In this study we focus on the parameters affective on hot deformation of ductile iron GGG40 in different open die forging condition. after casting ductile iron and anneal heat treatment,obtain ductile iron with 95% spherical graphite and matrix microstructure more than 95% ferritic went under hot forging process. this process under strain rate less than 2S -1 got completed by hummer forge machine in the temperate range 800°C-1050°C and with reduction area sectio10%,20%,35%,50% and 65%. change in microsteructure and mechanicalroperties of forged sample were studied by doing metallography and making impact and tensile test. considering the graphite softness different and matrix ductile iron the ratio of deformation graphite to matrix(K) is presented in this approach. in present model changes graphite shaping factor (?) and K considering the forging process condition would be predictable. also maximum toughness(8J) and maximum strength (460MPa) are gained in deformation present of 20% to 35% in 950°C ,and deformation present 20% in temperature range 850°C to 950°Crespectively.