NARROW BEVEL WELDING METHOD, WELDED STRUCTURE, AND WELDING APPARATUS THEREFOR

PROBLEM TO BE SOLVED: To prevent stress-corrosion cracking or the like by changing residual stress generated by one side welding of a bevel joint into a compressing stress. SOLUTION: A narrow bevel welding in which one side surface welding is performed from the bottom part to the top part of the bevel joints 1, 2 formed by butting pipe members or plate members, includes: a primary layer back-side welding process 53 for forming a back-side bead 15 on the back surface side of the bevel bottom part; a first build-up welding process 41 for performing build-up welding up to a specific build-up bead height Hb in a first heat input quantity range Q1 after the primary layer back-side welding process 53; a second build-up welding process 42 for performing build-up welding from the remained bevel portion to a finish layer 39 (P=N) at the bevel upper part in a second heat input quantity range Q2 after the first build-up welding process 41. The first heat input quantity range Q1 used for the first build-up welding process 41 is 4-12 kJ/cm, and the second heat input quantity range Q2 used for the second build-up welding process 42 is 1-6 kJ/cm. COPYRIGHT: (C)2007,JPO&INPIT