WELDING METHOD AND DEVICE OF STEEL TUBE FOR PROTECTING OPTICAL FIBER TO BOND LONGITUDINAL GAP OF TUBE MANUFACTURED BY ROLLING STEEL SHEET

摘要

PURPOSE: A welding method of a steel tube for protecting optical fiber and a device thereof are provided to increase the effective area of the laser beam, and to improve welding efficiency and quality by irradiating the laser beam to the steel tube in inclining to the vertical reference line. CONSTITUTION: In a welding method for bonding a gap longitudinally formed in an optical fiber protection steel tube(100) manufactured by rolling the steel sheet, the end of a tungsten electrode(30) is opposed to the welding portion of the gap with a TIG welding unit. A laser welding unit(20) is arranged to irradiate the laser beam placed in the same plane with the reference line and the major axis of the gap on the welding portion, and the angle is formed between the reference line vertically arranged to the steel tube and the optical axis of the laser beam. The steel tube is transferred longitudinally, and the TIG welding unit and the laser welding unit are operated.