In this way, the chill zone gives way to the columnar zone, consisting of grains elongated along the heat flow direction, which is close to one of their easy growth directions.

The grains in the columnar zone have different orientations from each other, because they are differently oriented in the plane normal to the heat direction.

The columnar zone may extend to the central plane of the casting. However, it often becomes possible for solids fragments (detached from growing dendrites by connection, or sedimenting from the free surface) to survive ahead of the advancing columnar grains. Such grain multiplication process can give rise to a central equiaxed zone, composed of randomly-oriented crystals.

Observe the simulation of how the growth occurs when liquid is poured into a mould.