Chris69

I thought you could check stainless steel with a magnet to see if it sticks. I bought a 'stainless' collector reducer set with bolts. The bolts don't stick, but the reducers do, even though the metal looks like stainless. What's up with that?? :confused:

Smokehouse69

There are many different alloys that are called "stainless steel" There are 304,308,316 stainless steel, just to name a few. Typically the ss that is used on exhaust systems, especially the ss on mondern exhausts has a lot less nickel and chromium in it than higher grades of stainless. This alloy has a fairly high proportion on ferrous (iron)compounds so it does have magnetic properties.
I have a set of SS exhaust manifolds from a C4, they are slightly magnetic and do "rust," sort of. They get a red dust coating on them when exposed to high temps, but they do not pit or corrode away like mild steel.

gmcclurg

As Smokehouse said, all stainless is not equal. 300 Series is non magnetic and is the most stain less of the stainless steels (higher nickle content). 302 and 304 are used in foodservice operations quite a bit, the higher 312and 317 resist many harsh chemicals and are used in Photo processing. 400 series has more carbon steel and is more prone to rust. The best place to buy high quality S/S nuts and bolts is a marine supply store, but take a magnet with you. Chlorine will attack all stainless and never clean stainless with steel wool. The splinters get in the stainless and start to rust. For most automotive applications, 400 series will work fine.

Chris69

Thanks all. Once again, this Forum comes through with the details! :cheers: