Abstract
The present work is concerned with the crystallographic aspects of Pearlite nucleation in three steels ; plain carbon, HSLA and Hadfield manganese steel. The results indicate two mechanisms for Pearlite formation, i. direct transformation of austenite into cementite and ferrite and ii, branching of ferrite to form Pearlite. The cementite-ferrite orientation exhibits the Pitsch relationship for the first mechanism and the Bagaryatskii one for the second. In addition, nucleation of ferrite from austenite is controlled by the Kurdjumov-Sacks relationship. In Hadfield steel transforming at 350°C, cementite precipitates at austenite lath boundaries. This indicates that such temperature is below the Pearlite transformation range. Furthermore, branching of ferrite in the same steel appears more dominant in the lower temperature range of pearlite formation.
