Question

In the given below graph, which curve represents the permeability of the green sand mould with the % of the water content?

(a) a

(b) b

(c) c

(d) d

This question was addressed to me during a job interview.

This intriguing question originated from Green Sand Mould topic in division Pattern and Mould, Principles of Gating & Risering of Casting-Forming-Welding I

Answer 1

The correct answer is (c) c

The explanation: There is optimum water content for the permeability considerations. At a lower water content, dry clay powder, being finer than sand grains, fills up the voids between the sand particles, and thus reduces the permeability. Beyond the optimum water content, water itself fills up the voids and reduces the permeability.