Welding Fundamentals Flashcards

What is the primary purpose of preheating base metal before welding?

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.

In GTAW (TIG welding), what is the purpose of high-frequency (HF) arc start?

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.

Which symbol on a welding drawing indicates the weld is to be made all around the joint?

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.

What is the correct action when low-hydrogen electrodes (E7018) have been exposed to humidity?

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.

What does PWHT (Post-Weld Heat Treatment) primarily accomplish?

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.

In a welding symbol, where is the weld specification placed when the weld is required on the arrow side of the joint?

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.

Which welding process uses a continuously fed consumable wire electrode and a blanket of granular flux?

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.