Thapar University 2006 B.E Mechanical Engineering Industrial Metullargy - exam paper
Thapar Institute of Engineering & Technology
B.Tech Mechanical Engineering (3rd Year)
Final Term exam
ME038 (Industrial Metullargy & Materials)
THAPAR INSTITUTE OF ENGINEERING AND TECHNOLOGY MECHANICAL ENGINEERING DEPARTMENT B.E Illrd YEAR (MECHANICAL)
ME-039 INDUSTRIAL METALLURGY AND MATERIALS MARKS: 60 TIME: 3 Hrs
Note: Attempt five questions in all. Qfr. is compulsory. All questions carry equal marks.
Answers should be brief & to the point. Attempt all parts of a question at one place.
Draw neat and labeled diagrams wherever required.
Evaluated answer sheets can be seen in the office of teacher incharge on 16.12.06 between 10.00-ll.a.m.
QL
a) What is the basic difference in the case hardening treatment given to low carbon steels and that given to medium carbon steels. Why does such a difference exist?
b) What are the three basic reasons for carrying out carburizing and other related processes only at high temperatures? What are the drawbacks of making such temperatures exceptionally high?
c) What is temper embrittlement? Explain the conditions under which it occurs and the various measures to eliminate it?
d) State the Harris equation? State its significance. For which steels is this equation applicable? t
(3X4)
Q2.
a) Surface heat treatments come into picture where conventional treatments cant be used. Discuss.
b) Explain the role of activators with an example in case of pack carburizing?
c) Discuss the steps involved in isothermal annealing.
d) What is fourth stage tempering? What type of microstructure and
characteristics are obtained in the steel after receiving this treatment?
(3X4)
Q3.
a) Discuss what is a CCT diagram? Draw this labeled diagram for eutectoid steel. Bring out the main points of difference between a CCT diagram and the corresponding TTT diagram for the eutectoid steel?
b) What is Widmanstattan structure? Under what conditions does it get formed? What type of heat treatment can be given to eliminate it?
c) What are the benefits derived by normalizing hypereutectoid steel rather than full annealihg it? Under what conditions normalizing can not eliminate full annealing?
d) Describe with an example the difference between hardness and hardenability.
(3X4)
a) What is the reason behind the high hardness of martensite? On what factors does the Ms temperature depend? Which alloying elements can increase this temperature?
b) For a eutectoid steel, below the lower critical temperature, as the transformation temperature is decreased, the incubation period first decreases up to the knee and then starts increasing. Why?
c) Draw a heat labeled Iron-Iron Carbide diagram? Mark all the critical temperature lines and also the invariant reaction points on it? Is this diagram a true equilibrium diagram? Explain.
d) Why steels are generally rolled and forged between 800-1000C temperature range? (3X4)
a) Slate and explain the Gibbs rule? What is the significance of this phase rule?
b) How do the phases affect the properties of a metallic system? Explain with an example.
c) What is meant by the term alloy? With the help of a line diagram, show the metallurgical classification of binary alloys.
d) What are the factors on which coring depends? What are the consequences of this defect when present in steel?
(3X4)
a) What is meant by the term components of a system? Explain with examples.
b) What are type II systems? Why are these called eutectic systems? With the help of thermal analysis technique, obtain the Pb-Sn equilibrium diagram.
c) What are the main points of difference between inherently fine and inherently coarse grained steels?
d) What do the A0,A2 and ACfn lines signify?
(3X4)
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