text: Types and shapes Bar iron is a generic term sometimes used to distinguish it from cast iron.  It is the equivalent of an ingot of cast metal, in a convenient form for handling, storage, shipping and further working into a finished product.
  The bars were the usual product of the finery forge, but not necessarily made by that process:
  Rod iron—cut from flat bar iron in a slitting mill provided the raw material for spikes and nails.
  Hoop iron—suitable for the hoops of barrels, made by passing rod iron through rolling dies.
  Plate iron—sheets suitable for use as boiler plate.
  Blackplate—sheets, perhaps thinner than plate iron, from the black rolling stage of tinplate production.
  Voyage iron—narrow flat bar iron, made or cut into bars of a particular weight, a commodity for sale in Africa for the Atlantic slave trade. The number of bars per ton gradually increased from 70 per ton in the 1660s to 75–80 per ton in 1685 and "near 92 to the ton" in 1731.
  Origin
  Charcoal iron—until the end of the 18th century, wrought iron was smelted from ore using charcoal, by the bloomery process. Wrought iron was also produced from pig iron using a finery forge or in a Lancashire hearth. The resulting metal was highly variable, both in chemistry and slag content.