Guidelines for long ultrafine grained steel production and application to the automotive sector.

Resumen: In order to meet the increasing needs from economic and social developments in future, the research on new generation steels with higher strength and longer duration, has become a worldwide issue. It is well known that various mechanisms to strengthen the steels exist, but grain refinement is the only method to improve both strength and toughness simultaneously. A ferrite grain size in the range of 1÷4 um and a steel microstructure characterised by a mixture of ferrite-pearlite and/or martensite, bainite microstructure, could give a very good combination of mechanical (strength, ductility, toughness, fatigue) and technological properties (machinability, cold/warm metal forming, etc.) for final application to automotive components.