Is there any reason that 316L Stainless Steel would need hardness tested after a fire? 2

[jeevesme]

We have a vessel that has seen an internal fire. The temperatures hit the temperature limit of the probes at 850F. The temps went from ambient to above 850 back to ambient in 4 days time. I know there is the possibility of (low possibility) Sensitization. However, corrosion resistance is not an issue because it in a non-corrosive process. My engineer is insisting on hardness testing be performed. I disagree. I have done a lot of hardness testing in many different plants but never on stainless.
What information would we gain from hardness testing 316L? What method should be used, Portable Vickers, Brinell? Does anyone know the acceptable ranges of hardness for 316L SS? I can't seen to find any ranges listed anywhere.

 

[metengr]

I would not waste my time with hardness testing because 316L stainless is not hardenable by heat treatment. Worst case, I would perform a good visual examination and look for warpage or buckling.

 

[EdStainless]

I agree with Metengr, it would be a waste of time.
Sagging or warping would be where I would look.

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P.E. Metallurgy, Plymouth Tube

 

[jeevesme]

Both of your answers confirm what I have read everywhere else. Thanks for the quick reply guys.

 

[mfgenggear]

found this on the web
HEAT TREATING

316/316L is not hardenable by heat treatment. Cold working increases tensile strength and hardness. Annealing range is between 1850° and 2050°F. Cool rapidly. Water should be used for heavier sections; air for lighter sections. The stress relieving range is between 400° and 750°F.
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added

http://www.aksteel.com/pdf/markets_products/stainless/austenitic/316_316l_data_bulletin.pdf

 

[jeevesme]

Would performing Ferrite Testing tell us anything? Could we do this in-lieu of in-situ metallography?

 

[EdStainless]

Not that I can think of. Unless you think that you reached 1800F, in which case your structure is a bigger issue.

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P.E. Metallurgy, Plymouth Tube