WELDING PROCESS FOR REPAIR OF THICK SECTIONS

摘要

A double-sided tribrid welding technique and apparatus for root pass welding of narrow groove welds. The welding technique utilizes three welding devices. A welding apparatus on a backside of the weld joint may strike an arc on the backside of the weld joint; a welding apparatus on a narrow groove side of the weld may strike an arc within the narrow groove weld joint, while the remaining welding apparatus is a laser that can help establish a keyhole as a common pool of molten metal at the root without burning through the root. Once the arcs are struck substantially simultaneously and the laser is energized, the welding heads move simultaneously, the arc welders assisting in maintaining pre-heat temperature, while minimizing distortion and cracking. Adjusting arc weld parameters provides deformation on completion of the root pass so as to compensate for distortion due to metal shrinkage in subsequent passes.