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What Is Stainless Steel

Hi, I was wondering if you would be able to help me with a chemistry assignment? The question at topic is "what is stainless steal made of?, What corrodes it and how to prevent it from corrosion? I hope that you will be able to help me with my assignment and if you would please be able to send it to me as soon as possible.

Thanks a lot for reading this letter of issue.

Brooke Renee A.
Smithfield State High School - Kewarra Beach, QLD, Australia
2004

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First of three simultaneous responses --

Here's a link to some info on stainless steel: http://www.ssina.com/students/how.htm

Bill Duttlinger
- Naperville, Illinois
2004

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Second of three simultaneous responses --

A good old google.com search would turn up a lot of information on stainless steel, but I'll give you a nutshell version. Steel is an alloy of iron and carbon. Stainless steel also contains chromium and usually nickel as well as smaller amounts of other things depending on the particular type of stainless steel. The iron in stainless steel will rust just like normal steel or plain iron will. However, the chromium on the surface reacts with air and forms a chrome oxide layer that protects the rest of the metal from rusting. For all but a few grades, passivation (treating the steel with citric or nitric acid) is required to remove the iron from the surface and allow the chrome oxide layer to form.

Ray Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2004

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Third of three simultaneous responses -- 2004

Ah steel, something very near and dear to my heart. I'm a blacksmith, and you have to know the material you work. I'm going to throw a lot of information at you as well as some references on the internet.

First off is composition, what is it?

Steel is always a combination of Iron (Fe) and Carbon (C), the percentage of carbon in the mix determines how tough the end product is. For example low-carbon (also known as mild) steel is reasonably soft it has about 0.15% to 0.3% carbon content. Rebar, and decorative ironwork are made from mild steel.

Tools like knives, and other things that need to be sharp are anywhere from 0.5% to 1.6% carbon content.

Anything beyond 2.0% carbon is very brittle, but good for cast parts, engine blocks and other cast metal parts That just gives you an idea as to what carbon does in steel, and (I hope) illustrates just how little is needed to do the job.

Now you have steel, what keeps stainless from rusting? 'Chromium (Cr) is the main additive in stainless steel, it is a very corrosion resistant metal and imparts that property on to steel, a proper piece of stainless has anywhere from 10%-20% Chromium in it. But that's not all there are a few other common elements that are used in steel.

'Manganese, increases hardness and tensile strength.

'Molybdenum, also another that prevents corrosion and also increases strength at high temperatures (think of engine components)

Tungsten forms abrasion resistant particles used for cutting edges, such as metal drill bits.

More on steel at http://www.iforgeiron.com/Blueprints/BP0056_Iron/BP0056_Iron.htm

Good luck, I hope this gets you started.

Marc Banks
- Elizabeth City, North Carolina