Question

The heat transfer through the interface of metal and mould is always considered as of convection mode.

(a) True

(b) False

I had been asked this question during a job interview.

My question is from Solidification with Predominant Interface Resistance topic in section Cooling and Solidification of Casting-Forming-Welding I

Answer 1

Correct answer is (b) False

For explanation I would say: When the air gap forms at the interface, the heat transfer across the interface drops rapidly. The mode of heat transfer through the gap is considered to be due to both conduction and radiation, conduction is more dominant mode at the lower temperatures while radiation depends upon the surface temperatures and emissivities.