Abstract: A laser processing apparatus according to the present invention includes a laser oscillator that emits a continuous-wave or pulsed-wave laser beam for heat processing or a pulsed-wave laser beam for surface treatment, an incident optical system that causes the laser beam emitted from the laser oscillator to enter an optical fiber, a condenser lens that condenses the laser beam emitted from the optical fiber, and a processing unit that moves close to a processing object by carrying the condenser lens and irradiates a surface of the processing object with a laser beam, in which the laser oscillator emits the laser beam for the heat processing when performing the heat processing and emits the laser beam for the surface treatment when performing a pre-treatment or a post-treatment for the heat processing.

Abstract: A repair method for a structure having an open flaw in a welding heat affected portion, including, removing at least a part of the open flaw and thereby forming a concave portion in the welding heat affected portion, forming build-up weld layers so as to fill the concave portion, treating a surface of the build-up layers to reduce tensile residual stress by means of at least one of laser peening, shot blasting and water jet machining. Also disclosed is an apparatus suitable for carrying out the repair method.

Abstract: A repair method for a structure having an open flaw in a welding heat affected portion, including, removing at least a part of the open flaw and thereby forming a concave portion in the welding heat affected portion, forming build-up weld layers so as to fill the concave portion, treating a surface of the build-up layers to reduce tensile residual stress by means of at least one of laser peening, shot blasting and water jet machining. Also disclosed is an apparatus suitable for carrying out the repair method.