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Q & A: Iron, Steel, and Rust

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Most recent answer: 10/22/2007
Q:
What is rust and what is the difference between iron and steel
- Deborah Kisiel (age 11)
Kanaka Creek Elementary School, Maple Ridge, B.C., Canada,
A:
Iron is a pure element. Every atom in a chunk of iron is an iron atom. Iron is nice, but it's not very strong.

Steel is even better. To make steel, they melt down iron and mix in small amounts of other elements. There are different types of steel based on what they mix in and how much. Each type of steel has different advantages, such as stength, durability, chemical reactivity, and many other qualities. Typical elements that are added to iron to make steel include Carbon, Manganese, Silicon, Chromium, and Molybdenum. But most of the atoms of steel are still iron, because they only usually add in a few percent of other elements.

Now comes rust. Many elements like to go through chemical reactions with other elements. Iron likes to react with oxygen to for iron-oxide...or rust. We can't keep oxygen away from the iron in our cars since much of the atmosphere is oxygen. Rust weakens the iron and can make parts break. Steel has the same problem, but some of those elements that are added during the steel production can help prevent rust or at least slow it down. For example, "stainless steel" is designed so that it will not rust, but it is more expensive that other types of steel.


Adam

(published on 10/22/2007)

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