METHOD FOR PREVENTING BRITTLE FRACTURE OF WELD ZONE

摘要

PURPOSE:To prevent the brittle fracture of a weld zone by carrying out uniform local annealing along a circular weld line for a nozzle or a nozzle reinforcing plate to be welded to a pressure vessel so as to produce uniform compressive stress in the direction of the weld line on the outside of the weld line. CONSTITUTION:A nozzle 2 or a nozzle reinforcing plate 3 having a welded nozzle 2 is welded to the body 1 of a pressure vessel. At this time, a circular weld bead 4 for the nozzle 2 or a circular weld bead 5 for the plate 3 is heated to the annealing temp. of the material along the whole weld line with a ring burner before welding to produce a compressive stress field 8 around the weld bead 4, 5 in the peripheral direction.