| 摘要 |
PURPOSE:To prevent the SR crack to be generated at the position being affected by the double thermal cycles, by previously making a groove at a specified position covering a specified range, and by filling this groove with mild steel, etc., of a low sensibility against the SR crack, at build-up welding on the surface of a low alloy steel plate with the austenitic steel. CONSTITUTION:At build-up welding on the surface of the low alloy steel plate for use of the pressure vessel with the austenitic steel, a groove 1 of size larger than the size of the welding heat affected zone is previously made at the position to be affected by the double thermal cycles; the mild steel of low sensibility against the SR crack, that is, the steel 2 including the low carbon and low impurity elements like as P, S, As, Sn, Sb, etc., being similar to the parent metal, is filled by welding into above groove 1. Next, the overlap welding for the welding beads 3, 4, is worked. The heat-affected structure due to the specified double thermal cycles is formed within a range of the groove 1, and the material to be welded is free from the heat- affection, so that the generation of the SR crack can be prevented. |
