CS overlayed with Titanium?
CS overlayed with Titanium?
(OP)
Hi,
we have several heat exchangers with CS + Ti cladding on tubeside selected because the service is sea water (máximum operating temperature: 47ºC). The tube and the tubesheet shall be Ti and CS + Ti cladding (tubeside) respectively with a strength weld joint.
My question is:
1) Any references/experiences in the restauration of Ti cladding, i.e, weld overlay for the tubeside courses. Do you have any weld overlay welding procedure (Ti overlay with CS base material).
2) Any references/experiences with Ti lining for this particular application.
A prompt answer will be very appreciated
Thanks in advance
Peter
we have several heat exchangers with CS + Ti cladding on tubeside selected because the service is sea water (máximum operating temperature: 47ºC). The tube and the tubesheet shall be Ti and CS + Ti cladding (tubeside) respectively with a strength weld joint.
My question is:
1) Any references/experiences in the restauration of Ti cladding, i.e, weld overlay for the tubeside courses. Do you have any weld overlay welding procedure (Ti overlay with CS base material).
2) Any references/experiences with Ti lining for this particular application.
A prompt answer will be very appreciated
Thanks in advance
Peter





RE: CS overlayed with Titanium?
Can you give a little more information about your Hx construction.
The shellside of the tubesheet is Ti?
What is the tube layout and pitch?
You have a strength weld on the shellside?
Why do you need to repair the Ti side?
RE: CS overlayed with Titanium?
herebelow you have the requested information:
MOC
Shell side: CS
Tube side: CS + Ti clad.
Tubesheet: CS + Ti clad (on tubeside)
Tubes: Ti
TEMA type: There are different designs (AEL, AJL, NEN, BJS, BEM, BJM, BES and HES.
Strength weld joint on tube side.
Tube pitch: 25.4 - Layout: 30
I mean with Ti restauration, the reposition of cladding (with weld overlay) on circunferentials and longitudinal weld courses.
regards
RE: CS overlayed with Titanium?
Weld overlay cladding of Ti on CS is NOT possible.
Tubes are roller expanded into the CS tubesheet and then seal welded to the face of the cladding. Whether this is considered a "seal" weld or a "strength" weld depends on the thickness of your tubes I guess.
It's also possible to loose-clad a tubesheet with Ti, similar to what is done with tantalum etc.
RE: CS overlayed with Titanium?
RE: CS overlayed with Titanium?
Channel construction cannot be Ti clad / overlay for the reason mentioned above, i.e. you cannot weld Ti to CS or other common backer materials.
We have used CS channels with an interior coating of Plasticor or similar material, and with anodic protection. This is important as the CS material will preferentially corrode quickly if any flaws develop in the coating. We have used both passive and active anodic systems.
Another option is an alloy channel of a weldable material. AL-6XN is sometmes specified for these services, and my understanding is that it can be welded to CS. BTW, your N-type channels will be a potential problem in Ti-clad TS and CS channels, as you cannot really seal the crevice where the channel cylinder overlaps the TS. A gasketed A-type channel is a better design.
Your floating heads could be troublesome, although I suppose an interior coated CS design with passive anodes is possible, and again solid alloy is an option.
Hope you find this useful, sorry for the late reply, too much work lately.
Regards,
Mike