What grade stainless ?

[oldskool]

isnt the lower grade stainless magnetic?

[Rusty]

I believe it is.

[HPmuirt]

but tell me this - is there an easy way to determine if a lump of stainless steel is 303 or 304 without taking it for expensive lab tests ?

Stick a tiny piece (a couple of mm only) in an envelope and post it to me - you have my address - and I'll tell you the exact chemical composition. I have a room full of scanning electron microscopes with x-ray detectors so I can measure the exact chemical composition to within thousandths of a percentage

That said, since I am not a metallurgist you'll then have to work out what that particular composition equates to in terms of ss grades but that should be easy on here.

Cheers n

Si

[magarv]

isnt the lower grade stainless magnetic?

That is not always the case. It depends on type of SS steel.

It is correct that i.e. 304 is slightly more magnetic than 316. But materials like UNS S32750 wich is a very high grade SS steel and way better than 316 both regards to corrosion and material properties is magnetic due to the ferritic/austenitic structure.

The austenitic stainless steels like 304, 316, 321 etc are "non magnetic" , while ferritic/austenitic stainless steels like the different duplex grades are magnetic.