Magnetic Particle Inspection Level 1 Practice Exam

Which of the following is considered a common casting discontinuity?

1. Cold shuts and hot tears

2. Surface cracks

3. Porosity and inclusions

4. Welding defects

The correct answer is: Cold shuts and hot tears

Cold shuts and hot tears are indeed common casting discontinuities. Cold shuts occur when two streams of molten metal meet but do not fuse properly, leading to a defect on the surface of the casting. This often happens when the metal cools too quickly before the two streams have fully combined. Hot tears, on the other hand, are cracks that form in the metal as it cools and solidifies, often due to internal stresses. Both of these defects specifically arise during the casting process, making them typical examples of discontinuities found in cast parts. While the other options, such as surface cracks, porosity, inclusions, and welding defects, do represent various types of material defects, they are not exclusive to the casting process. Surface cracks can occur in various manufacturing processes, while porosity and inclusions can be found in both cast and wrought materials. Welding defects are related to the welding process, which is separate from casting. Thus, cold shuts and hot tears are more accurately described as specific casting discontinuities.