| 摘要 |
PROBLEM TO BE SOLVED: To provide a high toughness thick welded steel tube which has a base metal thickness of 25 mm or larger and is manufactured by one layer welding in the inner/outer surface, the high toughness thick welded steel tube which is excellent in sour-resistant characteristic and combines high toughness in seam weld metal with low hardness in a T-cross part. SOLUTION: The high toughness thick welded steel tube has the optimized compositions of the base metal and the welding metal. The composition of the steel tube particularly of the weld metal, is restricted to≤0.12% Mo, 0.010-0.03% Ti, 0.0005-0.0015% B,≤0.008% N, and≤0.035 O. Further, the Pssc defined by the expression, Pssc=C+Si/15+(Mn+Cu+Cr)/10+Ni/30+Mo/2+V/5+20×B-12×N-4×O, is restricted to 0.140-0.160%. COPYRIGHT: (C)2005,JPO&NCIPI
|
