Question

Which of the following compositions of the shell sand is used for avoiding of thermal crack during pouring?

(a) Silica sand

(b) Zircon sand

(c) Resin

(d) Additives

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This is a very interesting question from Shell Moulding topic in division Special Casting Techniques of Casting-Forming-Welding I

Answer 1

The correct answer is (d) Additives

To explain: Generally, additives are added to the sand mixture to improve the surface finish and also for the avoiding of any thermal crack during pouring. Some of the additives used are coal dust, manganese dioxide, calcium carbonate, pulverized slag and ammonium boroflouride.