Forged iron is produced in a very furnace stoked with alternate layers of coking iron then poured into molds. Following the iron cools off, the sand is cleaned off. The Chinese were the 1st to work with Forged iron[1] through the sixth century AD employing it as support for pagodas https://www.cylex.us.com/company/naddour%27s-custom-metalworks-9223264.html