Mitsubishi Heavy Industries Limited

Kei Osawa

Taiji Torigoe

Koji Takahashi

Kazuharu Hirokawa

Masahiko Mega

Yukihiro Hashimoto

Ryuichi Yamamoto

Masahiko Onda

Keisuke Ihara

Norikazu Tezuka

Nobuyuki Izutsu

A turbine rotor blade repair method which reduces the occurrence of cracks due to welding is provided. A turbine rotor blade repair method for repairing damage of a fin at a tip of a turbine rotor blade includes overlaying a damaged portion of the fin with metal by welding (step S); peening on a boundary region between the fin and the overlaying metal (step S); and after the peening, performing solution treatment to repair the damage of the fin of the turbine rotor blade (step S).

Turbine rotor blade repair method

A bolt has a male screw with a surface hardening portion that has an increased surface hardness and that is applied with a compressive residual stress. The male screw is formed by cutting the bolt, and performing a process to provide at least on the surface of the male screw of the bolt the surface hardening portion that has increased hardness and that is applied with a compressive residual stress. As a result, the fatigue resistance of the male screw is improved and the bolt is effective for use in a portion where the male screw is subject to a repetitive stress.

Bolt and manufacturing method of bolt

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Takasago, Japan

Kei Osawa