Set No. 1

Code No: RR311805

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III B.Tech I Semester Supplimentary Examinations, November 2007 TECHNIQUES OF METAL JOINING (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Write a short notes on different types of welding positions. Give their advantages and limitations.

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(b) Classify the welding processes with proper explanation on the basis of the following. i. Source of heat ii. Type of interaction.

[8+8]

2. (a) Explain how oxy-acetylene torch can be used for welding process.

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(b) Explain fore hand and back hand welding techniques in gas welding process with diagrams and give their relative advantages. [7+9] 3. (a) Name the various shielding gases used in inert gas arc welding methods. Discuss the relative merits and demerits of each one of them.

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(b) Compare and Contrast T IG welding and MIG welding processes.

[8+8]

4. (a) Sketch the Laser beam welding set up. Discuss the process. Give its applications. What are the advantages and limitation of the above process. (b) What are the various sources of Lasers? Explain them. Also give the energy density ranges of them. [10+6] 5. (a) What is weldability? Explain how and on what basis weldability can be assessed.

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(b) Discuss in detail the welding of stainless steels and other high alloyed steels. [8+8]

6. (a) What is wettability? How the wetting behavior of material against a particular substrate is determined? Explain with suitable examples.

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(b) How the high electrical and thermal conductivities of copper and copper alloys have effect on their weldability? Explain. [8+8]

7. Write an essay on weld defects, their origin and their control.

[16]

8. (a) Differentiate fully between welding, brazing and soldering. (b) What is a flux? What is the use of a flux in a brazing process? Explain the various fluxes used in brazing process. [8+8] ⋆⋆⋆⋆⋆ 1 of 1

Set No. 2

Code No: RR311805

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III B.Tech I Semester Supplimentary Examinations, November 2007 TECHNIQUES OF METAL JOINING (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What is welding? Write a detailed account on the history and development of welding techniques.

[10+6]

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(b) Explain the advantages and disadvantages of welding processes.

2. (a) Explain the steps involved in the preparation of pieces for gas welding process. Explain how the weld quality is affected by the quality of the edge preparation. (b) Name 2 gas welding techniques and, explain their principle and applications. [10+6]

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3. (a) Draw a neat sketch of the arrangement of the equipment in TIG welding process. Lable the different parts and explain the function of each part. Name and explain the shielding gases you suggest for TIG welding process.

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(b) Sketch and explain different types of metal transfer in arc welding process. [10+6] 4. (a) Explain the resistance spot welding with suitable diagrams for Force Vs time and Current Vs Time. Give the advantages and applications of this process. (b) Why is resistance welding called solid state welding process? Write down the sequence of steps involved in resistance spot welding process. [10+6] 5. (a) What is ‘weld decay’ in austenitic stainless steel welds? Explain them. (b) What are the principle factors responsible for it? Explain them.

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(c) What are the various methods available to control it? Explain.

[5+5+6]

6. Explain the welding processes for, welding of Aluminium & Copper alloy components. [16]

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7. (a) What do you mean by welding joint. What are the various types of welded joints. (b) How are they classified. (c) Explain all of them with neat sketches.

[5+4+7]

8. Describe in detail the scope, technique, mechanism and nature of bond formation during welding, soldering and brazing processes. [16] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: RR311805

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III B.Tech I Semester Supplimentary Examinations, November 2007 TECHNIQUES OF METAL JOINING (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Explain forehand and backhand welding techniques in gas welding (with neat sketches). Give their relative advantages and limitations.

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(b) What are the conditions required for an ideal metallurgical bond? Explain them in detail. [10+6] 2. (a) State the approximate pressure of acetylene in a fully charged cylinder.

(b) What is the maximum possible pressure at which acetylene may be used for welding or cutting operations? Explain.

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(c) What equipment is required for atomic hydrogen welding? Explain the power source, gas supply, torch, electrodes and filler rods. [2+3+11] 3. (a) Distinguish fully between gas welding and arc welding with respect to the principle. operation, application and limitations.

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(b) With a neat sketch, explain the MIG welding process. What are the advantages of the method. [8+8] 4. (a) Explain why a flux is not required for resistance spot welding process. (b) Give three possible causes of a defective resistance spot welds. Also suggest remedial measures for the same. (c) Explain the differences in the application and relative advantages of laser beam welding and electron beam welding. [4+5+7]

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5. (a) Discuss on welding and weldability of Nickel-Cobalt high alloy steels. (b) Explain about the welding of maraging steels.

[8+8]

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6. (a) What are the major problems encountered in welding of aluminium alloys. Explain then fully. (b) Explain the following in the welding of aluminim and its alloys i. Liquiation cracking ii. Stress corrosion cracking

[8+4+4]

7. (a) What do you mean by welding joint. What are the various types of welded joints. (b) How are they classified. (c) Explain all of them with neat sketches. 1 of 2

[5+4+7]

Set No. 3

Code No: RR311805

8. (a) Differentiate fully between welding, brazing and soldering. (b) What is a flux? What is the use of a flux in a brazing process? Explain the various fluxes used in brazing process. [8+8]

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Set No. 4

Code No: RR311805

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III B.Tech I Semester Supplimentary Examinations, November 2007 TECHNIQUES OF METAL JOINING (Metallurgy & Material Technology) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What is welding? Write a detailed account on the history and development of welding techniques.

[10+6]

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(b) Explain the advantages and disadvantages of welding processes.

2. (a) Explain how acetylene gas is stored in the cylinder. Discuss the safety devices incorporated in the cylinder.

(b) Name various types of flames used in gas welding process. Suggest their specific applications. Draw neat sketches of the flames. [7+9]

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3. (a) What is magnetic arc blow? Explain it. How it is minimized.

(b) Explain the reasons why damp flux coated electrodes should not be used for welding mild steel materials. [8+8]

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4. (a) Explain the resistance spot welding with suitable diagrams for Force Vs time and Current Vs Time. Give the advantages and applications of this process. (b) Why is resistance welding called solid state welding process? Write down the sequence of steps involved in resistance spot welding process. [10+6] 5. (a) What is weldability? Explain how and on what basis weldability can be assessed.

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(b) Discuss in detail the welding of stainless steels and other high alloyed steels. [8+8] 6. (a) What are the major problems encountered in welding of aluminium alloys. Explain then fully. (b) Explain the following in the welding of aluminim and its alloys

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i. Liquiation cracking ii. Stress corrosion cracking

[8+4+4]

7. Explain with sketches the following types of weld defects (a) Under cut

(b) Lack of fusion (c) Lack of penetration (d) Porosity.

[4×4=16]

8. Compare and contrast the following 1 of 2

Set No. 4

Code No: RR311805 (a) Soldering and Brazing (b) Soft solders and hard solders (c) Brazing & Braze welding.

[5+5+6]

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2 of 2