How Can Stainless Steel Corrode?

"Corrosion of Stainless Steels" by A. John Sedrics on Amazon or eBay or AbeBooks affil link

A. Hi Liljana. Stainless steel is also sometimes called corrosion resistant steel. It's more resistant to corrosion than plain iron or steel, but it's not corrosion-proof. Acids can rapidly corrode it, and salty air can corrode it ... even plain water can sometimes corrode it.

Please tell us what grade you are in and what you know about stainless steel, and then we may be able to help more, but the situation must be explained differently for elementary school students than for college students, as I'm sure you can appreciate.

Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey Need project assistance? Need just a quick answer? 2004

Also, please include what you mean by corrosion. It means different things to different people.

James Watts - Navarre, Florida 2004

A. All "stainless" steels can corrode under the wrong conditions. Many companies, in fact, do not call them stainless steels, but "corrosion resistant" steel. Remember that most of the metal is still iron and can corrode or rust depending on how much stress it is exposed to. One of the worst things you can do to stainless steel is expose it to chlorides. The better grades can withstand a lot of abuse, but most grades can eventually fail when exposed to chlorides in bad atmospheres.

Some grades of "stainless" steel have very poor resistance to corrosion in fact. They are marginally better than carbon steel, but when correctly hardened and passivated or electropolished can give fairly good performance. The grade of steel must reflect the exposure conditions and performance required.

Lee Kremer Stellar Solutions, Inc. McHenry, Illinois 2004

A. Liljana,

Stainless can be corroded, i,e., attacked, depleted and dissolved in the presence of some acids ... but even seawater, which contains salt, as you know, can attack some of the various grades of stainless especially around the welds.

Why the question? What type of stainless are you talking about? Or is this just idle curiosity?

Freeman Newton [deceased] (It is our sad duty to advise that Freeman passed away April 21, 2012. R.I.P. old friend). 2004

A. Regarding the corrosion of stainless steel, I would say stainless steel exhibits good corrosion qualities because of the chromium layer formed on it and this chromium which also contributes to one of its major constituents when exposed to brine, or calcium chloride is corroded (rusting can also be the initial outcome). Acidic attack which can include Hydrofluoric acid, Hydrochloric acid, Phosphoric acid & sulfuric acid can also do the job. Please don't hesitate to ask -- I know a lot about all this.

Shehzad Saleem Khan - Germany 2004