AWS D1.1 6GR Welding Repair Rates

[bernoullies123]

I am currently on a project where a large portion of the structural welds are under the 6GR position. AWS in their commentary clearly note that this type of weld needs to be done by specialized welders due to the difficultly of the weld joint configuration.

With that said, we are currently experiencing 5%+ repair rates per linear length and over 40% repair rate per joint calculation.

A root cause analysis etc. is being performed to determine the cause, with initially consensus is that the primary concern is in the parameters specified in the procedure.

Anyway I was just wanted to get any feedback from others on typical repair rates noted on their projects specific to 6GR welding.

Thanks in advance.

 

[Kiwi2671]

When you say 6GR welds are you meaning T,K,Y joints ?
If so are they pipe to pipe, pipe to plate or plate to plate ?
Regards,
Kiwi

 

[Mr168]

What process are you using? To some degree, you've already answered your own question. 6GR welds are made with limited access, and require additional welder skill to properly manipulate the electrode.

Electrode angle with FCAW and SMAW processes is the prime candidate for 6GR rejects, as it introduces slag inclusions and porosity from loss of shielding, while IP and porosity are more common with GTAW in my experience.

 

[bernoullies123]

Sorry for the delayed response... am in Asia and Eng-tips is basically blocked 90% of the time??? Getting in via a proxy server.

@Kiwi2671 - T,K,Y joints - yes. 25% CJP pipe-to-pipe, 75% everything-else-to-box (the "everything-else" is another story).

@Mr168 - Process is primarily SMAW, with limited GTAW/SMAW and SMAW/FCAW mixed in. The bulk of defects is equally spread between lack of fusion and slag, with porosity being limited.

My experience in 6GR welds is limited and while 5%+ would of seemed high to me compared to other positions, I cannot find a good baseline to compare, only that AWS notes that it is a difficult weld.

I am doing my literature reviews in the mean time and the only thing I have found which is reasonably applicable is in NORSOK where they indicate 5-10% repair rate range for structural welding...

 

[Mr168]

On my recent jobs here in the States, a 5% reject rate would be a blessing more than it would be considered excessively high, especially for a 6GR.

 

[Duwe6]

Concur that 5% is EXCELLENT! Sufficiently so that I would perform a QA audit of the NDT contractor. My erperience of Ironworkers in the 6GR is that 10-15% is a nominal reject rate.