Question

The magnitude of the air gap at the interface of casting and mould continuously decreases with time.

(a) True

(b) False

This question was addressed to me in an internship interview.

This is a very interesting question from Solidification with Predominant Interface Resistance topic in portion Cooling and Solidification of Casting-Forming-Welding I

Answer 1

Right option is (b) False

For explanation: The constant air gap width at the interface cannot be assumed for simulation. The magnitude of the air gap continuously increases with time. The time of start of the air gap at the corner of the casting is always less than that for the middle, and the air gap never starts simultaneously at all points in the casting.