Re: Stainless Steel

[Richard Bies <bies@domain.elided>]

Some years ago, my kids noticed the varying magnetic property of stainless
steels.  So to enliven the dinner-table conversation, I inquired "how's
that..." of a research ghuru at USSteel I knew.

The answer is not simple -- the alloying to make the "stainless" property
moves the eutectoid (making it somewhat more likely that the material will
crystalize in a non-magnetic state), but that ultimately the heat-history
will also determine whether or not the material is magnetic (the magnetic
domains have formed).

So the magnet test may not give the alloy fully accurately.

(The eutectoid is a point [probably imaginary] in time/heat from which the
various forms may solidify -- what is played-with in tempering (and I
imagine forming hi-strength body panels) and annealing -- depending on how
quickly the steel is coooled.)  The magic in steel.

r.m.bies
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