Abstract
The influence of austenite grain size on ferrite banding has been investigated. Ferrite bands of annealed steels are largely influenced by the austenite grain size. When the annealing temperature is very high, the microstructure does not show a banded structure due to the diffusion of segregation and the grain growth. On annealing of the mixed grain structure, the region of fine grains is banded, but that of coarse grain is not. When fully annealed, fine grained steels show a banded structure, but coarse grained steels do not. The banded structure is extreamely influenced by the relation between the forging ratio, i.e. the width of segregation zones and the austenite grain size. With increase in grain size of austenite rather than in width of segregation zone, the banded structures are hardly distinguishable, and when reversed, the banded structure has the tendency to be clear. The mechanism of formation of the banded structure is also discussed.
