Troubleshooting & Diagnostics Flashcards
7 cards from real AWS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Troubleshooting & Diagnostics flashcards as text
A welder performing GMAW on aluminum notices the weld bead is black and sooty. What is the most likely cause?
Answer: Contamination from oil, oxide, or moisture on the base metal or filler wire
Black, sooty deposits on aluminum GMAW welds indicate contamination from hydrocarbons, oxide, or moisture on the work or filler wire.
During SMAW, a welder notices the arc extinguishes immediately after striking. The most likely cause is:
Answer: Open-circuit voltage (OCV) too low or machine malfunction
If the OCV is insufficient or the welding machine is malfunctioning, there is not enough voltage to sustain the arc after initial striking.
Laminar tearing is found in a thick plate T-joint after welding. Which base metal property contributes most to this defect?
Answer: Low through-thickness ductility (lamellar inclusions parallel to the surface)
Lamellar tearing occurs in steel with low through-thickness ductility due to elongated sulfide or silicate inclusions that allow tearing under through-thickness shrinkage stress.
A welder using GTAW on carbon steel accidentally touches the filler rod to the tungsten. Which action should be taken first?
Answer: Stop, remove and re-prepare the tungsten electrode
Tungsten contaminated by filler metal must be removed and re-prepared (ground or replaced) to restore arc stability and prevent inclusions in the weld.
Visual inspection of a weld reveals a crack that runs along the centerline of the weld bead. This is most likely:
Answer: Centerline hot crack due to low melting point segregants
Centerline cracks are a form of hot cracking caused by low melting point segregants (sulfur, phosphorus) that concentrate at the weld centerline during solidification.
During GMAW, the wire burns back and fuses to the contact tip. What is the most likely cause?
Answer: Wire feed speed too low relative to voltage
When wire feed speed is too low relative to voltage, the arc burns back toward the gun and the wire fuses to the contact tip.
A welder discovers a weld has excessive convexity (high crown) on a fillet weld. Which corrective measure is most appropriate?
Answer: Increase amperage or voltage to flatten the bead
Increasing amperage or voltage provides more heat to spread and flatten the weld bead, reducing excessive convexity.