Chapter 8 Mechanical Testing of Welds

Question 1

1. What are the three ways in which a load can act on a cross-sectional area in a body?

a. tension, load and stress
b. shear, tension and strain
c. compressed, shear and pressure
d. tension, compression and torsion/shear

Answer 1

d. tension, compression and torsion/shear

Question 2

2. The strain in a body is a measurement of:

a. shear load stresses applied to an object
b. stress loads under shear pressures
c. the change in dimensions due to the application of an applied load
d. a change in dimensions when subjected to side bend testing

Answer 2

c. the change in dimensions due to the application of an applied load

Question 3

3. If a thin bar of metal is subjected to a stress, it will deform and exhibit strain. If the stress does not exceed a certain limit what will happen to the bar?

a. The bar will return to its original dimensions
b. The bar will be stretched longer than the original dimensions
c. The bar will break
d. The bar will do nothing

Answer 3

a. The bar will return to its original dimensions

Question 4

4. What would happen if a sufficiently high stress, beyond the elastic limit, is applied to a metal bar?

a. The bar would heat up and deform
b. The bar will extend when loaded and return to its original length when load is removed
c. The bar will break due to high stresses
d. The bar will not return to its original length and contain a permanent set

Answer 4

d. The bar will not return to its original length and contain a permanent set

Question 5

5. What is the relationship between the value E and the stress and strain defined as?

a. Young’s Modulus
b. Stress and Strain Curve
c. Hooke’s Law
d. Yield Strength

Answer 5

c. Hooke’s Law

Question 6

6. With regards to tensile testing, when the stress rises to a maximum value it is known as?

a. Yield strength of the material
b. Elasticity limit of steel
c. Ultimate tensile strength
d. Stress, strain curve

Answer 6

c. Ultimate tensile strength

Question 7

7. In the tensile test of a metal, what does the term necking mean?

a. The deformation of a test specimen that occurs when the UTS is exceeded
b. The deformation of a test specimen before the YS in the necked region
c. The amount of stress that is applied at the yield point of the specimen
d. The reduction in length of the specimen

Answer 7

a. The deformation of a test specimen that occurs when the UTS is exceeded

Question 8

8. With regards to tensile testing, what is elongation?

a. It’s the hardness of the metal
b. It’s the yield strength
c. It’s the ultimate yield strength
d. It’s a measure of the ductility of the metal

Answer 8

d. It’s a measure of the ductility of the metal

Question 9

9. What is an extensometer used for in a tensile test?

a. To measure the extension of the test specimen after the test
b. To keep the specimen centered in the jaws
c. To measure the strain during the test
d. To determine the ultimate tensile strength

Answer 9

c. To measure the strain during the test

Question 10

10. In the Charpy test, if the pendulum swings through the specimen almost to its original height, what does this indicate?

a. The specimen is very tough, indicating a clean break
b. The specimen has low tensile strength
c. The specimen has great elongation and ductility
d. The specimen is brittle and has absorbed little energy

Answer 10

d. The specimen is brittle and has absorbed little energy

Question 11

11. What is the nick break test used for?

a. Revealing internal weld defects
b. Revealing the ductility of aluminum
c. Revealing the strength of different metal types
d. Revealing surface cracks in test specimens

Answer 11

a. Revealing internal weld defects

Question 12

12. CSA W47.1 uses the fillet weld break test to:

a. determine the load required to fracture the test specimen
b. reveal defects such as porosity, penetration or other criteria which would determine whether the test has been passed.
c. evaluate the weld toughness and ductility
d. evaluate the fillet weld size, throat and convexity

Answer 12

b. reveal defects such as porosity, penetration or other criteria which would determine whether the test has been passed.

Question 13

13. What happens to the notch in the Charpy specimen when it is struck by the pendulum?

a. The notch goes into compression, causing an initiation of fracture from the notch
b. Initiation of fracture from the notch is caused by the pendulum setting up a fatigue crack at the notch root
c. The notch goes into a twisGng moment, causing an initiation of torsion forces
d. The notch goes into tension, causing an initiation of fracture from the notch.

Answer 13

d. The notch goes into tension, causing an initiation of fracture from the notch.

