This set of Testing of Materials Multiple Choice Questions & Answers (MCQs) focuses on “Vickers Hardness Test”.
1. ___________ Indenter is used in Vickers hardness test.
a) Hardened steel ball
b) Diamond ball
c) Diamond square pyramid
d) Tungsten carbide
View Answer
Explanation: Square based pyramid indenter is used in Vickers test. It is made of diamond. Face angle is 136°.
2. Vickers indenter has _________ angle between opposite faces of a diamond.
a) 90°
b) 120°
c) 136°
d) 180°
View Answer
Explanation: Vickers indenter is the square based pyramid. The angle between the faces is 136°. It is made of diamond.
3. Which standards define Vickers hardness test?
a) ASTM E92-72
b) ASTME10
c) ASTME19-74
d) ASTME334-69
View Answer
Explanation: Vickers hardness test is defined by ASTM standard E92-72. Brinell test is defined by ASTME10. Rockwell test is described by ASTM19-74.
4. Up to a Vickers hardness of _________ the VHN agrees with the BHN.
a) 30
b) 100
c) 350
d) 1000
View Answer
Explanation: Up to 350 Vickers hardness, VHN agrees with the BHN. It depends on the load under which the impression is made. Geometry of indenter is the reason behind this relation.
5. What is the disadvantage of the Vickers test?
a) Accurate readings
b) One type indenter for all type materials
c) Hardness above 450 BHN can be measured
d) Large floor-standing machines
View Answer
Explanation: Vickers hardness test has a disadvantage of large floor standing machine. It can overcome the limitations of the Brinell test. For example, hardness above 450 BHN can be measured.
6. Why Brinell and Vickers hardness test results show similarities?
a) Same material indenter
b) Geometrically similar indentations
c) Applied load is same
d) Same size indenter
View Answer
Explanation: Brinell test indenter is made of hardened steel. Vickers test indenter is made of diamond. These give geometrically similar indentations so the similar results.
7. One division of the main scale equals _________ in Vickers test.
a) 0.1 mm
b) 0.01 mm
c) 1.0 mm
d) 0.001 mm
View Answer
Explanation: One division of the main scale equals 0.1 mm. In Vernier scale, one division equals to 0.01 mm. It provides lowering of error.
8. Which of the following is an advantage of the Vickers test?
a) Rough surface preparation
b) Cheaper
c) Accurate readings
d) Large floor-standing machine
View Answer
Explanation: Because of well-defined surface indentation, accurate readings are obtained. This machine covers large space. It is expensive too.
9. What is Vickers hardness of martensite?
a) 140 VHN
b) 180 VHN
c) 1000 VHN
d) 1200 VHN
View Answer
Explanation: Martensite is a hard phase in steel. It has 1000 VHN hardness. It is because of dislocation hardening.
10. What is the hardness of the diamond in VHN?
a) 1000 HV
b) 1200 HV
c) 9000 HV
d) 10000 HV
View Answer
Explanation: Diamond is the hardest mineral. It has the hardness of 10000 HV. It can be understood by covalent bonding.
11. Yield strength is given as HV/0.3.
a) True
b) False
View Answer
Explanation: If HV expressed in kg/mm2, then σu = HV/0.3. It can also be written as σu = C * HV. Here, C is constant ranging from 2 to 4.
12. Thickness of sample doesn’t affect the Vickers test.
a) True
b) False
View Answer
Explanation: Thin samples indentation depth can cause substrate effects. So sample thickness should be kept greater than 2.5 times the indent diameter.
Sanfoundry Global Education & Learning Series – Mechanical Behaviour & Testing of Materials.
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