JNTU B.Tech II Semester Examinations, METAL FORMING
, Aug/Sep 2008
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. (a) Explain why plastic deformation arrests the fracure of a part.
(b) Distigunish between the terms total elongation and uniform elongation.
(c) Explain about the ‘NECKING’ phenomena. [5+4+7]
2. (a) Why is it necessary to have a lubricating system in plastic deformation proceses and what are the various lubricating systems used in metal forming units.
(b) Explain the various property and structural changes that take place when a
cold worked metal is heated continuously. [8+8]
3. (a) What is the alloy which has highest observed elongation as a superplastic
material. Explain in detail.
(b) What are the two kind of superplasticity. Explain them in detail.
(c) At what strain rates and temperatures, superplastic deformation takes place.
4. (a) How does sheet metal forming difffer from roling, forging and extrusion? Ex-
plain in detail.
(b) Explain the differences between punching and blannking [8+8]
5. (a) Elaborate on
i. presses and
ii. hammers used in forging.
(b) Define clearly the Flash and draft in forging and mention their significance at
(c) Draw neat diagrams of forging equipment and indicate their characteristics
6. Write short explanatory notes on the following: [3+3+4+6]
(a) Roll of friction in rolling
(b) Three-high mill
(c) Horse power in rolling
(d) Theories of cold rolling.
7. (a) Explain how extrusion speed and temperature can be selected for hot extrusion.
(b) Explain residual stresses in tubes.
(c) Explain about Impact extrusion process. [6+5+5]
8. Discuss the following: [8+8]
(a) Production of tubes and seamless pipes.
(b) Rod and wire drawing processes.