HIGH STRENGTH STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

摘要

Disclosed is a method to manufacture a lightweight high strength steel sheet having excellent strength and flexibility. According to the present invention, the high strength steel sheet comprises: 10.0-15.0 wt% of manganese (Mn); 6.0-9.0 wt% of aluminum (Al); 0.5-2.0 wt% of chrome (Cr); 0.8-1.6 wt% of carbon (C); 0.02-0.1 wt% of vanadium (V); 0.005-0.015 wt% of niobium (Nb); 0.005-0.02 wt% of molybdenum (Mo); 0.001-0.01 wt% of nitrogen (N); and the remaining comprising iron (Fe) and inevitable foreign substances. The method includes a step of manufacturing a hot rolled high strength steel sheet from a steel slab and then thermally treating the same in a reducing atmosphere at 850-950°C for 30 minutes to an hour.