carburise

/ˈkɑːrbjəraɪz/
verb
  1. To add carbon to the surface of a metal (especially iron or steel) to make it harder.
    • You can carburise a knife blade to improve its edge retention.
    • Blacksmiths used to carburise iron by heating it with charcoal.
    • The factory uses a special furnace to carburise steel gears for heavy machinery.
Synonyms
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