Steel

Smelting using wood never yielded iron because the flame wasn't hot enough. Charcoal, formed by burning wood with low oxygen, burned hot enough to melt iron. Initially too fragile, alloying with carbon yielded steel.
Hittite 1,000 BCE
Steel

Smelting using wood never yielded iron because the flame wasn't hot enough. Charcoal, formed by burning wood with low oxygen, burned hot enough to melt iron. Initially too fragile, alloying with carbon yielded steel.