<VV> Was: engine lid support, Now: metallurgy (no Corvair)

[Dale Dewald]

At 01:27 PM 11/6/04 -0500, Marc Sheridan <sheridanma@adelphia.net> wrote:

>Joe,
>I tried your magnet test and sure enough, the magnet stuck to my shiny
>engine lid support. So then I went on to test other things. The magnet
>was attracted to all the stainless trim from my Corvair, that is now in
>a pile in the garage while my car is in the body shop. After that I
>headed to the kitchen, the magnet would not stick to my stainless steel
>sink. From that, I could have decided that the magnet test is valid and
>the trim on my car is not stainless, but I searched out a pan that had
>"stainless steel" stamped right in it. The magnet stuck!
>
>So now my conclusion is that many stainless steel items, like Corvair
>trim parts, are not 100 per cent stainless, but an alloy that has enough
>regular steel in it to be attracted to a magnet. Is my conclusion correct?

The windshield and drip molding trim on the Corvair is made from a 
stainless alloy containing Iron (Fe) + Chromium (Cr).  Fe and Cr are two 
metals that exhibit magnetism; Cobalt (Co) is the third.  Simple Fe-Cr 
stainless steel alloys work fine for many applications and are relatively 
low cost.  For more aggressive environments or when extensive metalworking 
is required, Nickel (Ni) is added to make a Fe-Cr-Ni stainless steel.  Ni 
improved the corrosion resistance in salty or corrosive atmospheres and at 
higher temperatures.  In sufficient quantity Ni alters the crystal 
structure of the alloy to make austenitic stainless steel, which is 
nonmagnetic.  Austenite has the same crystal structure as copper and 
aluminum and is therefore quite ductile--ideal for deep drawing a one piece 
kitchen sink, for example.  I hope this explains why some "stainless 
steels" are magnetic and some are not.

Note: Some of the exterior trim on the Corvair was made from anodized 
Aluminum.  The emblems were cast with "pot metal," a Zinc-based alloy, and 
them chrome plated.

Dale Dewald
Hancock, (UP) MI