Non-magnetic Stainless Steel???

[Roger L. Elowitz]

Hi Guys, 

Looks like many of us have been snookered. Thank goodness the "Fact Police"
are on the case. 

Not long ago this post by Bill, W7TI (ex-W7LZP) wrt@eskimo.com appeared:

"If I may offer a suggestion which is well known to the boating crowd:
Wherever you do your shopping, take a small magnet with you.  Really good
quality stainless steel is non-magnetic.  Any SS that is magnetic is poor
quality and will not last nearly as long.  There's lots of the bad stuff
around, so it pays to be cautious."

Ok! I know beans about stainless steel, but I do know all steel is made from
iron. So, any steel that is non-magnetic would indeed be some wonderous
stuff. I immediately went to my silverware drawer where loads of knives,
forks, spoons etc. have resided for years after having been abused in
dishwashers and everywhere else immaginable. Not one of these pieces rusted.
All (or almost all) allowed magnets to be attracted to them. 

I did say almost all. To my surprise, a fork from an Oneida Ltd. serving set
with the identical pattern as the rest of the set showed no magnetic
attractivity at all even though it was marked "stainless!" However, it was
badly scratched and that leads me to believe that while it is stainless- it
is not steel like the rest of its mates.

Now, this point lead me to research steel making in the Encarta95 CD ROM,
looking under the heading of Science and Technology, Iron and Steel Manufacture.
There I found this section on Stainless Steel that I have excerpted for your
information:

Stainless Steels 
Stainless steels contain chromium, nickel, and other alloying elements that
keep them bright and rust resistant in spite of moisture or the action of
corrosive acids and gases. Some stainless steels are very hard; some have
unusual strength and will retain that strength for long periods at extremely
high and low temperatures. Because of their shining surfaces architects
often use them for decorative purposes. Stainless steels are used for the
pipes and tanks of petroleum refineries and chemical plants, for jet planes,
and for space capsules. Surgical instruments and equipment are made from
these steels, and they are also used to patch or replace broken bones
because the steels can withstand the action of body fluids. In kitchens and
in plants where food is prepared, handling equipment is often made of
stainless steel because it does not taint the food and can be easily cleaned.


"Iron and Steel Manufacture," Microsoft (R) Encarta. Copyright (c) 1994
Microsoft Corporation. Copyright (c) 1994 Funk & Wagnall's Corporation.

Nowhere does it say anything about any steel being NON-MAGNETIC! There are
lots of metals that do not "rust." Check the coins in your pocket for
example and ask any kid who's tried to lift them out of a sewer with a
magnet on a string that- it only works on the "steel" pennies made during WWII. 

So, after extensive reading about everything I never wanted to know about
iron and steel making- (really fascinating stuff) I realized that the
manufacture of stainless steel is not a coating process or surface treatment
and that, depending on the addition of various other metals you can end up
with stainless of all grades of hardness and strength. 

What's more, there is no way under the sun (or sea) anyone with a pocket
magnet can determine the "quality" of stainless steel products- marine or
otherwise.
What you can tell instantly however is that if the magnet doesn't "stick,"
then while the metal may not "rust" it is most likely not a ferrous (steel)
product and quite likely, not as strong as a steel product. I do know there
are non-ferrous metals that have strengths far greater than any steel- but
it's not likely any of us would be able to afford using them- if we could
ever find a source.

I did not intend this piece to be a "flame" to Bill, W7TI, but if it seems
so let me take this opportunity to appologize after the fact. However,
unless we constantly question the sources of the information we get here on
the reflector it is sometimes difficult or outright impossible to tell fact
from opinion (testimony) and myth- my statements included. 

If I've done my job as an undercover operative for the "Fact Police" I
should get a promotion. Next, I'd like to investigate- "If applying Noalox
to the outer surfaces of the aluminum tubing makes the tubing slippery
enough to improve the gain factor of any beam by 2-dbi while doing nothing
for the F/B ratio."  (Perhaps only the stuff with the copper particles
imbedded in it does that.) Is it really the "RF Grease" we've been reading
about in all those April issues of QST? Will it really keep pigeons off the
beams? And while I'm at it, I'd like to find out how to remove Noalox stains
from my clothing.

Well, it's back to the books for me.

73 All,

Roger, K2JAS 


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