Discontinuous transformation in the steel under hot deformation conditions

Purposeful effect of hot deformation process and transformation – austenite (A) to ferrite (F) and to pearlite (P) – interaction on the carbon steel microstructure was studied. Hot compression tests at various strain rates were performed during controlled cooling of the sample within the temperature range related to the start and finish of the phase transformation. Attention was paid to structural effects of dynamic precipitation and resulted morphology of structural components depended on expected localisation of phase transformation. The findings of carbide precipitates development along ferrite grain boundaries was the most noticeable effect of the hot deformation and subsequent transformation for tested samples. However, the flow localisation and preferred growth of the discontinuous transformation product-pearlite at shear bands was very limited. [Received on 25 October 2006; Accepted on 21 February 2007]