Warmatrix

War Matrix - Iron weapons

Though iron working was probably invented as early as the 3rd millenium BCE, for a long time it remained marginal. The Hittites were the first to produce iron artifacts on a large scale, but iron working only really took off in the 12th century BCE. Iron working is much more difficult than the bronze working that preceded it, requiring much higher temperatures to smelt the ore.
Early iron was of poor quality, actually weaker than bronze. But iron ore is much more common than copper and tin and this allowed production of iron weapons and armor on a large scale. It was this, not the hardness of the metal, that revolutionized ancient warfare. Trade routes that exchanged copper and tin were disrupted and the supremacy of the chariot elite was toppled by large infantry armies armed with iron.
There are two variants of iron used in weapons. Wrought iron, with a very low carbon content, was the most common form in use since ancient times, using the blooming process to smelt iron ore. It is relatively soft, mallable and bends easily. The Chinese developed cast iron, with a high carbon content, in the 5th century BCE. This is the opposite of wrought iron: hard but brittle and prone to rust. Eventually weaponsmiths managed to produce iron with just the right amount of carbon: steel.