| 摘要 |
<p>PURPOSE: A structural steel having high strength ash with a superior in Sr property and a manufacturing method thereof are provided to maintain the strength after a SR processing step. CONSTITUTION: A structural steel comprises less than C 0.02~0.12 weight%, si 0.01~0.6 weight%, mn 0.3~2.5 weight%, less than P 0.02 weight% less than S 0.01 weight% al 0.005~ 0.5 weight%, nb 0.005~0.1 weight%, B 5~40 ppm, ti 0.005~0.1 weight%, N 15~150 ppm, and the rest Fe and the other inevitable impurities. The structural steel includes a bainitic ferrite and a granular bainite mixing tissue to the matrix tissue. The structural steel includes the MA organization on the second.</p> |
