Mould with roughened surface for casting metals

摘要

A mold for casting metals is provided with a roughened surface so that, on first contact of the mold with the melt, heat transfer is controlled in such a way that the melt comes into contact only with the peaks of the projections on the mold surface and an air gap is formed between the melt and the valleys on the surface. The pattern of roughness on the mold surface comprises a uniform arrangement of pyramidal or blunted-cone shaped projections. Neighboring projections are spaced a distance d of 0.05 to 1 mm apart and have a height h of 0.1d<h<d. The pyramid or blunted con surfaces satisfy the condition of 0.05<f/d2<0.5. A process which does not involve deformation is preferred for producing the rough pattern, for example, a photochemical etching process. The molds are suitable for many casting processes, in particular for continuous D.C. ingot or strip casting with moving molds and caterpillar track type mold belts.