| For the high-silicon nodular irons, high-temperature heat treatment is advised in all cases to anneal any pearlite and stabilize the casting against growth in service. |
| Several other ingredients of importance, as pearlite, illustrated on the opposite page, have also been studied. |
| It is important to note that higher silicon contents can promote pearlite and may increase the nickel requirement. |
| The harder pearlite is comprised of alternating thin layers or shells of ferrite and cementite, a very hard substance. |
| Ductility and impact properties are principally determined by the proportions of ferrite and pearlite in the matrix. |
| The structure is illustrated in Fig.4 from the Cast Iron article which shows the structure of the phosphide eutectic, together with graphite, ferrite and pearlite. |
