Acceleration of spheroidization in eutectoid steels by the addition of aluminum

A novel concept for accelerating spheroidization of high-carbon steels by the addition of aluminum has been proposed in this research. The spheroidization process can be defined as two stages: breaking cementite lamellae and coarsening cementite particles. Aluminum enhances the spheroidizing temperature by increasing the austenite starting temperature, and refines the interlamellar spacing. The relationship of the annealing temperature and the interlamellar spacing with the two spheroidization stages is first established, and the mechanism by which spheroidization is accelerated by the addition of aluminum is explained.