PURPOSE:To provide a titled jig which minimizes residual stress and sensitization and can improve SCC resistance, by constituting the same in such a way that the ejection holes for cooling water are beforehand adjusted to enable the cooling of the weld heat affected zones on both base pipe side and nozzle stub side in the weld zone of the nozzle stub. CONSTITUTION:A nozzle stub 2 is mounted in the weld zone 3 of a base pipe 1, and after the initial layer in the weld zone 3 is subjected to TIG welding, a jig for water cooling consisting of a forward end part 4A and an intermediate part 4B is mounted to the nozzle stub 2 to spray water and cool the nozzle stub. The cooling is accomplished by adjusting beforehand the holes in the part 4A and part 4B of the jig by a mockup so that both of the heat affected zone A on the base pipe side and the heat affected zone B on the nozzle stub side are thoroughly cooled. The welding in the weld zone 3 is completed under such cooling.
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