UNDERWATER REPAIR WELDING METHOD

摘要

A protection plate is welded to a metal structure in water so that the protection plate covers the surface of the structure including a portion to be repaired. The welding is carried out such that the periphery of the protection plate is welded in water by laser welding while inactive gas is supplied to portion to be welded to seal the portion to be repaired by the protection plate. Welding is carried out while the inactive gas is supplied to the portion to be welded coaxially with a laser beam during the laser welding. The plate is provided therein with an opening in advance so as to release vapor produced from water remaining during welding between the protection plate and the structure and the opening is sealed after the periphery of the protection plate is welded to the structure.