Why are low-alloy steels typically chosen for intake valves?

Low-alloy steels are commonly selected for intake valves due to their ability to withstand the corrosive effects of hot exhaust gases. The demanding conditions in which intake valves operate—exposed to high temperatures and combustion byproducts—require materials that can maintain their integrity and functionality over time. Low-alloy steels are specifically engineered to enhance certain properties, including resistance to wear and corrosion, making them an ideal choice for components that will face harsh environments.

While the other options touch upon certain beneficial traits, they do not specifically address the unique challenges presented to intake valves. Factors like weight, cost, and tensile strength may play a role in the selection of materials for different components, but it is the corrosion resistance in the face of hot exhaust gases that is paramount for the long-term reliability and performance of intake valves, thereby solidifying the choice of low-alloy steels for this application.