Question

In a green sand moulding process, uniform ramming leads to _____

(a) uniform flow of molten into the mould cavity

(b) less chance of gas porosity

(c) less sane expansion type of casting defect

(d) greater dimensional stability of the casting

I have been asked this question in a job interview.

I need to ask this question from Green Sand Mould in section Pattern and Mould, Principles of Gating & Risering of Casting-Forming-Welding I

Answer 1

Correct answer is (d) greater dimensional stability of the casting

The explanation is: Uniform ramming of sand is very necessary for green sand moulding process. Uniform ramming of sand during mould preparation improves mould strength, and makes it dimensionally stable. Uniform ramming done to obtain a smooth and hard casting surface which prevents break out.