We have two individual WPS and supporting PQR's as below.
1.) WPS and PQR 1 : Process -GTAW, Thickness range : 1.5 mm to 20 mm,P No: 8
2.) WPS and PQR 2 : Process -SMAW, Thickness range : 1.5 mm to 20 mm,P No : 8

Question :
Can we use these two wps to cover a base metal thickess of 35 mm

If your PQR covers a base metal thickness that would permit welding on 35mm thickness you might be okay but if I read your question correctly you have 2 separate WPS qualified each (although different processes) up to 20mm in deposited thickness and again, an assumption, that the base metals were also 20mm in thickness?

If thats the case the answer is no, you would not be able to combine to get greater thickness. Remember, thickness variables address thickness of deposited weld metal as well as thickness of base metal. I discussed this same issue a few years back with an ASME Member (who is also a friend) and he set me straight making me feel a bit foolish in the meantime. Stick with the variables qualified.

djmc, read QW-200.4.

_________________
Konrad Anikiel

i assume PQR 1 & 2 are based on 10mm base metal if you welding a GTAW root and a SMAW fill & cap.... then welding a 35mm plate shouldnt be a problem i guess i may be wrong but gys please correct me