Application of YAG laser welding to gas turbine components

An investigation to apply YAG laser welding to gas turbine components was carried out. The materials of gas turbine such as Ni base alloy are difficult to weld by conventional arc welding methods because of large heat affection. But laser welding can reduce heat input compared with conventional methods and keeps the good repeatability. The welding parameter survey was carried out to satisfy the designing requirements. The YAG laser welding under appropriate conditions enables to prevent welding defects such as HAZ cracks and improves the weld joints quality and performance. Tensile test and low cycle fatigue test were carried out. Tensile strength and fatigue life of laser weld joints are same or higher than that of conventional manual TIG weld joints. The Automatic YAG laser welding system was also developed and put into practical use.