Question

The primary purpose of sprue in casting mould is to _____

(a) act as a reservoir for molten metal

(b) feed the casting at rate consistent with the rate of solidification

(c) feed molten metal from the pouring basin to the gate

(d) help feed the casting until all solidification takes place

The question was posed to me during an interview.

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

Answer 1

The correct option is (c) feed molten metal from the pouring basin to the gate

The explanation: Sprue is a connecting passage between pouring basin and runner for molten metal in the tapered form to avoid the aspiration effect so that pressure equally maintained in the column of liquid metal streaming to the mould.