Pig iron is iron with a high carbon content. Pig iron is made by smelting iron ore into ingot form, in a blast furnace. It’s called pig iron because when being cast, each ingot being cast looks like a Piglet suckling milk from a sow.
Ancient Egyptians, Greeks, and Chinese knew about pig iron, and were producing it as early as 1100BC.
Pig iron is refined into Wrought iron by melting it and blowing hot air through it. Pig iron can also be turned into gray iron.
Originally, pig iron was poured out the bottom of the furnace and shipped to a steel mill for processing. Now, we turn the metal into pellets before shipping it.