TWO SIDED WELDING METHOD AND TWO SIDED WELDED STRUCTURE

PROBLEM TO BE SOLVED: To provide a two sided welding method, with a double U type bevel joint composed of tube members or plate members of thick plates requiring two sided welding as an object, which can obtain a two sided laminated weld zone having low deformation, high efficiency and high quality, and is further effective for the improvement of productivity and the reduction of cost, and to provide a two sided welded structure. SOLUTION: In the two sided welding method, the bottom part of a bevel 3 on the surface side formed at the central part of the plate thickness T of the double U type bevel joint or the vicinity thereof is subjected to initial layer uranami welding, till it reaches a lamination bead height Hb in the range from the bottom part of the bevel 3 including the initial layer welded part 15 to 1/5 to 2/5 of the bevel depth Ho1 before welding or the bisected plate thickness T, or it reaches a residual bevel depth Hk in the range of ≤4/5 to ≥3/5 of the bevel depth Ho1 before welding, or the prescribed upper limit value of the shrinkages of the bevel shoulder widths w1 and w2 approaches 2 mm, surface side lamination welding is performed, thereafter, back side lamination welding is performed from the bottom part B2 of the bevel of the U type bevel joint on the back side to the final layer at the upper part of the bevel, and subsequently, surface side lamination welding is performed from the remaining bevel part on the surface side to the final layer at the upper part of the bevel. COPYRIGHT: (C)2009,JPO&INPIT