EFEITO DO GRÃO ULTRAFINO NO COMPORTAMENTO MECÂNICO DO AÇO Nb-Ti DE LAMINADO A MORNO

The grain size refining is the unique mechanism capable of to increase both mechanical strength and toughness. In this way the refining of ferritic grain is a very attractive processing. The steel with an ultra-fine ferritic grain structure shows the better relationship between mechanical strength, ductility and toughness, while the low carbon content enhances good welding characteristics. The objective of this work is to investigate the behavior of work hardening of a micro alloyed low carbon-manganese (0.11C-1.41Mn-0.028Nb-0.012Ti) steel with ultra-fine ferritic grain structure produced through thermal treatment, warm rolling, followed by sub and intercritical annealing. After quenching in ice brine, the samples was processed by warm rolling and annealing. The mechanical behavior of the steel was estimated using tensile and impact tests. The mechanical strength obtained after all processing have shown a 15% increasing when compared with results from the steel in as hot rolling industrial condition.