Tube-to-Tubesheet Weld Qualification

[macor]

Hello everybody,
We are planning to conduct Procedure qualification for welding tube-to-tubesheet partial penetration strength weld of HEX. We have chosen to go for qualification by Groove Weld as per ASME IX QW-202.6(a).
The tube thickness is 2.11mm. The thickness of tubesheet is 60mm. Higher thicknesses of tubesheet are also required to be qualified.
The question is: if we want to qualify a WPS utilizing two PQRs, what is the thickness of test coupons to cover the thinner and thicker members. In addition, how about the PWHT requirement for the thin plate and thick plate. Of course, at site we like to avoid PWHT, if possible.

Regards,
MAB

 

[weldstan]

As an Owners' Engineer, I would never permit your qualification method. You would be required to make a tube to tubesheet mockup.

 

[pradipgoswami]

Sec IX-Specifies the following requirements/Options for Tube-Tube Sheet Procedure Qualification. Unless specific requirements are imposed by project specifications,tube‐to‐tubesheet welds shall be qualified with one of the following methods:
(a) groove welds per the requirements of QW-202.2and QW-202.4
(b) a demonstration mockup per the requirements of QW-193.1
(c) fillet welds per the requirements of QW-202.2(c)(for nonpressure retaining tube‐to‐tubesheet welds only).

Out of the above choices, OPTION-B is the best and most reliable and should be followed. Tube to tube sheet weld is not a conventional groove or fillet weld. It needs special welders skills for manual welding as well as operators skills to maneuver the welding head within a tight tube pitch and produce repetitive quality. In some cases for machine welding,equipment qualification is deemed mandatory(per client spec).

Hence option-B as above is recommended.
Thanks.


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[macor]

Hello,
Thank you both for your reply.
You are right that option (b) is the best, but not the only one. Our exchangers are designed per ASME VIII Div1. It does NOT require mock-up for tube-to-tubesheet strength weld. So, during maintenance, with limited resources, we went to the easier one (qualification by groove weld).
But, how we can do it? Can you advice about the PQR thickness and PWHT requirement?

All the best,
MAB