Formation conditions of coarse columnar austenite grain structure in peritectic carbon steels by the discontinuous grain growth mechanism

The discontinuous grain growth leading to a coarse columnar austenite grain (CCG) structure in as-cast peritectic carbon steels is analyzed by means of two- and three-dimensional phase field simulations. On the basis of the theory of grain growth, the conditions for discontinuous grain growth to occur are elucidated in terms of cooling conditions and material properties. The theoretical analysis explains the results of the phase field simulations well and should be useful in predicting the formation of CCG structure in continuously cast slabs.