If you mean 8" Sch 80 carbon steel to 3xx stainless steel for a welder qualification, the welder is qualified up to 1" weld deposit thickness for the process and covers P-No 1 through P-No 8 base materials.
metengr
Thanks for your support and I did mean the sizes and schedules that you pointed out. My concern was that I would only be qualify for P1 connected to P8 material at that thickness range. So it means that I will be qualify to join P1-P1 and P8-P8 at the maximum of 1.00" because of the schedule and if the WPS has the same essentials?
He is covered for base metals, BUT, if they are using SMAW, the F number for E7018 and most stainless steel electrodes is different (F4 for 7018, F5 for 309, etc). So, if the welder qualified using an F5 electrode, he's likely not qualified from a filler metal standpoint when welding carbon to carbon with SMAW.
The process is GTAW ER309(L). This vessel is half solid 316 and the other half C/S with a cladding,but the cladding is not considered in the strength calculations just a corrosion barrier.
'So it means that I will be qualify to join P1-P1 and P8-P8 at the maximum of 1.00" because of the schedule and if the WPS has the same essentials?'
Assuming you use the same F# your welder will be qualified to weld P1 - P1 and P8 - P8.
Since you're welding a test coupon which is at least 1/2" thick, and assuming the weld will be made using at least 3 layers, the welder passing this test isn't limited to 1". Your WPS will determine the max qualified thickness.
The essential variables on the WPS do not necessarily apply to welder performance. For GTAW review QW 356 for essential variables.
