What percentage range of carbon is typically found in raw pig iron___________________?
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Answer: D. 4 to 4.5%
Explanation
Raw pig iron is the primary crude metal produced by smelting iron ore with coke and limestone inside a blast furnace. The molten iron absorbs large amounts of carbon from the burning coke during the reduction process in the furnace stack. Chemical analysis of raw pig iron consistently reveals a high carbon concentration ranging between four and four point five percent. Pig iron is extremely hard and brittle due to its high carbon content, making it unsuitable for direct structural applications. Subsequent steelmaking processes use basic oxygen furnaces or electric arc furnaces to burn off excess carbon from pig iron. Foundries remelt pig iron with scrap metal in cupola furnaces to produce various grades of grey and ductile cast iron.
Option A and B represent carbon ranges typical of steels rather than raw, unrefined blast furnace pig iron. Option C of two point five to four percent describes cast iron compositions after some carbon has been controlled or removed. Option E of four point five to six point three percent exceeds the normal solubility limits achieved in standard blast furnace operations.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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