The workers barely speak between the metallic noises resounding amid the hiss of gas at the GHM foundry in Sommevoire. 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. Techniques have hardly changed since the first third of the 19th century. Founded in 1857, the factory perpetuates the tradition of the region's foundries.