Steel having high strength and large ductility and method for manufacturing the same

摘要

A steel plate according to the invention includes 1.0 to 1.4 wt.% of carbon; 5.0 to 9.0 wt.% of manganese; 2.0 to 8.0 wt.% of chromium; remaining iron and inevitable impurities. The steel plate according to the invention forms an austenite structure at room temperature and the stacking fault energy is effectively controlled with addition of chromium and nitrogen. The steel plate therefore has high work hardening and tensile strength and excellent machinability as mechanical twin occurs during plastic deformation of steel.