I've been having some disagreements with colleagues regarding fillet weld sizing on the back-side of fabricated lap joint stub-ends for use with standard ASME B16.5 lap joint flanges on ASME VIII-1 equipment. Any other perspectives would be much appreciated.
Perspective #1:
ASME B16.9 Table 6.1-9 provides dimensions for off-the-shelf one-piece stub ends. This table provides a dimension for the radius on the back-side of the stub end (dimension R). These stub-ends are intended for use with standard B16.5 lap joint flanges. Since we are using standard B16.5 flanges, we should be producing fabricated stub-ends to a geometry matching those of B16.9 stub ends. To that end, the fillet weld on the backside of the lap ring should be radiused and match the sizing of B16.9 Table 6.1-9.
Perspective #2:
As this is a fabricated stub-end rather than a one-piece machined stub end, we do not have to follow the dimensions of B16.9. Because this equipment is for an ASME VIII-1 application, we should weld on the lap ring according with ASME VIII-1 Figure 2-4 (1a).
Application - This is for titanium construction, and off-the shelf stub-ends are not readily available in the sizes we need. The pipes are very thin-wall (4" w/ 0.120" wall). If we were to go with B16.9 stub end sizing, this would require a 0.44" radiused weld, which is very thick compared to the pipe wall. If we go with ASME VIII-1 Figure 2-4 (1a), we could get away with a 0.12" simple fillet weld.
What do you all think?
Thanks for any help you can provide!
Perspective #1:
ASME B16.9 Table 6.1-9 provides dimensions for off-the-shelf one-piece stub ends. This table provides a dimension for the radius on the back-side of the stub end (dimension R). These stub-ends are intended for use with standard B16.5 lap joint flanges. Since we are using standard B16.5 flanges, we should be producing fabricated stub-ends to a geometry matching those of B16.9 stub ends. To that end, the fillet weld on the backside of the lap ring should be radiused and match the sizing of B16.9 Table 6.1-9.
Perspective #2:
As this is a fabricated stub-end rather than a one-piece machined stub end, we do not have to follow the dimensions of B16.9. Because this equipment is for an ASME VIII-1 application, we should weld on the lap ring according with ASME VIII-1 Figure 2-4 (1a).
Application - This is for titanium construction, and off-the shelf stub-ends are not readily available in the sizes we need. The pipes are very thin-wall (4" w/ 0.120" wall). If we were to go with B16.9 stub end sizing, this would require a 0.44" radiused weld, which is very thick compared to the pipe wall. If we go with ASME VIII-1 Figure 2-4 (1a), we could get away with a 0.12" simple fillet weld.
What do you all think?
Thanks for any help you can provide!
