Mechanical Behaviour Questions and Answers – Formability

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This set of Mechanical Behaviour Multiple Choice Questions & Answers (MCQs) focuses on “Formability”.

1. The ability of a metal workpiece to undergo plastic deformation without being damaged is known as ____
a) Formability
b) Stiffness
c) Resilience
d) Yield strength
View Answer

Answer: a
Explanation: Formability is the ability of a metal to undergo plastic deformation without being damaged. Stiffness is resistance to elastic deflection. Resilience is energy absorbed when the material is deformed elastically.
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2. Which instrument is used to measure formability?
a) Universal testing machine
b) Impact testing machine
c) Erichsen machine
d) Fatigue testing machine
View Answer

Answer: c
Explanation: Erichsen machine is used to measure formability of sheet metal. UTM is used to measure strength. Fatigue testing machine is used to measure fatigue strength and impact testing machine to measure impact strength.

3. What is the reason of orange-peel effect?
a) Coarse grain structure
b) Fine grain structure
c) Inclusions
d) Impurities
View Answer

Answer: a
Explanation: Grain size greatly affects deep drawing. Coarse grain size gives the rough surface appearance. It is known as orange-peel effect.

4. ______ increases the formability of the metal sheet.
a) Annealing
b) Cold working
c) Inclusions
d) Grain coarsening
View Answer

Answer: a
Explanation: Annealing causes recrystallization in sheet metal reducing stresses. It hence improves formability. Cold working and inclusions decrease formability.

5. Erichsen value of formability ______ with the thickness of the metal sheet.
a) Increases
b) Decreases
c) Remains constant
d) First increases and then decreases
View Answer

Answer: a
Explanation: With an increase in thickness of the sheet, the extent to which it can plastically deform increases. Thus the formability increases.
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6. Formability of sheet metal ____ with an increase in normal anisotropy.
a) Increases
b) Decreases
c) Remains constant
d) Varies independently
View Answer

Answer: a
Explanation: With an increase in normal anisotropy, the flow stress of material decreases. Decreased flow stress increases the strength of the cup section. Thus formability increases with normal anisotropy.

7. In the _____ test, the specimen is bent between two rollers until an angle between 30° to 45° is reached.
a) Free bending test
b) Olsen cup test
c) Swift cup test
d) Fukui conical cup test
View Answer

Answer: a
Explanation: Free bending test is performed by bending the specimen to 30° to 45° angle. Observations are made to see whether cracks are formed. Olsen, Swift and Fukui conical cup tests are performed by measuring cupping value.

8. What is the value of lankford coefficient (r) for good deep drawable material?
a) ≤ 1
b) ≤ 2
c) ≤ 3
d) ≤ 4
View Answer

Answer: b
Explanation: Lankford coefficient is a specific material property. It is the ratio of width deformation to thickness deformation in a uniaxial tensile test. It should be equal to or below 2 for good deep drawability.

9. Inclusions don’t affect formability of materials.
a) True
b) False
View Answer

Answer: b
Explanation: Impurities become elongated during rolling. These are known as stringers. These can cause the sheet to fail by cracking.
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10. Lack of symmetry in crack shows anisotropy in a material.
a) True
b) False
View Answer

Answer: a
Explanation: Type of crack formed is used to identify the directional property of a material. Lack of symmetry shows anisotropy. Anisotropy tells the different properties in different directions.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn