Deck 18: Gas Tungsten Arc Welding of Pipe

Question 1

To purge the air out of a 10-foot section of 6-inch diameter pipe, if the flow rate is 20 cfh, the flow time will be approximately ____.

A) 3 minutes
B) 6 minutes
C) 7 minutes
D) 9 minutes

Answer 1

B

Question 2

____ help to reduce the number of repairs or rejections when welding under less than ideal conditions, such as in a limited space.

A) Consumable inserts
B) Tack welds
C) Backing strips
D) Preplaced filler rods

Answer 2

A

Question 3

The end of the pipe is prepared with a bevel, leaving a root face of ____ inch.

A) 1/16 to 1/8
B) 1/16 to 1/4
C) 3/32 to 1/8
D) 1/8 to 1/4

Answer 3

A

Question 4

Incomplete fusion can be detected by ____.

A) an X-ray
B) a root-bend test
C) visual inspection
D) cutting a cross-section of the weld

Question 5

Both the ____ and the ____ can be easily flame cut or ground, which makes them the most frequently used groove joints for training.

A) single V-groove, single U-groove
B) single U-groove, single bevel-groove
C) single V-groove, single bevel-groove
D) single J-groove, single U-groove

Question 6

____ result(s) from excessive heat, temperature, and filler metal during welding.

A) Porosity
B) Grapes
C) Suck back
D) Incomplete penetration

Question 7

Which of the following is a measure of root reinforcement?

A) Percentage of the total weld width
B) The smallest number and smallest size of spots per inch of weld
C) Percentage of the effective throat
D) The maximum distance from the metal surface to the longest spot of excessive reinforcement

Question 8

Which of the following is a common cause of a concave root surface?

A) Insufficient filler metal
B) Insufficient heat
C) Poor shielding
D) Contamination of the weld surface

Question 9

Which of the following is a cause of contamination of the back side of the molten weld pool?

A) Failure to remove the root edge
B) Insufficient heat, insufficient filler metal
C) Overheating, poor cleaning procedures
D) Excessive root reinforcement

Question 10

Before the joint is assembled, to remove any sources of contamination, clean a ____ inch wide or wider band, both inside and outside of the pipe.

A) ½
B) 1
C) 1 ½
D) 2

Question 11

____ can result in premature cracking or failure of the weld at a load well under its expected strength.

A) Porosity
B) Contamination
C) Stress points
D) Oxidization

Question 12

To contain backing gas in a pipe of small diameter, or short sections of pipe, ____.

A) the ends of the pipe are capped
B) the pipe is plugged on either side of the weld
C) the pipe is plugged using water-soluble plugs
D) the pipe is plugged using soft plastic bags

Question 13

____ can be used to back any type of pipe if a welder is unsure about a less expensive substitution.

A) Nitrogen
B) Carbon dioxide
C) Oxygen
D) Argon

Question 14

What is the most commonly used groove shape for pipe?

A) V-groove
B) U-groove
C) S ingle bevel-groove
D) J-groove

Question 15

Most codes and standards for GTA pipe welding require no more than ____ inch of root reinforcement.

A) 1/16
B) 3/32
C) 1/8
D) 1/4

Question 16

The end of the pipe is prepared with a ____ bevel.

A) 15 degree
B) 17 1/2 degree
C) 30 degree
D) 37 1/2 degree

Question 17

What might affect the selection of the type of groove preparation on the end of a pipe?

A) Pipe material
B) Pipe application
C) Pipe thickness
D) All of the above

Question 18

In preparing the pipe for welding, the pipe should be tack welded together with a root opening of ____ inch.

A) 1/16 to 1/8
B) 1/16 to 1/4
C) 3/32 to 1/8
D) 1/8 to 1/4

Question 19

The amount of concavity in a root surface can be given as ____.

A) a percentage of the total weld width
B) the smallest number and smallest size of spots per inch of weld
C) a percentage of the effective throat
D) a percentage of the width at the narrowest point

Question 20

After the bevel has been cut, the root face is created by ____.

A) the bevel itself
B) grinding or machining the root edge
C) cutting a suitable gap in the pipe
D) cutting a U-groove

Question 21

The easiest method of protecting the root from atmospheric contamination is to use a(n) ____________________.

Question 22

What can be done to make it easier to set the root opening for tack welding?

A) Bend a piece of filler rod in a U-shape and place it between the ends of the pipes.
B) Use a piece of tungsten as a spacer because it will not melt and it is hard enough to resist the forces of the tack weld bead shrinking.
C) Measure the gap carefully with a steel rule or tape measure.
D) Using a smaller diameter nozzle cup, place it in the groove to keep the pipe ends spaced as the tack weld is made.

Question 23

What is the weld pass that can correct some of the problems with the root pass?

A) Hot pass
B) Filler pass
C) Fillet weld
D) Backing weld pass

Question 24

The ____________________ is the distance between the original surface of the joint and the deepest point of fusion.

Question 25

Why are the ends of tack welds ground to a featheredge?

A) It makes it easier to see as you weld across the tack welds.
B) It prevents the shielding gas from becoming turbulent and losing good gas coverage.
C) It stops porosity.
D) It makes it easier to have 100% penetration at the ending and beginning of the root weld.

Question 26

The ____________________ is the amount of metal deposited on the back side of a welded joint.

Question 27

The ____________________ is the next weld layer(s) to be made after the hot pass.

Question 28

Define concave root surface and list its common causes and consequences.

Question 29

Explain how to compute the flow time necessary for backing gas to purge a pipe of air.

Question 30

Explain why the root edge must be removed when preparing a pipe for welding.

Question 31

Uneven buildup and burnthrough are sometimes referred to as ____________________.

Question 32

Explain how to use a hot pass to correct incomplete fusion.

Question 33

The ____________________ of the root surface results in reduced thickness of the weld.

Question 34

For a similar feel to walking the cup on a V-groove, practice walking a roll of ____________________ w ith a 2 in. by 2 in. (50 x 50 mm) or larger angle iron.

Question 35

What is an advantage of bending the welding rod to the radius of the pipe?

A) It makes the rod easier to hold and less likely to slip in the welder's gloved hand.
B) That way when the weld is stopped it is easier to see which end of the rod might be hot.
C) It allows the rod to be held at a closer angle to the pipe to minimize contamination.
D) It covers the joint to help to prevent incomplete fusion caused by the loss of the backing gas.

Question 36

A concave root surface is sometimes known as ____________________.

Question 37

The ____________________ of a weld is the deepest point into the joint where fusion between the base metal and the filler metal occurs.

Question 38

Describe the specifications of the stringer bead used to cap the weld in a cover pass.

Question 39

What welding technique can be used to reduce fatigue, improve torch control, and make longer, high-quality welds?

A) Backhand welding
B) Forehand welding
C) Cup walking
D) No technique; GTA welding is always very tiring.

Question 40

Excessive root reinforcement can cause reduced material flow, result in clogged pipes, or form ____________________ that will result in premature weld failure.