Material Technology - May 2013

Mechanical Engineering (Semester 4)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Discuss the full Annealing heat treatment of steel.(6 marks) 1 (b) Draw neat iron iron-carbide equilibrium diagram indicating all important temperature, phases and composition. Explain the slow cooling of an alloy containing 0.3% C steel, when cooled from 1600°C to room temperature. Draw micro-structure at each phase and calculate phases in the alloy at various points by lever rule from liquid state to room temperature.(14 marks) 2 (a) What are Line defects in crystals? Explain the various Line defects in detail.(10 marks) 2 (b) Define the term 'Hardenability' . Discuss the factor affecting hardenability and explain any one of the hardenability tests.(10 marks) 3 (a) State and explain Slip mechanism of plastic deformation. What is Slip system? Explain Slip system in various lattice structures such as FCC, HCP and BCC.(10 marks) 3 (b) What is Diffusion Coating? Name its different methods. Discuss any one process of diffusion coating in detail on basis of principle, process, advantage and applications.(10 marks) 4 (a) Define Fracture and give a brief classification of fracture. State Griffith's theory of brittle fracture and derive Griffith's equation.(10 marks) 4 (b) What is Carburizing? Explain the heat treatment after Carburizing.(10 marks) 5 (a) Define Fatigue failure. Give examples of components prone to fatigue failure. Discuss fatigue testing and explain SN curve for ferrous and non-ferrous metals.(10 marks) 5 (b) Explain the various transformation in Iron-Iron Carbide Equilibrium diagram.(10 marks) 6 (a) Define Creep. Explain the mechanism of creep failure.(10 marks) 6 (b) Explain in detail the Heat Treatment for 18-4-1 Tool Steel.(10 marks)

Write Short Notes on any four:-

7 (a) Recrystallization and effect of recrystallization temperature.(5 marks) 7 (b) Maraging heat treatment process.(5 marks) 7 (c) Precipitation Hardening.(5 marks) 7 (d) Difference between Annealing and Normalizing.(5 marks) 7 (e) Effects of alloying elements on Ferrite.(5 marks) 7 (f) Hume Rothery's rules of solid solubility.(5 marks)