Deck 17: Gas Tungsten Arc Welding of Plate

Question 1

Exceeding the maximum gas flow rates ____.

A) saves time and reduces the cost
B) decreases weld contamination
C) causes weld contamination
D) decreases rejection rate

Answer 1

C

Question 2

____ is inexpensive and requires the least amount of cleaning.

A) Mild steel
B) Aluminum
C) Stainless steel
D) Low carbon steel

Answer 2

A

Question 3

An oxide layer on aluminum is ____, while on iron it is ____.

A) black, reddish
B) reddish, gray
C) white, black
D) white, reddish

Answer 3

A

Question 4

The ____ possible gas flow rates and the ____ preflow or postflow time can help reduce the cost of welding.

A) highest, shortest
B) lowest, shortest
C) highest, longest
D) lowest, longest

Question 5

In the GTAW process, contamination left on the metal will be deposited in the weld because ____.

A) the low arc temperature does not vaporize it
B) the low amperage does not allow it to be burned off
C) tungsten contamination is a constant problem that cannot be eliminated
D) there is no flux to remove it

Question 6

With ____, surface tension helps hold the metal in place, giving excellent bead contour.

A) mild steel
B) aluminum
C) stainless steel
D) low carbon steel

Question 7

With ____, lack of cleanliness may cause the weld pool to show overheating or poor gas coverage.

A) mild steel
B) aluminum
C) stainless steel
D) low carbon steel

Question 8

Which of the following is a reason to use GTA welding?

A) When the weld appearance is not important
B) When speed is required
C) When fine control of the welding process is not needed
D) When a close-tolerance, high-quality weld is required

Question 9

Which of the following is true of tungsten contamination?

A) Tungsten contamination causes a weak weld and must be cleaned.
B) Tungsten particles will not show up, even if the weld is X-rayed.
C) Tungsten contamination is rare and easily controlled.
D) Tungsten particles in the weld will have no effect on the weld.

Question 10

In GTA welding, the torch may be angled ____ for better visibility.

A) perpendicular to the work
B) 0 to 15 degrees from perpendicular
C) 15 to 30 degrees from perpendicular
D) 30 to 45 degrees from perpendicular

Question 11

Using a ____ arc current setting with ____ travel speeds is important when welding stainless steel.

A) high, slower
B) high, faster
C) low, slower
D) low, faster

Question 12

Oxides on ____ may prevent the molten weld pool from flowing together.

A) mild steel
B) aluminum
C) stainless steel
D) low carbon steel

Question 13

A ____ degree angle or less to the plate surface prevents air from being pulled into the welding zone behind the rod.

A) 15 °
B) 20 °
C) 25 °
D) 30 °

Question 14

Carbon is the primary alloy in the classification of low carbon and mild steel, and ranges from ____ for mild steel.

A) 0.01% to 0.15%
B) 0.10% to 0.15%
C) 0.15% to 0.20%
D) 0.15% to 0.30%

Question 15

With ____, cleanliness is a critical factor.

A) mild steel
B) aluminum
C) stainless steel
D) low carbon steel

Question 16

When might the GTAW process be used to make only the root pass on a pipe weld?

A) When a higher skilled welder to complete the weld is not available
B) When there is a faster process available to complete the weld
C) When it is too windy to do any more welding
D) When it is time to go home

Question 17

What should be done to the end of the filler rod if it becomes oxidized?

A) The end of the rod should be cut off.
B) Melt it off before it is going to be added to the weld pool.
C) Get a new piece of filler metal to restart the weld.
D) Nothing, the oxides are lighter than the weld metal and will float on top of the weld pool.

Question 18

Which of the following is true of welding machine settings?

A) The welding machine range is the same from machine to machine.
B) The setting will be the same for a given thickness of metal from machine to machine.
C) The setting will be the same for a given polarity from machine to machine.
D) The setting will differ for various sizes and types of tungsten from machine to machine.

Question 19

The greater the contamination of a stainless steel weld, the ____ of the bead after the weld.

A) lighter the color
B) redder the color
C) whiter the color
D) darker the color

Question 20

Carbide precipitation is the combining of ____.

A) carbon with chromium
B) carbide with hydrogen
C) carbide with water
D) carbon with oxygen

Question 21

During the manufacturing process, sometimes pockets of primarily ____________________ gas become trapped inside low carbon and mild steels.

Question 22

What are the Experiments in this chapter designed to do?

A) Help new welders learn basic skills that will help them troubleshoot welding problems.
B) Keep new students busy in the welding shop on the first few days.
C) Have the student use up the scrap metal and filler rods while they are just learning to weld.
D) Demonstrate that GTA welding can be fun.

Question 23

A thick piece of metal that is used to absorb heat is also called a(n) ____________________.

Question 24

Explain why a few molecules of gas trapped inside microscopic pockets within the steel can cause porosity in GTA welding, but not in other types of welding.

Question 25

Explain how a new student may clean a practice weld of tungsten contamination.

Question 26

Why would a welder stick the end of the filler rod in the weld pool as the weld is being stopped?

A) It accidentally happens sometimes but they would not do it on purpose.
B) To prevent dropping it when changing positions
C) To help to prevent crater cracking
D) It cools off the end of the filler rod to prevent oxidization.

Question 27

When tungsten touches the molten weld pool, ____________________ pulls the contamination up onto the hot tungsten.

Question 28

When setting up to make a GTA weld on low carbon steel, the tungsten should be ________ and the welding machine set for____________.

A) rounded, AC
B) pointed, DCEN
C) set 1 in. (25 mm) out of the nozzle, DCEN
D) even with the nozzle, DCEP

Question 29

Failure to remove tungsten contamination properly will result in ____________________.

Question 30

Most GTA filler metals have some alloys, called ____________________, that can help prevent porosity caused by gases trapped in the base metal.

Question 31

Under what conditions is the amperage set on a machine equal to the actual welding current?

Question 32

Explain why the filler rod end must be kept inside the protective zone.

Question 33

Mild steel weld coupons can have the welds removed using an OFC torch, but welds on stainless and aluminum coupons will have to be cut out with a(n) ____________________ torch.

Question 34

___________________ is GTA welded using a rounded tip tungsten, with the welding machine set for ACHF welding current.

Question 35

As the gas flows out of the torch it must form a(n) ____________________ around the weld.

Question 36

What can cause porosity (tiny bubbles) to form on some welds on mild steel?

A) A chemical reaction between the filler metal and the mild steel
B) Using the wrong type of tungsten electrode
C) Small pockets of CO₂trapped inside of the steel during manufacturing
D) Too much heat and the metal begins to boil

Question 37

The torch may be angled for better visibility, and still have the proper shielding ____________________.

Question 38

With stainless steel, it is desirable to take the time and necessary precautions to make welds that are no darker than the color ____________________.

Question 39

Why would a welder need to make a list of machine settings?

A) To study for an exam
B) To make it easier to reset the machine for different setups that might be needed
C) To demonstrate to their classmates that they know how to make the correct settings
D) To bring in the classroom for a test

Question 40

Describe how the velocity of the shielding gas and the torch angle affects the protective zone.