Nippon Kokan Kabushiki Kaisha

Hiromi Okamoto

Takemi Yamada

Masaaki Mizushina

Koji Toyota

Tamataro Satoh

A method of producing an exhaust valve for a diesel engine comprising the steps of cutting a part of a valve or valve seat body, depositing or spraying onto the cut part a mixture of grains of ceramics and metals, and varying the proportion of grains of ceramics and metals during the deposition or spraying so that the deposited or sprayed layer will vary in content of metal and ceramics with the proportion of ceramics increasing with the increase in height from the valve or seat body of the coated layer, and then subjecting the coating to pressure of 3 to 7 Kg/mm.sup.2 and concurrently heating the coating to 700.degree. to 800.degree. C., thereby to produce a contact surface which forms the contact point between the valve and valve seat which has better adhesion, is close to the body, and has better corrosion resistance, anti-invasion properties, and good thermal shock resistance.

Method of producing an exhaust valve for diesel engine

This invention is concerned with an exhaust valve for Diesel engine and a method thereof, in which a seat of the exhaust valve is formed with coated layer comprising ceramics and metals, the layer becoming thicker in density of ceramics as coming nearly to the surface thereof. The seat may be formed with the coated layer by subjecting to pressing-heating treatment after coating. This kind of the exhaust valve is provided by coating ceramics and metals onto a seating portion of the mother material such that ceramics becomes thicker in density as advancing to the surface, and heating the coated layer in electric conductivity while pressing the layer with the tool in non oxidizing atmosphere.

Exhaust valve for diesel engine and production thereof

This invention is concerned with an exhaust valve for Diesel engine and a method thereof, in which a seat of the exhaust valve is formed with coated layer comprising ceramics and metals, the layer becoming thicker in density of ceramics as coming nearly to the surface thereof. The seat may be formed with the coated layer by subjecting to pressing-heating treatment after coating. This kind of the exhaust valve is provided by coating ceramics and metals onto a seating portion of the mother material such that ceramics become thicker in density as advancing to the surface, and heating the coated layer in electric conductivity while pressing the layer with the tool in non oxidizing atmosphere.

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Yokohama, Japan

Hiromi Okamoto