The alloy known as 'stellite' is used to treat valve interiors to increase hardness and erosion resistance. Which elements comprise this alloy?

The alloy known as 'stellite' is used to treat valve interiors to increase hardness and erosion resistance. Which elements comprise this alloy?

• A. Stainless Steel
• B. Stellite
• C. Chromium Iron
• D. Nickel Alloy

Answer: (B)

Stellite is a family of wear‑resistant, hardfacing alloys used to coat valve interiors. It’s not a single element; it’s a cobalt-based alloy system designed to be hard and erosion resistant. The strength comes from carbide-forming elements added to a cobalt base—primarily chromium and carbon, which form hard carbides at the surface, with other elements like tungsten or vanadium sometimes included to tailor hardness and wear resistance. Because the question is asking which alloy is used for this purpose, the correct choice is the alloy name itself: stellite. The other options describe broader metal families and don’t capture the specific cobalt-based carbide-forming alloy used for this application.

Stellite is a family of wear‑resistant, hardfacing alloys used to coat valve interiors. It’s not a single element; it’s a cobalt-based alloy system designed to be hard and erosion resistant. The strength comes from carbide-forming elements added to a cobalt base—primarily chromium and carbon, which form hard carbides at the surface, with other elements like tungsten or vanadium sometimes included to tailor hardness and wear resistance. Because the question is asking which alloy is used for this purpose, the correct choice is the alloy name itself: stellite. The other options describe broader metal families and don’t capture the specific cobalt-based carbide-forming alloy used for this application.