be accommodated in one of the voids with some slight distortion of the lattice.
Carbon thus has a higher solubility in austenite than in ferrite. Thus when iron
containing carbon is cooled from the austenitic state to the ferrite state, the
reduction in the solubility of carbon in iron means that some carbon must come
out of solution. This is achieved by the formation of
a
compound between iron
and carbon called cementite. This has one carbon atom for every three iron
atoms, hence it is often referred to as Fe
3
C (iron carbide).
11.2 Plain carbon steels
Figure 11.1 shows the iron-carbon system thermal equilibrium diagram.
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month, and much more.