JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008
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) Differentiate between Point Defects and Surface Defects. Describe with different sketches.
(b) Differentiate between Ideal crystals and perfect crystals ? How the strength of perfect crystals can be estimated ?
3. (a) Discuss in detail about the process parameters and estimation of loads in Deep Drawing.
(b) Discuss the following briefly with sketches.
i. Trimming dies and Bending dies
ii. Punching, and Fine Blanking.
4. (a) Sketch and explain the working of progressive die. Indicate various elements on it.
(b) Sketch a single die used in sheet metal working. How do you select clearances between punch and die. Explain in detail.
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) In a wire drawing operation, determine the drawing stress and total drawing load using following data:
Initial wire diameter = 6 mm
Final wire diameter = 3.2 mm
Die angle = 180
Die land = 4mm
Coefficient of friction = 0.15
Yield stress = 26Kg/mm2.
(b) Indicate the composition of Extrusion die materials. Describe the causes of defects that occur in Wire Drawing.
7. (a) Describe the process of Press Forging with a neat Sketch. Enumerate the merits and demerits of Forging.
(b) List out different forging operations. Discuss in detail.
8. (a) List out the different structural shapes formed by Rolling with sketches. Sketch a Cluster Mill and indicate elements in it.
(b) Describe the principles of Ring Rolling and its applications. Mention its relative merits and limitations.