The effect of rolling with 15% ~ 40% and cooling rate 0. 8 °C/s and 1.2 °C/s in dual phase rigon on deformation-induced ferrite transformation in SCM435 cold-headed steel is studied by thermal simulation test. The results show that rolling of SCM435 steel in the austenite and ferrite two-phase zone (750 ~ 850 °C)，at a cooling rate of 0.8 °C/s

with amount of deformation increasing

the deformation-induced ferrite volume fraction increases

and there is a granular pearlite structure

and the hardness first decreases and then increases at a cooling rate of 1.2 °C/s

with amount of deformation increasing

the deformation-induced ferrite volume fraction decreases

and a granular bainite structure appears

and the hardness increases.