Plug Welding a Hole

[fabengr]

I have two separate contracts where the owner / owner’s engineer is requiring us to plug a misslocated hole. We have a repair procedure written based on information we pull from the AWS D1.1. One of the customers is now asking us for the PQR for the work done to make the repair to the base metal. From the research I have done in documents like AWS, ASTM A6 and AISC N690 (this is a nuclear project) the plugging of a hole is not a joint repair. It is in fact a repair to base metal where welding is used.
Is there any guidance in published literature that someone can guide me too for additional information?

 

[metengr]

fabengr;
I would generate a mock-up for your client and plug weld a sample hole using the concept of a groove weld qualification. Once this is completed,have the coupon evaluated by removing bend and tensile specimens across the plug welded hole.

 

[gtaw]

AWS D1.1 2008 and 2010 (earlier editions as well) have provisions for qualifying a plug weld procedure.

The concern is warranted. I have encountered problems with repaired mislocated holes a number of times. There are several problems that typically occur:
1) incomplete fusion around the circumference,
2) incomplete fusion and slag inclusions with SMAW or FCAW between layers,
3) incomplete fusion between layers when GMAW- short circuiting is used,
4) cracks that resemble a spider web with both GMAW and FCAW, not as often with SMAW.
There are ways of making the repair properly. I have had good success when the welder grinds the hole so that it looks like a canoe. Backing is placed under the hole, and the weld is deposited as stringers as if the excavation was a simple groove weld. Any weaving is limited to avoid entrapping slag.
The circular motion where the welder deposits weld in a spiraling motion from the outside edge to the center of the hole is not the best way to avoid slag inclusions and cracks.


Best regards - Al

 

[Kiwi2671]

fabengr,
Have a look at AWS D1.1 Clause 5.26.5 and also C5.26.5.
The commentary discusses some of the problems Al has noted above.
Regards,
Kiwi

 

[fabengr]

Let me be a little more specific. I have attached a review of several documents that I felt spoke to this issue.
The core to my problem is the question:
Is a hole restoration a weld repair?
I argue that it is not. It is my position that a weld repair is when you are doing work to repair a weld that has already been placed.
This is not a joint and since the WPS we wrote and are following was developed using the appropriate tables in Chapter 3 of the AWS no PQR is required.
Comments?