Re: [Harp-L] This Stainless Steel thread

[Joel Fritz <williemctell@xxxxxxxxx>]

OK, here's the deal on stainless steel and magnetism.  Steel has several 
different possible crystal structures.  The austenitic structure in 
chrome stainless steel like that used in cookware, sinks, and a lot of 
other applications is non-magnetic.  However, if this variety of 
stainless is heated to temperatures above a critical point that varies a 
bit with alloy composition and not cooled rapidly to room temperature, 
the crystal structure will be a mixture of  (mostly) austenite and 
ferrite.  Ferrite is magnetic.  Thus the area around welds is sometimes 
magnetic.  The ferritic structure is much more prone to corrosion, thus 
the rust you sometimes see near welds in stainless steel.



On 6/10/2012 5:08 AM, Aongus MacCana wrote:
> There are various grades of stainless steel depending on the alloying
> components. Here in Ireland the plumbers' rule of thumb on the quality of
> stainless steel kitchen sinks used to be whether they would attract a magnet
> or not. If they were not magnetic "they were the right stuff". If a magnet
> was attracted to them they might be inferior and subject to slight rusting.
>
> I made the interesting discovery that some of the new Euro coinage, must
> have a ferrous component. I had a keyring attachment for holding a metal
> token which could substitute for a Euro coin when releasing a supermarket
> trolley. I lost the token, but lo and behold if the magnet of the token
> holder in my pocket did not attach itself to a real Euro. By the way I do
> not plan to put a magnet near the stainless reeds of my trusty Seydel 1847
> anytime soon.
>
> Beannachtai
>
> Aongus Mac Cana