AWS Gas Tungsten Arc Welding (GTAW/TIG) Fundamentals

Question 1

What type of tungsten electrode is recommended for welding aluminum with GTAW using AC power?

Accepted Answer

Pure tungsten (green band) or zirconiated tungsten (white band)

Answer

2% Thoriated (red band) tungsten

Answer

2% Ceriated (gray band) tungsten

Answer

Lanthanated (gold band) tungsten

Question 2

The primary advantage of GTAW over SMAW for welding thin stainless steel is:

Accepted Answer

Precise heat control, no slag, and superior weld quality with no contamination

Answer

Higher deposition rate

Answer

Lower equipment cost

Answer

Faster travel speed

Question 3

In GTAW, 'high-frequency (HF) arc initiation' is used to:

Accepted Answer

Initiate the arc without contact between the tungsten and base metal, preventing tungsten contamination

Answer

Increase travel speed by pre-ionizing the arc path

Answer

Preheat the base metal before welding

Answer

Increase penetration on thick sections

Question 4

What is the purpose of post-flow (post-purge) in GTAW?

Accepted Answer

Continue shielding gas flow after arc extinguishment to protect the hot tungsten and weld pool from oxidation

Answer

Cool the tungsten slowly to prevent cracking

Answer

Purge the hoses before the next weld

Answer

Reduce gas consumption by gradually decreasing flow

Question 5

The correct tungsten electrode preparation for GTAW DCEN (direct current electrode negative) on carbon steel is:

Accepted Answer

Ground to a sharp point or taper

Answer

Balled tip

Answer

Blunt flat end

Answer

Random preparation — shape doesn't matter

Question 6

Back purging in GTAW of stainless steel tubing is performed to:

Accepted Answer

Prevent oxidation ('sugaring') on the back side of the root pass

Answer

Increase arc energy by filling the tube with argon

Answer

Reduce the amount of filler metal needed

Answer

Allow faster travel speeds