Metallographic examination of breakouts from a continuous billet caster

The solidification of carbon and low alloy steels in the mould during continuous casting has been investigated by examination of solid shells of continuously cast billets that have been left in the mould after a breakout has occurred. The investigations show that steels containing less than 0.17 wt% C behave differently from steels with higher carbon content with respect to volume changes, heat transfer to the mould and formation of oscillation marks, so that each group requires casting parameters according to its own specific thermal and mechanical properties in order to obtain optimal casting conditions and quality of the cast product.