Metallurgy morphed from a predominance of bronze to widespread use of iron, specifically steel. Unalloyed iron is barely harder than bronze. Like tin to copper in making bronze, carbon acts as a hardening agent in rendering the alloy steel.
While bronze was cast, iron and steel are hammered into shape by blacksmiths: a reversion in technique for cobbling copper, but with a more durable material.
Like the Bronze Age, the Iron Age has low chronological value, as its advent temporally varied across societies.
The first known working of iron was in ancient Egypt ~3200 BCE, long before the declared Iron Age. Egyptian metal workers mastered the smithing of iron found in meteorites, using techniques that came to define the technical skills of the Iron Age. This knowledge was largely lost for over a millennium. In the meantime, the properties of iron went unappreciated. Iron was then worked in India beginning ~1,800 BCE.
Technology diffused at the pace of trade. Iron works appeared in Anatolia, Greece, and parts of Africa about 1300 bce. Centuries passed before iron-working technology reached central Europe, and, even later, northern Europe.
The adoption of iron coincided with material constraints and societal changes. A shortage of tin and trade disruptions in the Mediterranean forced metalworkers to seek an alternative to bronze.
Steel quality improved as iron became more available. Even as tin supplies later returned, bronze was largely shunned in light the cheaper, stronger, lighter, and more easily worked steel.
One account has the Iron Age ending in 586 BCE, with the destruction of the Temple in Jerusalem, after the city’s conquest by the Babylonian army under Nebuchadnezzar in 597 BCE. Other tabulation has the Iron Age ending with the fall of the western Roman Empire in 476 CE, at the onset of the barbarian chaos in western Europe that ushered in the Dark Ages. At any rate, the Iron Age ended with savagery.