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OwnerAstrid PERLADE, Kangying ZHU +2inventors
InventorsAstrid PERLADE, Kangying ZHU, Coralie JUNG, Frédéric KEGEL
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A method for manufacturing a hot rolled and heat-treated steel sheet includes casting to obtain a semi-finished product having a composition comprising, by weight percent: C: 0.12-0.25%, Mn: 3.0-8.0%, Si: 0.7-1.5%, Al: 0.3-1.2%, B: 0.0002-0.004%, S≤0.010%, P≤0.020%, N≤0.008%, and iron; reheating at a Treheat between 1150° C. and 1300° C.; hot rolling the reheated semi-finished product with a finish rolling temperature (Tnr-100° C. to 950° C.), coiling the hot rolled steel sheet at a Tcoil (20° C. and 700° C.) and cooling to obtain a microstructure comprising martensite and bainite, M+B>80%, F<20%, and <20% of the sum of martensite-austenite (M-A) islands and carbides, and having the multiplication of PAGS <1000 μm2 and a pancaking index <5; reheating, quenching, reheating to a partitioning temperature, holding for 1 to 1000 seconds, and cooling.
A method for manufacturing a hot rolled and heat-treated steel sheet, comprising the following successive steps:
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