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[MW:7719] Heat Treatment of Heat Exchnager

By Materials & Welding

Hi,

Kindly let me know if my understanding on SEQUENCE OF PWHT of HE is correct or not

1.PWHT on shell side only doe to service (say caustic) or due to thk(say above 38 mm) or LAS or if SS 410 cladded
When specified only heat treatment of shell with one side  tube sheet welded to be done.
Therefater after tube need to be inserted and then after welding of 2nd side tube sheet welding ,local PWHT to be carried out for closing tube sheet to shell to be carried out
Under this criteria tube to tube sheet weld also need to be carried out ,if process requirment(since process fluid from shell side can come in contact with tube to tube sheet weld considering no expansion done on tube) or LAS weld.

 

2.PWHT on Tube side only doe to service (say caustic) or due to thk(say above 38 mm) or LAS or if SS 410 cladded
When specified ,complete channel PWHT to be carried out .
Also tube to tube sheet weld to be PWHT due to process requirment or if metallurgy is LAS

Hence if it is tube side or shell side ,PWHT need to be carried always for tube to tube sheet joint

3.PWHT of complete HE only doe to service (say caustic) or due to thk(say above 38 mm) or LAS or if SS410 cladded
When specified PWHT to be carried out as per  step 1 & 2 i,e without subjecting tubes to PWHT




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