| 摘要 |
PURPOSE:To enhance reliability and improve workability, by a method wherein only the periphery of a tube hole is build-up welded with a metal, and after inserting a pipe, seal welding is conducted. CONSTITUTION:Prior to seal welding for a pipe 2 and tube plates 12, 13, only the peripheries of the tube holes are build-up welded with a metal 10-12, and after inserting the pipe 2 through the holes, seal welding is conducted. Accordingly, since a conventional local heat treatment by a burner inserted through a plug hole or the like is unnecessitated and it is sufficient to conduct only an overall heat treatment in a furnace or the like, stress and corrosion cracking is prevented, and reliability is enhanced. In addition, since seal welding which requires fine operating conditions can be conducted without any preheating, workability is improved. |
