The effects of double intercritical annealing on microstructure and mechanical properties of 0.107C-2.39Mn-0.453Si dual phase steel

                In this study, double intercritical annealing was applied to modify the mechanical properties of 0.107%C-2.39%Mn-0.453%Si dual phase steel. The effects of the double intercritical annealing (DIA) method were investigated via microstructure observation and tensile test, and then compared with the single intercritical annealing (SIA) method. By increasing the intercritical annealing temperature, yield and tensile strengths increase while ductility decreases primarily due to the increase of martensite fraction. DIA leads to a slight reduction of the ferrite size and the martensite fraction regardless of the intercritical annealing temperature. Tensile results showed that DIA increases ductility without losing significant amount of strength. The outcome implies that the DIA method can be used to modify the mechanical properties of DP steels without adding excessive complexity to the process.