CENTERING METHOD OF GROOVE PART IN BUTT WELDING OF TUBE

摘要

PURPOSE:To perform centering of groove parts with a high precision, by providing fixed pieces and a centering piece in groove part of tube ends and by adjusting the gap between tube ends by wedge-form driving pieces and by correcting mismatching between tube wall parts of tube ends by pulling or pressing fixed pieces in the longitudinal section passing through their centers and including diameters of tubes. CONSTITUTION:Plural fixed pieces fixed onto the outside circumferential wall face of tube 1, fixed pieces on the outside circumferential wall face of tube 2 which correspond to fixed pieces 3, and centering piece 5 are provided. Next, wedge-form driving pieces are driven in gaps 53, 54, 55 and 56 formed by fixed pieces 3 and 4 and centering piece 5 to adjust the gap at the tube end between tubes 1 and 2 in the longitudinal direction. Further, the driven piece is driven at the aperture edge formed by adjusting holes 31 and 41 of fixed pieces 3 and 4 and reinforcing base stands 57 and 58 of centering piece 5, and tubes 1 and 2 are pulled or pressed to correct mismatching between tube wall parts at tube ends. After completion of welding for the first layer in groove parts at tube ends, driven pieces and centering piece 5 are removed, and fixed pieces 3 and 4 are ground.