AWS Welding Inspection and Testing Certification Practice Test

A groove that is melted into the base metal adjacent to the toe of the weld and left unfilled is called?

1. Stress cracking

2. Cold lap

3. Undercut

4. Underfill

The correct answer is: Undercut

The type of groove that is melted into the base metal adjacent to the toe of the weld and is left unfilled is referred to as an undercut. This defect can occur during the welding process when the heat input is too high or the welding speed is too fast, leading to a shallow groove in the base metal surrounding the welded area. Undercut is significant because it weakens the joint by reducing the effective cross-sectional area and can potentially lead to premature failure of the weld under applied loads. Therefore, recognizing and preventing undercut is critical in ensuring the integrity and strength of the welded structure. Other terms presented, such as stress cracking, cold lap, and underfill, describe different issues in welding. Stress cracking pertains to cracks that develop because of residual stresses in the weldment, cold lap is related to inadequate fusion between weld layers or between the weld and base metal, and underfill describes a condition where the weld metal does not fill the joint completely but does not create a groove in the base metal. Each of these terms has distinct implications in welding quality and inspection, but the term best fitting the description in the question is undercut.