Level of hi-low in circunferential joints

[domiswain]

Hi dears, could you please tell me if according to API-1104, DNV, etc. the range for hi-low must be indicated in the wps and being a essential variable?

A client was asking about qualifying a coupon for minimum hi-low and one for the maximun hi-low in order to have a range qualified, but how does the level of hi-low affect in a welded circunferential joint?

Also in order to avoid hi-low levels to exceed the range we must to make sure the correct ovality of the pipes.

Thanks for your time and help


Eduardo Calva

 

[Kiwi2671]

Eduardo,
Misalignment (Hi-Lo) is not an essential variable of API 1104 but the code does have a maximum allowed (1/8" - 3 mm)
You could add that to your WPS for information purposes.
Misalignment is undesirable as it can make it very difficult for the welder to fuse both edges and Lack of Root Fusion is a rejectable defect,
Regards,
Kiwi

 

[Eddycurrentguy]

The 1/8" misalignment is predicated upon the wall thicknesses being equal. Larger variations are permissible as described in API 1104 Section 7.2