[TowerTalk] Magnetic 304 SS- Huh?

[Al Kozakiewicz]

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


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