| 摘要 |
PURPOSE:To decrease a high tensile residual stress of the inner surface, which is generated at the time of clad buildup welding, by applying a temperature operation for holding relatively the inner surface at a low temperature after the clad buildup welding, and also holding relatively the outer surface in a high temperature state. CONSTITUTION:An inner surface part 4 and an outer surface part 5 become a low temperature and a high temperature, respectively, by executing a buildup welding to the inner surface of a vessel, and thereafter, cooling the inner surface. The inner surface part 4 contracts due to a low temperature, and a deformation difference of delta is generated between said part and the outer surface part 5. The inner surface part 4 and the outer surface part are a continuous body, therefore, the inner surface part 4 is drawn by the outer surface part 5 having a high rigidity and a tensile stress is generated. After the inner surface temperature has reached some temperature, in a process for returning it to a room temperature, this time its method becomes reverse to the time of cooling, a deformation difference of delta is generated between the inner surface part 4 and the outer surface part 5 before returning to a room temperature, but since both of them are a continuous body, the inner surface side 4 receives the compression. In this regard, a clad steel 2 of the inner surface and a base metal 3 of the outer surface consist of each different material, and the clad steel 2 has a larger coefficient of linear expansion, therefore, the contraction and expansion quantity is larger than that of the base metal part, and the clad part is influenced greatly. |
