What approximate surface hardness range is achievable through the nitriding process__________________?
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Answer: C. 1000 to 1100 VPN
Explanation
Nitriding is a thermochemical surface hardening process that diffuses nitrogen into steel components. This diffusion creates hard metal nitrides that achieve hardness values between 1000 and 1100 VPN. Such high surface hardness provides exceptional wear resistance without needing quenching heat treatments. VPN stands for Vickers Pyramid Number, a standard scale used to measure micro-indentation hardness. Nitriding operates at relatively low temperatures, minimizing thermal distortion in precision machined parts. Alloying elements like aluminum, chromium, and molybdenum form stable nitrides during the process.
Crankshafts, gear teeth, and extrusion screws are routinely nitrided to withstand abrasive industrial wear. Engine components treated this way exhibit longer service lives and improved fatigue strength characteristics. Automotive manufacturers rely on nitriding to harden steel parts without risking quench cracking or warping. Option A represents a lower hardness level typically achieved by conventional carburizing or induction hardening. Option B describes extreme hardness values exceeding standard nitriding limits for typical engineering steels. Option D represents mild steel surface hardness prior to undergoing any thermal or thermochemical treatment.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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