Weldolet to be welded to a pig launcher 1

[sayee1]

We recently had a 16" x 12" weldolet welded to a pig launcher fabricated as per ASME Section VIII div 1. Does Section VIII div 1 does not allow for weldolet usage? Also if the weldolet is welded to the pig luncher pipe which is 16" dia and something like 15 mm WT, what should be the qualified base metal thickness range of the WPS to be used for this welding? Remember that the weldolet thickness would be in excess of 40mm. Also what should be the nominal weld thickness to be considered for the welding? If it is more than 40 mm as given above would it necessiate the need for PWHT? Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

 

[deanc]

See thread725-43222 in Welding

 

[sayee1]

DeanC,
Thanks for the links, the queries and replies on the link and another one the link led to were really very helpful. But an additional question! the reason why I aked is that I used Section VIII design calculations to proove that a partially welded weldolet is sufficient(Rememeber here we are not using rf pads). But even then what I would like to clarify i that if the weld nominal thickness exceeds 2 times the wt for which PWHT needed(19 mm as per 31.3) or say 38 mm as per VIII div1, would it necceiate PWHT? Anyone with any experience on this? and what shd the thickness considered for checking the WPS to be valid or not? Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

 

[LSThill]

HI sayeeprasadr (Materials)

FOR THE CALCULATION USE FE/Pipe

http://www.paulin.com/newprg/fe_pipe.htm

Paulin Research Group 11211 Richmond Avenue. Houston, TX 77082 Phone: 281-920-9775 Fax: 281-920-9739
info@paulin.com


In contrast to traditional finite element modeling, where the analyst must build the model from scratch, FE/PIPE uses pre-fabricated templates for piping and vessel components. A library of component templates is available for Piping Intersections, Nozzles (in Flat Plates, Cones, Tanks, Heads, including Hillside Nozzles), Reinforcing Pads, Stanchions on bends, Piping Supports, Lugs, etc. The Shell String Modeler allows one to model connected Piping and Vessel segments. This includes mitered elbows, bends, reducing elbows, cylindrical and conical segments, annular plates, and spherical or elliptical heads. The latest version includes templates for a shell containing multiple nozzles, a pad reinforced fabricated cross, structural elements, and API storage tanks, nozzles and base settlement. The Plate Processor allows user defined plate attachments (lugs, saddles, shoes etc) for shell and nozzle elements. Large complex geometries may be built up by combining several smaller &quot;child&quot; models to a &quot;parent&quot; model. This is done by defining common nodes between models. The recent addition of 8-node Brick Templates allows one to perform thick wall (D/t < 10) analysis. 32-bit processing and graphics have speeded up the program by 2-3 times. There is also automated animation, Quick Calc feature for WRC107/297 and N318/392, a thermal profiler for unreinforced fabricated tees, and reinforcing pad options for hillside nozzles and bends with stanchions.

What are specific areas where a FEPipe calculation is needed? In summary, the following examples illustrate areas where FEPipe can significantly improve on existing more simplified design methods.

- Validation of pressure designs in large d/D intersections
- Allowable load determination on nozzles.
- Replacement Method for WRC 107 or WRC 297
- Cyclic applications (>5000 cycles)
- Large hillside or lateral nozzles.
- Nozzles subject to high temperatures and the potential for elastic follow-up. (>800 deg.F)
- Transverse or Axial loads on saddles.
- Bends with staunchions or structural weldments
- Transient Thermal (and thermal+pressure) loading conditions.
- Stiff systems interacting
- SIF's for non-code geometries, or for geometries outside of Code limits, and geometries not addressed by the code.
- Jacketed Piping systems
- Fixed tubesheet designs
- Collapse of thin walled piping geometries
- Stress distributions around multiple openings

FEPipe is a template driven finite element program designed exclusively for the piping and petrochemical markets. FEPipe handles saddles for axial or lateral loads, a result that Zick could never do, and find stresses in lugs and attachments in the automodeller. FE/Pipe will also produce allowable loads on nozzles which can then be handed to the piping engineer for evaluation. The new version FEPipe 4.100 does a spectacular job with multiple, close proximity nozzles in heads or cylinders using unstructured meshing.

It's known that B31 Appendix D is only justified for D/T<100. For thin walled pipe, FE/Pipe is the only tool available that will make a direct calculation of the sif and flexibility. FE/Pipe handles the thermal gradient requirements of 301.7.2, and the cyclic load requirements of 301.10. This is where the real failures occur and if the structure cycles then an accurate calculation of the loads and stresses is important. If your work involves API 579 the required membrane and bending stress determinations are found directly in FE/Pipe using Pl and Qb as described by Bergreen. You can even incorporate patches of localized corrosion/erosion and dents.

Shoule take less then 5 mimits.

Leonard@thill.biz

http://www.thill.biz