Microstructure and Mechanical Properties of ULCB Steels Affected by Advanced TMCP Technology
Good combination of high strength and high toughness has been considered as a critical factor of ultra-high strength steel plates. In this paper, a novel high strength steel plate of HSLA type containing Cu with 910MPa yield strength and 1163MPa tensile strength has been developed using an advanced TMCP (thermo-mechanical control processing) technology. The steel plates provide excellent combination of high strength, toughness and deformability. Microstructural evolution and mechanical properties of this steel during hot-working have been investigated. It is demonstrated that, at the relatively higher finish rolling temperature and cooling rate, the microstructure consists of acicular and granular bainite structures and a small amount of low bainite /martensite whose lath width is approximately 200~300nm. For the as-rolled conditions, despite the high strength and so low yield ratio, impact energy about 154J and fully ductility fracture at -90°C can still be obtained as documented for as-hot rolled plates.
Enhou Han, Guanghong Lu and Xiaolin Shu
Z. Y. Hou et al., "Microstructure and Mechanical Properties of ULCB Steels Affected by Advanced TMCP Technology", Materials Science Forum, Vol. 689, pp. 289-295, 2011