The higher heat of steel when cast requires that (1) particular attention be paid to the venting of moulds, and that (2) the mould surfaces be especially treated to prevent washing away, or "scabbing," when metal is poured into them, and to prevent fusing in contact with the highly heated metal. The greater shrinkage of cast steel requires (1) that large feeding heads be attached to the heavy parts of a casting to prevent shrinkage cavities in the casting, and (2) that cores and moulds be composed of materials which will crush readily or which can be dug out to avoid shrinkage cracks.

Steel moulds are rammed up harder than iron or brass moulds.