In metallurgy, cast iron describes an iron alloy containing 2.1 to 6.67% of carbon. The steelmakers at GHM, in the Haute-Marne department, also often work with cast aluminum and bronze alloys. They carry the molten metal at 2,550° F (1,400° C) in pockets called ladles and pour it into the mold through a cavity. When overflowing, the liquid mass stops as the vent is turned on to evacuate the gases. Techniques have hardly changed since the 19th century.