length of under cut in B31.3

Date 02-20-2008 13:17

API 1104 clearly states the acceptance criteria required for the length of weld for undercutting where in B31.3, there are No any specific requirements with regards to length of the undercut. Only the depth was shown in ASME B31.3 table 341.3.2. Is it the discretion of the inspector to decide what is the length of undercut to be accepted or not or is there any other requirements of ASME B31.3 with regards to this subject matter?

By new tito (***)

Date 02-20-2008 14:22

If the length is not specified, then length is not a factor. Only the depth is mentioned, so in ANY length of undercut, only the portion that exceeds the acceptable depth is rejectable. For example: The undercut can be 12" long and be acceptable if no portion of it is deeper than specified.

By br549 Date 02-20-2008 15:29

B31.3:04 will give you three letter codes under table 341.3.2. Those are A, I, and H, depending service and conditions.

Therefore as far as length is concerned, it's all or nothing. As for depth, it's as specified per service and conditions. For instance if it is 1.5mm or less per 'I', then it can be the entire diameter of the weld as long as it does not exceed that depth. However; if you have a designation of A, there is none allowed period.