Cooling element for metallurgical furnaces, esp. blast furnaces - using steel tubes coated with aluminium suspended in silicone lacquer, and then embedded in casting

摘要

Steel tubes are cleaned, and are then coated on their external surfaces with a silicone lacquer contg. a fine dispersion of Al powder. The coated tubes are dried, and are placed in a foundry mould, so that a casting can be made in which the tubes are embedded. The properties of the tubes are unaffected, but they have an external coating of Fe(x)Al(y), which is thin, brittle, and has good thermal conductivity. The bores of the steel tubes may be coated with a silicone lacquer, in which case the tubes are pref. cooled during the casting operation. The Fe-Al coating provides good heat transfer between a cast iron element, e.g. a plate, and cooling water circulating through the tubes embedded in the element. The coating prevents the carburisation and embrittlement of the tubes during the casting of the element. The thermal stress created by cooling a furnace produces fissures in the brittle Fe-Al coating to compensation for differences in thermal expansion.