Casting pipes are used in industrial, chemical, and manufacturing processes to cool or transport molten metals and other liquids. The casting pipe is a closed vessel with a furnace and the casting liquid. The molten metal is poured into the furnace which melts the metal, and then the molten metal is cooled by a heat transfer fluid (often water). The heat transfer fluid flows through the bottom of the casting pipe into the liquid and then rises to the top where it is pumped back out of the top of the pipe to be reheated. The coolant is also used to control the temperature of the molten metal in the furnace.