Combination of Single Welded and Doube Welded Butt Joints

Osama · **Joined:** Thu Apr 02, 2009 9:38 am **Posts:** 59

Dear Sir,

My shell matrl is SA 387 Gr.11 Cl2. We have decided to weld all circumferential and longitudinal joints of shell courses with double welded butt joints (i.e. Double V)..

Problem lies where our fabricator approach the shell to tubesheet joint i.e. last joint of shell course and near to tubesheet joint.

Please advice if we can do a combination of weld joints i.e. all major joints of double V and two joints i.e. shell to tubesheet joints as single welded butt joints meeting criteria UW-35. Yes or No ?.

OR

I dont know if double welded joint is practically possible at this place i.e. shell to tubesheet joint location.

Shell thk = 30mm
Pressure = 33 kg/cm2g
Temperature = 450 deg. C
Matrl - SA-387 Gr. 11 CL2
Service is Fertilizer Process Gas (Shell and Tube sides are both with Process Gas)

leem817 · **Posted:** Thu May 21, 2009 8:35 pm

Shell to tubesheet weld be made as full penetration butt weld and it will comply with the requirement UW-35.

leem817

Osama · **Joined:** Thu Apr 02, 2009 9:38 am **Posts:** 59

Please if someone can answer the below mentioned issue:

Our fabricator apprehension is that a double welded butt joint is difficult near the shell to tubesheet joint i.e. last joint of shell course.

Please advice if we can perform a combination of weld joints:

All shell course i.e. circumferential and longitudinal joints with double V and last joint (no approach after tubebundle insertion) as single welded butt joints meeting criteria UW-35.

Can we apply above fabrication technique - Yes or No ?
OR

Burasothikul · **Joined:** Thu Dec 20, 2001 1:00 am **Posts:** 26

Quote:

Please if someone can answer the below mentioned issue:

Our fabricator apprehension is that a double welded butt joint is difficult near the shell to tubesheet joint i.e. last joint of shell course.

Please advice if we can perform a combination of weld joints:

All shell course i.e. circumferential and longitudinal joints with double V and last joint (no approach after tubebundle insertion) as single welded butt joints meeting criteria UW-35.

Can we apply above fabrication technique - Yes or No ?

Yesprovide that the root pass of single V can visually inspection as required by UW-35 and the welding procedure shall qualify. Para UW-9 requireds the joint preparation of groove weld shall design such as to permit complete fusion and penetration so that it can be considered as type 1 of table UW-12.

Combination of Single Welded and Doube Welded Butt Joints

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