General
Transformations in steels

Between – 273°C and 912°C on the one hand, and from 1,394°C to 1,538°C on the other, the crystalline structure of pure iron is cubic-centered (CC) (this structure is not compact); in this state, the iron atoms occupy the vertices and center of a cube whose edge, at 20°C, measures 0.2866 nm (0.286 nm at – 273°C, 0.2903 nm at 912°C, 0.293 nm at 1,394°C).

Between –273°C and 912°C, the crystalline form of iron is known as "iron $\alpha$...