JNTU
JNTU B.Tech III FOUNDRY TECHNOLOGY Previous Question Paper (December - 2018 - R15)
Note: This question paper contains two parts A and B. Part A is compulsory. Part B consists of 5 Units. Answer any one full question from each unit.
Part A
Give the chemical composition of the moulding sands.
Answer
Moulding sand primarily consists of silica grains (SiO2) ranging from 75% to 95%, clay (usually bentonite or kaolinite) acting as a binder (5% to 15%), moisture (2% to 8%), and minor additives like coal dust, wood flour, or dextrin to improve specific properties.
Give the limitations of using wood as a pattern material.
Answer
The limitations of wood as a pattern material include: 1) It is prone to moisture absorption, leading to warping and dimensional instability; 2) It has low resistance to wear and abrasion, making it unsuitable for high-volume production; 3) It is susceptible to attacks by insects and rot over time.
Write the chemical reaction taking place in the CO2 process.
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What are the causes of mismatch?
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What are the parameters to be considered to get a good casting by centrifugal casting process?
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What are the advantages of squeeze casting?
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Draw the cooling curves for pure metals and alloys.
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What is meant by degassing in melting process?
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Write the cold setting agents used in cold setting process.
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What is the purpose of chaplets?
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Part B - Unit I
Explain the different pattern allowances.
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Explain any five properties of a moulding sand.
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Explain the different sands used in foundry.
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Draw and explain neatly any one five types of patterns.
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Part B - Unit II
Explain with the help of neat diagram the shell moulding process.
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Explain any one testing method to identify the casting defects.
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Explain the different elements present in a gating system.
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Draw and explain any five defects occur in a casting.
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Part B - Unit III
Explain in detail the low-pressure die casting process.
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Explain briefly the semi-centrifugal process.
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Explain step by step the investment casting process.
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Differentiate between cold chamber and hot chamber die casting.
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Part B - Unit IV
Explain about the directional solidifications.
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Draw the microstructure of a casting. Explain its features.
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Explain the different stages in a cupola furnace.
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Explain and derive the critical nucleus radii in a homogeneous nucleation.
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Part B - Unit V
Write short notes on Furon-No-Bake process.
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Write short notes on types of cores.
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Write short note on continuous casting.
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Write short note on self setting process.
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