III-B.Tech. II Semester Supplementary Examinations December 2002/January 2003 MECHANICAL METALLURGY (Metallurgy & Material Technology) Max. Marks: 80
Answer any Five questions All questions carry equal marks --The following data for Zinc crystal were obtained
a) b)
90 -
P,
Kg
6.5 19.5 30.0 40.0 61.0 85.0
18.0 29.0 30.5 40.0 62.5 85.5
20.73 7.87 5.28 4.60 5.60 28.50
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1.
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Time: 3 Hours
Find the schmid factor if Area of cross section is 122 mm2. Find critical Resolved Shear Stress.
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2. a) Explain the need for multiplication of dislocations during plastic deformation. b) Describe the Frank-Read mechanism of dislocation multiplication.
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3. a) Why it is necessary to use different loads when making Brinell or Vicker’s hardness impression on two different materials? b) Brinell hardness impressions were made on samples of pure copper and a bronze using 2 mm ball indentor The results were: Pure copper – 20kg load – impression dia = 0.772 mm Bronze – 40 kg load – impression dia = 0.75 mm 4.
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a) b) c) d)
A metal sample of 10 mm dia was stressed in tension and the following informations obtained: A force of 30 KN gave a total elongation of 2 mm and a force of 34 KN gave a total extension of 11 mm over an original gauge length of 40 mm. Determine The value of the Co-efficient (K) and the exponent (n) The total extension at maximum load The maximum load applied The tensile strength of the material Contd….2.
Code No: 321802
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Set No:1
5. a) The weight of the pendulum of an impact tester is 20 kg and the length of the pendulum arm is 800 mm. If the arm is horizontal before striking the specimen. What is the striking velocity? b) Grey cast iron is not notch sensitive. Why?
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6. a) Calculate the theoretical cohesive strength of Iron if the young’s modules=210Gpa surface energy = 2.4 J/m2 and the lattice parameter of iron = 2.54oA. b) Differentiate between ductile and brittle fracture.
8.
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7. a) From the following data draw the stress cycle curve: mean = 200 MPa and R: - 0.33 b) How can you improve the fatigue property of an engineering material.
Explain the casting defects arising due to (a) Pattern making (b) pouring Discuss the causes and remedial action.
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Set. No.
2
Code No. 321802
III-B.Tech. II Semester Supplementary Examinations December 2002/January 2003 MECHANICAL METALLURGY (Metallurgy & Material Technology)
1.
Max. Marks: 80 Answer any Five questions All questions carry equal marks --What do you mean by the slip system in a crystal? Explain in brief.
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Time: 3 Hours
What is a dislocation? Explain with proper sketch the different type of dislocations in a crystal.
3.
Define hardness. Explain Brinell hardness measuring method with a neat sketch.
4.
A 5 cm diameter forging billet is upset from 12.5 cm to 5 cm. a) Determine the average axial strain and true strain in the direction of compression b) What is the final diameter of the forging billet.
5.
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2.
Explain the Charpy and Izod impact tests with neat sketches.
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6. a) Distinguish between ductile fracture and brittle fracture of engineering materials b) Describe the micro structural and environmental conditions that promotes brittle fracture. 7. a) How would you determine fatigue data in the laboratory? b) Fatigue occurs only when stress cycles between tensile and compressive states. Justify. Write short notes on casting defects, causes and remedial action arising due to (a) moulding practice and (b) melting
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Set. No.
3
Code No. 321802
III-B.Tech. II Semester Supplementary Examinations December 2002/January 2003 MECHANICAL METALLURGY (Metallurgy & Material Technology) Time: 3 Hours
2.
3.
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Answer any Five questions All questions carry equal marks --An isotropic material is subjected to uni axial tension. Show with a neat sketch the resolved stress on a plane inclined to the tension axis. Write an expression for the shear stress on this plane. Show that resolved shear stress has a maximum value when plane makes an angle of 45o with the tension axis.
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1.
Max. Marks: 80
Write short notes on (a) forces on dislocations and (b) forces between dislocations.
What are the precautions observed for getting a reproducible hardness value is Rockwell, Brinell and Vicker’s hardness testing.
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4. a) Draw engineering stress-strain diagram and true stress-strain diagram for mild steel. Discuss the differences between them. b) Why true strain is preferred for large changes in dimensions. 5.
Explain with a neat sketch the plane strain toughness testing.
6.
State Griffith fracture criterion. Derive an expression for the cohesive strength of a solid and compare its applicability with Griffith fracture stress for brittle solids.
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7. a) Explain the mechanism of fatigue failure of a material. b) What do you understand from the following properties and how are they obtained. (i) Proof stress (ii) Endurance limit Explain the casting defects arising due to melting and pattern making.
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Set. No.
