Stack Annealing Furnace

a vertical drawing furnace for the continuous heat treatment of metal strip. The strip is drawn through one or several vertical passes by electrically driven rollers. In moving through the furnace, the strip passes through heating, soaking, and cooling chambers at various speeds; as a result, a complex sequence of heat treatment may be performed. The chambers of stack annealing furnaces are filled with a special atmosphere whose composition depends on the mode of thermal or thermochemical treatment.

Stack annealing furnaces are installed as components of flow lines, which in addition to the middle (furnace) section—the furnace itself—have head and tail sections. The head section of such a line includes uncoilers, shears for cropping ends, welding machines for welding the end of a coil to the beginning of the next coil, metal-cleaning devices, and looping devices, which store the strip to provide a continuous supply to the furnace during welding of ends. The tail section has an output looping device, a device for tensioning the strip, and coilers or a section for cutting the strip into sheets.