Question

The formation of hot tears in the hand wheels or big gear wheels can be reduced by_____

(a) making the hub of greater strength

(b) reducing the thickness of the spokes

(c) increasing the ductility of the spokes

(d) increasing the thickness of the spokes

This question was posed to me by my college director while I was bunking the class.

Question is taken from Product Design for Sand Castings in section Pouring – Gating Design, Melting Furnaces, Melting and Casting Quality of Casting-Forming-Welding I

Answer 1

The correct answer is (c) increasing the ductility of the spokes

Best explanation: By increasing the ductility of the spokes, it is possible to reduce the formation of hot tears in the hand wheels or big gear wheels. The ductility can be increased by making the spokes curved and having them in odd numbers. The odd number of spokes ensures that the restraining force acts in only one direction making the wheel more ductile.