Question

Which of the following can be the reason for the aspiration effect?

(a) High pressure of molten metal

(b) High pouring temperature of molten metal

(c) Low viscosity of molten metal

(d) High viscosity of molten metal

The question was asked during an interview.

My question is taken from Aspiration Effect in portion Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

Answer 1

Right choice is (b) High pouring temperature of molten metal

Explanation: High pouring temperature which increases the amount of gas absorbed (leads to aspiration effect) by the molten metal in the furnace, in the ladle and during the flow in the mould. When gases not allowed to escape, would be trapped inside the casting and weaken it.