| 摘要 |
PURPOSE:To uniformly perform the modification of a surface without impeding laser beam penetration by collecting laser beam to irradiate on the inside surface of a tube and traveling an irradiation position on the axial direction with blowing shielding gas on an irradiating part. CONSTITUTION:The optical system arranged at the deterioration part like a weld heat affected zone the working torch 16 consisting of the shield gas supply nozzle 18, the infrared sensor 19, which an information is transmitted to a detecting device by the optical fiber 14, and the heat resisting glass 17 are traveled on the axial direction. While the shield gas is blown on the irradiation part in order to protect the working atmosphere by removing metal vapor, plasma, etc., generated at this time, the laser beam 3 irradiates and the optical system is traveled under a constant speed to melt a surface only. Thus, the surface molten modification layer 5 excellent in uniform corrosion resistance or stress corrosion crack resistance or wear resistance over the prescribed zone of the tube inside surface is formed to prevent deterioration of structure. |
