Malleable cast iron by annealing
Fundición maleable por recocido del hierro colado
- Date
- c. 400-300 BCE · confidence medium
- Place
- Yan Xiadu, Yixian, Hebei, China
- Credited to
- Blacksmiths of the Warring States period (State of Yan)
- Field
- Matter & energy
What it is
Prolonged heat treatment of cast iron pieces to decarburise their surface and make them less brittle. It made mass-cast agricultural tools usable.
Europe did not develop malleable cast iron until Réaumur (1722).
What it led to
- cheap, sturdy agricultural tools produced in mass
- state monopoly on iron in the Han dynasty
- expansion of cereal farming