Question

Due to mould oscillation to minimize friction, oscillation marks formed on the surface of casting does not affect the castings.

(a) True

(b) False

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

The origin of the question is Solidification with Predominant Resistance in Mould in division Cooling and Solidification of Casting-Forming-Welding I

Answer 1

The correct answer is (b) False

For explanation I would say: The oscillation marks itself is a surface defect and its severity may prevent hot rolling. And increased thermal resistance at the bottom of mark reduces the local cooling rate which retards shell growth and coarsens the local microstructure, this can disturb the whole casting by inducing defects in the casting.