Sumitomo Electric Industries, Limited

Hokkaido Sumiden Precision Industries, Ltd.

Kazutaka Isobe

Toshio Nomura

Nobuyuki Kitagawa

Kazuo Noguchi

Keiichi Tsuda

Akihiko Ikegaya

Yoshikatsu Mori

Masaaki Tobioka

Yasuhiro Shimizu

Kunihiro Takahashi

Isao Yamazaki

A nitrogen-containing sintered alloy includes at least 75 and not more than 95 percent by weight of a hard phase containing Ti, a group 6A metal and WC in a prescribed composition, and at least 5 and not more than 25 percent by weight of a binder phase containing Ni, Co and unavoidable impurities. The alloy contains at least 5 and not more than 60 percent by weight of a carbide, nitride or carbonitride of Ti, and at least 30 and not more than 70 percent by weight of a carbide of a metal belonging to the group 6A of the periodic table. The atomic ratio of nitrogen/(carbon+nitrogen) in the hard phase is at least 0.2 and less than 0.5. The alloy includes a soft layer containing a binder phase metal and WC at its outermost surface, and includes a layer that hardly contains any of the hard phase containing WC in a region immediately under the soft layer, with a thickness of at least 3 .mu.m and not more than 30 .mu.m. A nitrogen-containing sintered alloy with such a composition can be employed as a cutting tool having a high reliability even without a surface coating and even for working under conditions causing strong thermal shock.

Nitrogen-containing sintered alloy containing a hard phase

A titanium carbonitride-based alloy which is excellent in chipping resistance and wear resistance is disclosed. A hard phase is a carbide (TiMC), a nitride (TiMN) or a carbonitride (TiMCN) of Ti and at least one metal (M), other than Ti, selected from those belonging to the groups IVa, Va and VIa of the periodic table. A binder phase contains Co and Ni as main components. When the structure of the titanium-based alloy is observed with a scanning electron microscope, particles forming the hard phase in the alloy have black core parts which are located on core portions to appear black and peripheral parts which are located around the black core parts to appear gray. Assuming that A and B represent particles having the black core parts occupying areas of at least 30% of the overall particles A and those having the black core parts occupying areas of not more than 30% of the overall particles B respectively, the area ratio of the particles A to the particles B satisfies a condition of 0.3.ltoreq.A/(A+B).ltoreq.0.8.

Titanium-based alloy

Nitrogen-containing sintered hard alloy

Throw-away tipped drill

Cermet alloy containing nitrogen

A drill bit has a throw-away drill bit tip in the form of an insert (21, 31) secured to a shank (22, 32) to be mounted in a drilling tool. The insert (21, 31) is disengageably mechanically connected to the shank (22, 32) without any screws. The insert (21, 31) is formed of a silicon carbide whisker reinforced alumina sintered body, and the shank (22, 32) is made of steel. Due to this structure, the insert (21, 31) has an excellent wear resistance and an adhesion resistance. The shank (22, 32) has a sufficient toughness against breakage. Such a drill bit does not require any resharpening for continuous use during bit life.

Throw-away tipped drill bit

A drill bit has a throw-away drill bit tip in the form of an insert (21, 31) secured to a shank (22, 32) to be mounted in a drilling tool. The insert (21, 31) is disengageably mechanically connected with the shank (22, 32) without any screws. At least a cutting edge of the insert (21, 31) is made of a diamond or cubic boron nitride sintered body, and the shank (22, 32) is made of steel. Due to this structure, the insert (21, 31) has an excellent wear resistance and an adhesion resistance. The shank (22, 32) has sufficient toughness against breakage. Such a drill bit does not require any resharpening for continuous use during bit life.

A drill is formed by a hard dispersed phase of WC and a B-1 type solid solution, and a bond metal phase of an iron family metal. The composition of the hard dispersed phase is expressed as (W.sub.a M.sub.b) (C.sub.x N.sub.y), where M represents Ti, or two or more metals, including Ti but excluding W, selected from the group IVa, Va and VIa of the periodic table, and a, b, x and y represents molar fractions which are defined by relational expressions of a+b=1, x+y=1, x&gt;0, y.gtoreq.0 and b.gtoreq.0.4. The bond metal phase occupies at least 13 volume percent and not more than 30 volume percent of the cemented carbide.

Cemented carbide drill

High hardness and high toughness nitrogen-containing sintered hard alloys or cermets useful for cutting tools, in particular, high speed cutting are provided which comprises a hard dispersed phase consisting essentially of a mixed carbonitride of titanium and at least one element selected from the group consisting of Group IVa, Va, and VIa elements of Periodic Table, except titanium, and a binder metal phase consisting essentially of at least one metal selected from the group consisting of nickel and cobalt, and unavoidable impurities, the hard dispersed phase having previously been subjected to a solid solution forming treatment at a temperature of at least the sintering temperature before sintering.

Growing community of inventors

Hyogo, Japan

Kazutaka Isobe