Welding Joint Repair 1

[Inchtain]

I would appreciate it if you could inform me whether it is allowed to repair a root defect in an 8" and 12" pipe welding joint from inside of the pipe by chipping off the defect and welding the root pass again.

Thanks

 

[goutam_freelance]

B 31.1 or B31.3 does not forbid the repair of the root defect of welding. The repaired weld has to undergo NDT as per code, and a qualified welder to be used.

However, it may be difficult to weld a 8" pipe from inside.

 

[weldstan]

It cerrtainly has been done on large diameter pipe and is not prohibited under B31.1, B31.3, B31.8 and other Codes.

 

[r6155]

What code is...?
Is this a new construction project?
What type of defects?
Was the joint completed or just the root pass?
Thickness of pipe, material?

 

[EdStainless]

What are your clients rules about weld repair?
Commonly you would have to grind it out, then perform NDT to show that you are into sound metal, and then re-weld.

 

[Inchtain]

What code is...?
Is this a new construction project?
What type of defects?
Was the joint completed or just the root pass?
Thickness of pipe, material?

ASME B31.3
Replacement project
Burn through
The joint was completed
8" 8.18mm and 12" 12.7mm

 

[LittleInch]

Why can't you get to the outside of the pipe?

 

[Inchtain]

Why can't you get to the outside of the pipe?

No problem with that, but I look for permitted options

 

[DekDee]

ASME B31.3
Replacement project
Burn through
The joint was completed
8" 8.18mm and 12" 12.7mm

If you can access to reweld it is obvious you can visually examine.
What about all the joints without visual access or no NDT ?
Suggest an investigation of welder / s responsible would be a good idea.

 

[r6155]

Is there complete documentation of defective welds?
NO: Repairs are not permitted.
YES: Be practical and consider cutting out the entire weld and welding a new one instead of a local repair.

 

[Inchtain]

Is there complete documentation of defective welds?
NO: Repairs are not permitted.
YES: Be practical and consider cutting out the entire weld and welding a new one instead of a local repair.

Hello and thanks for the reply.
Yes, there is RT report'
But, by cutting and rewelding the joint, you are risking losing the proper dimensions needed for the piping as it is part of a long system replacement

 

[r6155]

The Complete documentation is: base material, electrodes used, name of welder, date, WPS, visual inspection report, PWHT, preheat, RT, .....etc.. etc.

 

[Inchtain]

The Complete documentation is: base material, electrodes used, name of welder, date, WPS, visual inspection report, PWHT, preheat, RT, .....etc.. etc.

Of course, I didn't mention these, because they are all provided and do not related directly to my question (No PWHT required)

 

[Mark_Markus]

Yes, internal root repair is typically permitted the defect is fully removed.

 

[DekDee]

There is no issue with what you propose.
However, consider what I noted previously.
If you are getting root repairs on welds visually accessible internally then what about the rest of the welds in that "lot" ?
If it is 100% NDT then no problem.
If it is 5%, 10%, 20% and you have radiographed weld neck flanges and you have root defects then you have a problem.
A welder problem.
Any half decent pipewelder will visually inspect their completed weld internally if accessible.
If he / she has walked away from the weld and RT discovered something that should have been picked up visually then you have a problem

 

[r6155]

Good luck.