Accelerated spheroidization of hypoeutectoid steel by the decomposition of supercooled austenite

Abstract

A thermal cycling treatment was used to produce a spheroidized structure of hypoeutectoid steel from direct decomposition of supercooled austenite. Scanning electron microscopy and quantitative metallography were employed to study the changing microstructure during the thermal cycling treatment. A conventional spheroidizing annealing was also investigated for comparison. It has been shown that the thermal cycling treatment results in a structure of cementite spheroidites homogeneously distributed in a ferrite matrix within a very short processing time, and the coarsening of cementite particles is controlled by the coupled diffusion of both carbon and iron atoms.