Source : Webster's Revised Unabridged Dictionary (1913)

Crucible steel \Cru"ci*ble steel\
   Cast steel made by fusing in crucibles crude or scrap steel,
   wrought iron, and other ingredients and fluxes.

Source : WordNet®

crucible steel
     n : steel made by the mixture of molten wrought iron, charcoal,
         and other substances in a crucible