Question

The permeability _________ with the grain size.

(a) Remains same

(b) Increases

(c) Decreases

(d) Depends on the sand

I had been asked this question by my school principal while I was bunking the class.

My doubt stems from Types of Sand Moulds in section Pattern Materials & Moulding Sand Tests of Foundry and Forging

Answer 1

Right choice is (b) Increases

For explanation: The grain size increases with the coarse grains. The coarse grains would have more void space between the grains which increases with permeability. Similarly, the finer grains would have lower permeability.