ITMC Welding Fundamentals 3 — Questions and Answers
Question 1: What is the primary purpose of preheating base metal before welding?
- To increase welding speed
- To reduce the risk of hydrogen cracking and thermal shock (Correct answer)
- To eliminate the need for post-weld heat treatment
- To improve shielding gas coverage
Correct answer: To reduce the risk of hydrogen cracking and thermal shock
Preheating slows the cooling rate of the weld, which reduces hydrogen-induced cracking and minimizes residual stresses caused by thermal gradients.
Question 2: In GTAW (TIG welding), what is the purpose of high-frequency (HF) arc start?
- To clean aluminum oxide from the base metal
- To initiate the arc without touching the tungsten to the workpiece (Correct answer)
- To increase penetration depth
- To stabilize the shielding gas flow
Correct answer: To initiate the arc without touching the tungsten to the workpiece
HF arc start allows the GTAW arc to be initiated without contaminating the tungsten electrode by touching the workpiece.
Question 3: Which symbol on a welding drawing indicates the weld is to be made all around the joint?
- A flag symbol on the reference line
- A circle at the junction of the arrow and reference line (Correct answer)
- A filled circle at the tail
- An M above the reference line
Correct answer: A circle at the junction of the arrow and reference line
A circle at the bend of the arrow on a welding symbol indicates that the weld is required all around the joint perimeter.
Question 4: What is the correct action when low-hydrogen electrodes (E7018) have been exposed to humidity?
- Use them immediately while still moist
- Discard them as they cannot be reconditioned
- Re-dry them in a rod oven per manufacturer specifications (Correct answer)
- Store them in an open container to air dry
Correct answer: Re-dry them in a rod oven per manufacturer specifications
Moisture-absorbed low-hydrogen electrodes must be re-dried in a rod oven at the manufacturer's recommended temperature and time to restore their low-hydrogen properties.
Question 5: What does PWHT (Post-Weld Heat Treatment) primarily accomplish?
- Increases weld hardness and strength
- Relieves residual stresses and improves toughness (Correct answer)
- Eliminates all porosity in the weld
- Prepares the weld for painting
Correct answer: Relieves residual stresses and improves toughness
PWHT reduces residual stresses locked in the weld and HAZ during cooling, and can improve toughness and resistance to stress corrosion cracking.
Question 6: In a welding symbol, where is the weld specification placed when the weld is required on the arrow side of the joint?
- Above the reference line
- Below the reference line (Correct answer)
- At the tail of the arrow
- At the left end of the reference line
Correct answer: Below the reference line
Weld symbols placed below the reference line indicate the weld is to be made on the arrow side of the joint.
Question 7: Which welding process uses a continuously fed consumable wire electrode and a blanket of granular flux?
- FCAW (Flux-Cored Arc Welding)
- SAW (Submerged Arc Welding) (Correct answer)
- GMAW (Gas Metal Arc Welding)
- ESW (Electroslag Welding)
Correct answer: SAW (Submerged Arc Welding)
Submerged Arc Welding (SAW) uses a continuously fed wire electrode submerged under a layer of granular flux that shields and refines the weld.
ITMC Welding Fundamentals 3
What is the primary purpose of preheating base metal before welding?