What is the usual carbon percentage range in grey cast iron castings __________________?
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Answer: C. 2.5 to 4.5%
Explanation
Grey cast iron typically contains carbon in the range of 2.5 percent to 4.5 percent. Most of this carbon is present as graphite flakes embedded within the metallic matrix. This high carbon composition gives grey cast iron its characteristic dark fracture appearance and properties. Carbon is the primary alloying element that dictates the mechanical behavior of cast iron materials. When iron-carbon melts cool slowly, excess carbon precipitates out as graphite rather than forming cementite. The graphite flakes act as internal stress concentrators, providing excellent machinability and damping capacity.
Engine blocks, machine tool bases, and heavy-duty pipes frequently utilize grey cast iron castings. Engineers select this material because it effectively absorbs vibrational energy and resists wear during operation. Understanding carbon limits ensures manufacturers produce castings without excessive brittleness or structural failure. Lower carbon percentages between 0.5 and 2 percent are typical for various types of steel. Percentages above 5 percent exceed the practical solubility limits for standard engineering grey iron compositions. Option A and option B describe carbon ranges more suitable for structural steels than cast iron.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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