Product Announcement from National Bronze & Metals Inc.
The tundish furnace maintains a large reservoir of molten metal at a controlled temperature above a water-cooled graphite die. Any dross entering the tundish furnace quickly floats to the top of the metal bath where it is removed.
Entrainment of slag in the cast bars is not possible. These features guarantee castings free of solid inclusion and porosity from gas or shrinkage.
Metal enters the freezing zone of the die (D) at a temperature in sufficient excess of the liquidus to assure that any shrinkage pores in prior cast material are filled. This is accomplished in a fraction of a second before rapid freezing begins. Severe segregation of alloying elements is thereby avoided. Special patented techniques further reduce segregation and greatly improve casting strength by generating a fine grain structure in the casting.
The newly frozen layer of metal shrinks rapidly away from the graphite die and is withdrawn from the die by a set of electrically driven pinch rolls.
As the newly solidified portion of the casting leaves the freezing zone, the die is gravity filled (E) with molten metal from the tundish. The solidification process then begins again.
When the casting has attained the desired length, it is cut off with a flying saw positioned below the pinch rolls.