API 571 Certification (Corrosion & Materials) Practice Test

What type of materials does caviation primarily affect in construction?

1. Carbon fibers

2. Low-alloy steels

3. Cast iron and stainless steels

4. PVC and composite materials

The correct answer is: Cast iron and stainless steels

Cavitation primarily affects materials such as cast iron and stainless steels due to the conditions under which cavitation occurs. In processes where rapid changes in pressure cause the formation and collapse of vapor bubbles in a liquid, such as in pumps and propellers, the intense localized pressure and temperature created during bubble collapse can lead to erosion and damage to the surfaces of these materials. Cast iron is particularly vulnerable because, while it has high compressive strength, it can be brittle and may suffer from surface damage when subjected to the impact of collapsing vapor bubbles. Stainless steels, especially those used in high-performance applications, must be carefully selected to withstand the corrosive and erosive effects of cavitation. The combination of cavitation's mechanism and the properties of these materials makes them the primary targets for such damage in construction environments. Other materials listed, like carbon fibers and PVC, generally do not experience cavitation effects to the same degree because they are not typically used in applications where liquid dynamics and high-pressure systems are involved. Low-alloy steels can resist some forms of damage but may not be as severely impacted by cavitation as the materials indicated in the correct choice.