This study developing mathematical model to optimize heat treatment process to obtain the most significant parameter that affected tensile strength of duralium through multistage artificial aging. The process parameters in this study were temperature of aging, holding time of aging, and artificial aging process was conducted in double stages. The experiments were conducted according to central composite design matrix. The adequacy of developed model was analysed by analysis of variance (ANOVA). The optimum parameter of multistage artificial aging was obtained for maximum tensile strength of duralium. © The Authors, published by EDP Sciences, 2018.