Aluminum nitrides in carbon steel

1. An electron microscopic study of 08Yu steel with different concentrations of aluminum and nitrogen made it possible to determine the shape and size of the nitride phase in relation to the heat treatment, its distribution in the bulk of the solid solution, and its crystallographic nature. 2. The dispersed inclusions of aluminum nitride are platelets and rods, the latter occurring after tempering. 3. The nitride phase is distributed through the bulk of the ferrite grains. 4. The nitride phase has a hexagonal lattice witha=3.11 A, c=3.98 A. 5. The uneven distribution of the nitride phase through the bulk of the metal observed in the electron microscope is responsible for substantial differences in grain size. The grains are larger in sections with few aluminum nitrides. 6. The solution of the nitride phase at elevated temperature promotes austenite grain growth.