Question 14

14. In carrying out the Charpy V-notch test, why is the specimen loaded into the anvil with a pair of special tongs?

a. Because the specimen is extremely hot
b. To facilitate location of the specimen in the machine
c. The specimen may have sharp edges from preparation
d. To keep from contaminating the specimen due to dirty hands or gloves

Answer 14

b. To facilitate location of the specimen in the machine

Question 15

15. When conducting impact tests on welds:

a. one specimen must be tested at each temperature
b. it is most important that the notch is orientated correctly
C. it is not important that the notch is machined from the exact location, only that it is from the weld
d. it is most important that the specimens are machined from the HAZ only

Answer 15

b. it is most important that the notch is orientated correctly

Question 16

16. The Drop Weight test evolved from certain observations. What were these?

a. Fractures in ship steels where initiation occurred from small brittle regions in the weld zone
b. Fractures in armored steels where fracture initiation occurred in blast zones
c. Fractures from slag inclusions in GTAW steel welds
d. Fractures initiated from gross porosity in SMAW steel welds

Answer 16

a. Fractures in ship steels where initiation occurred from small brittle regions in the weld zone

Question 17

17. A major advantage of the CTOD fracture mechanics test is?

a. It measures the toughness of the material of interest in joules
b. It does not depend on the type of material tested
c. It can help to assess the significance of flaws within a structure
d. It is independent of the chemical make-up of the material

Answer 17

c. It can help to assess the significance of flaws within a structure

Question 18

18. Fatigue failure occurs under:

a. Repeating or fluctuating loads
b. Very heavy loading stresses in one direction
c. Loading at low temperatures
d. When high ductile materials are loaded in compression

Answer 18

a. Repeating or fluctuating loads

Question 19

19. When using the fatigue test method, how many tests are usually necessary to get good data?

a. Only one test is required
b. Two tests are sufficient
c. Three tests containing the detail with a notch are required
d. Several tests are generally required to produce sufficient data points

Answer 19

d. Several tests are generally required to produce sufficient data points

Question 20

20. What is Creep testing?

a. Creep testing is low-temperature progressive deformation at static loads
b. Creep testing is used to determine the amount of elasticity in steel
c. Creep testing is high-temperature progressive deformation at constant stress
d. Creep testing is used only on non-metallic materials

Answer 20

c. Creep testing is high-temperature progressive deformation at constant stress

Question 21

21. What is another name for the most common Proof test method performed on pressure vessels?

a. Hydraulic testing
b. Creep testing
c. Electrostatic testing
d. Hydrostatic testing

Answer 21

d. Hydrostatic testing

Question 22

22. A Proof test on a pressure vessel is usually performed using which medium?

a. Nitrogen
b. Air
c. Water
d. Argon

Answer 22

c. Water

Question 23

23. Why are bleeder valves used in Proof testing of pressure vessels

a. To keep the air from venting during the filling operation
b. To allow a pressure gauge to be attached to the vessel
c. To permit venting out of air during the filling operation
d. To keep the water inside the vessel

Answer 23

c. To permit venting out of air during the filling operation

Question 24

24. The testing pressures for proof testing are usually called for by a code or by specification. Failing any specific instructions, the test pressure is usually:

a. one and one-half times the maximum working pressure of the vessel
b. one and one-eighth times the minimum working pressure of the vessel
c. two times the maximum working pressure of the vessel
d. the maximum working pressure of the vessel only

Answer 24

a. one and one-half times the maximum working pressure of the vessel

Question 25

25. Which code in Canada specifies the requirements for mechanical testing related to structural steel applications?

a. ASME section IX
b. CSA W47.1
c. CSA W47.2
d. CSA W4B.18

Answer 25

b. CSA W47.1

Question 26

26. The unit N/mm2 is equal to:

a. Mpa
b. Ksi
c. Psi
d. N/m’

Answer 26

a. Mpa

Question 27

27. When we pull a sample in the tensile testing machine, the surface has tension stresses acting on it but also has shear stresses acting on it as well.

a. Yes
b. No

Answer 27

a. Yes

Question 28

28. Plastic deformation happens before the yield point.

a. No
b. Yes

Answer 28

a. No

Question 29

29. What other terms do we use for permanent deformation?

a. Permanent set
b. Elastic behavior
c. Extension
d. Modulus of elasticity

Answer 29

a. Permanent set

Question 30

30. Transition temperature or transition range temperature refers to impact testing of welds and materials. If the transition temperature for a given weld is minus 20C, this means:

a. that the weld performs well below that temperature
b. that the weld can not perform well below this temperature
c. that the weld would have high ductility below —20 °C
d. that the weld would have low hardness below -20 °C

Answer 30

b. that the weld can not perform well below this temperature