Red Seal Metal Fabricator (Fitter) Practice Exam

Which of the following is a common defect related to welding?

1. Undercut

2. Corrosion

3. Fatigue

4. Oxidation

The correct answer is: Undercut

The selection of undercut as a common defect related to welding is quite accurate. Undercut occurs when the base metal is not melted adequately during the welding process, which leads to a groove or notch at the edge of the weld. This defect can compromise the strength and integrity of the weld joint, making it less capable of bearing load or resisting failure. The occurrence of undercut is often due to issues such as improper welding technique, incorrect settings on welding equipment, or inappropriate filler metal selection. In contrast, while corrosion, fatigue, and oxidation are significant in their own contexts, they are not categorized specifically as welding defects. Corrosion refers to the chemical or electrochemical deterioration of a material, typically metal, which happens over time due to environmental factors. Fatigue describes the progressive structural damage that occurs when a material is subjected to cyclic loading, which is not exclusive to the welding process. Oxidation involves the reaction of metal with oxygen, often leading to rust or degradation, but it is more a chemical reaction than a direct defect arising from the welding process itself. Therefore, undercut is distinctly recognized as a defect that directly results from the welding operation.