Original welding processes using the combination of a hot‐wire system and laser heat source are developed in Hiroshima University. These processes have advantages of low heat input, low dilution, high controllability of weld metal and HAZ properties, highefficiency, and so on. Some applications of hot‐wire laser welding process for a narrowgap joint, fillet welded joint, heavy‐thick vertical joint will be introduced. The observation techniques using image sensors for temperature cycle, solidification phenomena during welding will also be introduced.
