Chilled cast iron
Chilled cast iron is metastable cast iron with a high carbide content.
The metastable solidification leads to the formation of ledeburite ( austenite and cementite ), which is particularly hard and wear-resistant. Depending on the cooling rate or the wall thickness of the component, stable solidification and thus the formation of graphite in a matrix of ferrite and pearlite can also occur. Graphite is much more ductile than ledeburite.
In the case of thick components, this means that the surface layer consists of ledeburite and perlite, while the core consists of graphite, perlite and ferrite. This chilled cast iron (also known as chill cast iron ) has a ductile core and a hard shell. With solid chilled cast iron , the maximum cross-section may only be 100 mm so that predominantly hard Ledeburit is present in the component. In both cases, a hard surface layer (e.g. for camshafts ) is created.
The formation of chilled cast iron is achieved through a high silicon and manganese content or through rapid cooling in iron molds.
Chilled cast iron is used as a very wear-resistant cast material for grinding disks , ore crushers and military armor ( armor plates ). Chilled cast iron is very difficult to machine, practically only grindable and erodible.
Examples
- GJH - X 300 CrNi 9-5
Machinability
See machinability of cast iron # Chilled cast iron .
Individual evidence
- ↑ Chilled cast . In: Lexikon der Chemie , Wissenschaft-Online-Lexika; Retrieved January 5, 2009