A novel processing technique for grain refinement has been developed. It involves the conditioning of liquid metal by intensive searing prior to casting. This technique is capable of establishing fine and uniform microstructures throughout the entire volume of the slabs. The microstructural refinement is attributed to the increased level of nuclei survival and enhancement of heterogeneous nucleation rates by well dispersed clusters, oxides or aluminides. Compared to chemical grain refinement, the MC process introduces physical refinement as an effective method and appears to have less adverse effects on the final mechanical properties. In practice a newly developed method (MC) for the continuous production of billets and slabs is introduced that is easily employable industrially and could be matched safely with other techniques to providing products of fine and uniform microstructures.