Fuji Oozx Inc.

Hiroaki Asanuma

Masahito Hirose

Akiyoshi Mori

Akihiro Hamada

Yuji Takano

Ryousuke Hada

A rod material made of Ti alloy has a larger diameter portion at the end, which is joined with the end of material made of Ti&mdash;Al intermetallic compound, by friction welding, to form a poppet valve for an internal combustion engine. Instead of providing such larger diameter portion, the end of the material made of Ti&mdash;Al intermetallic compound may be heated to facilitate joining.

Method of joining different metal materials by friction welding

A Ti alloy poppet valve consists of a valve stem and a valve head, and is employed as intake or exhaust valve in an internal combustion engine of an automobile. O is put into the valve in a furnace at very slight amount and heated to introduce oxygen atoms into titanium of the valve to form a Ti&mdash;O interstitial solid solution without making titanium oxides. The valve is strengthened to increase hardness and wear resistance.

Ti alloy poppet valve and a method of manufacturing the same

Ti alloy is embedded in a powder such as graphite and heated with the powder in an oxygen atmosphere. Oxygen atoms are diffused into the Ti alloy to form an oxygen diffusion layer of Ti&mdash;O solid solution, thereby increasing wear resistance of the valve. A poppet valve in an internal combustion engine may be made of such Ti alloy.

Ti alloy surface treatment

A bar material is made of an (&agr;&plus;&bgr;) or a near &agr; Ti alloy which comprises a regular &agr; structure, and the end thereof is heated at a temperature above its &bgr; transformation point by an electric forging device to form an enlarged portion. The enlarged portion is immediately formed by hot forging to make a valve head of a poppet valve which is employed in an internal combustion engine. The valve head comprises an acicular &agr; structure which provides higher fatigue and tensile strengths.

Method of manufacturing a Ti alloy poppet value

A method of manufacturing and Al alloy tappet, used in an internal combustion engine, includes supplying wear resistant particles on a surface of a light metal tappet body, the surface slideably contacting a cam, kneading said particles with a surface layer of the surface of the tappet body to imbed them and then changing the surface layer after kneading to a flat surface.

Method of manufacturing tappet in an internal combustion engine

An Al alloy poppet valve is used in an internal combustion engine and has a valve head and a valve stem. At least the valve head is made of non-heat-treatable Al alloy in which ceramic particles such as oxide and carbide are uniformly dispersed, thereby increasing wear resistance and durability.

Al alloy poppet valve

A poppet valve in an internal combustion engine of a vehicle consists of a valve body which comprises a valve stem and a valve head at one end of the valve stem. An oxidized layer is formed on portions of the valve body which contacts another valve-operating member. On the oxidized layer, a carburized layer is formed to cover the whole surface to increase wear resistance and fatigue strength of the valve.

Ti alloy poppet valve and surface treatment thereof

An Al alloy poppet valve is used in an internal combustion engine. The poppet valve comprises a valve stem and a valve head at the end of the valve stem. The valve head has a tapered valve face, which is engaged on a valve seat when an inlet port is closed by the poppet valve. The valve face has a thermal hardened layer on the surface and an inner alloy layer, thereby increasing mechanical strength to provide high durability and reliability.

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Fujisawa, Japan

Hiroaki Asanuma