Red Seal Welding Practice Exam

What is the most serious welding defect?

1. Porosity

2. Undercut

3. Cracking

4. Inclusion

The correct answer is: Cracking

Cracking is the most serious welding defect because it can lead to structural failure and compromise the integrity of the welded joint. Porosity, undercut, and inclusion are also common welding defects, but they are not as serious as cracking. Porosity refers to small gas pockets trapped in the weld, while undercut is a groove or notch that forms along the weld edge and can weaken the weld. Inclusion, also known as slag inclusion, occurs when bits of non-metallic material become trapped in the weld and can weaken the joint. While these defects should still be avoided, they are not as detrimental as cracking.