Mechanical properties of a quenched and tempered dual phase steel

The mechanical properties of a heat treated dual phase steel were investigated as a function of the martensite volume fraction. The changes promoted by tempering at 100 °C, 200 °C and 300 °C were measured and investigated. Residual stresses introduced by quenching from the intercritical temperature and the changes occurred during the tempering were also measured. In the as quenched condition the samples with higher martensite volume fraction presented higher toughness but a still brittle behaviour. Toughness was raised by the tempering treatment at 200 °C and at 300 °C. The yield and ultimate strength decreased linearly with the tempering treatment, in the range of 100 °C to 300 °C.