The aim of the research work done in recent years was to check the possibilities of application of heat pipes in foundry technology. The possibility of influencing and controlling the thermal process in thermally exposed points in steel castings during soldification and cooling is indicated. The research covers the appliance of high temperature sodium and low temperature water heat pipes. The nature and results of experiments made with a sodium heat pipe in two different castings are described. The results of temperature measurements in the compound system "casting - chill - heat pipe - sand mould" are given. The paper is a follow-up of the results of the solution to the indirect thermal problem of heat transfer mentioned in |1|. More to properties of a sodium heat pipe can be found in |2|.