JNTU Question Papers Examinations Mechanical Working Of Metals 2nd Sem Apr May 2008

JNTU Question Papers

Examinations Mechanical Working Of Metals 2nd Sem Apr May 2008

1. (a) Explain in detail about ‘stress at a point’.

(b) Explain the following terms:

i. Continuum mechanics

ii. constitutive equations.

(c) How many components are required to completely describe the state of a stress? What are these? Explain with example. [5+6+5]

 

2. (a) Discuss Vonmises yield criteria for plastic deformation.

(b) Write short notes on the following:

i. Yield locus

ii. Levy-Mises equations(Flow rules). [8+8]

 

3. (a) Explain the importance of ‘incubation period’ during the anneal of cold worked materials.

(b) Draw a schematic sketch which represents/explains, recrystallization process and explain. [6+10]

 

4. (a) Describe the difficulties in defining the term ‘forgeability’

(b) A 60mm thick, 30mm wide and 600 mm long mild steel specimen is to be forged with flat dies to a final thickness of 30mm, keeping length constant. Determine the forging load required for operation

i. under sliding friction condition with coefficient of friction as 0.06

ii. under sticking friction condition at 90oC with coefficient of friction as 0.7. [4+12]

 

5. (a) Sketch the mill stand arrangement in a universal mill and explain its operation.

(b) What is the relation between the arc of contact and roll pressure? Explain. [8+8]

 

6. (a) Explain the importance and criticality in the selection of rolling variables.

(b) Explain defects and their remedies in rolled products. [8+8]

 

7. (a) What is extrusion? How is it different from drawing?

(b) Differentiate between hot and cold extrusion processes with respect to operational details and applications? [6+10]

 

 

8. Write short notes:

(a) The effect of die angle on the components of the total energy of deformation in wire drawing.

(b) Limit of drawability for a steady-state wire drawing. [8+8]

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