301 SST magnetic in full hard condition? 1

[UCengno1]

A QC person where I work was using the magnet test to determine if a washer supposedly produced from 301 SST was non-magnetic. I find that there is a 37-45 Rc hardness requirement that can only be achieved in the full hard condition. Am I correct in thinking that the material will be at least slighly magnetic in this state?

BCK

 

[salmon2]

QC is guy is right - 301ss is non-magnetic.

Your concern on hardness is independent with magnetism.

 

[EdStainless]

Yes, full hard 301 will be noticeably magnetic.

"Magnetic Permeability
Properly annealed Type 301 is completely austenitic
and magnetic permeability is 1.02 maximum at 200H.
Cold working promotes the formation of martensite
and the magnetic permeability is increased. The
amount of martensite formed depends on the amount
of cold rolling, temperature of cold rolling, and
composition. Figure 1 shows the increase in magnetic
permeability with cold rolling at room temperature."

Directly from the Allegheny Ludlum Blue Sheet on 301

http://www.alleghenytechnologies.com/ludlum/pages/products/xq/asp/P.17/qx/product.html#

To see the graph.

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[salmon2]

Thanks to EdStainless, something I learned today.

 

[Robertmet]

There is the Ms and Mf but above the Ms there is the Md which is the temperature where deformation transforms the 300 series to martensite. This is often seen in things like 304 cable which may become partially magnetic because of this.It confuses people because they say it's magnetic so it can't be 300 !! We used to make special springs from 301 by rolling to pretty much full hard. As mentioned magnetism and hardness may not correlate !

 

[EdStainless]

If you warm SS before you cold work it you can greatly reduce the martensite transformation. It only changes the mechanical properties a little, but reduces the magnetism a lot. Yo don't have to get hot. Depending on the grade a temp of 250-400F is usually all that you need to see the difference.
This is not a good process though since minor shifts in chemistry will shift the temp required.

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