Skip to main content
Article thumbnail
Location of Repository

Fe, C 3.6, Si 2.1 (wt%), hypereutectic grey cast iron

By University of Cambridge DoITPoMS and University of Cambridge Department of Materials Science and Metallurgy Prof T W Clyne


The carbon equivalent of this alloy (4.37 wt%) is greater than the eutectic composition (4.3 wt% C) so this alloy is known as a hypereutectic grey cast iron. Si has a very low solubility in cementite and therefore its presence favours the formation of graphite in preference to cementite. Therefore, upon cooling from the liquid, the primary phase to solidify is free graphite. Graphite forms directly from the melt as flakes (black) rather than dendrites. These flakes are interconnected and align themselves in the heat flow direction. Upon further cooling the remaining liquid forms initially as a eutectic mixture of austenite and cementite, known as ledeburite. The austenite within the eutectic further transforms to a mixture of pearlite and cementite. The graphite is eventually embedded in a complex mixture known as 'transformed ledeburite'. The graphite flakes are very soft and have low density so compensate for freezing contraction upon solidification, however they also act effectively as cracks making the cast iron is brittle.

Topics: alloy, carbon, cast iron, graphite, hypereutectic, iron, metal, silicon, doitpoms, university of cambridge, micrograph, corematerials, ukoer, Engineering, H000
Publisher: University of Cambridge
Year: 2010
OAI identifier:
Provided by: Jorum Open
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • (external link)
  • Suggested articles

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.