Joint efficiency of weld with nearby laminations in plate
Joint efficiency of weld with nearby laminations in plate
(OP)
Hello. My case is a pressure vessel with no design data (0,70 by default). An ultrasonic inspection of welding were performed in order to increase this value. However, there were found laminations in shell, reaching the shell-head weld, so increasing vessel joint efficiency is not that easy.
Does anyone know if there is a table of joint factors for welds with defects, or something similar to that? If it not, it seems like it won't be able to has a joint factor greater than 0,70.
Does anyone know if there is a table of joint factors for welds with defects, or something similar to that? If it not, it seems like it won't be able to has a joint factor greater than 0,70.





RE: Joint efficiency of weld with nearby laminations in plate
RE: Joint efficiency of weld with nearby laminations in plate
And you want to find some excuse to INCREASE the tank's original pressure rating? That's NOT a responsible action.
Why don't you repair the defects?
RE: Joint efficiency of weld with nearby laminations in plate
To make it clear, the weld has no cracks or other defects, this known by the Angular UT performed (probably a MT will be perform to ensure this). Laminations reachs the ZAC but are not inside the weld and nor cracks propagate from it.
And racookpe1978 I've said that if I don't have any Code/Fitness Analysis or something like that to increase the Joint Factor, it will be stay as 0,70, so don't judge.
RE: Joint efficiency of weld with nearby laminations in plate
Regards
r6155
RE: Joint efficiency of weld with nearby laminations in plate
RE: Joint efficiency of weld with nearby laminations in plate
RE: Joint efficiency of weld with nearby laminations in plate
1) to ensure that the weld has no defects (already tested with UT) a MT will be performed, and when finding it satisfactory JE will be increased
2) to evaluate laminations a fitness for service analysis per API 579 will be conducted, in order to determine that this defects of fabrication are acceptable for safely service
Thank you all
Regards
RE: Joint efficiency of weld with nearby laminations in plate
RE: Joint efficiency of weld with nearby laminations in plate
RE: Joint efficiency of weld with nearby laminations in plate
The laminations in the plate itself are my concern. Those defects should be ground out and re-welded to safe metal. Regardless of the joint. The metal AWAY from the joint needs to be as strong as intended by the original designer for the second user to pressurize the tank safely.
If you do not repair the tank wall, then the "actual" tank wall is only as "thick" as the distance from the outside of the wall to the nearest lamination. Basically, half the thickness you "think" you have measured.
RE: Joint efficiency of weld with nearby laminations in plate
The better questions would be why do you want to increase the joint efficiency, you can't re-rate the vessel with the lack of design and documentation. This is not limited to the US, pretty standard worldwide.
RE: Joint efficiency of weld with nearby laminations in plate
Thank you, regards