Project ForgeA cast product of a particular material has dimensions 75 mm × 125 mm × 20 mm. The total solidification time for the cast product is found to be 2.0 minutes as calculated using Chvorinov's rule having the index, n=2. If under the identical casting conditions, the cast product shape is changed to a cylinder having diameter=50 mm and height=50 mm, the total solidification time will be ___ minutes (round off to two decimal places).
Explanation
Box: V=75×125×20=187500mm³, A=2(75×125+75×20+125×20)=26750mm², V/A≈7.0093mm. C=2.0/(7.0093)²≈0.040707. Cylinder (D=H=50mm): V=π(25)²×50≈98174.8mm³, A=2π(25)²+2π(25)(50)≈11781.0mm², V/A≈8.3333mm. t = 0.040707×(8.3333)² ≈ 2.83 min.
Source: GATE ME 2021 Session 2 (ME-2) (2021)
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