FERRIC LIGHTWEIGHT STEEL

The present invention relates to ferritic lightweight steel having decreased specific gravity and having excellent mechanical strength by suppressing formation of κ-carbide. According to an embodiment of the present invention, the ferrite lightweight steel comprises: 0.05-0.12 wt% of carbon (C); 3.0-7.0 wt% of aluminum (Al); an amount of less than or equal to 0.5 wt% (excluding 0 wt%) of manganese (Mn); an amount of less than or equal to 0.5 wt% (excluding 0 wt%) of nickel (Ni); an amount of less than or equal to 0.75 wt% (excluding 0 wt%) of chromium (Cr); 0.3-0.75 wt% of silicon (Si); 0.25-0.7 wt% of combined titanium (Ti) and vanadium (V); and the remainder consisting of iron (Fe) and other inevitable impurities. 본 발명은 κ-탄화물의 형성을 억제하여 강도를 우수하게 유지하면서 비중을 감소시킬 수 있는 페라이트계 경량강에 관한 것이다. 본 발명의 일 실시형태에 따른 페라이트계 경량강은 중량%로, C: 0.05 ~ 0.12%, Al: 3.0 ~ 7.0%, Mn: 0.5% 이하(0% 제외), Ni: 0.5% 이하(0% 제외), Cr: 0.75% 이하(0% 제외), Si: 0.3 ~ 0.75%, Ti+V: 0.25 ~ 0.7%, 나머지 Fe 및 기타 불가피한 불순물을 포함한다.