Fundamentals Flashcards

Which welding process uses a non-consumable tungsten electrode and a separate filler metal?

Answer: GTAW

GTAW (Gas Tungsten Arc Welding) uses a non-consumable tungsten electrode; filler metal is added separately if needed.

What does the term 'heat-affected zone' (HAZ) refer to in welding?

Answer: The base metal area altered by heat but not melted

The HAZ is the portion of the base metal whose properties have been altered by welding heat without actually melting.

A CWI discovers a crack running along the centerline of a weld bead. This defect is most likely caused by:

Answer: High sulfur or phosphorus content in the base metal

Centerline (hot) cracking is commonly caused by low-melting-point impurities such as sulfur and phosphorus segregating at the weld centerline.

According to AWS D1.1, what is the minimum preheat temperature for welding 1-inch thick ASTM A36 steel when the ambient temperature is above 32°F?

Answer: No preheat required

AWS D1.1 Table 4.5 requires no minimum preheat for A36 steel up to 1.5 inches thick when temperature is above 32°F.

Which discontinuity is characterized by fusion that does not extend to the full cross-section of the joint as specified?

Answer: Incomplete joint penetration

Incomplete joint penetration occurs when the weld metal fails to extend through the full thickness specified in the design.

What is the purpose of a preheat when welding high-carbon or alloy steels?

Answer: Reduce the risk of hydrogen-induced cracking

Preheat slows the cooling rate of the HAZ, allowing hydrogen to diffuse out and reducing the risk of cold (hydrogen-induced) cracking.

When visually inspecting a completed groove weld, the inspector should verify the weld face reinforcement does NOT exceed:

Answer: The limit specified in the applicable code or standard

Acceptable reinforcement limits vary by code; the inspector must always apply the limit stated in the governing code or engineering document.