METHOD FOR PRODUCING Austenitic Iron / Carbon / Manganese Steel Sheets Having Very High Strength and Elongation Characteristics, And Also Exceptional Uniformity

摘要

1. Hot rolled austenitic iron / carbon / manganese steel sheet, the tensile strength of which has a value greater than 1200 MPa, the product P (strength in (MPa) × elongation at break (in%)) which has a value greater than 65000 MPa% and the nominal chemical composition of which includes, wt.%: 0.85% ≤С≤1.05%; 16% ≤Mn≤19%; Si≤2%; Al≤0.050%; S≤0.030%; Р≤0.050%; N≤0.1% ; and, if necessary, one or more elements selected from: Cr≤1%; Mo≤1.50%; Ni≤1%; Cu≤5%; Ti≤0.50%; Nb≤0.50%; V≤0.50%; rest iron and inevitable impurities resulting from fusion, recrystallized surface the spacing of said steel is 100%, the surface of the deposited carbides of said steel is 0%, and the average grain size of the steel is less than or equal to 10 μm. 2. Cold rolled and annealed austenitic iron / carbon / manganese steel sheet with a tensile strength greater than 1200 MPa, product P (tensile strength (MPa) × elongation at break (%)) of more than 65000 MPa% and nominal chemical the composition of which includes, wt.%: 0.85% ≤С≤1.05%; 16% ≤Mn≤19%; Si≤2%; Al≤0.050%; S≤0.030%; P≤0.050%; N≤0.1%; and optionally one or more elements selected from: Cr≤1%; Mo≤1.50%; Ni≤1%; Cu≤5%; Ti≤0.50%; Nb≤0.50%; V≤0.50%; the rest is iron and optional impurities, recrystallized surface resulting from fusion the aforementioned steel is 100%, the surface of the precipitated carbides of said steel is 0% and the average grain size of said steel is less than or equal to 5 mkm.3. The cold-rolled and annealed steel sheet according to claim 2, the tensile strength of which matters more than 1250 MPa, the product P (tensile strength (MPa) × elongation at break (%)) of which