JNTU B.Tech Examinations, FOUNDRY AND WELDING, Aug/Sep 2008
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. (a) Explain how rapid prototyping methods are cutting lead times of proving the
new casting designs?
(b) Explain how rapid prototyping methods can build master patterns very rapidly?
2. (a) Discuss the suitability of zircon, quartz, olivine, alumino-silicate, and chromite
sands in a ferrous industry based on their properties.
(b) What the role of following additives to sand mixes: Carbonaceous additions,
cellulose, and cereals? [10+6]
3. (a) What are the problems associated with feeding a vertical centrifugal casting
machine? How the molds are fed from the ladle in practice?
(b) Explain the causes of the following casting defects in centrifugally cast parts:
raining, and banded segregation. [10+6]
4. (a) What is the function of sprue well? How do you eliminate the possibility of sand abrasion at the bottom of sprue well?
(b) Sketch a drag runner and cope ingates in a gating system.
(c) What are the disadvantages of bottom gating? [6+6+4]
5. (a) How does straight polarity differ from reverse polarity. Explain them in detail.
(b) What are the principle sources of current supply for arc welding process. With
the help of neat sketches and circuit diagram, explain their working procedure.
(c) What is meant by penetration? Explain its relevance in welding process.
6. (a) Compare brazing and braze welding. What are their specific applications?
(b) What are the different costs considered in various welding processes? Explain
them in detail. [8+8]
7. (a) Describe the advantages of cold forming of plastics over other processing methods.
(b) Describe the methods used to make tubular plastic products. [7+9]
8. (a) Discuss the important properties and various testing methods of metal powders.
(b) Describe isostatic and continuous compaction techniques. [8+8]