A High Efficiency Method of Repairing Metal Structure using Local Laser Heating
上野 聡一 Souichi UENO 椎原 克典 Katsunori SHIIHARA 福田 健 Takeshi FUKUDA
Hot-wire systemLaser weldingTop-hat type laser
Importance of repairing structures in nuclear power plants as ountermeasures for Stress Corrosion Cracking is increasing be use many plants are aging. We have developed the underwater laser beam welding (ULBW) for the repair technique. In order to achieve faster and widespread repairing, we focused on a top-ht type laser beam and hot-wire system. The top-hat type laser eam has oblong energy distribution and contributes to expand heating area. The hot-wire system heats the welding wire befor e insertion and improves extent of melted welding wire. First we conducted heat conduction analysis and validated efficiency of the top-hat type laser beam. Next we conducted welding tests and optimized parameters concerned with welding condition; la ser scanning velocity, wire feeding velocity, and heating current. Consequently we demonstrated the possibility of high spee welding as twice as our traditional underwater laser welding by combination of top-hat type laser beam and hot-wire system.