4
Code No. 321802
III-B.Tech. II Semester Supplementary Examinations December 2002/January 2003 MECHANICAL METALLURGY (Metallurgy & Material Technology) Time: 3 Hours
Max. Marks: 80
Draw a schematic shear stress shear strain diagram of a single crystal of FCC. Identify various regions in it and explain their characteristic features.
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2.
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Answer any Five questions All questions carry equal marks --1. a) Derive an expression for the critical Resolved shear stress for slip based on schmid model and explain its significance. b) What is the effect of metal purity and temperature on this stresses?
3. a) Differentiate between Vicker’s and Brinell hardness test. b) Why Brinell is preferred for measuring hardness of cast alloys?
Determine engineering strains, True strain and reduction in area of the following situations a) extension from L to 1.1 L b) compression from h to 0.9h c) extension from L to 2L d) compression to zero thickness.
5.
Explain why the phenomena of Ductile to Brittle transition is observed only in BCC metals and not in FCC metals?
6.
Using Griffith equation for plane stress, determine the critical crack length for (a) Fe (b) Zn and (c) NaCl if the following constants apply. c, MPa , J/m2 E, GPa Fe 900 1.2 205 Zn 2 0.8 35 NaCl 2 0.15 50
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7. a) Draw a stress cycle whose R value is 0.5 b) What are the variables that affect the fatigue life? Explain. 8.
Write an essay about casting defects, causes and remedial actions arising due to (a) pouring and (b) moulding practice. @@@@@
b) Grey cast iron is not notch sensitive. Why? 6. a) Calculate the theoretical cohesive strength of Iron if the young's ... and the lattice parameter of iron = 2.54.
List out the practical considerations to be checked for continuous gas ... Explain how silica analysis is done in boiler water of power plant. 3. a) What is meant by ...
What do you understand by principles of planning a building? Prepare a typical · aspect diagram for the area where direction of prevailing breeze is from North-.
b) Draw the circuit diagram of 4-bit Johnson counter using D-flip flop and explain .... 6. a) Compare merits and demerits of ripple and synchronous counters.
Given: turbine diameter = 120m and turbine operating speed = 40 rpm at · maximum efficiency. Propeller type wind turbine is considered. 4. a) What is the basic ...
Obtain an expression for unit speed, unit discharge and unit power for a turbine. 2. a) What do you understand by air vessels? Explain with a neat sketch.
1.a) Obtain the expression for the resistance and capacitance for gas system. ... List various variables to be measured and controlled in nuclear power plant.
instructions at the beginning and end of this set of code in order to switch .... 5.a) Write an assembly language program that will examine an ASCII string of 100.
If the analog i/p voltage is +6.85 v, what will be the R-2R ladder · o/p voltage when ... b) Design a ramp generator using 555 timer having an output frequency of.
efficiency of the cycle and mean effective pressure for the cycle. ... b) Calculate the heat flux emitted due to thermal radiation from a black surface at · 6000.
8.a) Write a note on creep resistant materials. b) Explain all the ... b) Sketch the creep diagram, and explain the various stages of creep. @@@@@. Set No. 2.
What is the difference between radio compass and ADF? Explain the principle · and operation of Automatic direction finder. 6. Define analog and digital ...
endurance limit of a metal. b) What are the factors which affect the fatigue strength of materials? 7. a) What is creep? Draw an ideal creep curve and explain the ...
(i) Band Rate · (ii) Request Filter ... 3. a) Write the comparison between teleprinters and CRT terminals. b) What are the ... What savings does it offer? b) What is a ...
b) How does butadiene differ from isoprene? 4.a) Describe about the synthetic fiber industry in India. b) Write, with an example on each of the following.
graph. b) Draw the state space tree for m-closing graph using a suitable graph. 8. Present a program schema for a FIFO Branch & Bound search for a Least-Cost.
b) Explain the effect of Metallurgical variables on fatigue properties · 7.a) Explain Ductile to Brittle transition phenomenon. b) Compare charpy with Izod impact testing. 8.a) What is stress relaxation. Draw stress-strain curves for ductile and brit
Information Technology, Electronics and Control Engineering, Electronics and ... Computer Engineering, Computer Science and System Engineering) ..... Draw and explain the logic diagram of a master slave D flip-flop using Nand gates. ###.
Chemical Engineering, Mechatronics, Metallurgy & Material Technology, · Aeronautical ... b) What is cache memory? Where is it placed? What is its .... 7.a) Explain the steps involved in computing the coefficients of the regression · polynomial.
b) Classify the blast furnace stoves. What are the different values in the stove and · their functions? 3.a) What factors affect reducibility of iron ores? Discuss them.
1.a) Write the name of places for occurance of iron ores in India. b) Explain the process of either Sintering or Pelletizing. 2.a) Explain hearth, tuyeres, stack with ...
