JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008

JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008

METAL FORMING

(Production Engineering)

SET-II

1. (a) Derive an equation of yield shear stress for uniaxial tension. How it can be helpful to discuss about ’Yield criteria’ of metals.

(b) Explain Levy – Mises’ stress – strain relations?

 

2. (a) Describe ‘dislocation’ theory. How a Burger’s Vector is generally used in dislocation. How is displacement expressed by it ?

(b) Derive an expression for ‘Critical Resolved shear stress’.

 

3. (a) Explain the process of bending operation? Discuss various types of bending with neat sketches.

(b) How can spring back be offset? Explain the factors influencing spring back. What is its application and relative merits.

 

4. (a) What are the factors that influence selection of a press.

(b) Classify different presses for sheet working of metals. Discuss their principle and specific applications.

(c) What are the advantages of Mechanical press over Hydraulic Press.

 

5. (a) How do you analyse an extrusion process through a conical die. Determine total extrusion pressure.

(b) Derive an equation for power loss in extrusion.

 

6. (a) Sketch and describe the construction and working of hydrostatic extrusion and mention some of its applications and advantages.

(b) Discuss the effects of deformation speeds, lubricants and different die materials in hot and cold working processes.

 

7. (a) Differentiate between Drop forging and Press forging operations. What are the advantages of press forging over Drop forging.

(b) Enumerate the differences between Hot Forging, Cold Forging and Warm forging.

(c) Where forge welding is adopted ? How it can be classified ? Is it possible to forge Cast Iron specimen. Give your comments.

 

8. (a) Discuss various methods of applying lubricant during rolling process ? What are the characteristics of a lubricant used during rolling.

 (b) Discuss briefly about the type of defects generally found in Rolled products ?

Mention their probable causes and remedies.

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