Cast Iron Castings

Terminology

• Flake Graphite Iron
• Flake Graphite Cast Iron
• Hematite
• Grey Cast Iron
• Gray Cast Iron
• Cast Iron

One of the first things that can cause confusion when discussing
cast iron, or attempting to source it, is the varied number of ways
it can be described. Because of its age and wide geographical
spread many terms, often local in nature, have grown up.
Cast iron, grey cast iron, gray cast iron, flake graphite iron
and flake graphite cast iron all refer to the same material.
The term grey is used because of the colour of the fracture
surface if a piece is broken.

Hematite can also be used and refers to cast iron with a specific application in castings subject to heating and cooling cycles or operating at elevated temperatures, such as forge furnace doors and arch plates. It is rather an old fashioned term, referring to cast iron with a high carbon content (4%), a low silicon content (1.6%) and low impurities.

An example of a Flake Graphite Cast Iron Casting from Durham Foundry

If molten cast iron is allowed to cool normally the carbon comes out of solution and forms flakes of graphite which run through the ferrite/pearlite matrix, hence the alternative term, flake graphite iron.

These flakes are at the microscopic level, the ends of which form stress points in the cast iron. Cast irons typically contain 2-4 wt% of carbon with silicon at 1.8-2.4 wt% and a greater concentration of impurities than steels. The carbon equivalent (CE) of a cast iron helps to distinguish the grey irons which cool into a microstructure containing graphite and the white irons where the carbon is present mainly as cementite. The carbon equivalent is defined as:

Please browse our website for more information about Flake Graphite Iron, Flake Graphite Cast Iron & Hematite from Durham Foundry and our ability to manufacture Engineering Cast Iron Castings to ISO 185 standards then contact us on 0114 249 4977 or e-mail us on castings@durhamfoundry.com.