Question

Improper risering has always resulted in the formation of voids inside the castings.

(a) True

(b) False

I got this question in my homework.

My doubt is from Riser Design in section Pattern and Mould, Principles of Gating & Risering of Casting-Forming-Welding I

Answer 1

The correct choice is (a) True

Best explanation: The main reason for the formation of voids inside the castings is that the liquid metal in the centre which solidifies in the end is not fed during the solidification of the castings; hence the liquid shrinkage ends up as a void. This can be avoided by proper design of the riser in the casting system.