Abstract A 50 kg-grade cold rolled dual phase (DP) steel was developed based on the orthogonal design method. The intercritical annealing, aging and galvanizing temperatures during the heat treatment were considered as controllable factors and three levels for each of these factors were selected. The optimal experimental conditions were acquired by the analysis of variance (ANOVA) on the ultimate tensile strength (UTS) and the total elongation of the DP steel. A dilatometry analysis was performed to measure the phase transformation kinetics of the DP steel and to verify the statistically analyzed results. These metallurgical observations explained well the statistically analyzed results.