Why call Carbon steel as "plain" steel?

Please explain its etymology


Best answer:
Answer by tinkertailorcandlestickmaker
Steel is by definition an alloy of iron and carbon, and if it has no significant amounts of any other allowing materials it is "plain" (Adjective: simple or ordinary in character).
If it does have significant other elements in it, it is called alloy steel (or various other names depending on the alloy and use, e.g. "tool steel" "stainless steel" etc)


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