Visual Testing (VT) Practice Exam

During the visual examination of an arc strike, what should the inspector look for?

1. Lack of fusion

2. Craters

3. Whiskers

4. Cracks

The correct answer is: Cracks

When inspecting an arc strike, looking for cracks is crucial because these defects can significantly compromise the integrity of the material. Arc strikes occur when an electric arc creates intense heat that can alter the microstructure of the affected area, potentially leading to stress concentrations and resulting in cracks during subsequent loading or thermal cycles. Inspectors must examine the heat-affected zone for visible cracks or fissures as they may indicate underlying issues that could lead to failure if not addressed. While other defects like lack of fusion, craters, or whiskers can be relevant in various contexts, they are not the primary concerns during an arc strike inspection. Cracks specifically signal a direct consequence of the high temperatures associated with an arc strike and are an important indicator of the health and safety of the welded joint or component. Therefore, identifying cracks is critical for ensuring the material's durability and performance.