Tube-Tubesheet Joint -Heat Exchanger

[ankush85]

Hello

I am running with an issue for tube-tubesheet joint. It is a double tubesheet heat exchanger. Tubesheet hole is provided with two grooves for tube expansion.

Hole diameter = 0.756"
Tube OD = 0.75"

Tube Wall Thickness= 0.049" ( Avg).

Tube material= Seamless titanium SB 338 Gr 2

Tubesheet material = SA 240 GR 316 L

Expansion is performed in back tubesheet but still it is leaking. Is there a way to make it leak proof?



Please advise

 

[EdStainless]

Don't over roll it the first time.
Ti has a very low modulus so it springs back a lot. It is easy to over roll.
And then the more that you roll the more leaks appear in adjacent tubes.

I take it that the tube and hole sizes match your mach-up. and that the rolling torque and AWR match as well? Go back and look at the trials carefully. Did you measure pull-out loads (or push out) and do leak tests? If you want to try and additional expansion try it on the mach-up first.

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P.E. Metallurgy, Plymouth Tube