High-strength steel with excellent durability and method for manufacturing same

A method of manufacturing a high-strength steel material having excellent durability, comprising:

• reheating a steel slab including, by weight, carbon (C):
• 0.05 to 0.15%, silicon (Si):
• 0.01 to 1.0%, manganese (Mn):
• 1.0 to 2.3%, aluminum (Al):
• 0.01 to 0.1%, chromium (Cr):
• 0.005 to 1.0%, phosphorus (P):
• 0.001 to 0.05%, sulfur (S):
• 0.001 to 0.01%, nitrogen (N):
• 0.001 to 0.01%, niobium (Nb):
• 0.005 to 0.07%, titanium (Ti):
• 0.005 to 0.11%, a balance of Fe, and other inevitable impurities, in a temperature within a range of 1200 to 1350° C.;
• hot-rolling the heated steel slab to prepare a hot-rolled steel sheet;
• cooling the hot-rolled steel sheet to a temperature within a range of 400 to 500° C. and then coiling (CT);
• and
• air-cooling to a temperature within a range of room temperature to 200° C. after coiling,
• wherein the hot-rolling includes finish hot-rolling performed at a temperature (FDT (° C.)) satisfying the following Relationship 1, and
• the cooling includes first cooling and second cooling, wherein the first cooling is performed at a cooling rate (CR1) satisfying the following Relationship 2, and the second cooling is performed at a cooling rate (CR2) satisfying the following Relationship 3:
• Tn−50 ≤FDT (hot-rolling end temperature (° C.)) ≤Tn [Relationship 1]
• where Tn=730+92×[C]+70×[Mn]+45×[Cr]+650×[Nb]+410×[Ti]−80×[Si]−1.4×(t−5) (where, an element refers to wt % of the element, and t refers to a thickness (mm) of the final hot-rolled steel sheet)
• CR1≥196−300×[C]+4.5×[Si]−71.8×[Mn]−59.6×[Cr]+187×[Ti]+852×[Nb] [Relationship 2]
• where an element refers to wt % of the element
• CRMin≤CR2≤CRMax [Relationship 3]
• where CRMax=76.6−157×[C]−25.2×[Si]−14.1×[Mn]−27.3×[Cr]+61×[Ti]+448×[Nb], CRMin=27.4−45.3×[C]+5.28×[Si]−11×[Mn]−7.33×[Cr]+42.3×[Ti]+82×[Nb] (where, an element refers to wt % of the element).