JNTU
JNTU B.Tech II METALLURGY AND MATERIALS ENGINEERING Previous Question Paper (November/December - 2018 - R15)
Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Define the terms: Ledeburite, Cementite, ferrite.
Answer
Ledeburite is the eutectic mixture of austenite and cementite found in iron-carbon alloys containing 4.3% carbon. Cementite (Fe3C) is an intermetallic compound of iron and carbon that is extremely hard and brittle. Ferrite (α-iron) is a solid solution of carbon in body-centered cubic iron, characterized by high ductility and softness.
What are the applications of Alloy cast Iron?
Answer
Alloy cast irons are used in applications requiring enhanced mechanical properties, corrosion resistance, or heat resistance. Key applications include engine cylinder blocks, piston rings, brake drums, chemical processing equipment, and furnace parts where standard grey or white cast iron would fail due to wear or thermal stress.
What information do you get from equilibrium diagrams?
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What do you mean by miscibility gaps?
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What is cryogenic treatment?
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What is hardening?
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Define diffusion coefficient.
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Define Gaussian error function.
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What is meant by functionality of a monomer?
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What is abbrasive-ceramic? Give an example.
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Part B
What is white cast iron? Explain about composition, microstructure, properties and applications of white cast Iron.
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What is CEV? Explain its importance.
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How austempering is achieved in S. G. iron castings?
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What are the possible applications of austempered S. G. iron?
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Discuss the relationship between properties of the alloys and equilibrium diagrams.
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Discuss Fe-Fe3C phase diagram and discuss different phase transformation reactions.
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Draw TTT diagram for eutectoid steel and discuss the phase transformations observed when cooled at different rates.
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Describe the Jominey end quench test with a neat sketch adopted for determination of hardenability of steel.
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What are the commonly used case hardening methods? Explain the principles of any three case hardening methods.
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Explain in detail the Fick’s law of diffusion.
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Explain the differences between crystallization of polymers and other solids.
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What factors affect the crystallization of polymers?
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“Thermoplastic polymers can be recycled but thermosetting polymers cannot be recycled”. Why?
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Why crystallized polymers are more denser and stronger than amorphous polymers?
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Why plasticizers and fillers are added to the polymers?
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