Cold rolled steel sheet having excellent dent resistance property galvanized steel sheet and method of manufacturing the same

• Main Authors: HUH SUNG YUL, YU HA YOUNG, JANG MIN HO, PARK YOUNG JOO, KANG CHUN KU, HAN SEONG KYUNG, KIM BYOUNG JIN
• Format: Patent
• Language: English; Korean
• Published: 06.07.2022
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The present invention provides a dent-resistant cold-rolled steel sheet having an excellent dent-resistant property. According to one embodiment of the present invention, the dent-resistant cold-rolled steel sheet comprises 0.005-0.03 wt% of carbon (C), 1-2.5 wt% of manganese (Mn), 0.2-0.8 wt% of aluminum (Al), 0.3-1.5 wt% of the sum of chromium (Cr) and molybdenum (Mo), 0.001-0.01 wt% of the sum of niobium (Nb) and titanium (Ti), 0-0.02 wt% (excluding 0 wt%) of phosphorus (P), 0-0.01 wt% (excluding 0 wt%) of sulfur (S), and the remainder consisting of iron (F) and inevitable impurities. The dent-resistant cold-rolled steel sheet satisfies yield strength of 195 MPa or higher, tensile strength of 340 MPa or higher, elongation (El) of 33% or higher, and bake hardening (BH) of 40 MPa or higher. 본 발명은, 우수한 내텐트 특성을 가지는 내텐트성 냉연강판을 제공한다. 본 발명의 일 실시예에 의하면, 상기 내텐트성 냉연강판은, 중량%로, 탄소(C): 0.005% ~ 0.03%, 망간(Mn): 1.0% ~ 2.5%, 알루미늄(Al): 0.2% ~ 0.8%, 크롬(Cr)과 몰리브덴(Mo)의 총합: 0.3% ~ 1.5%, 니오븀(Nb)과 티타늄(Ti)의 총합: 0.001% ~ 0.01%, 인(P): 0% 초과 ~ 0.02%, 황(S): 0% 초과 ~ 0.01%, 및 잔부는 철(Fe)과 기타 불가피한 불순물을 포함하고, 항복강도(YP): 195 MPa 이상, 인장강도(TS): 340 MPa 이상, 연신율(El): 33% 이상, 및 소부 경화량(BH): 40 MPa 이상을 만족한다.