Magnetic Particle Inspection Level 1 Practice Exam

Which discontinuities are classified as inservice discontinuities?

1. Swelling and cracks from forging

2. Fatigue cracking and corrosion

3. Ingot cracks and blowholes

4. Lap and fold defects

The correct answer is: Fatigue cracking and corrosion

Inservice discontinuities refer to flaws that develop in materials or components during their operational life, as a result of conditions such as stress, environmental factors, or material degradation. Fatigue cracking and corrosion are prime examples of inservice discontinuities because both are associated with the wear and tear that occurs as a product is used over time. Specifically, fatigue cracking arises from cyclic loading and repeated stress on materials, leading to the gradual formation of cracks. Corrosion, on the other hand, often results from chemical reactions that degrade materials over time, such as exposure to moisture, chemicals, or environmental pollutants. Both of these phenomena can significantly impact the integrity and performance of components while they are in service, making them critical considerations in the field of magnetic particle inspection. The other options presented do not align with the definition of inservice discontinuities. Swelling and cracks from forging typically occur during the manufacturing process, making them fabrication-related discontinuities rather than inservice issues. Ingot cracks and blowholes are also defects associated with the casting process and thus fall under manufacturing defects or discontinuities. Lap and fold defects are common in welded joints and are related to poor joining techniques during manufacturing rather than conditions experienced in service.