Effect of intercritical annealing temperature on microstructure and tensile properties of dual phase steel

Dual phase steels are modern steels with structural uses. They have better strength and formability than those of mild steels. In this research the effect of intercritical annealing temperature between 740 and 810 oC on microstructure and tensile properties of dual phase steel, prepared of primary ferritic pearlitic microstructure, was studied. Primary steel was annealed at four temperatures, and was subjected to tensile test, hardness test and SEM metallography test. The results showed that morphology and percentages of final phases were dependent on the annealing temperature, and had effects on the final properties of steel. The martensite vol.% was increased with increasing annealing temperature, hence the tensile strength was increased and the elongation was decreased. The good combination of strength and elongation in the steel can be achieved using the selection of suitable intercritical annealing temperature.