PT / MPI for root Weld
PT / MPI for root Weld
(OP)
Hi friends,
Well , one question came in my mind while discussion with some inspection engineers , that , In a butt welding , ( Joint is single V and diameter is 43" ) we are doing the GTAW in root and hot pass , so after completion of Weld , Is we need to do PT / MPI from root side ? We are doing PT / MPI from face side ( top side not inside )
Is any code reference for the same if required or if not required then there is any code reference ?
Kindly help us ..
Regards
nAVIN
Well , one question came in my mind while discussion with some inspection engineers , that , In a butt welding , ( Joint is single V and diameter is 43" ) we are doing the GTAW in root and hot pass , so after completion of Weld , Is we need to do PT / MPI from root side ? We are doing PT / MPI from face side ( top side not inside )
Is any code reference for the same if required or if not required then there is any code reference ?
Kindly help us ..
Regards
nAVIN





RE: PT / MPI for root Weld
RE: PT / MPI for root Weld
So, doing a DP NDE exam on the outside of the final pass does NOT tell you that there are no pits or holes (1) in the top or bottom layers of the root (2) in the top or bottom layers of the fill passes (3) in the bottom layers of the final cover pass.
A mag particle test (MT) test can find cracks or holes below the final layer of steel in the final pass, but they are not perfect either. I'd recommend a DP test after the root pass is complete. A DP test inside the pipe is not normally required (usually the inspector can't fit!) but should be done on the prep of welds that are back-ground and then welded from the back side to get a double penetration weld.
All of these requirements should be in your company's NDE spec's. Or in your client's NDE spec's for each different kind of piping and pipe material and service condition. NDE requirements are NOT generic, but specific to service, pipe material, temperature, pressure, etc.
RE: PT / MPI for root Weld
Any PT in a confined space is dangerous, and requires forced ventilation and/or serious respiratory protection. Not to mention the flammability. One spark, you are a candle.
RE: PT / MPI for root Weld
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Any PT in a confined space is dangerous
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absolutely , there is No doubt.
=
Thanks to all
RE: PT / MPI for root Weld
Dry MT is the most common NDE technique used for surface root inspection. It is immune to heat and is going to give you what your looking for- cracking.
This is all assuming that the material in question is non-ferrous.
Hope this helps.
East
RE: PT / MPI for root Weld
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Well there is NO such concern but as in code its not specified that PT need to carry from face side not from root side so during discussion it was came that PT / MT shall be carry out from both side if its accessible.
But normally we use to carry PT from out side only if its not specified in client specification or in approved procedure.
RE: PT / MPI for root Weld
PT on the root, before hotpass is not a good idea. You have a much greater chance of inducing hydrogen in to the weld and you be asking for porosity. The welder will probably clobber you if you try this haha.
Dry MT is the only way to go for root NDE. The root cannot cool down too much before the hot pass or you are going to be a great risk for cracks.
Again, it depends on material type, size and sch.
Just my 2 cents.
East