Why does stainless steel get rusty?

Question

I thought it was STAINLESS STEEL! I have stainless steel can openers & spatulas that are rusty. What's up with that?

& did you know that braces on people's teeth are made of stainless steel? That's why they call people metal-mouth. I used to have braces.

Answer 1

Stainless steel is manufactured in a variety of different alloys.

The percent of Chrome and other metals determine which alloy of stainless is produced. Not all versions of stainless is rust proof, just rust resistant.

Not knowing which version of stainless steel you are discussing makes an exact answer difficult. Most stainless steel needs also be exposed to oxygen to retain it's 'stainless' properties. There are also version of steel, Monel and Inconel, that most would consider 'stainless'. Salt water will rapidly affect most versions of stainless with what is called "cloride stress corrosion" which cause a failure of the lattice structure of the metal.

Generally, some stainless steel with a lower chrome content may appear to have discoloration that appears to be rust.

Answer 2

You can rub the rust off with anything, from steel wool to Ajax. Although if you've previously used steel wool to clean it, that could be why it rusts. We had that problem manufacturing stainless steel railing and had to put it together on an aluminum table and polish welds with grinding wheels that never touched steel. What rusts are steel particles picked up on the stainless surface. Another possibility is that some stainless is more magnetic and usually also heat-treatable. It has just enough chrome in it to classify as stainless but can get minor surface rust. Not nearly as much as plain steel, though. Use a scouring powder like Zud or Barkeepers Friend and a cloth or sponge to polish if it's a sheetmetal surface rather than a bar grille, because these have oxalic acid and no bleach. They don't leave corrosive traces of chlorine behind. In fact, oxalic acid reduces rust to iron powder. Which is really neat if you need to clean a small rusty item--stir one of these powders into water, drop in the rusty piece and check it from time to time. Rinse off any abrasive powder, dry it well and oil it. When the rust is gone, it leaves a fine matte finish behind.

Answer 3

steel is a iron alloy with composites like carbon and with a minimum chromium percentage of 10.5 ...and the strength and other properties are closely related to the percentage of carbon and chromium used in it..! its the chromium that creates a thin oxide layer maintaining the lustre by preventing the alloy from forming the iron oxide which is often reffered as rust..so if you got your stainless steel rusted you are betryed by the manufactures and may be they have failed to anticipate the sorrounding environment so that they selected a compostion that best suits..!!



cheers..!

Answer 4

the stainless steel has some chemicals that it will react however most house hold use will not result in rust

Answer 5

Have you ever seen old steel? They usually polish it or throw it away. oxidation will rust iron and most other metals. The steel is not stained , it is rusted.

Answer 6

if its good quality stainless steel than it won't. bu the cheap one yes it does.

Answer 7

well...because they probably got wet and you never dried them. but "normal" steel would rust even in dry conditions...but stainless steel won't

Answer 8

"Stainless" steel is just a coating they put on it to retard the rust.............as in life.............nothing lasts forever but the earth and sky.