Journal of Advanced Materials in Engineering (Esteghlal)

In the present research, an effective thermo-mechanical processing route in the temperature range of metastable austenite region (Ae₃<T< Ar₃) was employed to achieve ultra-fine grain size in a plain low carbon steel during integrated extrusion equal channel angular pressing. At first, the effect of preheating temperature on the strain and temperature distributions inside the deformed samples were investigated using 3D finite element simulation. According to the result of FEM simulation, the preheating temperature of 930 ˚C was selected as an appropriate temperature for fabrication of ultra-fine ferrite structure. Severe plastic deformation was then imposed on samples with the predicted preheating temperature and the results showed a great consistency with FEM simulation predictions. Optical micrographs taken from the center point of the  samples showed that the ferrite grains could be refined from 32 &mu;m to 1-3 &mu;m by different mechanisms.