냉간 압연되고 이중 어닐링된 강판

• Main Authors: PERLADE ASTRID, ZHU KANGYING, KEGEL FREDERIC
• Format: Patent
• Language: Korean
• Published: 06.01.2023
• Subjects: ALLOYS; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WELDING; WORKING BY LASER BEAM

본 발명은 냉간 압연되고 이중 어닐링된 강판에 관한 것으로서, 중량 백분율로, C : 0.03 - 0.18% Mn　: 6.0 - 11.0% 0.2 ≤ Al ≤ 3% Mo　: 0.05 - 0.5% B　: 0.0005 - 0.005% S ≤ 0.010% P　≤ 0.020% N ≤ 0.008% 및 선택적으로, 중량 백분율로, 다음의 원소들 Si ≤ 1.20% Nb　≤ 0.050% Ti ≤ 0.050% Cr ≤ 0.5% V ≤ 0.2% 중 하나 이상을 포함하는 조성을 가진 강으로 제조되고, 상기 조성의 잔부는 철 및 제련으로부터 기인하는 불가피한 불순물들이고, 상기 강판은, 표면 분율로, - 0% 내지 45% 의 페라이트, - 20% 내지 50% 의 잔류 오스테나이트, - 5% 내지 80% 의 어닐링된 마르텐사이트, - 5% 미만의 프레쉬 마르텐사이트, - 비 ([C]A2 x [Mn]A)/(C%2 x Mn%) 가 4.5 내지 11.0 이며, C% 및 Mn% 이 강 중 공칭 C 및 Mn 중량 백분율이도록, wt% 로 표현된, 오스테나이트 중 탄소 [C]A 및 망간 [Mn]A 함량, 및 - 4x106/㎟ 미만의 탄화물 밀도 를 포함하는 미세조직을 가진다. A cold rolled and double annealed steel sheet, made of a steel having a composition including, by weight percent: C: 0.03-0.18%, Mn: 6.0-11.0%, 0.2≤Al<3%, Mo: 0.05-0.5%, B: 0.0005-0.005%, S≤0.010%, P≤0.020%, N≤0.008%, and including optionally one or more of the following elements. In weight percentage: Si≤1.20%, Nb≤0.050%, Ti≤0.050%, Cr≤0.5%,V≤0.2%, the remainder of the composition being iron and unavoidable impurities resulting from the smelting, the steel sheet having a microstructure including, in surface fraction, from 0% to 45% of ferrite, from 20% to 50% of retained austenite, from 5 to 80% of annealed martensite, less than 5% of fresh martensite, a carbon [C]A and manganese [Mn]A content in austenite, expressed in wt %, such that the ratio ([C]A2×[Mn]A)/(C %2×Mn %) is from 4.5 to 11.0, C % and Mn % being the nominal C and Mn weight percent in the steel and a carbides density below 4×106/mm2.