Abstract: The invention provides a method and a set-up for production of castings containing cast-in steel tubes, preferably to provide cooling elements for metallurgical furnaces. The castings are from cast steel and the steel tubes are cast-in with a superheated cast steel melt. Before the casting the tubes are filled with a granular, highly thermal conductive, refractory material. In order to assure that the cast-in steel or respectively cooling tubes remain free from leaks, the invention provides to employ as a filling material one or more of the materials: burned magnesite (sintered magnesite), corundum, sintered aluminum oxide, chromite, silicon carbide, silicon nitride.