AWS Certified Welding Inspector — FundamentalsWelding MetallurgyMedium
A metallurgist is designing an alloy for a high-temperature application where resistance to deformation under prolonged stress is critical. Which of the following alloying elements is most effective in improving the creep resistance of steel?
- AManganese
- BPhosphorus
- CSulfur
- DMolybdenum
Show answer & explanationAnswer & explanation
Correct answer: D. Molybdenum
Molybdenum is a highly effective alloying element for improving the creep resistance of steel, particularly at elevated temperatures, by forming stable carbides and strengthening the matrix.
Why the other options are wrong
- A. Manganese is primarily used as a deoxidizer and to improve hardenability and strength, but its direct contribution to creep resistance is less significant than molybdenum's.
- B. Phosphorus is typically an impurity that can cause embrittlement and does not contribute to creep resistance.
- C. Sulfur is generally considered an impurity that forms low-melting sulfides, reducing toughness and hot ductility, and does not improve creep resistance.
Creep Resistance
The ability of a material to resist permanent deformation under prolonged stress at elevated temperatures.
- Critical for high-temperature applications
- Influenced by alloying elements
- Related to microstructural stability
- Temperature and stress are key factors
Memory trick: Mo makes it strong, even when it's hot for long.