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: / > 1.0. The microstructure of the sheet according to the invention consists of ferrite , austenite and up to 5 % of kappa precipitates as a surface fraction.