QW-353/qw-402.4 backing not essential qw-253

[WE17]

Dear All

I need some help for understanding backing,
I have PQR qualified for GTAW(root)& SMAW(Fill+Cap)
So in my understanding according to ASME IX QW-402.4 SMAW(E 7018-1) and QW-402.5 GTAW(ER-70SG) in Production I can use my WPS with or without backing for GTAW and SMAW only applicable with Backing.

after re read the code and have discussion with friend I got little bit confuce please see qw-256)
GTAW QW-402.5 (+)Addition Backing nonessential
SMAW QW-402.4 (-) Deleting Backing nonessential

If me see the interpretation in production as per code in Production we can use also SMAW for root(let say 7018-1 or 7016) ? the limitation only for welder
QW-353/qw-402.4 .

Before my interpretation SMAW in Production for WPS must be always use backing ? and my logic said weld root more difficult than weld without root so whennever i qualified without backing i can automatic qualified with or without backing.
I highlight " Double-welded groove welds are considered with backing "
Please advice ?

Thanks n Regards

ario

 

[bpv66]

Backing is a non-essential variable for WPS qualification. You can record with and without backing on the WPS for both processes. However, backing is an essential variable for the welder. The welder must qualify SMAW without backing.

 

[WE17]

Hi bpv66

Appreciate for response bpv66 . so with going to asme code said that SMAW 7018-1 allow to weld root as well ?
in same case What about if me qualified with GTAW and SAW ? Can I make root with SAW ?
Anyway Thankyou bpv66 to redirecting me to the right way...

Thanks n Regards

AP

 

[bpv66]

The WPS would allow GTAW or SAW for root pass welding with or without backing per Section IX. You would only have to ensure the welder is qualified SAW open root.

 

[WE17]

Hi bpv66

Thankyou in advance for your advice. I agree with you, the summary minimum code asme will allow to make without backing but we need to
think about quality. better to do root with GTAW rather than SAW eventhough allow by minimum code.

Thanks bpv66