DOUBLE-ANNEALED STEEL SHEET HAVING HIGH MECHANICAL STRENGTH AND DUCTILITY CHARACTERISTICS METHOD OF MANUFACTURE AND USE OF SUCH SHEETS

• Main Authors: HELL JEAN CHRISTOPHE, ARLAZAROV ARTEM, KEGEL FREDERIC
• Format: Patent
• Language: English; Korean
• Published: 17.11.2017
• 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

본 발명은 이중 소둔된 강판에 관한 것으로, 상기 강판의 조성은, 중량 퍼센트로, 0.20% ≤ C ≤ 0.40%, 0.8% ≤ Mn ≤ 1.4%, 1.60% ≤ Si ≤ 3.00%, 0.015% ≤ Nb ≤ 0.150%, Al ≤ 0.1%, Cr ≤ 1.0%, S ≤ 0.006%, P ≤ 0.030%, Ti ≤ 0.05%, V ≤ 0.05%, B ≤ 0.003%, N ≤ 0.01% 를 포함하고, 상기 조성의 나머지는 철 및 제조로부터 기인한 불가피한 불순물들로 구성되고, 미세조직은, 표면적 비율로, 10% ~ 30% 의 잔류 오스테나이트, 30% ~ 60% 의 소둔된 마텐자이트, 5% ~ 30% 의 베이나이트, 10% ~ 30% 의 새로운 마텐자이트 및 10% 미만의 페라이트로 구성된다. 본 발명은 또한 그 제조 방법 및 이러한 판의 용도에 관한 것이다. A double-annealed steel sheet is provided. The composition of which includes, expressed in percent by weight, 0.20%≤C≤0.40%, 0.8%≤Mn≤1.4%, 1.60%≤Si≤3.00%, 0.015≤Nb≤0.150%, Al≤0.1%, Cr≤1.0%, S≤0.006%, P≤0.030%, Ti≤0.05%, V≤0.05%, B≤0.003%, N≤0.01%. A remainder of the composition includes iron and unavoidable impurities resulting from processing. The microstructure of the steel sheet includes, in area percentages, 10 to 30% residual austenite, 30 to 60% annealed martensite, 5 to 30% bainite, 10 to 30% fresh martensite and less than 10% ferrite A fabrication method and vehicle parts are also provided.