Question 1

​Tungsten electrodes that contain elements such as lanthanum or yttrium are referred to as _____.

Accepted Answer

A)  ​alternating current only electrodes 
B)  ​low-hydrogen tungstens 
C)  ​low-alloy tungsten electrodes 
D)  ​rare earth tungstens 
A)  ​alternating current only electrodes 
B)  ​low-hydrogen tungstens 
C)  ​low-alloy tungsten electrodes 
D)  ​rare earth tungstens D

Question 2

Argon and helium are _________________________ gases, which means they will not combine chemically with any other material, and will not affect the molten weld pool in any way.

Accepted Answer

noble inert
noble
inert

Question 3

Explain how tungsten electrodes are produced.

Accepted Answer

Tungsten is produced mainly by reduction of its trioxide with hydrogen.Powdered tungsten is then purified to 99.95%, compressed, and sintered (heated to a temperature below melting where grain growth can occur) to make an ingot.The ingot is heated to increase ductility and then is swaged and drawn through dies to produce electrodes.These electrodes are available in sizes varying from .01 in.to .25 in.(0.25 mm to 6 mm) in diameter.The tungsten electrode, after drawing, has a heavy black oxide that is later chemically cleaned or ground off.

Question 4

​Which nozzle material is clear?

Accepted Answer

A)  ​ceramic 
B)  ​alumina 
C)  ​fused quartz 
D)  ​silicon nitride 
A)  ​ceramic 
B)  ​alumina 
C)  ​fused quartz 
D)  ​silicon nitride

Question 5

Which of the following is a way to minimize erosion of the tungsten electrode?

Accepted Answer

A)  Using DCEN current. 
B)  Using as high a current as possible. 
C)  Using an air-cooled torch. 
D)  Using as small a size of tungsten electrode as possible. 
A)  Using DCEN current. 
B)  Using as high a current as possible. 
C)  Using an air-cooled torch. 
D)  Using as small a size of tungsten electrode as possible.

Question 6

When the shielding gas flow rate is high, air is drawn into the gas envelope by a(n) ____________________ effect around the edge of the nozzle.

Accepted Answer

The answer of When the shielding gas flow rate is...

Question 7

​What is the purpose of a gas lens?

Accepted Answer

A)  ​It filters out most of the harmful UV and some of the IR light. 
B)  ​It reduces the turbulence in the shielding gas. 
C)  ​It filters out dust and dirt that might be in the shielding gas due to a dirty shielding gas hose. 
D)  ​It helps to see the molten weld pool by magnifying it. 
A)  ​It filters out most of the harmful UV and some of the IR light. 
B)  ​It reduces the turbulence in the shielding gas. 
C)  ​It filters out dust and dirt that might be in the shielding gas due to a dirty shielding gas hose. 
D)  ​It helps to see the molten weld pool by magnifying it.

Question 8

____ additions are restricted to stainless steels because it is the primary cause of porosity in aluminum welds.

Accepted Answer

A)  Nitrogen 
B)  Helium 
C)  Argon 
D)  Hydrogen 
A)  Nitrogen 
B)  Helium 
C)  Argon 
D)  Hydrogen

Question 9

____________________ is the time during which the gas continues flowing after the welding current has stopped.

Accepted Answer

The answer of ____________________ is the time during which the...

Question 10

What is the most likely explanation for why DCEP has a cleaning action?

Accepted Answer

There are many theories as to why DCEP h

Question 11

Which of the following is true of grinding tungsten electrodes?

Accepted Answer

A)  If the grinder is used for metals other than tungsten, particles of these metals may become trapped on the tungsten as it is ground, resulting in contamination when the arc is started. 
B)  A fine, hard grinding stone will result in more tungsten breakage and a poor finish. 
C)  The grinder used to sharpen tungsten should have a coarse stone. 
D)  A grinder should never be used to clean contaminated tungsten. 
A)  If the grinder is used for metals other than tungsten, particles of these metals may become trapped on the tungsten as it is ground, resulting in contamination when the arc is started. 
B)  A fine, hard grinding stone will result in more tungsten breakage and a poor finish. 
C)  The grinder used to sharpen tungsten should have a coarse stone. 
D)  A grinder should never be used to clean contaminated tungsten.

Question 12

Which of the following is true of breaking and remelting tungsten?

Accepted Answer

A)  It should be melted by striking an arc on a piece of carbon. 
B)  It should be broken squarely. 
C)  It should be melted with a DCEN current. 
D)  It should not be melted by striking an arc on copper, as it will contaminate the tungsten. 
A)  It should be melted by striking an arc on a piece of carbon. 
B)  It should be broken squarely. 
C)  It should be melted with a DCEN current. 
D)  It should not be melted by striking an arc on copper, as it will contaminate the tungsten.

Question 13

​Flowmeters measure the flow rate of a shielding gas in __________units.

Accepted Answer

A)  ​BTU or mm/sec 
B)  ​CHF or L/min 
C)  ​PSI or kPa 
D)  ​GPH or K/min 
A)  ​BTU or mm/sec 
B)  ​CHF or L/min 
C)  ​PSI or kPa 
D)  ​GPH or K/min

Question 14

Which of the following is true of erosion of the tungsten electrode?

Accepted Answer

A)  Erosion can be completely eliminated. 
B)  Erosion can be limited using DCEP current. 
C)  The eroded metal does not transfer across the arc. 
D)  Slow erosion results in limited tungsten inclusions in the weld. 
A)  Erosion can be completely eliminated. 
B)  Erosion can be limited using DCEP current. 
C)  The eroded metal does not transfer across the arc. 
D)  Slow erosion results in limited tungsten inclusions in the weld.

