JNTU IV B.Tech I Semester Supplimentary Examinations, February 2008
(Metallurgy & Material Technology)
1. (a) How is L.D. process name come into existence? Discuss some of important characteristics of L.D. process?
(b) Draw a neat – sketch of water-cooled lance showing O2-gas passage, water inlet and outlet.
(c) What is the disadvantage of using a lance with a cylindrical – nozzle in L.D. process.
2. (a) What is Steel? Classify steels on the basis of chemical composition?
(b) List any two probable ancient methods of steel making and explain any one of them.
(c) What do you mean by ’semis’ of steel plant products?
3. (a) What are the advantages of a thin-slag?
(b) When is slag said to be dry? Give an example of steel making process where a dry slag is obtained? Explain the process of dry-slag formation?
4. (a) What is the most effective- dephosphoriser line, magnesium, manganese oxide, iron oxide. Arrange them in decreasing order of their dephosphorisation ability.
(b) How does iron-oxide increase the dephosphorisation index? Why is there a maximum dephosphorisation index at around 15% FeO?
5. (a) How can you assess the Silica-content and ironoxide-content of slag in acid open hearth process?
(b) How can you say that metal is ready for tapping in acid open hearth process.
6. Explain the different parts of furnace body of basic electric arc furnace?
7. Explain the how the ladle-desulphurisation is carried out in secondary steel making?
8. Write a short notes on steel production in India.