Question

A casting of cubical shaped structure is required with 60 mm side. Assume volume shrinkage of casting as 2.3%. If the height of the side riser is 30 mm and riser volume desired is 4 times the shrinkage in casting, then appropriate riser diameter (in mm) is

• A. 29
• B. 20
• C. 15
• D. 120

Answer 1

The correct option is D 120

$V_C={60}^{3}m{m}^3$

$V_{SC}=\frac{2.3}{100}\times V_C=4968m{m}^3$

$\text{Riser height = 30 mm}$

$V_r=4V_{Sc}$

$\frac{\pi }{4}{D}^{2}H=4\times 4968$

$\Rightarrow D=29.04mm$

$\text{According to sufficient condition}{\tau }_r\ge {\tau }_C\text{(should be)}$

$\text{But in this case}{M}_r<M_C$

$\therefore \text{Equating}{M}_r=M_c$

$\text{Hence,}{D}_r=120mm$