R05322003-metal-forming

Set No. 1

Code No: R05322003

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 METAL FORMING (Production Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Write short notes on the following: (a) anlastic behaviour (b) Toughness (c) yield criteria (d) ultimate tensile strength.

[4×4]

2. (a) Explain the effects of % cold work on the formability of the material. (b) Explain the effects of the following on the recry stallization temperature. i) additiion of alloying elements ii) Purity of metals ii) Grain size. [6+10] 3. Distingnish between hot working and coldworking by taking machanical and metallurgical properties of metals into consideration. [16] 4. (a) Name the various methods by which sheet metal blanks can be cut from a large sheet. Explain them. (b) What is a forming-limit diagram. What are its advantages and disadvantages. What are the features of forming-limit diagram. [8+8] 5. (a) Compare forging hammers with presses and mention the characteristics of a forging machine. (b) A right circular cylindrical steel with flow of its stress of 5 Kg/mm2 , 75mm height and 25mm diameter has to be upset to half height between flat dies. What is the maximum pressure required for upsetting, if coefficient of friction is 0.4. (c) What is PM forging? What are its advantages. 6. (a) Explain the following: i. ii. iii. iv. v.

Roll forming Tandum mill Angle of nip No slip angle Redundant work

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[7+5+4]

Set No. 1

Code No: R05322003

(b) What is the effect of presence of front and back tensions in rolling load? Explain. [12+4] 7. (a) Explain briefly the classification of extrusion processes. (b) Discuss in detail the Hot extrusion process. (c) Describe in brief the deformation in extrusion.

[5+7+4]

8. (a) Draw the cross section of a drawing die and explain the various parts in it. (b) Explain the follwoing i. Tube sinking ii. Patenting [8+8] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: R05322003

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 METAL FORMING (Production Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Write short notes on the following: (a) Yield locus (b) Levy-Mises equations(Flow rules).

[8+8]

2. (a) What is hot working? Is it possible to have hot working of metals at room temperature? How? Explain with suitable examples. (b) Assume that a tapered piece of copper has been stressed in tension beyond its yield point and then annealed. Explain how the grain size will change along the taper. [8+8] 3. Define hot working, warm working and cold working.Discuss the relative features of hot work and cold work for Al, Pt and Molybdenum considering melting point, brittleness and oxidation behaviour. [16] 4. Explain the following: (a) Compound die (b) Combination die (c) Progressive die (d) Transfer die.

[4×4]

5. (a) What is Forging? Describe various types of forging dies. (b) Sketch and describe counter flow forging hammer. (c) Discuss the advantages and limitations of forging process.

[7+4+5]

6. (a) Maximum draft in rolling is decided by coefficient of friction. Explain. (b) Define Torue and power required for rolling. Describe how they can be estimated. (c) Calculate the rolling load if steel sheet is hot rolled 30 percent from a 40mmthick slab using a 900 mm-diameter roll. The slab is 760 mm wide. Assume µ = 0.30. The plane-strain flow stress is 140 Mpa at entrance and 200 Mpa at the exit from the roll gap due to the increasing velocity. [5+6+5] 7. (a) Describe the common extrusion equipment and basic elements of an extrusion die. (b) Briefly explain the deformation and flow of metal during extrusion. 1 of 2

[10+6]

Set No. 2

Code No: R05322003 8. Discuss the following:

[8+8]

(a) Production of tubes and seamless pipes. (b) Rod and wire drawing processes. ⋆⋆⋆⋆⋆

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Set No. 3

Code No: R05322003

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 METAL FORMING (Production Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) State the maximum shear stress criterion and derive it. (b) Explain why the elastic deformation does not disappear, even after the load which had caused plastic deformation in polycrystalline materal is relased. [8+8] 2. (a) Explain why is it neded to perform annealing during cold working process. (b) Draw a typical recrystalization curve representing ii) % of recrystallization, and iii) time of annealing. Explain about the curve.

[8+8]

3. Define hot working, warm working and cold working.Discuss the relative features of hot work and cold work for Al, Pt and Molybdenum considering melting point, brittleness and oxidation behaviour. [16] 4. (a) Explain the differeces between i. drwing and ii. deep drawing (b) Expalin why normal anisotrophy is important in determining the deep drwawability of a material . [8+8] 5. (a) Distinguish between press forged and drop forged components. (b) Discuss the forging process in plane strain condition. (c) A 13kN power-forging hammer has a total nominal energy of 47 kJ. If the blow efficiency is 40 percent and the forging load builds up from P/3 at the beginning of the stoke to P at the end of the stroke, what is the total forging load for i. a stroke of 5mm ii. a stroke of 15mm.

[6+4+6]

6. (a) Explain the following: i. ii. iii. iv. v.

Roll forming Tandum mill Angle of nip No slip angle Redundant work 1 of 2

Set No. 3

Code No: R05322003

(b) What is the effect of presence of front and back tensions in rolling load? Explain. [12+4] 7. (a) Calculate the force required in extruding a copper alloy at 7500 C, if the billet diameter is 80 mm and the extrusion ratio is 20. (b) Explain the term ‘efficiency of a forming process’ in terms of energy consumed. (c) What is the significance of grain size control for metal forming?

[6+5+5]

8. (a) Explain about the residual stresses in rods, wires and tubes drawn. (b) Discuss the effects of the following on maximum possible reduction in wire drawing with no back tension. i. Cone angle ii. Friction

[10+6] ⋆⋆⋆⋆⋆

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Set No. 4

Code No: R05322003

III B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 METAL FORMING (Production Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Explain why plastic deformation arrests the fracure of a part. (b) Distigunish between the terms total elongation and uniform elongation. (c) Explain about the ‘NECKING’ phenomena.

[5+4+7]

2. (a) Why is it necessary to have a lubricating system in plastic deformation proceses and what are the various lubricating systems used in metal forming units. Explain them. (b) Explain the various property and structural changes that take place when a cold worked metal is heated continuously. [8+8] 3. (a) What is the alloy which has highest observed elongation as a superplastic material. Explain in detail. (b) What are the two kind of superplasticity. Explain them in detail. (c) At what strain rates and temperatures, superplastic deformation takes place. [5+8+3] 4. (a) How does sheet metal forming difffer from roling, forging and extrusion? Explain in detail. (b) Explain the differences between punching and blannking

[8+8]

5. (a) Elaborate on i. presses and ii. hammers used in forging. (b) Define clearly the Flash and draft in forging and mention their significance at appropriate places. (c) Draw neat diagrams of forging equipment and indicate their characteristics features. [5+4+7] 6. Write short explanatory notes on the following: (a) Roll of friction in rolling (b) Three-high mill (c) Horse power in rolling (d) Theories of cold rolling.

1 of 2

[3+3+4+6]

Set No. 4

Code No: R05322003

7. (a) Explain how extrusion speed and temperature can be selected for hot extrusion. (b) Explain residual stresses in tubes. (c) Explain about Impact extrusion process. 8. Discuss the following:

[6+5+5] [8+8]

(a) Production of tubes and seamless pipes. (b) Rod and wire drawing processes. ⋆⋆⋆⋆⋆

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