Tube-to-Tubesheet PQR impact test

[ElCidCampeador]

Hi,

I have a tubesheet Thk.120mm Mat. SA 266 Gr.2 and a tube D.25,4 Sp.2,22mm Mat. SA 179 welded to it as for a classic heat exchanger tubeesheet (fig. UW-20.1(d)).

Acc. to ASME VIII Div.1 design calculation tubesheet requires impact test @ MDMT but tube is exempted.

Question: does PQR of this weld require impact test too?

Thank you

 

[SnTMan]

ElCidCampeador, see UCS-67(a)(1), (b)(1). It appears to me your welds will need impact-test qualified.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[MUHAMMAD FAHAD RANA]

Dear ElCidCampeador,

Yes , you have to weld Tube to Tube sheet joint with Impact test Weld Procedure.

I suggest you to go with Mock up (Tube To Tube Sheet Joint) as per QW-193 of ASME Sec-IX 2019 to cope up above stated issue.

Check with your Client Technical specifications as well , they usually required Mock up as well.


Regards,

M.Fahad Rana

 

[r6155]

Use the same PQR made for a butt weld.
No mock-up is required.

Regards

 

[MUHAMMAD FAHAD RANA]

Dear r6155 ,

Can you explain , why same butt weld PQR use in above case , please note PQR qualifies with out impact tested.

As per ASME Sec VIII Div -1 2019 Code , UCS-67 , if either base metal is impact tested by rules of this division , then joint considered to be impact tested , so Impact test WPS shall be use meeting both metal thickness qualification or Mock up qualification.



Fahad

 

[r6155]

@ MUHAMMAD FAHAD RANA
1) QW-193 (2021 edit.) is not for Welding Procedure
2)It is impossible to do a impact test in the tube to tubesheet weld.
3)PQR qualified for butt weld qualify for fillet weld.

Regards

 

[MUHAMMAD FAHAD RANA]

@r6155 , see respond on this:
1) QW-193 (2021 edit.) is not for Welding Procedure:

It deals with procedure qualification of Tube to Tube Sheet Mock ups , when it require by construction code or applicable code or client requirements.

2)It is impossible to do a impact test in the tube to tubesheet weld.

There is no need to do impact test on tube to tube sheet weld , PQR's need to qualify on plate , pipe or other product form but aim is to meet both tube sheet and tube thickness by meeting requirements of UG-84 and ASME Section IX.

3)PQR qualified for butt weld qualify for fillet weld.

Yes you right , PQR qualified with butt weld also qualified with fillet weld , but for groove weld there need to be meet both members thickness if Author having WPS then there is no issue but if he has not , then it is problem , so i suggest to go for tube to tube sheet mock up.


I suggest we put question to ASME to clear understanding on it , or other experts on this forum are welcoming to conclude this thread. Thanks



Regards

Fahad

 

[fleischfresser]

For evaluating if impact tests are required you must follow the rules of UCS-66: "Each component shall be evaluated for impact test requirements based on its individual material classification, governing thickness ....., and the minimum design metal temperature."

The following governing thickness definitions apply when using Figure UCS-66:
for corner, fillet, or lap-welded joints, including attachments, the thinner of the two parts joined.

Therefore in your case the governing thickness is the thickness of the tube. Both materials (SA 266 Gr.2 and SA 179) are assigned to curve B. That means if tube is exempted per figure UCS-66 from impact testing than the forging is exempt as well (exempted for MDMT=-29.5 mm and warmer). And this means no impact test is required for the PQR (see UCS-67).

ASME IX, QW-202.6 require, if specific qualification test requirements are not specified by the applicable Code Section, tube‐to‐tubesheet welds shall be qualified with one of the following methods (for pressure-retaining tube‐to‐tubesheet welds):
(a) groove welds per the requirements of QW-202.2 and QW-202.4
(b) a demonstration mockup per the requirements of QW-193.1

ASME VIII/1 has no specific qualification test requirements. Hence both option can be used.

Additional note: if option (a) is used and impact would be required and thickness of the thinner member (see QW-202.4)is 2.22 mm (as the tube thickness mentioned above) than UCS-66 (d) is applicable: "No impact testing is required for Part UCS materials 0.10 in. (2.5 mm) in thickness and thinner, but such exempted Part UCS materials shall not be used at design metal temperatures colder than −55°F (−48°C)."

Regards
Jürgen

Regards - Juergen