The GTAW Process

Question 1

Define the term GTAW

Answer 1

Gas tungsten arc welding
Process in which fusion welding is accomplished by the heat of an electric arc drawn between a non consumable tungsten electrode and the work.

Question 2

With GTAW the heat of the arc is transferred to the work through non consumable

Answer 2

Tungsten electrode

Question 3

GTAW requires an inert gas to

Answer 3

Shield the weld puddle

Question 4

GTAW is used primarily when

Answer 4

High quality welds are mandatory

Question 5

For what application would hot wire GTAW be used

Answer 5

Where high production welds are required

Question 6

State the major difference between hot wire GTAW and cold wire GTAW

Answer 6

Hot wire GTAW has the wire preheated with an auxiliary AC current prior to the wire entering the weld pool, where as the cold wire process feeds wire that is at ambient temp and without an auxiliary power source attached

Question 7

In what positions can the GTAW process be used

Answer 7

All positions

Question 8

Which metal requires a full preheat when welded with the GTAE process

Answer 8

Cast iron

Question 9

GTAW has an advantage over SMAW because it

Answer 9

Can eliminate the need to use a flux

Question 10

The intensity of the ultraviolet light produced by the GTAW process is like ……. Metal arc welding, but is much greater than that produced by the ……. Metal arc welding process

Answer 10

Gas metal arc welding

Shielded metal arc welding

Question 11

When welding with GTAW you should wear

Answer 11

Dark coloured tightly woven clothing

Question 12

When using GTAW good ventilation is required to prevent

Answer 12

An oxygen deficiency

Question 13

The arc radiation from GTAW reacts with elements in atmospheric air to form

Answer 13

O3 (ozone)

Question 14

Ultraviolet radiation from GTAW can react with chlorinated degreasing solvents to produce

Answer 14

Phosgene gas

Question 15

Pulsing the arc with GTAW is an advantage when

Answer 15

Penetration on thin metals must be controlled

Question 16

Welding machines designed for GTAW are

Answer 16

Constant current

Question 17

Which statement is true with respect to orbital GTAW

Answer 17

It can be done without filler wires

Question 18

Which of the following machines would be best suited for GTAW

Answer 18

AC/DC rectifier

Question 19

Power sources recommended for GTAW have a …….. volt amp curve

Answer 19

Steep drooping

Question 20

A post purge control is designed to

Answer 20

Keep gas flowing for a pre set time after the arc is extinguished

Question 21

What is the recommended size of electrode when using 125 amps on
AC current
DCEN
DCEP

Answer 21

AC 3/32

DCEN 1/16

DCEP 1/4

Question 22

What is the recommended current type for welding stainless steel

Answer 22

DCEN

Question 23

Which current type produces the deepest penetration

Answer 23

DCEN

Question 24

Removal of aluminum oxide occurs

Answer 24

During the positive half of the AC cycle

Question 25

AC high frequency is most suited for GTAW on

Answer 25

Aluminum and magnesium

Question 26

Continuous high frequency current is required when

Answer 26

A stabilized AC current is required

Question 27

Which statement is true with respect to square waves

Answer 27

The EP and EN portions can be adjusted

Question 28

Why should the torch cables be kept as short as possible when using GTAW

Answer 28

To help prevent the loss of high frequency current as it travels from the machine to the electrode

Question 29

A GTAW torch that is too small for the current setting overheats the …

Answer 29

A GTAW torch that is too small for the current used overheats the torch body

Question 30

A torch cap is the part of a GTAW torch that

Answer 30

Protects the electrode from accidental arc strikes

Question 31

A collet is a device in the GTAW torch that

Answer 31

Positions the electrode and transfers current

Question 32

The diameter of the nozzle is normally determined by

Answer 32

The size of the puddle and electrode

Question 33

To use continuous high frequency the nozzle must be constructed of

Answer 33

Ceramic

Question 34

What is the purpose of a regulator when used with GTAW

Answer 34

To reduce supply pressure to a safe working pressure

Question 35

A flow meter is calibrated in

Answer 35

Litres per min or cubic feet per hr

Question 36

What is the purpose of a flow meter when used with GTAW

Answer 36

To meter the flow of shielding gas

Question 37

A floating ball type flow meter must be used in the ….. position

Answer 37

Vertical

Question 38

What type of hose is recommended when using helium shielding gas

Answer 38

Plastic

Question 39

What’s are the advantages of using orbital GTAW

Answer 39

Increase productivity Superior weld quality and consistency Certified welder sets parameters someone else can operate it Maybe only solution where pipe cannot be rolled Well suited for applications where physical access is limited