The influence of hot deformation on the incubation period of ferrite transformation was calculated to determine the onset of deformation induced transformation. Temperature A r3d depends on deformation condition and alloying composition, and decreases with increasing carbon content. When deformation induced ferrite transformation occurs, the flow curves of dislocation density will show strong softening characteristic. Through temperature heavy deformation, ferrite transformation is enhanced and more volume fraction is obtained. The simulated results are in good agreement with the experiment ones. The influence of hot deformation on the incubation period of ferrite transformation was calculated to determine the onset of deformation induced transformation. Temperature A r3d depends on deformation condition and alloying composition, and decreases with increasing carbon content. When deformation induced ferrite transformation occurs, the flow curves of dislocation density will show strong softening characteristic. Through temperature heavy deformation, ferrite transformation is enhanced and more volume fraction is obtained. The simulated results are in good agreement with the experiment ones.