Strips of a spheroidized 0.68% C, 0.67% Mn and 0.24% Si pearlitic stee
l were submitted to rapid heat cycles. The samples were heated by dire
ct electrical conduction up to a peak temperature and immediately wate
r quenched. The morphological features of the alpha --> gamma transfor
mation were studied by light and electron microscopy It was found that
austenite at an early stage of the transformation has a specific lath
-like morphology and that its growth always starts directly a grain bo
undary of ferrite. Moreover, the presence of retained austenite allows
the prediction of relatively high carbon content in the transformatio
n product. The particular interaction of austenite laths with carbide
particles gives an indication that the growth mechanism can be displac
ive at its early stage. Comparing the morphological characteristics of
austenite formation observed in this study with those reported for au
stenite decomposition, a bainitic model of the early stage of alpha --
> gamma transformation is proposed. (C) 1998 Acta Metallurgica Inc. Pu
blished by Elsevier Science Ltd All rights reserved.