Sensitisation instainless steel
Sensitisation instainless steel
(OP)
The effect of sensitisation on the corrosion resistance of austenitic stainless steel is well documentated. My question is - what is the effect on mechanical properties? If a 304 grade stainless steel (i.e. with more than 0.03% carbon) is sensitised by welding or by heating to 700C for 30 minutes do the mechanical properties of the sensitised material alter? Theoretically the precipitation of carbides at grain boundaries might lower the Charpy impact resistance or reduce the tensile properties but does it happen in practice? Does anyone know of any data on this matter?





RE: Sensitisation instainless steel
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Plymouth Tube
RE: Sensitisation instainless steel
Here are some values for 304 SS @ 300F.
304 annealed 80 ftlb
304 sensitized 60 ftlb: 100 hrs @ 1020F
The effect of cold work has a much more pronounced effect than sensitization.
All values @ -300F
304 SS annealed + 0 CW 79 ftlb
304 SS annealed + 10% CW 62 ftlb
304 SS annealed + 20% CW 52 ftlb
304 SS annealed + sensitized +0 CW 60 ftlb
304 SS annealed + sensitized + 10% CW 35 ftlb
304 SS annealed + sensitized + 20% CW 22 ftlb
302 SS sensitized + any CW averages 10 ftlb
Data taken from USS materials Manual for Low Temperature and Cryogenic Steels (June 1966)
RE: Sensitisation instainless steel
i've found this article that probably can give u some good hints on what you're looking.
A Short Review on Wrought Austenitic Stainless Steels at High Temperatures:
Processing, Microstructure, Properties and Performance
http://www.scielo.br/pdf/mr/v10n4/a21v10n4.pdf
S
Corrosion Prevention & Corrosion Control
RE: Sensitisation instainless steel
Many thanks for your help.
RE: Sensitisation instainless steel
No, I don't think that you can measure the effect from welds.
The biggest reason is that there are other issues (chemistry, cold work, strength) that have greater influence on the impact values.
Of course, why in the world aren't you using low C material?
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Plymouth Tube
RE: Sensitisation instainless steel
V-Notch values(ftlb) at a test temperature of -320F
304 SS
Weld Metal 38.5 lbft
HAZ @ 1/16" 51.5
HAZ @ 1/8" 63.0
HAZ @ 1/2" 64.5
304L SS
Weld Metal 48.5
HAZ @ 1/16" 58.5
HAZ @ 1/8" 56.0
HAZ @ 1/2" 75.5
RE: Sensitisation instainless steel
Unclesyd - could you point me to the reference you've quoted? Could be my "get out of jail for free" card !!
Regards
RE: Sensitisation instainless steel
"Data taken from USS Materials Manual for Low Temperature and Cryogenic Steels (June 1966)"
I also have some notes taken a couple of in house seminars that show the essentially the same impact data for SS weldments.
Further references for my first post are:
V.N Krivobok "Properties of Austenitic Stainless Steels at Low Temperature" NBS Circular 520.
E. H. Schmit "Low Temperature Impact of Annealed and Sensitized 18-8" Metal Progress Aug (1950)
They are no further references for the weld impact data shown in my second post.
Here is one article taken from the 10 page Bibliography for this booklet.
"Impact Properties of Stainless Steel Weldments" H.W. Mishler & H.J. Nichols Welding Vol 40 Dec. 1961, pp 564-568
I would try the Linda Hall Library to see if these papers are still available.
http://www.lindahall.org/
RE: Sensitisation instainless steel
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Plymouth Tube
RE: Sensitisation instainless steel
Thanks again - Terry
RE: Sensitisation instainless steel