Manufacturing Engineering Questions & Answers – Forming

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This set of Manufacturing Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Forming”.

1. Depending upon the temperature the forming process can be classified as?
a) Hot working
b) Cold working
c) Warm working
d) All of the mentioned
View Answer

Answer: d
Explanation: Depending upon the temperature the forming process can be classified as hot working, cold working, and warm working.
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2. If Tm is the melting temperature, then in hot working the value for that material is?
a) 0.5 Tm
b) 0.6 Tm
c) 0.4 Tm
d) 0.7 Tm
View Answer

Answer: b
Explanation: If Tm is the melting temperature then in hot working the value of Tm is .6 Tm. Hot working is done above recrystallization temperature.

3. In which of the following process no strain hardening is produced?
a) Hot working
b) Cold working
c) Warm working
d) Cannot say
View Answer

Answer: a
Explanation: In hot working (working above recrystallization temperature), no strain hardening is produced, this is because, when hot working is done, there is simultaneous recrystallization and grain growth due to elevated temperature. So, the material regains its ductility and there is no residual stress in the material.
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4. During hot working, the grain growth can take place in which part of the material?
a) Exterior
b) Interior
c) Along the edges
d) Side faces
View Answer

Answer: b
Explanation: During hot working, the grain growth can take place in the interior part of the material because the interior part cools slowly the remaining parts.

5. Which of the following defect is eliminated by hot working process?
a) Cold shut
b) Misrun
c) Blow holes
d) Fusion
View Answer

Answer: c
Explanation: Blow holes and porosities can be eliminated at high temperature, thus in hot working process.
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6. The working temperature of cold working is below a certain temperature. That temperature is known as?
a) Critical temperature
b) Recrystallization temperature
c) Transition temperature
d) Curie temperature
View Answer

Answer: b
Explanation: Recrystallization temperature is generally defined as temeprature at which complete recrystallization occurs within approximately one hour, in other sense, recrystallization temperature of a given metal is about one-half its melting point (0.5 Tm) as measured on an absolute temperature scale.

7. In which of the following process the ductility of material decreases?
a) Hot working
b) Cold working
c) Warm working
d) Cannot say
View Answer

Answer: b
Explanation: Cold working is the work done below recrystallization temperature. As cold work is increased, yield strength and tensile strength increases, percentage of ductility decreases.
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8. Which of the following statement is true about cold working?
a) Strain hardening is relieved
b) No oxidation occurs
c) Only limited amount of reduction can be done
d) Cost of machining is high
View Answer

Answer: a
Explanation: A comparison of hot and cold working are tabulated below:

S.No. Hot Working Cold Working
1. Working above recrystallization temperature Working below recrystallization temperature
2. Formation of new crystals (grains) No crystal formation
3. Surface finish is not good Surface finish is good
4. No stress formation Internal stress developed
5. Improved mechanical property due to grain formation Leads to distortion of metal grains
6. Closed dimensional tolerances cannot be maintained Superior dimensions can be obtained
7. Improves some mechanical properties like, impact strength and elongation During process, strength and elongation decreases

9. In which of the following process plastic deformation takes place?
a) Cold working
b) Hot working
c) Both cold working and hot working
d) Cannot say
View Answer

Answer: c
Explanation: Operations that induce shape changes on the workpiece by plastic deformation under forces applied by various tools and dies are termed as plastic deformation processes. Plastic deformation of metals below the recrystallization temperature is known as cold working and the plastic deformation carried above recrystallization temperature is termed as hot working.
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10. In metal forming process the hardness of the material?
a) Decreases
b) Remains same
c) Initially increases and then decreases
d) Increases
View Answer

Answer: d
Explanation: When metal is formed in cold stat, there is no recrystallization of grains and thus recovery of grains and thus recovery from grain distortion or fragmentation does not take place. As grain deformation proceeds, greater resistance to this action results in increased hardness and strength. The metal is said to be strain hardened.

11. The work involved with the internal shearing process due to non-uniform deformation is?
a) Ideal work
b) Frictional work
c) Redundant work
d) Slip work
View Answer

Answer: c
Explanation: Redundant work is the energy expended on deformation the body which is not involved in a pure change in shape, in other sense, the redundant work is the work involved in internal shearing processes due to non-uniform deformation that does not contribute directly to change in shape of the body.

12. Which of the following method is used for analyzing metal forming processes?
a) Slab method
b) Upper bound method
c) Slip line method
d) All of the mentioned
View Answer

Answer: d
Explanation: There are two kinds of mode of analyses i. analytical numerical methods, ii. empirical methods. The methods such as elementary theory (slab method), slip line field theory, finite element method (FEM), finite difference method (FDM) and upper & lower bound method are the types of analytical numerical methods. Similarity theory and visco-plastic method are of empirical methods.

13. Which of the following method is commonly used for analyzing metal forming processes?
a) Slab method
b) Upper bound method
c) Slip line method
d) Empirical method
View Answer

Answer: a
Explanation: Out of all analysing methods, perhaps, slab method (elementary theory) is commonly used and is a simple analytical procedure based on principles of mechanism.

14. Warm working is done at a temperature?
a) Above re crystallization temperature
b) Below re crystallization temperature
c) Equal to re crystallization temperature
d) Below re crystallization temperature and above room temperature
View Answer

Answer: d
Explanation: Warm working is done at a temperature below recrystallization temperature and above room temperature. In warm working some strain hardening or precipitation hardening may occur. Usual warm working temperature is of 0.3Tm to 0.5 Tm.

15. Which process got a better dimensional accuracy?
a) Hot working
b) Cold working
c) Warm working
d) Both Hot working and Cold working
View Answer

Answer: a
Explanation: In cold working metal is shaped by the application of pressure at temperature below recrystallization temperature of the metal. In most cases it is done at room temperature. This is done to achieve close dimensions and accuracies and to improve mechanical properties. It is often done after hot working to obtain better dimensional control.

Sanfoundry Global Education & Learning Series – Manufacturing Engineering.

To practice all areas of Manufacturing Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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