Cast tool alloys characterized by high high-temperature strength and extreme wear resistance rely primarily on which principal alloying elements?
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Answer: A. Cobalt, chromium & tungsten
Explanation
Stellite and similar cast tool alloys derive their red hardness from cobalt, chromium, and tungsten. Cobalt provides a tough matrix while chromium and tungsten form hard carbides for extreme wear resistance. This specific elemental combination allows cutting tools to maintain hardness at elevated operating temperatures. Cast tool alloys retain their cutting edge strength at high temperatures where conventional steels soften. Tungsten and chromium form complex carbides dispersed throughout the cobalt-rich alloy matrix. These materials bridge the performance gap between high-speed steels and hard ceramic cutting tools.
Machining hard materials at high cutting speeds requires tool alloys with exceptional hot hardness. Valve seats in heavy-duty internal combustion engines use cobalt-based cast alloys to resist wear. Tooling engineers select alloy compositions carefully to maximize service life in abrasive machining environments. Cobalt, chromium, and nickel alloys form superalloys, but tungsten is essential for cast tool alloy wear resistance. Molybdenum, tungsten, and chromium are primary alloying elements in high-speed steels rather than cast Stellite alloys. Zirconium is used in specialized ceramics and cladding but not as a principal element in traditional cast tool alloys.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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