2.75 Stainless Exhaust 304 Stainless Steel Pipe ASTM Spiral 0.8MM Thick

Stainless steel—austenite

There are three main types of structures in stainless steel—austenite, ferrite, and martensite. When you see stainless steel labeled as 18/8 or 18/10 this is telling you how much chromium and nickel is in the steel. The first number indicates 18% chromium, and the second 8% or 10% nickel. The nickel is the key to forming austenite stainless steel. Both the 18/8 and 18/10 are therefore austenitic.

So the “magnet test” is to take a magnet to your stainless steel cookware, and if it sticks, it’s “safe”—indicating no nickel present—but if it doesn’t stick, then it’s not safe, and contains nickel (which is an austenite steel). It is true that if a magnet were to stick to the steel, that it would not be a nickel (austenite) alloy.

And there is a good reason for this—austenitic, or nickel-containing, non-magnetic stainless steel, is highly resistant to corrosion, which is super important if you’re cooking directly on it. If the piece was fully magnetic stainless steel, it would corrode and not last very long without the nickel to stabilize the metal. Even though it would be nickel-free, I don’t think I would even want a magnetic, 18/0 stainless steel pan for this reason!

304 Stainless Steel Pipe Specification