| 摘要 |
<p>PURPOSE:To improve residual stress by heating the zones on both sides of the longitudinal seam in the weld zone of a vessel and apart by the prescribed sizes from this seam, respectively, to establish residual stress beyond the yield point and then improving residual stress with respect to the horizontal seam so as to introduce the stress in the external surface of a large-sized vessel in the direction of compression. CONSTITUTION:In a vessel 1 having a weld seam 2 in a longitudinal direction, the regions apart from the center of the longitudinal seam 2 by the prescribed sizes L toward both sides, respectively, is made heating-inhibited zones 4. Heating zones 5 are set up outside the above zones, respectively, and heating is applied to these zones 5, by which stress exceeding the yield point is established in the vicinity of the longitudinal seam. Subsequently, residual stress is improved with respect to the horizontal seams 3 including the ends of the above longitudinal seam 2 in the weld zone of the vessel.</p> |
