WPS Qualification with impact tests

[Fizza453]

Qualification standard is Section IX and Design Code is Section VIII-1.
PQR is made using SMAW and SAW.
May the HAZ of SMAW and SAW be combined in a single set of specimens, each specimen shall cover HAZ of both processes?
Similarly, may single set of specimens may represent both SMAW and SAW weld metal such that weld metal of SMAW and SAW is present in each specimen.
Kindly note that coupon thickness is less than 38 mm, so UG-84(h)(3) is not applicable.


Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[metengr]

May the HAZ of SMAW and SAW be combined in a single set of specimens, each specimen shall cover HAZ of both processes?

Yes, within the thickness limits of the weld deposited by each process.

 

[Fizza453]

In our case, thickness is not a limitation. Thickness of both weld deposit and base metal is enough that HAZ of SMAW and SAW may be represented by separate set of specimens. Intentionally, HAZ of both SMAW and SAW was covered in a single set of specimens, is it correct? any Code reference in either case if it is correct or wrong?

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[weldtek]

I'm not sure of your logic in this case. Is it because you are unable to get sufficient separation between the two processes and get distinct specimens representing each process, or is it just a question of convenience. If the latter applies, in my opinion, that would not be good work practice nor good engineering judgement. If you're wanting an explicit Code paragraph that spells this out you probably won't find it, however, if you carefully read QW 200.4(a) I think you'll get the idea that each process must be represented.
When you think about it, as fabricators, our efforts are directed toward developing and proving welding procedures that will produce acceptable and repeatable results. What good is a document that shows passing lab results if it doesn't result in acceptable production welds?

 

[metengr]

Fizza453;
Let me explain; you have to understand the function of a CVN impact test for a PQR qualification versus production impact test plates. For a PQR impact qualification you cannot use a single notch to qualify multiple welding processes and subsequent heat affected zones because each has to be treated separately. The base of the notch must be in the HAZ base material produced by the process.

For a production impact test plate, you can get away with testing the notch toughness of a heat affected zone produced by multiple processes because you are demonstrating the adequacy of notch toughness for a production weld joint using an impact qualified WPS.

This is why I stated yes earlier, if you have a specimen with multiple processes and heat affected zones, at the end of the day for a production impact test plate, you are testing one HAZ made by one or more processes as defined by the thickness deposited.

 

[Fizza453]

Thanks Metengr and Weldtek.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN