Difficulty: Easy
Correct Answer: axles and springs
Explanation:
Introduction / Context:
Alloy selection in mechanical design hinges on matching material properties to service demands. Vanadium, when added to steel (often along with chromium and carbon), refines grain size and forms strong carbides, improving strength, fatigue resistance, and tempering stability. This question asks which components most appropriately leverage these benefits in typical engineering practice.
Given Data / Assumptions:
Concept / Approach:
Axles and springs endure repeated bending/torsional cycles and impacts. Vanadium steels (e.g., Chrome–Vanadium grades like 50CrV4) resist fatigue and maintain properties after heat treatment, making them well suited for torsion/bending-loaded parts. Bearing balls are commonly made from high-carbon chromium steel (e.g., AISI 52100). Magnets are special alloys/ceramics (AlNiCo, ferrites, rare earths). Railway switches and crossings generally use manganese steel or heat-treated rails optimized for wear and impact, not specifically vanadium steels as the principal alloying route.
Step-by-Step Solution:
Verification / Alternative check:
Materials handbooks list Cr–V steels for coil/leaf springs, torsion bars, and axle shafts due to superior fatigue strength and temper resistance.
Why Other Options Are Wrong:
Railway switches/crossings — Prefer manganese or pearlitic rail steels for wear impact.
Bearing balls — Typically AISI 52100 high-carbon chromium steel.
Magnets — Not steel-vanadium products; use magnetic alloys or ceramics.
Common Pitfalls:
Assuming any “alloy steel” suits bearings or tracks; overlooking fatigue as the governing design criterion for springs/axles.
Final Answer:
axles and springs
Discussion & Comments