JNTU III B.Tech Supplimentary Examinations, Aug/Sep 2008
FOUNDRY AND WELDING
1. (a) Explain the various steps involved in making a casting.
(b) Explain why is that a Pattern is made in two or more pieces. Explain with typical examples.
2. (a) Is it, Possible to obtain a sound casting of a solid bar by centrifugal casting Process? Give reasons in support of your answer.
(b) Explain why most die castings not made out of high strength materials?
(c) ‘Large parts can’t be manufactured by the Centrifuging process’. Comment on the statement.
3. (a) Explain about dendritic freezing and freezing of metals and alloys.
(b) How would you find an expression for the critical radius of the Nucleus. Explain the effect of under cooling on the critical radius.
4. (a) Explain the factors to be considered in selection of weld joint.
(b) Explain various welding positions.
(c) Explain various types of welds with neat sketches.
5. (a) State and explain the factors that may influence metal transfer phenomena when using a metal arc welding process.
(b) Explain the reasons why damp flux coated electrode should not be used for welding mild steel.
6. (a) Explain the reasons for estimating welding costs.
(b) Discuss the factors involved in welding costs.
7. (a) With a neat sketch explain the compression moulding process of plastics.
(b) Explain the various advantages and disadvantages of plastics.
8. (a) Explain how particle size affects the properties of products of powder metal- lurgy?
(b) What are the characteristics of electrolytic powders?
(c) Discuss the manufacture and application of sintered carbides.