AWS Weld Discontinuities & Defects 2

Question 1

Hot cracking in welds is most likely to occur when:

Accepted Answer

High-sulfur or high-phosphorus impurities are present in the weld metal

Answer

Hot cracking (solidification cracking) is promoted by impurities such as sulfur and phosphorus, which form low-melting eutectic films at grain boundaries that crack under solidification stresses.

Question 2

Which condition is the most common cause of porosity when using the Shielded Metal Arc Welding (SMAW) process?

Accepted Answer

Moisture in the electrode coating or base metal

Answer

Moisture in SMAW electrode coatings or on the base metal decomposes in the arc to produce hydrogen, which is absorbed into the weld pool and causes porosity upon solidification.

Question 3

Lamellar tearing in welded joints occurs primarily in which orientation?

Accepted Answer

Parallel to the original rolling plane of the plate

Answer

Lamellar tearing occurs in base metals with low through-thickness ductility, cracking in a step-like pattern parallel to the rolling plane due to high through-thickness shrinkage stresses.

Question 4

Incomplete joint penetration (IJP) is most likely to occur when:

Accepted Answer

The root opening or groove angle is insufficient for the welding process

Answer

IJP occurs when the weld metal fails to extend through the full thickness of the joint, which is commonly caused by an inadequate root opening or groove angle that limits access for fusion.

Question 5

To reduce undercut when welding, the welder should primarily:

Accepted Answer

Reduce welding current and slow travel speed at the weld toes

Answer

Reducing the welding current and slowing travel speed at the weld toes allows the weld pool to fill the undercut groove, and a slight weave pause at the toe ensures proper tie-in.

AWS Practice Test

AWS Practice Test

AWS Weld Discontinuities & Defects 2