| 摘要 |
<p>The present invention relates to a hot rolled steel capable of ensuring strength, impact, and a low yield ratio by controlling a finish rolling temperature and a coiling temperature while having high impact properties by controlling the content of niobium, molybdenum, and chrome, and having high strength based on a low carbon component; and a method of manufacturing the same. According to the present invention, the method of manufacturing the hot rolled steel comprises: a step of re-heating a steel slab comprising 0.07-0.11 wt% of carbon (C), 0.03 wt% or less of silicon (Si), 1.2-1.4 wt% of manganese (Mn), 0.015 wt% or less of phosphorus (P), 0.005 wt% or less of sulfur (S), 0.005-0.015 wt% of niobium (Nb), 0.01-0.02 wt% of chrome (Cr), 0.01-0.2 wt% of molybdenum (Mo), and the remainder consisting of Fe and inevitable impurities at 1140-1200°C which is a slab reheating temperature (SRT); a step of hot rolling the re-heated slab at 840-880°C which is a finishing delivery temperature (FDT); and a step of coiling the slab after cooling the hot rolled slab.</p> |
