[TowerTalk] Magnetic 304 SS- Huh?

[Big Don]

Our 80' Rohn 25 with 4 guy sets has been up since 1977.  The lower guy set
is 3/16 stainless looked good, came with the used tower, and had been up
previously for a few years in KH6).  There is zero rust on it (2 miles from
Puget Sound salt water).  FWIW, just tested it, and  it *IS* indeed
 magnetic..
Don  N7EF
.

On Thu, Mar 28, 2013 at 11:46 AM, Al Kozakiewicz <akozak at hourglass.com>wrote:

> 300 series stainless steel alloys are austenitic; 400 series are
> martensitic.  300 series is formulated with nickel and a higher amount of
> chromium in the composition than 400 and are more corrosion resistant.
>  Unlike the 400 series, the 300 series cannot be heat treated (well,
> technically you can heat treat anything, but it will have little effect on
> the physical properties of this steel).
>
> Magnetism is determined mostly by the crystalline structure of the alloy.
>  The introduction of nickel promotes the formation of austentite which is
> non magnetic.  However, cold working creates pockets of martensite which is
> magnetic.  304 is especially prone to this formation when cold worked; wire
> and cable making is all about cold working steel.  Wire is formed by
> drawing steel rod though progressively smaller dies.
>
> I think you would be hard pressed to find any 304 alloy stainless wire
> that is not magnetic unless it was annealed after working.
>
> Al
> AB2ZY
>
> ________________________________________
> From: TowerTalk [towertalk-bounces at contesting.com] On Behalf Of Brian
> Alsop [alsopb at nc.rr.com]
> Sent: Thursday, March 28, 2013 1:18 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] Magnetic 304 SS- Huh?
>
> Guys,
>
> I purchased a roll of 3/16" SS wire rope which was clearly labeled
> 304SS from Home Depot.
>
> When I got home, I tested it with a magnet.  It was highly attractive.
> It gets returned.
>
> I know there are some kinds of SS which show magnetism.
>
> I think the explanation is "made in China" rather than some magical
> change in SS 304 properties as it crosses the Pacific.
>
> Am I wrong?
>
> 73 de Brian/K3KO