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[MW:33809] Re: HEAT EXCHANGER CONSTRUCTION

By Materials & Welding
One of thought is Nitrogen Purging  in the HEX tubes during PWHT of Shell  to Tube sheet , Tube sheet  to  Channel joints 
Can any one throw light on Nitrogen purging system and its effectiveness ?How it is done / system in market ?
This will keep DSS HEX tubes cool (< 300 Deg C) and serve the purpose 

Thanks and regards

Vishwas - IWE
International Welding Engineer 

On Thursday, October 6, 2022 at 9:52:11 AM UTC+5:30 Vishwas Keskar Welding Manager WELDING wrote:
Dear Experts 
One of HEX involves  following MOCs -
HEX tubes - SA 789 TYP 32205 
Tubesheet -SA 266 CL 2 CS - Tube sheet IS cladded with TYP S32205  overlay.
Shell side - CS -SA 516 GR 70 - 75mm thk 
Channel side - CS- SA 516 GR 70 - 75 mm thk 
PWHT is required for  Tube sheet to Shell welding and Tube sheet to Channel welding. These are butt welds with CS Weld metal .
PWHT is not required for  Tube sheet to HEX Tube  welding due to DSS tube to DSS cladding.

Pl advice for the  care that shall be taken during PWHT  of Tube sheet to Shell welding and Tube sheet to Channel welding.

Thanks and regards
Vishwas - IWE
International Welding Engineer


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