CS Tubesheet, 304 Tubes, 500degF
CS Tubesheet, 304 Tubes, 500degF
(OP)
Fellows,
I am replacing an exchanger that has a carbon steel tubesheet and 1" 304 tubes. The shell side operates at 500degF. Besides service/corrosion concerns (we have those lined out), are there mechanical issues with the tube to tubesheet joint?
I feel the difference in thermal expansion between the CS and 304 may cause an issue with joint leaks or perhaps elevated stress at the rolled joint. If I were to strength weld the TTS joint, there is a dissimilar weld issue to deal with...perhaps with a 309 tubesheet overlay and a 309 to 304 strength weld.
Any experience with these dissimliar bundle materials and these temperatures? If this is not an issue for these temperatures, is there a calculation that can be performed to verify other instances with different materials, tube diameters, etc will perform reliably?
I am replacing an exchanger that has a carbon steel tubesheet and 1" 304 tubes. The shell side operates at 500degF. Besides service/corrosion concerns (we have those lined out), are there mechanical issues with the tube to tubesheet joint?
I feel the difference in thermal expansion between the CS and 304 may cause an issue with joint leaks or perhaps elevated stress at the rolled joint. If I were to strength weld the TTS joint, there is a dissimilar weld issue to deal with...perhaps with a 309 tubesheet overlay and a 309 to 304 strength weld.
Any experience with these dissimliar bundle materials and these temperatures? If this is not an issue for these temperatures, is there a calculation that can be performed to verify other instances with different materials, tube diameters, etc will perform reliably?
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RE: CS Tubesheet, 304 Tubes, 500degF
RE: CS Tubesheet, 304 Tubes, 500degF
What is the TEMA type of your heat exchanger ?
BEM.. AEU ????
Is there an ASME plate with allowable temperatures and pressures....... or is this a older HX to be reused in a new service ?
-MJC
RE: CS Tubesheet, 304 Tubes, 500degF
I have had lots of experience with high pressure Hx's with SS tubes expanded (rolled, explosively and hydraulically) into thick CS tubesheets and seal welded at a typically 309 overlaid tubesheet. The shell side temps ranged up as high as 8-900F.
Your service, on the other hand might have to do with detrimental effects to the above configuration.
We need to know more to help with any tips.
rmw
RE: CS Tubesheet, 304 Tubes, 500degF
In the end, I'm looking for general guidance on how to put numbers to this issue in the future. Any thermal expansion/tubesheet calcs that help
with this assessment?
I wul have to reconfirm the service with process, but I don't know how that will affect the tubesheet joint design. Also, don't have the tubesheet thickness ATM, but would guess 3.5 to 4"
Thanks gents!
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