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[MW:34662] Tube to Tubesheet weld- MLP value Inquiry

Dear Sirs,

We are fabricating a heat exchanger , designed as per ASME Sec VIII Div-1, 2021 Ed. 

with SS 304 Tube to Tubesheet welds, designed as per ASME Sec VIII Div-1, UW-20.1 "C " joint , strength weld type with 2 passes of GTAW welded from root.

We did PQR recently as per ASME Sec IX QW-193 2021 ED. requirements.

with ref. to the below joint sketch used for the actual weld joint , welded in the heat exchanger which is referred from the fabrication drawing,

for the PQR,  that is for MLP value as per ASME Sec IX QW-193.3 , can we use 0.7xt , where tube thk is 2.11 mm , so can we accept MLP as min. 1.48mm for all 10 tube welds?

Or from the root, the throat value shall be 4 x0.7, that is Min. 2.8mm for MLP based on the below sketch with leg size 2 mm and bevel depth 2 mm, totally 4mm weld ?

So which minimum value shall be used for acceptance , either 1.48 Or 2.8 mm for the MLP based on the above statements?

The actual measured MLP values received are 2.6 to 3.2 mm from the test lab, for 10 tube welds .



Please reply with your opinion for MLP value acceptance, before I submit these test report values to ASME AI for his review and stamp on the PQR.

Thanks and Regards,
Saravanan Sornam,
S.Korea.


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