qualifying tube to tube sheet welds

Joe,

Welding of tube to tubesheets is commonly referred to as "seal welding". Seal welds are not considered as strength welds......tubes are still expansion rolled into the tubesheet

Seal welds are commonly made to remove a crevice in the heat exchanger.... a site of corrosion.

As I recall, tube attachment to the tubesheet is typically "pullout tested" as described in the TEMA standards. This destructive test is performed on a group of representative tubes rolled into a sample section of tubesheet.


MJC

You should review ASME B&PV Code, Section VIII, Div 1 Part UHX-15. If the tube-to-tubesheet weld is only a seal weld to prevent leakage (versus a partial or full strength weld), ASME code does not specify any further qualification. Typically, we have required a mock-up to demonstrate adequate fusion and pull-out strength. This is above and beyond ASME code requirements.

You can referee to EEMUA143 from Engineering Equipment and Materials Users Association.

more info on
best regards

MJC
ypically a T to T/sht weld can be a seal weld if the expansion of tubes into grooves in t/sht is giving the strength. However it is possible to use welding for strength and expansion of tubes for strength as well and in rare cases both expansion and welding contributing to strength. Refer Appendix (non mandatory in Sec VIII Div 1 especially for calculating fr...I don't remember which appendix|)

For tests on t to t/sht welds, refer OCMA, EIL and/or TEMA for other tests. Some specs also call for sectioning a slice and carrying out radiography in addition to tear tests and pull out tests. I had presented a paper on types of tests available for t to t/sht welds but do not know how to append the same here

Thanks and regards
Sayee Prasad R CEng MWeldI MIOMMM


If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!

you can use your std welding procedures taking in consideration the thickness of base and tube mats,

The design of the weld is critical of the Code construction
you have to choose the design and comply with fillet, groove and size of the weld metal, joint desing.
ER