Mitsubishi Heavy Industries Limited

Masaya Kanikawa

Koji Takahashi

Masahiko Mega

Yoshitaka Uemura

Kengo Yamaguchi

Minoru Ohara

Ken Fujita

Toshihiko Tsunatani

Mao Takei

Toshinari Nishimura

Syuho Tsubota

Takahiko Hirohata

The invention improves reliability of a valve gear in which a cobalt-based alloy is welded by plasma power building up. The valve gear includes a bearinghaving a sliding surface against a valve shaft. The valve gear having a welded layermade of heat-resistant cobalt-based alloy, based on plasma powder building up, formed on the sliding surface against the valve shaft. The welded layerincludes a first welded layerformed on the surface of the bearing, having a dilution ratio of 5 to 25% and a second welded layerformed on the first welded layer, having a dilution ratio of 50% or less of the dilution ratio of the first welded layer. The dilution ratio indicates the penetration amount of the welding metal into the base metal, and is a value obtained by B/A&#xd7;100 (%) wherein A represents the total amount of the welded metal and B represents the amount of the welding metal penetrating into the base metal.

Valve gear with a bearing having a sliding surface against a valve shaft

A tip plug is capped on a boss section so as to fit to a hole which is used for detaching a core which is formed in a blade tip section of the gas turbine blade. A butt-section T is melted so as to form a butt-welding section by using a YAG laser beam. Also, parameters such as an interval between the butt-section T, a member for forming the tip plug, condition for a laser welding operation, and a defocus position of the laser beam are optimized.

Method of closing a hole in a gas turbine blade top by laser welding

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Hyogo, Japan

Masaya Kanikawa