Question

The _______ is responsible for the impact strength in the molding sand.

(a) Aggregates

(b) Refractoriness

(c) Impurities

(d) Permeability

The question was asked in a job interview.

My doubt stems from Properties of Moulding Sand topic in section Pattern Materials & Moulding Sand Tests of Foundry and Forging

Answer 1

Right answer is (a) Aggregates

For explanation: In a foundry, the molding sand forms an important part of the cope and drag. It should have high impact strength, stability and permeability and this is imparted by silica sand in the form of granular quarts which has enough refractoriness to cast all of these strengths to the molding sand.