AWS Gas Tungsten Arc Welding (GTAW/TIG) 5

Question 1

In pulsed GTAW, what is the primary advantage of using a high pulse frequency?

Accepted Answer

Improves arc stability and refines the weld microstructure

Answer

High pulse frequency in GTAW improves arc stability, refines grain structure, and reduces distortion, making it beneficial for thin materials and precision welds.

Question 2

What does a 'walking the cup' technique in GTAW involve?

Accepted Answer

Bracing the gas cup against the pipe to guide the torch in a controlled weave

Answer

Walking the cup involves bracing the ceramic cup against the pipe joint and pivoting/rolling it to maintain a consistent arc length and travel angle, commonly used in pipe root passes.

Question 3

When GTAW welding a pipe root pass open to atmosphere on the inside, what process is used to protect the back side of the root from oxidation?

Accepted Answer

Purging with inert gas (back purging)

Answer

Back purging displaces oxygen inside the pipe with inert gas (typically argon) to prevent oxidation of the root pass on the ID of the pipe.

Question 4

What is the effect of using too long an arc length in GTAW?

Accepted Answer

Wider, flatter bead with more oxidation and reduced penetration

Answer

An excessively long arc length diffuses the heat, producing a wide, shallow bead with reduced shielding effectiveness and increased risk of atmospheric contamination.

Question 5

According to AWS standards, what is the maximum acceptable tungsten inclusion size in a radiographically tested weld?

Accepted Answer

They are evaluated per the applicable acceptance criteria in the governing code (e.g., AWS D1.1)

Answer

Tungsten inclusion acceptance criteria depend on the governing welding code or standard being applied, such as AWS D1.1, which specifies size and frequency limits.

AWS Practice Test

AWS Practice Test

AWS Gas Tungsten Arc Welding (GTAW/TIG) 5