Manual narrow-groove GTAW
Manual narrow-groove GTAW
(OP)
We have procedures developed for our orbital narrow groove welds in material 3"-5", but are contemplating making an attempt implement some manual procedures as well, primarily for tacks and possible repair work due to high/lows on the J-prep that can't be remachined in the field.
Does anyone have any experience with or even seen manual narrow groove on material this thick? We've got approximately .560" of space, and Weldcraft does make a torch small enough with a long enough neck to fit the space. We will likely attempt to pulse the root in as there is no room to walk the cup, but with only a 5/16 cup orifice, gas shielding is a major concern. If anyone has any insight or horror stories, please chime in.
Does anyone have any experience with or even seen manual narrow groove on material this thick? We've got approximately .560" of space, and Weldcraft does make a torch small enough with a long enough neck to fit the space. We will likely attempt to pulse the root in as there is no room to walk the cup, but with only a 5/16 cup orifice, gas shielding is a major concern. If anyone has any insight or horror stories, please chime in.





RE: Manual narrow-groove GTAW
The first problem we encounter was getting a little preheat into the weld area without cooking the welder.
Another was we couldn't carry the proper wire size for the job.
Visibility was a big problem.
RE: Manual narrow-groove GTAW
Our current preheat requirements call for 400 deg. I believe that if absolutely necessary, we may be able to go lower than that and still be within code requirements.
Visibility was a concern for us, which is why we are also looking into a 45 degree cup. We have not ruled out using a gamma plug and getting a camera in to watch the backside of the root.
Was the company you called in able to do the job without a significant failure rate?
Thanks for the response
RE: Manual narrow-groove GTAW
We could get to the backside of our weld. There were no problems with the root. We statred to have problems with the hot pass/passes.
The company was able to complete the job with no problems.
It was an orbital weld, tracked, with a hot wire TIG rig.
With your preheat one is going to hard pressed to get close to the action.
By the way what is the material spec that you are attempting to weld?
RE: Manual narrow-groove GTAW
RE: Manual narrow-groove GTAW
metengr - This setup will pretty much be for the odd man out scenario. I should have emphasized it would be more for repairs than anything. On our last orbital project, we had 2 repairs out of 1400 joints, no narrow groove. On the current project with union welders, 7 out of 7 joints have needed repairs, which is absurd. They've seen a max offset of .020 out in the field, we ran the same program in our test facility with .080 offset, and still produced a root that would pass any NDE you threw at it, so I think you can piece the puzzle together here and grasp what the problem is.
We're currently developing our orbital narrow groove procedures with hot wire AMI units. We'd like to have this as the "just in case" backup plan, because if its physically possible to do, we've got some golden arms who can be brought in to do it.
RE: Manual narrow-groove GTAW
RE: Manual narrow-groove GTAW
We received a demo torch from Weldcraft with a 5" neck on yesterday, and its being flown out to one of our sites for mock up and testing. If it doesn't work, we will start looking into the gas lens possibility.
RE: Manual narrow-groove GTAW