What are the bonding theories?
A. Electrostatic bonding theory
B. Surface tension theory
C. Block and wedge theory
D. All of these
Answer: Option D
This Question Belongs to Metallurgical Engineering >> Foundry Metallurgy
Why the quality of sand deteriorates if the same molding sand is used again and again?
A. Build up of clay and other organic coatings on the molding sand particles
B. Presence of foreign and scrap matter like iron particles, feyalite, etc.
C. Occurrence of pieces of oil sand
D. All of these
Shrinkage allowances is also known as
A. finish allowance
B. contraction allowance
C. taper allowance
D. camber allowance
A. 70% sand and 30% clay
B. 40% sand and 60% clay
C. 30% sand and 70% clay
D. 60% sand and 40% clay
The low permeability in sand can cause which of the following defects in casting
A. Rough surface
B. Blow holes
C. hot tears
D. Drop
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