METHOD FOR PRODUCING A ULTRA HIGH STRENGTH COATED OR NOT COATED STEEL SHEET AND OBTAINED SHEET

• Main Authors: PANAHI DAMON, GIRINA OLGA A
• Format: Patent
• Language: English; Korean
• Published: 08.03.2017
• Subjects: ALLOYS; APPARATUS THEREFOR; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

인장 강도 ≥1470 MPa 및 총 연신율 (TE) ≥19% 를 갖는 냉간 압연된 강 시트를 제조하기 위한 방법으로서, 상기 방법은 어닐링 온도 (AT) ≥Ac3 에서 비처리된 강 시트를 어닐링하는 단계로서, 상기 강의 화학적 조성은 중량 % 로: 0.34 % ≤C ≤0.40 %, 1.50 % ≤Mn ≤2.30 %, 1.50 ≤Si ≤2.40%, 0 % < Cr ≤0.7%, 0 % ≤Mo ≤0.3 %, 0.01 % ≤Al ≤0.07 % 를 포함하고, 잔부는 Fe 및 불가피 불순물들인, 상기 비처리된 강 시트를 어닐링하는 단계, 150 ℃ 내지 250 ℃ 인 켄칭 온도 (QT) < Ms 변태점로 어닐링된 강 시트를 냉각함으로서 어닐링된 강 시트를 켄칭하는 단계, 및 350℃ 내지 420℃ 의 파티셔닝 온도 (PT) 로 켄칭된 강 시트를 재가열함으로서 파티셔닝 처리를 행하고 15 초 내지 250 초의 파티셔닝 시간 (Pt) 동안 이러한 온도에서 강 시트를 유지하는 단계를 포함한다. A method for producing a cold rolled steel sheet having a tensile strength ≥ 1470 MPa and a total elongation TE ≥ 19%, the method comprising the steps of annealing at an annealing temperature AT ≥ Ac3 a non-treated steel sheet whose chemical composition contains in weight %: 0.34 % ≤ C ≤ 0.40 %, 1.50 % ≤ Mn ≤ 2.30 %, 1.50 ≤ Si ≤ 2.40%, 0 % < Cr ≤ 0.7%, 0 % ≤ Mo ≤ 0.3 %, 0.01 % ≤ Al ≤ 0.07 %, the remainder being Fe and unavoidable impurities, quenching the annealed steel sheet by cooling it to a quenching temperature QT < Ms transformation point and between 150 °C and 250 °C, and making a partitioning treatment by reheating the quenched steel sheet to a partitioning temperature PT between 350°C and 420°C and maintaining the steel sheet at this temperature during a partitioning time Pt between 15 seconds and 250 seconds.