Abstract: Molten metal, such as aluminum, is held within rigid refractory lining means beneath, above and alongside the metal while heaters keep the outside of the lining means at a predetermined temperature desired for the metal, the heaters being surrounded by thermal insulation and the whole being surrounded by a fluid-cooled support. An unusually effective embodiment is pipe, with a tubular refractory liner to carry flowing metal, surrounded by sheathed heating elements controlled to keep the exterior of the tube at least at about the predetermined temperature, with the thermal insulation wrapped around the heaters and the enclosing support being a water-jacketed steel pipe. The operation is essentially adiabatic with respect to the refractory liner, delivering the molten metal essentially at its original temperature, with unusual saving of heat energy. When the heated pipeline has been drained, only easily removed, paper-thin skulls of solid metal remain.