Identify the trade name of the cobalt–chromium–tungsten non-ferrous cast alloy widely used for wear-resistant cutting edges and hot-hard applications.
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Aceramic
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Bstellite
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Cdiamond
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Dcemented carbide
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Ecermet
Answer
Correct Answer: stellite
Explanation
Introduction / Context:Tool and wear-resistant materials are chosen for hot hardness, chemical stability, and toughness. Cobalt–chromium–tungsten cast alloys became famous under a specific trade name for high-temperature and abrasion resistance in valves, dies, and some cutting applications.
Given Data / Assumptions:
- Non-ferrous, cast alloy system containing Co–Cr–W.
- Application focus: wear resistance and hot hardness.
- Recognition of common tooling trade names.
Concept / Approach:Stellite is a family of cobalt-base alloys with chromium and tungsten (often carbon as well), known for excellent hardness at elevated temperature and corrosion resistance. It is not the same as cemented carbides (WC-Co) nor ceramics/cermets, and “diamond” is a superabrasive, not a metallic cast alloy.
Step-by-Step Solution:
Match composition Co–Cr–W → associated with Stellite family.Exclude ceramics/diamond (nonmetallic or superabrasive) and cemented carbide (WC particles in Co binder).Therefore, the trade name is Stellite.Verification / Alternative check:Materials handbooks list Stellite grades (e.g., Stellite 6) with characteristic properties and cast/weld overlay applications.
Why Other Options Are Wrong:
- Ceramic/diamond: not metallic cast alloys of Co–Cr–W.
- Cemented carbide: composite of tungsten carbide grains in cobalt, not a Co–Cr–W cast alloy.
- Cermet: ceramic–metal composite, different class.
Common Pitfalls:Confusing Stellite with tungsten carbide because both involve cobalt; their chemistry, microstructure, and processing differ significantly.
Final Answer:stellite