AWS Troubleshooting & Diagnostics 3

Question 1

Porosity is found throughout a GMAW weld on galvanized steel. What is the primary cause?

Accepted Answer

Zinc vapor from the coating contaminating the weld pool

Answer

Galvanized steel releases zinc vapors during welding that become trapped in the solidifying weld pool, causing porosity.

Question 2

A welder experiences arc blow when using SMAW with DC current. Which is the most effective remedy?

Accepted Answer

Switch to AC current

Answer

Arc blow is caused by magnetic fields associated with DC current; switching to AC eliminates the directional magnetic force that causes arc deflection.

Question 3

Crater cracks appear at the end of a weld pass. What is the most effective prevention technique?

Accepted Answer

Use a run-off tab or backfill the crater before extinguishing the arc

Answer

Using a run-off tab or backfilling the crater ensures the shrinkage void is filled before the weld metal solidifies, preventing crater cracks.

Question 4

During SMAW in the vertical-up position, the welder notices the weld metal sagging. What adjustment should be made?

Accepted Answer

Reduce amperage and use a weaving technique

Answer

Reducing amperage lowers heat input so the weld pool is less fluid, and a weaving technique allows the metal to partially solidify before depositing more.

Question 5

A weld joint shows incomplete joint penetration (IJP) on a butt weld. Which factor is least likely to be the cause?

Accepted Answer

Shielding gas mixture containing argon

Answer

Argon-containing shielding gas is used routinely in GMAW and is not a cause of incomplete joint penetration; root gap, amperage, and travel speed all directly affect penetration.

AWS Practice Test

AWS Practice Test

AWS Troubleshooting & Diagnostics 3