The GTAW Process Flashcards
Define the term GTAW
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.
With GTAW the heat of the arc is transferred to the work through non consumable
Tungsten electrode
GTAW requires an inert gas to
Shield the weld puddle
GTAW is used primarily when
High quality welds are mandatory
For what application would hot wire GTAW be used
Where high production welds are required
State the major difference between hot wire GTAW and cold wire GTAW
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
In what positions can the GTAW process be used
All positions
Which metal requires a full preheat when welded with the GTAE process
Cast iron
GTAW has an advantage over SMAW because it
Can eliminate the need to use a flux
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
Gas metal arc welding
Shielded metal arc welding
When welding with GTAW you should wear
Dark coloured tightly woven clothing
When using GTAW good ventilation is required to prevent
An oxygen deficiency
The arc radiation from GTAW reacts with elements in atmospheric air to form
O3 (ozone)
Ultraviolet radiation from GTAW can react with chlorinated degreasing solvents to produce
Phosgene gas
Pulsing the arc with GTAW is an advantage when
Penetration on thin metals must be controlled
Welding machines designed for GTAW are
Constant current
Which statement is true with respect to orbital GTAW
It can be done without filler wires
Which of the following machines would be best suited for GTAW
AC/DC rectifier
Power sources recommended for GTAW have a …….. volt amp curve
Steep drooping
A post purge control is designed to
Keep gas flowing for a pre set time after the arc is extinguished
What is the recommended size of electrode when using 125 amps on
AC current
DCEN
DCEP
AC 3/32
DCEN 1/16
DCEP 1/4
What is the recommended current type for welding stainless steel
DCEN
Which current type produces the deepest penetration
DCEN
Removal of aluminum oxide occurs
During the positive half of the AC cycle
AC high frequency is most suited for GTAW on
Aluminum and magnesium
Continuous high frequency current is required when
A stabilized AC current is required
Which statement is true with respect to square waves
The EP and EN portions can be adjusted
Why should the torch cables be kept as short as possible when using GTAW
To help prevent the loss of high frequency current as it travels from the machine to the electrode
A GTAW torch that is too small for the current setting overheats the …
A GTAW torch that is too small for the current used overheats the torch body
A torch cap is the part of a GTAW torch that
Protects the electrode from accidental arc strikes
A collet is a device in the GTAW torch that
Positions the electrode and transfers current
The diameter of the nozzle is normally determined by
The size of the puddle and electrode
To use continuous high frequency the nozzle must be constructed of
Ceramic
What is the purpose of a regulator when used with GTAW
To reduce supply pressure to a safe working pressure
A flow meter is calibrated in
Litres per min or cubic feet per hr
What is the purpose of a flow meter when used with GTAW
To meter the flow of shielding gas
A floating ball type flow meter must be used in the ….. position
Vertical
What type of hose is recommended when using helium shielding gas
Plastic
What’s are the advantages of using orbital GTAW
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
