From P1 to P8

[Alex555]

Hello!
2 questions about Asme 9:
1. Can a welder who is certified to weld P1 weld P8?
I saw that QW423.1 says yes, but that doesn't make sense.
2. Can a plate welding certification also be a pipe certification?
In short - can a welder for CS plate weld SS pipe?
Thanks,

 

[IdanPV]

1. A change in P-Number is an Essential Variable for WPQ and WPS see QW-250 & QW-350.
2. Depends on welding position and pipe O.D, see QW-461.9.

 

[jrtei]

Hello!
2 questions about Asme 9:
1. Can a welder who is certified to weld P1 weld P8?
I saw that QW423.1 says yes, but that doesn't make sense.
2. Can a plate welding certification also be a pipe certification?
In short - can a welder for CS plate weld SS pipe?
Thanks,

Alex
1) Yes, P1 and P8 qualify for each other for performance. Qualification with any material from P1-P15F, P34, and P41-P49 will qualify for any P1-P15F, P34, and P41-P49 material. A welder qualified on P1 is good for P1-P15F, P34, and P41-P49 material.
2) Plate will also qualify them for pipe greater than 24"OD in the same position the plate qualifies them for. They would also qualify for pipe 2-7/8"OD and over but only in the flat regardless of the plate position qualified (exception being horizontal plate gets them horizontal also on the 2-7/8"OD and greater). Table QW-461.9 is very straight forward, see note 3 as well.

 

[IdanPV]

I am sorry. jrtei is right.
See QW-423.

 

[weldstan]

One must remmber that filler metal F-No can also be an essential variable in Welder Performance Qualification.

 

[DekDee]

One that has caught a lot of people out over the years is deletion of backing gas.
A welder qualified on P1 can weld P8 because backing gas will be added.
However, a welder qualified on P8 cannot weld P1 (unless all the CS joints are to be purged with backing gas)