| 摘要 |
<p>PURPOSE: A manufacturing method for a high-strength structural steel material having a tensile strength of 750MPa and a structural steel material manufactured thereby are provided to minimize the load of a rolling mill using an air-cooled material. CONSTITUTION: A manufacturing method for a high-strength structural steel material having a tensile strength of 750MPa is as follows. A steel material of a slab, comprising C 0.15-0.19 weight%, Si 0.25-0.35 weight%, Mn 1.05-1.15 weight%, P less than 0.03 weight%, S less than 0.015 weight%, V 0.27-0.32 weight%, Ti 0.06-0.08 weight%, Nb 0.015-0.025 weight%, N 0.008-0.013 weight%, Fe, and inevitable impurities, is reheated(S100). The reheated steel material is hot-rolled(S200). The hot-rolled steel material is cooled(S300).</p> |
