Rr321803-foundry-technology

Set No. 1

Code No: RR321803

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FOUNDRY TECHNOLOGY (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Write an essay on suggesting steps to be taken to improve the performance of metal casting industry (Foundry) in India. [16] 2. How is grain fineness of base sand for use in molding specified? Mention the procedure to test fineness and its effect on the following. [4X4=16] (a) green strength. (b) Permeability. (c) Collapsibility. (d) Surface finish. 3. (a) List in descending order of importance the various metals and alloys that are employed for making die castings, with suitable explanation. [8+8] (b) Explain under what production conditions does plaster mold casting seem to be justified. 4. (a) What do you mean by centre line feeding resistance. Explain its importance in solidification of castings [8+8]. (b) Explain the importance of cores. 5. What process parameters are to be considered in controlling the grain size of castings. What is the effect of grain size on the properties of castings? [16] 6. Discuss critically the Aluminum and aluminium alloys foundry practice in the back grand of [4X4=16] (a) Molding methods and materials (b) Melting techniques and solidification (c) gating and risering principles (d) finishing and fettling operations. 7. What is full mold process. Explain the process fully. What are the advantages disadvantages and applications of the above process. [16] 8. (a) Describe the various defects which are likely to be caused in sand castings because of higher pouring temperature. Suggest the remedial measures.[8+4+4] (b) Give the differences between the following sand casting defects from the stand point of their causes and medies. 1 of 2

Set No. 1

Code No: RR321803 i. Metal penetration and fusion ii. Rat tails and cuts and washes. ⋆⋆⋆⋆⋆

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Set No. 2

Code No: RR321803

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FOUNDRY TECHNOLOGY (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Describe the major activities in metal casitn industry through a flow-chart. [8+8] (b) Explain the major Research and development thrust areas of metal casting in India. 2. (a) Explain the importance of coal dust in the foundry sand.

[7+9]

(b) What is the need of core-print. What considerations are to be looked into the calculation of core-print size. 3. (a) Explain how the dies for the die casting are Manufactured.

[5+5+6]

(b) List the materials that are commonly used to make permanent molds. (c) Explain the low pressure permanent mold casting process and vacuum die casting process. 4. Distinguish between pressurized and non-pressurized gating system used in foundry shop. Explain with ’suitable examples. [16] 5. (a) Distinguish fully between Hamogeneous Nucleation and Heterogeneous Nucleation. [8+8] (b) Calculate the size of critical radius and the number of atoms in the critical radius the number of atoms in the critical nucleus when solid copper forms by homogeneous nucleation for the following data. Surface free energy σ = 177 × 10−3 J/m3 Freezing temp of copper = 10850 C Latent heat of fusion = 1628 × 106 J/m3 Under cooling temp = 2360 C Lattice parameter of Cu = 3.61SoA 6. (a) Explain the functions of deoxidesers added to copper melt.

[7+9]

(b) Describe the type of furnaces used for obtaining high purity copper used as electrical conductors. 7. (a) Explain with sketches how hollow sections are produced using the continuous casting process. [8+8] (b) Explain the salient advantages; limitations and applications of continuous casting process.

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Set No. 2

Code No: RR321803

8. (a) From which source do Blowholes appear to originate most frequently? Explain them. [8+8] (b) Explain specifically how mold restraint could contribute to hot tears in castings. ⋆⋆⋆⋆⋆

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Set No. 3

Code No: RR321803

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FOUNDRY TECHNOLOGY (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Compare the advantages and limitations of wood as pattern material to metals and plastics. [8+8] (b) What is the purpose of colouring patterns? Explain the common pattern colour code. 2. (a) Differentiate between foundry sand, core sand & synthetic sand.

[6+10]

(b) How do the suitability of moulding be judged for a specific job? Explain various sands used for Brasses; Bronzes, & Aluminium alloys. 3. Suggest a suitable casting process for the following items and justify your answer. (a) Hollow cylindrical pipes 200mm I.D., 250mm O.D. and 8000mm long. [6+5+5] (b) Spherical grinding media balls of 50mm diameter. (c) Bronze statues 4. (a) What are the requirements of good ‘gating’ and ‘risering’ system. Sketch various types of gate S: and explain them. [7+9] (b) A down sprue of 180 mm length has a diameter of 20 mm at its top end. The liquid metal in the pouring cup is maintained upto 60 mm height. What should be theoretical diameter of the down sprue at its lower end to ensure that there is no aspiration effect. 5. (a) Derive an expression for critical nucleus size during nucleation.

[8+8]

(b) Distinguish between progressive solidification and directional solidification. 6. (a) What type of cast iron family is suitable for malleabilising?

[4+6+6]

(b) Explain in detail mechanism and cycle of Malleabilising. (c) What are the ways of reducing malleabilizing cycle time. Explain them. 7. What is full mold process. Explain the process fully. What are the advantages disadvantages and applications of the above process. [16] 8. (a) What are the defects caused by low pouring temperature.

[7+9]

(b) Explain from which source gasholes and blowholes appear to originate most frequently. ⋆⋆⋆⋆⋆

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Set No. 4

Code No: RR321803

III B.Tech Supplimentary Examinations, Aug/Sep 2008 FOUNDRY TECHNOLOGY (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Explain how metal casting units (Foundries) are classified.

[8+8]

(b) Explain the various steps involved in making a casting. 2. Name the ingredient commonly mixed in the molding sands and the properties contributed by each of them. [16] 3. (a) Discuss in detail the principle operation, advantages and limitations of CO2 process. [6+6+4] (b) Is it possible to obtain a sound casting of a solid bar by centrifugal casting? Give reasons in support of your answer. (c) Explain why most die castings not made out of high strength materials. 4. (a) What do you mean by centre line feeding resistance. Explain its importance in solidification of castings [8+8]. (b) Explain the importance of cores. 5. (a) Derive an expression for critical nucleus size during nucleation.

[8+8]

(b) Distinguish between progressive solidification and directional solidification. 6. Discuss the various raw materials required in cupola. How would you light the cupola. Discuss in detail the importance of coke bed height in cupola operation. [16] 7. What is full mold process. Explain the process fully. What are the advantages disadvantages and applications of the above process. [16] 8. (a) From which source do Blowholes appear to originate most frequently? Explain them. [8+8] (b) Explain specifically how mold restraint could contribute to hot tears in castings. ⋆⋆⋆⋆⋆

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