I have to qualify the following combination
Nozzle Pipe thickness - 7.62mm -(SA 106 )
Shell thickness - 50mm - (SA 516 Gr70N)
Impact testing applicable at minus 46 deg C.
Wherever there is Single V we intend to use the combination of GTAW and SMAW.
Where there is Double V we intend to use only SMAW accompanied by Back chipping.

Can any one confirm,
1) The combinations applicable.to cover the complete range from 7.62mm to 50mm
2) The location of the test pieces (tensile & Impact) within the welds.

Also I am a bit confused about interpretation of clause QW 200.4(b) in this regard
since QW 403.6 and QW 200.4(b) cannot be satisfied at the same time for the above combination.

SantoshC,

sounds tricky, but not really problematic. I am assuming you plan to fabricate a set-on nozzle weld, so

What about welding a test piece of 7,5 or 8 mm to 40 or 50 mm as a butt joint, with 7,5 or 8 mm deposit weld thickness. machine off the exces thickness of the thick side, make your impacts, tensile and bend tests, and there you are, qualified a dissimilar thickness situation.

The same result can be achieved with combination of two PQRs.

DK

DK

Thanks for the reply, but it is a set in nozzle
i.e - 1) The nozzle wall thickness is 7.6mm the shell wall thickness is 50 mm
2) Deposited weld metal thickness is 5omm.

SanoshC,

In this case you got to qualify T (base metal thickness) for impact conditions, which means QW-403.6 applies.
Also, your t thickness shall be qualified. At the end of the story you will wind up with two or more PQRs qualifying the WPS for the thickness needed.

For example a 7mm test piece will qualify from 7 to 14, and another 40 mm test piece will qualify from 16 to 200. Just make sure that the heat input will be qualified correctly. And do not forget PWHT.

QUestion: will you PWHT over the upper transformation temp?

DK

DK
We will be carrying out PWHT as per UCS-56 and not at Upper critical temperature.
I am considering the following combination.
1) PQR-1 : 45thick plate out of which 22.5mm by GTAW & 22.5mm by SMAW,
PWHT followed by testing for qualification including impact test for both the procedures.
This will cover range from 16mm to 200mm for base metal for both the procedures.
2) PQR-2 : 10 thick plate by GTAW testing similar as above.
This will cover
GTAW : Base metal 10mm to 20mm
Weld Metal max 20mm
3)PQR-3 : 6mm plate completely by PWHT & Testing Similar as above.
This will cover
GTAW : 6mm to 12mm
Weld metal max 12mm.
Can I use a WPS qualified by the above PQR 1,2 & 3 to carry out

1) GTAW Welding : Weld Deposit max 20mm for parent metal from 6mm to 20 mm and 2)Combination of GTAW andSMAW for thickness above 20 mm upto 200 mm within the limits of deposit.

SantoshC,

sounds good so far, but what about the set in nozzle,
will you weld it TIG only? That would be qualified, but SMAW is not qualified for the thickness of the nozzle.

Dk

DK
Yes Sir, I think I will have to add 2 more PQR's in 6mm and 10 mm in SMAW to cover the complete range required by me.

Thank You Very Much taking time to read my queries and replying back.
Thank You once again.