**6. Effect of temperature gradient on the feeding range of the alloys**

As mentioned earlier the temperature gradient in a casting system can be made stiff from a shallow one by adopting several means. This is illustrated in **Figures 19** and **20** [16].

A stiff temperature gradient can reduce the extent of pasty zone with the associated advantages in setting of directionality in solidification. On the other hand, a shallow temperature gradient can be set up and extensive pasty zone resulting in simultaneous freezing in an extended zone in the melt and help distribution of micropores.

**Figure 19.** *Shallow temperature gradient showing extensive pasty zone.*

**Figure 20.**

*Effect of stiff temperature gradient on pasty zone (narrow zone of crystallisation).*
