CRYSTALLOGRAPHIC STUDY OF PEARLITE GROWTH IN STEELS.

Abstract

The results show that the ferrite/cementite orientation is controlled by one of two relations, Pitsch or Bagaryatskii. The relation depends on the mechanism of nucleation either at clean austenite boundaries or on the pre-existing proeutectoid phase. The degeneration or spheroidization of cementite lamellae on reducing the transformation temperature is attributed to insufficient diffusion of carbon to maintain lamellar shape. This process has no influence on the lattice relationship. The interlamellar spacings are almost constant, despite the change in pearlite morphology.