LOW-DENSITY HOT- OR COLD-ROLLED STEEL, METHOD FOR IMPLEMENTING SAME AND USE THEREOF

摘要

The invention relates to a sheet of rolled steel having mechanical strength no lower than 600 MPa and elongation at break no lower than 20 % as well as to the method for manufacturing same. The chemical composition of the sheet of the invention includes: 0.10 % <= C <= 0.30 %, 6.0 % <= Mn <= 15.0 %, 6.0 % <= Al <= 15.0 %, and optionally one or more elements selected among: Si <= 2.0 %, Ti <= 0.2 %, V <= 0.6 % and Nb <= 0.3 %, the rest of the composition comprising iron and inevitable impurities that result from the production process. The weight ratio of manganese to aluminium is such that: (I). The microstructure of the sheet according to the invention consists of ferrite, austenite and up to 5 % of kappa precipitates as a surface fraction.