Eng-Tips is the largest forum for Engineering Professionals on the Internet.
Members share and learn making Eng-Tips Forums the best source of engineering information on the Internet!
-
Congratulations dmapguru on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
Welding C44300 to SA516-70 1
- Thread starter weldgal
- Start date
- Thread starter
- #3
-
1
- #4
- Thread starter
- #5
weldgal;
First off, for any weld repairs to an existing pressure retaining item you need or should follow an in-service repair code (in this case I recommend the National Board Inspection Code). Second, you need to confirm the materials of construction, and that includes the original tubesheet material. Do not guess and do not make recommendations unless you know the specific design conditions for this heat exchanger. Your weld repair should follow the requirements of the code of construction, which in this case is ASME, Section VIII, Div 1 requirements. Also, does your organization have a Certificate from the National Board to weld repair these types of pressure retaining items? If not, I would not perform this repair.
First off, for any weld repairs to an existing pressure retaining item you need or should follow an in-service repair code (in this case I recommend the National Board Inspection Code). Second, you need to confirm the materials of construction, and that includes the original tubesheet material. Do not guess and do not make recommendations unless you know the specific design conditions for this heat exchanger. Your weld repair should follow the requirements of the code of construction, which in this case is ASME, Section VIII, Div 1 requirements. Also, does your organization have a Certificate from the National Board to weld repair these types of pressure retaining items? If not, I would not perform this repair.
- Thread starter
- #7
Maybe I have been unclear. The repair will be performed per NBIC as our "R" stamp mandates. We are not guessing at the materials. The existing unit is a standard product that is no longer manufactured by the original fabricator. We have verified the performance of the C44300 materials, and they meet the performance criteria of the unit. I am questioning whether or not we should offer an alternate to the C44300 tubesheet if joining it to the SA516-70 shell could pose a problem.
weldgal;
Ok, now you are clear. If you offer an alternative material this could be construed as an alteration, see Part RC of the NBIC. An alteration opens a whole set of new issues that if you have an R-Stamp you should be well aware.
Are you sure the tubesheet is welded to the shell? Do you have any access to design documents or drawings for this heater that would help you to develop a repair plan?
Ok, now you are clear. If you offer an alternative material this could be construed as an alteration, see Part RC of the NBIC. An alteration opens a whole set of new issues that if you have an R-Stamp you should be well aware.
Are you sure the tubesheet is welded to the shell? Do you have any access to design documents or drawings for this heater that would help you to develop a repair plan?
- Thread starter
- #9
Customer can't even confirm that the existing unit is a U-stamped vessel. If we upgrade the material we'll still do it as a repair (per Appendix 6-2000 r). And the drawing is so illegible, we won't know about welding between tubesheet and shell unless we get the order (at bid stage).
Ok. Check with ASME Section II for allowable stress values and go with the Ni-Al-Bronze alloy for the tubesheet, ASME SB-171 UNS 63000. This alloy has good weldability and can be welded to carbon steel using an SFA 5.7 ERCu-Al A2 aluminum bronze filler metal. You most likely will need to qualify a WPS for this repair.
- Thread starter
- #11
- Status
Similar threads
- Locked
- Question
- Locked
- Question