To provide a device for improving residual stress in an installed pipe, which can stably, reliably and uniformly heat a wide range of a pipe even with a thick wall.
This device for improving residual stress comprises: a laser oscillator 11 for projecting a laser beam 1; a first optical fiber 12 for guiding the laser beam 1 projected from the laser oscillator 11; an irradiation head 20 for irradiating the installed pipe 100 with the laser beam 1, which has a first reflecting mirror 24 for reflecting most of the laser beam 1 guided by the first optical fiber 12 therein; further a CCD camera 26 for detecting one part of the laser beam 1 having transmitted through the first reflecting mirror 24, which is arranged at the back side of the first reflecting mirror 24 in the irradiation head 20; and a control unit 15 for controlling the laser oscillator 11 so as to match the beam profile and beam intensity of the laser beam 1 projected from the laser oscillator 11 with a target value, on the basis of information obtained from the first CCD camera 26.
AKAHA TAKASHI
SUGIMOTO KENSHO
OTA TAKAHIRO
Tadahiro Mitsuishi
Yasuyuki Tanaka
Hiroshi Matsumoto
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