end of its life due to its poor heat resistance.
In order to eliminate these difficulties, a titanium carbide-based ceramic material which comprises a solid solution of a metal in titanium carbide to resist adverse effects at high temperatures and exhibit improved heat resistance has been proposed (JP-B-2-25866 (The term “JP-B” as used herein means an “examined Japanese patent publication”), JP-A-62-36065 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”)). Although the ceramic material disclosed in the above publications has a good heat resistance, it disadvantageously exhibits a far lower toughness than the foregoing cermet and is liable to chipping.
On the other hand, as a titanium carbide-based ceramic material which exhibits improved toughness while maintaining its good high-temperature properties there has been proposed one comprising silicon carbide whisker incorporated therein (JP-B-8-16028). Although this titanium carbide-based ceramic material exhibits improved toughness due to the incorporation of silicon carbide whisker, it is disadvantageously liable to reaction of silicon in the whisker with iron in the material to be cut, resulting in remarkable deterioration of abrasion resistance when used in cutting of an iron-based material, particularly ductile cast iron.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a ceramic cutting tool mainly comprising a titanium-based hard phase having an excellent heat resistance and abrasion resistance which exhibits an excellent toughness and is capable of cutting a tough iron-based material such as ductile cast iron.
The ceramic cutting tool defined in a first aspect of the present invention comprises in its essential part a ceramic material mainly comprising a titanium carbonitride-based hard phase mainly comprising titanium carbonitride and an alumina-based phase mainly comprising alumina, said titanium carbonitride-based hard phase and alumina-based phase satisfying the following relationships:
10 wt %≦weight of Al
2
O
3
≦45 wt %;
51 wt %≦weight of TiCN≦89.5 wt %; and
96 wt %≦weight of Al
2
O
3
+weight of TiCN ≦99.5 wt %
wherein weight of Al
2
O
3
indicates the weight content of aluminum as calculated in terms of Al
2
O
3
; and weight of TiCN indicates the weight content of said titanium carbonitride hard phase, with the proviso that WTiCN is defined by WTi+WC+WN in which WTi, WC and WN are the weight content of titanium component, carbon component and nitrogen component, respectively.


REFERENCES:
patent: 3886254 (1975-05-01), Tanaka et al.
patent: 4632910 (1986-12-01), Lee et al.
patent: 4839315 (1989-06-01), Suzuki et al.
patent: 5017524 (1991-05-01), Moskowitz et al.
patent: 5196385 (1993-03-01), Suzuki et al.
patent: 5387561 (1995-02-01), Watanabe et al.
patent: 5439854 (1995-08-01), Suzuki et al.
patent: 5462901 (1995-10-01), Egami et al.
patent: 5955390 (1999-09-01), Mehrotra et al.
patent: 0 174 463 (1986-03-01), None
patent: 0 174 463 (1988-10-01), None
patent: 0592871A1 (1994-04-01), None
patent: 1 600 142 (1970-07-01), None
patent: 61-17473 (1986-01-01), None
patent: 61-26564 (1986-02-01), None
patent: 61-31358 (1986-02-01), None
patent: 61-10416 (1986-03-01), None
patent: 62-36065 (1987-02-01), None
patent: 63-225579 (1988-09-01), None
patent: 2-25866 (1990-06-01), None
patent: 6-122563 (1994-05-01), None
patent: 8-16028 (1996-02-01), None

Affiliated with

Also associated with

Rating

Ceramic cutting tool does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ceramic cutting tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ceramic cutting tool will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2448492