Name of the College : Sphoorthy Engineering College
University : JNTUH
Department : Metallurgy And Material Technology
Subject Code/Name : 09A51803/MECHANICAL METALLURGY
Year : December 2011
Degree : B.Tech
Year/Sem : III/I
Website : sphoorthyengg.com
Document Type : Model Question Paper
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/sphoorthyengg.com/4817-09A51803-MECHANICALMETALLURGY.pdf
Mechanical Metallurgy Question Paper
III B.Tech I Semester Examinations,December 2011
Time: 3 hours
Max Marks: 75
Related : Sphoorthy Engineering College 09A51804 Heat Treatment Technology B.Tech Question Paper : www.pdfquestion.in/4813.html
Answer any FIVE Questions :
All Questions carry equal marks :
1. (a) Sketch the transition temperature curves for a plain carbon steel tested in tension, torsion and notched impact.
(b) What is fracture toughness? Explain its importance. [7+8]
2. Construct and explain a three-dimensional plot showing the relationship between stress, strain and time, for T = Tm/2. [15]
3. The strain hardening of an annealed steel is expressed by where stress is in psi. A 25 mm diameter bar is drawn down to 20 mm and 15 mm in two steps using tapered cylindrical dies. Determine the plastic work per unit volume for each reduction. [15]
4. (a) Derive the Griffith’s equation.
(b) Explain the Griffith’s criterion used for smaller cracks. What is Griffith’s crack length? Explain. [7+8]
5. (a) What is plasticity? How the degree of plasticity is expressed? Explain.
(b) In what type of crystal structure do the more ductile metals exist? Why? Explain.
(c) Explain about stretcher strains. [5+6+4]
6. (a) What is a dynamic-hardness measurement? What is the working principle of the test?
(b) Name one hardness method which belongs to the indentation group. Explain its working. Discuss the advantages and limitations of the above method. [6+9]
7. (a) Classify the dierent kinds of crystal imperfections found in solids.
(b) Explain about vacancy defect.
(c) Explain what you mean by stoichiometric crystal defect.
(d) Explain about surface imperfections. [5+4+3+3]
8. (a) What factors are necessary for fatigue failure? Explain them.
(b) Draw the typical fatigue curves for ferrous materials and non-ferrous materials. Explain them. [7+8]
Code No: 09A51803
R09 Set No. 4
1. (a) Determine the miller indices of slip directions on the (101) plane in BCC unit cell.
(b) Why does a dislocation of larger Burger’s vector try to break itself into smaller dislocation? Discuss. [7+8]
2. (a) The critical impact velocity for steel is 160 ft/s, and the longitudinal sound velocity is 19,500 ft/s. If E = 30 x 106 psi and the density is 0.32 lb/in3, what is the fracture stress under these impulsive-loading conditions?
(b) What is CTOD test? Explain its importance. [7+8]
3. Explain the following:
(a) Upper yield point
(b) Modulus of toughness
(c) Stiness
(d) Modulus of resilience. [15]
4. Write short notes on the following:
(a) Size eect on fatigue
(b) Surface eects on fatigue. [15]
5. (a) Distinguish between
i. crack resistance
ii. energy release rate.
Discuss about the two in studying the possibility of crack becoming critical. (b) Discuss dierent types of fractures in brittle materials. [8+7]
6. (a) Explain the purpose of the swivel head commonly used in compression tests. Make a sketch showing the proper arrangement of such a head.
(b) Explain the possible errors that may arise during compression test. [7+8]
7. Steady-state creep rate can be expressed by “_s = Bane??Q=kT . Apply this relation-ship to the creep of a steel support rod in a boiler operating at 10000F. The rod is stressed in tension to 8,000 psi and its creep elongation must not exceed 10 percent.
Using the data given in gure 1, evaluate the constants in the creep equation and estimate the lifetime of the rod. [15]
III B.Tech I Semester Examinations,December 2011 Set III :
1. (a) Develop an expression for the true stress at necking in terms of the material tensile strength and strain hardening coecient.
(b) Write down the general form of equation of stress-strain curve.
(c) Explain about flow curve. Give reasons why it is called so. [7+4+4]
2. Peterson has shown that for an average value of Kt = 2 the notch sensitivity index is given by q = 1/(1+a/r), where `a’ is a \particle size” dependent on the material and r is the notch radius. Kun and Hardrath have related with the tensile strength of the steel. Using these data, plot a curve of q versus r for steels of dierent strengths. [15]
3. Explain notched-bar impact tests with neat sketches. Explain their advantages and limitations. [15]
4. (a) In Brinell method, would you use same load both for hard and soft materials? Explain. On what factors the load depends? Explain.
(b) Why tungsten carbide ball indenter is used for testing of hard metals?
(c) Describe the surface preparation for Brinell hardness test. [7+4+4]
5. (a) What are the possible errors which may arise in compression test? Explain.
(b) Draw stress-strain diagram for gray cast iron in compression test and compare all corresponding points in tension test. [7+8]