Chapter 14 - Welding Techniques

Question 1

Major advantage of SMAW welding?
A) precision
B) ability to weld in every position
C) PPE required to weld
D) low cost and ease of handling

Answer 1

D

Question 2

What is the major disadvantage of SMAW welding?

Answer 2

intense heat and radiation produced, resulting in the use of dark-lensed helmets

Question 3

What do the first two numbers denote in the AWS Electrode classification E7018?
A) 70 PSI
B) 7000 PSI
C) 70 000 PSI
D) 70 welding positions

Answer 3

C. (tensile strength in the as-welded condition)

Question 4

What does the last digit of an AWS/CSA classification indicate?

Answer 4

Type of current, coating, and polarity

Question 5

What Position is SAW welding only used in? For what kind of sections?

Answer 5

Flat, thick sections in the horizontal position. (used highly in structural steel/pressure vessels)

Question 6

Define deposition rate in welding.

Answer 6

Amount of weld metal deposited per unit of time

Question 7

Pick two major advantages of SAW welding, over other types of welding.
A) more economical
B) very high deposition rate
C) elimination of nitrides and oxides in the weld
D) high heat inputs
E) Minimal operator training required

Answer 7

B and C. D is a major DISadvantage.

Question 8

SAW welding can be semi or fully automatic.
T or F

Answer 8

True.

Question 9

How does SAW welding result in welds with potential for hydrogen cracking?

Answer 9

flux absorbs moisture -> transfers to the deposit -> hydrogen cracking after the weld has cooled.

Question 10

What role does gravity play in the SAW welding process?

Answer 10

pulls flux down onto the top of the weld/arc. this is why we are in horizontal position only

Question 11

The Arc in GTAW melts what?
A) tungsten electrode
B) filler rod
C) flux
D) base metal

Answer 11

D

Question 12

What is the primary use case for GTAW welding?

Answer 12

difficult to weld metals (like nonferrous and highly alloyed steel), where high quality welds are required

Question 13

Which of the following is NOT an advantage of GTAW?
A) Can weld dissimilar metals
B) Base material can be handled in any way
C) can weld thin metals
D) extremely clean process

Answer 13

B

Question 14

Name any 2 disadvantages of GTAW.

Answer 14

Need high operator skill, must keep base metal extremely clean, must keep filler metal extremely clean, requires back purging, must be careful not to lose coverage gas

Question 15

Which welding type is the only arc welding type that is suited to welding all commercial ferrous and non-ferrous alloys?
A) GMAW
B) GTAW
C) SAW
D) SMAW

Answer 15

A

Question 16

What is the difference in electrodes between Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW)?

Answer 16

Gas tungsten electrodes are non-consumable, gas metal electrodes are consumable.

Question 17

GMAW is a __________ production, __________ quality weld technique.
A) High, Low
B) Low, High
C) Low, Low
D) high, high

Answer 17

D

Question 18

Describe the role of G (gas) in GTAW and GMAW welding.

Answer 18

Gas is like a blanket around the work to keep the atmosphere from touching and potentially contaminating the weld.

Question 19

SMAW is also known as?
A) butt welding
B) flange welding
C) man welding
D) stick welding

Answer 19

D

Question 20

What size of piping requires a butt weld?
A) greater than 51 mm
B) less than 51 mm
C) greater than 33 mm
D) less than 33 mm

Answer 20

A

Question 21

Be able to identify the root opening, root face, groove face, bevel angle, groove angle, size of weld, and pipe thickness on a weld diagram.

Answer 21

hope u know it

Question 22

Why do we preheat and postheat welding material?

Answer 22

to minimize the stress due to the temperature gradient in t he work.

Question 23

Be able to identify pictures of undercut, Lack of penetration/fusion, overlap, underfill, porosity, slag inclusion

Answer 23

pics

Question 24

What causes porosity in a weld?

Answer 24

gases trapped inside the weld

Question 25

which is NOT a way to classify weld cracks? A) Surface/subsurface B) weld and heat affected C) hot and cold D) fracture/discontinuity

Answer 25

D

Question 26

Explain the mechanisms of hot and cold cracking.

Answer 26

Hot = caused by shrinkage stress Cold = caused by gases evolving after cooling. Both are in the cooldown phase, but cold cracking is when the metal is cold cold.

Question 27

Which is NOT a factor in the formation of hydrogen cracking? A) presence of hydrogen in the weld (from moisture) B) temperature below 200 C C) stress where the crack originates D) temperature below 100 C

Answer 27

B

Question 28

What type of flaw is principally detected by LPT? (liquid testing)

Answer 28

Flaws open to the surface

Question 29

LPT (liquid testing) is based upon which principle?

Answer 29

Capillary action

Question 30

What types of flaws can magnetic particle testing detect? What type of materials does MT only work on?

Answer 30

Surface or subsurface. Only works on ferromagnetic materials (duh)

Question 31

What principle is magnetic testing based on?

Answer 31

discontinuities distort the magnetic flux passed through them

Question 32

Put these steps in order to complete magnetic testing. 1) post cleaning 2) Pre-demagnetization of component 3)interpretation 4) magnetization of the component 5) application of magnetic particles 6) pre-cleaning 7) post-demagnetization of component

Answer 32

6, 2, 4, 5, 3, 7, 1.

Question 33

Which method of testing can detect flaws on the internal surface? A) FT B) MT C) RT D) UT

Answer 33

C

Question 34

List 3 unique things to consider when performing RT.

Answer 34

Personnel safety, access to both sides of component, flaws must be large, setup time, selecting a source, flaws must be parallel to beam

Question 35

UT can detect both surface and _________ flaws A) small B) large C) internal D) subsurface

Answer 35

D

Question 36

Ultrasonic testing is often used for thickness measurement, with accuracy of better than 5%. T or F

Answer 36

F, accuracy is better than 1%.

Question 37

What is a procedure qualification?

Answer 37

A test of a WELD to determine if it has the required characteristics for its use.

Question 38

What is a performance qualification/clarification?

Answer 38

A test of a welder to determine if they can make sound welds. Administered by inspector.