Question

Which of the following ways can use for stopping the rapid solidification of the molten metal in the mould?

(a) By having the mould of high permeability

(b) By making a uniform flow of molten metal

(c) By creating high pressure on the molten metal

(d) By using too much superheat

This question was addressed to me in class test.

The above asked question is from Effects of Friction and Velocity Distribution topic in section Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

Answer 1

The correct option is (d) By using too much superheat

The explanation: When the liquid metal is poured very slowly, then the time taken to fill up the mould is rather long and the solidification may start even before the mould has been completely filled up. This can be avoided by using too much superheat, but this creates the gas solubility problem which is not good for castings.