What is the Governing thickness?
What is the Governing thickness?
(OP)
Hello All
SA 350 LF2 flange (At the forging shop) is found to have discontinuity (16" 900 #) on the Flange OD. The Discontinuity cannot be left un attended. The forging has to be saved (Insted of rejection) by repair welding.
The location of the defect is 17mm from the OD and the depth of the defect is 13mm.
What should be considered as governing thickness "T" for the purpose of qualifying the weld procedure? Which clause of ASME SEC VIII and ASME Sec IX address such repair issues.
Governing thickness for the purpose of repair of Material is not found in ASME Sec VIII Div 1. UW 40 addresses weld repair and not the base material repair.
SA 350 LF2 flange (At the forging shop) is found to have discontinuity (16" 900 #) on the Flange OD. The Discontinuity cannot be left un attended. The forging has to be saved (Insted of rejection) by repair welding.
The location of the defect is 17mm from the OD and the depth of the defect is 13mm.
What should be considered as governing thickness "T" for the purpose of qualifying the weld procedure? Which clause of ASME SEC VIII and ASME Sec IX address such repair issues.
Governing thickness for the purpose of repair of Material is not found in ASME Sec VIII Div 1. UW 40 addresses weld repair and not the base material repair.





RE: What is the Governing thickness?
For weld procedure qualification, I would use a 1.5" thick coupon to allow for 8" base metal and 8" weld deposit thicknesses. Otherwise, you could use a 1.5" thick coupon and limit the weld groove depth to the depth of the defect.
RE: What is the Governing thickness?
What you said is common sense. But which clause of Sec IX deals with the repair "T"
Now the Forging shop would certainly want to have the PQR done before hand and keep it ready so that when ever and where ever repair occurs they can start the repair.
If the repair had occured at 10mm from OD and the excavation is till 13mm then, qualifying a procedure in a 1.5" plate would not support the repair, if we perform PQRT with 1.5' plate.
Does it mean the manufacture shall have 3 PQRs, one for 1mm to 5mm and one for 5 to 16 and one for thickness from 16 till 8"? to attend the full range of thickness.
RE: What is the Governing thickness?
Getting back to your original post, the 1.5" thick coupon used for weld procedure qualification will allow for qualification on base metal up to 8" in thickness. This is why I suggested using a 1.5" thick, butt welded coupon. This way, your base metal thickness and weld deposit thickness are both good to 8" qualification with this WPS.
RE: What is the Governing thickness?
RE: What is the Governing thickness?
There is only 1 place in ASME sec VIII Div 1 that deals with the governing thickness for repair, which is in UW 40, which deals with PWHT.
Hence i was checking whether there are any interpretations in Sec 2 or in section VIII.
Thanks
RE: What is the Governing thickness?
if there were a 100mm thick plate and if there is suface flaw say 2mm deep and the purchaser agreed for repair, then is it necessary for the plate manufacturer to qualify in 5mm thick plate. Does it not look funny.
I think the matter is not addressed by either sec 2 or in section VIII div 1.
RE: What is the Governing thickness?
The WPS for weld repair should be developed based on the base metal thickness (100 mm) AND the weld deposit depth (any thickness at or below 100 mm). All you must do is to assure that during qualification of the welding procedure (using ASME Section IX requirements), the actual base metal thickness you are welding on falls within the range of the qualified base metal thickness in the WPS AND your depth of weld repair falls within the range qualified for weld deposit thickness in the WPS. PWHT or other essential variables like preheat must be included based on the Code of Construction (ASME Section VIII, Div 1).
RE: What is the Governing thickness?
You are not addressing the need of ASME certification/stamping to be allowed to weld on forgings. you have to look at the ASME specification for the type of flg you are forging toi see about repaiors by welding and if you are allowed to weld on the finished flange (repair by welding). at one time China mfrs were sending repaired flanges not only welded by filled with plastic/epoxy so they are banned from using this flanges in ASME construction... careful...
genb
RE: What is the Governing thickness?
RE: What is the Governing thickness?
RE: What is the Governing thickness?
We had a lot of weld testing and qualification done using weld coupons thinner than the actual parts, but with thickness that is "permissible" according to codes.
Now that we are having problems the bigh priced consultants are saying "well, sometimes your weld tests must match the thickness and restraint of the real parts."
RE: What is the Governing thickness?