| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel sheet with little welding distortion in which, as shape is secured in a thin material, medium temperature is high. SOLUTION: The steel sheet with little welding distortion has a composition comprising, by mass, 0.002 to 0.030% C, 0.05 to 0.5% Si, 0.2 to 2.0% Mn, 0.005 to 0.10% Al, 0.0010 to 0.0080% N and 0.060 to 0.30% Nb, and satisfying P≤0.025% and S≤0.010%, and the balance Fe with inevitable impurities, and in which the content of solid solution Nb is≥0.040%, and has a microstructure comprising bainite with a mean grain size of≤15μm by≥70% in area%. The microstructure further comprises ferrite with a mean grain size of≤15μm. The steel sheet has a sheet thickness of≤10 mm, and is used for welded structures. COPYRIGHT: (C)2006,JPO&NCIPI
|
