JNTU B.Tech II Semester Examinations, METAL FORMING, Aug/Sep 2008

JNTU B.Tech II Semester Examinations, METAL FORMING, Aug/Sep 2008

(Production Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

SET-I

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. [7+5+4]

 

6. (a) Explain the following:

i. Roll forming

ii. Tandum mill

iii. Angle of nip

iv. No slip angle

v. Redundant work

(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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