Rejected PQR for Tube-to-Tubesheet Welding Procedure 1

[Husaam]

Dears,

We performed welder qualification mockups for tube-to-tubesheet welding procedure. 15 mockups for three welders (5 each). All of the mockups failed due to lack of penetration and lack of fusion defects as noted from the macro test.

I would like your advise to determine how we can improve the performance of our welders to avoid the same defects in future PQRs.

Regards,

 

[DVWE]

Have your welders practice more, and if that doesn't work, hire a welder training consultant knowledgeable with the specific type of weld joint and welding process to work with your welders.

The devil is in the details; she also wears prada.

 

[Tmoose]

What welding processes are you qualifying?

 

Retain an actual welding engineer, and since this is a specialized application, retain an actual welding engineer with actual T/TS experience.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Husaam]

Thanks all for the responds. We are qualifying,
Process: GTAW
Tube diameter/thickness: 19.05mm OD/ 2.11mm
45 degrees groove with the tubes expanded before welding
1.6 filler with two passes

We are suspecting that the narrow groove and the fact that the tubes are expanded contributed to the lack of penetration defects. But we can't do anything about it since this is the case for the actual welds. We are considering to bring a third party to do the welding for the exchangers but we have to do the qualification again to have our own qualified WPSs for the future.

 

[weldstan]

This type of weld has been made many times by other manufacturers' welders on carbon and low alloy steels. I would question adequate cleaning and too low a current as well as welder inexperience and lack of training.

I note that the materials to be welded have not been stated nor the tubesheet thickness.

 

[Husaam]

Tubesheet material SA266 Gr.4 (50mm) and the tubes are SA 179.

Really appreciate all of your comments.