Code.No: 36056

R05

SET-1

.in

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD III .B.TECH –II SEM SUPPLEMENTARY EXAMINATIONS JANUARY- 2010 MECHANICAL WORKING OF METALS (METALLURGY & MATERIAL TECHNOLOGY) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks --What is Mohr’s circle? What is the significance of Mohr’s circle? Draw the Mohr’s circle (Three dimension) for Uni-axial compression, Bi-axial tension, Triaxial tension, Uni-axial tension plus bi-axial compression. [16]

2.a)

Describe the following terms in detail: i) Flow curve ii) Bauschinger effect Derive the expression for the true stress and true strain in terms of engineering stress and engineering strain. [8+8]

b)

or ld

1.

Give the classification of metal forming processes and discuss them in detail. Distinguish between cold working and hot working of metals. [8+8]

4.a) b)

What are the various basic forging operations? Explain. Derive an equation for forging pressure in plane strain with Coulomb’s law of sliding friction. [8+8]

5.

Explain the different types of rolling classified based on arrangement of rolls, principle of operation with the help of neat sketches. [16]

6.a) b)

Describe the role of back tension in rolling. What is rolling torque? How it is measured?

7.a) b)

Differentiate between hot extrusion and cold extrusion processes. Describe the different types of metal flow patterns observed in extrusion process with neat sketches. [8+8]

nt

uW

3.a) b)

Differentiate between tube sinking and tube drawing. Explain the wire drawing operation with a neat sketch.

Aj

8.a) b)

--ooOoo--

[8+8]

[8+8]

Code.No: 36056

R05

SET-2

.in

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD III .B.TECH –II SEM SUPPLEMENTARY EXAMINATIONS JANUARY- 2010 MECHANICAL WORKING OF METALS (METALLURGY & MATERIAL TECHNOLOGY) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks --Explain the state of stress in three dimension. Describe with suitable examples why two subscripts are needed to describe a shear stress. [8+8]

2.a)

Draw the engineering stress-strain diagram for pure aluminum and explain the various salient points in it. Describe about octahedral shear stresses and octahedral shear strains. [8+8]

b)

or ld

1.a) b)

The cold worked components are generally subjected to annealing process. Why? Describe the annealing process in detail with a neat sketch. [16]

4.a) b)

Distinguish between open die forging and closed die forging. Describe in detail powder metallurgy forging.

5.a) b) c)

What are the property requirements of material for a rolling mill roll. Draw the mill stand arrangement in a universal mill and describe its operation. Describe the relation between the arc of contact and roll pressure. [5+6+5]

6.

Discuss in detail rolling defects and their remedies with the help of neat sketches. [16]

7.a) b)

Differentiate between direct extrusion and indirect extrusion processes. What are the principle variables that influence the force required to cause extrusion? Explain. [8+8]

8.a) b)

Explain the types of residual stresses in rod, tube and wire drawing operations. Describe the stress analysis of tube drawing. [8+8]

Aj

nt

uW

3.

--ooOoo--

[8+8]

Code.No: 36056

R05

SET-3

.in

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD III .B.TECH –II SEM SUPPLEMENTARY EXAMINATIONS JANUARY- 2010 MECHANICAL WORKING OF METALS (METALLURGY & MATERIAL TECHNOLOGY) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks ---

Describe the construction of Mohr’s circle in two dimensional state of stress. Consider an elemental cube whose faces represent the principle planes. Draw maximum shear stress plane for the cube. Justify in detail. [8+8]

2.a) b)

What are the advantages of true strain over engineering strain? Write the mathematical expression for Von Mises’ yield criterion and explain in detail. [8+8]

3.a) b)

What are the factors which effect re_crystallization temperature? Explain. Describe the effect of strain rate on deformation processing. [8+8]

4.

Write short notes on: a) Forging defects b) Forging hammers.

or ld

1.a) b)

[16]

Describe the significance of angle of bite and coefficient of friction in rolling. Differentiate between hot rolling and cold rolling. [8+8]

6.

Describe the theories of cold rolling and hot rolling in detail.

7.

Describe the equipment used in extrusion process in detail with neat sketches. [16] What are the various methods of tube drawing? Explain with neat sketches. Describe the stress analysis of wire drawing. [8+8]

Aj

nt

8.a) b)

uW

5.a) b)

--ooOoo--

[16]

Code.No: 36056

R05

SET-4

2.a) b) c)

Describe in detail the following: a) State of stress at a point b) State of strain at a point.

[16]

What are the advantages and limitations of Tresca criterion over Mises yield criterion? Describe the Tresca criterion in detail. Differentiate between elastic deformation and plastic deformation. [6+5+5]

or ld

1.

.in

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD III .B.TECH –II SEM SUPPLEMENTARY EXAMINATIONS JANUARY- 2010 MECHANICAL WORKING OF METALS (METALLURGY & MATERIAL TECHNOLOGY) Time: 3hours Max.Marks:80 Answer any FIVE questions All questions carry equal marks ---

Derive the equation for an amount of work done in plastic deformation using the following methods: a) Slab method b) Uniform-deformation energy method. [16]

4.

Explain various forging equipment and mention their relative advantages and limitations with the help of neat sketches. [16]

5.a)

Describe the effect of strip tension on the distribution of roll pressure distribution with the help of a neat sketch. Describe the distribution of roll pressure along the arc of contact with a neat sketch. [8+8]

b)

List three basic requirements for a good rolling lubricant. A 300 mm wide aluminum alloy strip is hot-rolled in thickness from 20mm to 15mm. The rolls are 1 m diameter and operate at 100 rpm. The uni-axial flow stress for the aluminum alloy can be expressed as σ = 140ε 0.2 MPa. Determine the rolling load and the power required for this hot reduction. [8+8]

nt

6.a) b)

uW

3.

Write short notes on: a) Extrusion defects b) Production of seamless pipe and tubing.

Aj

7.

8.

Write short notes on: a) Patenting b) Defects in rod and wire drawing c) Wire drawing die. --ooOoo--

[16]

[16]