Slightly digressing from transformer core materials. I recently noticed a p=
eculiar magnetic anomaly with a stainless steel vacuum type water vessel th=
at I was gifted with. The construction is a double walled flask made by a S=
wiss company called SIGG (I think, going off the logo).
The only weld/joint I can see is where the neck joins onto a threaded colla=
r that holds the stopper.=20
I checked the material for magnetic attraction, Ferritic or austenitic stai=
nless? Ferritic stainless is affected by a magnet, austenitic usually no ef=
fect or very little. This bottle shows no attraction over most of the surfa=
ces including the inside SS liner. But, only on a band approx 10mm wide and=
 30mm away from the weld/joint at the neck there is an area of strong magne=
tic attraction. This is 10 15mm  below  the shape change from straight cyli=
nder to radiused shoulder. Any thoughts as to what may be the cause of the =
localized magnetic effect.  The body material appears to have been formed b=
y spin swageing to shape.
By the way, there are transformers out there with Mu metal cores, trade nam=
es include Permalloy/ Supermalloy. Super high permeability, low saturation =
for special applications, instrument, microphone matching, audio intercoupl=
ing etc.alas not mains power transformers.

Sent from my iPhone

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