Patent ID: 8872446
Filing Date: 2014-10-28
Classification: B23K,H05H

Abstract:
1. A welding method for welding a cylindrical stiffening member to an outer circumference of a superconducting accelerator tube body using a laser beam in a process of manufacturing a superconducting accelerator tube, the welding method comprising: butting the cylindrical stiffening member and the superconducting accelerator tube body to form a butting portion as an irradiated face; irradiating a defocusing beam, as the laser beam, to the butting portion; and welding the butting portion between the cylindrical stiffening member and the superconducting accelerator tube body by melting the butting portion with the defocusing beam, wherein the laser beam is configured such that a distribution profile of energy density on the irradiated face to which the laser beam is irradiated is a Gaussian distribution profile having a peak section and an outer edge section, and the energy density of the peak section is 5.8×10 the energy density of an outer circumference of a region in which 50% of the total energy in the distribution profile of the energy density is included centered on the peak section is less than or equal to 75% of the energy density of the peak section, and the defocusing beam includes: a first region which evaporates and melts metal of the butting portion, the first region being configured of the peak section; and a second region which melts the metal of the butting portion without evaporation, the second region being configured of the outer edge section.