JNTU B.Tech II Semester Examinations, METAL FORMING, Aug/Sep 2008

JNTU B.Tech II Semester Examinations, METAL FORMING

, Aug/Sep 2008

(Production Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

SET-II

1. Write short notes on the following:

(a) Yield locus

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

 

2. (a) What is hot working? Is it possible to have hot working of metals at room

temperature? How? Explain with suitable examples.

(b) Assume that a tapered piece of copper has been stressed in tension beyond its

yield point and then annealed. Explain how the grain size will change along

the taper. [8+8]

 

3. Define hot working, warm working and cold working.Discuss the relative features

of hot work and cold work for Al, Pt and Molybdenum considering melting point,

brittleness and oxidation behaviour. [16]

 

4. Explain the following:

(a) Compound die

(b) Combination die

(c) Progressive die

(d) Transfer die. [4×4]

 

5. (a) What is Forging? Describe various types of forging dies.

(b) Sketch and describe counter flow forging hammer.

(c) Discuss the advantages and limitations of forging process. [7+4+5]

 

6. (a) Maximum draft in rolling is decided by coefficient of friction. Explain.

(b) Define Torue and power required for rolling. Describe how they can be esti-

mated.

(c) Calculate the rolling load if steel sheet is hot rolled 30 percent from a 40mm-

thick slab using a 900 mm-diameter roll. The slab is 760 mm wide. Assume

? = 0.30. The plane-strain flow stress is 140 Mpa at entrance and 200 Mpa

at the exit from the roll gap due to the increasing velocity. [5+6+5]

 

7. (a) Describe the common extrusion equipment and basic elements of an extrusion

die.

(b) Briefly explain the deformation and flow of metal during extrusion. [10+6]

 

8. Discuss the following: [8+8]

(a) Production of tubes and seamless pipes.

(b) Rod and wire drawing processes.

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