A method for keeping melt in a blind riser hot during casting operations, and a product for doing this.

摘要

When casting materials by feeding melt into a mould (5), such as metal into a sand mould, there can be problems of internal quality of the cast product due to cavities caused by shrinkage upon cooling and solidification. It is known, therefore to provide blind risers (2) which act as a head or reservoir to feed melt to the product: it is desirable to keep melt within the riser hot and liquid for the whole time that the cast product is solidifying and shrinking. The invention comprises a method for keeping melt within a riser hot during the product solidification stage by providing a pre-formed body (3a) of an exothermic composition which can be positioned in the riser or in a cavity or channel communicating with the riser and which will float or be suspended in the melt in the riser and give out heat to keep the melt in the riser liquid, and in another aspect the invention provides a product for carrying out the method.