Effect of pressing temperature on microstructure and tensile behavior of low carbon steels processed by equal channel angular pressing

Two grades of low carbon steels, one containing vanadium and the other without vanadium, were subjected to equal channel angular pressing at a temperature range of 623–873 K. For steel without vanadium, the equal channel angular pressing at 623 K resulted in ultrafine (∼0.3 μm) ferrite grains with high angle boundaries. At higher pressing temperature, coarser grains with low angle boundaries were formed, which indicates that the recovery occurs at a significant rate during the pressing. For the steel containing vanadium, submicrometer order ferrite grains and high dislocation density were preserved up to pressing temperature of 873 K. The enhanced thermal stability of the steel containing vanadium was attributed to its peculiar microstructure consisted with fine ferrite grains with uniformly distributed nano-sized cementite particles. In addition, the tensile behaviors of the equal channel angular pressed steels were characterized and discussed based on the microstructure.