• severe plastic deformation;
  • multi-directional hot forging;
  • unidirectional hot forging;
  • Nb-microalloyed steel;
  • grain refinement

The microstructural and the tensile properties of Nb-microalloyed steel billet subjected to severe deformation processing were investigated. The steel samples in the form of as-cast were severely deformed using multi-directional hot forging process to approximately accumulated strain (∼4). The microstructure and tensile properties of multi-directional forging samples were compared with those of the unidirectional forging (UDF) samples. Both optical and scanning electron microscopy examinations showed that the grain size is smaller after multi-directional forging in comparison with UDF. In addition, the microstructure appears to be more homogeneous and generally more equiaxed after multi-directional forging processing.