Compacted Graphite

[blown54]

I post this to all of you due to the fact, I am just lost!
I am contemplating handling performance engine blocks and one aspect is that they advertise one of their blocks as being "CG" being lighter and stronger. Can any of you educate me? Thanks in advance,
Fred

 

[mcguire]

CG, or compacted graphite, iron is a cast iron in which the graphite phase is a rather imperfect version of the spherical graphie of nodular iron, which is strong and ductile rather than the long flake shape which is found in grey iron and which makes grey iron brittle.
The graphite in cast iron gives it its good thermal conductivity. In CG iron you get the graphite flakes giving good conductivity without being so long and interconnected that they hurt mechanical properties badly.

 

[metengr]

Here is a little more information to add;

CG irons have certain advantages over gray cast irons -
-higher tensile strength at the same carbon equivalent for gray cast iron
-higher ratio of tensile strength to hardness
-much higher ductility and toughness, higher safety margin against fracture
-lower oxidation and growth at high temperatures

compared to ductile irons, the advantages of CG irons are;
-lower coefficient of thermal expansion
-higher thermal conductivity
-higher dampening capacity
-better castability, higher yield and more intricate castings
-improved machinability

The information above was cited from the ASM Metals Handbook, Desk Edition, page 321

 

[TVP]

Sintercast are the leading manufacturers of CG iron parts. Check out their website for more information:

http://www.sintercast.com/