Redn. of heat losses from molten baths at high temp. - esp. salt baths for heat treating metals, using floating cover of lightweight corundum beads obtd. large savings in heating energy

摘要

Molten bath is provided with a floating cover, which consists of solid fragments resisting abrasion and possessing a density below 1.0. The fragments are refractory, with a m.pt. above 1800 deg.C., and are electrical- and thermal- insulators; the fragments also posses closed pores, and are inert w.r.t. the bath and workpieces treated in the bath. The pref. fragments consist of alumina, esp. light, electromelted corundum beads with dia. 2-5 mm. The fragments are pref. dried before use and sieved to remove fines; they pref. form a floating layer 1-3 cm thick. Savings in heating energy of up to 80% can be achieved.