Question 15

​What material should shielding gas hoses be made of?

Accepted Answer

A)  ​Any material is fine; the gas is inert 
B)  ​plastic 
C)  ​rubber 
D)  ​copper 
A)  ​Any material is fine; the gas is inert 
B)  ​plastic 
C)  ​rubber 
D)  ​copper

Question 16

Which of the following is an inert gas?

Accepted Answer

A)  Nitrogen 
B)  Oxygen 
C)  Hydrogen 
D)  Helium 
A)  Nitrogen 
B)  Oxygen 
C)  Hydrogen 
D)  Helium

Question 17

The ____ protects the molten weld pool, the filler rod, and the tungsten electrode as they cool to a temperature at which they will not oxidize rapidly.

Accepted Answer

A)  nozzle 
B)  preflow period 
C)  shielding gas 
D)  postflow period 
A)  nozzle 
B)  preflow period 
C)  shielding gas 
D)  postflow period

Question 18

​The useful life of a ceramic nozzle is affected by the _____________.

Accepted Answer

A)  ​tungsten type and shielding gas flow rate 
B)  ​whether the torch is air or water cooled 
C)  ​current level and proximity to the work 
D)  ​type of current and type of base metal 
A)  ​tungsten type and shielding gas flow rate 
B)  ​whether the torch is air or water cooled 
C)  ​current level and proximity to the work 
D)  ​type of current and type of base metal

Question 19

​How must tube- and ball-type flowmeters be mounted?

Accepted Answer

A)  ​vertically 
B)  ​horizontally 
C)  ​on a solid surface 
D)  ​Between 5 ft and 5.5 feet above the floor 
A)  ​vertically 
B)  ​horizontally 
C)  ​on a solid surface 
D)  ​Between 5 ft and 5.5 feet above the floor

Question 20

____ electrodes have a current-carrying capacity similar to that of pure tungsten, and may be used for both AC and DC welding currents.

Accepted Answer

A)  Zirconium tungsten 
B)  Cerium tungsten 
C)  Lanthanum tungsten 
D)  Thoriated tungsten 
A)  Zirconium tungsten 
B)  Cerium tungsten 
C)  Lanthanum tungsten 
D)  Thoriated tungsten

Exam 16: Gas Tungsten Arc Welding Equipment, Setup, Operation, and Filler Metals

​Tungsten electrodes that contain elements such as lanthanum or yttrium are referred to as _____.

Argon and helium are _________________________ gases, which means they will not combine chemically with any other material, and will not affect the molten weld pool in any way.

Explain how tungsten electrodes are produced.

​Which nozzle material is clear?

Which of the following is a way to minimize erosion of the tungsten electrode?

When the shielding gas flow rate is high, air is drawn into the gas envelope by a(n) ____________________ effect around the edge of the nozzle.

​What is the purpose of a gas lens?

____ additions are restricted to stainless steels because it is the primary cause of porosity in aluminum welds.

____________________ is the time during which the gas continues flowing after the welding current has stopped.

What is the most likely explanation for why DCEP has a cleaning action?

Which of the following is true of grinding tungsten electrodes?

Which of the following is true of breaking and remelting tungsten?

​Flowmeters measure the flow rate of a shielding gas in __________units.

Which of the following is true of erosion of the tungsten electrode?

​What material should shielding gas hoses be made of?

Which of the following is an inert gas?

The ____ protects the molten weld pool, the filler rod, and the tungsten electrode as they cool to a temperature at which they will not oxidize rapidly.

​The useful life of a ceramic nozzle is affected by the _____________.

​How must tube- and ball-type flowmeters be mounted?

____ electrodes have a current-carrying capacity similar to that of pure tungsten, and may be used for both AC and DC welding currents.

Introduction to Welding

Safety in Welding

Shielded Metal Arc Equipment, Setup, and Operation

Shielded Metal Arc Welding of Plate

Shielded Metal Arc Welding of Pipe

Shielded Metal Arc Welding Aws Sense Certification

Flame Cutting

Plasma Arc Cutting

Related Cutting Processes

Gas Metal Arc Welding Equipment, Setup, and Operation

Gas Metal Arc Welding

Flux Cored Arc Welding Equipment, Setup, and Operation

Flux Cored Arc Welding

Gas Metal Arc and Flux Cored Arc Welding of Pipe

Gas Metal Arc and Flux Cored Arc Welding Aws Sense Certification

Gas Tungsten Arc Welding of Plate

Gas Tungsten Arc Welding of Pipe

Gas Tungsten Arc Welding Plate and Pipe Aws Sense Certification

Shop Math and Weld Cost

Reading Technical Drawings

Welding Joint Design and Welding Symbols

Fabricating Techniques and Practices

Welding Codes and Standards

Testing and Inspection of Welds

Welding Metallurgy

Weldability of Metals

Filler Metal Selection

Welding Automation and Robotics

Other Welding Processes

Oxyfuel Welding and Cutting Equipment, Setup, and Operation

Oxyacetylene Welding

Brazing, Braze Welding, and Soldering

Filters

Tungsten electrodes that contain elements such as lanthanum or yttrium are referred to as _____.

Which nozzle material is clear?

What is the purpose of a gas lens?

Flowmeters measure the flow rate of a shielding gas in __________units.

What material should shielding gas hoses be made of?

The useful life of a ceramic nozzle is affected by the _____________.

How must tube- and ball-type flowmeters be mounted?