Steel
Carbon deliberately added to iron produces a metal that holds an edge.
- When
- —
- Duration
- 500 years
- Known to
- ± 200 years
- Era
- Iron Age, Holocene
Carburising iron in a charcoal fire and then quenching it produces steel, which is harder than bronze and can be sharpened to an edge bronze cannot hold. The process is developed across the Near East, India and China in the first millennium BCE, and Indian wootz crucible steel becomes a famous export traded as far as Damascus. Making it consistently required judgement no one could yet explain, so it remained a craft secret rather than a technique.