Yield and tensile strength of stainless steel SA-240 304L (S30403) at 900 C for a duration of < 3 1

[mrmyagi]

What is the yield and tensile strength of stainless steel SA-240 304L (S30403) at 900 C for a duration of < 3 hours? It is a pressure vessel subjected to a fire.

 

[EdStainless]

I don't have good 304L data, only for 304.
Two heats, tested at 870C, results in ksi.
HT 1; RT 85/37, 870C 16/-,
HT 2; RT 97/59, 870C 17/16, 980C 9.9/6.6

And how about stress rupture, 870C 1000hr, 2.7ksi

You would be lucky if it supported itself.

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P.E. Metallurgy, consulting work welcomed

 

[mrmyagi]

Thanks for the reply, but im not sure i follow.
How long did you test for? What does RT 85/37 mean? Please explain these numbers for a layman

 

[EdStainless]

They didn't say how long they were held, I would presume until stable so likely 45-60 min.
Once stable the properties wouldn't change.
Room Temp tensile, 87ksi UTS/37ksi Yield

Remember that 304L will be softer and weaker at high temp.

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P.E. Metallurgy, consulting work welcomed

 

[mrmyagi]

Thank you for the explanation,

Is 3 h enough time for SS 304L to start creeping?
Can i extrapolate the values from the elastic allowable stress from API 530 Addendum for SS 304L at 816C up to 900C?

The Elastic allowable stress from API 530 Addendum
Table E.11 SS 304/304H @ 816C = 83.1 MPa (12 ksi)
Table E.12 SS 304/304L @ 816C = 52.3 MPa (7.6 ksi)

This vessel is only supposed to last for a 3 h fire and will be be disposed after.
It is supposed to resist 0.15 MPa (22 Psi) for 3 hours. The dimensions are OD=3000mm, t=6mm. Using the pressure vessel formula the required nominal stress is sigma=PD/(2t)= 0.15*3000/(2*6)=37.5 MPa (5.45 ksi).

 

[WKTaylor]

I think for such an extreme condition, one of the heat resistant Alloys... such as Nickel alloys 600 or 625 [etc]... would be required for not only the routine operation for years as a pressure vessel... static/cyclic stresses, errosion and corrosion resistance... but ultimate resistance to the 900C [1652F] long-duration fire as well... after many years of service.

Regards, Wil Taylor
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[mrmyagi]

This vessel has already been built, so it is not possible to pick another material, unfortunately.

 

[EdStainless]

mrmyagi, While that sounds reasonable, vessels often buckle and collapse in fire because both the strength and modulus are dropping. They can't support themselves, though they may still hold pressure.
You cannot extrapolate high temp data as it isn't linear.
At a stress of 5.5ksi you are likely to get significant yielding (remember how rounded SS tensile curves are) but it doesn't sound totally unreasonable.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed