304 SS in high temperature serviec
304 SS in high temperature serviec
(OP)
Dear all,
Without specifying the minimum carbon content or "H" grade , can plain SA-240-304 SS, which has carbon content from very low up to 0.08% maximum, be used for 536 degC design temperature ? My understanding is only above 540C, high carbon content 0.04% and above is recommended.
Without specifying the minimum carbon content or "H" grade , can plain SA-240-304 SS, which has carbon content from very low up to 0.08% maximum, be used for 536 degC design temperature ? My understanding is only above 540C, high carbon content 0.04% and above is recommended.





RE: 304 SS in high temperature serviec
RE: 304 SS in high temperature serviec
"At temperatures above 1000°F, these stress values apply only when the carbon is 0.04% or higher on heat analysis."
The minimum carbon content of 0.04% is required only if you are operating over 1000F. Below that, you are correct that any plain SA-240 SS304 will do. I am assuming Section VIII-1, check with Code your using.
RE: 304 SS in high temperature serviec
RE: 304 SS in high temperature serviec
Might specify C of 0.04 Min on any P.O., just to be covered.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: 304 SS in high temperature serviec
RE: 304 SS in high temperature serviec
In general you either get 304L (0.01-0.03% C) or 304H (0.05-0.08% C), there is almost no straight grade material made these days.
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P.E. Metallurgy, Plymouth Tube
RE: 304 SS in high temperature serviec
When we specify SA-240-304 SS on vessel drawing according to Section II designation, what will we get from the MRT ? Will it say 304L or 304H ? Shall we reject it if it says 304L or 304H ?
RE: 304 SS in high temperature serviec
If it is low C, at elevated temp it will only be as strong as 304L so double check your design. If creep is an issue you need to look again.
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P.E. Metallurgy, Plymouth Tube
RE: 304 SS in high temperature serviec
A design temperature of 536 C implies an operating temperature a fair bit below 536C. Based on past experience, which is all for equipment of fairly limited size, we've never had a problem as long as the appropriate stress values for the material actually being used are used in design.
If it is a condensate pot, what is condensing at those high temperatures?
If you are actually using the equipment at lower temperatures with potential aqueous corrosion, but have a high design temperature due to an upset condition, you are actually in a bad place to use H grade. Low carbon content will reduce sensitization in the heat affected zone, relative to using straight or high carbon grades. In these situations people often consider stabilized grades like 321 and 347.
RE: 304 SS in high temperature serviec
Creep shall not be the concern in my opinion. And we have decided to stay with straight 304 SS without asking high carbon content.
RE: 304 SS in high temperature serviec
Can dual certified 304/304L SS be used for high temperature between 800F -1000F for long term service?
For 304L, Div 1 does not allow above 800F. I believe it is due to low carbon that it won't have sufficient rupture strength.
Since dual 304/304L also has very low carbon, I don't think it can be used above 800F. Is it right ?
RE: 304 SS in high temperature serviec
RE: 304 SS in high temperature serviec
RE: 304 SS in high temperature serviec
No worries. When you stop learning it is time to get out of this business.
RE: 304 SS in high temperature serviec
The problem with sloppy work is that the supply FAR EXCEEDS the demand